Mining Terms and Definitions

We see ourselves as humans who make things. Definitions have never done anything but constrain - Jonathan Safran Foer
This section presents a generous number of definitions that pertain to mining both open pit and underground.
ACID ROCK: - generally refers to an igneous rock carrying a high proportion of silica as content.
AERIAL SURVEY: - a survey made from a flying aircraft such as photographic, magnetometer, radioactivity, etc.
AGITATION: - in metallurgy, the act or state of being stirred or shaken mechanically, sometimes accompanied by the introduction of compressed air.
ALLUVIAL, ALLUVIUM: - deposits of sedimentary material laid down in river beds, flood planes, lakes, or at the foot of mountain slopes.
ALTERATION: - any physical or chemical change in a rock or mineral subsequent to its formation.
AMALGAM: - an alloy of mercury with another metal.
AMALGAMATION: - a process by which gold and silver are extracted from an ore by dissolving them in mercury.
AMORPHOUS: - a term applied to rocks or minerals that possess no definite crystal structure or form.
ANODE: - a rectangular plate of copper (or other metal) cast in a shape suitable for refining by the electrolytic process.
ANOMALY: - a term applied to a departure from the normal or field characteristic, commonly used in geophysical prospecting. Thus, in a magnetometer survey an area showing much higher (or much lower) readings of magnetic intensity than the surrounding area would be identified as an anomaly.
ANTICLINE: - an arch or fold in the layers of rock shaped like the crest of a wave, as opposed to a syncline which is similar to the trough of a wave.
APEX: - the top or terminal edge of a vein on a surface or its nearest point to the surface.
ASSAY: - to test ores or minerals by chemical or other methods for the purpose of determining the amount of valuable metals contained.
BACKGROUND: - the minor radioactivity shown by a counter which is not due to abnormal amounts of radioactive minerals nearby. The background is accounted for by cosmic rays and the minor residual radioactivity in the vicinity.
BACKSTOPE: - the initial lift or slice when commencing to stope or mine from a drift.
BALL MILL: - a piece of milling equipment used to grind ore into small particles. It is a cylindrical shaped steel container filled with steel balls into which crushed ore is fed. The ball mill is rotated, causing the balls themselves to cascade, which in turn grinds the ore.
BANDED ORE (STRUCTURE): - composed of bands or layers of minerals (rocks) differing in color and texture.
BASEMENT ROCKS: - the underlying or older rock mass. The favorable ore-bearing sedimentary rock formations lie on top of a granite basement; the hunt for ore, therefore, is restricted to the overlying rocks in this particular case.
BASE METAL: - a metal inferior in value to gold and silver, generally applied to the commercial metals such as copper, lead, etc.
BASIC ROCK: - an igneous rock, relatively low in silica and composed mostly of dark-coloured minerals.
BATHOLITH: - a large mass of igneous rock extending to great depth and with its upper portion dome-like in shape. It has crystallized below surface, but may be exposed due to erosion of the overlying rock. Smaller masses of igneous rocks are known as bosses or plugs.
BENEFICIATE: - to concentrate or enrich; generally applied to the preparation of iron ore for smelting, through such processes as sintering, magnetic concentration, washing, etc.
BENTONITE: - a clay which has great ability to absorb water and swells accordingly.
BIOLOGICAL LEACHING: - a process for recovering metals from low grade ores by dissolving them in solution, the dissolution being aided by bacterial action.
BIT: - the cutting end of a boring instrument.  In rock drilling, it is frequently made with ultra-hard material such as diamonds or tungsten carbide.
BLACKJACK: - a miner's term for sphalerite or zinc blende (ZnS).
BLAST FURNACE: - a metallurgical furnace in which mixed charges of oxide ores, fluxes, and fuels, are blown with a continuous blast of hot air and oxygen-enriched air for the chemical reduction of metals to their metallic state. Iron ore is most commonly treated in this way, and so are some ores of copper, lead, etc.
BLASTHOLE: - a hole drilled for purposes of blasting rather than for exploration or geological information. Blastholes can range in diameter from 1 inch to 36 inches depending on bit or auger size.
BLISTER COPPER: - the product of the Bessemer convertor furnace used in copper smelting.    It is a crude form of copper, assaying about 99% copper, and requires further refining before being used for industrial purposes.
BLOCK CAVING: - a cheap method of mining in which large blocks of ore are undercut, the ore breaking and caving under its own weight.
BONANZA: - very rich ore or situation.
BOULDER CLAY: - an unstratified deposit of clay in which are embedded rock particles up to the size of boulders; usually of glacial origin.
BOX HOLE: - a short raise or opening driven above a drift for the purpose of drawing ore from a stope, or to permit access.
BREAST: - a working face, usually restricted to a stope.
BRECCIA: - a fragmental type of rock whose components are angular in shape, as distinguished from a conglomerate whose components are water-worn into a round shape.
BULK SAMPLE: - a large sample, frequently involving many tons, selected in such a manner as to be representative of the material being sampled.
BULLION: - metal in bars, ingots or other uncoined form.
BULL QUARTZ: - a prospector's term describing a coarse-grained, barren quartz.
BYPRODUCT: - a secondary or additional mineral or mineral product.
CAGE: - the conveyance used to transport men and equipment in a shaft.
CHALCOPYRITE: - a sulphide mineral of copper and iron, being a common ore of copper.
CHANNEL SAMPLE: - a sample composed of pieces of vein or mineral deposit that have been cut out of a small trench or channel, usually about four inches wide and an inch or so deep. By taking channel samples at regular and close intervals, an accurate estimate of the grade of a deposit can be obtained.
COLLAR: - the term applied to the timbering or concrete around the mouth of a shaft; also in blasting terms, a term used to describe the top of a drill hole. For example, in underground drifting, explosives are usually loaded to the collar (no stemming at all).
COMPLEX ORE: - an ore containing a number of minerals of economic value, usually implying difficult metallurgy to extract them.
COMPRESSOR: - a machine for compressing air to a pressure sufficient to actuate mine machinery. In underground mining operations, compressors on surface usually supply air at pressures anywhere from 40 to 120 psi. With boosters, air pressures can exceed even 120 psi.
CONGLOMERATE: - a sedimentary rock consisting of rounded, water-worn pebbles or boulders cemented together into a solid mass.
CORE: - the long cylinder of rock, about one inch or more in diameter, that is recovered by the diamond drill. Common sizes of diamond drill core are AX/AQ, BX/BQ, NX/NQ, HX/HQ (CASING SHOES), EXT, HXT and XRP sizes.
CORE BARREL: - that part of a string of tools in diamond drilling in which the core specimen collects.
COUNTRY ROCK: - a loose term to describe the general mass of rock adjacent to an orebody, as distinguished from the vein or ore deposit itself.
CRUSHER: - a machine for crushing rock, such as a gyratory crusher, jaw crusher, stamp mill, etc.
CUT-AND-FILL: - a method of stoping in which ore is removed in slices, or lifts, following which the excavation is filled with rock or other waste material known as backfill, before the subsequent slice is mined; the backfill supports the walls of the stope.
CUT VALUE: - applies to assays that have been reduced to some arbitrary maximum figure; thus high erratic values would not appreciably increase the over-all average.
CYANIDATION: - a method of extracting gold or silver by dissolving it in a weak solution of sodium cyanide.
DEVELOPMENT: - the underground work carried out for the purpose of reaching and opening up a mineral deposit. It includes shaft sinking, cross-cutting, drifting and raising.
DIABASE: - a common basic igneous rock usually occurring in dikes or sills.
DIAMOND DRILL: - a rotary type of rock drill in which the cutting is done by abrasion rather than percussion. The cutting bit is set with diamonds and is attached to the end of long hollow rods through which water is pumped to the cutting face. The drill cuts a core of rock which is recovered in long cylindrical sections, an inch or more in diameter.
DIKE: - a long and relatively thin body of igneous rock that, while in the molten state, has intruded a fissure in older rocks and has solidified.
DISSEMINATED ORE: - ore carrying small particles of valuable minerals, spread more or less uniformly through the gangue matter; distinct from massive ore wherein the valuable minerals occur in almost solid form with very little waste material included.
DRAG FOLD: - where rock has been folded or bent back on itself.
DRIFT (DRIVE): - a horizontal passage underground that follows along the length of a vein or rock formation as opposed to a crosscut which crosses the rock formation.
DRIFTER: - a rock drill used for boring horizontal holes for blasting.
ELECTROLYTIC REFINING: - the process of refining metals by casting into anodes which are placed in an electrolyte consisting usually of a salt of the same metal dissolved in water, and depositing on a cathode by passing an electric current into the system; similarly, by using an electrically inert anode, and depositing the metal on the cathode from a purified solution of a salt of the metal.
EN ECHELON: - a term used to describe a formation in which the occurrences are found in roughly parallel but staggered fashion. In blasting, production blastholes are fired row by row, or in staggered fashion using delays so that the firing sequence is such that holes are fired obliquely to the free face with the face moving out as one unit and rolls out.
EROSION: - the breaking down and subsequent removal of either rock or overburden surface material through the forces of nature.
EXPLORATION: - the prospecting, diamond drilling and other work involved in searching for ore.
FACE: - as applied to a drift, crosscut or stope, is the end in which work is progressing.
FEEDER: - a mechanical device, usually automatic, for a regular and controlled supply of process materials to a machine; also applies to the controlled feeding of reagents to processes.
FLOAT: - pieces of rock that have been broken off and moved from their original location by natural forces such as frost action or glaciation.
FLOTATION: - a milling process by which some mineral particles are induced to become attached to bubbles and float, and other to sink. In this way the valuable minerals are concentrated and separated from the worthless gangue.
FLOWSHEET: - the sequence of operations, step by step, by which ore is treated in a milling, concentration, or smelting process.
FLUX: - a chemical substance used in metallurgy to react with gangue minerals to form slag material which is liquid at the furnace temperatures concerned and low enough in density to float on the molten bath of metal or matte. Examples range in scale from large tonnages of limestone, silica, etc., in large furnaces, to small quantities of borax, soda, etc., used in laboratory assay fusion samples.
FOOTWALL: - the wall or rock on the underside of a vein or ore structure.
FREE MILLING: - ores of gold or silver from which the precious metals can be recovered by concentrating methods without resort to roasting or chemical treatment.
FRICTION HOIST: - a mine hoist in which conveyances such as cages/ore carriers etc., are suspended from both sides of a simple friction pulley which provides the desired motion. It is not to be confused with a drum hoist in which the ropes are wound onto their individual elevating drums.
GABBRO: - a coarse grained dark igneous rock.
GALENA: - a sulphide mineral of lead, - a very common lead ore.
GAMMA: - a unit of measurement of magnetic intensity.
GANGUE: - the worthless minerals associated with valuable minerals in an ore deposit.
GEIGER COUNTER: - an instrument used in the search for radioactive minerals, particularly uranium. The main component of this instrument is a Geiger-Mueller tube which detects the rays emanating from such minerals. A Geiger Counter registers the frequency or intensity of these rays either visually (by dial or flashing light), or audibly (by earphones) or both.
GEOLOGY: - the science concerned with study of the rocks which compose the earth.
GEOMECHANICS: - see rock mechanics.
GEOPHYSICAL SURVEY: - a scientific method of prospecting that uses the physical properties of minerals to detect their presence. Common properties of minerals that can be investigated include magnetism, specific gravity, electrical conductivity and radioactivity.
GLACIAL DRIFT: - sedimentary material consisting of clay and boulders which has been conveyed by glaciers.
GLACIAL STRIAE: - lines or scratches on smooth rock surfaces - caused by glacial abrasion.
GLORY HOLE: - a large open pit from which ore is extracted, - specifically a situation which involves passing broken ore underground workings before being hoisted.
GNEISS: - a layered or banded crystalline metamorphic rock whose grains are aligned or elongated into a roughly parallel arrangement.
GOSSAN: - the rust coloured oxidized capping or stain of a mineral deposit, generally formed by the oxidation or alteration of iron sulphides.
GRAVITY METER, GRAVIMETER: - an instrument for measuring the gravitational attraction of the earth which varies with the density of the rocks in the vicinity.
GREENSTONE: - a field term used to describe any fine-grained green volcanic rock, most often applied to andesite.
GRIZZLY: - a grating (usually constructed of steel rails) placed over the top of a chute or ore pass for the purpose of stopping the larger pieces of rock or ore from building up in the jaws of the crusher.
GROUTING: - the process of sealing off a water flow in rocks by forcing thin cement slurry, or other chemicals into the crevices. Diamond drill holes are usually used to provide access to the area pinpointed for grouting since they can be directed using in-hole wedges.
HEMATITE: - an iron oxide mineral, one of the commonest ores or iron. When pure, it contains about 70% metallic iron.
HIGH GRADE: - very rich ore. Selective mining of the best ore in a deposit. High Grading may yield significant profit margin at first, however it is important to pay due attention to good mining practice to avoid inheriting potential mining problems when the rich ore areas run out.
HOIST: - the machine used for raising and lowering the cage or other means of conveyance in a shaft. Friction hoists and drum hoists are the most common types of hoisting equipment.
HORSE: - a mass of waste rock lying within a vein or orebody.
HOST ROCK: - the rock containing an ore deposit.
HYDROMETALLURGY: - separation of the metal in a mineral ore in aqueous solution from the rest of the ore, - followed by precipitation in metallic form.
IGNEOUS ROCKS: - rocks formed by the solidification of molten material that originated within the earth.
INDUCED POLARIZATION: - a method of geophysical surveying on the ground (at ground level as opposed to aerial surveying) employing an electrical current to determine whether sulphide mineralization has taken place.
INDUSTRIAL MINERALS: - usually non-metallic minerals which are used in industry and manufacturing processes in their natural state. Such minerals may be further processed marginally to meet some particular or specific end use specification. Examples include asbestos, salt, gravels, building material, talc, sands, etc.
INTRUSIVE: - a body of igneous rock formed by the consolidation/cooling of magma intruded into other rocks through fissures and/or seams contained in the rock mass. This is in contrast to lavas, which are extruded upon the surface.
JAW CRUSHER: - a mining rock crushing machine in which the rock is broken by the action of moving steel jaws.
KEEWATIN: - a term given to the oldest of Precambrian series of rocks.
LAMPROPHYRE: - a rock which is composed of dark minerals and occurs in the form of intrusive dikes.
LEACHING: - a chemical process used in milling for the extraction of valuable minerals from ore; also, the natural process by which ground waters dissolve minerals, thus leaving the rock with a smaller proportion of some of the minerals than it contained originally. Dump leaching can employ the use of explosives where rock is blasted in place, with dissolving solutions being introduced in the broken mass and then collected and refined.
LENS: - generally used to describe a body of ore that is thick in the middle and tapers towards the ends.
LIMESTONE: - a bedded sedimentary deposit consisting chiefly of calcium carbonate deposited from ancient marine life (shellfish).
LIMONITE: - a brown hydrous iron oxide.
LINE CUTTING: - a straight line cleared through the bush to permit sights to be taken for geophysical and other surveys.
LINE DRIVE: - a horizontal opening which is driven along a straight course, usually along the strike of the rock formations.
LODE: - a mineral deposit found in solid rock.
LONG TON: - by definition - contains 2,240 pounds avoirdupois.
SHOCK ANGLE: - a term used in BLASTCALC which is the angle subtended by the radial detonation velocity and the primacord detonation velocity of a traced explosive charge.    The actual detonation front travels obliquely to the axis of the longitudinal charge when boreholes are traced with primacord having sufficient initiation strength. This procedure tends to reduce the characteristic detonation velocity of the explosive charge loaded in the traced borehole.
MAGMA: - the molten material deep in the earth from which rocks are formed. Magma can flow through fissures in the earth's crust to form active volcanoes.
MAGNETIC SEPARATION: - a process in which a magnetically susceptible mineral is separated from gangue minerals by applying a strong magnetic field. Ores of iron are commonly treated this way. Equipment designed to accomplish this task are called Magnetic Separators.
MAGNETITE: - a term describing magnetic iron ore. It is a black iron oxide containing 72.4% metallic iron when pure.
MAGNETOMETER: - a sensitive instrument used to measure the magnetic attraction of underlying rocks.
MARGINAL ORE DEPOSITS: - orebodies approaching the lowest limits of commercial work-ability/mining economics.
MATRIX: - can be defined as the rock or gangue material containing ore minerals.
MATTE: - the product of a smelter, - constituent metal with some contained sulphur.    It must be further refined to obtain the pure metal.
METALLURGY: - the various methods of preparing metals for refining by separating them from their ores.
METAMORPHIC ROCKS: - rocks that have undergone a change in texture or composition subsequent to their first solidification, through interior processes such as heat, pressure, etc.
METAMORPHISM: - a geological term applied to the composition, texture, etc., of a rock, especially through interior processes of heat and pressure.
MILL: - a plant in which ore is treated for the recovery of valuable metals, or concentration of the valuable minerals into a smaller bulk for shipment to a smelter or other reduction works. The term MILL also applies to a grinding machine consisting of a revolving drum, for the fine grinding of ores as a preparation for further processing and treatment.
MINERAL: - a naturally occurring homogeneous material having definite physical properties and chemical composition and, if formed under favorable conditions, a definite crystal form.
MUCK: - ore or rock that has been broken by blasting.
MUSKEG: - decayed vegetable matter and black soil forming swampy areas.
NATIVE METAL: - a metal which has occurred in nature pure or uncombined with other substances. Common examples include native copper and native gold.
NUGGET: - a water-born piece of precious metal, usually having a significant size.
OPEN CIRCUIT: - an arrangement of a machine/process and its output control without involving the return of part of the product to the head of the machine or the beginning of the process; - opposite of closed circuit.
OPEN CUT: - a surface working, open to daylight.
ORE: - a mixture of ore minerals and gangue from which at least one of the mineral composition can be extracted from the rest of the mixture for economic gain.
ORE DRESSING: - the treatment of ore by the removal of some of the waste materials.
ORE RESERVES: - the measured assets of a mine as to tonnage and grade. They may be classified as positive or proven, probable or possible, in decreasing degree of statistical confidence as to the accuracy of their expressed grade or grades; - other terms frequently applied include - measured, indicated, pillar ore, broken reserves, etc.
ORESHOOT: - the portion, or length, of the vein, or other ore structure, that carries sufficient valuable mineral that can be profitable to mine.
OUTCROP: - exposed rock or a mineral deposit that can be seen on surface, i.e., it is not covered by overburden or water, and can be reached without using mining methods.
OXIDATION: - a chemical reaction caused by natural forces that results in a change in the composition of a mineral. Reaction with oxygen, for example, can produce oxides of iron, copper, magnesium etc.
PARTY LINE: - refers to the underground mining laws, between two properties. Under most mining laws, an underground heading cannot be carried within a prescribed distance of a boundary without permission of the owners of the adjoining ground.
PEGMATITE: - a coarse-grained igneous rock usually irregular in texture and composition, similar to a granite in composition. It usually occurs in dikes or veins and sometimes contains valuable minerals.
PELLET: - a marble-sized ball of iron mineral combined with a matrix of clay material such as bentonite, and fused for hardness.
PICKET LINE: - a reference line, marked by pickets or stakes, established on a property for mapping and survey purposes.
PIG IRON: - defined as crude cast iron from a blast furnace.
PILLAR: - a block of solid ore or rock left in place for the purpose of supporting the walls or roof in an underground mine. In coal mines, the 'rule of thumb’ is to leave about 50% of the coal in the form of pillars in order to achieve an acceptable factor of safety. Pillars can be mined in hard rock mines, by sequencing the blasting in alternate stopes and by hydraulically backfilling those pillars that have been removed.
PITCHBLENDE: - an important uranium ore mineral, containing a high percentage
of uranium oxide. It is black in colour, possesses a characteristic pitch-like
or greasy lustre. It is correspondingly highly radioactive.
PLUTONIC: - this is a term which refers to rocks of igneous origin that have come from great depths within the earth.
PORPHYRY: - any igneous rock in which relatively large, conspicuous/obvious crystals (called phenocrysts) are set in a fine-grained matrix.
PORTAL: - defined as the surface entrance to a tunnel or mining adit.
PULP: - can be defined as fine pulverized or fine ground ore in solution.
PYRITE: - a hard, heavy, shiny and yellow coloured mineral, comprising a sulphide of iron.    It is a common sulphide, sometimes known as 'fool's gold'.
PYRRHOTITE: - a less common iron sulphide than pyrite, being specifically bronze in colour, as well as being magnetic.  It is sometimes associated with nickel, in which case it may be mined as a nickel ore.
RADIOACTIVITY: - a property of radioactive minerals resulting in the spontaneous emission of alpha, beta or gamma rays by the disintegration of the nuclei of atoms. An example of such a radioactive substance would be pitchblende.
REAMING SHELL: - a component of diamond drilling equipment found on the drilling rods.    It is a hollow piece of tubing of pipe containing a hard metal ring in which diamonds are set within a metal matrix.  It is always positioned between the bit and the core barrel to maintain the gauge of the hole.
RECOVERY: - can be defined as the percentage of valuable metal contained in the ore that is recoverable by metallurgical treatment.
REFRACTORY ORE: - one that resists the action of chemical reagents (at high temperatures) in the normal treatment/refinement processes, and which generally requires roasting or other means to effect the full recovery of the valuable minerals.
REPLACEMENT OREBODY: - an orebody formed by a geological process during which certain minerals have passed into solution and have been carried away, while valuable minerals from the solution have been deposited in the place of those removed.
RESISTIVITY SURVEY: - a geophysical technique in which the resistances of minerals (in-situ) are measured using a special electronic instrument in order to establish conductivity of the particular geological formation being studied
REVERBERATORY FURNACE: - a long, flat furnace used in smelting copper concentrates. The principal function of this type of furnace is the slagging of gangue minerals, and the production of matte.
ROASTING: - the treatment of ore by heat and air, or oxygen-enriched air, in order to remove sulphur, arsenic, and other impurities.
ROCK: - any natural occurring combination of minerals forming an appreciable part of the earth's crust.
ROCKBOLTING: - the act of consolidating roof strata by means of anchoring and tensioning steel bolts in holes especially drilled for the purpose. In addition to rock bolting, safety screen is also applied the to roof and partial sides of an underground drift or stope in order to prevent 'loose' from falling and injuring mining personnel.
ROCK FACTOR: - an inverse expression of the density of a rock or an ore, as x cubic feet per ton; useful particularly in tonnage computations; ranges from 12.0 cu. ft. for highly siliceous ores, to 9.0 cu. ft. or less, for heavy sulphides.
ROCK MECHANICS: - the study of stress conditions surrounding mine openings, and the ability of rocks and underground structures to withstand imposed stresses. Rock mechanics attempts to model the in-situ stress field conditions so that extremely hazardous situations such as rock bursting and ground falls/outbursts can be either anticipated, or avoided.
ROD MILL: - a rotating cylindrical mill or drum which utilizes steel rods as a grinding medium.
ROOM AND PILLAR: - a method of mining flat-lying oriented deposits in which mining areas or rooms are separated by pillars of approximately equal size.
SANDSTONE: - a sedimentary rock composed of fine grains of quartz, etc., which have been cemented together.
SCARP: - an escarpment, cliff or steep slope along the margin of a plateau, mesa or terrace.
SCHIST: - a foliated metamorphic rock whose grains have a roughly parallel arrangement; it is generally developed by shear type forces.
SCINTILLATION COUNTER: - an instrument used for detecting and measuring radioactivity by detecting the gamma rays. This instrument is much more sensitive than the Geiger Counter.
SECONDARY ENRICHMENT: - can be defined as an enrichment of a vein of orebody by minerals which have formed a solution from one part of the vein or adjacent rocks and redeposited in another.
SEDIMENTARY ROCKS: - a classification of secondary rocks formed from rock particles which are laid down under water sometimes originating from marine life (limestone), eg., limestone, shale, sandstone. A characteristic feature of sedimentary deposits is a layered structure known as bedding or stratification. Bedding can be thin or thick depending on the processes involved.
SEISMIC PROSPECTING: - a geophysical method of prospecting utilizing the knowledge of the speed and reflection of sound waves in rock. Explosives and/or mechanical means are used to provide the acoustic source required to generate the type of waves that propagate through the rock strata. Highly sensitive geophones are used to pick up the minute vibrations in order to translate arrival times into the layering profiles that may hide or mask underlying geological deposits of oil or gas etc.
SHALE: - a classification of sedimentary rock formed by the consolidation of mud or silt.
SHEAVE WHEEL: - a large grooved wheel placed in the top of a headframe in an underground mine, over which the hoisting rope passes.
SHORT TON: - by definition, contains 2,000 pounds avoirdupois.
SHRINKAGE STOPE: - a method of stoping which uses part of the broken ore as a working platform and as support for the walls. Miners are continually working previous blasted areas. This type of mining is usually attempted only in very competent rock.
SIDERITE: - defined as iron carbonate, - an iron ore that contains 48.2% iron when pure.    Before it can be used in a blast furnace, it must be roasted to drive off the contained carbon dioxide. The resulting product after roasting is called sinter.
SILICA: - an oxide of silicon, of which quartz is a common example.
SILICEOUS: - a term defining a rock containing an abundance of quartz.
SILL: - an intrusive sheet of igneous rock of approximately uniform thickness and generally extending over a considerable lateral extent. Generally, it has been forced between level, or gently-inclined beds.
SILT: - a general name for muddy deposits of fine sediment usually found on the bottom of lakes.
SINTER: - the heat treatment of fine ore particles at very high temperatures to produce larger particles for blast furnace feed.
SKIP: - a self-dumping type of bucket used in a shaft of an underground mine for hoisting broken ore or rock.
SLAG: - the vitreous mass separated from the fused metals in a smelting process. Slag is waste material, but in many underground mines it is reused as part of the hydraulic fill which replaces the ore that has been previously removed.
SLASH: - defined as rock blasted from the side of a drift, resulting in the widening of the opening. It may be done to more accurately define the width of the ore, or merely to make more working room.
SLICKENSIDE: - can be defined as the striated polished surface of a fault caused by one wall rubbing against the other.
SPHALERITE: - can be defined as a sulphide mineral of zinc, - a common zinc ore.
SQUARE SET: - a set of timbers used for support in underground mining, consisting of cap, girt and post.
STATION: - an enlargement of a shaft or drift made at the level horizon used primarily for the storage and handling of equipment. Can also be used to house electrical transformers for the delivery of mine power underground. Such stations are heavily screened and rock bolted.
STOCK PILE: - broken ore that has been accumulated from blasting operations, either from underground mining operations or open pit operations, and stored on surface pending treatment or shipment.
STRINGER: - a narrow vein or irregular filament of mineral crossing a rock mass.
STRIP (STRIPPING): - removing the overburden or barren rock immediately overlying an orebody. Carefully planning is done to insure that only the minimum amount of stripping is done with due regard for stability, in order to maximize the economic return for the ore.
SUB-LEVEL: - an intermediate level or working horizon in an underground mine, - opened between main working levels.
SULPHIDE: - a compound of sulphur and other elements to form sulphide based minerals.
SUMP: - an excavation underground for the purpose of catching or storing water. The bottom of a shaft is commonly used for this purpose. Sumps are also found in surface mining operations such that water must be pumped from the designated sump area to ground level to minimize flooding of the open pit operation.
SYNCLINE: - defined as a down-arched fold in bedded or stratified rocks.
TACONITE: - a term common on the Mesabi iron range for a siliceous iron formation, containing magnetite and hematite, that has to be concentrated to make it into a useable iron ore. Taconite is an extremely hard material.
TAILINGS: - material rejected from a mill after the recoverable valuable minerals have been extracted. Tailings consists of fine particles of waste rock material that forms an aqueous slurry which is usually pumped out from the mill to a Tailings Pond, where, in time, much of the water content is lost
TALUS: - a heap of broken coarse rock found at the foot of a cliff or mountain
THICKENER: - a large round tank in a mill for the separation of solids from a solution. The clear liquid overflows the tank whereas the rock particles sink to the bottom.
TRAM: - to haul cars of ore or waste in an underground mine.
TRENCH: - a long, narrow excavation dug through overburden, or blasted out of rock, to expose a vein of ore structure.
BACKBREAK: - fragmentation and fracturing of host rock by blasting beyond the intended line of break. In open pit mines, as pits get deeper, excessive overbreak inherited from the start of the mining process can lead to slope failure which has the potential of inflicting both safety and economic hardship. In underground mines, it becomes imperative that excessive backbreak be eliminated to avoid damage to support pillars. Well managed blasting operations, taking into account both charge weight/delay and blast timing, can effectively eliminate and/or reduce backbreak so safety and economics are not compromised.
BERM: - a horizontal shelf or ledge built into an embankment or sloping wall of an open pit or quarry to break the continuity of an otherwise long slope for the purpose of strengthening and increasing stability of the slope or to catch or arrest slough material.    Blasting operations should be designed so that excessive vibration levels are reduced or eliminated so that the berms themselves remain intact and do not become a safety hazard.    Berms should never be undercut.
BOREHOLE PRESSURE: - the peak effective pressure caused by expanding gases that acts behind the detonation head on the cylindrical surface area of the borehole during a detonation; approximately equal to one half of the detonation pressure - for a fully confined explosive charge. The borehole pressure for the fully confined case is equal to the thermochemical pressure which is defined as the expanded detonation pressure that can do work on the borehole wall or any other confining medium. If the explosive is not fully coupled to the borehole wall, either through air, water, or some other medium, the borehole pressure is much attenuated from the confined case, typically at least an order of magnitude lower than one-half the detonation pressure. The magnitude of borehole pressure depends on rock characteristics such as Poisson’s ratio and tensile strength.
BUFFER BLASTING: - a controlled blasting technique typically used in conjunction with the main production blast where the last row of boreholes has a reduced burden, spacing and explosives load. By itself, the degree of control achieved may be inadequate, particularly if the host rock is highly fragmented. If used near a final wall, a preshear line would be utilized to terminate any cracks leading from the buffer row to the preshear line.
BULK STRENGTH: - a measure of performance of an explosive based on the number of energy units per unit volume of explosives relative to 100 energy units/unit volume of ANFO at a known density (usually defined for ANFO as 0.85 gm/cc). ANFO is an abbreviated form for Ammonium Nitrate.
BURDEN: - the distance between the explosive charge and the free face of the material to be blasted, or the distance to the next row of boreholes in the direction of blast progression.
BOREHOLE COLLAR: - the unloaded portion of a blasthole extending from the surface down to the top of the explosives column. To avoid excessive airblast and scabbing at the top of the borehole, sand, aggregate or some other inert material is used as a borehole filler in order to provide increased confinement. In some parts of the industry, collar is also referred to as stemming.
COMPRESSIVE STRENGTH: - the amount of compressive stress that a rock can withstand under uniaxial loading without failing. Determination of the compressive strength of a specific rock type can become quite difficult if there are substantial cracks and flaws in the sample. Normally, only competent samples are tested and hence may present a somewhat prejudiced test result in favour of strength, when just the opposite is true. To partially defeat such a trend, many samples must be tested and results statistically averaged to provide strength numbers that are reasonable.
CONTROLLED BLASTING: - various techniques used to limit the amount of backbreak developed during the blasting phase of the excavation cycle by reducing the level of ground shock vibrations, and by terminating cracks due to expanding explosive gases by defining a perimeter limit such as a preshear line. CUSHION blasting, BUFFER blasting, PRESHEAR and POSTSHEAR are some of the methods used, in addition to the old standby methods of reducing charge weight/delay and blast timing to reduce destructive vibrations from opening shear zones and faults, as well as bedding planes, etc.
COUPLING RATIO: - the ratio of the volume of the borehole (excluding the volume of the collar) divided by the volume of explosive material. In normal practice this can be reduced to the following expression: COUPLING RATIO IS EQUAL TO THE RATIO OF THE SQUARES OF EXPLOSIVE DIAMETER AND BOREHOLE DIAMETER. For example, considering a 2.0-inch diameter cartridge loaded into a 2.5-inch diameter borehole would have a coupling ratio of 0.64 or 64%.
CRUSHED ZONE: - a region immediately surrounding a blasthole where the compressive strength of a specific rock type was exceeded by the compressive stress generated by an explosive charge placed in contact with the borehole wall. In quarry blasting, particularly in limestone, it is possible to see the "powder marks" left behind from the last production row. These marks are typically powdered rock, where the borehole pressure has been sufficiently high enough to crush the rock in the immediate area of the borehole wall since the compressive strength of the rock was exceeded. These "powder marks" that are often seen at the back of an open pit/quarry blast are sometimes referred to as "burn marks" or "burn holes".
CUSHION BLASTING: - a controlled blasting technique employed after the main production blast where the rock slope is trimmed to the planned excavation limit. This type of blast is also known as a postsplit blast since it just cleans up the perimeter because of the minimum burden generated after the main blast has been fired.
DECOUPLED CHARGE: - a charge which has a smaller diameter than the blasthole in which it is loaded; the coupling ratio is less than one. Decoupled charges are used in preshear or postshear controlled blasting applications. By decoupling the explosive charge from the borehole wall, the intensity of the thermochemical pressure from the surface of the detonating explosive charge is attenuated by gas expansion through the annulus around the charge and the borehole wall. This tends to lower the borehole pressure to values below the compressive strength of the rock, and prevents crushing of the borehole wall.
DETONATION PRESSURE: - the pressure exerted by the momentum of the detonation head as it propagates through the explosive material. The detonation pressure is dependent on explosive density, explosive detonation velocity and particle velocity. From flash X-Ray photography, it has been found that particle velocity tends to average out to be about 1/4 of the detonation velocity for most explosive types. Detonation pressure does not depend on charge weight. Impulse pressure, which is represented by the area under the detonation velocity - time curve, does depend on charge weight and geometry.
DRIVING FORCE: - those forces in a system which tend to cause failure. In any dynamic system described by an equation of state, - the sum of the driving forces is equal to the sum of the resisting forces.
DYNAMIC STRENGTH: - the amount of stress that a rock can withstand without failing, under changing loading conditions. Detonating explosive columns loaded in rock apply dynamic loads to the rock since the induced stress is constantly changing. It has been found that under these conditions using explosive charges as impulse loading generators, dynamic rock strength values are actually higher (prior to failure) than static rock strength values - by a factor which can vary from 1.4 to 2.8.
FACTOR OF SAFETY: - the ratio of the forces tending to resist failure to those forces tending to cause failure. To insure an adequate factor of safety, this ratio may be multiplied by 2 or 3 times or more to guarantee that resisting forces have a clear advantage over failure type forces.
FAULT: - a fracture or a fracture zone along which there has been displacement of the two sides relative to one another parallel to the fracture; the displacement may be a few inches or many miles. Perhaps one of the best known fault zones in the world, is the SAN ANDREAS fault which is constantly moving, and has been the source of some of the strongest earthquakes recorded in recent history. Faults experienced in mining are dangerous geologic structure which can wreak havoc in many mining situations particularly with underground mining operations. Their direction and structure must be known to ensure good, safe mining practices specifically when blasting operations are conducted in underground mines.
FOLIATION: - a crystalline segregation of certain minerals in a rock in a dominant plane due to metamorphism; schistosity, flow cleavage and fracture cleavage are considered as types of foliation.
FRACTURE: - a break in the continuity of a body not accompanied by movement on one side or the other, and not oriented in a regular pattern or system.
FRACTURE RADIUS: - from the explosive usage standpoint, this measurement represents the extent to which cracks propagate, due to hoop stress and gas expansion into cracks. The ultimate fracture or crack radius depends on rock type and strength, as well as the explosive characteristics such as diameter of charge, gas volume produced, and energy.
FREQUENCY RESPONSE: - the range of frequencies that can be sensed (within certain acceptable limits or errors) by a measuring instrument or device, without significant attenuation. For example, most common seismographs used for blast monitoring have a typical sensor response of about 2 - 250 HZ without signal degradation. This covers very well, the range of frequencies produced by blasting operations from surface mining situations.
GELATIN: - a type of explosive which has water-resistant 'gel* or gelatin type base; this makes it a waterproof, cohesive, plastic product. It was found (by ALFRED NOBEL) that NITROCELLULOSE when mixed with NITROGLYCERINE, produced a stable gelatin based material that not only produced cohesiveness, rather than a granular product, but also made the handling of this particular explosive product, safer - less sensitive to shock, as well as waterproof.
GRANODIORITE: - a plutonic rock (one that has cooled at depth) consisting of quartz, plagioclase, (andesine or calcic oligoclase) and orthoclase, with minor biotite, hornblende, or pyroxene; intermediate between quartz monzonite and quartz diorite; contains at least twice as much plagioclase as orthoclase.
HERTZ: - frequency measured in cycles per second.
IN-SITU STRENGTH: - rock strength measured in the ground or geological formation in which the host rock occurs (as opposed to laboratory testing). Special equipment is required for such testing involving overcoring and special jacking instrumentation.
JOINT: - a crack, fracture, or fused crack in rock along which there has been very little or no movement parallel to the crack. Joints can occur either singly, or more frequently in a set of joints, or system of joints.
LINE DRILLING: - a controlled blasting technique in which a row of closely spaced holes is drilled at the planned excavation limit. Such holes form a plane of weakness to which the final production row is designed to break. In some instances, it is common practice to load every 3rd or 4th hole with a decoupled charge that assists in developing a tensile fracture, hole to hole, thus establishing a defined perimeter line that will terminate any radial fractures produced by the last production row.
LONGITUDINAL VELOCITY: - speed of a wave front travelling parallel to the direction of propagation. Longitudinal waves travel near the surface and are sometimes referred to a Raleigh waves. In the body of the earth they are referred to as P waves or primary waves and are first arrival waves that are generated by earthquakes.
LOW DENSITY EXPLOSIVES: - explosives which have less breaking power due to their lower density; density may be decreased by loose packing, by altering the coarseness of the components, or by adding space consuming materials such as gas, woodmeal, microballoons, beads of Styrofoam or a type of expanded volcanic glass such as perlite; ANFO is a commonly used low density explosive, since it has a free-poured density of 0.85 gm/cc. High density explosives have densities typically in the range of 1.4 - 1.6 gm/cc. Detonation pressure is dependent on particle velocity, detonation velocity and explosive density, and therefore the effect of reduced density on detonation pressure simply results in reduced detonation pressure of the explosive product.
MICROBALLOONS: - plastic or glass spheres used to decrease the density of ANFO, or act as ingredients to pressure resistant explosive products. In emulsion explosive technology, microballoons are added to increase the sensitivity of the emulsion explosive. As in the case of trapped air in explosive formulations, discontinuities provided by trapped air and/or microballoons (density discontinuity) allow the formation of "hot-spots" as identified by BOWDEN and YOFFE as propagation centres which allow the continued propagation of the detonation head.    Microballoons can be made in different strengths (dependent on wall thickness of the plastic/glass spheres) and can therefore act as "protected" entrapped air which can give an explosive compound a certain degree of protection against environmental or transient produced pressures generated by adjacent detonating columns of explosive charges confined in water-saturated rock.
OVERBREAK: - another term describing backbreak. See backbreak.
PARTICLE VELOCITY: - the speed of a rock particle, acquired as a result of shock wave disturbance transmitted through rock. Particle velocity can be measured by particle velocity sensors which are self-generating voltage producing sensors that contain a permanent magnet surrounded by an induction coil. The magnet is usually fastened solidly to the seismometer case with the coil free to move up and down about the axial length of the magnet. The velocity of the induction coil and therefore the induced voltage produced is directly proportional to the particle velocity. This velocity is calibrated in terms of particle velocity, usually with the use of a "shake-table". Accelerometers can also measure particle velocity by integrating the output (acceleration) to obtain particle velocity. Similarly, displacement type transducers such as strain gages can measure particle velocity by taking the first derivative of displacement which is the characteristic measurement of these sensor types.
POISSON'S RATIO: - the absolute value of the ratio of the transverse strain to the corresponding axial (longitudinal or normal) strain in a body subjected to uniaxial loading.
POST-SPLITTING: - sometimes is used in underground blasting operations (drifting). Perimeter holes are fired simultaneously after the production holes to 'smooth' or 'clean-up' the drift. This ultimately provides a more stable tunnel wall. See cushion blasting. Post splitting is also used on surface to 'clean-up' free faces from buffer blasting operations.
PRE-SHEARING: - an alternate term for PRE-SPLITTING. A single line of holes that have predetermined spacing dependent on rock tensile strength, are drilled at the perimeter of the planned excavation. Such holes are loaded with decoupled explosive charges or with charges that are "toe-loaded" using the "AIR-DECKED" technique for perimeter blasting. Pre-shear blasting uses lower powder factors and must be designed to suit the specific rock strength characteristics. Generally pre-shear blasting is designed so that perimeter holes are loaded such that the expanding gases will split the rock and not exceed the in-situ dynamic compressive rock strength. Most pre-splitting is done with small diameter boreholes ranging from 2-4 inches, however some open pit mining operation and large quarries use standard production drill holes. There are typically three types of pre-shearing methods; - CONTINUOUS - (using continuous charges), - DISTRIBUTED - (using distributed decked charges), and AIR-DECKED - (using toe-loaded charges and a borehole plug).
PRE-SLOTTING: - another term used for PRE-SHEARING.  See also PRE-SPLITTING.
PRE-SPLITTING: - a controlled blasting technique employed before the main production blast where a row of closely spaced, lightly loaded holes is detonated so that a continuous open fracture is formed along the planned excavation limit. Special design criteria are used to define both the hole spacing from hole to hole as well as the burden distance in front of the last production row - all based on the in-situ rock strength characteristics. See also PRE-SHEARING.
RADIAL STRESS: - stress normal to the tangent to the boundary of an opening. Radial stress can expand outward as successive expanding cylinders when an explosive is detonated in a borehole. Radial stress can dynamically move out at a rate that is characteristic of the velocity of P-Waves.
RADIUS OF RUPTURE: - distance from the centre of an explosives loaded borehole to the limit of radial cracking produced by the detonating explosive charge.
RESISTING FORCE: - those forces in a system which tend to resist failure.
SCALED ACCELERATION: - acceleration multiplied by the square root of the explosive weight of a cylindrical charge; - this type of scaling is known as square root scaling. Also can be referred to as acceleration multiplied by the cube root of the explosive weight of a spherical charge - this type of scaling is known as cube root scaling.
SCALED DISTANCE: - distance from some point to a blast divided by the square root of the explosive weight of a cylindrical charge (square root scaling); distance from some point to a blast, divided by the cube root of the explosive weight of a spherical charge (cube root scaling). Scaled distance combines the effect of explosive charge weight on the geometrical dispersion of the vibration at distance. Normal charge weight is used, however more recently there has been movement toward a better method of standardization - the use of energy in terms of calories/gram. In this case PEAK PARTICLE VELOCITY would be plotted against SCALED ENERGY.
SCALING: - the removal of loose rocks from the surface of a pit wall. In underground mines, tunnels and drifts are scaled prior to installation of protective screening.
SCALLOP: - an undesirable remnant of rock remaining at the toe of a bench due to a blasting inefficiency. To eliminate this problem, higher energy products are used in the last production row of the blast, or in the buffer row, to provide the energy required for fracturing to the excavation limit.
SEISMOGRAPH: - an instrument which detects and records earth vibration (seismic) waves, (long period seismographs are used for earthquakes generated wave motion, whereas short period seismographs are used for blast monitoring).
SEMI-GELATIN: - a type of explosive that partially resembles a gelatin but is more economical. This type of dynamite is basically a "hybrid" type having properties between high density ammonia dynamites and gelatin dynamites. Semi-gelatin dynamites are cohesive and tamp well in boreholes, and are usually used in lower loading density applications, where high loading densities are not required.
SHEAR FACTOR: - the weight of explosives required to produce one square foot of pre-split surface area.
SHEAR ZONE: - a portion of a rock mass traversed by closely spaced surfaces along which shearing has occurred; rock may be crushed and brecciated.
SLABBING: - see cushion blasting.
SLASHING: - see cushion blasting.
SLURRY: - an explosive consisting of ammonium nitrate, water, thickeners, and a high energy sensitizer such as T.N.T.; has high bulk strength and good water resistance. Modern slurries contain liquid sensitizers such as MMAN (MONOMETHYAMINE NITRATE), EGMN (ETHYLENE GLYCOL MONONITRATE), and EAN (ETHYLAMINE NITRATE). Another class of slurries called NCN's do not contain any explosive sensitizers, but instead use air pockets such as those entrapped by the mixing process using aluminum particulate, or perlite, or air bubbles (microballoons) which provide reaction centers (due to adiabatic compression of the air pocket).
SMOOTH BLASTING: - see cushion blasting.
SPACING: - the distance between adjacent holes in a row of blastholes.
STEMMING: - material which is placed in boreholes on top of or around the explosive column to contain the detonation products and to improve blasting efficiency; usually sand, drill cuttings or fine crushed stone. Sometimes, stemming is also referred to as "collar" which is the amount of material required to completely fill the remaining borehole after it has been loaded with explosives. Alternate term is 'COLLAR'.
STATIC STRENGTH: - the amount of stress that a rock mass can withstand from a stationary load without failing.
STRESS: - the force per unit area as the area approaches zero acting within a body.
STRESS RELIEVING: - see pre-splitting.
SUBGRADE DRILLING: - that part of blasthole drilling in which the depth of the hole is extended past the planned surface of the underlying bench. This is done to put more pounds of explosive in the toe region in order to ensure full breakout.
TANGENTIAL STRESS: - stress parallel to the tangent to the boundary of any opening.
TECTONIC STRESS: - stress caused by deformation of the earth's crust; this stress may occur near the surface and greatly exceed the stress in the rock due to gravity.
TENSILE STRENGTH: - the amount of tensile stress that a rock can withstand without failing. There are two methods that are used to determine tensile strength - the first one involving DIRECT methods which grip the sample and apply loads parallel to the axis of the test specimen. INDIRECT methods comprise bending, hydraulic extension, diametral compression of thin discs of test samples, and other miscellaneous methods such as the diametral compression of cylinders, spheres, compression of square plates, and centrifugal methods of applying tension. One of the better known INDIRECT methods is known as the BRAZILIAN test method, in which a test specimen (thin disk) is squeezed across the diameter. For the BRAZILIAN test to be accurate and valid, failure of the disc sample should proceed with the development of a vertical crack which passes through the centre of the disc and towards the direction of the application of the load.
THERMOCHEMICAL PRESSURE: - the pressure which theoretically expands against the borehole wall producing hoop stress when the explosive is detonated, (the explosive in this case would be fully confined). It is calculated from thermochemical properties of the explosive, and is known as the useful pressure which does work on the surface area of the borehole wall. It is usually calculated to be about one-half the detonation pressure of the explosive.
TOE: - the base of a bank, bench, or slope in a quarry or open pit mine. Also known as the toe region in a borehole which must be filled with higher energy explosives so that scallops are prevented from forming due to underblasting the bench.
TRANSDUCER: - an instrument which converts an applied force into an electrical signal, the magnitude of the signal being proportional to the size of the applied force being measured.
TRIM BLASTING: - see cushion blasting.
UNDERCUT BEDDING: - a plane along which failure and sliding may occur because the slope of free face is greater than that of the bedding.
UNDERCUT JOINT: - see undercut bedding.
UNIAXIAL STRENGTH: - the strength of a rock sample under uniform compressive stress acting in one axis (direction) only.
VIBRATION SENSITIVITY: - the size of electrical signal generated by a transducer for each unit of vibration; usually expressed as
millivolts/mm/second. Typically, accelerometers have sensitivities in terms of charge/inch/second and use charge amplifiers to convert charge units to voltage.
WEDGES: - wedge-shaped blocks or rock whose boundaries are joint or fault surfaces. In open pit mines, such structures are dangerous if their boundaries are undercut by the mining process. Wedge failures in open cast mining can jeopardize safety and economics of the mine. In some instances, wedges have been pinned in place using elaborate civil engineering techniques to prevent movement.
YOUNG'S MODULUS: - the stress required to produce unit linear strain. As stress is initially applied to a rock specimen, the rock yields at a rate characteristic of a non-rigid material. As the stress level is increased, the rate of deformation decreases and becomes constant. This is due to the closing of "flaws" is the material specimen. The rate remains constant until fracturing begins to occur - this is the yield point.  If stress at this point is removed, some of the strain will be immediately recovered, some will be recovered on a time dependent basis, and some will be irrecoverable. Inelastic materials do not behave according to Hooke's Law. There are three common ways of specifying Young's Modulus when the stress-strain curve is non-linear. SECANT MODULUS: the slope from the origin to the specified point. TANGENT MODULUS: tangent line to a specified point. INITIAL MODULUS: the initial slope to the straight line data.
ADIT: - a horizontal entrance to a mine.
AIRBLAST: - an airborne shock wave resulting from the detonation of explosives. May be caused by burden movement of the release of expanding gas into the air. Airblast may or may not be audible. In open pit mining, explosive gases may expand through cracks to the free face adding additional airblast, especially in materials that are heavily seamed or bedded.
ANFO: - a mixture of ammonium and fuel oil capable of being used as an explosive and manufactured in conformity with a factory license. For oxygen balance, a mixture of about 94 percent AN and 6 percent FO is required. The energy output of the ANFO mixture is approximately 903 cal/gm with no anticaking material on the ammonium nitrate prills.    Using clay as the anticaking agent for low density ammonium nitrate prills, the energy drops about 3% to roughly 880 calories/gram. If energy output is plotted against % fuel oil, energy drop is less rapid on the fuel rich side - rather than the fuel lean side.    Energy can be increased by adding aluminum to the mixture up to values of about 15%.    Ammonium Nitrate is available in the form of porous prills having densities of 0.85 gm/cc, and non-porous prills with densities of up to 1.04 gm/cc. Crushing the prills reduces the critical diameter, so that ANFO can be used in 1.25 in. boreholes (suitable for drifting in underground mines).
BACK: - the roof or overhead surface of an underground excavation. This area is usually bolted and screened for safety purposes as well as providing extra strength.
BASE CHARGE: - the main explosive charge in a detonator's base. The base charge in most explosive detonators (blasting caps) consists of PETN - (PENTAETHRITOL TETRANITRATE).
BEDS: - layers of sedimentary rock, usually separated by a surface of discontinuity.    Rock can generally be readily separated along these planes. A good example of a layered sedimentary rock is limestone.
BLACK POWDER: - a low explosive consisting of sodium or potassium nitrate, carbon and sulphur. Black powder is seldom used today because of its low energy, poor fume quality and extreme sensitivity to sparks. It may be used for generating monument stone using very closely spaced boreholes loaded with this deflagrating material.
BLASTING AGENT: - any material or mixture consisting of a fuel and oxidizer that is intended for blasting. Typically, none of the ingredients are classified as an explosive. The finished product, as mixed and packaged for use or shipment, must not be able to be detonated by a No. 8 test blasting cap when confined.
BLOCKHOLE: - a small diameter borehole drilled at or near the centre of a boulder to allow the placement of a small charge to break the boulder. The term blockholing means breaking boulders by loading and firing small explosive charges in small-diameter boreholes. Can also be called - pop shooting.
BOOSTER: - a high velocity explosive used for the initiation of less sensitive explosives (non-cap sensitive) such as blasting agents (ANFO and slurries). A booster does not contain an initiating device but is often cap sensitive due to cores of PETN or pentolite, or other cap sensitive explosives. Can also be called primer.
BOOTLEG: - that bottom portion of a borehole that remains relatively intact after having been charged with explosive and fired. A bootleg is a likely place to contain an undetonated charge and should be considered hazardous. To try to extend it further by drilling is dangerous and normally against mining laws and regulations. Also called - butt.
BRISANCE: - the ability of an explosive to break (or shatter) rock by shock or impact due to the momentum contained in the travelling detonation wave. This is a term is not to be confused by gas pressure, - produced by the region behind the detonation head.
COLLAR PRIMING: - a method of primer placement in which the primer or booster is placed in the top or collar end of a borehole loaded with explosives.
COLUMN CHARGE: - a charge of explosives in a borehole in the form of a long continuous unbroken column. A column charge may be loaded on top of a toe load which is a more energetic explosive type placed in the bottom of a borehole.
COLUMN DEPTH: - the length of each portion of borehole filled with explosives. Also called - powder column, column height.
COMPATIBILITY: - explosives, including ammunition, are considered to be compatible if they may be stored or transported together without significantly increasing either the probability of an accident or, - for a given quantity, the magnitude of the effects of such an accident.
CONE: - a funnel-shaped excavation at the top of a raise intended to collect rock from the area above.
COUPLING: - the extent to which an explosive fills the cross-section of a borehole and is in direct contact with the wall of the hole. Bulk-loaded explosives are completely coupled; untamped cartridges are decoupled. Coupling ratio is the percentage of the cross-section of the borehole filled by the explosive column. A completely coupled borehole has coupling ratio of 100%.
COYOTE BLASTING: - a method of blasting using a number of relatively large concentrated charges of explosives placed in one or more small tunnels driven horizontally into a rock formation. The technique is used where it is impractical to drill vertically but is used relatively rarely because it requires a specific geology. Also called - coyote shooting.
CRITICAL DIAMETER: - the minimum diameter in which an explosive formulation will detonate or propagate completely. Critical diameter is strongly affected by confinement, temperature and pressure on the explosive, for stable propagation of detonation.
CROSSCUT: - a horizontal or nearly horizontal underground opening driven to intersect an ore body.
CROSSLINKER: - The ingredient added to a water gel, slurry or emulsion explosive causing it to change from a liquid to a gel. For example, nitrocellulose added to nitroglycerine produces a rubber waterproof gel-type structure. Also called - crosslinking agent.
CUSHION STICK: - a cartridge of explosive loaded into a small diameter borehole before the primed cartridge. The use of a cushion stick is generally not recommended in underground mining operations because of possible bootlegs.
CUT: - an artificial opening made in a face to provide a free face for blasting. It may be made mechanically as in coal mining or by explosives. The opening holes of a mine blast designed to provide 'relief for later holes to break toward. Two types are V-cut and burn-cut.
CUTOFF: - a type of misfire where there is a break in the path of detonation or initiation caused by extraneous interference such as flyrock or shifting ground. A frequent cause is choosing an improper delay system (delays too long for the pattern dimensions), or placing adjacent boreholes too close together specifically in highly stratified rock. When explosives are detonated in water-saturated rock, gases trying to occupy the space already taken up by water may tend to separated cartridges of explosives, thus causing misfires (if the gap is too great).
DEAD-PRESSING: - the desensitization of an explosive caused by pressurization. Tiny air bubbles, required for sensitivity (adiabatic compression of entrapped air), are literally squeezed from the explosive formulation.
DECK: - explosive charge separated from other charges in the borehole by stemming or an air cushion, or any other inert material. Some sources define deck as the stemming between explosive charges in a borehole. Also called decked charge, inert stemming, or gap.
DECK LOADING: - a method of loading boreholes in which the explosive charges, called decks or deck charges, in the same borehole are separated by stemming or an air cushion. Also called - decking.
DECOUPLING: - the use of cartridged products significantly smaller in diameter then the borehole. Decoupled charges are not normally used except in cushion blasting, smooth blasting, presplitting, and other situations where crushing of the borehole wall is undesirable.
DIP: - the angle at which a vein, structure or rock bed is inclined from the horizontal, measured at right angles to the strike.
DETONATING CORD: - flexible, long rope-like linear explosive charges comprised of a core of powdered explosive (usually PETN) enclosed and confined in textile and plastic coverings. The inner and outer casing materials are varied to provide specific physical properties such as tensile strength, abrasion resistance, chemical resistance, flexibility and knot tying. The average detonation velocity is 6400 m/sec.
DETONATOR: - detonators specially designed for the initiation of explosives. They are generally called blasting caps. They can be constructed to detonate instantaneously, or may contain a delay element. There are essentially two kinds: -nonelectric detonators which are activated by such means as shock, safety fuse, other incendiary devices or flexible detonating cord. Electric detonators are activated by an electric current. Accuracies of the timing elements in detonators (which are usually pyrotechnique) range from 1% to 10% depending on the method of delay element manufacture. Electronic caps are currently being developed, however their high cost usually prohibits them from use generally except for specialized applications that require stringent seismic limits on the weights of explosives that can be detonated/delay period. Detonators can be made for permissible applications as well as a host of other applications, such as high temperature and pressure environments.
DRAWPOINT: - a place where ore can be loaded and removed, located beneath the stoping area and using gravity for the transfer of ore to the loading place. Basically broken ore is dropped in the top of a chute and collected at the bottom (at the drawpoint).
DRIFTING: - the action of driving a horizontal or nearly horizontal underground opening using explosives. Horizontal boreholes are drilled using jacklegs or boom mounted drills, which are then loaded and shot.
DYNAMITE: - the high explosive invented by Alfred Nobel and, now generally includes any high explosive in which the sensitizer is nitroglycerin or a similar explosive oil.
EMULSION EXPLOSIVE: - a water-in-oil emulsion where the oxidizer is a supersaturated nitrate solution dispersed in the continuous oil phase, using voids or microballoons as the sensitizer. Emulsion explosives have a grease-like structure which allows bulk handling using the proper pumping equipment.
EXTRANEOUS ELECTRICITY: - electrical energy, other than actual firing current, which may be a hazard with electric blasting caps. Includes stray current, static electricity, lightning, radio frequency energy and capacitive or inductive coupling.
FINGER RAISE: - a raise for transfer of ore, usually arranged in a system of similar raises branching together to a common delivery point.
LOAD DIAMETER: - the diameter of the cartridged explosive product prior to placement in a borehole. If the load diameter is fully coupled to the borehole wall, the coupling ratio would be 100%. If bulk explosive products are used, automatically the coupling ratio would be 100% since bulk products placed in boreholes will tend to fill them and be coupled.    In the case of preshearing -when bulk products are used to fill tubes placed in the borehole, the explosive will be coupled to the tubing wall, which will not be the diameter of the borehole.
FUMES: - toxic gases (nitrous oxides and carbon monoxide) produced by all explosives.
GRAINS: - a system of weight measurement in which 7000 grains equal 1 pound (.45 kg).
HANGING WALL: - the wall or rock on the upper or top side of a vein or ore deposit.
HIGH EXPLOSIVE: - explosives which are characterized by a very high rate of reaction, high pressure development, and the presence of a detonation wave in the explosive. A high explosive detonates and generates a shock wave which travels at a velocity faster than the speed of sound of the explosive material
HOT SPOT: - a small localized region in an explosive substance which is characterized by a temperature much higher than that of its surroundings. Hot spots are formed by adiabatic compression of localized air pockets when hit by explosive generated shocks such as those produced by primers/boosters and/or blasting caps. These reaction centers, continue to propagate the reaction. Hot spots can also be generated by friction of particles within the explosive mixture.
HYDROSCOPICITY: - the affinity of an explosive to absorb moisture from the air. ANFO is hydroscopic because it picks up moisture from the air/surroundings. This can lead to degradation in performance since ANFO can only absorb about 2% water before it starts to deteriorate.
IGNITER CORD: - a cord-like fuse filled with thermite that burns progressively along its length with an external flame. It is used for lighting a series of safety fuses in sequence.
LEVEL: - a system of horizontal underground workings, connected to a shaft which provides access to surface. A level can also be defined as the basis of operations for excavation of ore above or below.
LIFTERS: - the bottom holes in a tunnel or drift round.
LIQUOR: - a generic name to denote a liquid mixture of explosive ingredients or non-explosive ingredients in a water solution. Hot AN/SN solutions (Ammonium Nitrate/Sodium Nitrate) are called liquors.
LOW EXPLOSIVE: - an explosive, which, when used in its normal manner deflagrates rather than detonates. For deflagrating materials, the rate of advance of the reaction zone into the unreacted material is less than the velocity of sound in the unreacted material. Low explosives can include propellants, certain primer mixtures, black powder, and delay compositions.
MISFIRE: - a charge or part of a charge which for one of any number of reasons has not exploded. They are usually difficult and dangerous to resolve. Misfires must be treated with respect. Some regulations state that up to 1/2 hour should be the waiting period before any attempt is made to investigate why a particular misfire occurred.
MUDCAPPING: - a method of blasting a boulder without drilling a hole. The charge is placed in a depression on the boulder and covered with a quantity of mud, wet earth or similar substance to confine it. Also referred to as an Adobe, Bulldoze, Blister or Plaster shot.
NITROCARBONITRATE (NCN): - NCN was a classification once given to a blasting agent by the U.S. Department of Transportation for shipping purposes. The term was never officially adopted in CANADA (except by the CTC for rail shipments under reciprocity agreements with the U.S.) and is now obsolete in the U.S. and has been replaced by "blasting agent". However, NCN may still be found as part of some product names.
NITROCELLULOSE: - substances produced by nitrating cellulose (wood or cotton).
NITROGEN OXIDES: - poisonous gases created by detonating explosives with the general chemical formula of NOx. Excessive nitrogen oxides may be caused by an excessive amount of oxygen (oxidizer) in the explosive or by an inefficient detonation reaction. Water erosion of gel type structures as well as ANFO based products can lead to the production of Nitrogen Oxides.
NITROGLYCERINE (NG): - the highly explosive oil which is a sensitizing and energy ingredient in most dynamites represented by the formula C3H5(ON02)3. For many years NG has meant a blend of nitroglycerine and ethylene glycol dinitrate which makes dynamite more difficult to freeze.
OVERBURDEN: - the material lying on top of the rock to be shot; usually refers to dirt, gravel, sand, etc. but can mean another type of rock, such as, shale over limestone.
OVERSHOT: - an adverse condition resulting from more than the necessary amount of explosives and is usually characterized by excesses of fragmentation, flyrock and noise. Generally, blast conditions can be defined by undershooting - where the cracking is less than borehole to borehole; overshooting - where cracking is greater than borehole to borehole; preshearing - where cracking is half-way to the next borehole. Typically blasting and resulting fragmentation is optimized when cracking extends from borehole to borehole.
OXIDIZER: - a chemical ingredient in an explosive which supplies oxygen to release the energy from fuel ingredients by chemical combination by combining with the fuel to form gaseous or solid products. Ammonium nitrate is the most common oxidizer used in commercial explosives.
OXYGEN BALANCE: - the theoretical percentage of oxygen in an explosive or its ingredients needed to produce ideal reaction products (carbon dioxide, water vapour and free nitrogen). A mixture containing excess oxygen has a positive oxygen balance. One with excess fuel has a negative oxygen balance. In underground mines, because of ventilation constraints, explosive designed for this application must be oxygen balanced so that no noxious fumes are produced that are hazardous to the underground working environment.
PENTOLITE: - a mixture of PETN and TNT which, when cast from the molten state, is used as a cast booster.
PERMITTED EXPLOSIVE: - an explosive which has successfully passed certain recognized standard tests and been classed as safe for blasting in gassy or dusty mines (generally coal mines) provided it is used in a standard or 'permitted' manner. Permitted explosives are designed to produce flame of the least volume, lowest temperature and shortest possible duration by the addition of certain salts. The Explosives Branch periodically publishes a list of permitted explosives which are authorized and approved for use in underground coal mines. In the U.S. the term 'permissible explosives’ is used.
PETN (PENTAERYTHRITOLTETRANITRATE): - an explosive compound used as a core load of detonating cord and the base charge of detonators.
PRILLS: - cellular particles of AN formed by spraying concentrated AN solution against a stream of air. In blasting, prills are small porous spheres of AN capable of absorbing more than 6% by weight of fuel oil. Blasting prills have a bulk density of 800 to 850 kg/cubic metres. Prills can come from long prilling towers which provide low density material or short cooling towers which can produce high density prills. Normal density or porous prills have densities ranging from .7 to .86 gm/cc whereas high density or non-porous prills can have densities up to 1.04 gm/cc.
PRIMER: - a unit, package or cartridge of cap-sensitive explosive used to initiate other explosives or blasting agents and which can provide specially designed tunnels that accept electric or nonelectric detonators as well as cords.
PROPAGATION: - the passage of a detonation wave through a column of high explosive travelling at the velocity characteristic of the explosive formulation. Propagation can also refer to the instantaneous initiation of adjacent explosive substances contained in boreholes that are too close together. Propagation can bypass the intended delay times for firing adjacent explosives loaded into boreholes drilled too close together, thus producing excessive vibration levels as well as poor fragmentation due to insufficient burden relief.
RADIO FREQUENCY ENERGY: - the energy transferred by an electromagnetic wave in the radio frequency spectrum. Under certain conditions, this energy might fire an electric detonator. I ME Pamphlet No 20 and CSA Standard Z65-1966 recommend safe distances from transmitters to electric detonators. Also called - RF energy.
RADIO FREQUENCY HAZARD: - the potential danger of accidental initiation of an electro-explosive device (EED) by radio frequency energy. Also called RF hazard, RADHAZ.
RAISE: - an underground opening driven upward from one level to another.
RAMP: - an inclined underground opening connecting levels or production areas, with an inclination allowing passage of motorized vehicles. It is usually driven downwards.
RELATIVE BULK STRENGTH: - the real strength of any volume of the explosive compared with the strength of the same volume of straight NG dynamite, blasting gelatin or ANFO, taken as 100 percent. Also called - cartridge strength, volume strength. Commercial explosives are usually compared to the ANFO standard which is taken as 100.
RELATIVE WEIGHT STRENGTH: - the real strength of any weight of explosive compared with the strength of the same weight of straight NG dynamite, blasting gelatin or ANFO, where ANFO is taken as 100 percent. 'Strength' figures can be calculated from the deflections obtained by the detonation of standard explosive charges in a freely suspended ballistic mortar or by computer analysis using thermohydrodynamic equations of state. Most current commercial explosives today are rated against ANFO.
RELIEF: - the effective distance (path of least resistance) from a borehole to the nearest free face.
ROUND: - a group or set of blastholes required to produce a specific rate of advance in underground headings or tunnels.
SAFETY FUSE: - a core of potassium nitrate black powder, enclosed in a covering of textile and waterproofing. This product is used to initiate a blasting cap or a black powder charge.
SECONDARY BLASTING: - the technique of using explosives to break up larger masses of rock resulting from primary blasts where the rocks (ore or waste) are too large for the available excavating and crushing equipment, located at/in the mine.
SENSITIVENESS: - a measure of an explosive formulation ability to propagate a detonation reaction.
SENSITIVITY: - a measure of an explosive formulation susceptibility to detonation upon receiving an external impulse such as impact, shock, flame or friction.
SENSITIZER: - an ingredient used in explosive compounds to promote a measure of increased sensitivity to an explosive formulation which assists in initiation or propagation of the detonating reaction.
SHAPED CHARGE: - an explosive with a shaped cavity, specifically designed to produce a high velocity cutting or piercing jet of product reaction; usually lined with metal to create a jet of molten linear material.
SHAFT: - a vertical or inclined underground opening through which a mine is worked. A shift provides access to the underground drifts and stopes, using a method of conveyance called a 'cage'. Ore is transported to the surface using ore carriers called 'skips' which are also located in the shaft.
SHOCK TUBE SYSTEM: - a device for initiating detonators in which the energy is transmitted to the detonator by means of a shock wave inside a hollow plastic tube. The NONEL system is such a device.
SHUNT: - the shorting together of the free ends of electric detonator leg wires or the wire ends of an electric blasting circuit. Can also refer to the name of an electrical shorting device applied to the free ends of electric wires or devices by the manufacturer.    To shunt can also mean - to short. Also called - short.
SLOT: - a vertical or inclined ore section excavated to open up for further stoping.
SPIT: - the flame produced when the safety fuse explosive composition is exposed, - at the end of the device or where notches have been made along safety fuse length to make a splitter.
SQUIB: - a small explosive device, similar in appearance to a detonator, but loaded with low explosive, so that its output is primarily heat (flash). Usually electrically initiated, it is designed to initiate action of pyrotechnic devices or propellant explosives.
STAND-OFF: - the distance of a shaped charge from a target at the instant of detonation. There is an optimum value at which best performance is achieved.
STATIC ELECTRICITY: - electrical energy stored on a person or object in a manner similar to that of a capacitor. It is most often produced by the contact and separation of dissimilar insulating materials.  It may be discharged into electrical initiators, thereby setting them off.
STOPE: - an underground excavation made by excavating ore.
STRAY CURRENT: - current flowing outside its normal conductor. Stray currents may be checked for with a blasting multimeter. Stray currents are generally man made, e.g.    shorts to ground from transformers, blowers or air lines. The minimum firing current for commercial electric detonators is 0.25A and the recommended firing current is in the 1.5 - 2.OA range. When using commercial electric detonators, the IME has established a maximum allowable stray current of 0.05A (i.e. a safety factor of five compared to the minimum firing current.
STEADY STATE VELOCITY: - the characteristic velocity at which a specific explosive, under specific conditions such as temperature and pressure, will detonate in a given charge diameter. This velocity is diameter dependent, and should not be confused with the ideal detonation velocity, which can also be steady state.
STRIKE: - the main horizontal course or direction of a mineral deposit.
SUBDRILLING: - the practice of drilling boreholes below floor level or working elevation to ensure breakage of rock to working elevation.
SYMPATHETIC DETONATION: - the detonation of an explosive as the result of receiving an impulse from another detonation through air, earth, or water. The term has occasionally been used in connection with accidents.
TAMPING: - the process of compressing the stemming or explosive in a blasthole. By slitting and tamping explosive cartridges as they are loaded in boreholes, the effective loading densities can be increased above those obtained by string loading.
TAMPING POLE: - a pole made of non-sparking material used to push explosive cartridges into a borehole and to break and tightly pack the explosives cartridges into the holes. May also be scaled in feet or metres for measuring. For safety purposes, tamping should always be done lightly, never forcefully, since all explosives are sensitive to some degree regarding impact and friction. Cartridges should be slit with the proper non-sparking knife, prior to tamping. Tamping poles should never be used as 'battering rams' forcing explosive to deform violently. Always use caution.
TRINITROTOLUENE (TNT): - an explosive compound used industrially as a sensitizer for slurries and as an ingredient in pentolite.
TRUNKLINE: - a detonating cord line used to connect the downlines or other detonating cord lines in a blast pattern. Usually runs between rows of boreholes. Delay elements can also be tied into trunkline to provide delay times between holes as well as rows.
VELOCITY OF DETONATION (VOD): - a measure of the rate at which the detonating wave front travels through an explosive charge; the speed of detonation of an explosive. The detonation wave front is a region that is highly ionized and has a density equal to approximately 4/3 the density of the unreacted explosive material itself. The rate at which this front travels can be optically determined using a high-speed rotating drum or mirror camera to obtain a 'streak' photograph. Easier methods of measurement include ionization probes, resistance probes as well as fibre optic timing probes. The velocity of detonation has been used by explosive manufacturers as a measure of the performance of explosive products. Higher detonation velocities do not necessarily mean that the explosive product will 'out-perform' those detonating at lower velocities. The application of the explosive product to a particular blasting situation is all important.
WATERGEL: - an explosive composition consisting of oxidizing salts (AN, SN) fuels and sensitizers dissolved or dispersed in a continuous liquid phase thickened and made water resistant by the addition of gelling or cross-linking agents. Perhaps the oldest gelling agent that has been used to date is quar gum, made from the quar bean, native to India. Contrary to some opinion, water is a very important ingredient since it efficiently transfers the pressures and temperature associated with the detonation front, thus enabling the wave front to be transmitted as a shock front. Watergels are sometimes referred to as slurries.
STRESS/STRAIN FIELD: - The ensemble of stress/strain states defined at all points of an elastic solid.
STRAIN/STRESS RATE: - rate of change of strain/stress with time.
ROCK MASS: - rock as it occurs in-situ, including its structural discontinuities.
STABILITY: - the condition of a structure or a mass of material when it is able to support the applied stress for a long time without suffering any significant deformation or movement that is not reversed by the release of stress.
FINITE ELEMENT: - one of the regular geometrical shapes into which a figure is subdivided   for the purpose of numerical stress analysis.
BENDING: - process of deformation normal to the axis of an elongated structural member when a moment is applied normal to its long axis.
UNIAXIAL COMPRESSION, UNCONFINED COMPRESSION: - compression caused by the application of normal stress in a single direction.
BIAXIAL COMPRESSION: - compression caused by the application of normal stresses in two perpendicular directions.
TRIAXIAL COMPRESSION: - compression caused by the application of normal stresses in three perpendicular directions.
UNIAXIAL STATE OF STRESS: - state of stress in which two of the three principal stresses are zero.
BIAXIAL STATE OF STRESS: - state of stress in which one of the three principal stresses are zero.
TRIAXIAL STATE OF STRESS: - state of stress in which none of the three principal stresses are zero.
CONTRACTION: - linear strain associated with a decrease in length.
DILATATION, VOLUMETRIC STRAIN: - the quotient of the change in volume and the original volume of an element of material under stress.
DEFORMATION: - a change in shape or size of a solid body.
DISTORTION: - a change in shape of a solid body.
DISPLACEMENT: - a change in position of a point or particle within a material type. An excursion, either positive or negative about the equilibrium position of the point or particle.
EXTENSION: - linear strain associated with an increase in length.
PLANE STRESS/STRAIN: - a state of stress/strain in a solid body in which all stress/strain components normal to a certain plane are zero.
PRINCIPAL STRESS/STRAIN: - the stress/strain normal to one of three mutually perpendicular planes on which the shear stresses/strains at a point in a body are zero.
PURE SHEAR: - a state of strain resulting from that stress condition most easily described by a Mohr circle centered at the origin.
SIMPLE SHEAR: - shear strain in which displacements all lie in one direction and are proportional to the normal distances of the displaced points from a given reference plane.
LINEAR (NORMAL) STRAIN: - the change in length per unit of length in a given direction.
SHEAR STRAIN: - the change in shape, expressed by the relative change of the right angles at the corner of what was in the undeformed state an infinitesimally small rectangle or cube.
RESIDUAL STRAIN: - the strain in a solid associated with a state of residual stress.
PERMANENT STRAIN: - the strain remaining in a solid with respect to its initial condition after the application and removal of stress greater than the yield stress. (Commonly also called 'residual' strain).
BODY FORCE: - a force such as gravity whose effect is distributed throughout a material body by direct action on each elementary part of the body independent of the others.
EXTERNAL FORCE: - a force that acts across external surface elements or external surfaces of a material body.
NORMAL FORCE: - a force directed normal to the surface element or surface across which it acts.
SHEAR FORCE: - a force directed parallel to the surface element or surface across which it acts.
SURFACE FORCE: - any force that acts across an internal or external surface elements or surfaces in a material body, not necessarily in a direction lying in the surface.
OVERBURDEN LOAD: - the load on a horizontal surface at an underground level due to the column of material located vertically above it. The load can be obtained by multiplying density of the material times the height of the material above the underground level.
PRIMARY STATE OF STRESS: - the stress in a geological formation before it is disturbed by man-made works.
SECONDARY STATE OF STRESS: - the resulting state of stress in the rock around man-made excavations or structures.
HYDROSTATIC PRESSURE: - a state of stress in which all the principal stresses are equal (and the is no shear stress). Also pertaining to the hydrostatic pressure which water exerts at the bottom of a borehole filled with water.
RESIDUAL STRESS: - stress remaining in a solid under zero external stress after some process (usually overcoring) that causes the dimensions of the various parts of the solid to change under this zero stress condition. Some other examples are - deformation under the action of external stress when some parts of the body suffer permanent strain, and - heating or cooling of a body in which the thermal expansion coefficient is not uniform throughout the body.
COMPRESSIVE STRESS: - normal stress tending to shorten the body in the direction in which it acts.
SHEAR STRESS: - stress directed parallel to the surface element across which it acts.
TENSILE STRESS: - normal stress tending to lengthen the body in the direction in which it acts.
ATTENUATION: - reduction in the amplitude of a wave with the distance of propagation from its source. In blast monitoring using seismic transducers that measure peak particle velocity, attenuation curves are generated by firing different charge weights at fixed distances to obtained attenuation curves which characterize the seismic wave transmission characteristics of the monitored area. These curves can then be used to predict the particle velocity for specific charge weight with some statistical accuracy.
DAMPING: - reduction in the amplitude of vibration of a body or system due to dissipation of energy internally or by radiation.
RISE TIME: - the interval of time required for the leading edge of a pulse to rise from some specified small fraction to some specified larger fraction of the maximum value.
DECAY TIME: - the interval of time required for a pulse to decay from its maximum value to some specified fraction of that value.
DISPERSION: - the phenomenon of varying speed of transmission of waves, depending on their frequency. Because of the frequency changes generated, amplitudes generally decrease as wave fronts are dispersed away from their source.
NATURAL FREQUENCY: - the frequency at which a body or system vibrates when unconstrained by external forces.
MICROSEISM: - seismic pulses of short duration and low amplitude often occurring previous to failure of a material or structure. Microseismic instrumentation is sensitive enough to pick up noise generated by such microseisms in rock which may undergo movement due to slippage along a fault.
SEISMIC VELOCITY: - the velocity of seismic waves in geological formations.
LONGITUDINAL WAVE: - a wave in which the displacement at each point of the medium is normal to the wave front.
TRANSVERSE/SHEAR WAVE: - a wave in which the displacement at each point of the medium is parallel to the wave front.
SHOCK WAVE: - a wave of finite amplitude characterized by a shock front, a surface across which pressure, density and internal energy rise almost discontinuously. Such a wave travels with a speed greater than the normal speed of sound of the specific material type. In explosive detonation theory, a shock wave is characterized as a supersonic condition such the wave front is reinforced and fed by the chemical reaction preceding it.
SURFACE WAVE: - a wave confined to a thin layer at the surface of a body.
WAVEFRONT: - a continuous surface over which the phase of a wave that progresses in three dimensions is constant. Also can be defined as a continuous line along which the plane of a surface wave is constant.
INELASTIC DEFORMATION: - the portion of deformation under stress that is does not result in permanent deformation when the application of stress is removed.
YIELD STRESS: - the stress beyond which the induced deformation is not fully recoverable after complete destressing.
INTACT ROCK: - material of the rock mass typically represented by whole drill core which does not break apart and is not affected by gross structural discontinues.
SHEAR PLANE: - a plane along which failure of material occurs by shearing.
COHESION: - shear resistance at zero normal stress. An equivalent term in rock mechanics is intrinsic shear strength.
CREEP: - time dependent deformation.
DILATANCY: - property of volume increase under loading.
DUCTILITY: - a condition in which material can sustain permanent deformation without losing its ability to resist load.
ELASTICITY: - a property of material which permits it to return to its original form or condition after applied force is removed.
ELASTIC LIMIT: - a point on the stress/strain curve at which transition from elastic to inelastic behaviour takes place.
FATIGUE: - decrease in strength of a material type by repetitive loading.
FATIGUE LIMIT: - point on stress/strain curve below which no fatigue can be obtained regardless of number of loading cycles.
HARDNESS: - resistance of a material to indentation or scratching.
STIFFNESS: - can be defined as force-displacement ratio.
HOMOGENEITY: - having the same properties at all points.
HETEROGENEITY: - having different properties at different points.
HYSTERESIS: - incomplete in recovery of strain during unloading cycle due to internal energy consumption or absorption.
ISOTROPY: - having same properties in all directions.
ANISOTROPY: - having different properties in different directions.
MODULUS OF ELASTICITY (YOUNG'S MODULUS): - the ratio of stress to corresponding strain below the proportional limit of a material.
MODULUS OF DEFORMATION: - the ratio of stress to corresponding strain during loading of a material/rock sample and including elastic and inelastic behaviour.
SECANT MODULUS: - slope of the line connecting the origin and a given point (not tangent - but on the secant) on the stress/strain curve.
TANGENT MODULUS: - slope of the tangent to the stress/strain curve at a given stress value (generally taken at a stress equal to one-half the compressive strength).
UNLOADING MODULUS: - slope of the tangent to the unloading stress-strain curve at a given stress value.
BULK MODULUS: - the ratio of hydrostatic pressure to the volumetric strain which it produces.
PLASTICITY: - property of a material to continue to deform indefinitely while sustaining a constant stress or load.
VISCOELASTICITY: - property of materials which experience strain under specific loading conditions such that they deform partly elastically, and partly viscously. Also whose strain is partly dependent on time and magnitude of stress.
STRESS RELAXATION: - stress release due to creep.
RETARDATION: - delay in deformation.
THIXOTROPY: - the property of liquefying on being shaken and then being able to reform back to original state after standing.
WEATHERING: - the process of disintegration and decomposition as a consequence of exposure to the atmosphere, to chemical action and to the action of frost, water and heat.
FAILURE: - failure in rocks means exceeding of maximum strength of the rock, -or exceeding the stress or strain requirement of a specific design.
FAILURE CRITERION: - theoretically or empirically derived stress or strain relationships characterizing the occurrence of failure in the rock.
PROGRESSIVE FAILURE: - formation and development of localized fractures which, after additional stress increases, eventually form a continuous rupture surface and can lead to failure after steady and progressive deterioration of a material or rock sample.
BRITTLE FRACTURE: - sudden failure with complete loss of cohesion across a plane.
FRACTURE PATTERN: - a spatial arrangement of a group of fracture surfaces.
DISKING: - breakage of a hard rock core into disks during diamond drilling, - caused by high field stresses.
PLANE OF WEAKNESS: - a surface or narrow zone with a shear or tensile strength lower than that of the surrounding material.
ROCK BURST: - sudden explosive-like release of energy due to the failure of a brittle rock of high strength.
SLIDING: - relative displacement of two bodies along a surface, - without loss of contact between the bodies.
SPALLING: - longitudinal splitting in uniaxial compression. Also the breaking-off of plate-like pieces from a free rock surface. In crater using explosives, tensile failure in terms of spalling occurs at a free surface if the reflected compressive wave (tensile) has a value that is greater than the tensile strength of the rock.
BUCKLING: - instability of a column or a plate under a sufficient high failing for any given type of loading.
STRENGTH: - maximum stress which a material can resist without failing for any specific type of loading.
SIZE EFFECT: - influence of specimen size on its strength or other mechanical parameters.
PEAK SHEAR STRENGTH: - the maximum shear strength along a failure surface.
RESIDUAL SHEAR STRENGTH: - shear strength along a failure surface after a large displacement.
DISCONTINUITY SURFACE: - any surface across which a specific property for a rock mass is discontinuous. This includes fracture surfaces, weakness planes, and bedding planes but the term should not be restricted only to mechanical continuities.
FISSURE: - a gapped fracture.
RUPTURE: - that stage in the development of a fracture where instability occurs. This term should not be used in rock mechanics as a synonym for fracture.
CRACK: - a small fracture; i.e. small with respect to the scale of the feature in which it occurs.
BEDDING: - applies to rocks resulting from consolidation of sediments and exhibiting surfaces of separation (bedding planes) between layers of the same or different materials, e.g. - shale, siltstone, sandstone, limestone, etc.
THICKNESS: - the perpendicular distance between bounding surfaces such as bedding or foliation planes of a rock.
BEDROCK: - the more or less continuous body of rock which underlies the overburden soils.
TEXTURE: - the arrangement in space of the components of a rock body and of the boundaries between these components.
FABRIC: - the orientation in space of the elements composing the rock substance.
STRUCTURE: - one of the larger features of a rock mass, like bedding, foliation, jointing, cleavage or brecciation; also the sum total of such features as contrasted with texture.    Also, in a broader sense, it refers to the structural features of an area such as anticlines or synclines.
SCHISTOSITY: - the variety of foliation that occurs in the coarser grained metamorphic rocks and is generally the result of the parallel arrangement of platy and ellipsoidal mineral grains within the rock substance.
LINEATION: - the parallel orientation of structural features that are lines rather than planes. Some examples are parallel orientation of the long dimensions of minerals; long axes of pebbles; striae on slickensides; and cleavage-bedding plane intersections.
CLEAVAGE: - the tendency to cleave or split along definite parallel planes, which may be highly inclined to the bedding. It is a secondary structure and is ordinarily accompanied by at least some recrystallization of the rock.
SUBSIDENCE: - the downward displacement of the surface rock and/or soil lying above an underground excavation or adjoining a surface excavation. Also - the sinking of a part of the earth's crust.
KARST: - a geologic condition where cavities are developed in massive limestone beds in which limestone itself is dissolved by flowing water. Caves and even underground river channels are produced into surface runoff drains, which often result in the land above being dry and relatively barren.
LANDSLIDE: - a dramatic downward sliding or movement of a mass of earth, rock or mixture of both.
FILLING: - generally the material occupying the space between fracture surfaces, in joints, faults, and other rock discontinuities. The filling material may be clay, gouge, various natural cementing agents or alteration products of the adjacent rock.
JOINT/FAULT SET: - a group of more or less parallel joints/faults.
JOINT/FAULT SYSTEM: - consists of two or more joint/fault sets or any group of joints/faults with a characteristic pattern, e.g., radiating, concentric, etc.
JOINT PATTERN: - a group of joints which form a characteristic geometrical relationship, and which can vary considerably from one location to another within the same geologic formation.
JOINT DIAGRAM: - a diagram constructed by accurately plotting the strike and dip of joints to illustrate the geometrical relationship of the joints within a specified area of geologic investigation.
CONJUGATE JOINTS/FAULTS: - two sets of joints/faults that formed under the same stress conditions (usually shear pairs).
FAULT BRECCIA: - a conglomeration of broken rock fragments frequently found along faults. The fragments may vary in size from inches to feet.
FAULT GOUGE: - a clay-like material occurring between the walls of a fault as a result of the movement along the fault surfaces.
FOLD: - a bend in the strata or other planar structure within the rock mass.
PERMEABILITY: - the capacity of a rock to conduct liquid or gas.  It is measured as the proportionality constant, k, between flow velocity, v, and hydraulic gradient, i. By definition - v = k.i
HYDRAULIC GRADIENT: - the change of pressure head per unit of distance at a given point and in a given direction.
MOISTURE CONTENT: - the percentage by weight of water contained in the pore space of a rock or soil with respect to the weight of the solid material.
DEGREE OF SATURATION: - the extent or degree to which the voids in rock contain fluid (water, gas or oil). Usually expressed in percent related to total void or pore space.
PERCOLATION: - the movement, under hydrostatic pressure, of water through the smaller interstices or rock or soil, excluding movement through large openings such as caves and solution channels.
POROSITY: - the ratio of the aggregate volume of voids or interstices in a rock solid to its total volume.
PNEUMATIC LOADER: - a method of loading prilled ANFO using high pressure air (about 60-100 psi) in conjunction with a suitable hopper and anti-static air hose. The ANFO prills are broken down in the process and are packed to higher densities of up to 1.0 gm/cc which is higher than the regular porous prilled ANFO density of 0.85 gm/cc. Because prills are broken down, this reduces the critical diameter of the ANFO product so that drift rounds using 1.25 in. diameter boreholes can be used. Cartridge loaders allow faster loading rates as well as increased compaction because of the effect of air pressure which effectively tamps the cartridges after being slit by a small tack placed at the hose outlet. Such loaders must be cleaned regularly to ensure safety and the prevention of fouling critical parts.
METRIC CONVERSION: - the metric system originated in France when Gabriel Mouton first proposed a decimal system having as a basis a measurement of the earth. He also proposed Latin prefixes for multiples and submultiples of units. The French revolution in 1789 provided the opportunity. The unit of length in the new system, the meter (Gr. Metron) was to be equal to a ten-millionth part of the quarter meridian (North Pole to equator), passing through Paris. Some part of the meter, cubed, was to be the capacity standard which, when filled with water, would provide a standard mass. The hope was to interrelate the units for three quantities: length, capacity and mass in order to simplify the various computations and conversions necessary in using a weights and measures system. The quarter-meridian has to be accurately measured. Two engineers were assigned and surveyed from Barcelona, Spain in the South, and to Dunkirk in the North. Prefixes are used to indicate decimal fractions of mulitiples of a unit; e.g. - deci(liter) = 0.1 liter, also deka(liter) = 10 liters.
ABSOLUTE VALUE: - in mathematics a plus sign (+) is used to indicate positive values and a negative sign (-) is used to indicate negative values. They also indicate addition or subtraction respectively. If no sign appears beside a number or variable, the + is understood. Taking the absolute value of a number means converting the number so that it is positive even though it may be negative. For example, the absolute value of + 5 is + 5, whereas for - 10, the absolute value would be + 10.
SF: - a term used in BLASTCALC to define the Y-intercept of a regression line usually determined using regression analysis for plotting the best fit line of seismic data. The Y-intercept is a particle velocity number in this case, however it may also refer to any unit system on the Y-axis of a graph.
SS: - a term in BLASTCALC used to define the slope of the regression line using the vibration interpolation calculator or some other method using non-linear least squares fit techniques. Normally this value is negative indicating a negative slope (meaning that particle velocity is attenuated with increasing distance away from detonating charges).  In BLASTCALC, this number must be entered as a positive number since the negative prefix is stored within the BLASTCALC program.
INTERPOLATION: - a procedure which requires estimating the values of a function f(x) for arguments between x0,....xn at which the values y0,....yn are known. For example, in blast monitoring, if a seismograph can read peak particle velocities at specific distances away from detonating charges of explosives, a non-linear regression analysis of the data can produce a line that can be fit along the data to describe the attenuation of particle velocity with increasing distance from the explosive charges. Here, y values represent peak particle velocity, whereas x values represent scaled distance (distance/square root of charge weight).
REGRESSION CURVE: - using simple data, the estimated value of a variable y corresponding to a given variable x can be found by estimating the value of y from a least square curve which fits the sample data. The resulting curve is called a regression curve of y on x, since y is estimated from x. For linear data, a linear (straight line fit) regression fit can be found. For non-linear data, a non-linear (geometric, parabolic, hyperbolic, or power fit) regression fit can be obtained.
POWDER FACTOR: - a term that gives the ratio of the amount of explosive product loaded, and the amount of broken rock produced. Powder Factor is usually expressed in terms of pounds/ton of broken rock, or pounds/cubic yard of broken rock. Sometimes the reciprocals of these terms are used.
LOAD DENSITY: - a term in BLASTCALC which describes the explosive density (load) in terms of specific gravity (SG).
DECOUPLED HEIGHT: - a term in BLASTCALC which describes the column height of decoupled cartridges loaded into boreholes whose diameter is larger than the explosive load diameter.
COUPLED HEIGHT: - a term in BLASTCALC which describes the column height of coupled charges of explosive load. In this case, the resulting explosive load diameter would be equal to the borehole diameter. The explosive load, therefore, would be 100% coupled to the borehole wall.
DECOUPLED STEM LEFT: - a term in BLASTCALC which describes the amount of collar/stemming left after decoupled explosive loads have been used in a borehole which has a larger diameter than the explosive load.
COUPLED STEM LEFT: - a term in BLASTCALC which describes the amount of collar/stemming left after fully coupled explosive loads have been used to fill a borehole. The explosive load is fully coupled to the borehole wall. This is opposite to decoupled stem left where explosive loads are decoupled from the borehole wall.
STEMMING LEFT: - a term in BLASTCALC which denotes the amount of collar/stemming remaining in the borehole. This is a measure of the vertical height than remains to be stemmed.
COLUMN HEIGHT: - a term in BLASTCALC which denotes the vertical height of explosive that is to be loaded, or that is already loaded into a borehole.
CASE WEIGHT: - a term in BLASTCALC which denotes the weight of a single case of explosive product in terms of pounds. Also the packaged case weight.
CARTRIDGE CASE COUNT: - a term in BLAST CALC which gives the number of cartridges of explosives having a specific density and diameter, that will fit within a case/box that will hold a specific weight of explosive product.
CARTRIDGE DIAMETER: - a term in BLASTCALC that denotes the packaged diameter of a specific explosive product.
CARTRIDGE LENGTH: - a term in BLASTCALC that denotes the specified packaged cartridge length of an explosive product. The packaged cartridge length.
CARTRIDGES LOADED: - the number of cartridges loaded into a borehole having a specific diameter, - a term used in BLASTCALC.
MAX CARTRIDGES (COUPLED): - a term used in BLASTCALC which is used to estimate the total number of fully coupled cartridges that are required to completely fill a borehole without any collar/stemming. The borehole is simply filled to the top with coupled explosive cartridges. This is a useful calculation since it provides the exact number of cartridges required to fill a borehole drilled to any depth at any diameter. The user can then choose the number of cartridges desired.
WEIGHT LOADED: - a term used in BLASTCALC to denote the weight of an explosive product in a borehole of a specific diameter drilled to a specific depth.
STEM LEFT: - a term used in BLASTCALC which is the same as stemming left. See STEMMING LEFT definition.
TIMING: - a term used in BLASTCALC to denote the time delay value of an explosive charge loaded in a borehole. It is the cap delay time for the explosive load contained in the borehole. It is also the time when the explosive load will be detonated.
LEFT-TO-LOAD: - a term used in BLASTCALC which estimates the amount of borehole left to load. Similar to collar/stemming left.
LOAD PRIMER NAME: - a term used in BLASTCALC to denote the trade name of the primer used to initiate a particular explosive product.
CONTINUOUS LOAD: - a term used in BLASTCALC to describe an explosive product which is manufactured in long length of charge. Usually this type of explosive is packaged in flexible plastic or valeron tubing and is coiled up inside its packing case as a roll.    This type of explosive product is very handy for loading in long boreholes where it is used as a decoupled charge for pre-shearing applications (it comes in one unit lengths depending on the diameter).
PATTERN SPACING: - a term used in BLASTCALC which is the spacing distance between boreholes used in a particular pattern - square, rectangular, staggered, dice, etc.). The spacing is normally equal to or greater than the burden distance.
PATTERN BURDEN: - a term used in BLASTCALC which denotes the burden distance in a particular pattern - (square, rectangular, staggered, dice, etc.). The burden is normally less than the spacing distance. The burden distance direction is normally at right angles to the free face, whereas the spacing distance direction is parallel to the free face (if only one free face is present).
OUT-OF-WATER: - a term in BLASTCALC which estimates the distance from the bottom of a wet borehole to the top of the water column after decoupled cartridges of explosive have been loaded. It implies that the rest of the borehole would be dry and suitable for loading non-water resistance explosive (such as ANFO) on top of the previously loaded cartridges.
TOTAL VOLUME: - a term used in BLASTCALC that gives the total volume of rock contained by a blasting pattern that has a specific burden, spacing and borehole depth including any subdrill.
PAY VOLUME: - a term used in BLASTCALC that gives the volume of rock contained by a blasting pattern having a specific burden, spacing and borehole depth -not including any subdrill.    Basically it is the volume of rock for which blasting contractors receive payment.
TOTAL PF: - total powder factor; a term in BLASTCALC which is a ratio of total explosives used to break either a ton or cubic yard of rock. The weight/volume of rock broken depends on the total borehole depth including any subdrill. Assumes that the explosives load is completely coupled to the borehole wall.
PAY PF: - pay powder factor; - a term in BLASTCALC which is a ratio of total explosives used to break either a ton or cubic yard of rock. The weight/volume of rock broken depends on the total borehole depth MINUS any subdrill. Assumes that the explosives load is completely coupled to the borehole wall.
COUPLED PF: - coupled powder factor; a term in BLASTCALC which is a ratio of total explosives used to break either a ton or cubic yard of rock. The weight/volume of rock broken depends on the total borehole depth including any subdrill. Coupled powder factor differs from both total and pay powder factor since it includes the effect of charge decoupling whereas the other two terms do not.
PAY COST: - pay cost ($/cu yd or $/ton) is a BLASTCALC term in which the total explosives cost based on pattern burden, spacing, and borehole depth INCLUDING the subdrill.
IDEAL VELOCITY: - a term used in BLASTCALC to denote the maximum velocity a particular explosive formulation can generate and is totally dependent on that specific formulation. To get the ideal detonation velocity of a particular explosive product, a sample of the explosive is packaged in large charge diameters, typically over 15 in., with the velocity measured. Whereas this is a practical way of getting the ideal velocity, some computer programs are available that use thermohydrodynamic code to arrive at the ideal or the D* velocity. (D* is a contraction for ideal velocity).
CRITICAL VELOCITY: - a term used in BLASTCALC to denote the minimum velocity obtained by an explosive formulation such that the explosive load is able to detonate completely at this velocity. Any velocity lower than this will result in deflagrations, or die-out. The detonation reaction will not be able to support itself.
ESTIMATED VELOCITY: - a term defined by BLASTCALC as being a velocity that is estimated for a specific charge diameter of a particular explosive formulation. It is based on ideal velocity and critical velocity of that particular explosive formulation.
CORD VELOCITY: - the detonation velocity of a specific detonating cord; used by BLASTCALC.
LOAD VELOCITY: - the detonation velocity of a particular explosive product in a specific diameter of charge; used by BLASTCALC.
TRACED VELOCITY: - this is the velocity obtained when explosive products are side-initiated by detonating cord. When cord is used as a continuous primer (grain size must be sufficient to initiate), the explosive load does not detonate at the velocity of primacord, but is a vector of that velocity. The actual measured velocity in the explosive charge depends on sensitivity and run-up distance, and in some cases can be much lower that the steady-state velocity of the explosive formulation in the diameter of charge being side-initiated.
IMPULSE PRESSURE: - a term used in BLASTCALC than defines pressure-time. Basically it is the area under the detonation pressure, detonation time curve and considers primer geometry. It provides a basis for measuring primer efficiency.
PRIMER EFFICIENCY: - a term used in BLASTCALC which defines primer efficiency-based on a 2 in. diameter x 5 in. long pentolite primer having a velocity of 24,000 ft/sec. and a specific gravity of 1.7. In many situations, substitute ‘primers' such as dynamites, watergels, emulsions, etc. are used as substitute 'primers*. These are not nearly efficient as cast TNT or pentolite primers.
FRACTURE INDEX: - a term used in BLASTCALC that defines in-situ geology in terms of index. Hard rock that is fairly homogenous (few cracks/inherent faulting etc.) will have index values typically less than 50%. Softer rock with other discontinuities throughout the mass will have higher index values, typically greater than 50%.
ALUMINUM CONTENT: - the percentage of aluminum in a particular explosive formulation. Aluminum can be added as paintgrade, foil, cutting, atomized, filing stock.
TOTAL LENGTH: - a term used in BLASTCALC that describes the total length of blast measured in the spacing direction.
TOTAL WIDTH:  - a term used in BLASTCALC that describes the total blast width measured in the burden direction.
TOTAL AREA: - in BLASTCALC, the area described by total blast length and total blast width.
STRAIN ENERGY: - can be defined as the total energy stored in a body or volume of rock resulting from the strain as well as stress that exists in that body or volume of rock.    It is a form of potential energy that is theoretically available for doing work upon release of the stress.
SHEAR MODULUS: - also known as the Modulus of Rigidity. It is the ratio of shear stress to shear strain for a material and is determined either from the slope of the tangent or of the secant of a shear stress-strain curve.
MONITORING DISTANCE: - the distance between the blast centre or closest borehole to a seismic station comprising a seismometer that measures particle velocity, acceleration, or displacement.
COMPRESSIBILITY: - can be defined as either linear or volumetric. Volumetric compressibility is the inverse of bulk modulus. It is a positive value and has dimensions which are the reciprocal of pressure. Compressibility can be determined directly as a volume change under specific pressure or can be determined from changes in linear dimensions under specific pressure.
STRESS VALUE: - in underground mining, it is important that stress levels due to blasting be kept at minimum values to avoid tensile scabbing/spalling at the boundaries of tunnel walls and drifts. Peak particle velocity measured at the tunnel wall or roof in conjunction with mass density and P wave velocity of the rock type can be used to calculate the stress value for a specific particle velocity as measured by accelerometers or seismic particle velocity sensors. Limits on charge weight detonated/delay can be used to set peak particle velocity limits and hence stress values so that rock competence around underground openings is not compromised.
RIB: - a term used in coal mining which defines the solid coal on the side of a gallery or long wall face, basically a pillar of coal left for support. In hard rock mining, it is an elongated pillar which has been left to support the hanging wall.
POISSON'S EFFECT: - a term which describes the lateral deformation resulting from longitudinal stress.
OVERCORING: - a technique which is used to define the in-situ value of strain in which a large diamond bit is used to overcore a smaller borehole which has been instrumented with strain gages. Once the core is removed or detached from the host rock, the confining influence has been removed, resulting in a slight expansion of the core. The difference in strain when the core was intact with the rock mass and its removal from the constraint of the rock mass, provides a measure of the confining strain. Because of the small displacements involved, many readings must be taken for the measurement to be statistically valid.
OVERPRESSURE: - the pressure in an air blast wave which is in excess of atmospheric pressure.
LONGWALL: - a mining technique in which a seam or vein is completely taken out with no pillars left for support, except for shaft pillars, and main road pillars. Longwall advance is going forward from the shaft pillar, maintaining roadways through the workings. Longwall retreating is driving the haulage road first to the boundary of seams or veins, and then mining in a single face without pillars moving back toward the shaft.
HOOKE'S LAW: - a law in which stress is defined to be proportional to strain.
GALLERY: - in underground mining, a level or drift that normally has operating production stopes of the level or drift.
FULL FACE BLASTING: - a method of drifting such that the whole surface area of the face is blasted out with each round.
CREST: - the top of an excavated slope, or the highest point of an anticline. In open pit mining, it refers to the top of a bench.
CROWN: - an alternate term for the roof of a tunnel.
CRITICAL SLOPE: - defined as the maximum angle with the horizontal at which a slope of specific height will stand so that it does not need to be supported.
ARCH: - defined as the curved roof of an underground opening. Also defined as a man-made structure spanning an opening that is curved so as to minimize bending stresses.
ARCHING: - the transfer of stress from a yielding part of a rock mass to an adjoining less-yielding or restrained part of the rock mass.
CLOSURE: - defined as the inward movement of the footwall and hanging wall, or of any two opposite surfaces such as opposite walls in tunnels or drifts of underground mines.
DURATION OF SHOCK: - the time required for a shock pulse or wave to rise from zero value to the maximum value and then decay to a zero value or some arbitrary level.
MASS DENSITY: - the density of a material divided by the acceleration of gravity.
EXTENSOMETER: - an instrument used to measure extremely small displacements or deformations. Usually placed in a borehole in order to measure free face movement.
FREQUENCY: - the number of cycles/second.
INERTIA: - a fundamental property which resists motion or a change of the state of rest.
LITHOLOGY: - a development of geology such that rock samples or mineral samples are cut into extremely thin sections so that they can be examined using microscopic techniques.
MODULUS OF RIGIDITY: - defined as the ratio of shear stress to shear strain and is determined from the slope of the tangent or secant of a shear stress-strain curve.
ORTHOGONAL: - to be at right angles.
PHOTOELASTICITY: - a method of determining stress distributions using optical methods.
PIEZOMETER: - a specially designed instrument for determining pressure head.
PLASTIC: - the state of a material is such that on application of stress, some of the resulting strain will not be recoverable.
PROPORTIONAL LIMIT: - defined as the greatest stress that a material is capable of developing without any deviation from HOOKE'S LAW. A material that does not violate HOOKE'S LAW, when stressed to a value for which strain is completely recoverable.
PRINCIPAL PLANE: - described as each of three mutually perpendicular planes through a point in a body on which the shearing stress is zero.
RADIUS OF GYRATION: - of an area or mass is equal to the square root of the moment of inertia divided by the area or mass.
RESPONSE: - the resulting motion of an elastic system upon excitation from an external force.
ROCKFALL: - the fall of any segment of a rock mass from its host structure. Mostly pertains to underground mines when part of the roof becomes detached and falls.
SET: - a wooden frame of heavy timber for supporting ground around a shaft or underground opening.
SPECIFIC VOLUME: - volume/unit weight of a specific material or sample.
SPECIFIC GRAVITY: - the ratio of the mass of a body to the mass of an equal volume of water at a specified temperature.
STRESS ELLIPSE: - for two dimensional analysis, the ellipse whose half-axes are the major and minor principal stresses.
TOP HEADING METHOD: - a mining method of tunneling or drifting such that the top part of the face is excavated ahead of the lower part and usually in a separate drilling and blasting operation.
VISCOSITY: - the property of liquids and solids that causes them to resist instantaneous change of shape, but produces strain that is dependent on both time and the magnitude of the applied stress.
WORK: - the product of force and the distance through which it acts.
TRANSIENT VIBRATIONS: - sinusoidal vibrations that disappear with time or that are damped out with time.
TUBBING: - a timber or metal lining for a shaft, that is usually watertight. Used in unconsolidated ground.
ULTIMATE BEARING CAPACITY: - defined as the average load per unit area required to produce failure of a supporting rock mass.
UNCONSOLIDATED: - defined as an accumulation of sediment that has not been exposed to pressures which allow compaction or cementation.
DESTRESSING: - a technique first developed in SOUTH AFRICA in very deep gold mines. Stress behind a working face of a stope can increase to a maximum at some distance behind the face and then falls off at distance. Destressing this high concentration of stress means drilling holes and loading them with explosives to shatter the 'transmission’ zone of that specific stress. High values of stress are not able to be transmitted through broken zones of rock. Stress would be virtually 'thrown back’ into the rock mass at some distance from the working face, thus removing the potential danger of outbursting. Optimum methods of positioning the holes and explosive loads depend on the rock type and structure.
EXPLOSIVE ACTION IN ROCK: - peak pressures generated are extremely high; have durations equivalent to the detonation time of a specific mass of explosive. Thermochemical pressure (work pressure) is equal to about .5 the detonation pressure. Pressures have steep risetimes. High stresses (hoop stress - radial and tangential) induced around a borehole cause rock media to compress and acquire an outward particle motion. This motion transmits stresses further into the rock mass and away from the shot point.    Longitudinal waves travel at the speed of sound in the in-situ rock mass, shear waves are slower; about .5 the longitudinal value. Cracks are formed due to hoop stresses (borehole expands to POISSONS' LIMIT), and hence high borehole pressures dissipate quickly (in milliseconds). After the removal of the blast induced compressive ground stress, rock which has not failed rebounds elastically to its original state. The short duration of blast induced ground stress limits the zone of compressed rock to a very narrow cylindrical region around the borehole wall.
CRACK VELOCITY: - crack velocities have been measured to be between ranges of 2000 fps - 8000 fps in most instances. From the critical-flaw concept of Griffith, velocity of crack propagation has been found by Mott (1948) to be dependent on the velocity of the longitudinal wave, crack length, and the critical crack size, Co, as determined from Griffith failure theory. Roberts and Wells (1954) evaluated Mott's equations further and determined that the maximum crack velocity that a material can have is approximately .5 the velocity of the shear wave in that specific material. Crack velocity can be expressed in the mathematical form; Cv=f(T,p,E,V,X) where X indicates the residual plastic energy in a specific material type. There is substantial evidence that when cracks attain velocities higher than predicted, approaching .6 that of the velocity of the shear wave, they will tend to curve. At lower velocities cracks will restrict themselves to straight line trajectories. Stresses can be superimposed at the crack tip, thus affecting velocity and trajectory.
DETONATING CORD TYPES: - cords have different core loads as follows; B-line: 25 grains/ft (.0036 pounds/ft); E-cord: 25 grains/ft (.0036 pounds/ft); PLAIN PRIMACORD:  40 grains/ft (.0057 pounds/ft); REINFORCED PRIMACORD: 50 grains/ft (.0072 pounds/ft); SCUF-FLEX: 60 grains/ft (.0086 pounds/ft); TRUNKLINE:  50 grains/ft (.0072 pounds/ft); SUPER SCUF-FLEX:  60 grains/ft (.0086 pounds/ft); BOOSTER CORD: 4.5-300 grains/ft; PRIMAFLEX: 400 grains/ft (.0571 pounds/ft).
PRIMACORD MS CONNECTOR: - a non-electric primacord based device which can be tied into primacord trunkline to create millisecond delays of predetermined duration in the primacord circuit.
BOOSTER CORD: - a 4.5 grain/ft cord with 300 grain/ft bumps approximately every 10 ft. This cord is used in underground long holes as an initiating device or primer.
NONEL: - an initiating detonator that uses a shock tube, not a core load, to provide the means of generating a shock to the initiating charge in a detonator. Completely noiseless on surface.
RESILIENCE: - sometimes called toughness or sponginess and refers to the inherent plasticity of the host material. It expresses the ability of a rock mass to resist stress and recover its original shape without rupture particularly after blasting. Permafrost is resilient.
GENERATOR BLASTING MACHINES: - a small generator which is activated by a fast hand twist or push-down plunger. Develops pulsating direct current and are designed so that no current is released into the circuit until the end of the stroke.
CONDENSER BLASTING MACHINES: - for the power source, dry cell batteries are used in conjunction with a DC-AC inverter which charges high capacity capacitors which then discharge into the electric circuit hookup.
TOP PRIMING: - a method of priming an explosive load such that the primer or blasting cap is placed near the top of the load column. Drilling boreholes closely together could result in cutoffs near the top of the explosives column. Care must be exercised because of this cutoff potential.
BOTTOM PRIMING: - a method of priming explosive loads by situating the primer or initiating device (blasting cap) near the bottom of the explosive load.
BLAST CONFINEMENT LEVEL: - a term used in BLASTCALC which designates the level of confinement of blasting according to MINIMUM - meaning almost no confinement, such as blasting to open faces - open pits/quarries; also MODERATE - meaning buffer blasting or blasting in front of a loose muck pile; also MAXIMUM - meaning sinking cuts, trench blasting, where there are no apparent open faces for bulk material movement.
CARTRIDGE DENSITY: - a term used in BLASTCALC which denotes explosive packaged density in terms of SPECIFIC GRAVITY.  See SPECIFIC GRAVITY.
SG: - a short form term for SPECIFIC GRAVITY.
INERT DECK: - usually crushed rock or drilling cuttings or fine sand which is placed between two separate column loads placed in the same borehole. By separating the column loads and firing them on different delay periods, the overall weight/delay of explosives initiated is reduced, thus lowering vibration levels. Separation of explosive loads within boreholes has obvious economic effects particularly if the rock type is considered to be weak or incompetent. Lower concentrations of charges can be used providing cost savings.
POWER (KVA): a term used in BLASTCALC to denote the amount of power required to fire a particular configuration of electric caps (series, parallel or series-parallel). The quantity of power required is given in terms of KILO-VOLT-AMPS (KVA).
MINIMUM AMPS: - a term used in BLASTCALC that denotes the minimum firing current that each cap requires for complete initiation without arcing. Normally the range of current required is 0.6 - 10 amps for 100 % initiation (based on firing characteristics and statistics for standard bridgewire electric caps.)
SLIT AND TAMPED: - a general term, also used in BLASTCALC, that describes a method of loading cartridged explosive loads into boreholes. Cartridges are first slit with a suitable cutting edge, dropped in the borehole and then individually tamped to obtain higher coupling ratios and hence increased powder factors compared to string loaded cartridged loads. See also STRING LOADED.
STRING LOADED: - a method of loading boreholes using cartridged explosive loads by simply placing one cartridge after another down the borehole alternately tamping them as they are loaded. This technique is often used in wet boreholes particularly if the cartridged explosive product is water sensitive without the intact cartridge covering. Slitting would remove this protection of the outer wrapping, therefore explosive loads which fall into this 'water-sensitive' category would be string loaded. See also SLIT AND TAMPED.
LOOSE: a term used in underground mining which describes rock on tunnel surfaces that has become detached through the action of stress buildup or blasting and has the potential of falling, causing serious injury to mining personnel or damage to mining equipment.    Mining operations in general take great care in scaling 'loose' so that accidents can be prevented. Rockbolts and Screens are used to contain any rock which may have the potential of becoming 'loose* as part of the safety procedures which mines generally follow
WALL CONTROL: - a term describing procedures that surface mining operations use to insure the safety of pit or quarry walls, even extending to perimeter control for roadways and other types of civil engineering projects. Wall Control involves the design of production blasting operations so that minimum stress is generated at the excavation limit so that the formation of unstable masses of rock can be eliminated. Cracks extending into the excavation limit can cause rock falls, particularly upon weathering of the rock as time progresses. Such cracking can be prevented by drilling pre-shear lines to form stable slopes. See PRE-SHEARING.
SEISMIC MONITORING: - a term used with respect to blasting operations such that particle acceleration, velocity, and displacement can be monitored by seismographs to provide data that can characterize the attenuation attributes of a specific blasting site. This assists blasting engineers in predicting potential damage levels caused by initiating too many pounds of explosive loads/delay period. Damage level varies tremendously (depending on specific structures to be protected), and has been found to correlate best with particle velocity at specific frequencies. Damage occurs for man-made structures, such as buildings, other structures, at frequencies typically below 20 HZ and at levels of .5 in/sec or greater. Human response is much more acute and has much lower limits. To develop an attenuation curve, seismograph readings are taken at different distances away from blasting operations to measure peak particle velocity. Particle velocity is then plotted against scaled distance (see SCALED DISTANCE) for prediction purposes.
VOD: - a short form of the expression 'velocity of detonation'.
CHAPMAN-JOUGUET PLANE: - the 'C-J' plane can be simply defined as a 'condition' of chemical equilibrium such that the detonation reaction is complete so that a permanent steady-state reaction is able to continue with stability. It defines the outside back boundary of the reaction zone, when a stable steady-state supersonic shock condition exists.
LEDC: - a short form term for the expression 'low energy detonating cord'. Low energy detonating cord has its cord load restricted to typically less than 10 grains/ft and more specifically 4 grains/ft.
BOREHOLE DEPTH: - a term used in BLASTCALC to define the total borehole depth including any subdrill/subgrade.
BOREHOLE DIAMETER: - a term used in BLASTCALC to define borehole diameter.
CUMULATIVE TOTALS: - a term used in BLASTCALC to define the running totals of explosive load weights, numbers of caps, numbers of primers, etc.
DEPTH OF WATER: - a term used in BLASTCALC which defines the amount of water in a borehole. The measurement is the column height of water in a borehole measured from the bottom of the borehole.
LOAD NAME: - a term used in BLASTCALC which defines the explosive load trade name.
COUPLING MEDIUM: - a term used in BLASTCALC that defines the coupling material or medium between a decoupled explosive load and the borehole wall. BLASTCALC currently deals with four types of coupling media: CLD - fully coupled to the rock, DRY - explosive load air-coupled to rock, WET - explosive load water-coupled to rock, AGG - explosive load water-coupled to the rock.
MINIMUM CONFINEMENT: - a term used in BLASTCALC that describes a minimum confinement level for use in predicting peak particle velocity. Minimum confinement refers to a blast that has little confinement, - open on at least one free face side, and that is able to move out unimpeded.
MODERATE CONFINEMENT: - a term used in BLASTCALC with regard to seismic prediction of particle velocity, - when a blast is moderately confine, such as buffer blasting.
MAXIMUM CONFINEMENT: - a term used in BLASTCALC involving the prediction of peak particle velocity from blasting operations. MAXIMUM CONFINEMENT refers to blasts which are totally confined, such as sinking cuts, trench blasting operations where there are virtually no free faces to allow burden movement.
BENCH HEIGHT: - the height of the free face from the base of the bench to the top of the bench. This measurement does not include any subdrill or subgrade.
EXPLOSIVES COST: - a term used in BLASTCLAC to define just the explosive cost including the cost of the explosive load, blasting cap and primer.
PRIMING COSTS: - a term used in BLASTCALC which denotes only the cost of blasting caps and primers and not the explosive load.
COLLAR/STEM LEFT: - a term used in BLASTCALC to denote the amount of space between the top of the column load and the top of the borehole that is usually fill with stemming material such as aggregate, fine sand or drill cuttings.
CONTACT PERSON: - a definition in BLASTCALC which describes the person with whom you are in direct communication with, concerning the use of BLASTCALC as a tool for answering specific blasting related problems.
OPERATION: - a term definition used in BLASTCALC which describes the type of industry whether it be mining or otherwise; - e.g. OPEN PIT MINE, QUARRY, CONSTRUCTION, SEWER CONTRACTOR, PIPELINE, CONSULTING AGENCY, etc.
CAP SENSITIVE: - a level of sensitivity of an explosive product or formulation such that it will completely detonate when primed or initiated by an ordinary strength blasting cap. In the U.S. No. 8 blasting caps have 8 grains of base charge usually PETN, whereas in CANADA, the standard strength is a No. 12 blasting cap, having 12 grains of PETN as the base charge.
TRANSIENT PRESSURE: - a pressure obtained from detonating explosive charges which is the result of gases expanding in the rock mass to atmospheric pressure. Transient pressures have been found to be quite high in water-saturated rock since the gases try to occupy the spaces filled by trapped water. These pressures can desensitize other explosives since the micro air pockets in adjacent loaded boreholes containing the explosive charge, can be squeezed out - reducing the reaction rate. Explosives used in trenching applications (small diameter) or sinking cuts are usually formulated to overcome this problem. Drifting is another application where transient pressure phenomena occurs.
SYNERESIS: - a tightening up of gel structures particularly in slurry/watergel explosives. This phenomenon has the effect of squeezing the liquid phase of explosive formulations out of the gel structure. The explosive material appears to be 'sweating'.
GUAR GUM: - a gel forming ingredient found in some watergel explosive products. This material is obtained from the quar bean in INDIA, and can be cross-linked to form a gel-like structure. It is used in foodstuffs and is environmentally safe.
WORK EFFECTIVE: - sometimes called effective blasting energy which actually participates in the breakage and movement of the rock. Excludes heat loss, crushing energy near the borehole wall and energy wasted by gas expansion through cracks.
VERTICAL STRESS FIELD: - the stress field associated with the action of gravity due to the weight of rock covering an underground installation.
HORIZONTAL STRESS FIELD: - a stress field associated with the tectonic stress field resulting from tectonic plate movement within the earth's crust. This stress field acts mostly in the horizontal plane.
ACOUSTICAL IMPEDANCE: - classification of a material regarding its energy transfer properties using mathematical expressions. Normally defined as the product of its unit density and the velocity of sound in the specific material type.
AIRDOX: - a system that utilizes 10,000 psi compressed air to fracture undercut coal. Airdox is ideally suited to this type of mining environment since it will not ignite gassy or dusty atmospheres.
ADOBE CHARGES: - see mud capping.
AMERICAN TABLE OF DISTANCES (USBM): - "a quantity/distance table published by the IME as PHAMPLET NO. 2 which specifies safe explosive storage distances from inhabited buildings, public highways, passenger railways and other stored explosive materials".
AXIAL PRIMING: - a technique for priming blasting agents (watergels and ANFO) by tracing the borehole axially with detonating cord to reduce the detonation velocity of the explosive load. See traced velocity.
BACK HOLES: - defined as the top holes in a tunnel or drift round.
BATF: - the BUREAU OF ALCOHOL, TOBACCO AND FIREARMS, U.S. DEPARTMENT OF THE TREASURY, which enforces explosives control and security regulations.
BENCH: - a horizontal ledge or structure in a surface operation (quarry, or open pit) where vertical boreholes are drilled. Terraces or ledges are worked in a stepped sequence in order to provide stability of the pit wall.
BINARY EXPLOSIVE: - an explosive that can be produced by mixing two non-explosive ingredients such as nitromethane and ammonium nitrate, which can be shipped and stored separately, but mixed at the blast site to form the high explosive product.
BLAST: - detonating explosive charges drilled in rock to break the rock.
BLAST AREA: - the area in the immediate vicinity of blasting operation which may be affected by flyrock or blast products such as concussion.
BLASTER: - a qualified person regarding the handling and firing of explosives. Usually a blaster's license is required certifying his/her qualifications to supervise blast loading and other activities.
BLASTING CAP: - a detonator that can be initiated by safety fuse (MSHA). See also detonator.
BLASTING CIRCUIT: - an electrical circuit that is used to fire one or more electric blasting caps.
BLASTING CREW: - a group of individuals/personnel that are assigned the task of loading explosive charges.
BLASTING MACHINE: - machines that are specifically built for the purpose of providing suitable energy to electric blasting caps or other initiators.
BLASTING MAT: - See mat.
BLASTING SWITCH: - a switch used to connect power to blasting circuits.
BOREHOLE: - a hole drilled in rock to permit the loading of explosives.
BRIDGE WIRE: - a fine nichrome filament wire that is placed in the ignition charge of an electric blasting cap. Electric current provides sudden heating of the filament to such an extent as to produce a sudden heat rise resulting in the ignition of the charge - detonating the cap.
BUBBLE ENERGY: - expanding gas energy of an explosive which is measured using pressure sensors in an underwater test.
BULK MIX: - explosive material which is manufactured usually at the site of usage, without packaging. (Bulk loaded explosive material as made on bulk trucks).
BURN CUT: - a parallel hole cut using several closely spaced production holes in which not all of the holes are loaded with explosives. These holes are relief holes.
BUS WIRES: - two wires joined to connecting wire, usually CABTYRE wire - a heavy gage duplex wire or cable, to which leg from electric blasting caps are connected in a parallel circuit. Each leg wire is connected to one of the lengths of bus wire to make the circuit connection.
CAPPED FUSE: - length of safety fuse to which a blasting cap has been attached and crimped.
CAPPED PRIMER: - a cartridge of cap-sensitive explosive material which is specially designed to detonate other explosives. A capped primer contains a detonator.
CARBON MONOXIDE: - a poisonous gas created by detonating explosive materials which have not been oxygen balanced. Caused by an inadequate amount of oxygen in the explosive, i.e. - the explosive is fuel rich.
CARDOX: - a system which uses a container or cartridge filled with liquid carbon dioxide which breaks undercut coal by initiating a mixture of potassium perchlorate and charcoal creating pressure.
CHAMBERING: - a method of enlarging a portion of a borehole, - usually the bottom, by firing a series of small explosive charges. Chambering can also be done by mechanical or other methods.
CARTRIDGE: - a rigid or semi-rigid container of explosive material of a specific length and diameter.
CARTRIDGE STRENGTH: - an explosive rating that compares a specific volume of explosive material with an equivalent volume of straight nitroglycerine dynamite, - expressed as a percentage or on a base of 100.
CAST PRIMER: - a solid unit of explosive, either comprising TNT, PENTOLITE, or COMPOSITION B, which is used to initiate the detonation reaction in a blasting agent, or non-cap sensitive explosive.
CLASS A EXPLOSIVE (DOT DEFINITION): - an explosive that has detonating or otherwise maximum hazard; such as, but not limited to, DYNAMITE, NITROGLYCERINE, LEAD AZIDE, BLACK POWDER, BLASTING CAPS and DETONATING PRIMERS
CLASS C EXPLOSIVE (DOT DEFINITION): - explosives that contain CLASS A or CLASS B explosive, or both, as components but in restricted quantities. For example, blasting caps or electric blasting caps in lots of less than 1,000.
CLASS B EXPLOSIVE (DOT DEFINITION): - explosives that have flammable hazards; such as, but not limited to, propellant explosives, photographic flash powders, and some special fireworks.
COMMERCIAL EXPLOSIVES: - explosive products designed specifically for commercial or industrial applications, rather than military applications.
COMPOSITION B: - a mixture of RDX and TNT that has when cast, a density of 1.65 g/cu cm and a velocity of 25,000 fps. Commonly used as primer material for blasting agents.
CONFINED VELOCITY: - the detonation velocity of explosive material confined in boreholes. Some explosive manufacturers used steel or aluminum pipe to simulate confinement when formulating and testing explosive formulations. It has been found by experiment that wall thicknesses in excessive of .375 in. simulates borehole conditions of confinement quite closely.
CONNECTING WIRE: - small gage wire, - typically 22 gage, which is used in a blasting circuit to extend leg wires out of a borehole, or from one borehole to another.
CORDEAU DETONANT FUSE: - French translation of detonating cord.
CORNISH CUT:  - See parallel hole cut.
COROMANT CUT:  - See parallel hole cut.
CURRENT LIMITING DEVICE: - a special device which is used to prevent current from arcing in electric blasting caps by limiting the amount or duration of the current. Blasting galvanometers and multimeters are protecting in this manner.
DECIBEL: - a unit of sound pressure that is used to measure noise or airblast from sound sources or blasting operations. It is a logarithmic measurement and is represented by the formula N = 20 log P/Pr, where N is sound pressure level in decibels, P is the effective sound pressure measured in newtons/square meter, and Pr is the reference pressure in air equal to 0.0002 microbars, or 2 dynes/square centimeter.
DEFLAGRATION: - a rapid explosive reaction that is subsonic, that includes high gas pressures and borehole pressures in the absence of shock.
DELAY BLASTING: - blasting operations which include the use of short or long delay detonators or connectors. This has the effect of limiting large quantities of explosives to smaller charges that detonate in a controlled sequence for purposes of optimizing fragmentation.
DELAY CONNECTOR: - a nonelectric, short-interval delay device for use in delaying blasts that are initiated by detonating cord.
DELAY DETONATOR: - An electric or nonelectric detonator with an internal delay element which creates a delay between the starter charge in the ignition cup and the base charge of the detonator.
DELAY ELECTRIC BLASTING CAP: - an electric blasting cap with an internal delay that predetermines cap detonation at specific time intervals (millisecond to 1 second) between successive delays.
DELAY ELEMENT: - the internal pyrotechnic delay device that contains specific slow burning chemicals which provides a time delay from the instant that the chemical starts to burn (upon application of suitable ignition energy) to the detonation of the base charge of the detonator or cap. The delay element itself is formed from lead tubing filled with the appropriate delay composition. Elements are checked against statistical standards of specific time intervals - e.g. 25MS, 50MS, 75MS etc. for accuracy.
DEPARTMENT OF TRANSPORTATION (DOT): - a U.S.A. Federal Agency that regulates safety in interstate shipping of explosives and other hazardous materials.
DETALINE SYSTEM: - a nonelectric initiating system for detonating blasting caps in which the energy is transmitted through a hookup using low energy detonating cord.
DOWNLINE: - the portion of detonating cord which is placed in a borehole and transmits the shock wave energy from trunkline to the primer down the borehole
DROP BALL: - an iron or steel weight which is raised by wire rope and then dropped onto secondary material in order to break it up into smaller pieces.
ECHELON PATTERN: - an open pit/quarry delay pattern that orients the burden at the time of detonation to be positioned at an oblique angle from the original free face.
ELECTRIC STORM: - an atmospheric disturbance of intense electrical activity (lightning) which produces an extreme hazard for all blasting operations.
EXPLODING BRIDGE WIRE: - a resistance wire that explodes upon the application of electrical current, taking the place of the primary explosive usually placed in the ignition cup. This type of electric blasting cap detonates instantaneously and is used in those cases where very precise timing is needed - e.g. seismic surveying, ultra-high speed streak and framing camera work.
EXPLOSION: - a thermochemical reaction which results in extremely fast decomposition of chemical compounds which release mixtures of gases, solids and liquids producing gas pressure and heat.
EXPLOSIVE MATERIALS: - materials which include dynamites and other high explosives, including watergels, emulsions, blasting agents, black powder, military explosives, detonators, safety fuses, squibs, igniter cord, detonating cord and pellet powder.
EXTRA DYNAMITE: - also called ammonia dynamite which obtains most of its energy from ammonium nitrate.
FIRING CURRENT: - electric current which flows in a blasting circuit in order to initiate blasting caps. It must have a specific value in order to detonate an electric blasting cap. In many instances, this value is chosen to be 1.5 amps (amperes) DC or 3.0 amps (amperes) AC for 100% initiation of blasting caps (including a safety factor).
FIRING LINE: - a special electric wire which can be affixed permanently (CABTYRE) from the shot firing machine (transformer etc.) to the blasting location.
FLASH OVER: - propagation or sympathetic detonation between explosive charges or adjacent loaded blastholes.
FLYROCK: - pieces of rock that are violently propelled through the air from blasting operations. Excessive flyrock can be produced by poorly designed blasting operations or unexpected zones of weakness in rock.
FUEL: - one of the main ingredients of an explosive formulation which reacts with an oxidizer to produce gaseous products, solids from the detonation process.
FUEL OIL: - for use in ANFO, usually No. 2 diesel fuel, mixed in the proportion of 94% ammonium nitrate to 6 % fuel oil.
FUSE LIGHTER: - a pyrotechnic device for the lighting of safety fuse.
FUME QUALITY: - a measure of the toxic fumes to be expected when a particular explosive is properly detonated. See fumes.
GALVANOMETER: - a blaster's galvanometer - an instrument which uses a silver chloride cell or current limiting device to measure resistance in an electric blasting circuit. These instruments are the only type of resistance measuring devices that are permitted to be used with blasting caps. DO NOT USE ORDINARY MULTIMETERS SUCH AS THOSE AVAILABLE IN ELECTRONIC SUPPLY OUTLETS - USE OF THESE TYPES COULD COST YOU YOUR LIFE!
GAP SENSITIVITY: - the measured distance across which a specific explosive formulation can propagate or 'jump'. There are air gaps or specific solid gaps that are defined for certain explosive types.
GAS DETONATION SYSTEM: - a system for initiating caps in which the energy is transmitted through the circuit by means of shock transmission through gas mixtures such as acetylene and oxygen.
GELATIN DYNAMITE: - a blasting gelatin dynamite which is highly resistant to water.
GROUND VIBRATION: - vibrations produced in the ground from blasting operations caused by traveling elastic waves such as longitudinal and shear. Ground vibrations can cause structural damage. Magnitudes and frequencies of blast induced ground vibrations can be measured using seismographs. Both the U.S.A and CANADA have strict regulations governing the limits of peak particle velocity and frequency and their effects on structures.
HANGFIRE: - the detonation of an explosive charge at a time after its designed firing time. Can be a source of very serious incidents.
HEADING: - an excavation or drift driven horizontally in an underground mine.
HIGHWALL: - this is a bench or ledge at the perimeter of a surface excavation such as an open pit mine or quarry. This term is most often used in coal strip mining.
IGNATICORD: - a cordlike fuse that burns progressively along its length with
an external flame at the zone of burning and is used for lighting a series of
safety fuses in sequence. The flame produces spits similar to a sparkler.
IME: - the short form for Institute of Makers of Explosives, which is a trade organization dealing with the use of explosives. It is concerned with safety in manufacture, transportation, storage, handling and use. This organization publishes information on blasting safety.
INITIATION: - the act of detonating a high explosive using a cap, or mechanical device or another method.
INSTANTANEOUS DETONATOR: - a detonator which contains no delay element.
JET LOADER: - a pneumatic loader for ANFO that can be used to charge small diameter blastholes to elevated densities above 0.85 g/cu cm. A venturi is used to propel the ANFO prills at high velocity through semiconductive hose. Prills breakdown in the airstream and when impacted at the borehole bottom as well as the borehole sides.
JUMBO: - a drilling machine designed to drill multiple boreholes at the same time, - since it has two or more separate drilling rigs mounted on a boom which can be operated independently of one another.
KERF: - a slot cut in a coal or soft rock face using a mechanical cutter such that a free face is produced for blasting.
LEAD WIRE: - wire which is used to connect the electrical power source with the leg wires or connecting wires of an electric blasting circuit. Can be called firing line.
LEG WIRES: - wire which is connected internally to the cap, and directly to the bridge wire through a waterproof crimped plug. Leg wires have standard sizes and at the opposite end use a foil wrap which acts as a short to prevent stray current pickup or radio frequency pickup.
LIQUID OXYGEN EXPLOSIVE: - a high explosive made by soaking cartridges of carbonaceous materials in liquid oxygen. Very seldom used today, not a modern explosive.
LOADING FACTOR:  - See powder factor.
LOADING POLE: - a wooden pole (made of nonsparking material) which is used to tamp explosive cartridges in boreholes in order to compress them to provide a better coupling ratio. Light force should only be used to avoid excessive shock which might damage or initiate a blasting cap. USE CARE!
LOX: - short form for liquid oxygen. See also LIQUID OXYGEN EXPLOSIVES.
MAGAZINE: - a building, structure or container that is specifically designed to store explosive materials. This are designed to stringent standards in both the U.S.A and CANADA and must meet federal codes with regard to inspection.
MAT: - a heavily constructed covering such as those made with discarded automobile tires. Can also be made of heavy wire rope and cable.
MAXIMUM FIRING CURRENT: - the largest or highest current (amperes) that is recommended for the safe and successful initiation of an electric blasting cap
METALLIZED: - used in terms of explosive formulations. A blasting agent can be sensitized with airtrapping aluminum powder, flake, or atomized aluminum particles. Adds energy to the formulation as well.
MICHIGAN CUT: - See parallel hole cut.
MILLISECOND: - used in terms of short delay caps. Standard form is 25MS, - where MS is interpreted as Milliseconds.
MILLISECOND DELAY CAPS: - delay detonators either nonelectric or electric or as used in surface delays. They have internal delay elements that add time to the application of energy to the blasting circuit whether nonelectric or electric. Most delays are cumulative since each detonator has a specific time delay, such as 25MS, 50MS etc.
MINIMUM FIRING CURRENT: - the lowest current (amperes) that can initiate an electric blasting cap within a specified short time interval.
MAN (MONOMETHYLAMINENITRATE): - an explosive sensitizer originally developed by the German Army at the end of the Second World War, since their supplies of TNT were diminishing. It is nitrated METHYLAMINE which is an organic dye.
MS CONNECTOR: - a blasting accessory used as a delay in a detonating cord circuit connecting one hole to another or one row to another.
MSHA: - in the U.S.A., the MINE SAFETY and HEALTH ADMINISTRATION. This is an agency under the Department of labor which enforces health and safety regulations in the mining industry.
MUCK PILE: - the blasted out pile of broken rock which will ultimately be loaded on heavy trucks or loaders or scoops for transportation to the crusher and then the mill.
MUD CAP: - referred to as adobe, bulldoze, blistering, or plaster shot. Basically a charge is placed in intimate contact with the secondary rock surface with mud (used as a shock transmissive agent) in order to break up the boulder.
MULTIMETER: - a multipurpose test instrument used to check line voltages, firing circuits, stray currents, current leakage as well as other measurements that are specific to electric blasting. Only a meter specifically designated as a blaster's multimeter or blaster's galvanometer should be used to test electric blasting circuits. DO NOT USE THOSE TESTERS THAT ARE PURCHASED FROM ELECTRONIC SUPPLY OUTLETS!
NFPA (NATIONAL FIRE PROTECTION ASSOCIATION): - an industry/government association that publishes standards for explosive material and ammonium nitrate.
NITROMETHANE: - a liquid compound used as a fuel in two-component (binary) explosives and as rocket fuel. Also has been used to fuel ammonium nitrate in order to give a higher energy explosive.
NITROSTARCH: - a granular, solid explosive, very similar to nitroglycerine but is made by some manufacturers and advertised as non-headache producing explosive - replacement for dynamite.
NONELECTRIC DELAY BLASTING CAP: - a detonator comprising a delay element capable of being initiated using nonelectric means - using shock tubes, low energy primacord, and gas filled tubing.
OSHA: - in the U.S.A., the Occupational Safety and Health Administration. An agency under the Department of Labor which enforces health and safety regulations in the construction industry, including blasting.
OSMRE: - the Office of Surface Mining Reclamation and Enforcement. An agency in the U.S.A. under the Department of Interior which enforces surface environmental regulations in the coal mining industry.
OVERDRIVE: - a measureable increase in the steady-state detonation velocity of an explosive material. This is primarily due to an increase in density immediately off the end of detonating primers and results from the increased explosive material density from mechanical shock wave impact from the primer. The detonation reaction is partially forming in the explosive material as a result of the impulse given by the primer. This raises the density of the explosive material slightly producing increases in the initial velocity of detonation. It is a short-lived phenomenon.
PARALLEL CIRCUIT: - a circuit in which two wires (bus wires) are separated in order to permit the attachment of one cap leg wire to one bus wire, with the other cap leg wire attached to the other. Blasting caps tied in this way are considered to in a parallel circuit configuration.
PARALLEL HOLE CUT: - groups of parallel holes, some which are loaded with explosives are used to establish a free face in tunnel or heading blasting. One or more of the unloaded holes may be larger than the blastholes. Also called Coromant, Cornish, burn, shatter, or Michigan cut.
PARALLEL SERIES CIRCUIT: - Similar to a parallel circuit, but consisting of two or more series of electric blasting caps. One end of each series of caps is connected to each of the bus wires. Can be called a series-in-parallel circuit.
PELLET POWDER: - consists of black powder pressed into 2 in. long, 1.125 - 2 in. diameter cylindrical pellets.
PERMISSIBLE: - any kind of device, material, apparatus or other contrivance that has been specifically analyzed, tested and approved by the U.S. Bureau of Mines, or in Canada - CANMET and provincial regulatory bodies for use in specific areas of hazard (such as coal mines where there is a potential methane gas hazard). Must be maintained in permissible conditions.
PERMISSIBLE EXPLOSIVES: - explosive formulations that have been approved by MSHA or Canadian CANMET authorities and governing bodies for usage in underground coal mines or other potential gassy mines.
PLACARDS: - special signs placed on transporting vehicles of hazardous materials such as explosives or other cargo which specify the type of cargo and its nature.
POWDER CHEST: - a heavy constructed, nonconductive portable container equipped with a secure lid that can be locked (tamperproof) - used at blasting sites for temporary storage of explosives.
PRE-BLAST SURVEY: - a written document which establishes the existing condition of a structure with regard to settlement cracks, any structural damage that is current, and most specifically existing cracks in plaster walls. Such pre-blast surveys are used to determine if subsequent damage (lengthening of cracks, etc.) is the result of ongoing blasting operations.
PREMATURE: - a condition of blasting such that an explosive charge detonates before its designated detonation time. This situation can be dangerous since a premature detonation of a borehole in a firing sequence has the potential of producing cutoffs of other blastholes. Poor fragmentation will also result.
PRESSURE VESSEL: - an ANFO loading system specifically designed for small diameter boreholes usually drilled in underground mines (drifting, etc). ANFO is contained in a sealed pressure vessel, pressurized using air from the mine air supply, and then blown through semiconductive hose into a blasthole. In the process, some of the prills are broken down to enable the ANFO explosive to shoot in such small diameter holes. The ANFO is also packed producing a higher bulk density.
PRIMARY BLAST: - priority blasting operations that sustain feed to crushers and mills in order to keep production rates at a predetermined level.
PRIMARY EXPLOSIVE: - an explosive material which is sensitive to minute energy inputs such as is obtained from sparks, flame, impact, friction, shock tubes and used in a detonator to initiate the base charge (usually PETN).
PROPAGATION BLASTING: - a pattern of closely spaced blastholes which contain shock sensitive explosives used to excavate ditches in wet or damp open ground - usually for ditching. Because of the difficulty of charge placement in ground such as this (swampy), it is more prudent and safer to use only one detonator. Many of the charges must be firmly poled into position.
PROPELLANT EXPLOSIVE: - an explosive material that normally deflagrates and is used for propulsion.
PULL: - a quantity of rock or length of advance excavated by a blast round.
RDX (CYCLOTRIMETHYLENETRINITRAMINE): - an explosive substance used in the manufacture of compositions B, C-3 and C-4. Composition B is used as an ingredient for cast primers.
RELIEVERS: - in underground mining in a heading round, relievers are holes adjacent to the cut holes and are used to expand the opening made by the cut holes.
RIB HOLES: - holes that are drilled at the sides of tunnel or drifts rounds. They determine the width of the underground opening.
RIPRAP: - large boulders or coarse rocks used for embankment control for rivers; dam stabilization. Prevents bank erosion by water flow.
ROTATIONAL FIRING: - a delay blasting system such that each charge successively displaces its burden into a void which is created by an explosive charge detonated on an earlier delay period.
SEMICONDUCTIVE HOSE: - a loading hose used for pneumatic conveying of ANFO which has a minimum electrical resistance of 1,000 ohms/ft and 10,000 ohms total resistance and with a maximum total resistance of 2,000,000 ohms.
SEQUENTIAL BLASTING MACHINE: - a blasting machine which contains a series of capacitor discharge circuits in a single unit and which can be activated at accurately timed intervals producing sufficient electric current to initiate an electric blasting caps.
SERIES CIRCUIT: - a circuit such that each electric cap leg wire is connected to a leg wire from the adjacent caps so that current flows in a single path through the entire circuit.
SERIES-IN-PARALLEL CIRCUIT: - See parallel series circuit.
SHATTER CUT: - See parallel hole cut.
SHELF LIFE: - the storage time that an explosive can have without losing its efficiency. Also the length of storage time that can be tolerated from a safety standpoint when explosive formulations begin to break down and segregate or 'sweat1 due to harsh environmental influences such as heat and cold.
SHOCK ENERGY: - the shattering force or momentum condition of the shock wave produced by an explosive when it detonates.
SHOCK TUBE SYSTEM: - a system for initiating blasting caps nonelectrically when energy is transmitted to the ignition charge of a detonator by means of a shock wave traveling inside a hollow plastic tube.
SHOT-FIRER: - the individual who takes responsibility for firing a blast.
SILVER CHLORIDE CELL: - a low-current voltaic cell used in blasting galvanometers and other instruments to measure circuit continuity in an electric cap hookup. Current output for these cells is typically less than 50 milli-amperes.
SNAKE HOLE: - a blasthole drilled slightly downward from the horizontal into the floor of a quarry face usually where there is excess burden due to insufficient energy or sub-drill. Also, a blasthole drilled under a boulder.
SODIUM NITRATE: - an oxidizer used in dynamites and blasting agents.
SUBSONIC: - slower than the speed of sound.
SUPERSONIC: - faster than the speed of sound.  In excess of Mach 1.
SWELL FACTOR: - the ratio of the volume of a material in its solid state to that when it is broken. It can be expressed as a reciprocal.
TAMPING BAG: - a cylindrical bag sometimes containing stemming material (drill cuttings, etc.), which is used to confine explosive charges and loads in blastholes.
TEST BLASTING CAP No. 8: - a blasting cap containing .4 to .45 g of PETN explosive as a base charge having an SG of 1.4 g/cm3, and primed with standards weights of base charge, depending on the manufacturer.
TRANSIENT VELOCITY: - a varying, non-constant detonation velocity which deviates from the steady state velocity of an explosive formulation. Insufficient primer weight can produce this effect which results in detonation velocity run-up to steady state. See run-up.
RUN-UP: - the distance required for a detonation reaction to become complete contributing to a constant, non-varying detonation velocity. Run-up becomes more pronounced as borehole diameters or charge diameters decrease. A sufficient amount of explosive ingredients must react in the detonation head to keep it propagating.
TWO-COMPONENT EXPLOSIVE: - See binary explosive.
UNCONFINED DETONATION VELOCITY: - the detonation velocity of an explosive formulation that is not confined by a borehole or other confining medium like a steel or aluminum pipe.
V-CUT: - a cut using several pairs of angled holes which tend to meet at the bottom, used to produce free faces for the rest of a blast round.
VENTURI LOADER: - See jet loader.
WATER RESISTANCE: - a relative or qualitative measure of the ability of an explosive material or structure to resist water penetration into it. When water penetrates into explosive materials, they become deteriorated or desensitized.
WATER STEMMING BAGS: - special plastic bags containing a self-sealing device that permit water to be retained in the bag for the purpose of stemming explosive charges - permissible units approved by MSHA.
CHARGE: - in mining, - referring to an explosive material which is loaded into a blasthole, positioned in such a manner for the breakage of rock. Can also refer generally to any explosive material occupying space and is set for the function of detonation.
RUN-DOWN: - the opposite of run-up. A condition of the detonation reaction such that the fraction of ingredients reacting in the detonation head is not sufficient to sustain the detonation reaction with the result that the explosive charge or column fails to detonate completely. The detonation reaction simply 'dies out' due to lack of energy contribution from the chemical reaction behind the high pressure shock front. Run-down can occur close to the critical diameter if environmental influences such a temperature are extreme (cold).
RADIAL VELOCITY: - the detonation velocity measured radially from an axial primer such as primacord (placed along the longitudinal axis of an explosive charge in a blasthole). Experiment has shown that the radial velocity for most explosive types having critical diameters typically greater than 1 in., is roughly 1/2 the ideal velocity measured at the ideal (largest) charge diameter
d* DIAMETER: - the ideal diameter of an explosive charge, - typically that diameter in which the ideal detonation velocity is measured. This diameter would be 15 in. for ANFO, 3 in. for a typical small diameter watergel explosive or 2 in. for a high strength dynamite.
D* VELOCITY: - represents the ideal detonation velocity measured in the largest possible diameter of charge of a specific explosive formulation. The ideal velocity can also be calculated by thermohydrodynamics however can easily be obtained by experiment. To obtain both the ideal diameter (d*) of a specific formulation as well as the ideal detonation velocity (D*), velocity/diameter curves can be developed in which the detonation velocity is measured in increasing charge diameters. When the detonation velocity remains constant and fixed at some specific value regardless of increasing the charge diameter further, then the detonation velocity has therefore been determined. The charge diameter which is lowest diameter to give this velocity, is referred as the ideal charge diameter (d*).
AMBIENT: - refers to environmental (weather) conditions at the time. Ambient temperature refers to the temperature reading at the time of explosive usage, or test condition. Present temperature conditions.
COLUMN RISE: - when explosives are loaded into boreholes they naturally 'rise' in the borehole. Column rise refers to the natural condition of loading explosive in boreholes to specific distances from the borehole bottom. Column rise is measured in terms of lbs/ft of borehole. Density strongly affects column rise.
YARDAGE: - a term used in BLASTCALC to define the number of cu yd in a blast having a specific geometry.
TONNAGE: - a term used in BLASTCALC that is used to define the weight of rock in tons (metric-tonnes) that can be blasted with a specific blast geometry.
S/B RATIO: - a term used in BLASTCALC that defines the ratio of spacing to burden. When spacing equals burden, the S/B ratio would be 1.
SQUARE ROOT SCALING: - the objective of scaling blast vibrations is the designation of relationships correlating ground motions levels at various distances from blasts of different sizes. Principal factors affecting vibration levels at a given point are, - weight of explosive fired, distance from the blast, the delay period used (if any), and the blast geometry. The explosive column approximates the shape of a cylinder having a much greater than 6 to 1 length to diameter ratio. The expanding wave front from charges such as these adopt an expanding cylindrical shape, the volume of this compression cylinder varies as the square of its radius. Thus the peak particle motion at any point from this type of shot will be inversely proportional to the square of the distance from the blast. This is called 'SQUARE ROOT SCALING'.
CORD LOAD: - the number of grains/ft present in a primacord defining its strength - e.g. 50 gr/ft denotes trunkline.
AMPLITUDE: - the maximum displacement from the position of rest and is measured in in/sec with regard to peak particle velocity measurement. The maximum excursion from initial conditions with regard to other measurements.
VOLTAGE: - the volt is the difference of electric potential between two points
of a conducting wire carrying a constant current of one ampere, when the power
dissipated between these points is equal to one watt.
RESISTANCE: - the ohm is the electric resistance between two points of a conductor when a constant difference of potential of one volt, applied between these two points, produces in this conductor a current of one ampere, this conductor not being the source of any electromotive force.
AMPERE: - the ampere is an electrical current of such magnitude that when maintained in two straight parallel conductors of infinite length, negligible circular cross sections, and placed 1 meter apart in a vacuum, will produce between these conductors a force equal to 2 x 10~-7 newton/meter of length.
DEGREE KELVIN: - the thermodynamic Kelvin degree is determined by the Carnot
cycle with the triple-point temperature of water and defined as exactly 273.16
degrees Kelvin.
EGMN (ETHYLENE GLYCOL MONONITRATE): - an explosive sensitizer used in watergel explosives.
JOULE: - the joule is the work done when the point of application of one newton is displaced a distance of one meter in the direction of the force.
BOYLE'S LAW: - INITIAL P1V1=FINAL P2V2 (at constant temperature) where Pl=initial gas pressure, Vl=initial volume, P2=final gas pressure, V2=final gas volume.
LOAD WEIGHT: - a term used in BLASTCALC which defines the load weight of a specific explosive type used in a borehole as an explosive load.
REGRESSION EQUATION: - either a linear or nonlinear fit of a regression line to a series of data points. The line with pass through the data with the best possible fit for the purpose of developing an equation in order to satisfy the mathematics of the defined fit.
Lg PV: - the logarithmic value of the particle velocity - a term used in BLASTCALC.
Lg SD: - the logarithmic value of scaled distance - a term used in BLASTCALC.
SD: - short form for scaled distance - a term used in BLASTCALC.
PPV: - short form for peak particle velocity - a term used in BLASTCALC.
PV: - short form for particle velocity - a term used in BLASTCALC.
INTERPOLATED VELOCITY: - a term used in BLASTCALC that denotes the detonation velocity which is mathematically fitted to a regression line and is included as part of the data set, - load diameter. When a specific load diameter is input into the data table, a detonation velocity is mathematically obtained which best fits this input - the velocity is therefore interpolated from all the data used to generate the best fit.
DETONATION VELOCITY: - the detonation velocity of an explosive formulation is dependent on the type of chemical ingredient which constitute it. The detonation reaction can be described as a chemical reaction in which a shock wave is reinforced and fed by the chemical reaction preceding it. Immediately in front of the reaction zone is a high pressure shock front which compresses the explosive material in front of it. In the highly ionized reaction zone behind the shock front, pressures are lower, temperatures are high, and the resulting shock waves (release waves) which are formed by impedance mismatch between the explosive material and the borehole wall, rebound forming a detonation head in which additional reaction of ingredients takes place. The detonation velocity is basically the rate at which the detonation head propagates through the unreacted explosive.
STEMMING/COLLAR: - a term used in BLASTCLAC which denotes the amount of borehole remaining in which no explosives will be loaded. Most often the collar is filled with drill cuttings in order to provide confinement for the detonating explosive.
LOAD COST: - the cost of the explosive used in a particular borehole. Does not include blasting caps, or any other accessories.
CRITICAL DAMPING: - a value of damping which produces the most rapid transient response without overshoot of the output signal of a transducer upon receipt of a step input.
DAMPING FACTOR: - the ratio of any one amplitude and the next succeeding it in the same sense or direction, when energy is not supplied on each cycle. In second order systems with a single degree of freedom, the decrement is constant. The amplitude decays as e-at where t=time, a=logarithmic decrement, and e=base of natural logarithms.
DAMPING RATIO: - the ratio of actual damping to critical damping. It can be expressed as the ratio of output under static conditions to twice the output at the lowest frequency where a 90-degree shift is observed. Pertains to measurement devices such as transducers.
ERROR BAND: - an error value, usually expressed in percentage of full scale output, which defines the maximum allowable error permitted for a specified combination of parameters.    Pertains to measurement devices such as transducers.
GAGE FACTOR: - a measure of the transfer function of strain-sensitive resistive materials incorporated into measurement transducers. Can be expressed as GF=((delta R)/(total R))/((delta L)/(total L)) where delta R is the change in resistance during the measurement process with total R being the original resistance of the gage. Delta L is the corresponding change in length of the sensor and total L is the length prior to measurement. Also called gage sensitivity.
INDUCTIVE TRANSDUCER: - a transducer in which the stimulus information is conveyed by means of changes in inductance.
INTEGRATING ACCELEROMETER: - a transducer designed to measure velocity by means of a time integration of acceleration.
MASS: - mass is a property of matter which has inertia. When used with regard to accelerometers, the term mass is frequently used as an abbreviation of seismic mass.
MULTIPLEXING: - the simultaneous transmission of two or more signals within a single channel. The three basic methods of multiplexing involve the separation of signals by time division, frequency division and phase division.
NONLINEARITY: - the difference between the actual instrument output and the expected output as defined by a reference straight line. It may be calculated as deviation from the straight line of the ascending cycle of calibration or on both the ascending and descending applications of stimulus.
NULL: - pertaining to a condition of balance in a device or system which results in zero output.
NULL DETECTOR: - an apparatus employed to sense the complete balance, or zero output condition, of a system or device.
OSCILLATING TRANSDUCER: - a transducer in which information characterizing the stimulus is provided in the form of deviation from the center frequency of an oscillator.
RESONANT FREQUENCY: - the frequency at which a given system or object will respond with maximum amplitude when driven by an external sinusoidal force of constant amplitude.
STRAIN GAGE: - an element or group of elements which change their resistivity as a function of applied stresses. When used with a force-summing member it is termed a strain gage transducer.
TELEMETERING: - a measurement obtained with the aid of intermediate methods which allows sensing, recording and interpretation of data at remote distances form the primary sensing devices. Usually done by high speed radio link.