Acid mine drainage      Acidic run-off water from mine waste dumps and mill tailings ponds containing sulphide minerals. Also refers to ground water pumped to surface from mines. Such drainage often requires treatment to buffer acidity before it can be released into the natural environment.

Acid mine water      Mine water that contains free sulfuric acid, mainly due to the weathering of iron pyrites.

Acidic precipitation      Snow and rain that have a low pH, caused by sulphur dioxide and nitric oxide gases from industrial activity released into the atmosphere.

Acidic rocks      Usually refers to an igneous rock carrying a high (greater than 65%) proportion of silica.

Active workings      Any place in a mine where miners are normally required to work or travel and which are ventilated and inspected regularly.

Adit      An adit is a more or less horizontal drive (walk-in mine) into a hill that is usually driven for the purpose of intersecting or mining an ore body. An adit may also be driven into a hill to intersect or connect a shaft for the purpose of dewatering. Adits were commonly driven on a slight incline to enable loaded mine trucks to have the advantage of a downhill run out, while the empty (lighter) truck was pushed uphill back into the hill. The incline also allows water to drain out of the adit. An adit only becomes a tunnel if it comes out again on the hill somewhere, like a train tunnel.

Advance      Mining in the same direction, or order of sequence; first mining as distinguished from retreat. Or a noun describing the distance a tunnel has advanced during a period of time. For example, the advance in the tunnel last month was 100 metres.

Aerial magnetometer      An instrument used to measure magnetic field strength from an airplane.

Agglomerate      A breccia composed largely or entirely of fragments of volcanic rocks.

Agglomeration      A method of concentrating valuable minerals based on their adhesion properties.

Agitation      In metallurgy, the act or state of being stirred or shaken mechanically, some times accomplished by the introduction of compressed air.

Air Shaft      This term is one of the over used ones. There is a lot of effort in digging a mine. You don't do it if you don't have to. The airshaft is usually an abandoned shaft which has been intersected during the normal course of following the common denominator (usually a quartz vein) or driven a small distance to or along a vein to a known abandoned or disused shaft. An intersection provides ventilation. Two entrances to the surface provide a natural airflow, hence the term airshaft.

Air split      The division of a current of air into two or more parts.

Airborne survey      A survey made from an air craft to obtain photographs, or measure magnetic properties, radioactivity, etc.

Airway      Any passage through which air is carried. Also known as an air course.

Alloy      A compound of two or more metals.

Alluvial, alluvium      Relatively recent deposits of sedimentary material laid down in river beds, flood plains, lakes, or at the base of mountain slopes.

Alpha meter      An instrument used to measure positively charged particles emitted by radio active materials.

Alpha ray      A positively charged particle emitted by certain radioactive materials.

Alteration      Any physical or chemical change in a rock or mineral subsequent to its formation. Milder and more localized than metamorphism.

Amalgam      An alloy or union of mercury with another metal; gold or other metal that has been coated with mercury by adhesion More Information:

www.mininglife.com/commodities/mercury.htm     www.mininglife.com/metallurgist/amalgamation.htm  

Amalgamation      The process of removing precious metals from ores by use of mercury.

More Information: www.mininglife.com/commodities/mercury.htm     www.mininglife.com/metallurgist/amalgamation.htm  

Amorphous      A term applied to rocks or minerals that possess no definite crystal structure or form, such as amorphous carbon.

Amortization      The gradual and systematic writing off of a balance in an account over an appropriate period.

Analysis      The determination of the contents in any substance.

Anemometer      Instrument for measuring air velocity.

ANFO      Acronym for ammonium nitrate and fuel oil, a mixture used as a blasting agent in many mines.

Angle of draw      In coal mine subsidence, this angle is assumed to bisect the angle between the vertical and the angle of repose of the material and is 20° for flat seams. For dipping seams, the angle of break increases, being 35.8° from the vertical for a 40° dip. The main break occurs over the seam at an angle from the vertical equal to half the dip.

Angle of repose      The maximum angle from horizontal at which a given material will rest on a given surface without sliding or rolling.

Anhydrous      Refers to compounds having no water in their composition.

Anneal      Heating and cooling metals to make them harder and stronger

Annual report      The formal financial statements and report on operations issued by a corporation to its shareholders after its fiscal year-end.

Anode      A rectangular plate of metal cast in a shape suitable for refining by the electrolytic process.

Anomaly      Any departure from the norm which may indicate the presence of mineralization in the underlying bedrock. In geophysics and geochemistry, an area where the property being measured is significantly higher or lower than the larger, surrounding area.

Anthracite      A hard, black coal containing a high percentage of fixed carbon and a low percentage of volatile matter.

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 surface or its nearest point to the surface.

Appalachian Region      The eastern geological region of Canada consisting of the Appalachian Mountains

Aqua Regia      Acid mixture of 3 parts hydrochloric and 1 part nitric acid.

Aqueous      Containing water or related to material deposited by water.

Aquifer      A water-bearing bed of porous rock, often sandstone.

Arborescent      Minerals that branch in treelike forms.

Archean      Refers to rock group of the Archean geological era.

Arching      Fracture processes around a mine opening, leading to stabilization by an arching effect.

Argentiferous      Pertains to silver-clearing rocks.

Argentite      A silver sulphide mineral.

Argillaceous      Consisting of clays or having a clayey nature

Arrastra      Crude stone mill for grinding and amalgamating gold ores.

Arsenical      Pertaining to or containing arsenic

Artesian      an aquifer or water bearing zone where the piezometric surface (pressure level) is above ground surface.

Artificial intelligence      A field of computer science research aimed at enabling computers to mimic (at best) the reasoning processes of human experts.

Ash      The inorganic residue remaining after ignition of coal.

Assay      A chemical test performed on a sample of ores or minerals to determine the amount of valuable metals contained.

Assay - ton      Assaying equivalent ton, equal to 29.166 grams.

Assay foot (metre, inch, centimetre)      The assay value multiplied by the number of feet, metres, inches, centimetres across which the sample is taken.

Assay laboratory      A laboratory in which the proportions of metal in ores or concentrates are determined using analytical techniques

Assay map      Plan view of an area indicating assay values and locations of all samples taken on the property.

Assay Value      The value of an ore as determined by assay results; the amount and worth of metals or minerals in a sample.

Assessment work      The amount of work, specified by provincial law, that must be performed each year in order to retain legal control of mining claims.

Atomic Weight      The relative weight of an atom of an element as compared to the most stable isotope of carbon (At. Wt. 12.01115).

Attrition      Loss of material through friction and abrasion.

Auger      A rotary drill that uses a screw device to penetrate, break, and then transport the drilled material (coal).

Auriferous      Refers to gold-bearing rocks and gravels.

Auriferous      Containing gold.

Authorized capital      see Capital stock.

Autogenous grinding      The process of grinding ore in a rotating cylinder, using as a grinding medium large pieces or pebbles of the ore being ground, instead of conventional steel balls or rods.

Automation      The process of controlling industrial production processes by computers or programmable "logic-controllers" with a minimum of human involvement.

Auxiliary operations      All activities supportive of but not contributing directly to mining.

Auxiliary ventilation      Portion of main ventilating current directed to face of dead end entry by means of an auxiliary fan and tubing.

Avoirdupois      Common system of weights used in the U.S. and Britain.

Azimuth      A surveying term that references the angle measured clockwise from any meridian (the established line of reference). The bearing is used to designate direction. The bearing of a line is the acute horizontal angle between the meridian and the line.