A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

A

Abutment      In coal mining, (1) the weight of the rocks above a narrow roadway is transferred to the solid coal along the sides, which act as abutments of the arch of strata spanning the roadway; and (2) the weight of the rocks over a longwall face is transferred to the front abutment, that is, the solid coal ahead of the face and the back abutment, that is, the settled packs behind the face.

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.