A rock made up of hydrous aluminum oxides; the most common aluminum ore. Bear market

Acid -

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

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. Activated carbon (charcoal)

An opening driven horizontally into the side of a mountain or hill for providing access to a mineral deposit. Advanced property

An instrument used to measure magnetic field strength from an airplane. Aeromagnetic survey

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

In metallurgy, the act or state of being stirred or shaken mechanically, sometimes accomplished by the introduction of compressed air. Airborne survey

A compound of two or more metals. Alluvium

An instrument used to measure positively charged particles emitted by radioactive materials. Alpha ray