The treatment of mined material, making it more concentrated or richer.

Specialized chemical or electronic instruments used to detect mine gases.

Blending of a gas and air, resulting in a homogeneous mixture. Blending of two or more gases.

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 weig [..]

made sources, primarily emissions of sulfur and nitrogen oxides resulting from fossil fuel combustion.

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

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

A nearly horizontal passage from the surface by which a mine is entered and dewatered. A blind horizontal opening into a mountain, with only one entrance.

Mining in the same direction, or order of sequence; first mining as distinguished from retreat.

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