Wall - the waste or country
rock on each side of a vein
Waste - That rock or mineral
which must be removed from a mine to keep the mining scheme practical, but which has no
value.
Water Gauge (standard U-tube)
- Instrument that measures differential pressures in inches of water.
Weathering - the alteration of
rock by such processes as the chemical action of air, water, plants and bacteria, and the
mechanical action of temperature change.
Wedge - A piece of wood
tapering to a thin edge and used for tightening in conventional timbering.
Weight - Fracturing and
lowering of the roof strata at the face as a result of mining operations, as in
"taking weight".
Width - The thickness of a
lode measured at right angles to the dip.
Winning - The excavation,
loading, and removal of coal or ore from the ground; winning follows development.
Winze - Inside a mine for the
purpose of connecting with a lower level or of exploring the ground for a limited depth
below a level.
Wire rope - A steel wire rope
used for winding in shafts and underground haulages. Wire ropes are made from medium
carbon steels. Various constructions of wire rope are designated by the number of strands
in the rope and the number of wires in each strand.
Working - When a n ore seam is
being squeezed by pressure from roof and floor, it emits creaking noises and is said to be
"working". This often serves as a warning to the miners that additional support
is needed.
Working face - Any place in a
mine where material is extracted during a mining cycle.
Working place - From the
outside of the last open crosscut to the face.
Workings - The entire system
of openings in a mine for the purpose of exploitation.
Working section - From the
faces to the point where coal is loaded onto belts or rail cars to begin its trip to the
outside.