Planks or small timbers placed between steel ribs along the roof of a stope or drift to prevent rocks from falling, rather than to support the main weight of the overlying rocks.

The electric cap lamp worn for visibility. Also, the flame safety lamp used in coal mines to detect methane gas concentrations and oxygen deficiency.

An igneous rock, composed of dark minerals, that occurs in dykes; sometimes contains diamonds.

Rocks in tropical climates weather to form laterite, a soft, deeply weathered mixture of oxide and hydroxide minerals and clays. Some metals may be leached by the weathering, but others - aluminum, iron and nickel - can stay behind as oxides or silicates. Laterites produce virtually all the world's aluminum ore and laterite nickel deposits are a significant source of the world's nickel.

A chute or trough for conveying pulp, water or powdered ore in a mill.

A general name for the molten rock ejected by volcanoes.

The design or pattern of the main roadways and workings. The proper layout of mine workings is the responsibility of the manager aided by the planning department.

Extractable by chemical solvents.

A chemical process for the extraction of valuable minerals from ore; also, a natural process by which ground waters dissolve minerals, thus leaving the rock with a smaller proportion of some of the minerals than it contained originally; see cyanidation

Generally used to describe a body of ore that is thick in the middle and tapers towards the ends.

A deposit having roughly the form of a double convex lens.

The horizontal openings on a working horizon in a mine; it is customary to work mines from a shaft, establishing levels at regular intervals, generally about 50 meters or more apart.

The use of borrowed money, also called "margin," to finance a corporation or a person's activities and trading. A mortgage, for example, is considered leverage.

There are many types of licenses, each of which dictates what can or cannot be done on a concession (see definition under C). For example, a company holding an oil exploration license cannot actually produce and market the oil until it has been switched to an exploitation or production license.

A soft, low-rank, brownish-black coal.

A bedded, sedimentary deposit consisting chiefly of calcium carbonate.

An order made by a client to a broker to buy or sell shares at a specified price or better.

A brown, hydrous iron oxide.

Straight clearings through the bush to permit sightings for geophysical and other surveys.

The character of a rock described in terms of its structure, color, mineral composition, grain size, and arrangement of its component parts; all those visible features that in the aggregate impart individuality of the rock. Lithology is the basis of correlation in coal mines and commonly is reliable over a distance of a few miles.

To place explosives in a drill hole. Also, to transfer broken material into a haulage device.

Transfer point at a shaft where bulk material is loaded by bin, hopper, and chute into a skip.

A mineral deposit in solid rock.

The process of recording geological observations of drill core either on paper or on computer disk.

The twice-daily bidding session held by five dealing companies to set the gold price. There are also daily London fixes to set the prices of other precious metals.

A major bidding market for base metals, which operates daily in London.

Securities owned outright or carried on margin.

2,240 lbs. avoirdupois (compared with a short ton, which is 2,000 lbs.).

Up to and including 660 volts by federal standards.