Mining Glossary B

Back - The ceiling or roof of an underground opening.

Backfill - Waste material used to fill the void created by mining an orebody.

Background - Minor amounts of radioactivity due not to abnormal amounts of radioactive minerals nearby, but to cosmic rays and minor residual radioactivity in the vicinity.

Back sample - Rock chips collected from the roof or back of an underground opening for the purpose of determining grade.

Backwardation - A situation when the cash or spot price of a metal stands at a premium over the price of the metal for delivery at a forward date.

Balance sheet - A formal statement of the financial position of a company on a particular day, normally presented to shareholders once a year.

Ball mill - A steel cylinder filled with steel balls into which crushed ore is fed. The ball mill is rotated, causing the balls to cascade and grind the ore.

Banded iron formation – a bedded deposit of iron minerals.

Basolt - An extrusive volcanic rock composed primarily of plagioclase, pyroxene and some olivine.

Basal till - Unsorted glacial debris at the base of the soil column where it comes into contact with the bedrock below.

Basement rocks - The underlying or older rock mass. Often refers to rocks of Precambrian age which may be covered by younger rocks.

Base camp - Centre of operations from which exploration activity is conducted.

Base metal - Any non-precious metal (eg. copper, lead, zinc, nickel, etc.)

Basic rocks - Igneous rocks that are relatively low in silica and composed mostly of dark-colored minerals.

Batholith - A large mass of igneous rock extending to great depth with its upper portion dome-like in shape. Similar, smaller masses of igneous rocks are known as bosses or plugs.

Bauxite – a rock made up of hydrous aluminum oxides; the most common aluminum ore.

Bear market - Term used to describe market conditions when share prices are declining.The arrangement of sedimentary rocks in layers.

Bedding – the arrangement of sedimentary rocks in layers.

Beneficiate - To concentrate or enrich; often applied to the preparation of iron ore for smelting.

Bentonite - clay with great ability to absorb water and which swells accordingly.

Bessemer - An iron ore with very low phosphorus content.

Bio-leaching - A process for recovering metals from low-grade ores by dissolving them in solution, the dissolution being aided by bacterial action.

Biotite - platy magnesium-iron mica, common in igneous rocks.

Bit - The cutting end of a drill frequently made of an extremely hard material such as industrial diamonds or tungsten carbide.

Blackjack - A miner's term for sphalerite (zinc sulphide).

Black smoker - Volcanic vent found in areas of active ocean floor spreading, through which sulphide-laden fluids escape.

Blaster - A mine employee responsible for loading, priming and detonating blastholes.

Blast furnace - A reaction vessel in which mixed charges of oxide ores, fluxes and fuels are blown with a continuous blast of hot air and oxygen-enriched air for the chemical reduction of metals to their metallic state.

Blasthole - A drill hole in a mine that is filled with explosives in order to blast loose a quantity of rock.

Blister copper - A crude form of copper (assaying about 99%) produced in a smelter, which requires further refining before being used for industrial purposes.

Block caving - An inexpensive method of mining in which large blocks of ore are undercut causing the ore to break or cave under its own weight.

Board lot – One hundred shares.

Bond - An agreement to pay a certain amount of interest over a given period of time.

Boom - A telescoping, hydraulically powered steel arm on which drifters, manbaskets and hydraulic hammers are mounted.

Box hole - A short raise or opening driven above a drift for the purpose of drawing ore from a stope, or to permit access.

Break - Loosely used to describe a large-scale regional shear zone or structural fault.

Breast - A working face in a mine usually restricted to a stope.

Breccia - A rock in which angular fragments are surrounded by a mass of fine-grained minerals.

Broken reserves - The ore in a mine which has been broken by blasting but which has not yet been transported to surface.

Brunton compass - A pocket compass equipped with sights and a reflector, used for sighting lines, measuring dip and carrying out preliminary surveys.

Bulk mining - Any large-scale, mechanized method of mining involving many thousands of tonnes of ore being brought to surface per day.

Bulk sample - A large sample of mineralized rock, frequently hundreds of tonnes, selected in such a manner as to be representative of the potential orebody being sampled.Used to determine metallurgical characteristics.

Bullion - Metal formed into bars or ingots.

Bull market - Term used to describe financial market conditions when share prices are going up.

Bull quartz - A prospector's term for white, coarse-grained, barren quartz.

Byproduct - A secondary metal or mineral product recovered in the milling process.