Mining Glossary F

Face - The end of a drift, crosscut or stope in which work is taking place.

Fault - A break in the Earth's crust caused by tectonic forces which have moved the rock on one side with respect to the other.

Feldspar - A group of common rock-forming minerals that includes microcline, orthoclase, plagioclase and others.

Felsic - Term used to describe light-colored rocks containing feldspar, feldspathoids and silica.

Ferrous - Containing iron.

Fine gold - Fineness is the proportion of pure gold or silver in jewelry or bullion expressed in parts per thousand. Thus, 925 fine gold indicates 925 parts out of 1,000, or 92.5% is pure gold.

Fissure - An extensive crack, break or fracture in rocks.

Fixed Assets - Possessions such as buildings, machinery and land which, as opposed to current assets, are unlikely to be converted into cash during the normal business cycle.

Float - Pieces of rock that have been broken off and moved from their original location by natural forces such as frost or glacial action.

Flotation - A milling process in which valuable mineral particles are induced to become attached to bubbles and float as others sink.

Flowsheet - An illustration showing the sequence of operations, step by step, by which ore is treated in a milling, concentration or smelting process.

Flow-through shares - Shares in an exploration company that allow the tax deduction or credits for mineral exploration to be passed to the investor.

Flux - A chemical substance that reacts with gangue minerals to form slags, which are liquid at furnace temperature and low enough in density to float on the molten bath of metal or matte. used in geophysics to measure total magnetic field.

Fluxgate magnetometer- an instrument used in geophysic to measure total magnetic field.

Fold - Any bending or wrinkling of rock strata.

Footwall - The rock on the underside of a vein or ore structure.

Forward contract - The sale or purchase of a commodity for delivery at a specified future date.

Fracture - A break in the rock, the opening of which allows mineral-bearing solutions to  enter.  A "cross-fracture" is a minor break extending at more-or-less right angles to the direction of the principal fractures.

Free milling - Ores of gold or silver from which the precious metals can be recovered by concentrating methods without resorting to pressure leaching or other chemical treatment.