APES Ch. 15 Vocab

High grade ore

Contains fairly large amount of desired material

Low grade ore

Contains smaller amount of desired material

Mineral

Element or inorganic compound that occurs naturally and is solid with a regular internal crystalline structure. Ex: salt, quartz

Economic depletion

Exhaustion of 80% of the estimated supply of a nonrenewable resource. Finding, extracting, and processing the remaining 20% usually costs more than it is worth. May also apply to the depletion of a renewable resource, such as a fish or tree species.

Subsurface mining

Extraction of a metal ore or fuel resource such as coal from a deep underground deposit.

Ingenuous rock

Forms below the earth's surface when magma wells up from the earth's upper mantle, cools, and hardens. Ex: granite, lava rock

Metamorphic rock

Forms when a preexisting rock is subjected to high temperatures, high pressures, chemically active fluids, or combo. Transform rock by reshaping internal crystalline structure and its physical properties and appearance. Ex: anthracite, slate, marble

Overburden

Layer of soil and rock overlying a mineral deposit; removed by surface mining

Heap-leach extraction

Mining process to extract precious metals and copper compounds from ore; mined ore is placed in a heap and any precious metals are slowly leached

Acid mine drainage

Occurs when rainwater seeping through a mine or mine wastes carries sulfuric acid to nearby streams and groundwater. Contaminates water supply and destroys some forms of aquatic life

Ore

Part of metal-yielding mineral that can be economically and legally extracted at a given time.

Spoil banks

Piles of waste rock produced by surface mining.

Smelting

Process in which a desired metal is separated from other elements in an ore mineral

Open-pit mining

Removing minerals such as gravel, sand, metal ores by digging them out of the earth's surface and leaving them an open pit behind

Surface mining

Removing soil, subsoil, and other strata and then extracting a mineral deposit found fairly close to the earth's surface.

Surface Mining Control and Reclamation Act

Requires mining companies to restore most surface-mined land by grading and replanting it; only partially successful

Reserves

Resources that have been identified and from which a usable mineral can be extracted profitably at present prices with current technology

Tailings

Rock and other waste materials removed as impurities when waste mineral material is separated from the metal in an ore.

Sedimentary rock

Rock that forms from the accumulated products of erosion and in some cases from the compacted shells, skeletons, and remains of dead organisms

Subsidence

Slow or rapid sinking of part of the earth's crust that is not slope-related

Contour strip mining

Surface mining; used on hilly, mountainous terrain. Power shovel cuts terraces on side of hill-->earthmover removes overburden-->power shovel extracts coal. Overburden from each terrace dumped onto one below

Area strip mining

Surface mining; used when terrain is flat. Earthmover strips away overburden and power shovel digs a cut to remove mineral deposit-->trench filled with overburden and new cut made parallel to previous one

Mountaintop removal

Surface mining; uses explosives, shovels, and machinery to remove tip remove mountaintop to expose seams of coal underneath a mountain

Depletion time

The time it takes to use a certain fraction, usually 80%, of the known or estimated supply of a nonrenewable resource at an assumed rate of use. Finding and extracting the remaining 20% usually costs more than it is worth.

Gangue

The waste material left over from the mining process after the desired metal is extracted

Dredging

Type of surface mining in which chain buckets and draglines scrape up sand, gravel, and other surface deposits covered with water. It is also used to remove sediment from streams and harbors to maintain shipping channels.

Mineral Law of 1872

Under law, person or corp. can file a mining claim or assume legal ownership over almost any US public land. Designed to encourage mining of hardrock minerals on US public lands and to develop the then-sparsely populated West.

Spoils

Unwanted rock and other waste materials produced wen a material is removed from the earth's surface or subsurface

Highwall

Wall of dirt left in front of a highly erodible bank of soil and rock