Saturday

Template - Mining Terms

Mines are dug to follow an externally visible vein of ore into a formation such as a hill or mountain side. Piles of waste rock outside a mine containing no precious ores are called tailings.
                        
ADIT: An ADIT is a horizontal mine feature, usually dug into the side of a hill or mountain. The top (ceiling) of an adit is called the Back. The sides of an adit are called the Ribs. If an adit is open at both ends, it becomes a tunnel.
COLLAR: A COLLAR is the point of entry to a shaft. It most often has a wooden frame around it to keep the edges from caving in.
CONCENTRATION MILL:    Concentrators concentrate ore. Example; Ore of, say, half ounce of gold and twelve ounces of silver per ton might be concentrated to 2.5 ounces of gold and 60 ounces of silver per ton of concentrates - the value increased per ton, by a factor of five. This was done to save on freight costs.
CROSSCUT: Is a passageway that is used to connect drifts and stopes.
DRIFT: A near-horizontal secondary passageway that is connested to a shaft, or an adit. Drifts usually follow the ore vein.
GRIZZLY: A grating of iron or steel bars for screening ore.
HEADFRAME: A large wooden frame which supports the cable and bucket or cgae when hoisting ore. A structure over a mine shaft which holds a pulley for the steel cable that raises and lowers the skip in the mine shaft.
HOIST: An engine for raising ore and water from a mine and for lowering and raising men, material and machinery utilizing a drum and steel cable - usually connected to a Headframe.
JAW CRUSHER: A machine for reducing the size of materials by impact or crushing between a fixed plate and an oscillating plate, or between two oscillating plates, (forming a tapered jaw) before sending the ore through a stamp mill.
LODE: A fissure or vein in rock filled with minerals, a vein producing valuable metallic ore between definite boundaries, as in the Mother Lode.
MILLING: The process of dressing ore by crushing, stamping, amalgamation, leaching, etc. to separate the gold from the base rock.
MINE: The further development of a prospect that creates a more expansive shaft or adit into the earth for the excavation of valuable minerals or ubstances.
MUCK: The rock pile resulting from blasting. Miners shoveling the muck were muckers.
ORE SKIP: The cage, or basket, that carries the ore to the surface.
OVERBURDEN: The leftover ore from a strip mining operation.
PORTAL: The opening to an adit or tunnel is called a portal, which is sometimes framed with wooden timbers.
PROSPECT: The exploration of a property suspected of containing a potentially economic mineralization/deposit that may be worth the expense of additional mining. Usually a small, hand dug shaft or adit. A successful prospect is developed into a mine.
RAISE: A vertical, or inclined passageway, driven at an upward angle. A mine shaft driven upward from a level to connect with the level above, or to explore the ground for a limited distance above one level. After two levels are connected, the connection may be a winze or a raise, depending upon which level is taken as the point of reference.
SHAFT: A SHAFT is a vertical mine feature. Miners often dug directly down to follow the ore vein. The opening to a shaft is called the collar. A SUMP is a continuation of a shaft with the purpose of collecting water and preventing flooding by weather or ground seepage.
STAMP MILL: A stamp is a pestle that is raised by some form of power, typically water or steam. Gravity causes the stamp to drop, crushing ore placed between the stamp's shoe and the die. A common pattern in stamp mill design was to use five stamps in a battery. This set up used a tappet at the top and the stamp was lifted and dropped by the revolving cam engaging the underside of the tappet. A machine, and the building containing it, in which crushed rock is crushed even smaller by descending rods with stamp shoes, usually lifted and dropped by a cam, and operated by water power, steam power or later on by electric motor. Usually arranged in groups of five, each stamp weighed up to 2000 pounds and dropped 6 to 8 inches. Each stamp battery dropped up to 100 times per minute, and could be heard for miles. Amalgamation was usually combined with the crushing when gold or silver ore was processed.
STOPE: The portion of the mine being currently worked. They can follow a vein in every direction, from narrow passageways to huge caverns; any excavation in a mine, other than development workings, made for the purpose of extracting ore. The outlines of the ore body determine the outlines of the stope. If an adit or drift is successful in following a vein to a large ore body, a STOPE will be made by removing all the available ore. The result can resemble a cavern. Larger stopes are often referred to as ballrooms.  A stope that breaches the surface becomes an OPEN STOPE.
STRIP MINING: Strip mining is the practice of mining a seam of mineral, by first removing a long strip of overlying soil and rock (the overburden). "Contour stripping" involves removing the overburden above the mineral seam near the outcrop in hilly terrain, where the mineral outcrop usually follows the contour of the land. Contour stripping is often followed by auger mining into the hillside, to remove more of the mineral. This method commonly leaves behind terraces in mountainsides.
SURFACE MINING: Surface mining, including strip mining, open-pit mining and mountaintop removal mining, is a broad category of mining in which soil and rock overlying the mineral deposit (the overburden) are removed. It is the opposite of underground mining, in which the overlying rock is left in place, and the mineral removed through shafts or tunnels.
TAILINGS: The waste material left after ore has been crushed and the desired mineral removed. At first dumped near the mine entrance, after 1914 the Kennedy Mine used large tailing wheels to move the mine tailings to an impound dam away from the mill site.
WHIM: A method of hoisting ore using a horse, and usually two men, pulling a wire rope over a pulley and down into the shaft. This method is a more robust hoisting method than whip method.
WHIP: A method of hoisting ore using a horse, or man, pulling a rope that went over a pulley and down into the shaft.
WINZE: A winze is a shaft dug within an adit or drift to explore the lower levels of ground beneath the original vein. A vertical, or inclined passageway, driven at a downward angle. A vertical opening driven downward connecting two levels in a mine. When one is standing at the top of a completed connection the opening is referred to as a winze, while when standing at the bottom, the opening is a raise, or rise.