Mining Terminology H - L

• High grade: Rich ore

• Hoist: The machine that is used for raising and lowering the cage or other conveyance in a shaft.

• Horse: A mass of waste rock that lies inside a vein or ore body.

• Horst: An up faulted block of rock.

• Host rock: The rock that surrounds an ore deposit.

• Hydrometallurgy: The treatment of ore through wet techniques like that of leaching, that results in the solution of a metal and its succeeding recovery.

• Hydrothermal : Having to do with hot liquids or fluids that are in the crust of the earth.

• Leachable: Can be extracted by chemical solvents.

• Leaching: Consists of a chemical process that is done to extract precious or valuable minerals from the ore and is also a natural process by which ground waters dissolve minerals, as a result leaving the rock with a smaller amount of some of the minerals than it originally had.

• Lens: In general used to describe a body of ore that is thick in the middle and tapers in the direction of the end.

• Lenticular: consists of a deposit that roughly has the form of a double convex lens.

• Level: The straight openings on a working horizon in a mine. It is usual to work mines from a shaft, setting up levels at standard intervals, in most cases around fifty meter or more apart.

• Lignite: A soft, brownish to black coal.

• Limestone: Consists of a bedded, sedimentary deposit that mostly consists of calcium carbonate.

• Limonite: Consists of a brown, hydrous iron oxide.