Mining-Prospecting Dictionary

• Halide: A mineral compound characterized by a halogen such as fluorine, chlorine, iodine, or bromine as the anion.
• Hallmark: Mark, or marks, which indicate the producer of a gold bar and its number, fineness, etc.
• Hanging wall: Rock overlying an ore deposit. The overlying side of an orebody, fault, or mine working, esp. the wall rock above an inclined vein or fault
• Hardpan: Cemented or compacted gravels and clays.
• Head-frame: Structure erected over the mouth of a shaft.
• Heads: Value of an ore before being milled; also the ore itself.
• Heap: Pile of ore stacked for leaching.
• Heap leaching: Leaching of an ore pile with cyanide solution to extract the precious metal content. A process whereby gold is extracted by "heaping" broken ore on sloping impermeable pads and repeatedly spraying the heaps with a weak cyanide solution which dissolves the gold content. The gold laden solution is then collected for gold recovery.
• Heap Leach Pad: A large impermeable foundation or pad used as a base for ore during heap leaching.
• High-grade: Rich gravels; to mine richer portions of a deposit; also refers to stealing large pieces of gold or rich ores.
• Highgrading: Taking only richer ores.
• Hilch: Hole in rock to support timbers; also connecting objects together.
• Hoist: The machine used for raising and lowering the cage or other conveyance in a shaft.
• Homogeneous: Generally uniform throughout; well mixed.
• Horse: Chunk of worthless rock in an ore body.
• Horst: An elongated, relatively uplifted crustal unit or block that is bounded by faults on its long sides.
• Host Rock: The rock surrounding an ore deposit.
• Hydrated: Contains water in chemical combination.
• Hydraulic: Related to water in motion, especially under pressure. Also refers to force exerted by liquids under pressure, including oils.
• Hydrochloric acid: Acid composed of hydrogen and chlorine.
• Hydrographic Basins: One of the 260 Hydrographic Areas recognized within the Great Basin by the United States Geological Survey. These areas are used for management of water resources. The hydrographic areas are defined by watershed boundaries that generally correspond to geographic features.
• Hydrothermal: Of or pertaining to hot water, to the action of hot water, or to the products of this action, such as a mineral deposit precipitated from a hot aqueous solution, with or without demonstrable association with igneous processes; also, said of the solution itself.