Coalfield
There are many coal-slag heaps (small mountain made by coal slag) aound abandoned coal mines not only in Japan. We have to consider the revegetation.
Coalfield in Hokkaido
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| Distribution of coalfields in Hokkaido, Japan (Hokkaido Government 1993) |
Now, there are only one company mines coal in eastern Hokkaido (except minor mining).
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| Mikasa (July, 19, 2003). A coal-slag heap showed low vegetation cover. A residential talked that the heap had almost no vegetation cover a couple of years before now. | Bibai (July, 20, 2003). Coal-mining Memorial Park. | Bibai. Close to Coal-mining Memorial Park. The black part is coal. |
Terminology
Acid mine drainage |
Water mixed with sulfuric acid and having a pH of < 6.0, due to minerals containing sulfides, etc. The sulfuric acid mixes with water and flows out of the mine into surrounding areas as acid mine drainage. |
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Adit |
A horizontal entrance to go an underground mine |
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Dump |
A pile or heap of waste rocks, etc. |
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Gangue |
Low-valuable minerals. |
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Gob |
Rock or other coarse materials sorted out of coal either during mining or processing. |
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Hard rock mine |
Mining metallic minerals, e.g., copper, lead, zinc, silver, and gold. The mining is undertaken to rocks that require drilling and blasting to extract the ore. |
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Heap leaching |
A process whereby valuable metals, e.g., gold, silver, and copper, are leached from a heap of crushed ore by solutions percolating down through the heap. |
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Impoundment |
A natural or artificial, closed basin that is dammed or excavated for retaining water, sediment and/or waste. |
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Leachate |
Liquid that has percolated through a medium, and has extracted dissolved or suspended materials from it. |
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Mill |
A mineral processing facility for grinding, pulverizing, and extracting metals and/or producing a product. |
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Mining |
The process to obtain useful minerals from the underground and surface of earth. |
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Open pit mining |
A type of surface mining used to extract belowground metallic mineral deposits. |
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Ore processing |
Milling, heap leaching, flotation, vat leaching, adn/or other standard hard-rock mineral concentration processes. |
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Pitting |
Making shallow pits and/or basins to reduce overland flow. (Also used for seedbed.) |
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Processed mined materials |
The materials remaining after the valuable minerals have been removed from the ore. |
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Scalping |
Removal of vegetation before mining. |
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Shaft |
A vertical entrance to an underground mine. |
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Slag |
When smelting is done, The non-metallic materials float on top of the heavier metallic constituents in the molten state, and remains in that position when it cools and hardens |
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Smelting |
The chemical reduction of a metal from its ore and certain fluxes by melting at high temperatures. |
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Spoil |
Overburden material disturbed or removed from its natural state, or non-ore material removed in gaining access to the ore or mineral material during the mining process. Spoil is specific to coal mining and overburden to more specific to hard rock mining. |
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Waste rock dump |
Waste rock that was mined and then was disposed. |
References
- Hokkaido Government. 1993. Coal in Hokkaido. Hokkaido Government, Sapporo. pp. 428 (+ 10 figure plates). (In Japanese)
- Vegetation dynamics after mining (鉱山跡地における植物群集動態)