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Ores recovered by mining include metals, coal, oil shale, gemstones, limestone, chalk, dimension stone, rock salt, potash, gravel, and clay.

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Hence, most of the world's nations have passed regulations to decrease the impact.Work safety has long been a concern as well, and modern practices have significantly improved safety in mines. Unless future end-of-life recycling rates are stepped up, some rare metals may become unavailable for use in a variety of consumer products.Mining is extraction of valuable minerals or other geological materials from the earth usually from an orebody, lode, vein, seam, reef or placer deposits.These deposits form a mineralized package that is of economic interest to the miner.They built numerous aqueducts to supply water to the minehead.

There, the water stored in large reservoirs and tanks.

When a full tank was opened, the flood of water sluiced away the overburden to expose the bedrock underneath and any gold veins.

The rock was then worked upon by fire-setting to heat the rock, which would be quenched with a stream of water.

The water was used for a variety of purposes, including removing overburden and rock debris, called hydraulic mining, as well as washing comminuted, or crushed, ores and driving simple machinery.

The Romans used hydraulic mining methods on a large scale to prospect for the veins of ore, especially a now-obsolete form of mining known as hushing.

The miners crushed the ore and ground it to a fine powder before washing the powder for the gold dust. Examples include the silver mines of Laurium, which helped support the Greek city state of Athens.