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Mining is required to obtain any material that cannot be grown through agricultural processes, or created artificially in a laboratory or factory.
Mining in a wider sense includes extraction of any non-renewable resource such as petroleum, natural gas, or even water.
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 methods had been developed by the Romans in Spain in 25 AD to exploit large alluvial gold deposits, the largest site being at Las Medulas, where seven long aqueducts tapped local rivers and sluiced the deposits.
There, the water stored in large reservoirs and tanks.
Due to the low recycling rates, some landfills now contain higher concentrations of metal than mines themselves.
Since the beginning of civilization, people have used stone, ceramics and, later, metals found close to the Earth's surface.
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.