Mining is the extraction of valuable minerals or other geological materials from the earth, usually from an ore body, lode, vein, seam, reef or placer deposit. These deposits form a mineralized package that is of economic interest to the miner.
Ores recovered by mining include metals, coal, oil shale, gemstones, limestone, chalk, dimension stone, rock salt, potash, gravel, and clay. Mining is required to obtain any material that cannot be grown through agricultural processes, or feasibly 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.
Mining of stones and metal has been a human activity since pre-historic times. Modern mining processes involve prospecting for ore bodies, analysis of the profit potential of a proposed mine, extraction of the desired materials, and final reclamation of the land after the mine is closed. De Re Metallica, Georgius Agricola, 1550, Book I, Para. 1
Mining operations usually create a negative environmental impact, both during the mining activity and after the mine has closed. 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.
Levels of metals recycling are generally low. Unless future end-of-life recycling rates are stepped up, some rare metals may become unavailable for use in a variety of consumer products. Due to the low recycling rates, some landfills now contain higher concentrations of metal than mines themselves.
The California Gold Rush
(1848–1855) began on January 24, 1848, when gold
was discovered by James Wilson Marshall
at Sutter's Mill
, in Coloma
, California. News of the discovery soon spread, resulting in some 300,000 men, women, and children coming to California
from the rest of the United States
and abroad. Of the 300,000, approximately 150,000 arrived by sea while the remaining 150,000 arrived by land.
These early gold-seekers, called "40-niners," (as a reference to 1849) traveled to California by sailing boat and in covered wagons across the continent, often facing substantial hardships on the trip. While most of the newly-arrived were Americans, the Gold Rush attracted tens of thousands from Latin America, Europe, Australia, and Asia. At first, the prospectors retrieved the gold from streams and riverbeds using simple techniques, such as panning. More sophisticated methods of gold recovery developed which were later adopted around the world. At its peak, technological advances reached a point where significant financing was required - increasing the proportion of corporate to individual miners. Gold, worth billions of today's dollars, was recovered, which led to great wealth for a few. However, many returned home with little more than they started with.
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Mining transport in Devnya, Bulgaria.
A Bucyrus Erie 2570 dragline and CAT 797 haul truck at the North Antelope Rochelle opencut coal mine
View showing miners' clothes suspended by pulleys, also wash basins and ventilation system, Kirkland Lake, Ontario, 1936.
Mantrip used for transporting miners within an underground mine
Iron hydroxide precipitate stains a stream receiving acid drainage from surface coal mining.
Simplified world active mining map
Gallery, 12th to 13th century, Germany
Caterpillar Highwall Miner HW300 – Technology Bridging Underground and Open Pit Mining
Sulfur miner with 90 kg of sulfur carried from the floor of the Ijen Volcano (2015)
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