Just as agriculture was necessary to sustain the population of America, the products which came as a result of mining were just as necessary to the developing country. Immigrants seem to have been one of the major groups involved in mining because of the familiarity with the occupation or the need for quick employment. Many also pursued mining with a hope of "striking it rich" or simply to be able to provide for their families.
In any case, the value for the researcher is that there was a paper trail. As with other land applications, a mining claim required the claimant be twenty-one years of age and be a citizen of the United States or have made a declaration of intent to become a citizen. Along with that, after the California gold rush of 1848, the forms required by the government often included detailed questions such as a place of birth. For those with immigrant ancestors this information could break down the oceanic "brick wall."
The types of mining claims were either lode claims or placer claims. A lode claim is one which involves minerals found in rock veins such as tin, silver or gold. A placer claim is one with minerals not found in rock veins, but through means such as open pit mining or panning, for example.
When researching mineral claims, it is helpful to have know a little of when mines were formed and where they were located so that the researcher will have an idea as to whether or not the ancestor may have filed a mineral claim. It also adds to the history of ancestors as we learn more of why they moved to certain areas.
Chronology of Mining in the United States
1763 First coal mines in what is now Richmond, Virginia
1785 The government created a Land Ordinance which specified that one-third of all mineral lands were to be reserved for the United States.
1800 First production of coal in Ohio in Jefferson County. 
1807 Legislation provided for leasing of the mineral lands held by the government.
1847 Ducktown, Polk county, Tennessee began copper mining in 1847 and continued into the later 1900's.
1848 First Coal miner's union formed in Schuylkill county, Pennsylvania
1848 California gold rush
1863 First mining of copper in the Bingham Canyon mine (Kennecott Copper Mine)began.
1866 The government Act of 26 July 1866 provided for mining claimants to be able to obtain a patent for their mineral lands. The requirements for a patent for lode claims were that the claimant must have made a significant amount of improvement on the claim and must pay a certain amount per acre. By 1870, this included placer claims.
1873 Copper mining begins in Arizona in Clifton (Morenci), Arizona. Some of the other Arizona mines were in Jerome, Ajo, Bisbee and Globe. Arizona is one of the major copper producing states in the nation.
1872 The General Mining Law was established which defined mineral lands as those which held "any valuable minerals."
1879 First oil wells drilled in California
1879 Copper mining begins in Tyrone, Grant county, New Mexico and has become one of the top copper producing areas in the nation.
1880 Gold strike in Juneau, Alaska
1882 Copper discovered in the Butte, Montana area and it quickly became one of the leading copper producing areas in the United States.
1883 Coal mines in southern West Virginia attracted European immigrants and many African Americans. 
1887 First oil wells drilled in Texas
Mines in the United States
The largest Coal Producing States in 1889 were Pennsylvania, Illinois, Ohio, West Virginia, Iowa, Alabama, Indiana, Colorado, Kentucky, Kansas and Tennessee
For a more complete list of copper mines in the United States visit the Wikipedia article entitled: Copper mining in the United States
- Hone, Wade E. Land and Property Research in the United States Ancestry Incorporated, Salt Lake City, Utah, 1997
- Global InfoMine Mining in USA http://www.infomine.com/countries/SOIR/USA/ 1990-2010
- Crowell, Douglas L. Geofacts No. 14 Ohio Department of Natural Resources - Division of Geological Survey. History of Coal Mining in Ohio Revised May 2005
- Wapedia - Wiki: History of Coal Mining