@online {142,
	title = {Active mines and mineral plants in the US},
	publisher = {USGS},
	abstract = {Mine plants and operations for commodities monitored by the National Minerals Information Center of the USGS. Operations included are those considered active in 2003 and surveyed by the USGS.},
	keywords = {$\#$MapsDataPublications, $\#$MineralResources, active, collecting, dimension stone, economic geology, gold, lead, minerals, mines, quarries, sand and gravel, sand pits, silver},
	url = {http://tin.er.usgs.gov/mineplant/}
}
