Relief shown by spot heights.
"Base from U.S. Geological Survey."
"Sources of information: Colorado Department of Natural Resources-Division of Mines and Mined Land Reclamation Division; U.S. Mine Safety and Health Administration; mining companies."
Includes alphabetical and by county indexes of mines and mills or plants.
"Acknowledgment: Research supported by U.S. Geological Survey, Department of the Interior, under U.S.G.S. Agreement no. 14-08-001-AO-154."
Description based on record for print version.
