Geochemical characterization and evaluation, mansfield canyon, wrightson mining district, santa rita mountains, arizona

摘要

Mansfield Canyon, of the Wrightson Mining District, Santa Cruz County, Coronado National Forest, Arizona, was actively mined in the later 1800's and early 1900's, with minor activity until 1953. The main products were lead, silver, copper, zinc, and gold occurring in polymetallic quartz viens. The canyon contains numerous aditis and waste dumps, some of which generate metal-loaded acid. Samples of seeps, waste dumps and bedrock have been collected for various analyses: metal concentrations, acid base accounting (ABA), and water quality to evaluate the extent of oxidation and metal release from the start of mining until present, the potential impact, and reclamation options. Although the waste-rock piles within the canyon are small (2,000-10,000 tons), they have a high sulfide content with little or no meutralizig capacity. It is planned, therefore, to move the waste piles wither to a constructed repository site within the canyon or to a copper leach facility to be used as an acid generator.