Control of pit-lake water chemistry by secondary minerals, Summer Camp pit, Getchell mine, Nevada

At the Summer Camp pit of the Getchell mine in northern Nevada, the sulfate mineralogy is complex and includes gypsum, jarosite, pickeringite-halotrichite, copiapite, melanterite, langite, and bukovskyite that occur along with scorodite-mansfieldite and Ca-Cu-Zn arsenate minerals. Leaching of these minerals by meteoric water seasonally contributes As, Fe, Ca, trace metals, sulfate, and hydrogen ions to the lake. During the early stages of pit-lake refilling (1991-1993), this mechanism had an important control on water quality in the pit, although over time the effect has lessened as groundwater inflow has increased the lake volume and diminished the relative importance of wall rock leachate. The formation and reaction of secondary minerals around pit lakes in net evaporative environments are both a source and sink for metals.