Mineralogical and geochemical investigations of pyrite-rich mine waste from a kyanite mine in Central Virginia with comments on recycling

A pyrite-rich waste stream is one of three types generated from a kyanite mine in central Virginia near the town of Dillwyn, Buckingham County. Currently, ore consists of approximately 3% pyrite waste and an estimated 382,000 tons of this waste stream has been generated over the past 60 years. The mineralogy of the waste stream consists of variable amounts of pyrite (70–>99%), talc (1–20%), quartz (1–10%), kyanite (0.5–5%) with minor or trace amounts of magnetite, hematite, galena, anorthite and rare earth phosphate. Energy dispersive spectroscopy analysis indicates that talc has minor amounts of Al up to 1.57 wt% and Fe up to 4.29 wt% and pyrite grains have no impurities above detection limit of approximately 0.1 wt%. Bulk chemical analysis of selected elements using inductively coupled plasma-mass spectrometry analysis indicate that Zn (28.82–367.71 ppm), As (8.94–18.26 ppm), Se (44.62–64.50 ppm), Cd (0.19–1.03 ppm), Hg (0.87–35.91 ppm), and Pb (65.10–189.66 ppm) occur at levels of some environmental concern. Au and Ag concentrations are negligible. Currently the waste stream is well managed and sold, but for a low price. Talc is of sufficient quality to be of interest for recycling but the estimated 540 tons generated per year is not a suitable quantity to be economically viable. Currently, the waste stream is not viable for recycling for higher monetary value; however, the characteristics of the pyrite may enable such recycling in the future for solar energy technologies. This and other associated waste streams show long term promise for integrated recycling and may play important economic roles in an economically disadvantaged region.