AN INITIAL X-RAY FLUORESCENCE, X-RAY DIFFRACTION AND REFLECTIVE SPECTROSCOPY INVESTIGATION OF MINE WASTE FROM TONOPAH, NEVADA

The City of Tonopah, Nevada is known for its silver mining past that produced over 5 million tons of ore as well as over 2 billion dollars of silver at current value while it was active. The evidence of this mining is apparent in the town where there are large piles of mine waste scattered throughout the city. Some of these mine waste piles have homes built on them outlining how integrated the mine waste is in the community. Findings from bulk sample XRF and limited SEM data showed that there are potentially harmful minerals and elements in the mine waste. The following elements where found, “n” represents the amount of times the element occurred in all the samples and the mean and range for each are provided: As (n = 12, mean = 0.006 wt%, range = 0.003 to 0.018 wt %), Ag (n = 4, mean = 0.119 wt%, range = 0.063 to 0.166 wt%), Cr (n = 21, mean = 0.783 wt%, range = 0.028 to 1.328 wt%), Cu (n = 20, mean = 0.050 wt%, range = 0.008 to 0.1992 wt%), Mo (n = 5, mean = 0.009 wt%, range = 0.002 to 0.019 wt%), Ni (n = 17, mean = 0.024 wt%, range = 0.001 to 0.155 wt%), Pb (n = 19, mean = 0.018 wt%, range = 0.001 to 0.084 wt%), Sb (n = 7, mean = 0.032 wt%, range = 0.003 to 0.094 wt%), V (n = 20, mean = 0.0128 wt%, range = 0.001 to 0.0371 wt%), Zn (n = 20, mean = 0.048 wt%, range = 0.010 to 0.1627 wt%). Preliminary scanning electron microscopy images and data correlate with these findings and images of lead, silver and pyrite have been obtained. Powder X-ray diffraction indicates that there is a wide range of minerals present in different types of mine waste, however pyrite and potentially oxides are the major controls on the distribution of elements of environmental concern. Many wastes are rich in quartz and others are rich in numerous other silicates. Reflective spectra show that different waste types can be classified and high-resolution mapping using UAVs should be possible. This work provides the foundation for more detailed environmental and applied mineralogical studies.