• Geophysical Surveys in the Lead Queen Mine Area, Patagonia Mountains, Arizona

      Moreira Coutinho, Paulo E.; Gordon, Grant J.; Gregorski, Alan C.; LaSala, Blase; Moore, Tim; Morse, Brittany A.; Moulton, Ethan; Sternberg, Ben K.; Zech, Stephanie N.; University of Arizona (LASI Laboratory for Advanced Surface Imaging, The University of Arizona (Tucson, AZ), 2018-06-16)
      In late 2015, after abnormally heavy monsoon rains in the Coronado National Forest south of Patagonia Arizona, an orange discharge was observed in the creek bed below the entrance to the abandoned Lead Queen Mine. This caused the U.S. Forest Service and United States Geological Survey (USGS) to mobilize to determine the cause and investigate actions to prevent future occurrences. Our studies included Transient Electromagnetics (NanoTEM), DC resistivity, EM-31 and Ground Penetrating Radar (GPR) surveys around the Lead Queen Mine for the United States Geological Survey. Data collected around Lead Queen Mine show a large highly conductive layer within the immediate area of the mine. Data from the NanoTEM and DC resistivity surveys show an anomaly with resistivities less than 6 ohm-m at depths varying from 20 to 60 meters. This anomaly is present in all TEM transects and the DC resistivity line. The DC resistivity line also shows a high-resistivity area near where the adit has been predicted to be. Further west, near another adit, a low-resistivity layer does not appear until beyond 60 meters depth. Data collected using the EM-31 shows no change in resistivity or conductivity along the stream-bed near Lead Queen Mine. GPR data did not effectively show a response to the adit, even with extensive manipulation using the RADAN software.