In late September, 2014, unusually heavy monsoonal rains were followed by citizen observations of bright orange "sludge" flowing in streams in the vicinity of the Lead Queen and Trench Camp Mines in the Patagonia Mountains. Lead Queen is an abandoned mine located on U.S. Forest Service land, and Trench Camp is a mine site that was remediated in the 1970s and is currently managed by Asarco Multistate Environmental Custodial Trust. At Lead Queen, flushing of adits and shafts by rapid inflow of rainwater apparently led to the mobilization of iron- and aluminum-rich sludge, which has mostly settled in the upper canyons near the mine site. Similar flow occurred at the Trench Camp site due to the failure of a sediment dam and overflow of the wetlands area established as part of the remediation.
Critical issues include how these other contaminants have dispersed through the watershed, the extent to which they have been deposited in sediments that can be remobilized in future events, the potential for future contaminant outflows from these two sites as well as other sites in the selected southeast Arizona mountain regions, and developing a plan for future USGS response to this and similar events in other areas. With the USGS's experience with rapid response, unbiased science, and the nationally and internationally recognized quality of its data and protocols, the USGS is in a unique position in the current situation to aid with and conduct sampling, monitoring, and modeling to provide a comprehensive perspective on the ongoing environmental hazards posed by the legacy of mining in the Patagonia Mountains and, in general, predict surface and groundwater potential vulnerably in new start-up areas.
This pilot project will undertake efforts to:
Norman, L.M., Brinkerhoff, F., Gwillliam, E., Guertin, D.P., Callegary, J., Goodrich, D.C., Nagler, P.L., and Gray, F., 2016, Hydrologic Response of Streams Restored with Check Dams in the Chiricahua Mountains, Arizona: River Research and Applications, 32(4), p. 519-527, doi:10.1002/rra.2895.
Callegary, J., Gray, F., Norman, L., Bultman, M., and Heilman, J., 2016, Hydrologic Functioning of a Fractured-Rock Aquifer Containing Extensive Mining Tunnels and Open Drill Holes: 2016 National Groundwater Association (NGWA) Conference on Fractured Rock and Groundwater, Burlington, VT.
Callegary, J., Gray, F., Norman, L., Bultman, M., and Heilman, J., 2015, Hydrology and Water-budget Components of an Extensively Mined Area Using Geophysics, Geochemistry, Rainfall-runoff- and Sediment Transport Modeling: 2015 National Groundwater Association (NGWA) Conference on Groundwater in Fractured Rock, September 28-29, 2015, Burlington, VT.
Callegary, J., Norman, L.M., Eastoe, C., Wilson, N., Fandel, C., Gray, F., and Wiele, S., 2017, Multidisciplinary Modeling and Monitoring to Study Hydrologic, Geomorphologic, and Biogeochemical Effects of Restoration: 7th World Conference on Ecological Restoration, August 27-September 1, 2017, Iguazu, Brazil.
Gray, F., Page, W.R., Bultlman, M., and Menges, C.M., 2014, Hydrogeologic characteristics of the Miocene Nogales Formation: Potential new deeper source of groundwater in the upper Santa Cruze basin, southern Arizona: Geological Society of America Abstracts with Programs, Vol. 46, No. 6, p. 118. View Gray 2014 GSA abstract.
Geology, Minerals, Energy and Geophysics Science Center