TY - JOUR
T1 - Hydrogeology of the vicinity of Homestake mine, South Dakota, USA
AU - Murdoch, Larry C.
AU - Germanovich, Leonid N.
AU - Wang, Herb
AU - Onstott, T. C.
AU - Elsworth, Derek
AU - Stetler, Larry
AU - Boutt, David
N1 - Funding Information:
We appreciate the support from the National Science Foundation under grants EAR- 0809820, EAR 0900163, CMMI 0919497, EAR 1036985, EAR 0969053 and EAR 0919357.
PY - 2012/2
Y1 - 2012/2
N2 - The former Homestake mine in South Dakota (USA) cuts fractured metamorphic rock over a region several km2 in plan, and plunges to the SE to a depth of 2. 4 km. Numerical simulations of the development and dewatering of the mine workings are based on idealizing the mine-workings system as two overlapping continua, one representing the open drifts and the other representing the host rock with hydrologic properties that vary with effective stress. Equating macroscopic hydrologic properties with characteristics of deformable fractures allows the number of parameters to be reduced, and it provides a physically based justification for changes in properties with depth. The simulations explain important observations, including the co-existence of shallow and deep flow systems, the total dewatering flow rate, the spatial distribution of in-flow, and the magnitude of porosity in the mine workings. The analysis indicates that a deep flow system induced by ~125 years of mining is contained within a surface-truncated ellipsoid roughly 8 km by 4 km in plan view and 5. 5 km deep with its long-axis aligned to the strike of the workings. Groundwater flow into the southern side of the workings is characterized by short travel times from the ground surface, whereas flow into the northern side and at depth consists of old water removed from storage.
AB - The former Homestake mine in South Dakota (USA) cuts fractured metamorphic rock over a region several km2 in plan, and plunges to the SE to a depth of 2. 4 km. Numerical simulations of the development and dewatering of the mine workings are based on idealizing the mine-workings system as two overlapping continua, one representing the open drifts and the other representing the host rock with hydrologic properties that vary with effective stress. Equating macroscopic hydrologic properties with characteristics of deformable fractures allows the number of parameters to be reduced, and it provides a physically based justification for changes in properties with depth. The simulations explain important observations, including the co-existence of shallow and deep flow systems, the total dewatering flow rate, the spatial distribution of in-flow, and the magnitude of porosity in the mine workings. The analysis indicates that a deep flow system induced by ~125 years of mining is contained within a surface-truncated ellipsoid roughly 8 km by 4 km in plan view and 5. 5 km deep with its long-axis aligned to the strike of the workings. Groundwater flow into the southern side of the workings is characterized by short travel times from the ground surface, whereas flow into the northern side and at depth consists of old water removed from storage.
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U2 - 10.1007/s10040-011-0773-7
DO - 10.1007/s10040-011-0773-7
M3 - Article
AN - SCOPUS:84922686276
SN - 1431-2174
VL - 20
SP - 27
EP - 43
JO - Hydrogeology Journal
JF - Hydrogeology Journal
IS - 1
ER -