Assessing Sensitivity of Subsurface Mine-Dewatering Activities to Climate Change
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Date
2023-09-01
Authors
Calvert, Adam
Journal Title
Journal ISSN
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Publisher
University of Waterloo
Abstract
Underground mining activities require constant removal of groundwater from their void
spaces to maintain dry and safely accessible excavations for ore extraction in a process known
as dewatering. The nature and degree of dewatering activities is heavily dependent on the
amount of groundwater that can reach the mined areas and, conversely, dewatering of mines
has a significant effect on the regional groundwater flow in their vicinity. Furthermore,
groundwater supply to mining areas may be linked to climatic conditions, connected surface
water bodies and the geologic structures that link the surface and subsurface. Typically, fully
saturated groundwater models are used in industry to simulate site conditions and to plan mine
dewatering infrastructure. These models often take historical climate averages into account
when determining recharge to groundwater from the surface, and they do not typically account
for feedback between groundwater and surface water systems. While this has been sufficiently
accurate in the past, it is expected that the progression of climate change will yield future
estimates of groundwater recharge that differ significantly from historical averages. These
changes may be captured more accurately with fully coupled methods of simulating
groundwater and surface water simultaneously in areas with large surface water bodies
overlying aquifers, or in locations where geologic structures provide significant preferential
pathways between the surface and subsurface.
Here, we explored the changes in predicted dewatering rates for a real mining property
in Central Quebec when considering a typical, industry standard fully saturated groundwater
model with historically averaged recharge and a fully integrated groundwater/surface water
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model that incorporates results from future climate scenarios. The two models were
constructed, parameterized, and calibrated for a site in Central Quebec. Simulations of
underground mine dewatering were run with both models, and the predicted dewatering rates
from each model were compared. Simulation results demonstrated that the fully integrated
groundwater/surface water model with future climate yielded an estimated rate of dewatering
that was approximately 2% higher than that predicted by the fully saturated groundwater
model with historical climate averages.
Description
Keywords
hydrogeology, groundwater, numerical, modelling, climate