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A <br /> Project Descriptions AddanBrown <br /> mom <br /> EIS FOR UNDERGROUND URANIUM MINE, NORTHERN SASKATCHEWAN <br /> AdrianBrown was retained to perform a detailed inflow,refill, and water quality evaluation for the <br /> Midwest Lake uranium mine, located in northern Saskatchewan. In this project the prediction of,control, <br /> of,and treatment of inflow of mine water was critical to the permitting,public review, and operational <br /> cost of the project. The Midwest Lake deposit is a very high grade vein deposit, in which the <br /> underground exploitation is required to be conducted in such a way that mine personnel are protected <br /> from the effects of the radiation and radon emissions generated from the ore,which are in part impacted <br /> by the inflow of water.The material in the vicinity of the mine is of low permeability,with the result that <br /> the possibility exists that a low-discharge,or possibly a zero-discharge mining method could be <br /> developed. <br /> AdrianBrown conducted a major surface-based and underground groundwater investigation, including <br /> regional pumping tests,monitoring of the effects of dewatering of the overlying lake(as a large stress <br /> test),installation of a network of monitoring/water level wells, drilling and testing of underground <br /> groundwater test holes,installation and monitoring of the response of underground piezometers to the <br /> advance of the exploration mine,and sampling and evaluation of water quality from the mine and from <br /> wells and piezometers. The information collected from these investigations was integrated with <br /> information collected about geology, topography,meteorology, surface water hydrology, and <br /> geochemistry. Using this entire package of information,a detailed three dimensional model of the mine <br /> area and its environs was constructed,and calibrated against the observed groundwater heads in the area, <br /> the lake levels,and the dynamic head changes created by the drainage of the overlying lake. <br /> Using the calibrated model, detailed evaluations were made of the likely mine inflows during operation, <br /> and groundwater flow after operation, under a range of scenarios, including conventional mining, <br /> grouting protection,in-situ mining,and ground freezing. Based on these methods,mine inflow, <br /> dewatering requirements, mine water treatment requirements,and mine impacts during and after <br /> operations were predicted.These predictions were used for the purpose of input to the EIS which was <br /> prepared for the relevant Canadian environmental authorities,and for evaluation by the public review <br /> process. The entire work associated with the groundwater study was reviewed in detail, and the results <br /> were accepted as being appropriate for the purposes of supporting the EIS.The project has been accepted <br /> in modified form for production(using a downhole slurry technology),based in part on the <br /> demonstration that there will be no long-term impacts to surface or groundwater resources. <br />