Feasibility of developing the Millstream potash deposit, Kings County, N.B.

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University of New Brunswick


There are three significant potash deposits in Kings County, New Brunswick which are shallow-marine deposits found in the Carboniferous Moncton Subbasin of the Maritimes Basin. Two of these deposits, located at Penobsquis and Cassidy Lake, were exploited starting in the mid 1980's. By 1997, both had experienced severe groundwater inflow problems into their mine workings. This resulted in the closure of the Potacan mine at Cassidy Lake in late 1997. The third deposit is the Millstream potash deposit, which is located 4 km west of Apohaqui. It was studied by British Petroleum Resources Canada Inc. in the early 1980's for its potential as a commercial potash development, but as of today it remains unexploited. The feasibility of developing the Millstream potash deposit, with particular attention being paid to the potential for groundwater inflow, was studied. The potential for severe groundwater inflow at the Millstream potash deposit was evaluated using the information available from British Petroleum. This included; downhole geophysical logging, daily drilling reports, seismic surveys, geological sections and hydregeological assessments. Geotechnical concerns with the presences of carnallitite and brine and gas cavities were also investigated. Personnel from the mining industry and the New Brunswick Department of Natural Resources and Energy Minerals and Energy Division were interviewed for their personal insight into the potential groundwater problems in the Millstream deposit and with other concerns regarding the development of the deposit. Recommendations for further exploration into the potential for groundwater inflow and several remediation measures are discussed. The potential for the deposit to be exploited as a solution mine is also explored. Of particular interest is the potential of exploiting the deposit for magnesium.