No description available.

This study reports the results of an investigation of the potential pollution hazard of a potash brine disposal pond located near Esterhazy, Saskatchewan. The most serious problems associated with the brine pond are the potential pollution of groundwater resources and the possible contamination of a nearby stream by groundwater discharge. The primary geologic feature is a glacial buried valley aquifer consisting of highly-permeable sands and gravels. A three dimensional electric analog model was constructed to simulate the steady state and transient groundwater flow systems in the buried valley aquifer. The steady state analysis enabled the author to calculate the convective travel times of the brine from the brine pond to the nearby creek. The transient analysis was used to assess the feasibility of reversing the hydraulic gradient in the buried valley aquifer. Steady state results indicate that the most serious potential pollution hazard is brine seepage onto the surface immediately east of the brine pond. At a distance of 5600 feet from the brine pond, this seepage will occur within 30 years; nearer to the brine pond, it will occur sooner. This type of brine seepage could enter the nearby stream as a result of surface drainage. Brine pollution by groundwater discharge directly into the creek will take between 640 to 1260 years, so this mechanism does not pose an immediate pollution hazard. Transient results indicate that low-rate injection wells (up to 50 IGPM) would not reverse the hydraulic gradient in the buried valley aquifer. Injection rates between 370 to 575 IGPM would be required, but fresh water supplies of this magnitude are not available. The design of future brine ponds should include seepage calculations in the initial phases of design instead of after the fact. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

No description available.

Increasing energy costs and the need to conserve energy compounded with low mineral prices have prompted some Canadian mines especially potash producers, to examine their operations and identify potential saving methods. Re-using or recirculating a fraction of ventilating air may enable these mines to reduce winter heating costs. Gas and dust concentrations were monitored in the intake and exhaust airways to assess the potential for recirculating exhaust air. The results indicate that the mine pollutant concentrations in potash mines are low and stable. Trial recirculation experiments returning 20 - 47% exhaust air into the fresh air airway did not cause significant increases in mixed intake pollutant levels. Two types of recirculation systems - namely variable and fixed quantity - are developed. Detailed designs of recirculation systems for Central Canada Potash of Noranda Minerals Inc. and Rocanville Division, Potash Corporation of Saskatchewan are discussed and recommendations made for the selection and positioning of on-line monitoring, control and telemetry systems. A controlled recirculation system conceptual design for the H-W mine is given. The economic payback periods for systems proposed for Rocanville Division and CCP are 2 and 3 years respectively. Recirculation percentages of 30%, 64.4% and 23% are feasible for CCP, Rocanville Division and the H-W mine. The recirculation percentages for the proposed systems were determined using Air Quality Index criteria. Dust deposition studies conducted at CCP in return airways indicate that 65% of dust by weight is deposited within a distance of 550 metres from the face. In terms of dust and other contaminant conditions in the return airways, it can be concluded that there is potential for use of recirculation in the face area. Guidelines for recirculation systems in gassy and dusty mines are developed. The main features for these recirculation system design guidelines are safety, economic gain, and system performance. The author's attribution to ventilation is in the use of controlled recirculation to reduce winter heating costs and increase underground airflow, also the guidelines developed for recirculation in gassy and dusty mines. The overall conclusion is that controlled recirculation is a practical method of reducing winter heating cost and/or increasing mine airflows. The financial potential and technology to implement a working system exist. / Applied Science, Faculty of / Mining Engineering, Keevil Institute of / Graduate