Consolidation and hydraulic conductivity testing of slurries

A prototype apparatus was designed for large strain consolidation and hydraulic conductivity testing of slurried materials. The apparatus consists of three parts; loading frame, consolidometer pot and constant head flow system. The unique design of the loading frame allows for large strains. The frame can accommodate consolidometer of various diameters and heights. Stainless steel rings with diameter of 152mm and height of 163mm have been used. Each consolidometer pot has ports for a series of manometers along its entire operating height that allows for monitoring of pore-water pressures during consolidation testing or heads during hydraulic conductivity measurement. The constant head system allows consolidation testing to be conducted with preselected constant back-pressure. The back-pressure can be selected to match head to be used in hydraulic conductivity measurement on completion of consolidation. This prevents disturbances to the hydraulic regime of the test specimen when going from consolidation test to hydraulic conductivity measurement. [All papers were considered for technical and language appropriateness by the organizing committee.]Non UBCUnreviewedOthe

Potash tails pile field test covers

A field test program was established to examine potential potash tails cover materials and investigate the requirements of such covers. Potash tails consist of soluble salts and a small percentage of insolubles. Precipitation falling on these tails dissolves the salt, creating a saturated liquid brine. Most of the brine generated is contained in ponds around the base of the pile, and periodically injected into deep underground formations. The use of covers to minimize brine generation is one method currently being examined as a decommissioning option. A preliminary three year laboratory program and review of potash cover experience was used as the basis for designing the field cover program. Two full scale 20m X 20m test covers have been constructed on an abandoned potash tails pile. One of the covers was constructed from glacial till overlying a coarse boulder capillary barrier. 1'he second was constructed from polymerized bentonite and sand. These covers are currently being monitored to evaluate their performance.Non UBCUnreviewedOthe

Managing for closure at the Myra Falls Operation : the design of a soil cover system for long term ecological and physical stability

Westmin's Myra Falls Operations has the one single largest environmental problem facing the mining industry today. The tailings and waste rock materials are acid generating. A review of existing literature indicates that there are a number of technologies that can be used and developed for the prevention and control of acid generation in sulphidic mine tailings and waste rock. The majority of the ARD control technologies are centered around the curtailment of oxygen and water to the waste material. The most promising technology for Westmin's Myra Falls Operations is engineered soil covers. An initial cover design evaluation using local till materials indicated that the materials were not suitable for the proposed application. However, the soils were modified with a selection of amendments and the laboratory results showed significant improvements. The results suggest that local till materials amended with either flyash or bentonite can be used in soil cover construction. Westmin intends to conduct field trials to evaluate the performance of a short list of soil cover variations to determine the final cover system design as a result of the encouraging laboratory and soil-atmosphere modelling results. This paper summarizes the results of the laboratory characterization of the potential cover and waste materials and presents the soil-atmosphere numerical modelling used to design the field test plots. Construction aspects, instrumentation, vegetation, two-dimensional flow and in general the scope of the project will be briefly discussed. The successful use of local till material ameliorated with a fine grained material will provide a positive impact to the mining industry. This application to the design of soil cover systems is a novel approach which offers an economic alternative for decommissioning smaller waste rock piles and tailings management facilities.Non UBCUnreviewedOthe