The Application of ‘Paste Rock’ for Cover Systems in Mine Waste Management

Authors: Wilson, GW; Miskolczi, J; Dagenais, AM; Smith, Q; Lanteigne, L; Hulett, L; Landriault, D Paper is not available for download Contact Us

DOI https://doi.org/10.36487/ACG_repo/663_18

Cite As:
Wilson, GW, Miskolczi, J, Dagenais, AM, Smith, Q, Lanteigne, L, Hulett, L & Landriault, D 2006, 'The Application of ‘Paste Rock’ for Cover Systems in Mine Waste Management', in R Jewell, S Lawson & P Newman (eds), Paste 2006: Proceedings of the Ninth International Seminar on Paste and Thickened Tailings, Australian Centre for Geomechanics, Perth, pp. 209-219, https://doi.org/10.36487/ACG_repo/663_18



Abstract:
Conventional mine waste management systems produce a wet tailings stream and a dry waste rock stream. Tailings and waste rock have strikingly different properties with respect to texture and soil behavior. Fine grain tailings tend to feature a low permeability but are commonly discharged at high water content with low shear strength and have slow consolidation properties with high volume change characteristics. Alternatively, the dry waste rock stream is typically coarse rock, cobble and gravel that offers high physical stability; but also permits high water infiltration and oxygen entry for sulphide oxidation and acid generation. In general, neither material is suitable for cover construction and long term reclamation. Cover systems constructed on potentially acid forming tailings impoundments or waste rock dumps must function as oxygen and water barriers in order to minimize acid rock drainage. The barrier system within a cover profile must also provide physical stability with respect to deformation, shear strength and erosion. Long-term integrity of cover systems is a critical issue due to extreme variations in climatic and environmental conditions associated with temperature, freezing, wetting and drying, and vegetation. These variations may cause volume change and cracking leading to failure associated with excessive infiltration and/or oxygen entry. In general, well-graded soils with a fine grain matrix such as the glacial till material used at Equity Silver Mine in British Columbia have been proven to be excellent materials for the construction of barrier type cover systems. INCO has initiated a field and laboratory study to investigate the potential of blending tailings, waste rock and slag (a mixture the authors have termed ‘paste rock’) at the Copper Cliff Mine in Sudbury, Canada to produce a suitable material for the construction of a barrier cover system. A preliminary laboratory test program was conducted that indicated it should be possible to produce a high quality cover material. The decision was subsequently made to proceed with the construction of field scale lysimeters to measure the performance of cover systems constructed using blended waste rock, tailings and slag as paste rock material. The design, construction and predicted performance of the lysimeters are described herein. Paste2006–R.J.Jewell,S.Lawson,P.Newman(eds) ©2006AustralianCentreforGeomechanics,Perth,ISBN0-9756756-5-6 Paste2006,Limerick,Ireland 209

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