| To access the orebody, in a mining operation, it is generally necessary to extract waste rock which is material that does not have an economical value. These rocks are usually stored on surface in piles, or, in underground operations, in stopes that have been excavated. The waste piles on surface can be very large, with a height greater than 100 meters and an area of many hectares. The oxidation of waste rock containing sulphur rich minerals may cause acid mine drainage (AMD). Waste rock piles usually have properties that favour the development of AMD, such as: high material heterogeneity, segregation in the pile caused by the waste rock dumping method, presence of preferential flow paths and low saturation level of the material in the pile. All these characteristics favour the flow of fluids (water and air). To minimize AMD production, it is therefore important to have a good grasp of the components influencing flow of water in the waste rock piles.;This project consists in studying the hydrogeotechnical properties of mine waste rocks. The main objective is to evaluate the factors that influence flow of water in these materials, to be able to improve the characterisation methods in the field, in the lab and with numerical models. To do so, field work (infiltration tests, in situ density measurements and sampling) was completed on the waste rock pile of the Goldstrike property owned and operated by Barrick Gold Corporation Inc. On the site, it was possible to observe the heterogeneity of the materials in the piles. The field work also helped better understand the effect of surface layers compacted by heavy machinery (e.g. haul trucks) on the pile hydrogeology. (Abstract shortened by UMI.). |
