Quantifying Landscapes: Developing Design Guidelines for Landforms Using a Geomorphic Approach

摘要

Mine operators have a responsibility to reclaim disturbed landforms, including waste rock piles, sothat they do not adversely affect the surrounding environment. Traditional approaches to mineclosure have emphasized short-term geotechnical stability of landforms, but often the engineeredstructures require maintenance over the long term. Recently, mine operators have considered usinggeomorphic approaches to design closure landforms with the goal of reducing long-termmaintenance and liability. According to the geomorphic approach, landforms should be designedso that their drainage systems replicate those of surrounding 'natural' terrain, which has evolvedtowards a steady state with the environment.Golder has used a geomorphic approach to develop guidelines for closure landforms at MountPolley Mine, a gold and copper mine in central British Columbia, Canada. Historical air photoanalysis, fieldwork, and GIS analyses were conducted to characterize watersheds and hillslopes onminimally disturbed terrain in the vicinity of the mine. Drainages in the region typically exhibit adendritic pattern. Variability in the number and length of streams, bankfull width, and bankfulldepth between studied watersheds is related to their size. Hillslopes are typically convexo-concave,with the maximum length of slopes decreasing with increasing steepness. The sizes of cross-slopeundulations vary by slope steepness, with the deepest undulations typically occurring on slopes ofmoderate steepness, which are likely near the toe of the hillslope.