Geotechnical risk assessment of haulage drifts during the life of a mine plan

点击翻译按钮获取中文摘要

In a globally competitive minerals market, Canadian mines continue to face the pressure to reduce costs. One approach to reducing mining costs is by the reduction of unplanned interruptions to production for the rehabilitation of haulage drifts. These drifts are the principal roadways for haulage trucks and load-haul-dump vehicles, which transport the blasted ore from the mining block or stope to the nearest ore transfer facility such as an ore pass. Unplanned interruptions to production can have adverse influence on the cost of mining and ultimately on the profitability of an operation. Drift rehabilitation involves the installation of additional ground supports to help the drift regain its stability and functionality. Thus, it would be advantageous to be able to know ahead of time when and where a haulage drift is due for maintenance or support enhancement during its service life so that a preventive maintenance program can be scheduled and implemented in a timely fashion without interruption to production. Currently, there are no established guidelines to help the mine planner assess drift stability condition as it changes (deteriorates) with mining activities. The goal of this research project is thus to develop new design tools capable of predicting the location, timing and magnitude of required drift support enhancement with respect to scheduled mining activities during the service life of the drift. With these new tools, interruption to production schedule can be eliminated or minimized thus reducing cost. The new design tools will be developed from the study of the geotechnical risk of drift instability and how it is affected by the extraction of nearby mining blocks. Drift geotechnical stability is determined from numerical (computer) modelling analyses which account for the rock mass properties as well as the geometric configuration of the mining system and block extraction sequence. Model results are then compared with measurements and /or observations from the field to validate the models. The project case study is the Garson Mine of Vale Inco Limited. While the study is focused on the Garson Mine, its findings will be applicable to many other underground metal mines in Canada and other mining countries.