Recommended guidelines for the stabilization of historic underground mine workings

The stabilization of historic underground mine workings has become an important construction, environmental, and safety issue. Underground workings such as shafts, open stopes, raises, inclines, and drifts present voids in the subsurface that may impact the stability of surface structures (homes, roads, rail lines, gas lines, etc.). Often the underground workings are not well documented so that the stability of the workings cannot be readily determined. In addition, underground workings may provide sinks for the collection of acid drainage and/or noxious/explosive gases. This paper presents recommended guidelines for the stabilization of historic underground workings. These guidelines have been developed based on lessons learned from the remediation and stabilization of over 400 mine workings in both hard and soft rock. The paper also discusses the practical aspects of remediation/stabilization and important design issues.