Rock Mechanics Investigations at the Lucky Friday Mine. Part 1. Instrumentationof an Experimental Underhand Longwall Stope

摘要

Researchers at the U.S. Bureau of Mines monitored rock mass response to mining ofan experimental underhand longwall stope in Hecla Mining Co.'s Lucky Friday Mine, Mullan, ID. The stope design, the Lucky Friday underhand longwall (LFUL), was proposed as a means of controlling rock bursting while, at the same time, allowing increased mechanization of mining operations. Instruments were specifically manufactured to monitor three geomechanical factors (backfill performance, ramp stability, and rock mass response) that directly affect the success of the stope design. Despite considerable difficulties with instrument installation and survival in the harsh mine environment, especially within the stope fill, sufficient information was collected to suggest that the LFUL method was successful in achieving project goals. The conclusion, along with favorable economic and operational evidence, led the mine to adopt the method throughout the mine.