Mining Publication: Technique to Assess Hazards in Underground Stone Mines: the Roof Fall Risk Index (RFRI)
The potential for roof falls in underground mines remains a clear and present danger for mine workers. An investigation of ground conditions in nearly 50 percent of the nation's underground stone mines found that the state of roof stability is primarily determined in a limited and subjective manner. These large-opening mines, with roof heights typically 7 m (23 ft) or more, make physical observation difficult. Although some mines use monitoring techniques to gain additional information on roof stability, this practice is usually short term and localized to address ground conditions in a particular section or part of the mine. A roof-fall hazard-assessment technique was developed based on engineering judgment acquired from extensive underground stone mine experience and on examination of the related literature. This technique utilizes observational processes to determine roof fall likelihood. Case-study scenarios offer a realistic picture of model implementation. Providing the mine level decision-maker with an accurate assessment tool to ascertain the level of ground fall hazards is expected to reduce mine worker injuries and fatalities. Moreover, the presences of danger can be overcome with a clear picture of quantified ground conditions.