Roadway design efficiency indices for hard coal mines

Abstract

Maintaining roadway stability is one of the crucial problems in the process of designing mining operations. There are many geotechnical systems and ratings describing the geological nature of rock mass, but only a few which take into account the mining and technical factors. The authors have therefore developed two practical indices for a quick and easy roadway stability assessment: Roadway Design Efficiency index (“RDE”); and Roadway Functionality Maintenance index (“RFM”). RDE can provide information regarding potential difficulties in ensuring roadway stability in advance of working drivage, based on geological, geomechanical and mining data. RFM evaluates the success of roadway maintenance in a given time range for the selected technical solutions. These indices can also help in choosing the design method for reinforcement of the underground support. Low values suggest the necessity of increasing support load bearing capacity. The rank of the geological, mining and technical factors is based on Analytic Hierarchy Process analysis and the data come from the survey carried out among mining engineers. The calculated RDE and RFM indices have been compared to the results of in situ measurements in the selected underground hard coal workings.