Calibration of the analysis of longwall pillar stability(ALPS) chain pillar design methodology for Australian conditions

摘要

This paper summarizes the results of a researchproject whose goal was to provide the Australian coal industrywith a chain pillar design methodology readily usable by collierystaff. The project was primarily funded by the Australian CoalAssociation Research Program and further supported by severalAustralian lingwall operations.The starting point or basis of the project was the Analysis ofLongwall pillar stability (ALPS) methodology. ALPS was chosenbecause of its operational focus; it uses tailgate performance as thedetermining chain pillar stability. Furthermore, ALPS recognizesthat several geotechnical and design factors, including (but notlimited) chain pillar stability, affect that performance.There are some geotechnical and mine layout differencesbetween United States and Australian coalfields that requiredinvestigation and, therefore, calibration before the full benefitsoffered by the ALPS methodology could be realized in Australia.Ultimately, case history data were collected from 19 longwallmines representing approximately 60% of all Australian longwalloperations. In addition, six monitoring sites incorporated an arrayof hydraulic stress cells to measure the change in vertical stressthroughout the various phases of the longwall extraction cycle.The sites also incorporated extensometers to monitor roof and ribperformance on response to the retreating longwall face.The study found strong relationships between the tailgatestability facto, the Coal Mine Roof Rating, and the installed levelof primary support. The final outcome of the project is a chainpillar design methodology called analysis of longwall tailgateserviceability (ALTS). Guidelines for using ALTS are provided.