Mining Publication: Analysis and Design of Rib Support (ADRS): A Rib Support Design Methodology for Australian Collieries
This paper summarizes the results of a research project whose goal was to provide the Australian coal industry with a rib support design methodology and software tool that could be used by suitably qualified colliery staff. The project was funded mainly by the Australian Coal Association Research Program (ACARP) and further supported by several Australian longwall operations. The outcome of the project is a design methodology and software tool called Analysis and Design of Rib Support (ADRS). ADRS is an empirical technique; it recognizes that several geotechnical and design factors affect ribline performance and, in addition, that operational and safety issues essentially dictate the level of performance required. Therefore, the design recommendations associated with ADRS are specific to the Australian coal industry. However, the procedure(s) for data collection and analysis could be applied to the underground coal industries of other countries. Case history data were compiled from 34 longwall and 2 bord-and-pillar operations. This resulted in 204 case histories; each case history data set was defined by about 130 individual data fields. In addition, monitoring (incorporating stress cells and extensometers) was undertaken at 10 collieries to assess and quantify the effectiveness of different rib support patterns and hardware on rib performance. The monitoring sites allowed for an improved understanding of the mechanisms of rib failure and degradation in terms of interaction with the installed support and at various stages of the mining cycle. The design methodology deals with both mains development and gate road development specific to Australian longwall mines. This paper focuses on longwall gate roads subjected to abutment loading and, in particular, the travel road, which becomes the tailgate of the subsequent panel. The statistical analyses associated with these cases suggested that the level of rib support should be based mainly on the development height and the pillar stress level. The ADRS software guides users through the design process. It allows them to develop rib support plans based on sound science and a broad base of in-mine experience. To the best of our knowledge, ADRS is the first systematic rib support design technique to be developed for any country's underground coal industry. The development and use of empirical models in mining have substantially contributed to improving safety and productivity. ADRS further demonstrates that empirical techniques are particularly relevant and beneficial in dealing with the complexities of geotechnical design associated with underground coal mining.