| A systematic analysis of the operational and design relationships of the shortwall mining method is presented. This is the first comprehensive analytical study for predicting the expected performance and determining the important variables and parameters for the shortwall mining method since its inception in Australia in early 1959.;The operational and design relationships developed for shortwall mining method provides analytical as well as numerical tools for better planning and operations. The analytical expressions for the level of recovery, rate of recovery, operating times of continuous miner and waiting times of shuttle cars are derived. The expressions derived for the rate of recovery of the shortwall mining method are for two cases: (a) the rate of recovery under ideal conditions and (b) the rate of recovery under equipment failure conditions. A discrete Markovian process formulation is utilized for determination of the expected delays caused by the failures of continuous miner, shuttle cars and scoop car.;The results of the numerical analysis indicate that (1) the shuttle car capacity or payload is the most important parameter for the rate of recovery of the shortwall mining method, (2) the rate of recovery of the shortwall mining can be improved considerably by using the method in thicker seams, (3) the shuttle car speeds and production rate of the continuous miner require special attention during operation of a shortwall, (4) the rate of recovery of the shortwall mining method increases up to a certain panel width and then gradually decreases, (5) two-step retreat is superior to one-step retreat when the relocation time of the ratio-feeder is more than 150 minutes, (6) the shortwall mining operation requires skillful workers and close supervision to keep the rate of recovery of the method at a maximum attainable level.;This study concludes that the important variables and parameters and their range should be identified for an efficient shortwall mining operation and, a considerable increase in the rate of recovery can easily be attained by judicious choice of the values of the variables and parameters. |
