Energy characterization based assessment of pillar recovery

A number of pillars are left developed in some of the Chinese metal mines due to careless mining and lack of proper planning. There are pillars in such mines which do not contribute much in supporting the covered rock mass. Re-exploitation of these standing (non-supporting) pillars can be an efficient method for resource recovery if the remaining pillars ensure the stability of the covered host rock. In this study, a tungsten mine in Jiangxi Province, China, was chosen as a case for studying this pillar recovery scheme. Based on accurate in situ stress measurement data in the original and disturbed host rock, the storage energy in the rock mass could be estimated by numerical simulation methods. After comparing the storage energy to the sum of the fractured energy consumption and friction energy consumption (obtained from lab tests), the recyclable pillars can be identified by a cyclic judgment programming process.