A stability-economic model for an open stope to prevent dilution using the ore-skin design

In this study, the ore-skin design approach is presented in the context of a hypothetical open stope mine. A stability-economic model was developed to estimate the ore-skin thickness that can be left unmined to maintain the integrity of an open stope and control excessive ore dilition from hangingwall sloughage. The first stage of the approach consists of performing a cost-profit analysis to determine an economic break-even ore-skin thickness. The second stage includes using discrete element numerical methods to evaluate the stability of a certain ore-skin thickness. Two numerical methods were employed for this assessment, including a discrete fracture network (DFN) method and a hybrid discrete element / discrete fracture network model. Results indicated that the minimum ore-skin thickness required depends on the quality of governed rock mass and can be a function of stope lifetime.