Incorporation of a Fault Factor into the Stability Graph Method: Kidd Mine Case Studies.

The stability graph method is a design tool used for open stope design in many mines throughout the world. After eighteen years of experience with this design tool, some limitations have been identified. One shortcoming of the stability graph method is the fact that it does not contain a factor that accounts for the presence of faults near the stope surface. This criticism is a legitimate one, considering that most metalliferous orebodies are associated with faults by their genesis, and that invariably, dilution in many open stopes is often related to the presence of faults. Therefore, a procedure that leads to the incorporation of a factor to account for faults in the stability graph has been developed to significantly improve the stability graph in predicting stope performance. Fault factor curves for use in the Canadian Shield where the in situ stress ratio K is often close to 2 have been proposed. This paper validates the use of the fault factor with case histories from the Kidd #3 Mine in Timmins, Ontario, Canada, and presents a stability graph that accounts for faults. The fault factor reduces the stability number N and improves the prediction of stope performance and improves dilution control. Two statistical indices are also presented for assessing the reliability of the stability graph in predicting open stope performance. [ABSTRACT FROM AUTHOR]