Caving performance through the integration of microseismic activity and numerical modeling at DOZ-PT Freeport,Indonesia

This article describes an undergoing research at PT Freeport, Indonesia, in which the main goal is to use the microseismic information recorded as a result of mining to analyze cave propagation and stress performance on the actual production and fixed infrastructure. At the moment, several numerical experiments have been conducted to correlate the mining activity with the microseismic events using the data collected during year 2005 and 2006. As a result of the preliminary analysis a micro- and a macrocracking envelop were proposed on the basis of computation of stress behavior at the location of the events. Stresses have been computed using standard elastic continuous boundary element models. The correlation between the average source radius and the stress performance has provided a method to propose a macrocracking criterion. Several techniques have been tested to nucleate the microseismic activity around different geological features. This last attempt was aimed to look at potential overstresses induced over the undercut and extraction level drifts. A method was devised to integrate the microseismicity into a 3-dimensional ride distribution model. This model has shown to be very effective to quantify the overstress induced as a result of computing volumetric microseismicity density. The volumetric microseismic model showed to induce overstress up to 10 MPa over a period of two months. The future work will concentrate on the calibration of the integrated model with actual damage observations made at the current mining infrastructure.