Preliminary Time Lapse Ground Penetrating Radar (GPR) Analysis to Evaluate the Effectiveness of Grouting in the MSR MP 53 PT Freeport Indonesia

Abstract

This study presents a preliminary analysis using the time-lapse Ground Penetrating Radar (GPR) method to evaluate the effectiveness of grouting in the MSR MP53 area of PT Freeport Indonesia, the only access to the highlands that often experience slope failures. Grouting is used to fill cracks and rock voids to improve stability, and GPR was chosen as a fast, high-resolution non-destructive method. GPR sur- veys were conducted before grouting to identify areas requiring repair and after grouting to determine the success of the injection, with data processing steps such as inverse amplitude decay, background removal, bandpass filtering, predictive de- convolution, and migration. The comparison of GPR cross-sections showed signif- icant changes in reflection patterns, indicating the success of the injection at depths of 3–20 meters. These results align with the planned injection stages and confirm GPR as an efficient method for monitoring and verifying subsurface improvements in mining infrastructure.