Development of a Multiplication Factor for the Kuz-Ram Model to Match the Fragment Size Obtained from Wipfrag Image Analysis

Abstract

The degree to which the rock is fragmented by blasting operations significantly impacts the productivity of the opencast mining operation. Over image analysis-based tools, the Kuz-Ram empirical model is preferred for determining the mean fragment size of a blasted muck pile. The fragmentation analysis results by the Kuz-Ram model are said to report the overestimation of the size of the fragments. On the other hand, while accurate, measuring the mean fragment size by image-based analysis is also time-consuming and expensive. Therefore, in the present research, the fragmentation difference index (Fdi) is introduced as a new multiplication factor to reduce the discrepancy in the results obtained using the Kuz-Ram model and the image-based analysis. The error minimization method of least squares is used to formulate the objective function of Fdi. The proposed equation is tested using data sets that weren't used in the model's development. Statistical indicators viz. the coefficient of determination (R2 ) and Root Mean Square Error (RMSE) have been used to evaluate the model's performance. These are found to be 0.80 and 0.007, respectively. The values obtained by multiplying Fdi by the Kuz-Ram results match those of the Wipfrag study, with an average error of 2.09%. Therefore, the suggested methodology will assist the field engineers in cost-effectively calculating the mean fragment size before blasting utilizing only the findings from the Fdi and Kuz-Ram models.