New formula to determine flyrock distance on sedimentary rocks with low strength

Abstract

Abstract There are many methods that discuss the prediction of flyrock distance in blasting operation, but none of them specifically discusses flyrock distance in sedimentary rock with low strength. The empirical method based on a statistical approach also has no specific research on it. This study aims to obtain a formula for predicting flyrock distance due to blasting on a sedimentary rock with low strength using ammonium nitrate fuel oil. A total of 196 samples were obtained from the blasting that has been operated. The variables included for building the new prediction model of flyrock distance are stemming, blast-hole height, powder factor, and average charge per blast hole. The analysis was carried out using a statistical approach with the concept of regression and correlation. Unlike the previous model that applied a dimensional approach, the new model set each of the predictor variables to have their respective regression coefficients in order to see how they play a role in predicting the flyrock distance. The results show that burden, stemming, blast-hole height, powder factor, and average charge per blast hole significantly affect the flyrock distance. The variance in flyrock distance can be explained uniquely 3.50% by burden, 10.74% by stemming, 2.55% by blast-hole height, 2.32% by powder factor, and 2.76% by average charge per blast hole. The new proposed model of flyrock distance is better than the previous model by looking at the mean absolute percentage error. To predict the flyrock distance of sedimentary rock with low strength, the new model can be used.