Transportation costs: A tool for evaluating the effect of rock mass mechanical parameters on blasting results in open pit mining

Abstract

Blasting is one of the most important stages of open pit mines extraction which plays an essential role in changing the extraction costs. Mechanical parameters of rock mass as fixed parameters are results of effective blasting. In this paper, the costs of transportation have been introduced as a tool for determining the blasting quality and transportation operation in open pit mine of Angouran (the largest lead and zinc mine in the Middle East) has been discussed. Approximately, 55 percent of the piles from blasting conducted in Angouran mine are appropriate for loading by hydraulic shovel and the rest of the piles are not appropriate for loading by most machines. This has led to a significant change in transportation costs caused by blasting quality. First, the mechanical parameters of the rock mass (compression strength of intact rock, RQD, discontinuity conditions, the angle between the joints and direction of drilling and slope discontinuities) as well as all transportation costs (total cost of loading, hauling, and bulldozers work) in the 104 blocks of extractive mining of Angouran were surveyed. Regarding blasting pattern which is constant approximately in studied blocks, an equation was proposed to determine the relation of geotechnical parameters associated with the transportation costs. Ultimately by conducting a sensitivity analysis it was determined that uniaxial compressive strength of rock and difference of bench face dip and joint dip have the greatest impact on the quality of fragmentation and thus changes in the cost of transportation in Angouran mine