Simulação da fragmentação dos desmontes de rochas por explosivos

Abstract

This doctoral thesis presents a literature review of fundamentals in blasting fragmentation simulation. Based on this review, a simulation model was developed, using the models: Kuz-Ram and the TCM (Two Components Model). This model originated a computer program named SIMBLAST, developed in a partnership with CVRD (Companhia Vale do Rio Doce). The data to test this program were obtained at Carajás iron and copper mines, located in the south of Pará state. The simulator wastested in hard hematite blasting, aiming at the reduction of fines generation. At the copper mine, the simulation was used to determine the blast design parameters, adequating the fragmentation to the primary crushing requirements. The blasted particles sizes were measured by photo analysis. To have a higher reliability in the simulation input data, the following tasks were performed at the mine and labs: measuring the explosives VOD, uniaxial compression strength tests, calculation ofdrilling specific energy and rock mass classification. The analysis of the results showed that for hard hematite blasting, the 12 ¼ diameter blasthole, currently used, must be reduced to 6 ½ diameter, and ANFO explosive must be used instead of the heavy ANFO. These changes in the blast design reduce fines generation in hard hematite blasting. With the objective of validating the simulation program, a test was performedwith granite blasting at Sossego copper mine. For this blasting, the simulated curve was compared with the curve obtained by photo analysis. The results showed a good adherence between both curves.