Investigating the Relationship between the Physical, Mechanical and Chemical Characteristics of Rock-Mass with the Fragmentation of Blasting Products in Chagharat Iron Ore Mine

Abstract

            Blasting is one of the most important and costly operations in the mining process. In fact, blasting is the beginning of the rock comminution process in the mine. Dimensions of the blasted product will play a significant role in the effciency of stone crushing and grinding. Therefore, in order to yield a product with desirable size, it is firstly necessary to obtain precise knowledge about the physical, mechanical and chemical conditions of mineral blocks. In the present study, physical, mechanical and chemical characteristics of 27 iron ore blocks of Chagharat mine were taken after blast operation. Then, by taking images of the surface of the blasted block, an image analysis of the dimensions of blasting product was carried out. In the next step, rock samples were taken from the surface of the blasted block to conduct geo-mechanical and chemical tests. After conducting the tests, the relationship between the physical, chemical and mechanical characteristics of the tested rocks with the dimensions of the blast products (D₈₀, D₅₀) were investigated. The characteristics examined in this study include uniaxial compressive strength, modulus of elasticity, Poisson's ratio, indirect tensile strength, cohesion, internal friction angle, percentage of silica, iron and iron oxide in the Blasted block. Finally, using univariate and multivariate linear regression statistical analysis, equations were formulated to estimate the dimensions of the product (D₈₀, D₅₀) resulting from the blasting using the physical, mechanical and chemical characteristics of the rock masses of the blasting product, with coefficients of determination (R2) 97.21% for D80 and 92.48% for D₅₀.