Rock Mechanics
Sina Alizadeh; Mohammad Reza Ghassemi; Mehran Arian; Ali Solgi; Zahra Maleki; Reza Mikaeil
Abstract
One of the most significant risks for investors in the dimension stone industry is the presence of natural discontinuities in the rock mass, which affect the quality of the extracted stone blocks. These discontinuities not only reduce extraction efficiency but also hinder the optimal utilization of the ...
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One of the most significant risks for investors in the dimension stone industry is the presence of natural discontinuities in the rock mass, which affect the quality of the extracted stone blocks. These discontinuities not only reduce extraction efficiency but also hinder the optimal utilization of the quarry. Therefore, it is essential to identify and analyze discontinuities in the rock before initiating any extraction activities and to assess the optimization of the extraction direction in dimension stone quarries. This study examines the key characteristics of discontinuities and joint sets, including their coordinates, strike, dip, spacing and aperture, in the Melika marble dimension stone quarry in Kerman. The collected data are then analyzed using 3DEC software to construct a quarry block model. Additionally, the azimuth rotation of different joint sets is investigated in four categories. The results obtained from the modeling indicate that, to achieve maximum blocking, the current extraction direction should be shifted 70° westward. This adjustment increases the number of blocks to 14,550, the average block volume to 5.5 m³, and the total volume of extracted stone to 79,918.9 m³. These changes are projected to generate approximately $3,180,000 in revenue for the quarry. The study highlights a practical optimization strategy that can significantly enhance the efficiency and profitability of dimension stone quarries by improving extraction direction based on discontinuity analysis.
Bijan Afrasiabian; Kaveh Ahangari; Ali Noorzad
Abstract
High-level vibrations caused by blasting operations in open-pit mining can exert adverse effects such as destruction of surrounding surface structures. Therefore, it is essential to identify the factors effective in mitigating the damaging effects of ground vibration in open-pit mines, and monitor them. ...
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High-level vibrations caused by blasting operations in open-pit mining can exert adverse effects such as destruction of surrounding surface structures. Therefore, it is essential to identify the factors effective in mitigating the damaging effects of ground vibration in open-pit mines, and monitor them. This study investigates the effects of some of the most important blast design parameters in a row of blast holes. According to the advantages of numerical methods, the 3D discrete element method is employed for this purpose. The Peak Particle Velocity (PPV) values are measured along the central hole at the distances of one meter. The results obtained demonstrate that an increase in the blast damage factor and inter-hole delay time results in higher PPV values. However, the increased delay time has no remarkable effect on reducing the development of the blast damage zone. On the other hand, as the decoupling increases, the PPV values diminish, leading to substantial reductions in the ground vibration and rock mass damage. It is also observed that the elimination of sub-drilling does not significantly reduce ground vibrations. The analysis of the results obtained from the numerical modeling show that the discontinuities of the rock mass act as a filter, which could decrease the wave energy by more than 90%. Moreover, it is found that the direction of the discontinuities also affects the emission of waves caused by the blast. The PPV values are reduced, and the damaged zone is less developed if the discontinuities are opposite of the slope surface.
