Numerical Simulation Study on Dust Suppression Mechanism of Burning Rock Blasting in Open-Pit Mine

Abstract

In an open-pit mine in Xinjiang, part of the stripped area is covered by burnt rock. Due to the low strength and fragility of burnt rock, dust is more easily generated during blasting. Taking the mining area as the research background, the mechanical property parameters of burnt rock were tested, and the blasting parameter design of on-site operation was understood. The blasting numerical simulation of burnt rock step was carried out by using a numerical simulation software (LS-DYNA). From the angle of stress on rock, the stress cloud and stress curve of numerical simulation are analyzed, and it is concluded that the fundamental reason for the large dust production in blasting operation is that the burnt rock is crushed excessively after the action of explosion wave, and the explosive energy is too large, which is converted into kinetic energy to drive the dust to escape. In order to improve the utilization rate of explosives and reduce the output of blasting dust, the original blasting parameters were optimized as 8-m hole spacing, 6.5-m row spacing, 0.21-kg/m³ unit explosive consumption, 1-m interval charge, and 55-ms short-delay blasting through numerical simulation and orthogonal experiment. In the mining area, the measures of dustproof and dust reduction by blasting protection blanket and dust absorption cotton are adopted. Combined with the optimized blasting parameters, the field test proves that the dust removal efficiency is up to 82.4%.

Research on blasting mechanism and blasting effect of aqueous media in open pit coal mines

“…Jia, Z.Z. et al [10] used (LS-DYNA) to perform blasting of a coke rock bench Numerical simulations, from rock stress perspective, stress clouds and stress curves from numerical simulations, concluded that the root cause of the high dust production from blasting operations was the excessive fragmentation of the coke rocks after the blast wave, and the excessive blast energy was converted into kinetic energy to drive the dust to escape. Song, Y. q. et al [11,12] conducted dynamic compression tests on lignite with different impact rates, and the results showed that the increase in strain rate had a significant hardening effect on the dynamic mechanical parameters of the rock samples, and the stress-strain curve had an obvious "double-peak" feature; meanwhile, macroscopic cracks in the rock appeared at the first stress peak and disappeared after further compression until interlaminar fracture occurred.…”

Research on blasting mechanism and blasting effect of aqueous media in open pit coal mines

“…Cui 9 , a new method using water-silt composite blasting is presented, which improves the rock fragmentation rate, reduces rock buildup, lowers dust, and saves explosives. Jia et al 10 carried out numerical simulation of blasting on coke rock steps using (LS-DYNA) and concluded that the root cause of the high dust production from blasting operations is the excessive fragmentation of coke rock after the blast wave action. Song, et al 11 , 12 conducted dynamic compression tests on lignite with different impact velocities, and the results showed that the increase of strain rate had a significant hardening effect on the dynamic mechanical parameters of the rock samples.…”

A Multifactor Quantitative Assessment Model for Safe Mining after Roof Drainage in the Liangshuijing Coal Mine

“…The mechanisms for roof water inrush are different case to case. 3 , 6 − 8 One main mechanism for the water inrush is the roof failure after coal seam mining, which is thoroughly explored by scholars. 9 − 14 The major research method is conducting a similar model test.…”

“…Many types of roof water disasters are recognized in Jurassic coalfields, such as separated strata water disasters, water inrush, and sand inrush, roof thick sandstone water disasters, burning rock water disasters, etc. The mechanisms for roof water inrush are different case to case. ,− One main mechanism for the water inrush is the roof failure after coal seam mining, which is thoroughly explored by scholars. − The major research method is conducting a similar model test. However, the experimental conditions are way different from the actual conditions in the mine, which makes the results less convincing. − What is more, the geological conditions, hydrogeological conditions, lithology, and mining conditions are different from one mining area to another mining area, the research results cannot be widely applied, and the existing conclusions are not suitable for the Liangshuijing coal mine.…”