Numerical simulation study on pressure slag blasting of a large-scale open-pit uranium mine
In order to improve the blasting quality of a large open-pit uranium mine,the role of pressure slag blasting technology in controlling blasting displacement and pile shape,as well as improving rock fragmentation,was studied.Using the FEM-SPH coupling algorithm of LS-DYNA software,numerical models of open-pit steps with slag pressing thicknesses of 5 m,8 m,and 11 m were established based on the drilling diameter and step height adopted at the mine site.The borehole diameter was 177 mm and the step height was 7.5 m.Based on numerical calculation results,the internal damage and explosion morphology of each model were compared and analyzed.The damage analysis results indicate that the model with a slag thickness of 5 m has a lower degree of internal damage and lower energy utilization efficiency;The model with a slag thickness of 8 m has a significant degree of internal damage,and the surface on the steps is completely broken;The model with a slag thickness of 11 m has a large crushing area and a small crushing area,resulting in excessive release of explosive energy towards the top free surface.The analysis of the explosion pile morphology shows that the explosion pile with a slag thickness of 5 m has a lower uplift and a larger forward distance;The explosive pile with a slag thickness of 8 m has a higher uplift,a smaller forward throw distance,and a more uniform distribution of forward throw degree in the direction of the step height.The uplift height fluctuates less between the blast hole rows;The explosive pile with a slag thickness of 11 m has the highest uplift and the smallest forward distance,and the uplift is lower between the two rows of blast holes,and higher at the blast hole position.The uplift height of the front row of blast holes is greater than that of the rear row of blast holes.It can be seen that under the simulation conditions,the blasting effect is the best for a slag thickness of 8 m,both in terms of internal damage and the shape of the blasting pile.On site tests have shown that as the thickness of the slag increases,the distance of the front throw decreases,the surface roughness of the explosion pile intensifies,and the height of the explosion pile increases,which is consistent with the pattern revealed by numerical simulations.This research provides a technical basis for the selection of key parameters for slag blasting in large-scale open-pit uranium mines;The numerical simulation and analysis of the blasting pile shape in open-pit slag blasting fills a gap in the research field of slag blasting.
open air blastingnumerical simulationslag blastingthickness of pressed slag
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