Primary Blasting Optimization under Sub Level Caving: Application to the Kipushi Underground Mine, DR Congo

Mining in which any extraction occurs below the surface of the Earth is called underground mining. It consists of mining the ore from an excavation created below the surface of the ground, underground, without having to remove the entirety of the sterile materials which surmount it. The choice of an underground mining method is often closely related to the geology of the deposit and the degree of soil support required to make the methods productive and safe. The Kipushi underground mine is exploited by the Sublevel caving method which is a vertical extraction method in which a large open construction site is created in the vein. It turns out that its implementation requires a considerable amount of preparatory work and generally in waste rock. Now in these days, most studies converge towards the noticeable diminution of work with the rocks. To remedy this, we proceed for our study by an approach of empirical formulas. We started with an evaluation of mining ratios in Sublevelcaving by making a calculation of the explosives and fireworks by a theoretical determination of the load and by a presentation and analysis of diagrams in tracing and unstacking. Then followed by an analytical study of the techniques of caving by dimensioning the works of the mines, the determination of the exploitation height, in order to seek a rational solution for the primary mining in sublevel caving which is among the preoccupations of the underground mine from Kipushi. The analyzes and technical solutions envisaged to rationalize the operations of the primary mining in sublevel caving, prove that one will invest less for a sub-level of 17, 50 m instead of two sub-levels of low height of 12.50 m. The advantage of increasing the height of the sub-levels results in a gain in dry ton ore per unit of time and a decrease in the cost of implantation of the sub level. After optimum study of existing fire patterns, and ultimately, the result confirmed that that of 11 holes for the sub-level of 12.5m and 16 holes for the sub-level of 17.5 m are rational schemes. This will not prevent the operator from choosing one or the other in the choice of the operating sub-level (12.5 m or 17.5 m).