Estimation of the effectiveness of the destruction of natural stone oversized by a hydraulic hammer

Abstract

The experience of mining operations shows that even with the application of progressive methods of drilling, it is impossible to completely exclude the output of a large fraction (oversized). The percentage of oversized mass emissions from the blasting mass depending on the mining and geological conditions may vary from 5 to 20 percent. Catching an oversized piece into the receiving slit of the main crusher is associated with stopping the whole technological chain of the enterprise. Sharpening of oversized pieces of the work area during conducting of extraction or overturning works leads to a decrease in the efficiency of mining operations. Crushing of oversized materials to the required sizes can be carried out in an explosive way (by a bore or overhead charge) or by non-explosive methods, most of which are based on mechanical destruction under the action of local dynamic stresses that cause stress exceeding the resistance of internal bonds in the rock. To date, manufacturers are offered many types of shock mechanisms, based on the transformation of various types of energy (from gravitational, to the energy of chemical processes) into mechanical. For a number of reasons, mostly economic, to date, the most common way is the mechanical method of the destruction of oversized beams using hydraulic and hydro pneumatic hammer. That is why the work considers the main factors influencing the performance of the hydraulic hammer, among which – the specific energy consumption of the oversize and the main parameters of the hydraulic engine passport on the basis of the excavator. In the publication the power law of the hydraulic hammer changes in dependence of the size of the oversized. Also, the basic parameters of the JCB JS235 HD excavator passport are defined in the work with the use of the INDECO HP 1500 hammer hammer.