76 / 2021-09-17 15:47:38

Blasts aimed at roof protection in development of structures in Lubin mine – case study

drilling and blasting,smooth blasting

Underground operations in mines require preparation of many different types of specific structures which are necessary for exploitation purpose and has to maintain its defined function during the long period. It concerns important transportation and ventilation drifts, warehouses, workshops etc.  These kinds of facilities may have various shapes and dimensions from very small, with several cubic meters volume to the very large with thousands of cubic meters. In the case of some chambers, areas of cross-sections may reach more than 100 square meters and length dozens of meters. The vital importance of this kind of facilities for safe and efficient mining operations requires special attention during their building, securing and maintenance. In KGHM mines, including Lubin mine, these kinds of structures are prepared by means of blasting works which may have negative impact on the stability of roof layers. Therefore blasting works, which are employed during construction of these structures should be designed to limit destructive effect of blasting on the roof. These kinds of facilities may be very interesting in the light of potential places for the future location of underground laboratories after the closure of mine or even during mining operations when given place become useless for overal technology process. In the present research the changes in drilling and blasting patterns in terms of proper protection of roof layers were prepared for the conditions of Lubin mine and presented. There were conducted several tests to verify the proposed approach in real mining conditions. Utilized technology applies standard explosives that are normally employed in blasting works. Modifications are focused on changes in drilling pattern, limitation of the amount of explosives in specified holes and timing. The presented changes can also be applied in other mines with similar geotechnical conditions.