Having increasingly tightened geological and mining conditions in which the extraction of copper ore deposits in Poland is conducted, ensuring effective and safe mining is presently becoming a key task and a significant challenge for mine operators, mainly in the field of ground support systems being the equivalent for the new geological/mining conditions. As one may expect, these conditions shall be characterized by higher values of the primary stress tensor elements as well as the lower deformability and higher strength of the rock mass surrounding the copper ore body. T his means that in the near future, the rock bursts problem will become one of the most important issues deciding on the economy and safety within the newly developed mining areas. T herefore developing a novel effective ductile ground support systems which could be able to control the rock mass movement in squeezing and burst-prone rock conditions is recommended. T his type of requirement may fulfil only ductile or, in other words, the kinetic energy-absorbing systems, which permit slowing down a movement of violently ejected rock blocks. T his paper’s objective is to present the idea of the development of a new type of an effective and low cost ductile resin anchored rockbolt system with smooth and of the square cross-section steel rod is formed in coil shape of different pitch. T he developed bolt prototypes have been tested underground in the G-11 section of the Rudna mine. Results of the pull-out tests, involving different bolts’ shapes and different sliding materials set on the rockbolts’ rods, have proved those bolts’ efficiency as an element of the ductile support system.
Caving in the excavation of mining galleries is a dangerous phenomenon, resulting in a threat to the health and life of humans, technological difficulties (transport, ventilation, etc.) and economic losses. Mining galleries list: design errors, runtime errors, errors and random causes among the causes of the caving occurring in recent periods in the excavation of underground coal mines. Examples in the recent period of caving in the excavation of mining galleries in coal mines indicated that one of the main causes of the situation was the loss of capacity and double timber technical wear caused by the corrosion of the profile. In practice, the caving that occur as a result of the technical wear can be divided into the breaking arc of a roof – bar, the loss of stability of one of the heading walls and a total heading collapse. On the basis of the carried out analysis of these cases, guidelines were proposed for improving the safe operation of the workings. The improvement of support stability may be achieved by applying additional supports, stabilizing the structure by bolting the support sets or by introducing a fiber-reinforced concrete coating with injection into the rock mass. Examples of caving occurring in the excavation, for which the preparatory selection of support does not match the geological-mining conditions, were also presented. The summary indicated the importance of diagnostics roadway in the safe and efficient conduct of mining that should be covered by the operational rules, and their scope and frequency should be adapted to the rank of the occurrence of hazard and support construction.