The main energy source in Poland is still hard coal and lignite. The coal combustion process produces large quantities of by-products, e.g. fly ashes, slag furnace and harmful chemical gases (CO2, NOx, sulfur compounds) which enter the atmosphere. Fly ashes, due to their being fine grained (cement-like), chemical and phase compound and reactivity, have also been widely used in various technological solutions e.g. in the production of ordinary cement, hydro-technical cement and the new generation of cements. The adequate amount of fly ashes additive has a positive effect on fresh and hardened cement slurry properties. What is more, it allows for the pro-ecological and economic production of cement mix The exploitation of natural resources is connected with performance mining excavations at different depths. After a certain period of time, those voids break down which, in turn, leads to the slip of upper layers and the so-called landslides forming on the surface. This situation imposes the necessity of basis and sealing rock mass reinforcement. To minimize the risk connected to geotechnical problems on the mining areas, there is a need to use engineering solutions which could improve soil bearing in a universal, economical and efficient way. This leads to the development of new cement slurry recipes used during geoengineering works, especially in the mining areas. Moreover, economic requirements are forcing engineers to use less expensive technical and technological solutions simultaneously maintaining strength properties. An example of such a solution is to use suitable additives to cement slurry which could reduce the total unit cost of the treatment.

This work presents the methodology for analyzing the impact of ground vibrations induced during the drilling of gas/oil exploration wells on the surrounding constructions, as well as on humans and the natural environment. In the primary stage, this methodology is based on measurements of ground vibrations induced by a specific type of drilling system in the so-called reference site. In the next stage, ground vibrations are estimated in similar conditions to another design site, these conditions are assumed for a given drilling system, treated as a vibration source. In both sites, special seismic and geotechnical data are collected to construct numerical models for dynamic analyses. Finally, if it is required, a protection system is proposed with respect to the drilling technology and local conditions. The methodology presented has been tested on the terrain of an active natural gas mine used as the design site, and located in the southeastern part of Poland. The reference site was placed in the terrain of a working drilling system in similar conditions in the central part of Poland. Based on the results of numerical simulations, one may verify the different locations of the drilling rig in the design site with respect to the existing industrial structure. Due to the hazard from destructive ground vibrations, a certain vibroisolation system was proposed at the design site. Based on the results of numerical simulations one could rearrange the components of the drilling system in order to provide maximum security for the surrounding structures.

The authors of the paper describe the way in which the longitudinal working Gussmann was mined in level V and the longitudinal working Kosocice in level VI, which in both cases resulted in a water flux from behind the northern boundary of the salt deposit. Only after concrete dams were seated on both levels, the brine flux was stopped leaving a direct contact of the dams with the pressurized water around the mine. For the sake of controlling water beyond the dams, steel pipelines were conducted through both dams and equipped with gauges before the dams. Their use in a saline environment, the developing corrosion increased the possibility that the tightness of the pipelines would be damaged. For this reason a decision was made to protect the mine by making a tight reconstruction of the safety pillar in both levels along the longitudinal working for about 600 m from the dams eastwards. For this purpose the pipeline injection method was applied. As the volume of voids to be tightly filled equaled to about 3800 m3, the task had to be divided into stages. Because of considerable distances of the liquidated workings from the closest shaft, the sealing slurries were prepared in a special injection center on the surface from where they were transported to the destination with a pumping pipeline through the Kościuszko shaft. The most important aspect of liquidating the end parts of the longitudinal working was to properly select the sealing slurries in view of their best cooperation with the rock mass, and such parameters as tightness, durability and cost. At the end stage of works, both longitudinal workings were equipped with dams, which were sealed up with the hole injection method. The innovative technology was implemented in the Wieliczka Salt Mine to reconstruct the safety pillar in levels VI and V in the most westward workings, the mine was shortened by about 600 m, the length of the ventilation system was reduced, systematic observations and pressure read-outs in dams 3 and 4 were systematically eliminated in dams 3 and 4. In this way the costs were lowered and safety of the mine improved.