The quarry in Lubiechowa has been attracting mineralogists as well as amateur rock-collectors for years. What undiscovered secrets does it still hold?

Lower Carboniferous limestone has been extracted in the “Czatkowice” open-pit hill-slope quarry in southern Poland since 1947, for the needs of metallurgical and building industries, as well as farming. We can distinguish two aquifers in the Czatkowice area: the Quaternary porous aquifer and the Carboniferous fissure-porous one. Two vertical zones representing different hydrodynamic characteristics can be indentified in the Carboniferous formations. One is a weathering zone and the other one the zone of fissures and interbedding planes. Groundwater inflows into the quarry workings have been observed at the lowest mining level (+315 m above the sea level (asl)) for over 30 years. This study concerns two hypotheses of the sources of such inflows originating either from (a) the aeration zone or from (b) the saturation zone. Inflows into the quarry combine into one stream flowing gravitationally to the doline under the pile in the western part of the quarry. This situation does not cause a dewatering need. Extending eastward mining and lowering of the exploitation level lead to increased inflows.

Road construction has been an ongoing engineering practice throughout human history. Although road construction technologies have changed over time, the raw material used has not changed for centuries, and it seems that it will not change in the upcoming centuries. Although some standards are used to determine the aggregate quality in road construction works, it is often complex and laborious to identify the aggregates that best meet the standards. Long-lasting and high-quality roads can be built and the most suitable aggregate is selected for the road. This study aims to select the most suitable aggregates used in hot-mix asphalt pavement production for road construction. In this study, multi-criteria decision-making methods were used for the selection of the aggregate that provides the best conditions. Aggregates used in constructing roads within the provincial borders of Ankara are produced from six stone quarries. To rank these aggregates and determine the ideal quarry for hot-mix asphalt production, the analytical hierarchy process (AHP) and the technique for order preference by similarity to an ideal solution (TOPSIS) method, which are multi-criteria decision making (MCDM) methods, were used. The results obtained from the tests on aggregates and hot-mix asphalts (HMA) were compared with the the best results based on the maximum and minimum limits determined in the standards. By comparing the the best results of the standards with the test results of the aggregates, weight scores were made for each test. Weight scores were scored and classified using the AHP and TOPSIS multi-criteria decision-making methods. As a result, the aggregate with the highest score and the quarry area represented by the aggregate were determined as the most suitable for hot-mix asphalt construction.

The subject of the research presented in this paper were financial results of mining industry enterprises (PKD 5 – P olish C lassification of A ctivity – “Mining of coal and lignite”) in 2007–2019. The research was conducted using relative and absolute financial measures, forming an extensive and coherent set of features characterizing their financial condition. The purpose was to measure and evaluate the efficiency of examined enterprises operation, considered as an attribute of development as well as factors describing and determining it. This evaluation was made against the background of ongoing restructuring processes taking into account their potential effects.

The article presents the course of the process of adapting P olish hard coal mining to market economy conditions after 1989. The process can be conventionally divided into several periods. The scope and intensity of changes in the mining industry followed the subsequent government programs for mining industry restructuring.

The lignite mining has not implemented any specific restructuring programs. The remedy processes were mainly related to organizational and ownership changes.

In relation to operation efficiency and value creation three turning points in the development path of enterprises were highlighted – 2011, 2015 and 2017, while the period of strong deterioration of results occurred in 2011–2015. I t was proved that restructuring processes did not affect the operating return on sales. However, there was a strong relation between changes in economic conditions on the coal market (prices) and the accumulation rate.

In the defunct Górka heading there is both a waste disposal site with an area of 6.7 ha containing approximately 600 000 m3 of waste generated in the course of aluminum oxide production and a pond with an area of 3 ha and depth ofup to 15 m containing about 400 000 m3 of effluent (leachate water). The reservoir is filled with infiltrates flowing in from the above-mentioned disposal site at a rate - 130 m3/day. The subsidence of the pond bottom and infiltration of solutions into the Triassic and Jurassic water resources, estimated at - 40 m3/day, is a cause of serious concern. The basic problem of the effluents in the Górka pond is their high alkalinity (pH 12-14) and variable pollutant content, the level of which increases with the pond's depth. The proposed solution involves pumping out and treating about 500 000 m3 of effluents retained in the Górka reservoir. The effluents would be treated in a reverse osmosis plant using a process which has so far been verified on a quarter-commercial scale. The treatment process by-product would be discharged into the Ropa stream. The brine solution (containing - 25% NaCl), would be solidified. The next stage after pumping would be the utilization of approximately 50 000 m3 of bottom slurry. Highly alkaline slurries would be utilized in the production of self-solidifying mixtures. These mixtures would be used to scal the bottom of the Górka reservoir and part of the edges of the defunct quarry, according to requirements. The next stage would involve outcropping the feed-water sources located in the northern section of the old heading to reconstruct the original flow system from the sources to the Ropa River. The excavated solid waste would be relocated into the remainder of the disposal site containing solid aluminium waste. The surface ofthc site would be scaled and then reclaimed. The final stage involves macrolcvclling of the site into an amphitheatre system, outcropping the fertile soil layer, constructing a lake and streams, and finally land reclamation of the whole site.

Stemming plugs are one of the widely used accessory in surface mining operations. Stemming plugs assist conventional stemming material in gas retention and help in better fragmentation and explosive utilization. Effective use of the stemming plugs results in economic benefits and enhance the efficacy of the project. Economic and productive viability of stemming plugs have been conducted in depth by different researchers. Addition of stemming plugs to a new system requires ergonomic challenges for operators conducting drilling and blasting operation. Induction of a newer product in already established system is subject to overall positive feedback. This work investigates ergonomics of three different stemming plugs introduced to a limestone quarry in Pakistan. The stemming plugs were evaluated based on extra time needed, workers feedback, failures during operation, recovery time after failure and number of extra equipment required to carry out the operation. Points based matrix was established with likeliness of each plug and based on overall scores stemming plug 1 was most acceptable followed by stemming plug 3. Stemming plug 2 was disliked by operation and did not reach the level of acceptability of operators. This work will help stemming plug making industry in adapting to best practices by incorporating ergonomics of plugs in designing. Literature shows no previous work on ergonomics of stemming plugs.