One of the most critical aspects of mine design is to determine the optimum cut-off grade. Despite Lane’s theory, which aims to optimize the cut-off grade by maximizing the net present value (NPV), which is now an accepted principle used in open pit planning studies, it is less developed and applied in optimizing the cut-off grade for underground polymetallic mines than open pit mines, as optimization in underground polymetallic mines is more difficult. Since there is a similar potential for optimization between open pit mines and underground mines, this paper extends the utilization of Lane’s theory and proposes an optimization model of the cut-off grade applied to combined mining-mineral processing in underground mines with multi-metals. With the help of 3D visualization model of deposits and using the equivalent factors, the objective function is expressed as one variable function of the cut-off grade. Then, the curves of increment in present value versus the cut-off grade concerning different constraints of production capacities are constructed respectively, and the reasonable cut-off grade corresponding to each constraint is calculated by using the golden section search method. The defined criterion for the global optimization of the cut-off grade is determined by maximizing the overall marginal economics. An underground polymetallic copper deposit in Tibet is taken as an example to validate the proposed model in the case study. The results show that the overall optimum equivalent cut-off grade, 0.28%, improves NPV by RMB 170.2 million in comparison with the cut-off grade policy currently used. Thus, the application of the optimization model is conducive to achieving more satisfactory economic benefits under the premise of the rational utilization of mineral resources.

Gas bubbles in the ocean are produced by breaking waves, rainfall, methane seeps, exsolution, and a range of biological processes including decomposition, photosynthesis, respiration and digestion. However one biological process that produces particularly dense clouds of large bubbles, is bubble netting. This is practiced by several species of cetacean. Given their propensity to use acoustics, and the powerful acoustical attenuation and scattering that bubbles can cause, the relationship between sound and bub-ble nets is intriguing. It has been postulated that humpback whales produce ‘walls of sound’ at audio frequencies in their bubble nets, trapping prey. Dolphins, on the other hand, use high frequency acous-tics for echolocation. This begs the question of whether, in producing bubble nets, they are generating echolocation clutter that potentially helps prey avoid detection (as their bubble nets would do with man-made sonar), or whether they have developed sonar techniques to detect prey within such bubble nets and distinguish it from clutter. Possible sonar schemes that could detect targets in bubble clouds are proposed, and shown to work both in the laboratory and at sea. Following this, similar radar schemes are proposed for the detection of buried explosives and catastrophe victims, and successful laboratory tests are undertaken.

All the restructuring programs that have been implemented in Polish bituminous coal mining as a primary way to reduce mining costs relied on the increased concentration of mining operations. Those efforts especially involved a significant simplification of existing or newly developed structures for accessing or cutting the deposits intended for extraction; implementation of advanced mining technologies, and upgrading of machines used in mine faces. However, in order for these to deliver the expected results, it is important to organize mining operations in such a way so that those advanced, and usually very expensive, mining-related fixed assets – machinery and equipment – are used sensibly. In order to define a reasonable production capacity of each longwall face, it is necessary to apply various criteria related to the mining and technical aspects, occupational safety, and organizational and economic aspects. Only then will it be possible to evaluate the expected effects in the field of concentration of mining in a mining company and in the mines which form part of such enterprises. Decisions in this respect should always be made at the planning stage, based on analysis results. The aim of this article is to explore the factors involved in concentration-related decision-making in mining companies, including the underlying mining/technical, organizational, and economic/ /financial aspects. A mining company is understood as a group of related mines, the primary business operations of which include bituminous coal mining, processing, and trading.

The current rockburst hazard conditions in the copper mines are the consequence of mining-induced seismicity of the rock strata whilst the majority of registered rockbursts have been caused by high-energy seismic events. T he analysis of seismic activity in recent years indicates that the region of the Rudna mine is the region of the highest seismic activity. This paper is an attempt at evaluating the seismicity levels in the Rudna mine in the period from 2006-2015, within the entire mine and in its particular sections. Key parameters of seismic activity include the number of registered seismic events, total energy emission levels, and a unit energy factor. The variability of Gutenberg -Richter (GR) parameters are analyzed and the epicenters’ locations are investigated with respect to the stope position. T he distinction is made between low-energy (103 ≤ As < 105 J) and high-energy (As ≥ 105J) seismic events ahead of the stope, in the opening-up cross-throughs and in the gob areas. It appears that the risk level of a high-energy event occurrence in the R udna mine has not changed in recent years and has remained on a high level whilst the differences in seismic activity, in particular mine sections, are attributed to the varied extraction height and varied thickness of rockburst-prone carbonate layers in the roof of the copper ore deposit. The analysis of the epicenters’ locations with respect to the stope reveals that no matter what the seismic energy levels, the largest number of rockbursts are registered in the opening-up cross-through zone. Low-energy tremors are mostly located in the gob areas, high-energy events occur mostly ahead of the stope. T hus, the evaluation of the seismicity conditions in the Rudna mine seems to positively verify the relationship between the number of registered events and the levels of generated seismic energy, taking the local geological and mining conditions and the specificity of the room and pillar mining method into account.

Coal mining activities carried out for 200 years in Upper Silesia have had a negative effect on buildings. T his impact is in all cases related with continuous deformations of the surface and in certain cases with discontinuous deformations (mostly cave-ins), changes in water relations and mining tremors. T he paper presents an evaluation of the impact of a mining activity on a building situated in the Upper Silesian Coal Basin. T he building was affected by continuous deformations and mining tremors. Calculations were made of the values of deformation rates by means of Budryk–Knothe’s theory, which were partly verified on the basis of the results from geodetic measurements. An analysis of the velocity and acceleration of basement vibrations caused by mining-induced tremors was also conducted. T he conclusions included a high consistency between the results obtained on the basis of calculations and the values obtained by means of PGA and PGV measurements. In the case of tremors with the highest energy in the hipocentrum, there an empirical formula allowing for calculation of PGA value in given geological and mining conditions was also proposed. T he application range of the formula mentioned above is obviously limited only to the conditions in consideration. The presented conclusions indicate that at present, sufficiently precise methods, allowing for calculations for practical purposes, not only of deformation indices’ values, but also of PGV and PGA values, presently exist.

Mining-induced seismicity, particularly high-energy seismic events, is a major factor giving rise to dynamic phenomena within the rock strata. Rockbursts and stress relief events produce the most serious consequences in underground mines, are most difficult to predict and tend to interact with other mining hazards, thus making control measures difficult to implement. In the context of steadily increasing mining depth within copper mines in the Legnica-Głogów Copper Belt Area (Poland) alongside the gradually decreasing effective mining thickness, a study of the causes and specificity of mining-induced seismicity in specific geological and mining settings may improve the effectiveness of the prevention and control measures taken to limit the negative impacts of rockbursts in underground mine workings, thus ensuring safe working conditions for miners. This study investigates the presumed relationship between the mined ore deposit thickness and fundamental parameters of mining-induced seismicity, with the main focus on the actual locations of their epicenters with respect to the working face in commonly used room-and-pillar systems. Data recalled in this study was supplied by the O/ZG Rudna geophysics station. Based on information about the actual ore deposit thickness in particular sections of the mines (Rudna Główna, Rudna Północna, Rudna Zachodnia) and recent reports on seismic activity in this area, three panels were selected for further studies (each in different mine region), where the ore deposit thickness was varied (panel G-7/5 – Rudna Główna, panel XX/1 – Rudna Północna, panel XIX/1 – Rudna Zachodnia). Data from seismic activity reports in those regions was used for energetic and quantitative analysis of seismic events in the context of the epicenter location with respect to the selected mining system components: undisturbed strata, working face and abandoned excavations. In consideration of the available rockburst control methods and preventive measures, all events (above 1 × 103 J) registered in the database were analysed to infer about the global rockburst hazard level in the panel and phenomena induced (provoked) by blasting were considered in order to evaluate the effectiveness of the implemented control measures.

The article is an analysis of the content of the reports of the national mining companies and vertically integrated operators in the energy value chain, in light of the guidelines of global standards of corporate social responsibility (CSR – Corporate Social Responsibility). A verification of the review of the literature and reports of selected companies in terms of non-financial data publication was conducted, that is information which is based on ES(G) (E – Environment; S – Social; G – Governance), especially considering all environmental and social aspects. It was also indicated which selected mining companies prepare integrated reports (financial and non-financial data), in line with the GRI (Global Report Initiative) guidelines and G4 Mining and Metals – the document contains a set of disclosures for use by all organizations in the Mining and Metals sector. According to the author, universal access to non-financial data expanding the circle of stakeholders and can mitigate the negative public opinion towards the mining industry. Integrated reporting is a new experience for Polish mining companies and vertically integrated energy groups reporting sent to various stakeholder groups, using the GRI guidelines. The analysis showed that only two domestic companies out of the 10, i.e. LW Bogdanka S.A. and KGHM Polska Miedź S.A. submitted the report for 2015, based on the indices dedicated to the, „mining and metals” Industry. The selection of companies has been dictated by their significant share in the mining industry in Poland. The article indicates skipping important aspects of the business activities of mining and vertically integrated enterprises, which should be a necessary part of the reports (due to the obvious impact of mining on the environment and society). It refers to the GRI G4 Mining and Metals guidelines as the indicators which are additional tools to reporting on sustainable development. The purpose of this article is to point out important aspects of the mining companies and vertically integrated enterprises which are omitted and, in the opinion of the author, should be the components of those reports.

Since the 1970s, the Legnica-Głogów Copper District has an area of intensive mining of copper. Mining activities resulted in the appearance of induced seismic activity. This situation caused the necessity of setting an underground seismological network. In the mid-1990s, due to the great damage of objects on the surface caused by the ground vibrations due to mining tremors, a surface strong motion seismic network equipped with accelerometers was created. They monitor the vibration levels of both the land and the buildings themselves. This contributed to a better knowledge of the nature of ground vibration and the resistance of objects. In recent years, anthropogenic threats, which include seismicity induced by mining activities, are arousing more and more interest. To be able to develop test methods for seismic source physics, the analysis of the impact of vibrations on the surface and the seismic hazard, network measurement should also be developed and modernized. In the years 2014–2015, the IS-EPOS “Digital research space of induced seismicity for EPOS purposes” project, extended the LUMINEOS modern seismological network presently consisting of 15 seismometers and 10 accelerometers, with the possibility of additional further expansion. The data obtained from the LUMINEOS network complements the existing underground mining network and surface strong motion network. This allows for an advanced seismic analysis.

The article discusses problems related to rules and regulations determining compensations for the mining usufruct of mineral deposits covered by the so called “state mining ownership”. Specific acts of law framing agreements on mining usufruct between government and mining enterprises were analyzed. Rules and algorithms applied to calculate an appropriate compensation are evaluated leading to several conclusions, including the one about lack of a direct legal grounding for them. Such a situation creates disputes and may be risky for all involved. It was also indicated that, in parallel, the State lets another class of mineral deposits, namely the ones owned as a result of real estate ownership and the related Civil Code regulations confirmed by the mining law. In such cases, a mining entrepreneur gets usufruct of a real estate, but only the one with mineral rights. Subsequently a comparison of the rules and algorithms established for determining compensation for mining usufruct and for usufruct of real-estates comprising rights for mineral assets was performed. Arguments for a far going harmonization between these two were put forward. This implies that a starting point for determining any compensation has to be a valuation of a relevant mineral deposit market value as opposed to any universal, however complicated, prescribed algebraic formula. Such a process is complicated and demands competences in geology, mining and finance. Consequently, regulations set in the Polish Mineral Asset Valuation Code shall be applied to both a running a valuation process and indicating competent persons. As a result, recommendations leading to correlate rules applied in both cases are put forward including the adoption of mineral asset valuation as a fundament to determine the level of compensation for the mining usufruct. The closing section contains recommendations regarding necessary changes in the legal framework.

The problem of deposit protection and the process of liquidation of mining plants does not find effective solutions in the national law. Nevertheless, this is a very up-to-date issue. This situation prompted the authors of the article to once again analyze these issues. The number of abandoned exploitation sites which were published in the Polish Geological Institute reports should affect the entire licensing system and the state’s raw material policy. As a good host of raw materials, which we have been given by Earth Mother, we cannot allow that the mining licensing system, the liquidation procedures of mining plants without due diligence, result in the lack of protection of these deposits. The rational raw material economy and the ability to exploit it for the future generations, while failing to effectively enforce the site liquidation process makes it necessary to take actions leading to not blocking the mineral deposits in this way. The analysis shows what appropriate actions should be taken. The authors have thoroughly investigated the legal regulations over the past century, compiling them with the current legislation, and pointing out the weaknesses of the system in the field of deposits protection, particularly in the part of the unexploited deposits. Criticism covered both the statutory regulations – Geological and mining law as well as executive acts in the field of deposit protection. A separate analysis was subjected to the procedure of liquidation of the mining plants in the aspect of deposits protection, for mining plants operating on the basis of the Province Marshal’s licenses. The process presented in the flowchart layout clearly shows the weak points of the currently operating system.

Coal mining is one of the most important sectors of the Polish industry. It can be said that the coal is a national raw material. This results in Poland being a pioneer in the European Union in terms of coal mining as well as its use in the production of electricity and heat. There are many companies in Poland which have been established and developed around the coal mining industry aimed at coal extracting. The operations of those companies depends on the condition of the mining companies and their cooperation with them: commercial, service and advisory, called referred to as “mining supporting companies”. The article focuses on the results of a survey carried out in mining supporting companies, such as mining machinery and equipment manufacturers, mining-related service companies and mining-related research and development institutions. The authors evaluated the relationship and dependence of those companies on the mining industry. It was assumed that the measure of the mining supporting companies condition is the overall quantity of public related payments contributed to the state budget and local budgets. In the article, the authors raised the problem of the size of losses for public finances, as a result of the significant limitations of financial flows from the mining companies. The surveyed companies are those associated with the Polish Mining Chamber of Industry and Commerce. As a result, the authors prepared conclusions regarding the dependence of the mining supporting companies on the situation of the mining subsector.

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.

Plastic rocks can creep, therefore the knowledge of the rheological properties of the drilled formations is an important element of the drilling process and when choosing borehole designs. These properties of plastic formations also influence the way in which appropriate drilling technology and drilling mud properties are selected. The article presents the effect of basic rheological parameters of salt from the Fore-Sudetic Monocline deposit on the drilling of boreholes in the mining area of KGHM Polska Miedź, which in the future can be used as a good drilling practice to improve the safety and efficiency of drilling.

The process of drilling in plastic rocks may be hindered. Salt is a plastic rock and in the analyzed rock mass it is deposited at a considerable depth. The caprock exerts big loads on it, beside the temperature in the deposit intensifies the rheological properties of the rock. The creep process causes that the borehole contracts, therefore the knowledge about the rheological properties of the drilled rock is very important for establishing the safe time in which the well may remain uncased. The paper is devoted to the influence of basic rheological parameters of salt bed in the Fore-Sudetic Monocline on the process of drilling of a borehole in the area of KGHM Polska Miedź as these data can be used in drilling practice in the future.

The article presents the methodology for assessing the longevity of hard coal mines. Based on international experts’ assessments, important criteria for determining mine viability have been presented. The results refer to Polish coal mines in the area of the Upper Silesian Coal Basin, however, the methodology itself can be applied to other geological and mining conditions of mines elsewhere.

The results of structural analyses carried out using the MICMAC method for factors related to the mining geo-environment that may determine the longevity of individual hard coal mines are presented. The analyses were based on the results of expert surveys carried out using the Delphi method. The experts participating in the survey came from various countries and had extensive experience related to work or cooperation with hard coal mining. The criterion factors examined were assigned to two systems (groups) for which structural analysis was performed. The first group includes factors related to the level of exploitation hampering, while the second group includes factors related to hard coal quality and the availability of resources. As a result of the analyses the following were determined: the key factors which have the most significant influence on the system, result and goal factors, factors affecting the system and autonomous factors which have little effect on the system.

The obtained results allowed to determine which factors should be taken into account in the process of determining the longevity of a hard coal mine.

Exploitation of hard coal seams by roadway system is applied by two coal mines in southern Poland in Upper Silesian Basin. It is a secondary mining exploitation carries out in safety pillars of urban areas and shafts within mining areas of closed coal mines. Roadway system is the excavation process of gateways which are made in parallel order leaving coal pillars between them. An optimal width of coal pillar makes roadway stable and reduces subsidence of terrain surface. The article presents results of subsidence simulation caused by partial extraction using empirical and numerical methods on the example of one exploitation field of “Siltech” coal mine. The asymptotic state of subsidence was considered after mining ceased in the study area. In order to simulate of subsidence, numerical model of rock mass and model of Knothe-Budryk theory were calibrated. Simulation of vertical displacements in numerical method was carried out using RS3 program by Rocscience based on finite element method. The assumption was made that model of rock mass is transversely isotropic medium, in which panels were designed according to order of extraction of coal seams. The results of empirical and numerical methods were compared with measured values of subsidence at benchmarks along drawn lines (subsidence profiles).