The article contains considerations on possible actions directed at increasing productivity of hard

coal mining industry. It is necessary to improve the state of the industry, and ensure its survival. Basic

definitions and measures concerning productivity and management were presented to illustrate examples

referring to a mining enterprise. Then, basing on organizing, one of the management functions, the issue

of productivity in a mining enterprise and its influence on improving effectiveness of operational management,

was analysed. An assumption was presented that solutions concerning identification of sources

and volume of costs, hitherto existing in mining enterprises, ought to be complemented with the planning

function following process approach. It can be the starting point for decisions of economic feasibility of

given deposits, seams or parts of them, before mining operations start, and to control incurred costs in

process approach. The article is summed up with a process algorithm of cost management.

The aim of the article is to present the selected results of analytical investigations concerning

possible directions of reducing the unit production costs in the mining company together with some

results of practical calculations. The investigations emphasize the role of the rate of utilising the

production capacity leading to reducing the unit production costs. The main component having an

essential influence on the unit production costs are the fixed unit costs. Two basic indices of a crucial

meaning for searching for possibilities leading to decreasing the unit production costs are assumed.

The first index (w1) is a measure of the rate of utilising the production capacity, the second one (w2)

concerns the fixed costs coincided with the unit of the production capacity. Theoretical considerations

concerning the mathematical modelling of the unit production costs as the values depending on the

rate of utilising the production capacity and the fixed costs coincided with the production capacity

unit, are presented in the first part of the paper. The rationalisation criteria of the mine unit production

costs are formulated. These criteria can constitute the elements of restructuring program for the mining

company. The calculation example with the use of the practical input data shows the impact of the

rate of utilising the production capacity on the mine unit production costs. In the example two variants

of annual working time are taken into account. Results of appropriate calculations are presented and

analysed in an aspect of reducing unit costs of production as a result of increasing rate of utilising the

mine production capacity.

This article presents the results of studies assesing the significance of the most important macro- and microeconomic factors affecting investors’ propensity to invest in mining. The Polish mining industry in recent years has seen intensive restructuring processes which have considerably affected the status of fixed assets required for the exploitation of useful minerals. In order to efectively manage technological progress in mining plants, it is necessary to understand the role of individual, variable factors influencing investors’ propensity tomake specific expenditures. In the analysis, mathematical statistics and econometric modelling methods were applied to determine the nature of correlations between the values studied and their significance. This examination applied statistical data accumulated by economic entities from 2000–2010. A linear econometric model waspresented illustrating the relationship between capital expenditure in mining and such indicators as fixed assetsvalue, GDP, real interest rate, consumption levels of fixed asset components in mining, and various other factors. Structural parameters of a function specifying the level of investment expenditure can be determined based on statistical data which has been appropriately processed so that the model constructed reflects the economic process studied in relevant way.

Such a model is not free of defects typical in statistical models; however, it simultaneously enables one toobtain valuable information concerning the impact of the factors studied on the value of such expenditure, and the theoretical possibilities to exchange the specific quantity of one factor for another factor. In the final version of the model, it is often sufficient to include only these independent variables which contribute the most essential information to the independent variable. This often simplifies the final form of the model without simultaneous limiting of its importance in explaining the economic phenomenon studied and the possibilities of its practical application. In the final selection of significant variables captured in the model, the method of information capacity indicators was used.

The introduction of the article presents the problem of interpreting the level of fire hazard basing on Graham’s ratio, which, in certain ranges of the value of its denominator, may be wrong. The range of credibility for the index is also discussed. The issue of nitrogen inertisation and its influence on the value of the discussed index is also addressed. To determine the influence, two statistical samples were set. They consisted of the results of precise chromatographic analyses of the air samples collected in the longwall areas which were not subjected to inertisation and in the areas where nitrogen was applied as the inert gas. Then, with Student’s t-test, there was conducted a comparative analysis of both groups with regard to the equality of the average concentrations of gases emitted in the coal self-heating process. At the end, there were developed criteria for the application of Graham’s ratio for the air samples of the increased content of nitrogen, which, according to the discussed index, did not indicate the occurrence of an endogenous fire hazard.

The paper analyzes the impact of potential changes in the price relation between domestic and imported coal and its influence on the volume of coal imported to Poland. The study is carried out with the application of a computable model of the Polish energy system. The model reflects fundamental relations between coal suppliers (domestic coal mines, importers) and key coal consumers (power plants, combined heat and power plants, heat plants, industrial power plants). The model is run under thirteen scenarios, differentiated by the ratio of the imported coal price versus the domestic coal price for 2020–2030. The results of the scenario in which the prices of imported and domestic coal, expressed in PLN/GJ, are equal, indicate that the volume of supplies of imported coal is in the range of 8.3–11.5 million Mg (depending on the year). In the case of an increase in prices of imported coal with respect to the domestic one, supplies of imported coal are at the level of 0.4–4.1 million Mg (depending on the year). With a decrease in the price of imported coal, there is a gradual increase in the supply of coal imports. For the scenario in which a 30% lower imported coal price is assumed, the level of imported coal almost doubles (180%), while the supply from domestic mines is reduced by around 28%, when compared to the levels observed in the reference scenario. The obtained results also allow for the development of an analysis of the range of coal imports depending on domestic versus imported coal price relations in the form of cartograms.

The extraction of mineral deposits is usually charged with additional taxes or royalty fees that go beyond the general income tax. As a rule, countries prefer stable sources of fiscal revenues based on the volume of raw material extraction, and investors prefer models based on profit tax, i.e. taking operating costs and risks lower than the expected profitability of the project into account. As a rule, too high a burden for the mining sector affects investors’ decisions regarding the introduction of new investments. There are a number of examples where excessive fiscal burdens force investors to move to countries with more favorable tax systems. An analysis of various forms of taxation of mining enterprises around the world has been presented and compared with the system implemented in Poland. Usually, the countries that apply the royalty fee in the mining sector at the same time introduce a number of adaptation mechanisms. This is crucial for new investments due to the fact that they may to some extent compensate for the high costs of transition from the investment to the operational phase. In most cases, several incentive mechanisms are used at the same time, e.g. the accelerated settlement of investment expenditures and the unlimited settlement of losses. The copper and silver mining tax introduced in Poland increased the discounted effective tax rate (ETR) from 38.5% to 89% for the entire investment period, which resulted in a 11-year return on investment, as well as a drop in the internal rate of return (IRR).There are currently no mechanisms in Poland which would balance the burden of this tax for a new investor. In order to balance the extraction tax for certain minerals in terms of the IRR and ETR key indicators, the introduction of several adaptation mechanisms has been proposed. For new investments the most essential mechanism is the preferential settlement of capital expenditures incurred in the pre-production phase of an investment. The others include accelerated amortization, the ability to deduct certain expenses for the exploration phase from the tax base, along with an extended tax loss settlement period, or a mechanism for deducting a certain percentage of investment expenses directly from the tax.

The mines play an important role in the economic growth of countries since they are suppliers to many industries. In addition to the economic growth, the mines positively affect the social development factors such as the employment creation, the development of rural areas, building new roads, and etc. But sometimes it may lead to the negative environmental, and social impacts. Therefore, the mining activities should be carefully monitored for the concept of sustainable development. In this paper, a fuzzy Best-Worst Method based approach is developed for the evaluation of an iron mine. The case study, Sangan iron ore mine is one of the biggest mines, located in a rural area in the north eastern of Iran. Three factors including the economic, environmental, and social parameters were considered as main sustainable development criteria. The sub-criteria for each mentioned factor were then extracted from the literature as well as knowledge expert’s opinions. In the proposed approach, each sub-criterion was carefully weighted using the fuzzy Best-Worst method and scored by 12 experts. Afterwards, the sustainability score was defined as the summation of final fuzzy scores which was gone under a defuzzification process. The performance evaluation was calculated using this sustainability score resulted to a score of 0.626 out of 1, indicating its acceptable performance. The results showed that the mine performs well in terms of the economic benefits, rate of return, exploration capacity, and stockholders’ rights, but in the environmental management systems, water discharge, recreation and tourism aspects, it does not play well. The results of the implementation of the proposed approach showed the efficiency and effectiveness of the proposed approach that is confirmed by experts.

The continuous improvement in the industries and organizations hinges upon the evaluation of their performance. In fact, the performance evaluation assists organizations to identify their strengths and weaknesses and, accordingly, enhance their efficiency. As soon as the concept of sustainability was propounded in the engineering based industries, the performance evaluation got more importance due to the environmental issues and social concerns along with the economical aspects. Therefore, this paper is an attempt to propose an approach based on fuzzy best-worst method (BWM) and fuzzy inference system (FIS) in order to evaluate the performance of an Iranian steel complex in terms of sustainability concept. In the proposed approach, the weights of some selected criteria were determined by fuzzy BWM method and, then, the score of the under study industry was calculated in terms of economic, environmental, and social aspects. At the end, an FIS was developed to calculate the final score of the intended industry. In order to check the efficiency of the proposed approach, its performance was measured using expert knowledge as well as real data of a steel complex in Iran. A moderate to high performance has been achieved for the understudy case through conducting the proposed approach. It was suggested that the industry should focus on the criteria with both high weights and low evaluated scores (for example the environmental management technologies and knowledge criterion) to increase its performance evaluation score. The obtained results were indicative of the efficiency of the proposed approach.

Most EU member states have taken measures to implement the principles of sustainable development. Mineral extraction in Europe has become more difficult, since most member states have taken measures to implement the principles of sustainable development. The industrial minerals sector provides important mineral commodities for the industries. The general situation of minerals supplying in Europe is provided by a strong position of aggregate sector. The paper evaluates the development of mineral extraction in the Visegrad group of EU countries with the aim to find the position of the mining industry in the V4 countries and its contribution to the European mining industry, regarding the sustainability of mining. A task of sustainability assessment is the evaluation of the V4 mining sector’s contribution to the European economy and finally to assess the risks and obstacles for mining industry development. Due to the mentioned present state of minerals supplying in Europe, this is evaluated with economic and environmental significance of materials, connected with development of mineral production and critical mineral Raw Materials in EU, compared with worldwide situation, followed by the prediction of mineral production. The third part is orientated towards the evaluation of raw materials used in the individual V4 countries. The situation of mineral production is evaluated especially in the V4 region. Thre results show that despite the fact that there is an obvious certain boom and annual growth of mining volumes in the V4 countries, the growth does not mean the mining industry follows sustainable development. There is a vast space for the industry to improve. The further evaluation of state minerals demands the consideration of risks and obstacles in mining business and the environment impact.

In recent years, the Vietnamese coal mining industry has observed a dynamic increase in both its production and efficiency. In Vietnam, the most precious type of coal is anthracite, which is found in the Quang Ninh province. Industrial anthracite deposits are estimated to be over 2 billion Mg. At present, coal deposits are extracted mostly by the underground method. Coal production is gradually increasing in the underground mines in the Quang Ninh area and it is expected to constitute about 75% of the country’s total coal production in 2030. This involves an increase in the number and length of underground workings.

Cam Pha is the largest coal basin of Vietnam, located in the Quang Ninh province. So far, the yearly length of underground workings driven in underground mines in the Cam Pha basin is roughly 90÷150 km. About 84 % of these underground workings are supported by the steel arch support made of SWP profile. A similar situation can be observed in Russia, Ukraine, China, India and Turkey. In addition, the average length of repaired underground workings in the Cam Pha basin constitutes approximately 30% of the total length driven . The main cause was reported is loss of underground workings stability. This requires significant material and labour costs as well as the cost of replacing damaged elements. Additionally, it disturbs the continuity of the mining operations.

This article presents the results of the numerical modelling of the rock mass around underground workings driven in typical geo-mining conditions for underground coal mines in the Cam Pha basin, supported by the steel arch support made of SWP and V profiles. As a result of the conducted analyses, the range of failure zone of the rock mass around underground workings and the distribution of reduced stress in the steel arch support elements were determined. The effort states of the steel arch support made of SWP22 profile and V21 profile were compared. The simulations considered different inclinations angle of coal seam, following the structure of the rock mass in the Cam Pha basin. The analysis was carried out using the based-finite difference method code, FLAC2D. Based on the obtained results, actions for improving the stability of underground workings driven in the underground mines of the Cam Pha basin were proposed.

The Polish power generation system is based mostly on coal-fired power plants. Therefore, the coal mining sector is strongly sensitive to changes in the energy sector, of which decarbonization is the crucial one. The EU Emission Trading System (EU ETS) requires power generating companies to purchase European Emission Allowances (EUAs), whose prices have recently soared. They have a direct impact on the cost efficiency of hard coal-fired power generation, hence influence the consumption of hard coal on the power sector. In this context, the objective of this paper is to estimate the hard coal consumption in various regions of Poland under selected forecasts of the EUA price. To investigate this question, two models are employed:

 - the PolPower_LR model that simulates the Polish power generation system,

 - the FSM _LR model that optimizes hard coal supplies.

Three scenarios differentiated by the EUA price are designed for this study. In the first one, the average EUA price from 2014–2017 is assumed. In the second and third, the EUA prices are assumed accordingly to the NPS and the SDS scenario of the World Energy Outlook. In this study we consider only existing, modernized, under construction and announced coal-fired power generation units. The results of the study indicate that regardless of the scenario, a drop in hard coal consumption by power generation units is observed in the entire period of analysis. However, the dynamics of these changes differ. The results of this analysis prove that the volume of hard coal consumption may differ by even 136 million Mg (in total) depending on the EUA prices development scenario. The highest cumulated volume of hard coal consumption is observed in the Opolski, Radomski and Sosnowiecki region, regardless of the considered scenario.

Mining activities from exploration to final material handling up to shipment pass through various stages where environmental pollution results. Mining method can and should be selected in such a way that their impact on individuals and environmental to be minimized. Until now, different mining specialists have carried out many studies on mining method selection. Unfortunately neither of previous approaches takes into account of the environmental consideration and methodology for assessment of environmental impacts criterion. This paper discusses environmental impacts of mining operations associated with different mining methods. For this purpose, the Folchi approach was modified for environmental impact assessment which associates the mining methods inherently and developed of a procedure to assist a selecting of mining method. Firstly, the general and explanatory information about effects of mining on the environmental pollution are given in the paper. Moreover field and purposes of the study are introduced. The paper presents an environmental assessment for different mining methods. And, secondly, the impacts of each mining methods on environment are focused and discussed. Finally, some concluding remarks are made and the related applications for the mining method selection are discussed by using in a case study. As the main advantage, this new algorithm takes several environmental issues and their interaction takes into consideration for environmental assessment of a mining method selection.