Gas-dynamic characteristics of the host rocks of Mir pipe mine field deep horizons

The purpose of the research is to study the gas-dynamic characteristics of deep horizons of the Mir pipe mine field to ensure industrial safety under construction and production resumption at the field. The study is based on the interval field experiments carried out during drilling and subsequent study of the core. The main gas-dynamic parameters of the deep horizons of the field were studied during the drilling of pilot wells that enabled to perform interval determination of the flow rates of formation gases using packers and complex research equipment, gas sampling for the determination of chemical composition of gases, and gas logging. The conducted works resulted in the formulation of the gas-dynamic characteristic of the Tolbachan formation within the mine field of the Mir pipe. Reservoir intervals were identified and the nature of their fluid saturation was determined. The chemical composition of formation gases was clarified and gas release nature and intensity were studied both under drilling and interval testing. The result of the research carried out was identification of zones with different fluid manifestations, as well as comparison of the field under investigation with the previously studied International pipe. The results of the conducted research works will form the basis for performing design forecast calculations, as well as for making the main design decisions under construction of capital mine workings, especially in terms of advanced degassing of the mountain range. Consideration of the zones identified within the Tolbachan formation, which feature different nature of fluid saturation, will allow to take into account and minimize possible adverse factors.

Forecasting Underground Water Dynamics within the Technogenic Environment of a Mine Field: Case Study

The objective is to analyze the dynamics of the underground water of a mine field based on the study of the geofiltration process of the rock mass disturbed by mining to achieve safe extraction operations as well as subsurface territories at the stage of the mining enterprise closure. Numerical modeling, based on a finite difference method under the conditions of multifactority and definite uncertainty of processes of transformation of technogenic environment of a mine field, helps solve a problem concerning underground water dynamics forecasting. A hydrodynamic model of the M.I. Stashkov mine was developed while solving option series of epignosis problems in terms of the chronology of mine field stoping. The abovementioned made it possible to identify regularities of the history of filtration, the capacity parameters of rock mass and the expansion of areas of heightened hydraulic conductivity as well as to evaluate qualitatively the water balance components of a carbonic watered formation and an overlying one. The stage of mining closure helped obtain the forecasting hydrodynamic solutions. The efficiency of measures, concerning reduction of water ingress into mine workings and the mitigation of surface ecological effects of mine flooding was evaluated quantitatively. It was determined that implementation of the water control procedures makes it possible to perform a 10–38% decrease in water ingress. In this context, they may be applied both independently and simultaneously. In terms of mine closure and flooding, a period of complete underground water recovery takes three years; in the process, surface zones of potential waterlogging and swamping are developed within the floodplain of Samara River, located at the territory of Western Donbas (Ukraine). The scientific novelty is to define regularities of hydraulic conductivity transformation of the rock mass of a mine field starting from the mine working roof fall, up to its compaction during the mine operation period. To do that, nonstationary identification problems were solved, using numerical modeling. The abovementioned makes it possible to improve the reliability of hydrodynamic prognoses and develop technological schemes to control water at the state of the mine closure.

ASSESSMENT OF FORECAST ACCURACY DANGEROUS PROPERTIES OF COAL LAYERS BY THE DEGREE OF METAMORPHISM OF SOLID FOSSIL COALS

In the normative base of Ukraine for the safe mining of coal seams, only five indicators of the degree of metamorphism are used to predict the manifestation of their hazardous properties during mining operations: mass release of volatile substances during thermal decomposition of coal without air (Vdaf) access to characterize coal; volumetric yield of volatile substances daf V V to establish the distinctive properties of anthracites; logarithm of electrical resistivity (lg); the thickness of the plastic layer (y) and the grade of coal (M) for predicting the outburst hazard of seams. When developing regulatory documents, it was assumed that these criteria for assessing the degree of coal metamorphism remain constant within one mine field. Their values, as mining operations show, are influenced by the location of the coal sampling site in relation to the distance from relatively large geological disturbances or the boundaries of the gas weathering zone. In most cases, the boundaries of mine fields are usually relatively large geological faults. The proximity of the locations of coal sampling points to them influences the obtained results of evaluating the properties of mine layers. Аdjusting indicators (Vdaf, daf V V , lg, y ,M) for individual mines on the possible impact of geological disturbances, the depth of the mining robot and the distance from the zone of gas weathering, according to the requirements of regulatory documents. For this reason, it is of scientific and practical interest to establish the possible ranges of change in the indicators of the degree of metamorphism of coal within the same mine layer. The results of research in this direction are relevant, as they are necessary to improve the regulatory framework for the safe mining of coal mines. A possible change within a separate mine field was considered using the example of the indicator Vdaf as the most studied at present. According to a specially developed methodology, the analysis involved data on 2193 mines from different coal basins. Most of them belong to the mines of the Donetsk basin (1773). The rest of the basins account for information on 460 mine layers, including data on 46 mine layers for the Lvov-Volyn basin.

IMPROVEMENT OF THE TECHNOLOGY OF DEVELOPMENT OF RESERVES OF THE EMISSION-HAZARDOUS FORMATION OF THE КРII STRATUM IN THE CONDITIONS OF THE EUROCHEM USOLSKIY POTASH MINE

This article presents the results of the authors' research on the construction of a pre-diction map with the division of an explosive potassium formation of the KPII stratum into haz-ardous and non-hazardous areas in the conditions of the mine field of the EuroChem Usolskiy potash mine, it is discovered that the decision rules developed for the other potash mines of the Verkhnekamskoye potash deposit are fundamentally unsuitable for the site concerned and re-quire revision, options of improvement the decision rule are proposed. Recommendations for safe mining operations, implicating a change of the existing mining technology, are presented at the end of the article.

Estimation of Gas Bearing Capacity and Gas Dynamic Behaviour of Rocks of Salt and Shaly-Carbonate Rock Units in the Mine Field of the Mine of the Second Mining Department of Belaruskali JSC

The paper presents results of quantitative estimations of gas bearing capacity and gas dynamic behaviour of shaly-carbonate and salt rock units along the geologic profile of the Starobinsky potash field between the III and IV potash horizons. Underground experimental studies of the gas bearing capacity and gas dynamic behaviour of the shaly-carbonate and salt unit rocks were conducted in the slopes opening the IV potash horizons in the mine field of the mine of the Second Mining Department of Belaruskali, JSC. The underground experimental research procedure provided for quantitative estimation of the following indicators: nonassociated gas bearing capacity, initial gas emission rate and gas pressure of rocks in the 12th, 10th and 8th shalycarbonate units, as well as the 11th and 9th salt units. Based on the underground experimental research data, a quantitative estimation of the gas bearing capacity and gas dynamic behaviour of rocks in the 12th, 10th and 8th shaly-carbonate units as well as the 11th and 9th salt units was performed. Identified were the most gas-bearing beds of rocks in the shaly-carbonate and salt rock units, as well as the pattern of changes in the gas bearing capacity and gas dynamic behaviour of rocks in the geologic profile between the III and IV potash horizons.