Ensuring Stability of Undermining Inclined Drainage Holes During Intensive Development of Multiple Gas-Bearing Coal Layers

At high rates of production face advance, requirements towards reliable operation of undermining drainage holes get raised. The issue of maintaining high intensity of gaseous seams development under naturally increasing gas content, mining depth and capacity of production equipment poses a problem. The greatest threat comes from the loss of hole stability in the bearing pressure affected zone (in front of the face) and in the intensive shift area of overhanging rock corbels (behind the face). Intensification of air leaks due to deformation of borehole channel leads to impoverishment of removed methane-air mixture and an increasing risk to disturb safe aerogas regime in the mining area. The paper describes a mechanism of how coal-face operations affect the state of underground holes and formation of overhanging rock corbels. A typification of basic kinds of borehole deformations is presented. Authors point out critical disadvantages of the most widely-used technological schemes of gaseous seams development under high load on the production face, which hinder normal operation of a gas drainage system. As a result of research, a dependency of shot hole number, as well as the distance between shot hole axes and the borehole, on the stress state of the borehole outline has been defined more precisely. Basing on that, a formula to calculate drilling parameters of the discharge hole system has been suggested. Implementation of these measures will allow to increase the efficiency of underground gas drainage and to maintain growing intensity of gaseous coal seam development

ANALYSIS OF STATISTICAL STUDY OF ELECTRIC LOADS

The paper discusses the issues of determining the statistical characteristics and coefficients in the modes of power consumption. The basic calculations of the statistical coefficients of power consumption and characteristics of the electrical load are presented. The presented results can be used for calculations and improvement of power consumption modes; optimization calculations.В работе рассматриваются вопросы определения статистических характеристики и коэффициентов в режимах электропотребления. Приведены основные расчеты статистических коэффициентов электропотребления и характеристик электрической нагрузки. Представленные результаты могут быть использованы для расчетов и улучшения режимов электропотребления; проведения оптимизационных расчетов

Immissionen in der Landwirtschaft : Eine rechtliche Analyse im Lichte des oö Bau- und Raumordnungsrechts, sowie des zivilen Nachbarrechts

Als Nachbar eines landwirtschaftlichen Betriebes ist man neben Lärm, Erschütterungen und Staubimmissionen auch unangenehmen Geruchsimmissionen ausgesetzt. Sowohl das oberösterreichische Bau- und Raumordnungsrecht, als auch das zivile Nachbarrecht geben dem belästigten Nachbarn unter gewissen Voraussetzungen eine Handhabe gegen Geruchsimmissionen. Die vorliegende Diplomarbeit bietet einen wissenschaftlichen Einblick in die wichtigsten gesetzlichen Abwehrmöglichkeiten gegen landwirtschaftliche Geruchsimmissionen und behandelt deren Effektivität und Eignung.eingereicht von Christina GabaraevUniversität Linz, Diplomarbeit, 2019(VLID)355718

Heavy liquid metal cooled fast reactors: peculiarities and development status of the major projects

Fast reactors with heavy liquid metal coolant (lead or eutectic bismuth-lead alloy) are one of the most advanced technologies capable to address the accumulated world nuclear energy issues. This innovative power technology is being developed in Russia, the USA, China and the European Union. Russia is the leader since it has focused on this topic for a number of decades. First concrete started to be poured in June 2021 to form the foundation of the Russian BREST-OD-300 lead cooled reactor scheduled to be started up in 2026. Attention is also given to the development status of the Chinese CLEAR reactor series. A large scope of R&D has been undertaken, and large-scale nonnuclear experimental facilities are under construction. International Euro-US consortiums for the development of the ALFRED, PLFR and MYRRHA reactors do not expect any unsolvable technical issues either and are currently formulating requirements to the test facilities and candidate materials and technologies required for further activities

Pillar dimensions optimization in room-and-pillar mining in underground mines

Research objective is to optimize pillar dimensions in room-and-pillar mining in underground mines. Methods of research include analyzing theory and practice in this field and carrying out engineering forecast for the prospects of room-and-pillar mining. Results. The article explains the urgency of pillar dimensions optimization aimed at ensuring personnel, equipment and subsoil safety. The article shows the role of mining-geological and technological factors that weaken the rock mass and introduces the resulting coefficient of pillar design diameter increase for a pillar within the stress-strained rock mass system. Formulas are presented calculating safe pillar increase parameters to compensate for its weakening caused by the manifestation of natural and man-induced factors of various origins. The order of weakening coefficients quantitative values is determined based on specific mining conditions and established regularities, including those depending on probabilistic indices. Weakening coefficients have been characterized considering the data about the factors behaviour. The dependence between the pillar strength and the pillar base strength has been extended. The role of stresses crucial for the pillars is revealed, and an algorithm for their forecast based on probable mathematical models is recommended. Conclusions. Based on this study data, pillar dimensions in room-and-pillar mining in underground mines can be optimized. It is recommended to use the research results when designing an ore extraction technology and adjusting the development parameters</jats:p

The technology of mining tungsten-molybdenum ore of Slepaya Zalezh at Tyrnyauz deposit

Introduction. The article considers the issues of base ore effective mining at the Tyrnyauz tungsten-molybdenum deposit with different methods for filling man-made voids. The objective is to substantiate the reduction in expenditure on the ore-hosting rock mass state control by using tailings to prepare the backfill blends Methods of research. The complex of studies includes the study of engineering and geological conditions of development, the study of the properties of hardening mixture components, the theoretical justification of rock mass stability control methods, and the proposed solutions evaluation. Laboratory studies are carried out on samples made of equivalent and optically active materials. Physical and mechanical properties of rocks and blends are determined using the accepted methods, results are processed by mathematical statistics methods. Results. Ore-hosting rock mass states are analyzed when using a development system with open or filled unbound material. The ore mining technologies type designs by the criterion of rock mass stress control is proposed. The results of modeling the methods of fields development are presented, with and without voids filling, as well as a mathematical model construction and calculation in Maple. The optimal parameters of lost reserves dredging are calculated. The equivalence of qualitative indicators of losses and other field development efficiency indicators has been established. The results of modeling various technologies with different degrees of void filling are given. It is shown that ore loss and dilution mitigation, when optimizing the rock mass state control, compensates for the costs of hardening mixtures. Conclusions and scope of results. Field development without void filling increases losses and dilution to the limit of economic feasibility. There are equivalent ratios between ore quality indicators and other technology indicators, which are the basis for improving the indicators of the lost ore reserves extraction. The obtained results may be in demand when modernizing technologies for the development of solid metal-containing mineral raw materials.</jats:p