The methods of evaluation of the aerological conditions to be performed for the purpose of normalization of mining conditions are provided in the present review; the location of possible accumulations of explosive gases during the drift of the development workings are taken into account. To increase the safety of the development working regarding the gas factor, a complex evaluation of a working was developed with respect to the dynamics of methane emission and air coursing along the working which is strongly affected by the character of the leakages from the ventilation ducting. Thereby, there occurs a necessity of the enhancement of a methodical approach of calculation of ventilation of a working which consists in taking into consideration a total aerodynamic resistance of the booster fan including the local resistances of the zones of the working. An integer simulation of the gas-air flows realized on the basis of a software package FLowVision allows to evaluate a change in the methane concentration in the zones of local accumulations.
The article describes the methods for gas balance definition of working area with face zone isolation from mined-out space, that have allowed to change the air distribution in face zone and to determine the part of evolved gas from bed and marked bed.
The article describes the necessary conditions for similarity parameters choosing for aero-gas-dynamic modeling with main roof collapse and it has been made analysis of them.
The article describes the formulas for calculation of air flow characteristics, that originates from the main roof collapse and also it has been made analysis of variates, that form their parts.
A method for calculating the required amount of air for gas ventilation of the internal combustion engine of railway tunnels has been developed. This method takes into account such provisions as the direction of air movement to the direction of train movement, train speed and the number of trains simultaneously in the tunnel. Cases such as a train standing motionless with the engine running, train movement towards and against the direction of airflow, and cases of multiple trains in the tunnel are analyzed. For all variants, calculation equations of the required air quantity and recommended train speed that can ensure the concentration of pollutants in the tunnel below the MAC (maximum permissible concentration) are proposed.
The main factors determining the peculiarities of accident-free operation of railway tunnels under windless climate conditions are considered. It is shown that ice formation caused by a combination of two unfavorable phenomena: relatively low air temperature in the tunnel and high watering of the tunnel is especially dangerous. The paper presents the results of the experimental studies indicating that the gas composition of the tunnel air is determined not only by the harmful gaseous impurities emitted by the carriers but also by methane, carbon dioxide, hydrogen sulfide and radon coming from the surrounding rocks and water. The mechanism of radon impact on tunnel personnel has been studied and a large-scale description of its possible impact on air quality in the tunnel has been given. Many regions of the Russian Federation, including those where the longest railway tunnels of Russia are located: Baikalskiy and Severo-Muiskiy, can be classified as radon hazardous. Creation of rational ventilation conditions influencing not only the radiation situation but also the thermodynamic characteristics of the air should be considered as a fundamental means of achieving the required air quality in the tunnels. In order to increase the stability of ventilation conditions the possibility of using different regulating devices has been studied. The maximum influence on the air flow is exerted by the installation of a ventilation door, which allows to change the air inflow by 70% of the initial indicator. The principles of creation of the favorable temperature conditions in the railway tunnels, which is one of the effective means of ice formation prevention, have been implemented and tested on site.
Production studies using a specially developed methodology have shown that the pillar system of potash development at the Starobinsky deposit results in the release of combustible gases into the existing mine workings. The main component of these gases is methane, heavy hydrocarbons are emitted in insignificant amounts. Under normal conditions the absolute gas emission at the mine sites is insignificant. In the total gas balance of the sites, the main part (up to 98%) is gas emission from the mined-out space.
Maintaining preparatory workings in good condition is one of the conditions determining the normal development of cleaning works. ...
Устойчивость горных выработок в большой степени зависит от формы их поперечного сечения и соответствующего очертания крепи. Однако это общеизвестное положение часто не учитывается, в результате чего несущая способность крепи используется не полностью ...
Четырехшарнирная крепь представляет собой статически определимую геометрически изменяемую систему с одной степенью свободы. В наземных конструкциях геометрически изменяемые системы почти не применяются ввиду их неустойчивости. Поэтому конкретной методики их расчета строительная механика не дает ...
Tekeli lead-zinc ore deposit is a complex powerful steeply dipping lenticular deposit. The rocks of the hanging and lying sides are represented by strongly fractured, collapse-prone coal-clay shales with interlayers of dolomitized limestone and other sedimentary rocks. The ores are stronger and more stable than the host rocks and are represented by sulfides disseminated in coal-clay shales, quartzites and coal-quartz shales, as well as pyrite ores ...
The nature of manifestations of mining pressure largely depends on the size of the cross-section of mine workings. As is known, in the same mining and geological conditions, maintenance of two-track workings is much more expensive than single-track workings. In this regard, in some basins of the Soviet Union in difficult mining and geological conditions prefer to pass two smaller cross-sectional workings instead of one large one. For example, in the Moscow sub-basin panel drifts should be double-tracked according to the conditions of mining technology, because almost the entire length consists of loading points. In the reverse order of mining the mine field, it is considered more favorable to sink panel drifts as single-track drifts with subsequent expansion to double-track drifts by the time of longwall face approach. The total costs are lower than when sinking two-track drifts at once. In the latter case, the cost of maintaining the workings increases sharply ...
В текущем семилетии Тентекский и Чурубай-Нуринский угольные районы — основные районы строительства новых шахт Карагандинского бассейна. Условия поддержания горизонтальных и наклонных выработок на строящихся шахтах так же разнообразны, как и физико-механические свойства горных пород, в которых проходятся эти выработки. Поддержание откаточных выработок Тентекского района не представляет больших трудностей, так как проходка осуществляется в основном в крепких устойчивых породах. Наиболее сложны условия поддержания горных выработок шахт Караджаро-Шаханского участка Чурубай-Нуринского района, особенно на вентиляционных горизонтах. Установленная здесь крепь (деревянная сплошная, металлическая, сборная железобетонная и др.) вследствие большого всестороннего давления деформирована и должна быть заменена. Большинство выработок перекреплялось в период строительства несколько раз. Работы по перекреплению требуют больших затрат труда, времени и средств ...
В процессе бурения шахтных стволов промывочный раствор загрязняется разбуриваемой породой, что ведет к ухудшению его качества, снижению показателей бурения, а иногда к осложнениям и авариям. Для восстановления качества раствора необходимо непрерывно очищать его от разбуриваемой породы. Среди различных механизмов и устройств, применяемых для очистки промывочных растворов, наибольшее распространение получили вибрационные сита.
Очистка забоя от выбуренной породы и вынос ее на поверхность при бурении стволов и скважин является одной из основных функций, выполняемых промывочным раствором. В процессе бурения промывочный раствор загрязняется разбуренной породой и процентное содержание ее в растворе возрастает. Большое содержание выбуренной породы в промывочном растворе ухудшает его качество, влечет за собой обвалы стенок ствола (вследствие ухудшения глинизации его стенок) и представляет опасность прихвата бурового инструмента во время прекращения промывки. Кроме того, увеличение процентного содержания породы в промывочном растворе требует больших затрат энергии на промывку, увеличивает износ деталей бурового оборудования, значительно уменьшает скорость бурения.
