The use of stage-wise schemes in the development of deep quarries is one of the ways to increase the economic efficiency of mining a deposit and determining the optimal stage parameters remains an urgent task. Such parameters are stage depth, bench height, block length, etc. However, there is a wide range of values for these parameters. Therefore, to select the optimal values and evaluate the effectiveness of design solutions, it is advisable to use the net present value, which is an international notion. As a result of the analysis of data on deposits, a large number of variable indicators can be identified that presumably affect the efficiency of mining. The article proposes to divide all parameters of the quarry mining into two types: mine engineering and economic. The importance of each of them is determined by the measure of influence on the net present value. Thus, to assess the measure of influence of mining indicators, the average values of each of them are taken, and as a result of the alternating change of one parameter under study, the measure of its influence on the discounted income received is estimated. The results of the analysis of relevant factors, their evaluation and comparative analysis are important indicators that significantly affect the design decisions made and the effectiveness of the investment project.
To study stochastic mining technical systems of opencast mines, where parallel to clearly defined values random and indefinite factors operate, probabilistic and statistical techniques are mostly used nowadays. Formally, the task of producing a design solution may, under the conditions of indeterminacy be transformed into an equivalent deterministic problem formulated for a risky situation. Uncertainty in the initial mining, geological and technical-economic information available during the design stage may result in changing the principal output characteristics of the opencast mine and undermine its operational efficiency during its exploitation. Lowering the possible economic losses is then possible via designing a stable technological system. To minimize the degree of indeterminacy one first of all needs to identify the area of potential risk, define the probability of its emergence and assess its potential consequences. In case such consequences may be precluded, a clearer more complete understanding of the problem would promote a better thought through reaction to potential risk in the course of implementing design solutions.
The article describes sensitivity analysis, aimed at variables dependence detection: to what extent open cast mine ultimate efficiency or performance will be affected when one of the key input variables is changed. The stronger the dependence effect, the higher the project implementation risk. The sensitivity analysis objective is demonstrated – principle factors identification – critical variables, capable of having a serious influence on the project implementation results, and impact verification of progressive (single) factorial changes. Sensitivity analysis in its content is a single-factor analysis. Output, as a basic performance indicator of an open cast mine, characterizes mine development intensity and is determined by mining-engineering and economic factors. It is proved that the impact degree from various parameters on the open cast mine output is characterized by elasticity ratio. The project indicators sensitivity analysis, which was carried out, allowed to establish the impact degree that various parameters have on the open cast mine output, which takes place in a high-angle ore deposit, characterized by elasticity ratio.
The balancing stripping ratio and ore production methods include simulation in order to reduce the prestripping waste and maintain a suitable space between each bench. The reliability analysis method of mining technological system in mine design is discussed in this paper. The probabilistic approach used here takes into consideration the uncertainty associated with estimation of most economic, mining and geological variables. This paper concerns the rational distribution of reserves which can be mined and waste advancing down the open cast site at steep pitch deposit.
The opencast geological conditions analysis and the mining units formation in ore losses and dilution determining is given in dynamic type. The optimum height of immixed rocks triangle on minimum economic damage from losses and dilution criterion is determined. Minimum damage of an enterprise from losses and dilution of one ton of ore that provides minimum producing cost of ore mining is accepted as a criterion of optimum correlation of technological standards of rate of contact areas and standards of losses and dilution of ore.
Horizontal or gently dipping (less than 10 ), mineral deposits, to which the majority of sedimentary deposits, such as oil shale, coal, peat, clay, limestone etc. belongs to, with relatively thick sediment overburden advisable to practice using transtoptless overburden removal technology, that is using a powerful stripping equipment – draglines. The main advantage of this technology is the placement of overburden directly into quarries goaf, significantly reducing the rented for the waste dumps disposing areas, and reduce the costs of mining-reclamation works.
Coal mining can result in a number of adverse effects on the environment. Open cast coal mines leaves areas of land that are no longer usable and leaves a scarred landscape with no scenic value. Rehabilitation can mitigate some of these concerns. Mine tailing dumps produce acid mine drainage which can seep into waterways and aquifers with consequences on ecological and human health. Subsidence of land surfaces due to collapse of mine tunnels can also occur. During the mining operation methane, a potent greenhouse gas and a constituent of fire damp, can be released. Wherever it occurs in the world, surface mining of coal completely eliminates existing vegetation, destroys the genetic soil profile, displaces or destroys wildlife and habitat, degrades air quality, alters current land uses, and to some extent permanently changes the general topography of the area mined.
The equation to calculate economic damage from losses and dilution of minerals is given in dynamic type. The optimum height of immixed rocks triangle on minimum economic damage from losses and dilution criterion is determined. The equation for determination of the optimum safety berm width when forming the final edge of an open pit is presented.
Converting disturbed as a result of industrial activity land in a state in-suitable for use in the national economy, to prevent their negative impacts on the surrounding landscape complexes, the protection of these complexes, optimization of the combination of man-made and natural landscapes is achieved revegetation. Recultivation of the tailings left behind after work Dzhidinsky mining treatment complex will ensure reduction of negative impacts on the environment and human health.
The mining-transport equipment in technological schemes with application of the mobile crushing equipment represents difficult mining system with consecutive and parallel connection of separate technological elements. Reliability of system is defined on the basis of reliability of its components.
On an international level, economic assessment of deposits is done through dynamic methods which take the time factor for investments and returns, i.e. the time value of money, into account and are based on compound interest formulae. The economic benefit of mining enterprise and investment's attractiveness indicated by net present value and internal return rate in dynamic investment forecast model. This study will only deal with simple cash flow calculations a geologist or mining engineer will have to make in the prefeasibility stage of a project in order to establish whether an exploration project worth pursuing.
The problem of accuracy and reliability of design decisions is a characteristic feature of the present stage in development of all material production spheres, including the mining industry. A whole range of unresolved problems still exists in enhancing reliability of open-pits designing. A lot of research publications are investigating interrelations of the accuracy and uncertainty categories with reference to specific conditions in order to solve practical problems. Scientific research in decision-making techniques in conditions of uncertainty and risk, in development of heuristic approaches, methods of stochastic modelling and programming are of utmost interest in terms of open-pit designing.
This paper first of all examines the notion of an equilibrium price for a mineral cоmmodity market. It draws the conclusion that microeconomic theory alone cannot define such a price. It then recapitulates on the reasons for price fluctuations and shows that one can at least identify a floor price and a ceiling price when it proves impossible to identify an equilibrium price. To conclude, it proposes a method for price forecasting, based on a prior analysis of the relevant industrial structure involved.
Производительность карьера должна определяться с учетом спроса на рынке минерального сырья. Продолжительность отработки месторождения и непосредственно связанная с ней производительность карьера влияют на конкурентоспособность предприятия, на результаты обоснования инвестиций в строительство карьера, так как от этих показателей зависит себестоимость добычи. Спрос характеризует взаимосвязь между производительностью карьеров и ценой, и если спрос реагирует на изменение цены значительно, то он характеризуется как эластичный. Для определения оптимальной производительности карьеров с учетом спроса можно применить принцип предельности: для установления оптимума необходимо сравнить дополнительные издержки, возникающие при увеличении производительности с ценностью добываемой при этом дополнительно руды. Максимум чистой текущей стоимости руды, реализованной за весь срок отработки месторождения, достигается при равенстве относительного увеличения себестоимости и относительного увеличения дохода.
Проекты карьеров, выполненные традиционным способом, без компьютерного моделирования, создают при эксплуатации риск выемки завышенных объемов вскрыши и потерь части балансовых запасов за пределами конечного контура отработки. Без блочных моделей залежи вариации содержания в руде при добыче зачастую невозможно сгладить усреднительными складами. В мире применяется около десятка программных систем для эффективного решения задач проектирования карьеров. Их функциональные возможности схожи, но сам по себе выбор одного из нескольких возможных вариантов программ для автоматизации горно-геометрических расчетов и оптимизации управления добычей требует углубленного анализа. Так , в В ИЗЕКСе, русскоязычной версии Micromine Visual Explorer, использованы нетрадиционные термины, не включены необходимые параметры площадок примыкания и т.п.
