Technology development of Kryvyi Rih iron ore open pits within zones stoping of underground mine working

На современном этапе отработка залежей железных руд в Кривбассе ведется в условиях как совместных открытых и подземных горных работ, так и открытой разработки месторождений в зонах, подработанных подземными выработками. Приведенные технология и новые способы и устройства погашения воронок обрушения в пределах рабочей зоны карьеров путем засыпки их рядовыми скальными породами вскрыши непосредственно с поверхности, что позволяет существенно повысить безопасность горных работ в карьере и получить значительную экономию за счет предупреждения нарушения окружающей среды внешними отвалами.На сучасному етапі відробка покладів залізних руд у Кривбасі ведеться в умовах як сумісних відкритих і підземних гірничих робіт, так і відкритої розробки родовищ у зонах, що підроблені підземними виробками. Наведені технологія й нові способи та пристрої погашення вирв обрушення у межах робочої зони кар’єрів шляхом засипки їх рядовими скельними породами розкриву безпосередньо з поверхні, що дозволяє суттєво підвищити безпеку гірничих робіт у кар’єрі й отримати значну економію за рахунок попередження порушення довкілля зовнішніми відвалами.At present iron ore in Kryvbas is mined by both a combination of open pit and underground methods and by the open pit method in zones underworked by underground mining. The suggested technology and new methods of backfilling pit craters within the pit working area with rock overburden directly from the surface that enables substantial increase of mine safety and economy due to preventing environmental damage caused by surface dumps

IMPROVING THE METHOD OF OPEN-PIT LIGNITE DEPOSITS DEVELOPMENT IN UKRAINE

Subject of the research is open-pit mining concerning a full- field industrial development of a number of lignite deposits; feasibility study has been performed for them as for the efficient environmental friendly processing of coal and associated minerals. Objective of the research is to develop both methodology and conceptual approaches to high-productive, economically viable, and environmental friendly methods for open-pit lignite mining in the context of suprasalt depressive basins. Task of the research is to analyze the current state of lignite mining in Ukraine; to characterize a new genetic Ukrainian coal type from geological and industrial viewpoint; to substantiate parameters of lignite open-pit mining on the basis of Novo-Dmytrivka mining and industrial district; to expand the capacities of lignite mining on the basis of Novo-Dmytrivka, Bantysh, Stepkivka, and Bereka deposits; to substantiate the integrated use of diverse rock masses in the context of the national economy; to use lignite in terms of its power; to produce montan wax; to apply sodium humite in the context of agriculture; to use overburden rocks for the construction of bordering dams of powerful water storages; and to develop recommendations concerning the design of Novo-Dmytrivka mining and industrial system with the integrated development of lignite and associated minerals. Methods of the research are: analytical estimation of resources of lignite deposits; geological and engineering-technical analysis; and integrated and feasibility studies of indices of mining and opening operations. Optimization of the process solutions relies upon the analysis of changes in rock mass coefficient use within the open-pit area in the context of complete land reclamation of the disturbed land and the development of new productive land instead of the littered territories. The updated research method is to determine the basic technological parameters of equipment taking into consideration significant water inflow in terms of working areas as well as the inflows effect on the output of the lignite open pit depending upon changes in the depth of mine workings. The carried out research helped study more thoroughly the geological and engineering-technical features of lignite deposits in Ukraine. Their geological structures, coal-bearing capacity and the coal grades, total reserves, and their commercial significance have been determined. Parameters of benches and working sites have been substantiated. The parameters make it possible to decrease the current volume of overburden rock mining and to transfer their maximum values to the final stage of the open pit operation. Rational systems of mining and transportation equipment for the development of the open-pit field in terms of criteria of capacity, efficiency, and power consumption have been substantiated involving different traffic flows of rock mass movement in open pits and at the surface. There were issued recommendations to design the development of Novo-Dmytrivka lignite deposit. Relying upon the analyzed deposits of north-west Donbas, it is expedient to develop the unified coal-mining complex for the processing of lignite and associated minerals to be used by plants of building materials and structures as well as chemical and metallurgical plants as the basic raw material. There has been substantiated a possibility of commercial development of a number of lignite deposits in Ukraine to develop mining and preproduction complex with coal output at the level of 9-10 min t/y and 23-24 min t/y of coaly mass as well as their processing by thermal power station which capacity is 1800-2400 MW; a plant to produce 15 thousand tons of montan wax a year; briquetting factory which capacity is 2 min t/y; and a concrete product plant to manufacture building structures with a capacity of 1 min of m2/y

AGRICULTURAL AND RECREATIONAL IMPACTS FROM SURFACE FLOW CHANGES DUE TO GOLD MINING OPERATIONS

Nevada ranks third in the world in gold production. In order to operate the massive open pit gold mines, the State of Nevada granted mining companies a temporary permit to pump groundwater from near the open pits and dispose of it. Certain instream flows have nearly doubled relative to average historical flows in recent years. Following pit closure, surface flows will likely decline from historical levels. This study measures the impacts of these changing water supplies on downstream agricultural and recreational users. We argue that the creation of temporary changes in water rights for the downstream users would likely mitigate future losses both groups are expected to experience.Resource /Energy Economics and Policy,

Simulating the effect of forces pit ventilation on ammonia emission from naturally ventilated cow houses with CFD

Atmospheric NH3, mainly originates from agricultural sources, can cause serious environmental problems related to eutrophication and soil acidification. Emissions from dairy houses are 15% of total agricultural NH3 emissions. Due to open buildings, existing abatement options are limited. Pit air separation was identified as a potentially efficacious option. In this study a model simulation of a commercial dairy cow building with slatted floor is presented. The model was solved for 12 cases, differing wind speed, direction and both air and manure temperature. For each case three solutions were obtained, which correspond a) to a building where a forced pit ventilation system is applied at capacity of 250 and 500 m-3 h-1 cow-1 and b) to a building without forced pit ventilation system. The results show that due to forced pit ventilation system, at 250 and 500 m-3 h-1 cow-1, the ventilation rate was increased 3.1% and 6.2% respectively. The contribution of the pit ventilation system to the total ammonia released from the pit during winter, ranged from 31-35%, 16-19% and 11-8%, for wind speed of 1.0, 4.0 and 8.0 m s-1 respectively. Correspondingly, during summer, the contribution of the system ranged from 44-48%, 20-21% and 12-9%. Although obvious benefits arise from a forced pit ventilation system, the main mass flow of ammonia from the pit still emitted through the building ventilation openings, especially at high wind speeds

Limnology of Four Bauxite Open-Pit Lakes

The aquatic flora and fauna and 18 physicochemical characteristics of four bauxite open-pit lakes were studied from September 1969 to August 1970. The least acid lake (pH 3.4-4.4) supported 49 different aquatic insects, plankton, and higher aquatic plants. The most acid lake (pH 2.7-3.2) supported only 26 different plants and animals. Bauxite open-pit lakes within the pH range studied appear to be as relatively unproductive as their coal strip-mine lake counterparts, with which they share physicochemical and biological characteristics. Benthic macrofaunal diversity and abundance appear to be related more closely to distribution and abundance of leaf detritus than to hydrogen-ion concentration

Exploring droplet impact near a millimetre-sized hole: comparing a closed pit with an open-ended pore

We investigate drop impact dynamics near both closed pits and open- ended pores experimentally. The resulting impact phenomena differ greatly for a pit or a pore. For the first, we observe three phenomena: a splash, a jet and an air bubble, whose appearance depends on the distance between impact location and pit. Furthermore, we found that splash velocities can reach up to seven times the impact velocity. Drop impact near a pore, however, results solely in splashing. Surprisingly, two distinct and disconnected splashing regimes occur, with a region of plain spreading in-between. For pores, splashes are less pronounced than in the pit case. We state that, for the pit case, the presence of air inside the pit plays a crucial role: it promotes splashing and allows for air bubbles to appear.Comment: 17 pages, 11 figures, 1 supplementary movie, submitted to JF

Creating Lakes from Open Pit Mines: Processes and Considerations, Emphasis on Northern Environments

Creating Lakes from Open Pit Mines: Processes and Considerations, Emphasis on Northern Environments. This document summarizes the literature of mining pit lakes (through 2007), with a particular focus on issues that are likely to be of special relevance to the creation and management of pit lakes in northern climates. Pit lakes are simply waterbodies formed by filling the open pit left upon the completion of mining operations with water. Like natural lakes, mining pit lakes display a huge diversity in each of these subject areas. However, pit lakes are young and therefore are typically in a non-equilibrium state with respect to their rate of filling, water quality, and biology. Separate sections deal with different aspects of pit lakes, including their morphometry, geology, hydrogeology, geochemistry, and biology. Depending on the type and location of the mine, there may be opportunities to enhance the recreational or ecological benefits of a given pit lake, for example, by re-landscaping and re-vegetating the shoreline, by adding engineered habitat for aquatic life, and maintaining water quality. The creation of a pit lake may be a regulatory requirement to mitigate environmental impacts from mining operations, and/or be included as part of a closure and reclamation plan. Based on published case studies of pit lakes, large-scale bio-engineering projects have had mixed success. A common consensus is that manipulation of pit lake chemistry is difficult, expensive, and takes many years to achieve remediation goals. For this reason, it is prudent to take steps throughout mine operation to reduce the likelihood of future water quality problems upon closure. Also, it makes sense to engineer the lake in such a way that it will achieve its maximal end-use potential, whether it be permanent and safe storage of mine waste, habitat for aquatic life, recreation, or water supply

ANALYSIS OF NEUTRAL MODE SELECTION CRITERIA FOR DISTRIBUTION NETWORKS OF OPEN PIT MINES

The effectiveness of any type of network neutral mode operation is determined by the appropriate technical and economic conformity of the uninterrupted power supply to consumers, the amount of capital investment and operating costs. Withal it is taken into account that all kinds of emergency disconnections of power transmission lines and substations, as a rule, lead either to the complete de- energization of consumers or to restrictions on electricity consumption