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By V. Ogarlaci

Over 90% of the Romania's lignite reserve is located in the region of Oltenia, which is why this area is given special attention in the country's coal resources. Because the lignite deposit of Oltenia is comprised of 1-8 exploitable coal layers, their capitalizing calls for urgent arrangements to ensure rational exploitation under conditions of total safety, minimum losses and efficiency. The technology used the coal pits of North-Western Oltenia is the technology of excavation, transport and dumping in a continuous flow by using the complexes of excavation, transport and high-capacity dumping. The theme of this paper is of particular importance because the rhythmic operation in complete safety, is necessary both for sizing and keeping within the bounds of acceptable values, throughout the process of excavation of the geometric elements of the coal faces, marked by: the height of benches, slope angle and width of berms. Geometric dimensions of the benches of the open pits, the height of benches, slope angle and width of berms shall be calculated and shall be based on: the massif structure that forms the benches; physical-mechanical characteristics of rocks from the bench; working conditions, characterized mainly by mining and extraction methods applied; functional parameters of the mechanical equipment used to perform various operations on the coal face etc. For this study it was necessary a broad field for task tracking, measurement, research and design elements of the coal face, for land survey and a desk activity by: processing of topographic data, laboratory analyses on physical and mechanical properties of rocks and numerous specialized studies. In the final part, we bring some contributions to elucidating the issues of special importance for the lignite coal pits of Oltenia, coming up with data, graphics, formulas, solutions and concrete dimensioning of coal faces in terms of using technology in a continuous flow.

Aug 1, 2013

By David Forrester

"At the 95th CIM Annual General Meeting in Calgary, 1993, a paper entitled “Progress on Futuristic Mining Technologies” was presented(Matthews and Sarin), in which they outlined the goal of continuous excavation of hard rock and some of the technologies being developed to achieve it. The subject continues to be featured in periodic reviews and articles in the literature, (Gertsch, 1994; E&MJ, 1995). Matthews and Sarin note the considerable success of the development and application of continuous mining technologies in the soft rock under-ground mining industry, especially those in coal and potash, with major benefit to overall production, productivity and economic viability. It is the belief that similar achievements can be realised in the underground hard rock mining which continues to drive the development of hardrock continuous mining technology.This overview has been prepared specifically for this issue of the CIM Bulletin. It attempts to tie together current advancements in continuous mining in soft rock (where remote control and automation are already well established) with the background and status of development in hard rock continuous mining. Following a brief review of key factors and machine types, soft rock aspects are discussed, then a more detailed review is given of hard rock technology, with particular reference to Canada’s HRDK Mining Research Ltd. and their key role.The mining industry has long been at the forefront of technology development, for example, the application of the early steam engine to reach reserves at greater depth for dewatering mines in the industrial revolution. By necessity, the individual characteristics of seams and orebodies dictate the mining method, continually presenting mining engineers with new challenges. One of these is the extraction process itself and the goal of replacement of the drill-blast-muck cycle by continuous excavation. Very soft rocks have always been mineable using some form of cutting, even with primative tools. However, as the challenge has been taken up, technologies have evolved to steadily increase the hardness of rock that can be mechanically excavated. It may surprise some readers that at least three machines have successfully cut and loaded rock with an unconfined compressive strength (UCS) of 250 Mpa to 300 MPa (36 000 to 43 500 psi) in field trials (Table 1)."

Jan 1, 1996

By A. -M. Cadieux

During the geological synthesis of the Réservoir Pipmuacan area (NTS 22E) by the Ministère des Ressources naturelles (Québec), several ilmenite-apatite occurrences, some well-known and some recently discovered, have been examined. These occurrences are hosted in the Lac-Saint-Jean and Labrieville AMCG anorthositic suites. The Lac-Saint-Jean Anorthositic Suite (1160-1140 Ma), composed of multiple intrusions covering an extensive surface area, is characterized by labradorite plagioclase. The Labrieville Anorthositic Suite (1010-1008 Ma) is characterized by andesine plagioclase. It was previously known as the Labrieville Anorthosite, which was composed of a small isolated pluton located east of the Lac-Saint-Jean Anorthositic Suite. However, new geochronological data and field observations indicate that the Labrieville Anorthositic Suite in fact includes several intrusive bodies, namely the La Hache Monzonite and the Mattawa Anorthosite. A series of major structures (Saint-Fulgence, Pipmuacan, and Chute-des-Passes deformation zones) and their conjugate faults played an important role in the emplacement of the Lac-Saint-Jean Anorthositic Suite. The Saint-Fulgence deformation zone appears to have been involved in the emplacement of the Labrieville Anorthositic Suite. Oxide mineralizations are abundant in both anorthositic suites. Ilmenite, magnetite (± titaniferous), and apatite assemblages are found mostly in the labradorite-type anorthosites, while hemo-ilmenite, magnetite and apatite assemblages are associated only with the andesine-type anorthosites. Field works has revealed ilmenite-apatite mineralizations in a variety of settings, with grades reaching 48% TiO2, 16.2% P2O5, and 71.7% Fe2O3 (tot). Numerous oxide-bearing gabbronorites, often accompanied by or located near massive apatite-oxide accumulations (nelsonites), were discovered. Among these oxide-rich zones, breccia zones with anorthosite enclaves in an oxide matrix (ilmenite-magnetiteapatite) have been observed. Locally, ilmenite-apatite mineralization occurs as cumulate concentrations in ultramafic rocks. Evidence has been observed for immiscible magmas, for magmas differentiated from a mangerite or jotunite parent, and even for late magmas differentiated from the anorthosite magma itself (apatite-bearing anorthosite). Finally, the northern part of the Lac-Saint-Jean Anorthositic Suite hosts sulfide and vanadium mineralizations associated with ilmenite-apatite enriched zones, with grades reaching 1.48% Cu, 1.22% Ni, 1.6% Cr2O5, 0.25% Co, and 0.52% V2O5.

May 1, 2003

By S. Shokri

The increasing size and complexity of mega construction projects result in having several geographically distributed stakeholders, collaborating with each other to successfully deliver the project. Electronic Product and Process Management Systems (EPPMS) are recently emerging to facilitate the collaboration between stakeholders, reduce the surprises and issues, and improve the project productivity. These are commercially successful but evolving systems. An important component of EPPMS is the Interface Management System, which aims at formalizing and automating the communication channels between stakeholders. An interface is generally considered the link between construction elements, phases, or stakeholders. An interface Management System (IMS) involves five iterative steps: (1) Interface Identification, (2) Interface Documentation, (3) Interface Transferring, (4) Interface Communication, and (5) Interface Closing. A fundamental part of step 2 is recognizing different roles in dealing with interfaces. Each stakeholder is assigned a different role, such as responsible, accountable, consulted, and informed. In a mega project, several thousands of interfaces exist with complex relationships between stakeholders. Therefore, identifying stakeholders with higher responsible roles has been requested as useful information to the project owner in dealing with some of the project risks. After the interfaces are determined, and the responsibilities are allocated, the critical stakeholders are identified using the centrality concept in Social Network Analysis. The critical stakeholders can be determined at the highest level, considering all types of interfaces, as well as for each specific type or discipline-related interfaces. The proposed methodology is applied on a hypothetical offshore project with over 500 interfaces. In fact, this project is a simplified representation of a real scale Liquid Natural Gas project. In order to reduce the complexity of calculations and clarity of explanations, the simplified case study is used. By implementing IMS in mega projects, different parties not only formalize the communication between each other, but also gain better visibility concerning their roles and responsibilities. In addition, the owner benefits from analysing the complex relationships between stakeholders to further identify critical ones, along with other criteria like package cost, stakeholders? experiences, etc.

Aug 1, 2013

By M. Aljarrah

The phase equilibria in the Mg-Al-Ca system was investigated experimentally by differential scanning calorimetry (DSC) and X-ray diffraction (XRD) techniques similarly the Mg-Al-Sr system has been studied using DSC and XRD as well as scanning electron microscopy/energy dispersive spectrometer (SEM/EDS) and quantitative electron probe micro-analysis (EPMA). A new ternary solid solution MgxAl4,xSr was confirmed in Mg-Al-Sr system, which is a substitutional solid solution of Mg atoms in Al4Sr. Maximum solubilities of 21.3 at.% Al in Mg17Sr2 and 11.4 at.% Al in Mg were observed. It was also noticed that Mg38Sr9 dissolved 12.5 at.% Al. In the Mg-Al-Ca ternary system, one of the invariant transformations predicted by thermodynamic modeling was verified experimentally and found to occur at 512°C with composition close to 10.8 at.% Ca, 79.5 at.% Mg and 9.7 at.% Al. A ternary solid solution (Mg,Al)2Ca was confirmed where large solid solubility of Al in Mg2Ca was observed.

Jan 1, 2006

By T. Boiselle, C. Gielen, P. Henry, J. M. Bier

"Hydrometal is specialized in the production of zinc sulphate from complex secondary raw materials. Electric Arc Furnace (EAF) dust is one of the more interesting potential sources to produce zinc sulphate. In order to minimize waste quantities generated from EAF dust treatment, our R&D team has developed and patented a new process to recover the Fe contained in the dust as iron oxide product to be used and sold into the pigment market. The process is based on a specific reductive leaching step of the zinc ferrite contained in EAF dust, followed by a purification step to remove impurities (Ni, Cr, Cu...) and finally the controlled precipitation of the iron oxide. The aim of the iron precipitation step is to obtain the right shape and length of crystals in order to guarantee the right color and tinting strength of the pigment. The innovative aspects of the process results in the controlled oxidation of the iron to get the right crystal size and good purity material. The iron product can be valorized as red or yellow pigment often produced by the Penniman-Zoph process.INTRODUCTION A Few Words about HYDROMETAL Hydrometal SA (Engis, Belgium) is a subsidiary of Jean Goldschmidt International SA (JGI) in Brussels. JGI is mainly involved in metal trading activities (Goldschmidt, 1995). In 1985, JGI acquired the leaching circuit of a Belgian electrolytic zinc producer located in Engis, a few kilometers south of Liège, near the river Meuse and it was decided to name this plant: SA HYDROMETAL. Hydrometal is well connected by water, rail and road from its central location in the industrial region of Liege, in the heart of Europe. The company received in 1997 an additional license to process and recycle toxic and hazardous waste. Figure 1 shows a picture of the plant."

Jan 1, 2016

By Leopoldo Gutierrez, Sergio Castro, Lina M. Uribe, Janusz S. Laskowski

"The effect of sulfite and metabisulfite ions on the amyl xanthate flotation of copper-activated pyrite, in distilled water and seawater, has been studied by micro-flotation tests and redox potential measurements. The activation of pyrite was carried out varying copper ions concentration. It was found that in the presence of copper ions in solution, sulfite and metabisulfite are able to depress copper-activated pyrite at neutral or slightly acid pH. After the addition of sulfite or metabisulfite ions the resulting pH is more acidic with metabisulfite ions. A significant increase of the redox potential of the solution was observed as copper ions concentration increased. Then, the initial reducing conditions brought about by sulfite and metabisulfite ions, change abruptly to oxidizing conditions in the presence of copper ions. Under these oxidizing conditions, the metabisulfite showed to be an effective depressant for pyrite mainly in seawater. However, sulfite was a pyrite depressant in both distilled water and seawater. Based on these results, the pyrite depression by sulfoxy-depressants during the flotation of Cu/Mo ores in distilled water and seawater is discussed.INTRODUCTIONDepression of pyrite by sulfoxy-depressants (sulfite and metabisulfite) in the presence of copper ions is an important issue. This is particularly true when pyrite depression in the flotation of Cu/Mo sulfide ores is carried out in seawater. The use of lime in seawater must be avoided because the formation of magnesium hydroxy-complexes and precipitating magnesium hydroxide strongly depresses molybdenite flotation (Castro et al., 2014). In order to solve this problem, one large plant in Chile uses sodium metabisulfite (MBS) instead of lime to depress pyrite in seawater. In plant practice, this also improves molybdenite flotation since with the use of MBS the pyrite depression is carried out at pH 6-7, instead the pH 11-12 usually employed with lime.From a general point of view, pyrite exhibits some natural floatability over acidic pH ranges and may be partially floated without thiol collectors (a coating of sulfur/polysulfides has been claimed). Therefore, pyrite flotation with xanthates is usually high in the acidic pH region, but decreases greatly at alkaline pH (Leppinen, 1990; Fornasiero and Ralston, 1992; Zhang et al., 1997)."

Jan 1, 2016

By M. Y. Williams

Introduction During the economic investigation of Pacific Great Eastern Railway subsidy lands, the P.G.E. Survey of Resources made a geological and mineral survey of a large part of the valley of the Peace river as included in the Province of British Columbia. The immediate valley of the Peace river was surveyed from the mountains to the Alberta boundary; the valley of the Pine river was surveyed throughout; and the Dominion block, 70 miles square and lying astride the Peace river, westward from the Alberta boundary, was very carefully surveyed. The writer was in general charge of the field work, and spent half the field season of 1929 and the field season of 1930 in the region . J. B. Bocock, however, did the major part of the work, spending two seasons, 1929 and 1930, in the area. General Conclusions The rock formations within the area discussed are all sedimentary and range in age from pre-Cambrian to recent. As might be expected, the minerals are in the main non-metallic, coal being by far the most important. Favourable conditions exist for natural gas occurrence, and suitable structures for petroleum concentration occur, although the high carbon ratio of the coals sheds considerable doubt upon the actual occurrence of oil in the area. Materials of minor interest are ochre, calcareous tufa, marl, limonite, gravel, and building stone.

Jan 1, 1934

By J. Karonen, M. Tiihonen, J. Guentner, L. Haavanlammi, Outotec GmbH, E. Kolehmainen

"Rare earth elements have obtained significant attention during the last few years due to predicted increase in their demand. Several projects worldwide are at pre-feasibility or feasibility stage aiming to commence production. Deposits of rare earth elements are typically complex and multi-metallic of nature. This means that production processes are often also complex and therefore, various metallurgical unit processes are needed. Outotec’s equipment and technology portfolio is very comprehensive and includes hydrometallurgical and pyrometallurgical apparatus and processes applicable to the efficient exploitation of rare earth deposits. Outotec has gained useful experience relevant to the processing of rare earths through several assignments including those for Alkane Resources Ltd. (Dubbo Zirconia Project), Greenland Minerals and Energy Ltd (Kvanefjeld Project), Frontier Rare Earths Limited (Zandkopsdrift project), Tantalus Rare Earths AG (Madagascar), Quest Rare Metals (Strange Lake project) and Orbite Aluminae Inc. (HPA project). The hydrometallurgical test work of two process flowsheets is presented in the paper. A roasting or acid baking step is common to several proposed rare earth projects. In the past, rotary kilns have been used, but Outotec has developed a new process concept to handle the rare earth material in fluid bed reactors. The basis for this development is long experience in fluid bed technology of Outotec in Germany. One advantage of fluid bed roasting is the higher throughput per unit. In combination with the roasting and baking, Outotec offers the gas cleaning and acid plant and provides a complete and closed concept.INTRODUCTIONRecovery of rare earth elements (REE) has obtained significant attention during recent years. It has been estimated that their demand will be boosted because of their need in many technology areas. REE can be utilized in magnets, batteries, displays, catalysts, optical devices etc. (Jordens, Cheng, & Waters, 2013; Zhang & Edwards, 2013). The production of REE is focused in China, which means that production outside of China is very scarce. However, there are multiple active development projects worldwide working towards production of REE containing products outside of China (Chen, 2011)."

Jan 1, 2016

By Ling Wu

The development of pyrometallurgical technologies has been focused on new smelting reactors, but the proposal for new converting reactors has been substantially lower. Up to today about 80% of copper matte is treated by the traditional P-S converters which have the weakness of pollutant fugitive emissions. Therefore, the continuously converting processes for treating molten matte have been studied and developed. In July 2017 the "oxygen-rich side blowing smelting + multi-lances top converting & fire refining" continuous copper treating process was commissioned. This process was designed by ENFI and YanTai GuoRun Copper Smelter. In this process, oxygen rich side blow technology is adopted for smelting, which is a new type of side blowing smelting furnace to produce high-grade copper matte. The converting adopts the horizontal multi-lances top-blowing continuously converting process, which eliminates the transportation of molten melt and the SO2 fugitive emission. The intermediate products of this process, copper matte and blister copper is fed into the furnaces respectively through launders. This new process is more advanced, more reliable and more environmentally friendly. Until now, this process in the GuoRun copper smelter is operating smoothly. An increasing number of projects which use this process are under design and construction in China. INTRODUCTION At present, there are many advanced smelting technologies for copper concentrate, such as oxygen bottom blowing smelting, flash smelting, top lance smelting (including ISA and Ausmelt furnaces smelting), side blowing smelting, Mitsubishi smelting, etc. At the same time, there are many copper matte converting technologies such as oxygen bottom blowing continuous converting, flash converting, Ausmelt top lance converting, horizontal multi-lances top blowing converting, Mitsubishi converting, P-S converter converting, etc. The final blister copper fire refining technology mostly adopts rotary anode furnace. Therefore, in the process of processing and extracting the copper from concentrate to produce anodes, there are dozens of technology combinations. Among them, the non-continuous converting technologies for molten or cold matte are often adopted in the converting process. The traditional P-S converting technology had been utilized for over one hundred years, with a mature, reliable and simple operation, also has advantages in the secondary scrap smelting of a wide range of quality. However, due to its batch operation, frequent roll in and out, poor sealing, considerable air infiltration, needs for ladles for molten phases transportation and other characteristics, the technology has a serious pollution problem due to fugitive SO2. At the same time, in the cold matte converting technology, the molten matte needs to be cooled and then processed. The sensible heat of the molten matte cannot be recovered, and the preparation process is needed in the process. Therefore, both energy consumption and investment are relatively higher.

Jan 1, 2019

By B. S. W. Buffam

"The property of Moneta Porcupine Mines, Limited, consists of a group of eight claims in Tisdale township, Ontario. It includes part of the townsite of the town of Timmins, and adjoins the west boundaries of the Hollin_ger Consolidated and Mace properties. The Moneta property was first staked in 1909, about a year after the first discovery of gold in the Porcupine camp. In 1910 the Moneta Company was incorporated and some preliminary exploratory work performed by Nova Scotia Mines of Cobalt. In 1912 English interests advanced $90,000 for diamond drilling and underground work. One drill hole gave high assays, but apparently the records were poorly kept or the cores were interchanged. As a consequence, when underground exploration was undertaken in 1923 it was directed south rather than west and no ore was found . In 1924 about 5,000 feet of diamond drilling was done in the southern part of the property, but without intersecting ore.In 1931 W. E. Segsworth assumed the direction of the property. Diamond drilling commenced on August 18, 1936. The first hole intersected 9.9 feet of ore averaging 1.23 oz. gold a ton. Underground work was started early in 1937. A mill was erected in the autumn and the first gold brick was poured January 29, 1938.The Moneta mill began operation on January 2, 1938, and the following table gives a summary of the production to June 30, 1943, when the mill was closed."

Jan 1, 1954

By Andrew Thrift

Overview ? Problem ? Research question ? Literature review ? Methodology ? Results ? Discussion and recommendations ? New developments Problem ? Increasingly higher expectations ? Inadequate consultation leads to conflict rather than collaboration ? Consultation practice is often weak on decision-making ? Influence of consultation on planning is Unclear Research question ? Are Structured Decision Processes (based on decision analysis) an effective methodology for involving stakeholders in consultative decisionmaking in the mining industry?

May 1, 2006

By T. G. Joseph

The strain softening relationship developed in part 1 is now applied to coal. Having determined the post-failure stress-strain curve for coal specimens, this information can then be used in a finite element program, such as Phase 2, to examine the post failure characteristics of coal pillars. Using example data, the strength of coal pillars of different width/height ratios are estimated and compared with well-known empirical pillar size-strength relationships. In addition, the post-failure stress-strain behaviour of a coal pillar is compared with an empirical relationship reported in the literature.

May 1, 2002

By Richard Hurteau

Design and validation of an integrated guidance system for articulated ground vehicles is investigated. The development of an autonomous industrial vehicle must take into the account the specific geometry of these vehicles; they can be composed of a tractor with 1 or 2 trailers or of articulated type like LHD. Moreover the tractor-trailers type vehicles can have on-axle hitch configuration or positive/negative off axle configuration. The path-tracking of a tractor-trailer vehicle in restricted space is presented and discussed in this paper. Recent results obtained in simulation and validated by experimentation are also presented. These studies can lead to better ways of maneuvering an articulated vehicle in a restricted space or automatically executing of docking and parking maneuvers

May 1, 2002

By F. Rosenblum, P. Spira

A laboratory test has been developed for assessing the patential hazard from self-heating of sulphides. The technique consists in measuring the rate of self-heating, from near ambient temperature, of a 1-kg sample in an insulated chamber controlled at standard atmospheric conditions. The rate of oxygen consumption is monitored simultaneously. The paper describes the apparatus and test procedure, and reports data on various ores and mill products. Tailings known to have caused problems underground when used as backfill have shown heating rates of over 3°C/h. A preliminary hazard rating guide for backfill based on the known behaviour of several sulphide materials is presented.

Jan 1, 1981

By Takashi Nakamura, Atsushi Iizuka, Yong Fan, Etsuro Shibata

Magnetic separation of precipitated magnetite as iron resources in copper slag is one of the potential effective ways to recycle the slag. It is preferable to convert molten fayalite slag after copper smelting process to magnetite slag via oxidation. With a TTT (Time-Temperature-Transformation) diagram, the crystal composition of the slag obtained after air isothermal oxidation could be estimated through a designed cooling path. The crystallization behaviors concerned with molten oxidation was studied for better understanding of the trade-off relationship between magnetite and hematite during molten heat treatment. Moreover, a brief consideration was implemented of the reaction mechanism.

Jan 1, 2014

By A. Fakhimi

The effect of porosity on mechanical behavior of rock has been studied in the past using both experimental and numerical techniques. One important aspect of this study that has not received much attention is the role of void size and distribution on the mechanical behavior of rock. In this study, the CA2 computer program that is a hybrid discrete-finite element program for two-dimensional simulation of geomaterials is used. Numerical specimens with different macro-void sizes are loaded uniaxially. The Young?s modulus, Poisson?s ratio, uniaxial strength and crack initiation stress are studied. The numerical results are compared with the database of experimental tests on Plaster of Paris specimens containing Styrofoam spheres with different void sizes and porosities. It is shown that the macro void spatial distribution is partly responsible for the scatter of the experimental data. It is also shown that not-only the porosity but also the pore size can affect the deformability, crack initiation stress and rock strength.

May 1, 2009

By R. D. Brown

"AbstractOver the past five years, tax rates in the Canadian mining industry have skyrocketed upward across Canada, as both federal and provincial governments have sought to increase their share of mining revenues.However, the past few years have not only brought high tax rates to the industry, but also a number of important new federal and provincial tax incentives.In large part, these incentives ~ special credits or reduction in tax for carrying out specific exploration, processing or other activities - have helped to moderate the adverse effects of the higher tax rates and have provided inducements for exploration and processing activities which might not otherwise have been undertaken.However, the effectiveness of certain of these incentives can be questioned: our over-all tax structure now consists in large part of punitively high marginal rates with some extraordinarily generous but capricious tax reductions for specific activities and may not be in the best long-term interest of either the industry or the nation.A rational tax structure, with moderate and stable tax rates, together with reasonable incentives confined to activities specifically requiring them, could be a more effective spur to investment than the present tax and incentive jungleIntroductionIN THE YEARS since federal tax reform, the mining industry in Canada has faced a continued escalation in its tax burdens as federal and provincial governments have leapfrogged each other in imposing new and higher taxes on the industry. The result has been that marginal tax rates imposed on mining and processing activities throughout Canada have jumped to hitherto unparalleled levels."

Jan 1, 1977

By J. F. Shirley

"Very seldom, if ever, is a molybdenite by-product plant operated exactly the way the process design engineer visualizes it. The best thing the design engineer can do is provide a sound, basic circuit with enough room and flexibility in order that the operating staff can make the necessary modi fi cations to optimize the process. The plant, with minor modifications, should be capable of handling more than one process. This is especially true when the client is having the plant designed for a new process.The writer would like to propose the following ten ""rules-of thumb"" for designing by-product molybdenite plants where the molybdenite is floated out of a copper concentrate. The term rules-of-thumb is used, because there are probably valid reasons for not using one or more of them in a particular plant design. In fact it was 1980 before the writer was all owed to start up a plant where all of these rules were honored in the plant design. This was after 19 years of experience in the design of molybdenite by-product processes and plants. The main reasons for not following the rules are available capital, available space, and the client's experiences based on pilot plant and laboratory test results."

Jan 1, 1981

By J. C. Kurnia

Methane is recognized as one of the prime causes of underground mine disasters around the globe. A cost-effective mine ventilation system and methane control is required to ensure a safe and productive environment in an underground mine whilst keeping energy usage and operating cost at minimum. Typically methane enters a mine environment or tunnel from localized distributed sources at high initial concentration. Hence, an understanding of its dispersion from discrete sources is important to design a methane management system via effective ventilation. This study employs computational fluid dynamics to model methane dispersion in an underground tunnel which has a number of discrete sources of methane and effective ways to dilute and or disperse it. Air flow distribution within the tunnel as well as methane dispersion is simulated by solving the governing transport equations subject to appropriate boundary conditions. First, the effectiveness of ventilation duct placement is examined. Several possibilities are explored and investigated. It is found that the common configuration utilized in underground mine performs best as compared to other configurations in maintaining the concentration of methane below permissible levels. Next, a novel intermittent airflow ventilation system is proposed and evaluated via simulation with the goal of reducing the energy cost whilst maintaining methane level in the mining face below the allowable level. Parametric studies are conducted to investigate effects of various factors influencing the effectiveness and performance of this novel intermittent ventilation system. This study will provide some new ideas for designing an efficient and effective underground mine ventilation system by lowering the net average amount of air that needs to be circulated in the tunnel for a safe operation. KEYWORDS

Aug 1, 2013