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By N. Kuyucak

Acid rock drainage (ARD) resulting from the natural oxidation of sulfide mineral wastes has become a major concern to the mining industry, both during the operational period and after mine closure. ARD is generally characterized by high acidity and high concentrations of dissolved metals and sulfates. If the generation of acid cannot be prevented or controlled, it must be treated to eliminate acidity and to reduce the concentration of heavy metals and suspended solids before release to the environment. Microorganisms play an important catalytic role in the generation of ARD. Several prevention, control and treatment technologies that are based on microbiological activities have been developed. The role of microorganisms and biotechnology in the generation of ARD and their role in the methods used for prevention, control and treatment are discussed in this paper. Recently developed passive and biological treatment processes that have been implemented at mine sites are emphasized in this paper. Benefits, limitations and design criteria for passive biological processes are also presented.

Jan 1, 2000

By P. R. Desam, J. D. Miller, A. Datta

The flow behavior of bubble-particle aggregates in separation tanks is important for many flotation systems, particularly for wastewater treatment. These aggregates can be considered as the dispersed phase in a continuous liquid phase of water and the flow characteristics determine the efficiency of the bubble separation process. In this work, a general methodology for the computational fluid dynamics (CFD) simulation of a bubble separation tank is described. This system is analyzed by Eulerian-Lagrangian approach. The momentum transfer from the dispersed phase to the continuous phase is quantified using the Particle-Source-In Cell (PSI-Cell) method. With CFD simulations, the effectiveness of different tank design parameters are evaluated in terms of the extent of bubble separation.

Jan 1, 2000

By John Jonkman

Two major changes occured during the last 5 years in the applications of computers. First, the cost of computer equipment decreased drastically in an era of high inflation. Second, technological breakthroughs in hardware and software have been applied successfully so that the average person can successfully utilize the computer without having to be a computer expert himself. The mining industry has recognized that computing technology has evolved to a point where it can be applied successfully to assist in improving productivity. Since equipment downtime is one of the major reasons for lost production, the Kennecott Minerals Company has developed a comprehensive maintenance information system which now assists the maintenance department in minimizing equipment downtimes. This paper discusses the primary features and functions of this system, the state-of-the-art technology that has been applied, and the benefits that resulted from using this system. Programs to support mobile equipment maintenance scheduling, which currently are under development, are reviewed and a summary of future applications is given.

Jan 1, 1982

By Mark Board

INTRODUCTION As the world's supply of near-surface metalliferous ore bodies is depleted, more emphasis must be placed upon mechanized bulk systems of underground mining. In particular, block caving is becoming increasingly important as a method of mining low to moderate grade deposits at depths of somewhat less than 1219 m (4000 ft). 00 ft). The block caving method requires that the ore body be completely undercut, thereby removing its means of support and inducing failure which progresses from the undercut to the ground surface. As the span of the under- cut increases and the weight of the overlying crushed ore body becomes greater, large stresses are induced on slusher and haulage drifts. Stability of these drifts is critical in block caving operations and often proves to be an extremely difficult task (Kendorski, 1976; McWilliams, 1975). Slusher drift maintenance can be costly, often exceeding that of the original support costs. This chapter analyzes the ground support problems of an Arizona block caving mine. The mine presently uses monolithic concrete liners as a support method. Failure of the liners occurs as the undercut approaches, thus initiating a maintenance problem which will continue until the ore body is depleted in that block or panel. To examine this problem, a simple analysis of the stresses induced by the advancing undercut was per- formed. Utilizing a design method developed by Dixon ( 1973, 1974), the calculated stresses were used to deter- mine the minimum thickness required for varying section shapes of unreinforced concrete liners. It is found that the thicknesses required for stable linings are not economic. Recently developed empirical methods of support de- sign are utilized (Barton, 1974; Bieniawski, 1973) and compared to the analytical method. A final discussion of alternative methods of support is given with recommendations for the use of passive or "yielding" support methods. LAKESHORE MINE (GENERAL GEOLOGY) The Lakeshore copper property is located in Pinal County, AZ, approximately 45 km (28 miles) south of Casa Grande. The Lakeshore deposit is a porphyry cop- per similar to others in Arizona. The ore body consists of disseminated chalcopyrite and fracture fillings in quartz monzonite porphyry (QMP), Cretaceous volcanic (KVS), Precambrian diabase, and Mescal limestone. The ore body has been divided into three distinct zones of mineralization which have been termed (South, 1972) the oxide zone, the sulfide zone, and the tactite zone. The oxide zone occurs in the upper portions of the ore body and consists primarily of leached and oxidized quartz monzonite porphyry and Cretaceous sedimentary and volcanic rocks. The sulfide zone underlies the oxide zone and includes all quartz monzonite porphyry and Cretaceous rocks which have not been oxidized. The thickness of the sulfide zone is variable and ranges from about 61 to 122 m (200 to 400 ft). The tactite zone occurs in a series of Paleozoic metasediments consisting of tactite, quartzite, diabase, hornfels, and dikes of quartz monzonite porphyry. The tactite zone is highly variable in thickness and underlies the Cretaceous volcanic and sediments throughout the mine. Together, the tactite and sulfide zones are known as the thick or tall sulfides. The greatest support stability problems occur in mining of the tactite zone and are therefore the subject of the remainder of this chapter. MINING METHOD The Lakeshore mine is a block caving mine utilizing a panel caving method. The present mine consists of two

Jan 1, 1982

By Wern-ping Chen, Jean Habimana, Jinyuan Liu, Mirza M. Rabbaig, Robert Barbour

To mitigate and control the combined sewer overflows from 17 outfalls in the City of Detroit, three outfalls in Dearborn Heights and eight outfalls in Redford Township, the Detroit Water and Sewerage Department has completed the preliminary design of a storage tunnel in 2005. In 2006, a final design has revised the alignments and the inside diameter (ID) of the tunnel. The revised tunnel system includes an 11.28-km(7-miles) 9.14-m (30-ft) ID tunnel, a 24.4-m (80-ft) ID pump station, two work shafts about 15.2-m (50-ft) ID each, and 14 drop shafts with various IDs. This paper discusses the latest development of this tunnel system.

Jan 1, 2007

By Qingming Feng, Jinhong Zhang

This study investigates the application of fly ash as a high-strength, water-resistant precast construction material through geopolymerization. The experimental results show that working conditions such as water content, sodium hydroxide (NaOH) concentration, curing temperature and curing time significantly affect the mechanical properties of the geopolymer matrix. Through optimization, compressive strength above 100 MPa was achieved, and the optimum working conditions were found to be NaOH concentration of 10 M, water content of approximately 14 to 15 percent, and curing at 90 °C in an oven for one day or at ambient condition for three weeks. Water-soaking tests show that the geopolymerization product has high water resistance without losing noticeable compressive strength even after one month of soaking time. The findings provide a novel method to apply fly ash as a high-strength, water-resistant precast construction material.

By Pierre Mousset-Jones, Felipe Calizaya

The design of an auxiliary ventilation system for long underground openings (drifts, ramps and shafts), often requires the installation of multiple fans. The fans are installed in series and separated from each other by rigid ducts of fixed or variable length. However, problems relating to excessive leakage often occur, with each project representing a unique problem requiring an efficient solution. In this study, a method to determine the design parameters of an auxiliary ventilation system is presented. The method is based on the principle of partitioning a long ductwork into segments of finite length and solving the resulting networks separately. Specifically, the method is developed to solve two types of problems: constant fan spacing, and constant fan size. In the former, the fan spacing is fixed, and the problem is solved for fan sizes. In the latter, the problem is to solve for fan spacing. An example is used to illustrate the method.

Jan 1, 1993

By G. H. Schnakenberg Jr.

In response to the underground mining industry's growing concern with the exposure of workers to the diesel particulate matter (DPM) component of diesel exhaust, a method was developed to estimate the average workplace concentration of DPM that could be expected from using the new lower DPMemitting engines now being approved by the US Mine Safety and Health Administration (MSHA) when these new engines are equipped with state-of-the-art exhaustcontrol technology for filtering and combusting DPM. The resulting estimate uses the MSHA-reported particulate index for these engines, the prevailing rule-of-thumb ventilation rate of 150 cfm/hp and the available diesel-exhaust filter technology that has been shown to be at least 80% effective in reducing tailpipe DPM. In the estimate calculation, every engine used in an underground mine is assumed to be equipped with this control technology. Under the stated reasonable conditions, an average DPM level of 90 µg/m3 (mass) is predicted as technically feasible.

Jan 1, 2002

By Stanislaw Wasilewski, Zdzislaw Krzystanek

The CMC-3 new generation system for continuous methane monitoring enables on-line measurement of methane concentration within the range of 0-100% CH4 with a great autonomy of operation. In principle the system has been worked out in the asspect of hazard detection in mines endangered with rock and gas outbursts. But after last crash in the Halemba colliery, according to the recommendation of the after-accident committee, the system was directed to this colliery for operational tests. The paper describes construction and functions of this system and gives some results of tests conducted at the Halemba colliery. The results point out the necessity of using monitoring equipment of continuous operation in mines of high dynamics of methane emission. INTRODUCTION Commonly used in Polish coal mining the methane monitoring systems of CTT/63/46 Up or CMM-20 and CMC-1 type are based on cyclic measurements with 4-minute repetition of measurements. This period has been stated sufficient from viewpoint of methane emission dynamics under normal exploatation. In these systems, automatic switching-off electrical power is performed by the surface station, i.e in case of detecting exceeded concentration value the station generates control pulse signal which actuates the switchng-off devices CRA and IZZO. Such a way of disconnection causes a considerable time delay, up to several minutes, in electric power break at hazardous areas. In the methane monitoring system with the new CMC-3 station, the different phylosophy of operation has been applied. Measurement of methane concentration is performed in a continnous way. In case of exceeding the alarm value, immediate control of the IZZO unit directly by methane monitor follows and consequently energy break without necessity of communicating with the surface station. Alarm values are set directly in methane monitor. The system ensures central powering of underground equipment from the surface, and in case of power failure the methane monitor equipped with battery operates autonomously for about 12 hours. Such an extention of the methane monitor funtionality has been achieved thanks to the use of internal microprocessor controller. The system with the CMC-3 station has been worked out in the aspect of methane hazard detection in mines exposed to gas outbursts. But after last gas explosion, according the desicion of the After-accident Commitee, the system was installed in the Halemba coliery where it underwent operational tests. Besides

Jan 1, 1993

By Lucien Duckstein

The purpose of this paper is to give recommendations for utilization of water resources in a mining region, considering also water supply and environment; the case study of mining for coal and bauxite under the karstic aquifer of the Transdanubian mountain of Hungary is used to illustrate the approach, which consists in formulating a static multiobjective control model and solving it by compromise programming. The three activities of regional mineral resource exploitation, water supply and environmental protection are represented by different objectives which cannot be expressed in commensuerable units. Thus, a solution which is optimal for one objective is usually far from being optimal with respect to the other two objectives. As a result, we are not seeking an optimal solution for the conjunctive regional system, but a good compromise, trade-off or "satisfactum" (1), (2).

Jan 1, 1979

By J. R. England, W. J. Taylor

The Sudbury Basin is the scene of the mining operations of the Ontario Division of the International Nickel Company of Canada, Limited. Around the rim of the geological formation and within thirty miles of the City of Sudbury are located twelve operating mines and one open pit operated by the Company. The City, with a metropolitan population of some 100,000 lies 240 miles Northwest of Toronto. In addition, there is one mine in Northwestern Ontario, at Shebandowan, 700 miles Northwest of Sudbury. In 1973 these mines produced 16.5 million short tons of ore of which 14.9 million tons were from underground and the balance from open pit operations. Mining methods include blasthole, sublevel caving, induced caving, shrinkage, cut-and-fill and undercut-and-fill. Raise boring commenced at Inco in 1964 and is now applied at all mines in the Sudbury District (Figure 1). [ ]

Jan 1, 1974

By L. G. Austin

Development of an equation for tumbling charge and balls plus comparison to plant data suggests that the net mill power for cylindrical semiautogenous mills can be calculated from

Jan 1, 1991

By C. B. Alcock

The control of high temperature processes requires the ability to measure significant variables during operations. With increasing automatic computerized control there is need for sensors which can provide on-line chemical analyses of all phases present in a reactor without the necessity to withdraw samples from the high temperature reaction zone. Probes using electrochemical cells and conductivity measuring devices have provided the answers to some of these problems, notably the measurement of oxygen in liquid metals, and similar potential systems based on the same fundamental principles for the analysis of non-metallic and metallic elements appear feasible. In this discussion, the state-of-the-art in chemical sensors will be discussed in terms of the potential materials of construction, and, in some cases, the limitations of upper temperature at which some promising systems can, at present, be applied. It is concluded that a new phase of basic research could improve the outlook substantially by providing solutions for some problems in chemical sensors which are now well-defined.

Jan 1, 1990

By G. A. Gordon

For the purpose of examining a specific problem, it is important that we look at the context, to obtain an appreciation of the general area of which the particular problem forms a part. It is my task today to speak on a particular relationship between the nations of Canada and the United States of America. What is the background? Almost two hundred years ago we both belonged to a family of nations -- the British Empire. There was a serious family quarrel in 1776 and the United States left the family and set out to make its own independent way in the world. Canada, which was not as grown up as the united States, remained with the mother country, and in 1812 resisted a vigorous attempt by the United States to get it to leave home too. With the passing of the years the bitterness of that family quarrel has faded and, aside from occasional differences, we have been getting along very well ever since.

Jan 1, 1962

By D. G. Millette, A. J. S. (Sam) Spearing

The design of a cost effective backfill system involves many aspects and various inputs from different engineering disciplines. Backfilling is a very significant mining cost and efforts need to be made in the design stage to maximise efficiency and flexibility whilst minimising costs. The aspects that need to be considered include the following: Required fill performance underground Peak and average fill tonnage requirements Backfill scheduling in the mining cycle Material selection, testing and preliminary costing Plant design and storage needs Infrastructure requirements Implications on surface waste/tailings disposal and costs Total backfill costs In order to produce a cost effective and efficient backfill operation, a multi-disciplinary project team is required that should include the following skills and functions: Mine Planning Rock Engineering Metallurgy Mechanical Engineering Environmental Health and Safety Tailings Disposal/Waste Management This paper discusses the above and indicates important aspects that should be considered.

Jan 1, 2001

By H. E. M. N. Moursy, M. N. Ahmad, C. R. Holland, G. M. Walker, R. D. Chandler

This work describes the effect of process parameters on the acidulation of Moroccan phosphate rock using nitric acid, i.e., the nitro-phosphate process. A series of bench scale experiments were conducted, using a stirred tank reactor (STR) system, to investigate the chemical reactions involved and optimum conditions for the formation of nitro-phosphate fertilizer. The effect of reaction time, temperature, mixing speed, acidulation ratio, and acid concentration were investigated, and were found to have an effect on the dissolution of P2O5 from the phosphate rock, using nitric acid. An increase in nitric acid concentration resulted in an increase in P2O5 dissolution, however, the dissolution was also found to be a function of acidulation ratio. A nitric acid phosphate rock ratio of 4:l ensured 90% dissolution for nitric acid concentration > 30%.

Jan 1, 2002

By K. Nuttall, S. Vijayan, A. J. Meinyk, R. D. Singh

For conventional applications, there is limited demand for rare earth elements as well as yttrium and scandium. But the emergence of new high technology applications such as supermagnets, lasers, and superconductors should result in significant demand for some of these elements. This article examines the anticipated applications and demands for rare earth elements over the next decade. It also looks at the implications on the use of available resources. In the context of a growing demand, process methods are reviewed for the recovery of rare earth elements from conventional and unconventional resources. And the article also discusses the challenges facing the mining industry in meeting this opportunity. Reserves and reserve base The rare earths (RE) are a homogeneous group of metallic elements occupying the area from lanthanum to lutetium in group IIIB of the periodic table. Yttrium and scandium are also included with the rare earths because of their chemical similarities and common existence in nature. These 17 elements and their atomic numbers are shown in Table 1. The rare earths are widely distributed in low concentrations throughout the earth's crust (Hedrick, 1985). They occur in many rock formations including basalts, granites, shales, and silicate rocks at concentrations of 10 - 300 ug/g. They also occur in more than 160 discrete minerals. Most of these are rare, but may contain as much as 60% rare earth oxides (REO). More than 95% of the REO occurs in three minerals: monazite and bastnasite for the light rare earths and xenotime for yttrium and the heavy rare earths. Apatite and multiple-oxide minerals, such as euxenite and loparite, are also commercial sources of the lanthanides and yt-trium. Rare earths do not occur in nature in the elemental state. And, except for scandium, they do not occur in minerals as individual compounds. Bastnasite and monazite are the two major minerals used commercially to supply most of the rare earths (Hedrick, 1985). Bastnasite is a key raw material source for the cerium subgroup elements. The largest known bastnasite deposit occurs with iron ore minerals in China. The second largest deposit is situated in California. Typical rock analyses of the fluorocarbonate mineral bastnasite deposit in California show about 15% bastnasite. The REO content of that is about 50%. Monazite is present in beach sands in many parts of the world. This includes India, Brazil, Australia, South Africa, the

Jan 1, 1989

By R. J. Sweigard, G. T. Lineberry, B. K. Slone, F. A. James III, D. S. Maggard

The depth at which it becomes more economical to use slope access instead of box-cut access for nearsurface coal reserves is termed the "transition depth." The transition depth can be established for a given coal property by considering cost estimates for those parameters that determine respective access methods. Fourteen parameters that influence access cost were identified, and ranges for these parameters were determined. A transitiondepth formula was developed to permit the determination of which is the better method of accessing a reserve, given information such as high wall slope, road width, total bench width, pit dimensions, road grade, belt component costs, pumping costs and the cost of overburden removal and reclamation. In most cases in Appalachia, especially in eastern Kentucky, the observed transition depth ranges from 20 to 30 m (66 to l00 ft). This indicates that actual practice is consistent with the analytical approach used.

Jan 1, 2002

By J. Guzman

Introduction The Carlin Trend is North America's premier gold producing district. It is located in northeastern Nevada's Elko and Eureka Counties along a northwest trending belt about 65 km (40 miles) long and 8 km (5 miles) wide (Thorstad, 1989; Jones, 1989). This trend is the worldwide reference site for epithermal, sedimentary rock-hosted microscopic gold deposits. At least 19 deposits have been discovered to date, varying in size from 933 kg to 1.08 kt (30,000 to 35 million contained oz) of gold (Fig. 1). Newmont Gold Co. and its parent, Newmont Mining Corp., jointly constitute the largest mineral right holders in the district. They own or control more than 1000 km' (386 sq miles) in and around the Carlin Trend and own all or part of I6out of the 19 mines and prospects identified to date. Since the initiation of Newmont's exploration activities in the Carlin Trend in 1961, 2.24 kt (72 million oz) of cumulative gold resources have been identified. Cumulative production from all mines since the start-up of Newmont's Carlin mine in 1965 to the end of 1989 was about 202 t (6.5 million oz) (Jones, 1989). The incentive of sustained high gold prices and innovation in processing technology resulted in a significant acceleration of gold output over the last few years. Newmont Gold alone produced more than 43.5 t (1.4 million oz) in 1989. That is equal to 22% of the cumulative 1965 to 1988 output, and an almost 200% increase over its 1986 output. The same incentives produced even more spectacular exploration results. In each of the last five years, net additions to reserves and resources outpaced current production by substantial margins. These facts demonstrate the spectacular past prospectiveness of the Carlin Trend and the success of focused, multi-disciplinary exploration methods that made it possible to more than offset the recent accelerated depletion of gold resources. However, is this situation sustainable? How long can the mining companies along the Carlin Trend keep on finding resources faster than they deplete them? These are some of the questions that motivated this study. The authors have not quantified the future potential for gold exploration in the Carlin Trend nor established a deposit discovery path. But strong indications were discovered that the [ ] Carlin Trend remains a relatively immature exploration district and that the potential for significant new discoveries is high. Methodology and data The approach chosen to address the above questions was simple. The authors compiled deposit size data, measured in contained ounces of gold resources, for all known deposits along the Carlin Trend (Table 1). The resource information was obtained by adding cumulative historical production (adjusted for mining losses and metallurgical recovery) to 1989 year-end published resource inventories. In a mature exploration area, where most deposits have been discovered, this distribution would be expected to approximate lognormality and would plot along a straight line on a lognormal probability scale. This result was found in previous work by Allais (1957) and recently confirmed by Cox and Singer (USGS, 1986) in regard to various types of mineral deposits in several regions of the world. It was also found to hold true for oil and gas pool size distributions (Arps and Roberts, 1958; Kaufman, 1962; McCrossan, 1969). [ ] The data used were compiled by Newmont Exploration geologists. The purpose of the study is to make inferences about the underlying geologic processes in the district and the maturity of the exploration effort. Therefore, deposits were not classified according to ownership but according to geologic occurrence as known from current information. Newmont's Post and Barrick's Goldstrike and Betze deposits, for example, are shown as a single occurrence to reflect the actual geologic setting. The cumulative frequency distribution of deposit sizes was plotted on lognormal probability paper (Fig. 2). The abscissa shows the cumulative fraction of deposits at or below a certain deposit size and the ordinate shows the deposit size in thousands of ounces of contained gold resources.

Jan 1, 1992

By Michael Karmis, Emily A. Sarver, Ellen S. Gilliland, Leigh-Anne H. Krometis

"Public engagement is increasingly important in ensuring the success of projects related to energy development, particularly with regard to issues of environmental protection, public health, and socio-economic impacts. This is due to concurrent trends in public behavior, including a rise in public interest in these projects that is not matched by a rise in science literacy, and increasing organization and participation of the public through social media, citizen science, and grassroots initiatives. In recent years, several high-profile incidents have demonstrated that when public concern is ignored or met with a passive response from industry, it can rapidly grow into organized opposition that negatively impacts or wholly derails a project. Engaging, listening to, and educating stakeholders during early planning and development phases are therefore essential to earning credibility and trust. Moreover, maintaining two-way lines of communication throughout the lifespan of a project demonstrates social responsibility and facilitates cooperation, acceptance, and even support from communities and others. Positive experiences with specific projects at a local, community level can influence the larger public opinion of an entire industry sector. This paper presents cases studies of public engagement related to shale gas development (including hydraulic fracturing and pipeline construction), mountaintop removal mining, and management of mixed-use watersheds near surface mining operations. The experiences highlighted in these case studies are used to draw best practices of public engagement for sustainable energy development.Introduction Within the scientific research community, the importance of public engagement has gained increasing recognition. In a 2007 article in Nature, medical researcher, Patrick Taylor, stated that public engagement has both “gone viral” and “gone global” and has the ability to make real impacts to research (Taylor 2007). Nancy Baron, the science outreach director for COMPASS, an organization providing communications training for scientists, provides further evidence for the increasing focus on engagement, including shifting attitudes observed during her own experience as a communications coach and documented in surveys, the recent inclusion of communication and engagement activities in academic tenure review, and the surge of workshops, materials, and other resources available on the subject (Baron 2016). In addition to COMPASS, a number of organizations and institutes have been developed to train scientists for communication and engagement with the public, perhaps most notably the Alan Alda Center for Communicating Science at Stony Brook University, and academic fellowship programs, such as the Leopold Leadership Program at Stanford University and the Wilburforce Fellowship Program, have been established for the same purpose."

Jan 1, 2017