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By S. Ersayin

In 1998, the Concentrator Modeling Center was established within the Coleraine Minerals Research Lab to develop models for simulation of iron ore processing plants, and to assist plant operators in improving performance of their aging plants. The short-term objective was to develop necessary models for reliable simulation using conventional techniques, while the long-term objective was set as liberation-based modeling and simulation of these plants. The short-term objective was achieved in 2002, after the development of models for magnetic separators, hydroseparators and fine screens. A project funded the US Department of Energy was carried out to demonstrate the capability in improving iron ore processing at the Mittal plant. As a result of this study, a 10% improvement in throughput at the plant was obtained, and simulation became a desired tool for plant operators. A significant step in the long-term objective was reached in 2005 with the development of a liberation model. This was followed by incorporation of models capable of processing liberation data into the software. By early 2007, the Center had the capability of performing liberation-based simulation of entire plants.

Jan 1, 2008

By Robert F. Shurtz

This paper suggests that pre-occupation with the random process model notised by geostatisticians may result in neglect of more promising techniques, especially since the random process model does not appear to be essential to current geostatistical procedures. This point of view is emphasized pictorially. To emphasize the potential of new techniques a simple application of the conventional Brownian function is described. The probabilities estimated in this truly random way are different from those estimated by Kriging

Jan 1, 1980

By D. J. Gilbert

As a preventive action, the geotechnical department at the mine analyzed the original topography overlying a conveyor tunnel at the mine. Several dewatering drains were installed to intercept water collecting from an old lakebed. Subsequently, 20 steel arches were installed to provide additional support in an area of tunnel where original geological mapping indicated Type IV rock. This project was completed ontime with no loss to production. Construction schedules had to be developed to half hour precision, to accommodate the installation.

Jan 1, 2011

By Vernon K. Garrett, Gerhard Sauer

INTRODUCTION Generations of tunneling engineers had to fight not only against bursting rock and squeezing ground but also against the destroying power of water. Intrusion of groundwater into the tunnel opening affects the stability of the tunnel support system, reduces the safety of the traffic inside the tunnel, induces corrosion of installed equipment, and provides for creeping currents at electric facilities. Aware of these problems, engineers of the Washington Metropolitan Area Transit Authority and their consultants opened the way for a new approach in sealing a tunnel. It was made possible by accepting a new method of tunnel construction scarcely applied in the U.S. before. This new technique, the New Austrian Tunneling Method (NATM), provided the basis for the successful installation of a PVC-membrane between two separated shells of tunnel lining, and the carefully directed drainage of groundwater. Beside of the economic benefits already attained by applying the NATM for tunnel construction, the Authority now saves millions of dollars otherwise necessary to maintain the tunnel during its lifetime (Garrett, 1986; Setzer, 1986). But there is a large number of leaking tunnels built according to conventional methods, some of them facing severe problems jeopardizing the safe utilization of these structures. Recently developed methods indicate that even those tunnels can be rehabilitated without extensive costs by draining and sealing them afterwards. A road tunnel in the Austrian Alps provides the scene for a major attempt to convert one of those leaking tunnels into a dry structure.

Jan 1, 1987

By J. C. Haptonstall

The Bismark Mine is located in northern Chihuahua, Mexico, 150 km (95 miles) southwest of Ciudad Juarez (Fig.1). The ore deposit was discovered in 1979 and was placed in production in 1992. The production rate is about 2.4 kt/d (2650 stpd) from an ore reserve of 8.5 Mt (9.3 million st). Grades currently average about 8% zinc, 0.5% lead, 0.2% copper and 50 g/t (1.46 oz/st) silver. Substantial inflows of water into the underground mine complicate the operation. Complex metallurgy poses another challenge for the operators. Bismark is a joint venture with 90% participation by Minas Penoles, SA de CR of Mexico City and 10% participation by Promociones Industriales Banamex, S A de C V (PIB S A) of Mexico City. Anew company, Minera Bismark, SA de CV was formed to operate the property. Cyprus Minerals was a 40% participant in the joint venture but, in early 1993, sold its share to Minas Penoles. The Bismark Mine is one of the largest new underground mining projects built in Mexico during the last 10 years. It is the country's fifth largest underground metal mine and provides about 1 % of the world's zinc supply at about 50 t/a (55,000 stpy). Bismark is a trackless operation with overall productivities of 7.6 t/manshift (8.4 st/manshift). The 2.4-kt/d (2650-stpd) concentrator started up in March 1992.

Jan 1, 1994

By C. L. Kosmoski

The mining industry faces many workplace hazards that are a threat to human health and safety. The Bureau of Labor Statistics has found that employees in coal mining are more likely to be killed or sustain an injury or illness than workers in private industry. These injuries are also likely to be more severe (Bureau of Labor Statistics, 2007). In recent years, coal mining injuries have attained national attention due to highly publicized disasters. Despite these threats to worker safety and health, the U.S. relies on the mining of coal to meet its need for electrical power, with42% of electricity in the U.S. generated through the burning of coal (U.S. Energy Information Administration, 2012b; United Mine Workers of America, n.d.). Furthermore, the production of coal continues to increase and reach record levels every year(National Mining Association, 2012; U.S. Energy Information Administration, 2012a). For this reason, the coal mining industry must continue to find ways to protect its workers while maintaining productivity. One potential approach to protecting workers while maintaining productivity is through improving the safety culture at coal mines. In order to achieve this culture, operators, employees, the inspectorate, etc. must share a fundamental commitment to safety as a value. This type of culture is known in other industries as a ?safety culture? and can be defined as the characteristics of the work environment, such as the norms, rules, and common understandings that influence facility personnel?s perceptions of the importance that the organization places on safety. Fundamental to improving safety culture within an organization is understanding the existing safety culture; improvements cannot be made without first elucidating areas that require improvement. This manuscript details the process undertaken by researchers at the National Institute for Occupational Safety and Health (NIOSH) Office of Mine Safety and Health Research (OMSHR) to assess the safety culture at five underground coal mines across the United States. The purpose of this manuscript is to introduce the mining industry to a multi-methodological approach to safety culture assessments. Further, it is the goal of this manuscript to highlight the value of including both quantitative and qualitative methods into safety culture assessments in order to obtain the most comprehensive view of an organization?s safety culture. Because this manuscript focuses solely on the methodology implemented, data and results obtained during the five safety culture assessments will not be presented in this manuscript, but will appear in a future publication.

Feb 27, 2013

By J. Leinart

As is readily apparent, the reliability of the early-stage costs estimated for any mining project are critical to the viability of that project. An estimate too high might leave a potentially profitable deposit undeveloped or worse yet, available to a competitor. One too low might waste investment dollars in a project not yet economically ripe. There are two aspects critical to any estimate: 1. The cost data used to represent the values of the wages, salaries, supplies, and equipment. 2. The design used to determine the engineering parameters upon which the above estimated values are based. Given that all of the information contained in Mining Cost Service is provided by suppliers, equipment manufacturers and mine operators, one wonders why there is any question as to the reliability of cost estimates developed using this information. Given that it is all actual (as opposed to statistically derived) data, where do the problems with estimate reliability lie and what is the impact of the data on that reliability? The following presents a series of analyses designed to assess the reliability of the cost estimating process. Both the actual cost data and the engineering parameters upon which they are based are examined in an attempt to quantify and understand the importance of each. While several sources of cost information are available (Means, Richardson, Primedia?s Equipment Watch, and individual suppliers and manufacturers), the following rely solely on data contained in InfoMine USA, Inc?s, Mining Cost Service and in its Sherpa Mine Cost Estimating Software.

Feb 27, 2013

Coal preparation plant simulators are used to study flowsheet alternatives and determine product quality and quantity that can be produced under various operating conditions for individual circuits. Some simulators also provide an estimate of the cost per ton of clean coal by determining the number and size of different processing units required for a specific raw coal tonnage and by computing both capital and operating costs for individual units. However, to the authors? knowledge, none of these simulators have the ability to optimize plant performance while satisfying multiple product quality constraints and selecting the most profitable flowsheet from many alternatives. A novel coal preparation plant simulator (SIU-Sim) that maximizes the overall plant yield using a robust optimization tool and selects the best plant cleaning circuit configuration based on maximum plant profitability is presented. The simulator also identifies the best operating conditions for individual circuits of a plant to satisfy multiple quality constraints for the overall clean coal product. It uses a genetic algorithms- (GA) based technique to maximize the overall plant yield for each cleaning flowsheet alternative and uses a net present value (NPV) analysis technique to maximize plant profitability for the entire life of a new plant or the remaining life of an existing plant. The step-by-step development of the simulator along with a case study demonstrating its specific features is presented.

Jan 1, 2008

By Jerry C. Tien

Changes and the pace of change in China’s coal industry have been extraordinary during the past several years. At least 35 of the 94 former coal bureaus have been restructured into different mining companies and groups. Some of the more productive and efficient ones were further strengthened through consolidation and expansions. And several have even formed, or are in the process of forming, strategic alliances with utility companies, railroads, ports and chemical companies to secure additional reserves and coal sales. In addition, the improvement in coal pricing during the past two years has enabled China’s coal industry to move ahead with some needed changes. Coal mining accidents, though, remain a major concern for the Chinese government. Accidents remain high even though the government has made efforts to shutdown more than 55,000 unlicensed, unsafe small coal operations throughout the country.

Jan 1, 2003

By T. B. Acton

There are two types of ore transportation systems in use at Newmont's Magma Copper Co. San Manuel mine in Arizona-rail-mounted, box-type rotary cars and the newer rail-mounted, bottom-dumping ASEA cars. Though the cost per car for the ASEA units greatly exceeds the cost per rotary car, the advantages of the ASEA units, including much faster dump times, have made the ASEA system a successful alternative at the San Manuel mine. The rotary system of ore transportation has been in use at San Manuel since production began in 1956. The system employs 7.9-m3 box-type cars to transport ore by rail to shaft pocket areas. A rotating dumping mechanism turns three cars at a time upside down to empty them, and returns them to an upright position. Trains of 15 cars each are dumped in about six minutes. Each 15-car train is pulled by an 18-t rated trolley locomotive. There are about 400 rotary cars in service at San Manuel and the system is used for the majority of ore haulage. This well-proven rotary method was instrumental in achieving the December 1977 world record of 272 Mt hoisted from an underground copper mine. Magma Copper Co. began using ASEA cars in late 1977. Designed by ASEA of Sweden, the cars are built for San Manuel by Kasper-Hall Manufacturing Co. in Tucson. The cars basic design feature is a hinged floor that opens at the side as the car is pulled through the dump. As it passes over the dump, a fifth wheel attached to the hinged floor (opposite the hinges) travels along a rail in the dump. This rail dips down into the pocket and then returns to track level. As the fifth wheel travels along the rail, the car floor opens, the car dumps, and the floor is then returned to track level. As the car is dumping, the body remains suspended over the pocket by wheel rollers attached to each side of the dump. Trains of 10 cars each are emptied in about 45-50 seconds. Each ASEA train is pulled by an 18-t rated trolley locomotive, adapted at San Manuel to allow it to pass through the ASEA dump. At minimal cost, "wings" are welded to each side of the locomotive. These wings suspend the locomotive over the pocket as the train passes through the dump. Advantages of the ASEA System Major design characteristics of the ASEA and rotary systems are shown in the accompanying table. The comparison points out some of the following advantages demonstrated by the ASEA system. • Faster dumping-An ASEA train dumps in 50 seconds, while a rotary train takes at least six minutes. There is no stopping or starting when dumping an ASEA train. The train enters the dump area, dumps, and leaves in one continuous motion-in contrast to rotary trains which must stop and start five times to dump. With the rotary system, three cars are spotted in the dump mechanism by remote control. When the cars are in place, the train operator activates the dump, the cars are turned over, and then returned to an upright position. This process is repeated until all 15 cars in the train are emptied.

Jan 4, 1980

By Shawn Orser, Jennifer Waddell, Mike Sierakowski, Tom Barrett

Production evaluations were conducted at Daisy Gold Mine (Glamis Gold, formerly Rayrock), between August, 1997 and August, 1998 to quantify the effect of 3M fluorochemical surfactants (fluorosurfactants) on extraction kinetics and gold recovery in gold heap leach mining operations. Ore was treated at a level of 7-10 grams surfactant per ton of ore using 3M Pluorad TM Leach Mining Additive PC-GOLD. Kinetics and gold recovery were determined by solution assay for each of the tests. Both tests indicated improved kinetics, and data from Test 2 was used for determination of a quantitative increase in gold recovery resulting from PC-GOLD addition. A discussion of test results including methods used to determine gold recovery is provided.

Jan 1, 2000

By Lloyd M. English

During the past 30 years, the research arena has changed significantly in all fields, mining included. The relative representation of the topics of research, how the research is performed and who has performed the research have all changed. Although there are a lot of subjective ideas and anecdotal "analyses" concerning these changes, there has been no actual study of these trends to verify the facts. This study was divided into six five-¬year periods for the purposes of comparison. Some of the trends analyzed are co-authorship, research areas, research sponsors and cooperative efforts. In today's research arena, 30 years is a long time. Technology has advanced more rapidly than in any time previously and that pace continues to increase. There are more researchers, more tools for research and an increasing number of companies, agencies and institutions engaged in research. The pace of change and its impact is often discussed and debated at professional meetings and in institutions that engage in research. These conversations will often influence the research decisions of the participants in directions to take or subjects to pursue.

Jan 1, 1995

By J. David Lowell

The first part of this article is a review of industry techniques and styles during the past 50 years. It is followed by my career history during the same period. The second part covers my ideas about what works in mineral exploration. These include estimates about discovery costs, thoughts about education of explorationists, organization of exploration groups and my opinions about the relative value of exploration techniques. Evolution of exploration techniques [Table 1] shows the evolution of mineral exploration techniques and styles from 1950 to 2000. During the first half of that period, there was a progressive increase in exploration drilling. During the second half, there was a decrease in prospecting and an increase in high technology, indirect exploration and a rapid increase in discovery cost.

Jan 1, 2000

By J. D. Miller, C. L. Lin

As the techniques and resolution for 3-D spatial analysis have advanced in the last decade, it is now possible to map in detail the microstructure of multiphase materials in three-dimensional digital space. In this regard, three-dimensional x-ray microtomography offers a unique imaging capability. Spatial resolution on the order of ten microns can be achieved with the use of microfocus x-ray generators. Recently, a state-of-the-art cone beam x-ray microtomography system has been installed at the University of Utah for the quantitative analysis of multiphase materials in three dimensions. This facility has been designed to obtain 2048 x 2048 pixel reconstruction over a 10-mm diameter, while also allowing for the imaging of somewhat larger (40-mm) objects. The system is capable of handling high-density materials, even materials having a density as high as 8.0 g/cm3. This unique, one-of-a-kind, instrument will be used to obtain three-dimensional spatial reconstruction for such applications as specific examples 3D liberation analysis, pore structure analysis of particle beds during filtration and air-void system of concrete structures. The utilization of x-ray microtomography not only will allow for quantitative analysis of multiphase systems but also allow for textural characterization and the determination of phase continuity. In this paper, we present information regarding the current use of this new facility and reviewed potential applications for the advanced analytical system.

Jan 1, 2001

By George Wilson

When pumping abrasive slurry mixtures, special attention must be given to pump design and construction. The second article in this two-part series describes some design features to consider when selecting centrifugal slurry pumps. Hydraulic Design Most centrifugal pumps are conventionally designed to achieve the desired hydraulic performance at the highest efficiency and lowest cost when handling clear fluids in reasonably clean environments. Manufacturing limitations are not imposed on the configuration of the pump, since conventional materials such as cast iron, bronze, and stainless steel are used. Manufacturers and buyers usually select the highest specific speed commensurate with the lowest cost attainable. Part life is almost infinite. When a centrifugal pump is designed for slurry service, the important factors in pump design are wear and materials of construction; size and efficiency assume lesser importance. The pump must operate at low rotational speed and the impeller has to be a truly radial flow design. These factors immediately determine that the pump must be of a low specific speed design in the range of 600 to 1800. The specific speed is a type number that is constant for all geometrically similar pumps; it designates the geometry of the impeller and casing. [ ] where n = rpm, Q = flow (US gpm), H = total head (ft), and Ns = specific speed. Since wear is a function of velocity it can be shown that for a given head and capacity, wear will increase with increased Ns. Centrifugal Pump Casing The casing has a profound effect on performance. If designed incorrectly it can destroy a large part of the energy given to the flow by the impeller, resulting in low efficiency, high hydraulic forces, and excessive wear on both the casing and impeller. In a conventional spiral volute, the static pressure around the impeller is uniform only when there is a free vortex velocity distribution in the volute, i.e., when the spiral flow from the impeller coincides with that of the volute spiral. This occurs only at the best efficiency point (BEP), between the pump's best operating zone and over capacity zone. Departure from the free vortex velocity distribution in the volute at partial or over capacities produces circumferential pressure gradients at the impeller periphery, which is directly proportional to the specific gravity of the mixture being pumped. At partial or over capacities, the flow will not tolerate the abrupt deflection at the tongue and severe energy losses and wear are created near the casing throat and on the impeller. Concentric and semi-concentric volute designs produce uniform static pressures at the impeller periphery and make the pump, much less sensitive to "off"' BEP operation. Hydraulic forces and wear are considerably reduced-eliminating the tongue prevents abrupt deflection of the flow, turbulence is minimized, and the velocity in the casing volute and throat is reduced. Good efficiency is sustained over a wider operating hand. Casings of this design are easy to cast. • Spiral volute (conventional)-Radius to the outer periphery of the casing and the volute area constantly increases. • Semi-concentric casing-Radius to the outer periphery of the casing and volute area remain constant within a certain angle. • Concentric casing-Radius to the outer periphery of the casing and volute area remain constant through 360°. The degree of concentricity must be reconciled with efficiency, hydraulic radial load, and wear for each specific speed chosen. Up to 1200 Ns the casings can be fully concentric without sacrificing too much efficiency. Above 1200 Ns, the casings can be semi-concentric. The angle of concentricity

Jan 10, 1981

By Louis W. Cope

Since its discovery, Cuba has been called the “Pearl of the Antilles.” The country remains that, albeit a little tarnished these days. In Havana, many of the buildings are being refurbished, while some new ones are under construction. Since 1991, the laws have been relaxed so that Cuba is developing a mixed economy of central control with free market. Joint venture agreements have been signed with businesses from many countries. This does not include the United States due to its embargo. But even these regulations have been relaxed some.

Jan 1, 2003

By Jamie Bonner, Ray Hutton, Taro Nonaka

The Nancy Creek Tunnel is a deep tunnel, designed to store and convey wastewater by diverting flows from trunk sewers currently at or near capacity in the northwest of the City of Atlanta. The tunnel, constructed in hard rock, has an overall length of 13,300 m (43,700 ft), and a finished diameter of 4.9 m (16 ft). The project is currently under construction by a joint venture of Obayashi/CJB for the City’s Department of Watershed Management. This paper describes the contractor’s techniques and equipment, as well as discussing challenges which were overcome. The project is scheduled to be complete in October 2005.

Jan 1, 2005

By D. Shin

The gold leaching using cyanide from ore or waste has been almost universally in use [1]. Recently, biological gold bioleaching using cyanide producing bacteria, e.g. Chromobacterium violaceum, Pseudomonas fluorescens, or P. aeruginosa, has been investigated as environmental friendly and cost effective method. Among them, C. violaceum has been reported as effective cyanide producing bacterium on gold leaching [2, 3]. C. violaceum produces cyanide using glycine as a direct precursor and subsequently detoxify the cyanide by ß-cyanoalanine synthase [4]. However, until today only 0.026 ? 16.9 mg/L of cyanide production in YP medium has been reported in the literatures by C. violaceum [4-6]. Comparing with adding cyanide chemical, biogenic cyanide concentration is lower than the cyanide concentration added in traditional cyanidation. Since cyanide also forms complexes with a number of other elements such as iron, nickel, zinc, silver, copper, and platinum, it is very important for gold recovery to investigate the enhancement of biological cyanide production and set optimal experimental condition. Most of early studies on gold bioleaching by C. violaceum have been performed to investigate gold leaching mechanism using gold powder, and recently various resources such as ores, electronic scrap, and printed circuit boards of waste electronics [7]. Few studies have dealt with gold bioleaching from low-grade ore. In this research the feasibility of gold bioleaching by C. violaceum from low-grade ores containing gold was evaluated and fundamental study was performed for further scale-up study. The aim of this study was to improve the potential of gold bioleaching by C. violaceum from gold-containing ore; in particular, enhancement of biological cyanide production.

Jan 1, 2012

By Lorraine Brandt Yde

This paper describes development of a cost report that is descriptive, logically oriented, and concise. Since the costs involved relate to mining, this reporting technique could help bridge any possible communications gap between "mining men" and computer personnel, at the same time giving the computer-oriented mining individual information to assist him in his job performance. As computers become entrenched in the mining world, meaningful report assimilation becomes a major task. No one should be more capable of defining required results than the man requesting a report. If he is able to clearly state his needs and has researched his problem, it will be reflected in the computer output. During 1970, The Anaconda Company's Berkeley Pit Operation, at Butte, Montana, received many different computer-generated equipment cost reports. Up to thirty-six different components for each type (class) of pit equipment contributed cost data to the Berkeley Pit cost system files for both operating and repairs during current month, year-to-date and accumulation-to-date time periods. This reporting approach was taken to facilitate analyzing this voluminous data. SUMMARY A Major Component Cost Analysis (Exhibits 6-A thru 6-C) developed by arranging the top ten operating and repair percentages (component cost divided by total cost) in descending order, and then accumulating these percentages to a possible one-hundred percent. While tabulating the operating and repair cost percentages by equipment unit number in the current month, year-to-date and accumulation-to-date time periods, a frequency chart is constructed for each equipment

Jan 1, 1971

By Robert C. Speck

The U.S. coal industry has long utilized the pillar-extraction mining technique as a method for maximizing coal recovery. Like longwall mining, it causes large-scale movements that progressively propagate from mine-level to the ground surface and may affect the groundwater regime, surface drainage and surface structures. The U.S. Department of Energy, in an effort to foster in- creased use of total extraction mining techniques, has recognized the need for a better understanding of these movements that will lead to a greater compatibility between coal mining and present and future land use. As part of that goal, GAI Consultants, Inc. is currently in- stalling instrumentation to monitor the ground movements associated with pillar extraction mining at Kitt Energy Corporation's No. 1 mine in northern West Virginia.

Jan 1, 1982