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By Yoginder P. Chugh

The mining methods used at many opencast brown coal mines in Poland and the German Democratic Republic are not used in the US to any extent. Using bucketwheel excavators, bucket chain excavators, and mobile conveyor bridges, the mining techniques may offer efficient, economic alternatives for operators in the US. These mining methods were observed during visits to several open-cast brown coal mines in Eastern Europe over the past two years. Some of them may be particularly attractive for the large lignite mines being planned in North Dakota and Texas.

Jan 11, 1980

By Yoginder P. Chugh

Most mines are large producing 0-25 mmt annually. The coal is mine.) at depths ranging from .0-150 m 120-500 ft mining at 300 m .(,1000 ft) depth is anticipated in the future. Single and multiple seams ranging from 3-12 m 10-40 ft) in thickness are mined. Most overburden is unconsolidated and consists of sands, and sandy or silty clays. The stripping ratio (volume of overburden to volume of coal mined) varies from 3-L. The overburden and coal is mined in benches 8-12 m -(24-40ft) high; the high-wall angle is about 45 degrees. Bucket wheel and bucket chain excavators are commonly utilized for overburden and coal removal, Some of the large overburden stripping machines nave capacities. Ranging from 4400-10,000 bank cu ( 6000-14,000 BC) per hour. The overburden from the upper benches is transported around the pit using the trains and belt conveyors. It is deposited in the spoils using large stacker-conveyor systems capable of handling 2550-7300 cu m/hour (7500-10,000 cu yds/hour). The overburden from the bottom two or three benches is transported across the pit using the conveyor bridges which are computer controlled. Conveyor bridges capable of handling overburden up to 60 m (200 ft) high are currently in use; a 60 a (20e ft) high conveyor bridge has a capacity of 85 x 10 cu ( 118 x 10 cu yd) annually. The coal is loaded in the trains directly and shipped to power plants or coke oven plants.

Jan 1, 1980

By J. R. Brett

Utah Development Company (UDC) operates five large opencut coal mines in the Bowen Basin of Central Queensland, Australia. In total, over 20 million tonnes of coking coal are exported annually from the five mines. Typically, the coal seams dip at 5 percent, are 2 to 10 metres thick, and sub-crop some 20 to 40 metres below surface. In the main, the operations are single seam, but multiseam (2, 3 or 4 seams) operations do exist and will form an increasing proportion of the mining activities as depths increase. Draglines are used as the major stripping equipment, highwall depths currently ranging from 20 to 65 metres. Whilst project feasibilities were based on stripping to a 60 metre highwall, it is now proposed to continue opencut mining to depths exceeding 100 metres. This will entail large quantities of prestripping (ahead of the draglines) and overcoming problems associated with steepening seam dips, including haulage of coal from the pits.

Jan 1, 1982

By Victor L. Steven

10.1-SHAFT SINKING AND RAISING BY CONVENTIONAL METHODS VICTOR L. STEVEN 10.1.1-SHAFT SELECTION A great deal of thought and planning should go into the selection of a mine shaft to provide the most effective use over the greatest, period of time. It sometimes is better to make an additional capital expenditure in the initial shaft program to achieve the greatest overall shaft usage. It is possible to sink a shaft which could be used for mine development, and initial production and later convert it to a ventilation, service or escape shaft. It is important to consider a second shaft in the original planning to provide ventilation, an escapeway and services for overall efficient production and safety. A second shaft usually is required to comply with state and federal mining laws. The main items to consider in shaft selection are: 1. Installation from surface or underground. 2. Vertical or inclined (sec Sec. 10.1.4L for discussion of factors involved in choice). 3. Tonnage to be hoisted. 4. Size of mining equipment to be lowered through the shaft to the underground workings. 5. Amount of water to be handled in the mining operation. 6. Ventilation requirements. 7. Type of ground the shaft is to be sunk through. 8. Position of shaft with relation to ore body. After the main features of a shaft arc determined, such as vertical or inclined, shape, size, type of lining and support, compartments, and shaft. facilities (air, water, ventilation, pump lines, power cahles, etc.), then :I sinking plant and procedures should be planned. At this point it should be decided whether the company will sink the shaft with its own crews or award the job to a competent shaft contractor. Company sinking generally will cost less if competent shaft men are available. Money also will be saved in plant costs, such as for hoist, headframe, compressed air, buildings, etc., as these will be part of the permanent plant and can be used in the sinking operation. Labor costs generally will be lower than contractor construction rates. The advantage of having a contract, or is the speed of completion of the project. Contractors usually have headframes and hoists ready to move on the job immediately and have trained crews ready to complete the project in the shortest possible time. Next, the type of surface sinking plant (hoist, headframe, etc.) should be selected and a determination made whether it is to be temporary or permanent. In most cases it is less expensive to install the permanent, headframe and hoist, and use them for sinking. The type of actual sinking equipment to be used should be evaluated for the most efficient sinking cycle, e.g., mucking method, drilling method, and lining or support means. The proper cycling of drilling, mucking and lining is extremely important in obtaining the most favourable sinking costs. 10.1.2 - GROUND STABILIZATION AND WATER CONTROL Prior to the shaft-sinking operation an investigation should be made into ground-water conditions. If water is anticipated, then pregrouting of the ground

Jan 1, 1973

By J. Engel

The talc deposit in Gemerská Poloma lies 350 to 400 m under the surface; the whole deposit is located at the highest-level drinking-water-source protection zone, therefore, opening in this mining area (a well, a ramp) requires higher investment, operational and water protection costs. The adit, outside the mining area, with a length of 4200 m, rising with a gradient of 3? and a diameter of 10.3 m2, allows free passage/runoff of mining-water through the adit, and guarantees low costs for transporting produced material and equipment. This solution is in total less demanding from both investment and operational point of view.

Jan 1, 2007

By William Tattersall

On behalf of my agency, the Mine Safety and Health Administration, I would like to add my appreciation that all of you could be here today. Previous dust symposia over the years have proved the value of close cooperation among universities, government agencies, and professional societies in advancing knowledge of dust research and development in the interest of miners and the industry. I'll just comment briefly on MSHA's part of the overall effort by all parties to control miners' exposure to respirable coal dust and other airborne dusts. As you know, our agency's congressional mandate is to do what is necessary to assure that miners will have safe and healthful workplaces. In the area of coal mine health, this has meant joining with the mining community in a continuous campaign to keep respirable dust and quartz levels below applicable standards to prevent or reduce disabling coal workers' pneumoconiosis and silicosis arising from excessive exposure to respirable quartz. Currently, our agency is processing about 120,000 coal dust samples taken by MSHA and company people during the year and about 8,000 samples taken from metal and nonmetal mining operations. Our dust program, like other MSHA programs, has benefited from increased computerization of records. The attack on CWP has had the highest priority of government and industry. The goal has been to sharply reduce social costs of suffering victims and their families as well as the associated future payments under the black lung benefits program. During the 1989 fiscal year, about 104,000 former miners received about one and a half billion dollars in benefits. Since the program began, nearly 25 billion dollars have been paid out. Much progress has been made in lowering dust levels in coal mines since the standard of two milligrams per meter of air was established in 1972. Before that time, there was a 4-to-10-percent probability of a miner developing coal workers' pneumoconiosis at typical pre-1972 exposure levels. However, under the maximum respirable dust levels allowed today, this probability has been reduced to about 1 percent. Since average dust levels are lower today, we can expect fewer miners to develop CWP in the future. Out goal continues to be elimination of both coal workers' pneumoconiosis and silicosis in both coal and nonmetal mining. In 1985, MSHA revised its coal mine quartz policy to allow mine operators to submit dust samples used in setting the quartz standard. Previously, only single MSHA samples were used. Even though less than half of the mine operators have taken advantage of this change, it has provided a larger population of samples for analysis then before. Also the policy allows operations that are on a reduced quartz standard to have the standard reviewed every six months. In underground coal mining, the job of roof bolter typically has higher than normal exposures to quartz. About 45 percent of respirable dust samples from roof bolting operations contain more than 5 percent quartz and therefore are put on a reduced quartz standard. One objective of the policy revision was to improve miners' health by follow-up monitoring, and this is being done with roof bolting jobs. MSHA studies of surface coal mining operations have provided data showing that bulldozer operators and highwall rotary drill operators often have high exposure to quartz dust, and our agency is directing enforcement efforts to reducing this hazard. One of the most important responsibilities of MSHA's metal and nonmetal mine health division is the respirable dust sampling program. In the last few years, nearly 3 out of 10 samples have

Jan 1, 1991

By Gregory R. Wagner

As you know, NIOSH is the part of the United States Public Health Service with responsibility for conducting and supporting research leading to prevention and control of occupational diseases and injuries. Some years ago, NIOSH went through a process of identifying and leading occupational health and safety problems in the United States. Candidate problems were evaluated in terms of the number of people affected, the importance of the effects, and how amenable the conditions are to preventive interventions. Lung diseases were ranked first on the resulting list. Diseases from mining continue to contribute substantially to this unfortunate position of prominence. The work of the Generic Center is one of many answers to this critical problem. Although the research is often expressed in terms of dust characterization or dust control, the reality is that high dust levels are much like high blood pressure. No one cares about hypertension per se. We are concerned about the consequences of exposure to untreated high blood pressure--heart disease, kidney disease, and stroke. Similarly, if dusts were truly only a nuisance, there would be little justification for the diverse research program supported by the Bureau of Mines or by NIOSH. But mineral dusts do cause a range of significant health problems: pneumoconiosis, bronchitis, and emphysema. The research supported by the Center is aimed at doing something about them. Within a public health approach to occupational health, we have a hierarchy of interventions. Primary prevention of problems is prevention at the source: solving a problem before it affects a worker. What we call secondary prevention is an attempt to identify health problems at a sufficiently early stage that some intervention will interrupt the disease process or the development of significant impairment. Tertiary prevention refers to rehabilitation of the worker who has already suffered significant loss of function. At NIOSH, and in the Generic Center research programs, the focus is on primary prevention. Basic investigations into those things about specific dusts that promote or reduce toxicity is critical for our understanding of how to prevent disease. Also, the search for engineering solutions to reduce or control dust generation is essential to solving problems of dust over-exposure. But until the engineers create the foolproof safe environment, it will also be necessary to discover better ways to identify the earliest markers of disease. To do this, we must explore and explicate the basic mechanisms of disease through laboratory investigations as well as human observation and physiologic testing. The unique opportunity provided by the Generic Center program and highlighted in this diverse program over the next few days is that these efforts are being carried out in multiple disciplines concurrently. Also, there are periodic small and large gatherings such as this one where investigators have the chance to get together, formally present papers, and informally stimulate each other's progress towards disease prevention. To ignore the potential for this cross-cutting interaction would be a significant loss. To take full advantage of it is potentially revolutionary. I recently pulled out a book I hadn't read since I was an undergraduate. It specifically concerns the nature of intellectual ferment surrounding the development of the concept of a sun-centered rather than an earth-centered universe in the sixteenth century. The book is about more than developments in astronomy: it is a discussion of the nature of scientific revolutions. Scientific revolutions result from the brilliance, insight, and good fortune of the few superimposed on the evolutionary work of the many. They both cause and reflect significant itellectural and social ferment. For example, the revolutionary work of Copernicus in recognizing the limitations of the concept of an earth-centered universe reflected contemporaneous developments in optics, mathematics, physics, economics, and philosophy.

Jan 1, 1991

By John A. Breslin

The U.S. Bureau of Mines develops technology to help ensure that the Nation has an adequate and dependable. supply of minerals at reasonable economic, human, and environmental cost. Our research programs seek improvements for almost every aspect of the mineral production cycle--from evaluating the availability of minerals, removing the ore from the earth, to enhancing the performance of mineral materials. The health and safety of the men and women who work in the Nation's mines and minerals processing plants and the environmental impact of mining and mineral processing are major Bureau research concerns. In recent years, the U.S. mineral industry has found it increasingly difficult to compete for a share of world markets. Many foreign producers benefit from lower production costs and higher grade deposits. Some foreign governments subsidize their mineral industries and impose fewer restrictions with respect to environmental controls and health and safety regulations. If the United States is to compete in world mineral markets, innovative technology must be found to lower the cost of recovering and processing minerals. Mining and mineral processing research by the Bureau identifies ways to help the country maintain a sound, competitive industry and a dependable mineral supply, so vital to economic growth and the national security. This work includes efforts to improve existing techniques and procedures; but more and more of the Bureau's resources are being focused on long-term, high-risk research directed at developing new approaches to mining and mineral activities--approaches like in situ mining. Bureau scientists are studying the mining applications of computer assisted mining and investigating a variety of "high tech" approaches to extractive metallurgy. Such cutting-edge research will be necessary if major advances in health and safety, environmental quality, strategic and critical minerals availability, and overall U.S. competitiveness are to be achieved. It is just such high-risk research that the industry cannot afford to conduct itself, but--in the long run--cannot afford to be without. It is this type of research that will help us arrive at a revolutionary breakthrough rather than small incremental changes in health and safety technology as well as recovery methods. Our mining and mineral processing research is also directed at reducing the Nation's dependence on imports of minerals that have key defense and industrial uses. Some of these strategic and critical minerals are particularly vulnerable to supply disruptions. We are working on technologies that would allow the United States to take advantage of domestic sources of these minerals--sources consisting primarily of deep or low-grade ores, ores with complex mineralogy we do not yet know how to process, and small deposits that are now uneconomical to mine and process. Other research activities focus on ways to reduce the Nation"s consumption of key minerals and increase the recycling of these minerals. The opportunities in this area include coal. The current middle eastern crisis reinforces the need for a stable energy supply--preferably a domestic supply. The extensive reserves of coal in this country are well documented. Perhaps what is not as well recognized is the impact that the price of coal can have on its competitive position both for domestic fuel selection considerations as well as for the ability of this country to compete in the coal export market. Today, the role to the United States is as a reliable, but high-cost exporter of high-quality coal. U.S. export coal competes with supplies from other major suppliers, including Australia, Canada, Poland. If U.S. mining costs were lowered by at least $8 per ton in the year 2000, then coal exports would surge by a projected 46 percent, and U.S steam coal displaces significant quantities of foreign coal imports in Europe. Further cost reductions would make

Jan 1, 1991

By Anthony Harding

In a world of technology and electronic communication, it is easy to forget what engineers do best with a problem: sitting around a table, exchanging views and ideas with sketches and respecting everyone?s view. This was the approach adopted in the project to arrive at a solution for the cross passage opening sup-port for the Seattle University Link Extension. Schedule and space constraints usually impede concurrent cross passage excavation and tunnel boring machine (TBM) operation. And where the space is constrained, opening support solutions that maximize available cross sections are of great benefit. While there are a number of solutions that minimize space, some of these solutions can require expensive steelwork and extensive drilling and fixing. However, following a detailed round-the-table discussion of the options and constraints, it was identified that a shotcrete shell would not only limit obstruction of the space during installation, but also permit easy installation, particularly around services, and avoid costly steelwork and drilling and fixing.

By Madan M. Singh

This section is unique to the Handbook in that it is the only section that deals with underground excavations for nonmining purposes. The editors were of the opinion that the section should be incorporated because the subject matter covered by the chapters is closely related to mining, and many mining engineers are currently involved in these activities. As we enter the decade of the 1990s activities in this category will increase, enhancing the relevance and utility of the material discussed. As the population increases, especially in metropolitan areas, the necessity to go underground will be greater. At the present time, not only are subsurface shopping malls and pedways connecting buildings becoming commonplace, but structures as diverse as the Civil and Mining Engineering Building on the University of Minnesota campus, a road-and-fleet maintenance facility in Multnomah County, OR, and even an ice cream parlor (Dairy Queen) in northern Wisconsin have been constructed underground. Placing utilities below the surface has numerous advantages and is now customary. Rapid transit and highways through tunnels in urban areas have been the norm for many years, but subterranean stormwater reservoirs, power plants, industrial warehouses, and food storage silos are relatively new innovations. The philosophy of underground defense installations is ancient, but their requirements and designs have trans-formed radically as technology advances. The use of under-ground space for disposition of wastes is modern, since it is recently that environmental concerns and waste disposal costs have assumed increased significance.

Jan 1, 2008

By R. Benito

The publication of the Lerchs Grossmann paper in 1965 outlining a threedimensional graph algorithm for ultimate pit definition set the standard for the mining industry regarding pit optimization. Although the algorithm provides a solution from a static standpoint (i.e., assumes instantaneous mining), it is widely used for commercial packages to generate ultimate pit limits and intermediate phases. However, the solutions delivered are presented in canned reports lacking connection to the original data, which prevents further data analysis and extended reporting. The approach presented in this paper attempts to overcome such barriers by performing openpit optimization through databases. An adaptation of the Lerchs Grossmann graph algorithm is used to generate nodes, arcs and tree structures in customized tables to determine the maximum closure of a graph.

Nov 1, 2013

By Matthew Deutsch

A common casualty of modern openpit mine optimization is the assurance that the resulting design is actually achievable. Optimized mine plans that consider value and a bare minimum of precedence constraints do not, in general, translate into practical, operational mine designs that can be used in the field. Ultimate pits may come to a sharp point at the bottom. Schedules may require taking small parcels of material from many disparate areas of the pit in a single period, and grade control polygons may be ragged, narrow and not minable with realistic equipment. In this paper, these three fundamental openpit mine optimization problems are addressed by encoding them as maximum satisfiability problems. Maximum satisfiability provides a useful framework for problems that are nonlinear and may guarantee the optimality that metaheuristics cannot.

By Ralph P. Hackl

Ore at the Congress gold property, located near Goldbridge, British Columbia, is extremely refractory with most of the gold disseminated in fine-grained arsenopyrite. Metallurgical testwork conducted by Giant Bay Biotech Inc. indicated that biooxidation pretreatment was capable of increasing cyanide gold recovery from the ore to greater than 90%. To determine if the bioleach process could be successfully scaled up, a 225m' (7950-cu ft) commercial size bioleach reactor was built and tested at the mine site in 1989. At that time, the tank was the largest bioleach reactor ever operated. The objectives of the program were: • to ascertain if the biooxidation rates obtained in lab and pilot-scale reactors could be duplicated in a commercial scale tank; • to identify agitation conditions under which the process will function optimally; and • to demonstrate the bioleach process on a scale sufficient to satisfy the owners and potential investors.

Jan 1, 1990

By T. M. Storer

Much has been written and many discussions held on the virtues (and evils?) of a Company-owned motor fleet. Almost invariably these dialogues take a generalized form and thereby lose something since the individual circumstances, geography and philosophy - particularly in diverse industries, is never quite the same. In considering the nature of my remarks today, I felt a departure from the general approach might be in order, and in lieu of that, will attempt to present a concise picture of how we in the Lehigh Portland Cement Company view this problem and the steps we have taken in our efforts to solve it. At the outset a word may be in order about the Lehigh Company itself, what we do, and the problems that confront us specifically as well as the cement industry at large. We are primarily a manufacturer of portland cement operating 10 plants with a total annual capacity of about 23,000,000 barrels. We market this material in 30 states, shipping both from the plants directly as well as through a system of 18 distribution terminals. About 150,000 truckloads of cement are shipped to customers each year.

Jan 1, 1969

By A. S. Speirs

Over the last few years, the never-ending search for mineral wealth has taken the exploration efforts of Canadian mining companies further and further into the High Arctic and isolated locations where regularly scheduled transportation and communication facilities are nonexistent. Names such as Black Angel, Nanisivik, Asbestos Hill, New Quebec Raglan, Rabbit Lake, and Arvik are today frequently mentioned in mining publications. Twenty years ago, mining in these locations was unheard of, mainly due to logistic problems. However, improvements in the design and use of helicopters, STOL aircraft, and icebreakers in northern areas have helped to overcome these problems, making these locations more attractive to mining companies. Since 1969, when Redpath completed its first Arctic project at Texas Gulf's Scrathcona Sound property on the northern tip of Baffin Island, Redpath has been actively involved in contracting and engineering projects in three general areas: the High Arctic, Ungava and Greenland. A map showing some of these projects is shown in Figure 1. In these areas, permafrost conditions exist from a depth of 274 metres in Ungava to a depth of approximately 610 metres in the Little Cornwallis Island area, with rock temperatures ranging from -5°C to -13°C. Outside temperatures range from a low of -50°C in the winter to a high of 21°C in the summer. High winds in the winter result in wind chill factors lower than -73°C

Jan 1, 1980

By Michael Li, Kathryn Rogers, Arie Moerman, Mike Cooper

The Brunswick Mine, a Division of Noranda Inc., produces zinc, lead, copper, and bulk lead-zinc concentrates through underground mining of a large massive sulphide deposit. The mining method employed is longhole open stoping with delayed backfilling. In 1996 Brunswick began a review of its mining methods and backfilling operations. In 1997 the decision was made to convert the backfill system from cemented and uncemented rockfill to paste backfill prepared from mill tailings. This paper will describe the features of the backfill preparation and distribution systems, review the handling of technical issues, and discuss experiences since plant commissioning.

Jan 1, 2001

By Samuel A. Rasmussen

Lead anodes are used in commercial copper electrowinning operations, yet there is no method to calculate anode life. To be discussed in this paper are operating characteristics of rolled plate (Pb,Sn,Ca) alloy anodes at Morenci's electrowinning tankhouse along with fundamental operating conditions and how the anode reacts to these conditions. These include anode maintenance, electrolyte temperature and viscosity, cobalt concentration, and manganese concentration. Also to be discussed are anode substrate characteristics under normal operating conditions and how the corrosion rate is affected by changes in operating conditions.

Jan 1, 1995

By Richard B. Jacob

The High Gradient Magnetic Separator (HGMS), also known as the High Gradient Magnetic Filter (HGMF), is an effective device utilized in magnetic separation. This method of separation is gaining popularity in the separation of sub-micron material containing feebly magnetics. The most common use of this type of separator is in the removal of iron stained particles to improve the brightness of kaolin clay. Potential areas for use of this magnet include: (1) desulfurization of coal (2) the clean-up of mill effluent (3) removal of fine particulate matter from municipal and industrial waste (4) desulfurization of oil

Jan 1, 1983

By Thomas J. Kingston

A general overview of the taconite crushing process at Minntac is presented The process is controlled from a central control where the control room operator uses closed circuit TV, computer process control and alarms, graphic panels, and radio communication to roving attendants to run the Plant. This paper points out the operating controls and parameters as the plant operator sees and uses them.

Jan 1, 1980

By Richard V. Good, John B. Harvey, Lloyd S. Jones

INTRODUCTION The term "Rapid Underground Excavation" is generally associated with high speed tunnel advance with large volumes of excavation, and indeed this is the type of work for which most of the recent innovations in methods and new machinery have been developed. However, the term applies as well to any underground excavation process that results in an earlier project completion than would be expected with conventional methods, and hopefully with a decrease in total unit excavation cost. Often significant progress has been made during the primary stages of an underground construction project and then an inordinate amount of time and effort has been expended on small units of "miscellaneous" excavation which has delayed the overall project completion and escallated overall unit costs. Construction at the Nevada Test Site of the Atomic Energy Commission for underground testing frequently requires significant amounts of so called "miscellaneous mining" such as short access drifts, cross cuts, alcoves, niches and concrete keyways. Many of the keyways must be excavated without disturbing the rock beyond the excavation lines and construction scheduling often dictates that much of the work must be accomplished without disturbing sensitive electronic equipment already installed. In order to cut down on lengthy and costly delays required for the tedious manual excavation of much of this miscellaneous mining, a market search was made for suitable mechanical excavation equip-

Jan 1, 1997