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By Scott A. Crozier

Environmental regulation of the United States copper industry has evolved significantly over the past three decades and the pace of that evolution is expected to escalate dramatically during the 1990's. The paper examines, from a corporate perspective, current environmental regulation and expected trends including the development of Subtitle D regulations for mineral extraction, beneficiation and processing activities under the Resource Conservation and Recovery Act. The paper concludes by exploring existing and potential impacts on copper companies in complying with the changing environmental regulatory scheme and responsible and progressive precautionary measures companies should consider to address these issues while simultaneously addressing often competing socioeconomic demands.

Jan 1, 1992

By J. J. Lewis

In the mid-1970's a major new prospect was proved in a previously unworked region of North East Leicester- shire, United Kingdom. Preliminary estimates from borehole information showed over 500 million tonnes of recoverable reserves. A special Planning Team was set up, to co-ordinate the work for the two local Areas, South Nottinghamshire and South Midlands (management of production of the UK National Coal Board is organised in twelve such Areas). The team was led by one of the authors as Deputy Director, Mining, North East Leicestershire Prospect (NELP). The remit imposed by the National Coal Board was to analyse the possible options of number, location and eventual rates of output of shaft or drift access; to select a recommended alternative in the light of geological, mining, topographical and environmental considerations; and prepare submissions in accordance with standard Board practice on major projects - such submissions including detailed engineering design, financial appraisal, and full risk assessment. To assist the Planning Team, surface and underground consult- ant engineers were appointed to prepare feasibility studies of specific civil and engineering problems.

Jan 1, 1979

By Ken J. Richards

Industries dependent on pyrometallurgical processing generally find themselves facing a common set of problems, namely, serious environmental restrictions, heavy capital requirements for new facilities and for plant modernization, the certainty of rapidly escalating fuel costs, and the uncertainty of fuel availability. To remain competitive, it has become clear to industry that a new dimension of attention must be given to assuring the maximum performance from plant facilities already in place and from those that are built in the future. In the last decade or so, in response to these needs, there has been an acceleration in the development of new pyrometallurgical process concepts. Their application, though spotty, is increasing. A common factor in this developing base of technology is the need for effective process control. Digital control is an indispensable element of meeting the challenge. We cannot make the point, however, by looking to a general survey of instrumental control of pyrometallurgical processes. Computer control is in its awkward adolescence. Its application is so new that only isolated applications can highlight the trends. For this reason, the authors have chosen to focus on the nonferrous smelting industry to illustrate the status of pyrometallurgical processing and control. We believe this approach will best meet the interests of most readers of this edition and the background of the authors.

Jan 1, 1979

By J. A. Siekmeier

The thickness of the laminated beam modeled in this study is based on bridging potential and TDR measurements. The laminated beam stiffness is based on the effective stiffness of an equivalent transformed section. The maximum deflection of this near-surface laminated beam is compared with the maximum measured surface subsidence. The spreadsheet provides a rational technique to graphically display the character of the overburden and potentially allows prediction of a subsidence factor based on boring logs and the proposed mine plan. The U.S. Department of the Interior, Bureau of Mines (Bureau), utilizes a commercially available computer spreadsheet program in combination with a modified version of Bieniawski's Rock Mass Rating (RMR) system to characterize the geology overlying high extraction coal mines. The spreadsheet program calculates a RMR for each bed based on the lithology, thickness, and engineering properties, which are determined from boring logs and laboratory tests. Once the RMR is calculated the spreadsheet has two major functions. First, the spreadsheet calculates values used to graphically represent the character of each individual bed in the overburden. It calculates an in situ deformation modulus using an empirical rela¬tionship between the modulus and the RMR and then uses this effective modulus along with additional parameters that are based on mine geometry to calculate the bending stiffness and bridging potential for each bed. Second, the spreadsheet creates a transformed section that allows groups of beds to be modeled as an elastic beam. It then calculates a bridging potential for the entire rock mass. The bridging potential of the rock mass is a single value that takes into account both the geology of the overburden and the geometry of the mine. It seems reasonable that there would be a strong correlation between the bridging potential, the overburden response to high extraction mining, and the subsidence ratio. The results presented in this paper focus on the relationship between the bridging potential of individual beds and the deformation measured using Time Domain Reflectometry (TOR). Subsurface displacements measured over seven high extraction coal mines in southern Illinois were correlated with the bed stiffness and bridging potential profiles. Based on these correlations it was evident that the process of caving and subsidence over these high extraction mines involved momentary bridging by individual beds or groups of beds and the ultimate development of a laminated beam near the surface.

Jan 1, 1986

By James E. Kolesar

An essential prerequisite to expanding the application of longwall mining techniques in the United States is the development of a better understanding of the mechanics of rock mass deformation near the mined seam, in the inter- burden and at the surface. The results of studies of this type will provide a basis for the development of empirical and/or numerical modeling techniques to predict the rock mass response to mining both near and far from the mined seam. This will lead to improved gate and panel design, resulting in maximum recovery, increased productivity, as well as provide a mechanism for assessing likely surface effects induced by long- wall mining. Presented here is the instrument plan to be used at Kitt Mine No. 1 in the study of rock mass response to two adjacent longwall panels.

Jan 1, 1982

A Mark IV surface force apparatus (SFA) was used to conduct direct force measurements between mica surfaces in dodecylamine hydrogen chloride collector solutions at varying pH levels. It was found that long-range hydrophobic forces reach a maximum at pH 9.5, which also corresponds to the maxima attained by the contact angle and flotation recovery of quartz. The charge densities are comparable on both mica and quartz surfaces (0.40 to 0.48 nm2), making it possible to draw conclusions on the flotation of quartz from the direct force measurements conducted on mica. Therefore, it may be suggested that, in the pH range of 8.0 to 10.3, the maximum flotation recovery of quartz may be attributed to the appearance of a long-range hydrophobic force, which, in turn, can be related to the formation of a close-packed monolayer (or hemimicelle) in the presence of neutral amines formed as a result of hydrolysis.

Jan 1, 1998

By F. F. Peng, Y. Xia

In modeling of hindered-settling bed separators, the published separation mechanisms are based on differences of particle density and size distributions, without the details of complexity of particles-liquid interactions. A fluid dynamic model for the separator is developed using Euler-Lagrange approach of Computational Fluid Dynamics (CFD). Fluid motion is obtained from solving the movement of liquid governing equations. The damping effect on flow pat-terns caused by the movement of particles resulted in liquid-particle coupling is included in the model. Effects of particle size, and particle density compositions, feed rate, feed water flow rate, upward fluidizing water flow rate, etc., are simulated in the 2-D separation model. Flow pattern effects on the separation of fine particles in the separators with center downward-flow and side cross-flow feed systems are investigated.

Jan 1, 2004

Tables

Jan 1, 1973

By Charles T. Ford

Limestone neutralization of acid mine drainage has been proposed and examined as a method of treatment. However, limestones differ greatly in composition and structure. The reactivity of 14 selected limestones was studied, both by chemical and physical properties and by relative effectiveness in neutralizing synthetic and actual mine waters, and several guidelines for the choice of limestones are given. The particle size should be at least as small as 74 microns and preferably smaller. The most effective limestones are most nearly pure calcium carbonate. Stones which have a relatively low calcium con- tent but which contain calcite and have a large surface area are also effective neutralizers. Magnesite and dolomitic limestones are much less reactive. Disadvantages in using even the most reactive lime- stones for neutralization are indicated.

Jan 1, 1974

I am deeply honored and grateful to receive the prestigious Gaudin Award. Frankly, I find myself amazed to be included in the company of those outstanding individuals who have previously received this recognition. I am humbly honored to receive this award from an industrial research group. Gaudin was an internationally respected leader of mineral processing. His research contributions widely covered the whole spectrum of mineral processing science and technology, including comminution, size distribution, electrostatics, magnetics, thickening and, especially, the development of flotation theory and application. In his later career, he increased his emphasis on hydrometallurgical technology. In fact, one of his most notable practical contributions was in the development of leaching and ion exchange purification of uranium from low-grade ores. Gaudin catalyzed the trend in mineral processing toward engineering science for a better understanding of process mechanisms and kinetics. He said that those working in academic fields should have an underlying responsibility to the industry they represent. This imposed on him the objective of seeking out research areas that had some relevance to industry's problems. He said, "research without an audience cannot survive." Gaudin performed a most vital service, both in the areas of research in which he was actively involved and through his less-direct influence on current research by his many former students and their students in turn. Interestingly, Gaudin's strength has influenced Newmont Mining Corp. His favorite student was Plato Malozemoff. He had a long and distinguished career with Newmont, beginning as staff engineer in 1945, serving as Newmont's president for more than 30 years and as chairman of the company for 20 years. Newmont's greatest growth occurred during his leadership. Another one of Gaudin's graduate students from Montana School of Mines, Oscar F. Tangel, joined Newmont in 1967. He was a vice president of research and development until 1986. In their efforts, Newmont built a research group, developing the technologies of exploration, geophysics and metallurgy. The Newmont technical facility is named in honor of Malozamoff as "a leader in the development and implementation of new technologies." The mining industry is facing very difficult times, especially in the metals industry. Most metal prices have declined and are still not stable. Most domestic mining companies have largely done away with in-house research and development. Many are reluctant to invest in technology development for which there is not an immediate need. The metal mining industries are focusing on reducing operating costs to survive. Newmont is in the same situation. I appreciate that Newmont's management believes in the importance of research and technology and the impact technology has on the company's value. At Newmont, technology development involves working in the area of applied research. The connections from academic fundamental research to applied research and finally to process development and implementation are very important to develop a new technology. Fundamental research is our foundation, our guidance, giving us direction, providing the principal and mechanism and understanding why it works. Understanding the why will lead to further innovative development. Applied research needs to find the approach to reality, how it works, how to make it better and how to commercialize it. Process development and implementation needs a strong leadership, requires long-term commitment, makes improvements in practical engineering and finally develops an economically favorable process. Implementation is the most important stage in making research a reality. Each stage needs to give feedback to the other stages. Problems need to be understood and solved. Otherwise, the new technology will go nowhere. Simplicity of operation is a key of success in any plant. Necessity is the

Jan 1, 2002

By S. P. Mehrotra

In this review article, various approaches and mathematical models that have been used to simulate, design, and synthesize flotation circuits are examined. First, a brief review of flotation kinetics is presented which is followed by a discussion on simulation of flotation circuits. The existing literature on optimal design of flotation circuits has been divided into two broad categories. In the first category, a generalized integral approach is used wherein the optimal circuit design involves determination of both optimal interconnection of various flotation cells/ banks of cells in terms of structural parameters and optimal values of various operating parameters. In the second category, a conventional circuit configuration is assumed to be the best configuration; the optimal design here only means the optimization of operating parameters. The merits and demerits of these two approaches are discussed.

Jan 1, 1987

By E. Lefeuvre

Precambien in age, the phospate deposit under study which outcrops to the south forms a synclinal consisting of only one mineralized horizon. The synclinal strikes SSW/NNE, dips from 30 to 60 NNE and is about 5 km wide. The deposit has been explored by : - trenches and pits about 50 m apart in the outcropping area ; - core drill holes forming lines perpendicular to the outcrop. These lines are about 100 m apart. On each line, the drill holes are about 50 m apart The phosphate layer is clearly visible and has then been defined from the geologicia1 description of drill hole logs. The layer has been divided into two parts : a very rich, altered part at the hanging wall and a poor part displaying opposite physical characteristics, i.e. a fresh and hard rock. With open pit mining in view, the deposit has been divided into a 3-dimension network of blocks, each block measuring 50 X 50 X 100 m. The tonnages of rich and poor ore, PO25, MgO, Si02, CaO and R2O3 grades and the tonnages of barren waste at the hanging wall and the footwall have been calculated for each block. Given the dip of the phosphate layer ranging from 30 to 60° and its relative thickness (between 10 and 15 m), it was impossible or inappropriate to carry out direct calculation by 3-dimension kriging : too many neighboring blocks to obtain sufficient date and impossibility to draw up the morphology of the layer.

Jan 1, 1986

By d&apos, L. R. Fletcher, Andrea. D. V., M. A. Peltier

The Bureau of Mines analyzed coal mine blasting accident data obtained from the Mine Safety and Health Administration (MSHA), U.S. Department of Labor. The data were examined to determine the causes, frequency, and severity of accidents in an effort to point out the most dangerous aspects of coal mine blasting. Accident data for the 14 years from 1971 through 1984 show that there has been a total of 43 fatal and 926 nonfatal blasting accident victims in surface and under- ground coal mining. This is an average of 3.1 fatal and 66.1 non- fatal injuries each year. Underground coal mining accounted for 60.5% of the fatal and 78.7% of the nonfatal accidents involving explosives and breaking agents in coal mining. In addition, since 1970 there have been 53 fatal and 20 nonfatal injuries that occurred when explosives were the ignition source for dust and/or methane explosions in underground mines. Abstracts from 297 accidents that occurred from 1978 through 1984 were also examined to determine accident causes. Most accidents occur during scheduled blasting, and failure of the blast area security system is the leading cause. Blast area security problems in surface mining are failure to clear the blast zone, failure of personnel to follow instructions, inadequate guarding, and failure to retreat to a safe location and/or take adequate cover. Other common causes in surface mining include premature blasts, excessive flyrock, and misfires. In addition to the above causes, accidents in underground coal mining can be due to rockfalls triggered by the blast, unexpected breakthroughs, fumes, and incidents associated with Airdox-type systems.

Jan 1, 1986

By A. Wright

Gold Fields Mining Corporation is presently evaluating gold mineralization beneath thick, wet alluvium at the Chimney Creek Project, Nevada. Contamination of reverse circulation samples has been visually apparent since drilling began in the area. Tests have shown that, while contamination can affect assays, reverse circulation holes appear to define mineralized zones almost as well as the diamond drill holes. To improve reverse circulation sample integrity several techniques were tried including a stiff-mud injection system but with limited success. Diamond core drilling continues to be used in conjunction with reverse circulation drilling to further delineate the mineralization.

Jan 1, 1991

By Z. Rogovin

A Knowledge of the amount of time the material spends in a continuous mill in a closed-grinding-circuit is essential for circuit performance analysis and scale-up design. A convenient method for acquiring this information involves the use of tracers in residence-time-distribution (RTD) experiments. In a typical wet process the RTD measurements are usually done by injecting a pulse tracer into the mill inlet and detecting it in the circuit exit. In this article a simple to use mathematical method for the calculation of the closed circuit material residence time in the mill is developed. Using this method there are no restrictions on the location of the tracer injection or detection points. Any convenient location in the closed circuit can be chosen without affecting the simplicity of the method. This method also enables the calculation of the degree of mixing in the mill. The use of this method for the analysis of impulse response data obtained from several commercial grinding circuits is presented.

Jan 1, 1986

By B. Mishra, A. Staley, D. Kirkpatrick

The major waste product of the alkaline extraction of alumina from bauxite (Bayer Process) is known as red mud. Approximately one ton of red mud is produced for every two tons of bauxite mined. The red mud produced from Jamaican bauxite is rich in hematite, alumina and titanium oxide. It has been shown that more than 90% (by weight) alumina can be recovered from red mud by soda ash sintering and caustic leaching. Hematite can be carbothermically reduced with a degree of metallization of more than 94%, resulting in attempts, for magnetic separation. These separations are desirable because there are no waste products generated. Consequently, there is an opportunity for complete utilization of the waste material. Conversely, the preseparated material could be charged through the tuyeres in an iron blast furnace, or it could be smelted to produce pig iron. If smelted, the concentration of titanium oxide in the slag would be high enough to justify its recovery by an established acid-leach process. This paper describes the results of alumina recovery and the plans for titanium oxide recovery from red-mud. In addition, the situation of ongoing efforts in iron extraction, particularly, the method of magnetic separation of the reduced material. The problems associated with the use of reduced red mud as an alternative to direct-reduced iron (DRI) is also discussed. A critical assessment of the recovery sequence chosen for the products is described based on economics. Key words: Red mud, Waste product utilization, Alumina recovery, Titanium oxide, Iron

Jan 1, 2003

By John E. Tilton

Mining is one of the oldest human activities. It goes back at least to the Bronze Age and possibly even the Stone Age. The Romans mined copper in Spain and tin in England some 2,000 years ago. The writings of Agricola in the 16th century show that mining was important in the Middle Ages. Today, more mineral commodities are mined in greater tonnages than ever before. This long and fascinating history closely tied with the economic development of the human race is one of the charms of the mining industry. It also, unfortunately, gives rise to some widespread misconceptions. Old industries are generally considered stodgy with mature and stagnant technologies. Costs tend not to decline as in newer industries, and may even increase with real wages. Costs are particularly expected to rise in the case of mining as the best mineral deposits are depleted. Thus, mining is often thought of as a sunset industry, destined to decline over time as the resource base is depleted. These perceptions have several important implications. They argue against economic policies that rely too heavily on mining and mineral processing to foster growth and development. The best and the brightest young people, along with society's other valuable resources, should be encouraged to enter newer industries. There the technological opportunities and the prospects for growth are more promising. These perceptions also suggest that the ability to compete in the mining industry depends largely on the quality of a company's or country's mineral deposits. Mining will take place first in countries with the lowest-cost deposits. Once these are exhausted, mining will shift to countries with the next best deposits. From time to time, new discoveries may also produce a shift in the location of mining, [ ] and may even for a time keep the costs and prices of mineral products from rising. Over the longer term, however, rising costs and prices are inevitable, as the world is forced to exploit poorer mineral deposits.

Jan 1, 1997

By Peter Ralph

All copper ore haulage at Isamine was transferred to the new 19 level haulage network by mid 1975. Previous experience together with design studies had indicated that a three train operation would be required to haul the scheduled ore production. The ore train with a gross weight of 600 tonne is made up of 15 bottom dumping trucks hauled by twin electric locomotives (Figure 1). Present train speeds reach 40 km/hr and, in the future, this speed could be increased to 55 km/hr. The planned operation on the restricted track network and the relatively high train speed meant that the train driver operated block light system would be inadequate on the grounds of haulage safety and meeting production targets. Some form of Centralised Train Control (CTC) system emerged as a necessity, and as an initial step, tenders were called for a relay control type CTC system. The high cost of these systems and the anticipated high maintenance costs and inflexibility of the offered systems led to the rejection of the tenders. It was decided to develop a CTC system locally and to use a digital computer to perform the basic track [ ] equipment interlocking tasks and monitor haulage operation.

Jan 1, 1979

By Hans Hamrin, Bruce Kennedy

Once an ore body has been probed and outlined, and sufficient information has been collected to warrant further analysis, the important process of selecting the most appropriate method or methods for mining can begin. At this stage, the selection is preliminary only, serving as the basis for a project layout and feasibility study. Later, it may be found necessary to revise the details, but the basic principles for the ore extraction should remain a part of the final layout. With respect to the basic principles employed, relatively few mining methods are used today. For the purposes of this presentation, the principles are classified as follows: 1) For naturally supported stopes, the available methods are room-and-pillar mining and sublevel stoping. 2) For artificially supported stopes, the available methods are shrinkage stoping, cut-and-fill mining, square-set mining, and longwall mining. 3) For caving methods, the available techniques are sublevel caving and block caving. Due to the uniqueness of each ore deposit, the variations on each of these methods are nearly limitless. It is impossible to include even the major variations in this chapter; the goal of this chapter is to present the principles as a guide to the mining engineer in adapting the general methods to specific needs. The selection process described herein is intended to supply the techniques by which the candidate methods available for a given ore body can be reduced to one or two feasible approaches. The feasible approaches then can be evaluated in detail, and the particular modifications can be investigated. In describing costs and economic factors, all values herein are expressed in terms of 1978 US dollars.

Jan 1, 1982

By Paul L. Boni

Trona, Na3(CO3)(HCO3) ? 2H20, is mined in quantity from saline facies of the Eocene Green River Formation of southwestern Wyoming. The Green River deposits are the world's largest known resource of natural sodium carbonates. An estimated 127 billion tons of trona ore are known to occur in beds exceeding 4 ft in thickness (Wiig and others, 1995). Twenty-five trona beds, exceeding 3 ft in thickness, and covering at least 100 mil have been identified. The beds are numbered sequentially in ascending stratigraphic order. Trona beds underlie more than 850 mil (bed 17) and are up to 37 ft thick (bed 1) (Culbertson, 1966). Five underground mines, operating in beds 17, 19, 20, 24, and 25, process trona to produce soda ash (sodium carbonate). A total of 11,837,703 short tons of soda ash were produced from 17.1 million tons of trona ore in 1997 (Kostick and Clark, 1998). A detailed study of trona bed 17, using techniques of petrography and X-ray diffraction, has been undertaken in the Solvay trona mine, near Green River, Wyoming. A continuous, vertical-channel sample was taken from near the production shaft for this study. At this location, bed 17 is 12.6 ft thick and includes several stratigraphic markers that are easily correlated throughout the mine and in surrounding drill cores. Bed 17 in this area averages 90% trona through its entire thickness (Wiig and others, 1995) and 95-100% trona in the lower two-thirds of the bed. Mineral impurities include water-insoluble dolomite, quartz, pyrite, clays, and other minerals and partially water-soluble northupite and shortite. Northupite, Na3Mg(CO3)2C1, contributes to chloride contamination in the soda-ash product and is concentrated in the upper one-third of bed 17, which is left behind as roof rock. Northupite has two modes of occurrence: (1) as bedded strata with dolomite, chert, clay, and shortite and (2) between primary trona crystals in trona spar. Petrographic and mineralogic data indicate that this section of bed 17 was deposited subaqueously during its early and late history and may have undergone periods of deposition in a subaerial or marshy environment. Stratigraphic data indicate that trona accumulated at an annual rate of 2-4 in. per year. During trona deposition, dolomite, CaMg(C03)2, precipitated in parting layers when new water entered the lake, freshening supplies of calcium and magnesium. The lack of clay minerals in the trona facies suggests water input may be by means of springs, as opposed to overland flow. Clay occurrences in thicker dolomitic partings within the trona facies indicate periods of episodic overland flow, possibly resulting from storms in the surrounding basin.

Jan 1, 1999