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By David E. Lindorff

The impact of surface coal mining on the geologic materials and ground water in different geologic settings is being investigated by the Illinois State. Geological Survey at three abandoned surface mines in Illinois. At a site near Ottawa in La Salle County, the overburden prior to mining consisted largely of pyritic shale; sand was the major component of the overburden and spoil at a mine near Coal City, Grundy County. Clays, lacustrine silts, and some shale and limestone were the dominant premining overburden materials at a mine near Harrisburg, in Saline County. Ground-water elevations at Coal City and Harrisburg are approximately at premining levels, whereas at Ottawa they are near the base of the spoil. Ground-water quality has deteriorated at all three sites, especially at Ottawa and Harrisburg.

Jan 1, 1981

By Y. C. Kim, M Nataraja, J. T. Buckley, D. H. Tiktinsk

The Nuclear Waste Policy Act of 1982 (NWPA) assigns the U.S. Department of Energy (DOE) the responsibi1it.y of locating, constructing. operating, closing and decommissioning a nuclear waste repository. Prior to submittal of a licensee application to the U. S. Nuclear Regulatory Commission, the DOE is required by 10 CFR part 60 to conduct a program of site characterization for the site to be described in such application. Site characterization includes an exploration and research program in the field and laboratory to determine the geologic conditions and ranges of those parameters which are necessary for determining the suitabi1it.y of the site as a geologic repository. The information thus collected should be able to establish with reasonable assurance that the public and environment will be adequately protected from the hazards associated with a repository at the site. This paper demonstrates by example a geostatistical approach which, on the basis of the existing limited data base, can be used to evaluate (1) whether existing information on a certain parameter is adequate to be considered representative. (2) if additional information is required, where should the additional sampling or testing be performed, and (3) whether the new1.y acquired data along with the existing information constitute representative data.

Jan 1, 1986

By M. Karmis

"The process of coal mining, as indeed of the mining of any stratified mineral, is inevitably followed by some degree of sinking of the superjacent strata and consequently of the surface." Royal Commission on Mining Subsidence, Second and Final Report, London, 1927. INTRODUCTION The above statement was used to describe mining subsidence in the classic report of the "Royal Commission on Mining Subsidence," published in 1927. In fact, this phenomenon has been recognized in Britain since the early fifteenth century, as revealed from court records of disputes and litigations related to property damage above mine workings (Shadbolt, 1978). The first attempts to investigate and analyze the mechanisms associated with mining subsidence, however, date back to the 1800's and were pursued by Belgian Engineers. This research effort was initiated as a result of the widespread movements and subsequent structural damage suffered by the City of Liege in the 1820's. The most notable achievement of the Belgian school of that era was he publication of Gonot's treatise "Loie de la Normal" in 1871 (Gongt, 1871).

Jan 1, 1982

By J. C. Watts

Ball mill grinding circuit control has received increasing emphasis in the past few years due to such factors as declining ore grades, increasing production costs, and advances in analytical devices and minicomputer technology. Since ball mill circuits have been a traditional bottleneck in mineral processing plant throughput, control systems often improve through- put without requiring additional processing equipment. In addition, much of the variability of the grinding product size and consistency is often removed, allowing better process operation downstream. Among the problems which arise in designing and implementing a process control strategy for ball mill circuits are circuit constraints imposed by processing equipment and local management, proper instrument selection, installation and maintenance, and use of calculated or inferred variables for process measurements. This paper discusses these problems and attempts to identify valid approaches to their solution.

Jan 1, 1979

By Diler Katircioglu-Bayel

The effects of the operating parameters of media filling ratio, solid mass fraction, grinding media size and grinding time on the stirred media milling of talc were studied. The findings were assessed based on the product particle size (d50, d10), surface area (Sw) and energy consumption (Em). Furthermore, after determining the optimum grinding conditions, Box-Behnken statistical design was used to determine the effect of parameter interactions on the d50 size. The media filling ratio significantly affects d50 size decrease compared with solid mass fraction and grinding time. The minimum d50 size was also achieved under optimum grinding conditions.

By Richard P. Killmeyer, Carl P. Maronde, W. W. Wen, Peter J. Suardini

Under a cost-shared Department of Energy contract, awarded as part of the Coal Preparation Program&apos;s High Efficiency Preparation subprogram, Custom Coals International will be installing and testing a 227 kglhr micronized-magnetite cycloning circuit in PETC&apos;s Coal Preparation Process Research Facility. The project includes the design, construction, testing, and decommissioning of a fully integrated circuit complete with feed coal classification to remove the minus-30-micron material, dense-medium cycloning of the 300 by 30 micron feed coal using micronized magnetite (<10 microns), and medium recovery via drain & rinse screening and various stages and types of magnetic separation. This paper will describe the micronized-magnetite beneficiation technology and the scope of work for this project including an update on the status of the project, the circuit, and the proposed test plan.

Jan 1, 1995

By David A. Milligan

This paper describes the Darwin Silver Recovery project, located 66 km (40 miles) outside of Lone Pine, near Darwin, Inyo County, California. A lead-zinc mine and a flotation concentrator were operated there from 1945 to 1957. By the time the mine was shut down, 1.53 Tg (1.69 million short tons) of tailings had been stored in ponds. An average silver assay of 47 mg/kg (1.38 troy oz/st) of tailings stimulated interest for commercial silver recovery. A heap leach process was developed in 1981 at the Tucson Research Center of Anaconda Minerals Company, a division of Atlantic Richfield Company. Agglomeration techniques were used on the ore since the fine grind did not allow direct heap leaching. Lime and cement were required as binders, Early laboratory tests showed that recoveries equal to those from an agitated leach could be achieved at lower capital and operating costs. Laboratory tests determined cyanide requirements, lime and cement usages, and percolation or leach rates, as well as confirming that a zinc precipitation step could recover the silver from the leach solution.

Jan 1, 1983

By Lei Pan, Venkata Atluri, Xuming Wang, Yuesheng Gao, Jan D. Miller

Polysaccharides have been used as depressants for naturally hydrophobic talc in the flotation of base metal sulfide ores, precious metal sulfide ores and platinum group metal (PGM) sulfide ores. The results of this surface chemistry study confirm guar gum as a preferred polysaccharide for talc depression in the flotation of these ores. In addition to the practical application of the research results, the surface chemistry results are of academic significance, providing further information to understand how polysaccharide depressants function in these complex sulfide flotation systems.

By E. J. Beckman, R. M. Enick, C. Shi

A novel liquid-liquid separation for the recovery of free or liberated gold from mixtures of fine particles was evaluated. Two inexpensive and environmentally benign fluids were selected for the study, water and carbon dioxide. The separation, which is conducted at 295 K and at the vapor pressure of carbon dioxide (6.0 MPa), is based on differences in wettability between the precious metals and other minerals. Contact-angle results indicated that, in the presence of water and liquid CO2, gold is slightly hydrophobic. The addition of CO2-soluble fluoroalkyl thiols or f uoroetherthiols increased the hydrophobicity of gold exposed to water and CO2 to a greater extent than alkylthiols. Minerals, including quartz, pyrite and magnetite, were hydrophilic. During the separation, an aqueous slurry of fine mineral and gold particles was mixed with liquid carbon dioxide. Pure gold particles (-325 mesh) were found to agglomerate at the H2O-CO2 interface. The minerals tended to remain in the aqueous phase. Despite these promising preliminary results, very poor gold recoveries were obtained when applying the procedure to an Australian gravity concentrate. This was attributed to the native gold particles in the concentrate being either too large, agglomerated in slimes or coated with minerals. Although this particular application was unsuccessful, this water-CO2 biphase technique may be applicable for other separations that require the removal of very fine, hydrophobic particles from an aqueous slurry.

Jan 1, 2000

By M. A. Trevits, G. Frampton

"Mine safety training materials have long included pictures of mine conditions, equipment, hazards, etc. These images are invaluable to both the trainee and the trainer to convey many important concepts. The human eye takes in a tremendous amount of information, while the field-of-view from a consumer grade camera is, generally, 40 degrees to 90-degrees. This difference in field-of-view is a primary reason that pictures, especially of dark and dusty areas, don’t adequately describe the scene. For conveying information to a trainee, these images lack context. Today, 360-degree cameras are available with consumer-grade cameras costing a few hundred dollars. Also, the display technology is already owned by most trainees and trainers and is widely available. The resulting 360-degree videos and pictures can be readily viewed on smart phones and inserted into Microsoft PowerPoint slideshows. These images and videos can easily be included in existing training modules, disseminated using the internet, and used by trainees easily. We propose a methodology for utilization of 360-degree video and images with simple display technology for miner training. INTRODUCTION AND BACKGROUND In mining, as in other production-related industries, the safety of workers is dependent upon many interrelated factors. One of the more important safety factors is a miner's ability to recognize hazards in their workplace. The ability to perceive and identify hazards is perhaps more difficult to master in underground mining than in general industry because the work environment is confined, noisy, dark, and inherently dangerous because of the hidden unknowns created by the geological setting and the conditions created by the mine opening. Further complicating the situation is a setting that is continuously changing as mining advances (Barrett 1995) [1]. Hours of excellent mine safety training have been developed and utilized over the years. Pictures of mines, activities, hazards, etc., are included in many of these training courses. These photographs, especially those taken underground, often lack context because of the limitations of the cameras and lenses. Notable research by the US Bureau of Mines and then later by NIOSH showed that the use of stereoscopic three-dimensional slides in training exercises was an effective aid for improving the ability of miners to recognize hazardous ground control conditions (Barrett 1988) [2]. An example of type of three-dimensional slides and slide viewer is shown in figure 1."

Jan 1, 2018

By Wilbur I. Duvall

INTRODUCTION This chapter outlines some general principles and procedures that a rock mechanics engineer can use to arrive at a logical design for the size, shape, and spacings of underground openings in various types of com¬petent rock formations. Rock formations can be clas¬sified into six major categories which are useful for design purposes, provided the necessary input data are available regarding the geology of the site, the physical properties of the rock, the in-situ stress field in the rock, and the general geometry of the underground openings. The US Bureau of Mines (USBM) developed a rock classification system based upon these concepts and found it to be useful for design purposes (Obert, et al., 1960; Obert and Duvall, 1967). This classification sys¬tem is given in Table 1; however, an extra column has been added to the original classification to indicate the appropriate design techniques for each rock class. In this classification system, two main classes of rock are considered: competent rock and incompetent rock. Competent Rock Competent rock is any rock which, because of its mechanical and geological characteristics, is capable of sustaining underground openings without the aid of any structural support except that provided by unmined rock in the form of pillars and side walls, etc. Roof bolts and small random props which support only local loose rock are not considered structural supports. Competent rock is further subdivided into three ad¬ditional categories-massive, laminated, and jointed¬ which are defined as follows: Massive Rock: Massive rock is a rock formation where the spacing between mechanical defects such as joints, partings, or faults is equal to or greater than the critical dimensions of openings, or where the strength of the bond across these mechanical defects is com¬parable to the rock strength. Laminated Rock: Laminated rock is a rock forma¬tion divided by approximately parallel planes of weak¬ness into lamina whose thicknesses are small compared to critical dimensions of openings and where the bond between the lamina is weak compared to the rock strength. Elastic Rock-This is rock whose physical proper¬ties will permit the use of elastic theory to predict strains and displacements from applied stresses. Inelastic Rock-This is rock whose physical proper¬ties are such that strains and displacements are a strong function of time as well as applied stress. Incompetent Rock Incompetent rock is any rock which, because of its mechanical and geologic characteristics, is not capable of sustaining underground openings without the aid of additional structural support in the form of linings, steel sets, or systems of props. This classification system for rock depends not only on the mechanical and geologic characteristics of the rock but on the size of openings and their depth be¬low the surface. For example, many competent rocks at shallow depths for small stress fields could become inelastic rock at greater depths and larger stress fields, or competent massive rock for small openings could be¬come laminated or jointed rock for larger openings. Thus, to classify rock for design purposes requires a knowledge of the geologic properties of the rock mass, the physical properties of the rock, the general size of the openings to be mined, and the average range of the in-situ stress field to be encountered. To design underground openings and structures in rock, it is necessary to use criteria of failure for rock under various stress conditions, and to use safety factors to allow for differences between laboratory and in-situ strength properties of rock and to account for errors in¬troduced by the various assumptions made in the design process. Criteria of failure based on maximum stresses have been found to give reliable results in practice. Thus, it is assumed that rock will fail in tension when the tensile stress exceeds the tensile strength of the rock as determined by a standard modulus of rupture test on samples of rock core. If the tensile stresses in rock are small, then it is assumed that the rock will fail at a value of compressive stress equal to the compressive strength of the rock as determined by standard uniaxial compres¬sive strength tests on samples of rock core. These fail¬ure criteria, when used with appropriate safety factors, can be expressed as:

Jan 1, 1982

By H. Weber

This paper is in three parts. Part I discusses the various types of cement clinker coolers now in full-scale operation. Part II is a detailed study of the criteria for selection of the type of cement clinker cooler best suited for a given installation. Part III covers a number of cooling problems and their solutions in some of the metals industries. The large and world-wide problem of cement clinker cooling has motivated much study and development and the coverage here of this work is somewhat detailed. In contrast the cooling problems of the metals industries are quite varied between industries and often quite different from plant to plant in the same industry because of basic differences in the requirements of the particular material being processed. Therefore the coverage of metals industries coolers is somewhat more general. It is believed that all of the technology covered here may be of interest to those working with the problems of cooling hot materials.

Jan 1, 1980

By E. A. Laurila

During last years many different types of X-ray fluorescence analysers have appeared in the market most of these instruments being designed for laboratory use. The instruments applied ins continuous processes are usually modifications of these laboratory types. The application of these instruments to the analysis of heavier elements seems to be quite satisfactory. By lighter elements difficulties are caused by the strong absorption of the characteristic fluorescence radiation, which sometimes makes the use of vacuum or helium chambers necessary. In the following an instrument of another type will be described. It has been developed exclusively for the analysis of titanium in ilmenite concentrate, where the content of Ti02 varies between 43 - 46%. Preliminary measurements have shown that in this interval absolute change of 1% in the Ti02 concentration causes a relative change of about 2% in the intensity. Because: the accuracy of 0.5 % Ti02 is sufficient, 1% relative accuracy should be, attained in intensity measurement. The problem is not very easy to solve due to the fact that Ti K radiation is rather soft and the requirement&apos;s for accuracy are rather high. Being applied to the analysis during a continuous process may statistically fluctuating variables in connection of sampling and disturbances of many kind set special requirements for the instrument design.

Jan 1, 1960

By Otto E. Zwanzig

You may think long before this talk has been completed that the speaker is belaboring the obvious. Please let me put to rest here and now any doubt which you may have in this regard by assuring you that is precisely my intent, and for a very specific reason. We all profess to know and recognize the obvious, but I am impressed increasingly how often we forget or fail to act upon the obvious. Shortly after starting my first job upon graduation from college, I was asked by my boss to participate in a course on practical communications, particularly as applied to conveying proposals effectively to the client -- be he customer or company president. The concept or philosophy underlying this program was so simple and obvious that in my youthful brashness I saw only a gross waste by the company of e good, solid $1930 in compelling me to take the course. The sequel to this experience occurred about five yews ago when I was directing a 300-man marketing group. At that time I enrolled a dozen of my department heads, and subsequently about a hundred other personnel, in the contemporary version of that sane program. Why? -- because they all knew the obvious, but I could see how imperfectly they were implementing it. Truly, a wide chasm exists all too often in our beliefs on the one hand and our practices on the other.

Jan 1, 1962

By Archie W. Fletcher, R. J. Wesely, Nathaniel Arbiter, A. D. Zunkel

In contrast to pyrometallurgy&apos;s six thousand year history in the production of metals, that of hydrometallurgy is of relatively recent origin. The earliest reference to it at all was in the 16th century, with the first applications to copper in the 17th and 18th. In the 19th century, increased demands for pure metal resulted in development of electrolytic refining, and early in this century electrowinning. The rapid growth in wpper production in the present century, paricularly in the United States and Chile, stimulated the development of new technology for leaching, and for the recovery of copper from leach solutions. Solvent extraction has become a major factor during the past quarter century by permitting novel leaching technology which produces dilute or complex solutions. In addition, solvents other than sulphuric acid, and chemical methods for precipitating copper metal are now of increasing interest. These are trends which should grow in importance in the future with the need to process lower grade and more complex materials. The evolution of copper hydrometallurgy is reviewed briefly and key factors in recent major developments are presented with details of specific operations and with trends for the future indicated. The relative importance of copper hydrometallurgy is compared to that of pyrometallurgy in the light of probable changes in ore supplies and character.

Jan 1, 1993

By G. Gregory Bryan

G. GREGORY BRYAN 33.1-DEFINITIONS 1. Engineering-Engineering may be defined simply as the science and art of making materials and energy serve the purposes of mankind. There are many fields of engineering, each with specialized branches. The basic fields are: civil, mechanical, electrical and chemical. Others may be specialized phases of one of these or a combination of two or more of them. Mining engineering, for example, requires a working knowledge of construction, mechanics, electricity, metallurgy, geology, accounting and economics, in addition to mining techniques or methods. Mining geology and geological engineering involve rocks and their structure and the forces that act upon them, and chemistry, physics and mechanics also are important to practitioners in these fields. Metallurgical engineering requires chemistry and physics but also a working knowledge of mechanics and electricity. The fields of engineering with which this section are concerned are those primarily involved in the finding, mining, processing and utilization of the natural mineral resources of the earth. They include geology, mining engineering and metallurgy, each with several specialized subdivisions. 2. The Engineer-The engineer is an individual who has had specialized training to qualify him to practice the profession of engineering. The term engineer is used here in its broadest sense to include such professions as certain applied branches of geology, physics and chemistry, whose practitioners may not have acquired engineering degrees but who, nevertheless, by training and experience in some area of the minerals industry, qualify under the above definition. To become a successful engineer, a person should have certain pronounced aptitudes and preferences, even before embarking upon the requisite course of training. Among the chief qualifications that the engineer-to-he must possess are: (a) a natural inclination toward mathematics and the physical sciences, and (b) intellectual and moral honesty. Among the qualities the student engineer must develop are: (a) independence of thought, open-mindedness, sound judgment and the ability to observe, deduce, plan and apply solutions, (b) the ability to articulate and convince, and (c) the ability to organize and direct the activity of others. These qualities are normally developed through sound education, followed by pro¬gressive experience. 3. The Consulting Engineer-The consulting engineer is an engineer primarily in the business of furnishing specialized advice and engineering services on an intermit¬tent, part-time or occasional basis to clients who do not have continuous or full-time need for those services. He must be able to make and take full responsibility for decisions and recom¬mendations where original thought is required. He should not be confused with the engineer, surveyor or technician who also may furnish services on an intermittent basis, such as regular periodic surveys, the overseeing of drilling programs and other such routine work as may require little original thought and planning. 33.2-THE PROFESSION OF CONSULTING ENGINEERING 33.2.1- QUALITIES REQUIRED A successful consulting engineer must first have, as a minimum, the qualities and preparation of an engineer. In addition, he must have sufficient knowledge,

Jan 1, 1973

By John L. Stauffer, Allan Lipton, Kim Leitzel, Lesley Gaydos, Laurence M. Demers, Douglas C. Kuhn

Eicosanoids and cytokines produced by the alveolar macrophage (AM) are key mediators of pulmonary inflammation and fibrosis resulting from occupational exposure to mineral dust. In order to determine if eicosanoid and cytokine production are altered by chronic inhalation of coal dust, we compared the production of prostaglandin E2 (PGE2), thromboxane A2 (TxA2), leukotriene B4 (LTB4), interleukin 1 (IL-1), tumor necrosis factor (TNF) and platelet-derived growth factor (PDGF) by cultured AM from non-smoking normal human volunteers and coal miners. Inhibitors of eicosanoid biosynthesis were administered to AM from coal miners in order to determine if a link between eicosanoid and cytokine production exists in these cells. Basal PGE2, TxA2, TNF and IL-1 production by AM from active miners was increased compared to AM from normal volunteers. However, the production of these eicosanoids and cytokines by AM from former coal miners was reduced compared to control AM. Administration of the cyclooxygenase inhibitor, suprofen, and the lipoxygenase inhibitor, nordihydroguaiaretic acid, reduced PGE2 and TxA2 production in miners&apos; AM but had no effect on LTB4, IL-1 or PDGF production. Specific inhibition of thromboxane synthase by UK38,485 was associated with a significant reduction in TNF production in active miners&apos; AM but had no effect on PGE2, LTB4 or IL-1 production. The prostacyclin analogue ZK96,480 also specifically inhibited TxA2 production in active miners&apos; AM. The results of these studies suggest that coal dust exposure is associated with alterations in AM eicosanoid and cytokine production which may be relevant to the development of pulmonary inflammation and fibrosis. In addition, the lack of effect of inhibitors of PGE2 biosynthesis on IL1 production in miners&apos; AM suggests the production of these intercellular messengers may not be linked in AM chronically exposed to coal dust.

Jan 1, 1991

By Charles B. Dugger

Sacrificial linings for grinding mills have been a necessary state of the art of mineral dressing since the inception of comminution. Long recognized as the final link in energy transmission from power line to ore, mill liners as a scientific endeavor have not expanded as rapidly as other branches of mineral dressing engineering. Several reasons for this technological lag are apparent. Typically in the past, labor intensive foundries were freely located geographically, at a time when transportation charges made up a significant portion of the casting cost. Alloying agents had not gained their current level of sophistication and were relatively inexpensive in the quantities required. Precise foundry controls were not economically justified, or totally understood. Coincidental to these elements, liner consumption per unit processed did not categorically contribute as a major cost item to the mill operator. Grinding equipment was small, and many times lining life exceeded that of the promoter. These unique conditions no longer exist. Ore dressing equipment has grown to meet modern mining demands. Larger processing facilities, utilizing fewer pieces of equipment, have replaced operations of the past. Emphasis today and tomorrow is on larger and larger equipment, with an eye on lower and lower unit processing costs.

Jan 1, 1979

By T. Ko, K. N. Han, C. S. Park, N. S. Kim, C. Yoon, H. Yoon

Quantitative analysis of Platinum Group Metals from ore samples and industrial materials using Inductively Coupled Plasma-Mass Spectrometer (ICP-MS), Inductively Coupled Plasma-Atomic Emission Spectrometer (ICP-AES), Atomic Absorption Spectrometer(AAS), and X-ray Fluorescence (XRF) techniques was conducted and the performance of various techniques was compared. The effects of different matrices in the sample materials were compared and discussed for each analytical technique. The ICP-AES technique exhibited better accuracy than AAS but showed limitations in its application due to strong spectral interference in the presence of common matrix elements such as iron. The ICP-MS showed the lowest detection limit and less spectral interferences than the previous two techniques. The XRF technique was also applied to examine the total amount of PGM from industrial materials. Results from each analytical method on various sources were presented and discussed.

Jan 1, 2003

By Kimberlie Staheli

A new sanitary sewer was installed in Pleasant Hill, California using microtunnelling methods. The project consisted of 693 meters of 1372 mm and 1981 mm concrete pipe. A Herrenknecht AVN 1200 was used to install the nominal 1372 mm pipe in three drives. The machine was then fitted with an oversized shield used to install the large diameter pipeline. This articulated shield allowed the excavation of a 2362 mm diameter hole with a 1524 mm machine-- a technique new to North America. This paper reviews the design considerations for the articulated shield and reports on the project challenges and solutions to overcome these challenges.

Jan 1, 1995