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By T. McNulty

The author was privileged to find employment as a uranium mill chemist for The Anaconda Company while working his way through school in the mid-1950s. He then served Anaconda in various technical and management positions until 1980. This paper describes the prevalent technologies employed by uranium producers, briefly describes various mines and mills in the U. S., and memorializes a few of the thousands of men and women who contributed to the U. S. Uranium Boom. Following isolation of uranium as an element by M. H. Klaproth in 1789, uses of uranium were confined primarily to pigments, glass coloring agents, and ceramic glazes. In 1896, Antoine Becquerel found that uranium is radioactive, releasing particles and energy as it decays. In 1898, Pierre and Marie Curie isolated radium from uranium and learned that it can be an effective treatment for some types of cancer. In 1939, it was discovered that the isotope U235 is fissionable1 . Up to this point, nearly all uranium production was from pitchblende concentrates made in Bohemia, Canada, and the Belgian Congo. In 1938, only about 5 percent (23.85 short tons) of global output was produced from ores of the carnotite mineral that were being mined in the U.S. By the early-1950s, physicists in many countries had begun to recognize the potential for nuclear chain reactions. Ernest Rutherford (UK), Frederick Soddy (UK), and Leo Szilard (US) explained transmutation of elements and formulated the principle of “atom splitting”. In 1934, Marie Curie’s daughter, Irène, and her husband, Frédéric Joliot, identified uranium as the most viable source for this new form of energy. The basic fission process was unraveled by German scientists in December 1938. After Hitler’s army seized the uranium deposits in Czechoslovakia, many feared that Germany would build the first nuclear weapon.

Mar 2, 2022

By R. C. Bunge

A magnetogravimetric separation is the consequence of two competing forces with opposing directions, i.e., magnetic buoyancy and gravitation (or centrifugal force). While magnetic buoyancy is a function of particle volume, gravitational force depends on particle mass, thus permitting a separation according to specific gravity. Since magnetic buoyancy is not a phenomenon of common knowledge, this chapter is meant to briefly introduce the theory of magnetogravimetric separations. A particle that is suspended in a magnetic fluid which is exposed to an inhomogeneous magnetic field experiences a repulsive force -the so called magnetic buoyancy. In order to illustrate this effect, an analogy with the more familiar hydrostatic buoyancy is drawn. Hydrostatic buoyancy occurs due to unsymmetrical pressure distribution 'above' and 'below' a suspended particle (fig. 1).

Jan 1, 1990

By Lynn B. Hales, Randy A. Ynchausti

Because of the high economic value associated with small improvements in the operating performance of mineral processing plants, innovations in instrumentation, stabilization and expert control systems have been an ever-present part of the landscape in plants throughout the world since the I 960s. Expert control systems are computer programs that continuously monitor plant conditions; contain "expert knowledge" concerning the process, equipment and operational knowledge; and make timely recommendations for new process set points or even directly change the process set points to achieve desired management goals. Early rudimentary expert control systems first appeared in the early 1970s. They have grown from small, experimental but ambitious projects in which single unit operations were controlled to plant-wide systems that include technologies used in the U.S. space shuttle program. Experiences and results of applying these systems throughout the world will be explained discussed and analyzed. Typical results will be outlined and the use of expert control in the future will be projected.

Jan 1, 2000

By A. C. Nixon, A. D. S. Gillies, Hsin Wei Wu

Ventilation and refrigeration strategies for the 3000/3500 orebodies, Mount Isa Mines, Australia were reviewed. The orebodies lie between 1,200 and 1,800 m below surface and are characterised by steep geothermal gradients, intensively mechanised stoping methods and high ambient air temperatures in summer. Providing acceptable working conditions under these situations is difficult and costly. The ventilation air quantity required in the 3000/3500 orebodies exceeds 550 m3/s when the production rate is greater than 2.5 million tonnes per year. The maximum quantity that can be supplied and exhausted using the existing intake and return ventilation system is estimated at about 630 m3/s. For production rates greater than 3 million tonnes per year, either new intake and return airways will need to be developed or innovative approaches such as controlled partial recirculation used. A description is given of technical and economic investigations conducted at Mount Isa into controlled partial recirculation. During these investigations, a major field trial of a controlled partial recirculation system was undertaken with results indicating that an acceptable working environment can be achieved practically and economically utilising this approach. The cost involved in controlled partial recirculation for supplying the required ventilation quantity when the production of 3000/3500 orebodies exceeds 3 million tonnes per year is examined. A cost comparison between recirculation and other conventional alternatives such as new surface shaft or underground booster fans is included. The results indicate that the option of a new surface shaft will incur a high initial capital cost and moderate annual operating costs. The alternative of underground booster fans will necessitate a moderate capital cost and very high operating costs. Controlled partial recirculation, in this case, offers both the lowest capital and operating costs of the three options evaluated.

Jan 1, 1995

By Plato Malozemoff

While this conference is dedicated to the examination of "Challenges in Mineral Processing," the broader aspect of the pursuit of this subject is Research and Development in the Mining Industry. When I was asked to speak at this symposium, I hesitated to accept. While my early schooling, training and professional occupation were in the field of this symposium, it was so long ago that I no longer feel competent to contribute anything of interest to you except perhaps for a limited historical perspective, which most of you probably already know. However, it might be worthwhile to explore the more general aspect of research and development from the viewpoint of management, as this is the stance from which I dealt with the subject for the last 30 years or so. While most managements generally have a positive view of research and development, few of the leaders in the mineral industry have actually had the personal experience of doing research for a long enough time to have obtained a full understanding and the feel for its place in the long-term technological innovation that our industry must foster. I graduated from the University of California in Berkeley with a Bachelor of Science degree and a major in metallurgy. It was during the great depression of the thirties, and it was difficult to obtain a practical job in the industry. I got a scholarship at the Montana School of Mines and received a Master of Science degree in ore dressing under Professor A. M. Gaudin, followed by another year with him pursuing research. Anyone who studied under him, or knew him well, would assert that this was a unique experience. Gaudin had a brilliant mind and a profound respect for science and the scientific method. He wished to know the scientific basis for every new technological appli-

Jan 1, 1989

By Eileen Ashworth

Introduction A study was completed that investigated the enrollment in mining engineering programs in 24 universities and colleges. All programs considered in the study award four-year bachelor of science degrees in mining engineering. They also provide all the engineers for the mining industry and a large portion of the geotechnical engineers working on environmental problems, storage of hazardous waste, civic, and Federal government underground projects. The numbers used as the base for the study are those reported by each program to SME-AIME and published yearly (SME, 1986). Data for the study came from the period 1975-1985. Also, since some programs include students in related disciplines and special categories, such as cooperative students, a few inaccuracies were unavoidable. A 23-page document has been prepared that reports on the overall picture of current enrollment, the trends, and discusses the results, perceived effects, and what can, or should, be done. There has been an obvious, and dramatic decrease in total undergraduate enrollment since the late 1970s. In 1978, 3117 students were enrolled. In the 1985 fall semester, enrollment was 1022, less than one-third. There were 485 seniors, 265 juniors, 147 sophomores, and 125 freshmen. The downward trend in total enrollment is likely to continue for at least another two years. Class size The catastrophic drop in enrollment is shared by all programs across the country. It does not discriminate between types of programs, coal or hard rock mining, or location. In general, 1985's enrollment is about 30% of whatever the maximum enrollment was in any program, though this varies from the teens to 50%. The latter percentage occurs only for some programs with special circumstances, particularly new programs not well established in the late 1970s. The beginning of the decline in enrollment has occurred at slightly different times as affected by the demise of each program's local industry. The numbers in each class produced from a specific freshmen year (Fig. 1) are worthy of comment. The dramatic drop in enrollment for all classes after 1982 is clearly demonstrated. The timing coincides with the general downturn in the mining industry, when many employed engineers were laid off and new graduates could not find jobs. Also, significantly fewer students are being attracted to mining programs as freshmen. The number of seniors shown seems inappropriate. Where did so many seniors come from and why are so few graduates produced? There is an increasing trend for students to take four-and-a-half or five years to graduate. Therefore, they are counted twice, once when they are first classed as seniors and again the following year. Some students purposely delay graduation to obtain more summer work experience and take additional courses. They believe that this gives them a better

Jan 8, 1986

By J. M. Wempen, M. K. McCarter

"Differential Interferometric Synthetic Aperture Radar (DInSAR) is a satellite-based remote sensing technique capable of measuring centimeter-level surface displacement with high spatial resolution over large areas. Regular monitoring of subsidence due to underground mine development is one potential application of DInSAR, and in this study, the application of DInSAR for subsidence monitoring is evaluated for two mining regions in the mountain west of the United States. In general, DInSAR has potential to identify the shape and extent of subsidence; in some cases, magnitudes and rates of subsidence can be defined. Importantly, the effectiveness of DInSAR for subsidence monitoring depends on the radar band (wavelength), the subsidence rate and the time between image acquisitions, and the topographic and vegetative surface characteristics. INTRODUCTION Differential Interferometric Synthetic Aperture Radar (DInSAR) is a satellite-based remote technique that can be used to measure small surface displacements. Under good conditions, centimeter-level displacements can be measured with subcentimeter accuracy (Buckley, 2000; Massonnet and Feigl, 1998). Additionally, DInSAR data have relatively high spatial and temporal resolutions. Pixels in Synthetic Aperture Radar (SAR) images can have a ground resolution as small as about 3 m, and images often include tens to hundreds of thousands of pixels and cover tens of kilometers. Regions are imaged regularly, and periods between images typically range from weeks to months. In DInSAR, phase measurements from two radar images acquired over the same region at different times are used to precisely measure relative distances (Rosen, 2014). Surface deformation, topography, and changes in the satellite position all contribute to differences in the length of the path that the radar wave travels in each image. SAR sensors use radar with relatively long wavelengths; L-band (24 cm wavelength), C-band (6 cm wavelength), and X-band (3 cm wavelength) radar are used most commonly. Because the wavelengths are long, small changes in the path length of the radar signal can be quantified by measuring the change in the phase of the radar signal between the images. In general, changes in the path length due to changes in the satellite position and topography are known or can be estimated, and centimeter-level changes in the path length due to deformation are measurable. This study evaluates the effectiveness of DInSAR for measuring subsidence in two mining regions in the mountain west of the United States. L-band data from the Advanced Land Observing Satellite (ALOS) and X-band data from the TerraSAR-X mission are evaluated. Imaging characteristics, including the radar band and the time between image acquisitions, are important for effective subsidence monitoring."

Jan 1, 2017

By R. R. Givler

Since the 1860's the good ole days, oil has been nozzle fed to burners under pressure atomizing the oil into droplets -- 1960's has produced vaporized oil that burns oil with the flame color and consistancy of gas -- If you can tell the difference by looking at the flame, gas or oil I?ll buy the lunch. First, we must ask, "Why all the excitement about Blue Flame?" This question is best answered by you after you have studied the principle of operation and see the result. I will attempt to explain both of these so that you can draw your own conclusions.

Jan 1, 1975

By K. R. Griffin

New and developing communication systems enable underground miners to not only connect to the surface from an increased communication coverage area but also to be discovered in the event of an emergency. Communication and tracking systems are required by MSHA regulations, aiming to enhance health and safety and routine production in underground operations. Modeling a mine?s potential communication coverage area will increase overall coverage and efficiency of the communication network itself. Modeling the propagation of wireless communications enables ideal broadcast locations to be found when designing a communications network. Strategic placement of broadcast devices results in a reliable communication network that can better withstand disruption in both daily operation and emergencies. This paper will discuss recent regulatory developments in underground coal communication systems, the implementation of these new technologies, and how communication system?s networks can be modeled and analyzed using computer simulations.

Jan 1, 2010

By B. Seymour

The National Institute for Occupational Safety and Health (NIOSH) is conducting research to develop safe practices for the use of shotcrete as ground support in underground mines, particularly mines operating in weak host rock. As part of this research, tests were conducted with a commercial poly-fiber reinforced shotcrete mix to develop a practical means of measuring shotcrete adhesion strength. Full-scale tests were conducted in a test frame equipped with concrete panels having three distinct surface roughness profiles. Adhesion test fixtures either embedded or epoxied in the shotcrete were overcored into the underlying concrete, and direct tensile tests were conducted to determine the bond strength of the shotcrete cores to the substrate after a selected shotcrete curing interval (1, 3, 7, 14, 28, or 90 days). Measured adhesion strengths typically ranged from 0.5 to 2.0 MPa depending on the curing age of the shotcrete samples. This paper presents the results of these tests, describes the portable test system components, and addresses some of the design issues encountered in the development of a rugged and reliable method for determining shotcrete adhesion strength in underground mines.

Jan 1, 2010

By G. Henry, S. J. Domvile

Arsenic management practices at the Con Mine in Yellowknife, Northwest Territories have evolved over the last fifty years of operations under changing regulatory, economic and technological conditions and incentives. As a result of a processing upset in the mine' s arsenic trioxide reclamation plant circuit in August 1988, arsenic levels in the mine' s tailings pond rose from 30 to over 100 mg V. At these arsenic levels, water treatment operations were unable to meet water licence discharge criteria and the mine itself was under risk of closure due to limited water storage capacity. Under these internal pressures, the mine initiated its own research initiatives designed to restore water treatment operations. The new process developed from the mine's research, utilized the mine's existing water treatment plant hardware but introduced a pretreatment step involving a discrete sludge recycle and removal system. In February 1989, water treatment operations resumed under the new process.

Jan 1, 1992

By Nathaniel Wollman

About nine years ago the President's Materials Policy Co commission under the chairmanship of William Paley released its report entitled "Resources for Freedom." Not long ago the Senate Select Committee on National Water Resources under the chairmanship of Senator Kerr released a study entitled Water Supply and Demand. Both reports contained projections of future water user the report for 1975, and the Select Committee print for 1980 and 2000, It is my task to compare the two reports. In the initial letter from Mr. Kazmann arranging for thus session he suggested that I present "a critical evaluation of the Paley Report's section on water ?ten years later,? which might include a comparison of predicted and actual water-use rates and would spotlight the assumptions which lead to errors in the predictions , . ." It is possible to compare the results of both studies, and it possible to explain art of the differences that can be found between them. The remainder must remain shrouded in doubt, since the Paley Report did not give all details of the methods used in estimating the com¬ponents of water use.

Jan 1, 1961

By R. H. Parker, B. A. Wills, D. G. Binns

Introduction With the increasing need to mine lower grade ores, high energy-related costs in comminution are of major concern. Very fine grinding is needed to liberate the fine mineral particles in these ores. Not only is this expensive, but it leads to greater losses in slimes. Gravity concentration techniques become unacceptably inefficient for particle treatment below 25 to 50 µm, and even flotation fails in the ultra-fine range. Ore from the South Crofty mine near Redruth, Cornwall, was subjected to thermal pretreatment in the hope that differential thermal expansion of the minerals would lead to intergranular cracking, and thus enhanced liberation. South Crofty ore contains about 1% tin as cassiterite associated with a complex assemblage of quartz, chlorite, tourmaline, and hema¬tite in granite and slate. Recovery of cassiterite can be as low as 70%, as overgrinding occurs during stage reduction of the material to 1 mm (primary grinding) and 180 µm (regrinding). Cassiterite is present in grain sizes ranging from submicroscopic to + 10 mm, the bulk being predominantly in the range of 50 µm to 3 mm. Experimental Flat polished sections of the ore were photographed in reflected light using a Vickers M17 microscope. The sections were then heated in a Carbolite LMF4 muffle furnace. The heating rate and temperature were monitored by a thermocouple immersed in the bed of particles. Previous work by Sherring (1981) on the same material showed that a 55% reduction in grinding resistance occurred when the material was rapidly heated and cooled through the quartz inversion tem¬perature (573°C), where a volumetric expansion of 0.86% occurs. The samples were therefore heated to 650°C at 26°/min, and were then water-quenched to room temperature. The effect of heat treatment on the mineralogy and fracture network was assessed by examining the same area after treatment. Results Most of the sections examined showed that extensive transgranular cracking occurred as a result of heat treatment. Such cracking, although weakening the rock and hence reducing the work index, would in no way enhance the liberation of the cassiterite from the host minerals. Intergranular cracking, which would lead to enhanced liberation, was difficult to discern under reflected light, but there was evidence of such cracking in some of the sections examined. Figures 1 and 2 are examples of typical sections before and after heat treatment. Figures la and lb - show cassiterite in hematite, Fig. lb, in normal incident illumination, illustrating clearly that after heat treatment, transgranular fracture is evident in the cassiterite. If any intergranular cracking has occurred, it is not evident in this photograph. Figures 2a and 2b show cassiterite in quartz before and after treatment. Fracturing in both minerals after treatment can clearly be seen, and there is evidence of intergranular fracturing. However, protruding "arms" of cassiterite are severed by transgranular fracture. Subgrains of quartz have also been isolated by trans¬granular fracture. There is major transgranular cracking across the wider sections of cassiterite. Discussion The effect of rapidly heating South Crofty tin ore to 650°C, followed by water-quenching to room temperature, has been studied by observing the fracture networks in mineral grains. The choice of 650°C as the heating temperature was influenced by the work of Sherring (1981), who found considerable reduction in grinding resistance after thermal pretreatment of the same ore. Scheding et al. (1981), however, have shown, by means of a crude calculation, that heat treatment cannot be justified solely on the basis of reduced grinding costs. The cost of heat treatment far out-weighs that of grinding, resulting in the combined costs for heat treatment being over six times that for grinding unheated material. The most economically attractive aspect of heat treatment is the possibility of enhanced liberation of the valuable mineral due to increased intergranular rather than transgranular fracture. Grinding costs would be greatly reduced by improved liberation at coarser sizes, and the costs of ancillary processes, such as dewatering and tailings disposal, would be reduced. The most significant economic effect, however, would be in improved metallurgical efficiency. Improved liberation would increase concentrate grades, and recoveries would be higher, particularly in the case of ores where high slime losses are produced due to the excessively fine grinding required to produce adequate liberation. Manser (1983) has shown that only a 1% increase in tin recovery, at the same concentrate grade, would be sufficient to offset heat treatment costs on South Crofty ore. Heavy liquid analysis and shaking table separation have been used to evaluate the effect of thermal treatment on processing (Binns, 1984; Scheding, 1981; Sherring, 1981). However, treatment of unheated and heated samples of South Crofty ore, ground to the same product size, by such methods have shown little evidence of improved metallurgical efficiency after thermal pretreatment. The large amount of transgranular fracturing revealed by reflected light studies helps to explain this lack of improvement. Nevertheless, from the evidence of some of the fracture work, it is surprising that no improvements in metallurgical

Jan 1, 1988

By John D. Nelson

Unprotected uranium mill tailings impoundments can pose a significant risk to nearby inhabitants and the surrounding environment in the event of a prolonged or catastrophic release of contaminants contained in the tailings. As a result of this potential, reclamation plans for such facilities must include engineering designs to protect against disruption of the tailings and the potential release of radioactive materials. The goals for such engineering designs should be to provide overall site stability for long-term periods with no need for planned ongoing maintenance and to provide a repository for the tailings that will not place a burden on future generations. Although the goal is to provide a maintenance-free system that does not require monitoring, it must be recognized that some period of surveillance would be reasonable. The surveillance period could be relatively short and only needs to assure with reasonable confidence that the reclamation scheme that was implemented is functioning adequately. An investigation was conducted by Nelson, Volpe, Wardwell, Schumm and Staub (1983) entitled Design Considerations for Long-Term Stabilization of Uranium Mill Tailings Impoundments (NUREG/CR-3397). This report assesses the degree of confidence with which long-term reclamation plans can be expected to remain effective over specific periods of time, and to assess the additional effort required to extend the design period from one long-term period to a longer one. This paper presents a summary of that investigation and discusses some of the important conclusions.

Jan 1, 1984

By Y. C. Kim

One-quarter of a century has passed since the "theory of regionalized variables" (geostatistics) was introduced by G. Matheron (1962, 1963) in France. Yet, only during the past decade has geostatistics found broad acceptance in the mining industry. Foremost among the reasons for this time lag was ignorance. The first English treatise on geostatistics was not written until Matheron (1971), and the first published text accessible to mining professionals did not appear until David (1977). Other significant reasons for the slow acceptance of geostatistics included the conservative nature of management in the 1970s minerals industry, and the fact that conventional ore reserve estimation performs reasonably well when confined to massive deposits of base metal and iron deposits having relatively low coefficients of variation in grades. In short, mine engineers and geologists were not willing to accept a new set of tools for problems that they did not see.

Jan 1, 1989

By D. Bhattacharyya

The adsorption and desorption of gold cyanide by activated carbon is significantly influenced by particle size of the activated carbon particles and the chemical environment. A series of adsorption and elution experiments have been performed with ten different particle size fractions. The tests indicate that although the ultimate adsorption capacity is independent of the activated carbon particle size, the adsorption rate is strongly affected by the particle size. Further, desorption characteristics using traditional Mintek and atmospheric Zadra procedures reveal interesting trends with variation in particle size and will be discussed in this paper.

Feb 23, 2014

By M. Manrique, S. A. Pirzada, P. R. Taylor

A thermal plasma-assisted laminar flow reactor was used to evaluate the kinetics of converting alumina to sodium aluminate in flight. Free energy minimization calculations were used to determine experimental conditions. The experimental variables included alumina particle size, alumina/sodium nitrate molar ratio, temperature and residence time. A mathematical model for the conversion was developed and validated. Experimental and mathematical results are presented.

Jan 1, 1998

By Wilbur H. Smith

Geologic mapping techniques at the Bingham Mine have evolved as rapidly expanding applications of geological data have caused new methods to be utilized. The most significant changes in method have been in the preparation of the base map and in computer application of collected data. Formerly maps were prepared by surveying with transit or plane table. Currently a photogrammetric map, on the scale of 1-inch equals 200-feet, is prepared semi-annually and continuously updated to keep pace with the removal of more than 350,000 tons of material daily. Larger scale bases for specific problems, such as areas having unstable slopes, are prepared by use of aerial and terrestial photography and photo mosaics. Note sheets designed for computer application enable fast processing of the data. Application of geology at the Bingham Mine has been increasing rapidly in recent years. The effect of structure, rock type, and alteration on slope stability, the relationship of sulfide mineral distribution to concentrating results, the effect of rock and mineral types on waste dump leaching, and requirements of a reliable internal source of silica flux for smelting are a few of the problems which require the collection and application of geologic data.

Jan 1, 1968

By Bruce H. Mason

The exploration for a commercially acceptable deposit of limestone is consid¬ered by many to be a relatively easy task; however, trying to locate a zone of high calcium limestone of economic thickness within a formation, which outcrops only in a narrow band varying in width from a quarter mile to ten miles, adds considerably to the normal problems experienced during an exploration program. The existence of varying glacial and karst features in the outcrop area intensified the problems encountered and complicated the interpretation of the economic value of the deposit. This paper highlights a recently completed five year exploration program during which approximately 3,900 acres of ground in seven civil townships were evaluated as potential sources of high-calcium limestone. Details are given with respect to the final site chosen and the methods used in determining the suitability of the site. This site exhibited many karat features and several methods were utilized to determine the effect of these features on the gross characteristics of the deposit. Aerial photography for both mapping and interpretation were utilized. Black and white panchromatic photography, black and white infrared and color infrared photography were flown. Resistivity, diamond core drilling and close-interval angering were used to supplement the information obtained from the aerial photography.

Jan 1, 1974

By Chris Laughton, Bernhard Spoerr

"Tunnel inspections are increasingly needed to ensure that aging infrastructure does not fail in service. To this end the time between inspections is being reduced, the thoroughness of each inspection is being increased to provide for a more detailed assessment of conditions and inventory defects. The conventional Tunnel Report, containing hand-drawn maps and/or photos, and a log describing observed defects and areas of deterioration, is being increasingly replaced by LiDAR generated 3-D surface maps. The data collection process that traditionally supports development of a Tunnel Report is labor-intensive, taking crew-days of engineering effort, and requires partial or full stoppage of tunnel operations. In an urban setting, such multi-day interruptions in service are difficult to countenance for a near-capacity tunnel operation. Under time pressures, the detail and accuracy of the manual inspection process will inevitably be compromised, resulting in a high cost, low quality product. As the tunnel inspection window decreases the argument for incorporating laser scanning in to the inspection process is increased dramatically... The 3D scan technology allows detailed and accurate data to be collected within the tight time frames demanded by the owners and operators of critical infrastructure. Not only does the use of laser scanners improve the 3D accuracy of the data collected, it also, enhances the efficiency and safety of the inspection process, reduces data collection and processing costs and enhances the reliability of results over time. The paper will also demonstrate the value of adding photogrammetric data to the 3D Model to show surface defect discoloration. The accurate and detailed data collected by a combination of LiDAR and photogrammetric techniques provide superior data needed to inform critical asset management decisions related to maintenance, repair and replacement."

Jan 1, 2016