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By J. A. Herbst

In spite of potential theoretical and economic advantages of large-diameter ball mills, many manufacturers elect not to build these mills owing to what is perceived as an excessively large design risk. This risk results from the fact that traditional predictions for mill-scale-up to large diameters are not always accurate. It is apparent that alternative methods of analysis and scale-up are required. Recent studies have shown that detailed population balance models which account for important grinding subprocesses, i.e., grinding kinetics, material transport, and classification, are capable of predicting the performance of small- and intermediate diameter mills (up to 4.3 m (14 ft)) from small-scale batch tests. These same models are used in the current study to predict the performance of a "borderline" large ball mill (4.7x5.5 m) at Asarco's Sacaton operation, a ball mill (5.0x5.8 m) at Kennecott's Chino operation, and one of the world's largest ball mills (5.5x6.1 m), at Cities Service Pinto Valley operation. Model parameters required for scale-up have been estimated in a 380-mm diameter batch mill. Predictions are compared with the results of detailed plant sampling in the three plants. For the Sacaton and Chino operations, the error of the predictions was found to be less than 2.5%, while the corresponding error for the Pinto Valley operation was less than 2.7%. It is concluded that proper representation of the major subprocesses of grinding in the model equation is the key to achieving accurate scale-up. Of special importance is the need to account for the size distribution of the grinding media and the influence of the size distribution environment in the mill on grinding kinetics.

Jan 1, 1983

By William Cass, Ellen Caftel Turcotte

The Elliot Lake Centre was established in 1965 as an independent Centre for Continuing Education offering a variety of adult education services. In 1976 all retraining and community college type activities were transferred to the Sault College of Applied Arts and Technology which had opened a branch campus in Elliot Lake. Upon the completion of this transfer, the Elliot Lake Centre was then contracted in 1977 by the Canada Centre for Mineral and Energy Technology to study the feasibility of establishing a research and information institute dealing with various health and safety concerns of the uranium worker. By late 1980, a federal charter was granted for the establishment of the Canadian Institute for Radiation Safety, made possible through the cooperative efforts of the Governments of Canada and Ontario, the Ontario uranium mining and refining companies, and the Elliot Lake Centre. On 1 April 1981 the Institute officially began operations. PROGRAM DEVELOPMENT AND COORDINATION In May 1978 the Elliot Lake Centre initiated a voluntary sputum cytology program for uranium workers. This program was financed by the Ontario uranium mining companies: Agnew Lake Mines Limited near Sudbury; Madawaska Mines Limited in Bancroft, and Denison Mines Limited and Rio Algom Limited in Elliot Lake. In 1981 additional funding was granted by Eldorado Nuclear Limited for a small group of employees at the company's uranium refinery in Port Hope, Ontario. Initially in 1978, program participants were accepted according to length of employment, radiation exposure levels (calculated in working level months) and/or smoking history. These restrictions were abolished within a few months and all uranium workers were encouraged to participate. From 1978 to 1979 the sputum cytology program was medically directed by personnel from the Montreal Cancer Institute. Until 1979 all data maintenance for the program was performed manually, however the effort required to sustain the system increased significantly as the number of participants grew. In September 1979 the Division of Thoracic Surgery at the Toronto General Hospital, under the direction of Dr. F.G. Pearson, submitted a proposal to the Elliot Lake Centre to develop a data processing system to help coordinate the surveillance program. In October 1979, Dr. Pearson became the new Project Director. Director of the Cytology Program is Dr. D.W. Thompson of the University of Toronto who is responsible for all cytologic analyses. Developmental work to establish the new surveillance system was initiated in January 1980 and became fully operational at the beginning of March 1981. The following sections describe the Elliot Lake operations of the sputum cytology program now conducted by the Canadian Institute for Radiation Safety. PROGRAM PARTICIPATION As of 1 September 1981 the sputum cytology program has 518 participants enrolled. Eligibility is restricted only to a willingness to participate and the ability of an individual to produce adequate sputum samples. Each participant registers for the program at the Institute and is given personal instruction on methods of sputum collection. The majority of the participants in this program are employed by the uranium mining industry; some work for firms which are contracted by the larger companies. Many participants are either retired from the work force or receive disability pensions or workmen's compensation benefits. Other participants have been employed in the uranium mining industry and have since gone on to other employment; some work for various federal and provincial governmental agencies concerned with the mining industry. Some participants are referred to the program by their family physicians because of smoking histories and/or various respiratory conditions. A small number of these individuals have never been involved in the mining industry at all. A chart describing program participation by employment is found in Appendix 1. PROGRAM REGISTRATION In the Elliot Lake area, persons interested in registering in the program are required to go directly to the Sputum Cytology office located at the Canadian Institute for Radiation Safety. Each individual is interviewed personally by the Program Officer. For the employees of Agnew Lake Mines, Madawaska Mines and the Port Hope refinery of Eldorado Nuclear Limited, registration is possible during the Program Officer's semi-annual on-sitevisits. Participants are assigned, in chronological order, "program numbers" for easier identification. File labels are color-coded according to place of residence or, in some instances, place of employment. Each file is stamped with the date each sample bottle is distributed. A file contains: all original test results, a completed registration

Jan 1, 1981

The successful exploration for Austin Taylor and Gen. McRae from 1931 to 1940 obscured the fact that I was reaching a period of transition. This was true both in personal and business life. It was probably fortunate that I did not realize how great a change must come after I passed the age of 50. In the personal life of our family the change came when both our children left home to go to school or college. This made home a different place and, because of the absence of the children, Dorothy could devote much of her time and attention to the art she loved so well. She could spend long periods in New York, the center of the nation's art life. Vacations at Tahoe and long pleasure trips made the separation from the children less disturbing but it could never again be the same as it had been in the first 20 years of our marriage. The change In my business life was just as complete, though a little more gradual. While work for Bralorne and General McRae made the "bite" of the Great Depression less painful for us than it was for most consultants and their families, the fact that I was getting older made a new sort of work inevitable. I was 50 years old and the total grew rapidly. Planes and automobiles that made travel easier even in the wilds of Alaska and northern Canada still made it possible for me to look at new prospects, but increasingly often I was exhausted at the end of a day's climb and, if the nature of my work did not change there would soon be no more work. Fortunately work of a new sort came a little at a time. As I became a director of Bralorne and president of its American subsidiaries I had to take on more administrative work, and success of these operations made others want to employ me to help direct policy and value mines. I was also asked to arbitrate contests between mines when technical disagreements were so great that judges or juries could obviously not understand them My consulting for government agencies helped to

Jan 1, 1976

By Russell L. Wood

Introduction It is the morning after and there is one monumental hangover among many, if not most, of the oil companies that invested in mining in the past decade. How an oil company looks at mining depends on the time period. A few years back, around the time of investment, they were probably looking at a balance sheet of their own that was beginning to go wild. Many of their commodity prices already increased two-, three-, or fourfold, with no end in sight. There was a need to invest their earnings someplace before the stockholders or the government got too interested. And that someplace needed to be an industry where their own management skills could be applied. In mining there was an industry amazingly similar to their own. Both worked with nonrenewable natural resources, dealt with the same types of government agencies, and had the same type of critics and pressures from the general population. Oil executives saw mining as an industry that was somewhat backward as compared with their own. They also saw how a generous ration of the capital and management skills, so handsomely bestowed upon the oil industry, could be used to great advantage. But, looking at mining through the eyes of an oil company today, this is what might be seen: • An industry that has been spectacularly unprofitable for the past few years; • An industry of many commodities, any of which can go bad on short notice for protracted periods, for a variety of unpredictable and uncontrollable reasons, or for no reason at all; • A labor-intensive industry, often beset by labor problems. And with only limited potential for further economic mechanization or automation in today's primitive mining environment; • An industry confronted with external, foreign, and political problems, with no reasonable expectation of near-term relief; and • An industry that does not appear to have many "up" periods in its immediate future. And, there is little chance for either big, fast bucks or long periods of large, steady earnings. What Went Wrong? The visions of a few years back seemed as correct then as today's viewpoints seem to be now. What happened to change these views? What went wrong? The simplest and easiest answer is that if the economy was normal back then, nothing would have gone wrong. This is an easy answer but, unfortunately, probably incorrect. Let us take a broad overview. Certain events enabled and prompted oil companies to invest heavily in mining. These same events were major factors in precipitating the worldwide recession that has grievously injured mining and has brought those mining investments into disrepute. Taking a somewhat narrower, but still broad overview, the simi-

Jan 3, 1985

By Lee W. Saperstein

The SME Research Council assists SME and its constituencies in establishing research directions that will benefit the mining industry and its professions. It also provides information about these directions to its membership, to government and to related industrial societies. The 1995 Research Forum, organized and chaired by George Luxbacher, was the second in a series of meetings organized to develop these directions. A copy of the full proceedings is available from SME for $12 plus postage and handling. The first research forum (Saperstein, L., 1993, "Technology for the Future, MINING ENGINEERING, Vol. 45, No 11, November, pp. 1382-85) invited mining industry representatives to discuss the unsolved technical problems that were keeping the industry from greater economic and environmental efficiency. The second forum asked academic researchers to discuss the same general topics from their perspective. It came as no surprise that, in general, the two sets of presenters tackled the same problems. There was no surprise when the academics spoke of the need for fundamental long-term research. What may have been surprising was the number of university people who spoke for near-term research that leads to measurable economic returns or savings. The closure of the US Bureau of Mines (USBM) has changed the objectives and attitudes of the SME Research Council. From being a point of liaison between SME and USBM - a conduit of items from each party to the other the council is now much more on its own. This isolation presents opportunities and hazards. The opportunities are exciting because the council could be the focus for mineral industry research policy if it were properly structured. The hazard is obvious - if there is no bureau, it could be argued, why maintain the council? Many people believe that SME should take the first course and become the beacon for research policy. More than ever, money is being spent on minerals industry research by the federal and state governments - particularly at the mineral-oriented land-grant universities - by industry and by consortia among these groups. SME could be at the hub of these programs. There is a general concern that industry is less able to maintain an economic edge by means of geologic discovery. According to Titley, there will be fewer major, new world-class discoveries except, possibly, at the continental and tectonic-plate margins. Consequently, economic advantage will go to those companies and nations that stay ahead technologically. Given the inevitable diffusion of technology, it can be concluded that technology development, underpinned by research, must be continuous to maintain profits. This is a change from earlier years when change would occur in relatively rare major steps that were interspersed with extended periods of technological equilibrium. Over the fiscal years 1994 to 1997, there has been a 24% cut in research spending by the Department of the Interior (figures from the American Association for the Advancement of Science). This is the largest budgeted percentage cut in research funding of any federal department. Even so, there is still a substantial amount of federal research funding expended in the mineral and extractive-energy industries. The US Geological Survey, Environmental Protection Agency, Departments of Defense and Energy and others expend substantial funds on minerals industry research. Industry - producers and manufacturers - is also spending large sums on research and research-like activities. This activity argues that there is a role for SME's Research Council. Providing focus Consortia. The closure of USBM has resulted in the migration of expertise to consulting firms and to other entreprenrutisl research entities. Many of these groups are creating ad hoc consortia among themselves, nearby universities and industrial partners. The Research Council is well placed to provide an open forum for these con¬sortia. Presentations of research results, as went on in the annual meetings of the Generic Mineral Technology Centers, can help to establish an. archive of results and an avoidance of duplication of research. A continuing sense of research directions can evolve. National Science Foundation. No discussion of consortia would be complete without mention. of the National Science Foundation's (NSF) programs for Industry/University Cooperative Research Centers (IUCRC) and Grant Opportunities for Academic Liaison with Industry (GOALI). NSF is aware of the gap in federal support of science and technology caused by USBM's closure.

Jan 1, 1997

By L. Eros, R. H. King

The US Bureau of Mines has funded several research and development projects in computerized mine monitoring and control. Hardware and software components have been sufficiently developed so that mine operators have been provided with an efficient means to comply with federal regulations and increase mine safety. Several cost benefits have been realized as well, particularly with increased conveyor belt haulage availability. Western Fuels-Utah Inc. approached the Bureau to assist in planning, installing, and evaluating a computerized mine monitoring and control system because of the agency's research experience in this area. The installation was planned for Western Fuel's Deserado mine, located in Rangely, CO. Since a large, complex, underground mine producing about 2.4 Mt/a (2.7 million stpy) of coal was projected, the company anticipated significant benefits in safety and efficiency through a computerized monitoring and control system. A major part of the cooperative program was to document and evaluate the system design, installation, and operation. This will assist others to adequately design, specify, install, and operate future systems. Mine description The Deserado mine plan and layout have important impacts on the monitoring system requirements. Long range plans are to produce 2.4 Mt (2.7 million st) of clean coal annually from two longwall sections and four continuous sections. Presently, two continuous miner sections operate under 213 m (700 ft) of overburden in the 2.3 to 2.5 m (7.5 to 8.5 ft) thick D seam to develop main, submain, and panel entries have developed for a longwall. These began operation in December 1986. Belt conveyors haul the coal from the mining sections to a 1.4-m (54-in.) belt located in the upper compartment of the slope. The lower compartment contains a hoist for men and material transport. From the slope, the coal moves to two 9 kt (10,000 st) raw coal storage silos, then to a 680-t/h (750-stph) preparation plant. After cleaning, a 5.5-km (3.5-mile) overland conveyor carries the coal to a clean coal slot storage and rail load-out facility. An electric locomotive then transports the coal to the Bonanza Power Plant in Utah. Allen-Bradley monitoring and control hardware and software controls the preparation plant, with two PLC-3 programmable controllers and a Process Control Industries D-1200 color graphics interface. The system operator uses three "smart" color video display units and an alarm printer for hard copy records. Originally, it also monitored and controlled the conveyors from the bottom of the slope to the top of the raw coal silos, the preparation plant, the overland conveyors, the main mine ventilation fan, and the hoist. Some of these features, though, were later transferred to the mine system.

Jan 2, 1988

By Zoheir Khademian, Gabriel S. Esterhuizen, Morgan Sears

Based on the 2010-2019 Mine Safety and Health Administration (MSHA) accident report database, 91% of reported ground control accident in the US longwall mines were caused by gateroad roof instability. This can be related to the significant changes in loading conditions that gateroads are subject to from the development to the longwall abutment loading phases, combined with the thinly bedded shale roof, found in many US longwall coal mines. One of the challenges in designing efficient support systems is to understand the roof instability mechanisms along with support-roof interactions under this complex loading condition. Field monitoring of roof displacement and stress changes coupled with detailed analyses using numerical models are well-documented techniques to study the causes of roof instabilities. However, traditional modeling techniques require additional calibration to simulate delamination and buckling of shale roof, one of the main roof instability mechanisms in longwall mines. One alternative modeling technique is the UDEC Bonded Block Method (BBM) where bedded roof and support interactions can be explicitly captured. This paper presents the development of a BBM model of a longwall entry at a 180 m depth of cover with a three-entry gateroad layout along with roof extensometer monitoring results. The models are validated against the monitoring data, showing the potential for BBM numerical models capturing the complex roof and support system interactions to assist with optimizing gateroad layouts and support systems.

By III Sadler

Processing bauxite and clay ores to reduce Iron content to levels low enough for the ores to be suitable raw materials for such products as refractories and abrasives has long been regarded as a diffi9ult problem. Standard magnetic separation processing of the untreated ore has been attempted by previous investigators with only limited success due to the finely divided state and weak magnetic susceptibility of the iron minerals (hematite, geothite, etc.) present in these ores. The new process described in this paper consists of calcining the finely crushed ore at 500 to 800 C and then reducing (with hydrogen, carbon monoxide, etc.) the iron oxides present to magnetite or elemental Iron. The magnetic susceptibility of iron in these forms is enhanced 40-to 100-fold over that of hematitie and is readily removed by simple magnetic separation. Starting with a 2.7% Fe20s Alabama bauxite ore, a 1.5% Fe20s product was produced in one pass through a Davis tube magnetic separator with 95 + % recovery of the iron-free bauxite fraction and a 20% Fe20a magnetic product. These findings suggest that with the addition of light calcination, reduction and magnetic separation steps to the conventional refractory grain production process, the large U.S. reserves of high-iron bauxites could be used.

Jan 1, 1990

By Vincent R. Bovino

Introduction Only a person fresh from an information vacuum could not know the status of this nation's economy. The inability of the US to compete in the world marketplace is manifested in many industries, from shoes to computer chips, from cars to copper. What industry will next fall prey to world competition? Perhaps the question should be, what insustry will next fall prey to declining productivity? American industry is being forced into an era where the focus must be on productivity, quality, cost control, and competition in the world marketplace. It is approaching a change that could rival the American Industrial Revolution. The future of the US is bright only if it can increase productivity by trying different and new ways to manage its businesses and people. Unlike the easy successes during the 60s and 70s, success in the decades ahead will depend on an ability to compete in the world market. Any operation can achieve unlimited productivity by developing the resources within its employees. As an industry, mining has harvested the earth's resources. As an industry in trouble, it now has to learn to tap human resources to release the energy and creativity in each person. Recently, I worked with a mining operation to reopen a mine and implement a different management approach. The extensive changes resulted in a 50% reduction in cash cost of producing silver (from $0.40 to $0.19/g or from $12.50 to $6 per oz). Thus, an unprofitable mine became an attractive business venture without technological changes or significant capital infusion. The operation is union-free, in spite of being in a highly unionized area. The mine implemented a real productivity improvement process called "gain-sharing." Employees now recognize their individual success is tied to the success of the business. They recognize the day of the free lunch is over for mining employees. This paper will explore three areas related to productivity: • some of the unspoken "whys" of the mining industry's paralysis and how management has caused unproductiveness in mining operations; • major components of a productivity improvement process; and • characteristics common to companies with successful productivity plans. Unspoken whys When things go wrong, everyone tends to point a finger at someone, anyone. This industry has blamed every conceivable person, corporate group, government agency, foreign government, and private group for its failures. The fault finger will not work anymore. Nobody is listening. It is a characteristic of winners in management to assume responsibility for less than acceptable performance. Excellent people tend to blame others less for problems. Everyone involved in mining should shoulder part of the blame for the industry's illness. Is the problem low prices or our high operating costs? To regain our status in the world marketplace and increase our productivity, we need to painfully and honestly talk about our mistakes.

Jan 3, 1986

By W. R. Reed, J. P. Rider

"The Pittsburgh Mining Research Division of the U.S. National Institute for Occupational Safety and Health (NIOSH) recently developed a series of models using computational fluid dynamics (CFD) to study airflows and respirable dust distribution associated with a mediumsized surface blasthole drill shroud with a dry dust collector system. Previously run experiments conducted in NIOSH’s full-scale drill shroud laboratory were used to validate the models. The setup values in the CFD models were calculated from experimental data obtained from the drill shroud laboratory and measurements of test material particle size. Subsequent simulation results were compared with the experimental data for several test scenarios, including 0.14 m3/s (300 cfm) and 0.24 m3/s (500 cfm) bailing airflow with 2:1, 3:1 and 4:1 dust collector-tobailing airflow ratios. For the 2:1 and 3:1 ratios, the calculated dust concentrations from the CFD models were within the 95 percent confidence intervals of the experimental data. This paper describes the methodology used to develop the CFD models, to calculate the model input and to validate the models based on the experimental data. Problem regions were identified and revealed by the study. The simulation results could be used for future development of dust control methods for a surface mine blasthole drill shroud. IntroductionIn surface mines, production drilling is an essential process in blasting to fracture the hard rock overburden for removal. During the process, considerable amounts of respirable dust are produced. Past sampling at the shroud area of blasthole drills had documented time-weighted-average respirable dust concentrations ranging from 8.68 to 95.15 mg/m3 (Organiscak and Page, 1995) and 1.04 to 52.30 mg/m3 (Listak and Reed, 2007). These high dust concentrations, which may contain silica, can lead to respirable dust overexposures for the miners working nearby. These overexposures can lead to silicosis, an occupational lung disease that has no cure and is ultimately fatal.Two basic methods are used to control drilling dust: a wet suppression system or a dry collection system (Cecala et al., 2012). Dry drilling techniques using a dust collection system are preferred in rural mining locations where a constant water supply is not available, and in the case of rotary drilling where water is associated with accelerated bit wear due to bearing degradation and hydrogen embrittlement. In addition, dry drilling eliminates freezing-related issues with water in colder climates. Dry dust collectors are highly effective at removing dust, especially the finer material, as long as they are properly operated and maintained (Listak and Reed, 2007; Organiscak and Page, 2005)."

Nov 1, 2016

By Pedro Sanchez-Mejorada

Laguna del Rey is the name of a dry lake bed located in the State of Coahuila, Mexico in a semi-desertic terrain typical of the basin and range physiography. Química del Rey, S.A., a subsidiary of Industrias Peñoles, has been producing sodium sulphate since 20 years ago, from brines pumped from the sub-surface of the present playa. The spent brine is used as raw material for the production of magnesium oxide. An extensive, lenticular deposit is found just below the playa. It consists mostly of glauberite (sodium-calcium sulphate) and blöedite (sodium-magnesium sulphate). The glauberite occurs as thin crystals oriented at random and leave many void spaces among them. These intercrystalline spaces are partly filled with mud, but the whole mass of the evaporite is still very porous. A brine that contains in solution ions of sodium, magnesium, sulphate and chlorine occupies the voids of the sponge-like evaporite body.

Jan 1, 1984

By Q. Xiao, R. Naidu, W. Li, S. Song

Acid mine drainage (AMD) derives from the oxidation of sulfide minerals, primarily pyrite (FeS2), and is the most severe environmental issue facing the minerals industry. The most common short-term approach to AMD treatment is migration control, such as acid neutralization and metal/metalloid and sulfate removal, through the addition of alkaline materials, including lime (Ca (OH)2), limestone (Ca CO3), gangue minerals and industrial wastes. This requires the continuous input of materials and may result in the production of a vast amount of secondary sludge requiring further treatment and disposal. Addition of chemicals is usually more important in metal/metalloid removal than in sulfate removal unless the sulfate is present in very high concentrations. A more promising long-term strategy for AMD prevention is source control through the complete removal of pyritic minerals and encapsulation of potential risk minerals by coating with impermeable surface layers. This is regarded as the most cost-effective approach, although the mechanisms underpinning this and the implementation procedures are yet to be fully elucidated. It is likely that long- and short-term practices can be combined to optimize the remediation of contaminated mining sites. Some factors such as differing geological and mineralogical characteristics and transportation costs must also be considered for the successful implementation of AMD prevention and remediation strategies. This review also considers some implications for AMD remediation, but the promising bioremediation of AMD is not discussed as it has been extensively reviewed.

By Andrew J. Regis

The methods of evaluation of industrial minerals occurring on Federal lands have different meanings if the evaluations are done by a company rather than a government agency. For example, when the Bureau of Land Management (BLM) conducts an examination of mining claims, this is commonly referred to as a "validity examination," whereas it is an "economic evaluation" when performed by a company. Not only is there a difference in nomenclature in these evaluations, but there is a general lack of expertise in the Federal government on industrial minerals in general. A metallic mentality still prevails in the U.S. Forest Service (USFS) and the BLM. Because of this, many validity exams on industrial-mineral deposits commonly just skim the surface concerning economics and marketability. The BLM and USFS place a high amount of emphasis on past administrative case law pertaining to the validity of industrial minerals under the 1872 Mining Law and, rightly so, on marketability, which also is heavily addressed in case law. When the BLM considers marketability, only the marketability of a particular industrial mineral for only the primary use for which it was located is considered and any value-added markets cannot be included. The BLM defines marketability based only on the value of the mineral material in its in situ or raw state, rather than value-added through processing. Another difference in the evaluation of industrial minerals by government and industry is the question of by-products. When a company evaluates a mineral material it looks at all the markets. The BLM looks only at that market for that locatable mineral for which the claim was located. In other words, sales from non-locatable by-products cannot be used to support marketability or the prudent-man rule (i.e., oversize silica sand from a glass-sand claim being sold for construction sand, road base, fill, etc.). The question of reserves also can present conflicts. An industrial-mineral company will often try to identify all the reserves available for a possible future development. They must do this for financial backing and support from upper management. The BLM, however, will limit their validity examination only to those reserves that meet the prudent-man rule and marketability tests. The BLM will validate reserves sufficient to last 25-30 years, based on available market. The development of industrial minerals on Federal lands is a difficult process, and, if the 1872 Mining Law is changed, it could become not only more challenging but also more costly. The industry must become more tolerant of the mineral specialists in the BLM and the USFS. On the other hand, the government mineral examiners must become more aware of the importance of industrial minerals in everyday living, and the economic evaluation of these materials.

Jan 1, 1999

By Tassos Grammatikopoulos, Mike Johnson, Niels Verbaan

Seabed polymetallic nodules, which contain significant quantities of metals key to electrification (nickel, cobalt, copper, and manganese) can be processed using several different metallurgical processing options, including direct smelting and subsequent hydrometallurgical refining of the copper/nickel matte, ammoniacal leaching (gas reduction or Cuprion), and acid leaching (often reductive). Many of these approaches suffer from reduced cobalt extraction, difficult physical performance, or overall circuit complexity in general, leading to increased risk to the overall project. SGS has considered pressure acid leaching of nodules for further investigation, as publicly shared data on this processing route stems from the 1970s and 1980s and is not always easily accessible. This paper will detail the series of tests conducted and provide updated results obtained (high Ni/Co/Cu recovery with limited Mn/Fe), as well as comment on the potential treatment options on the product solution and residue.

Feb 1, 2025

By Tassos Grammatikopoulos, Mike Johnson, Niels Verbaan

Seabed polymetallic nodules, which contain significant quantities of metals key to electrification such as nickel (Ni), cobalt (Co), copper (Cu) and manganese (Mn) can be processed using several different metallurgical processing options, including direct smelting and subsequent hydrometallurgical refining of the copper/nickel matte; ammoniacal leaching (gas reduction or Cuprion); and acid leaching (often reductive). Many of these approaches suffer from reduced cobalt extraction, difficult physical performance, or overall circuit complexity in general, leading to increased risk to the overall project. SGS has considered the pressure acid leaching of nodules for further investigation, as publicly shared data on this processing route stem from the 1970s and 1980s, and are not always easily accessible. This article details the series of tests conducted and provides updated results obtained — high Ni/Co/Cu recovery with limited manganese/iron (Mn/Fe) — as well as comments on the potential treatment options on the product solution and residue.

Sep 1, 2025

By D. T. Iseley, David Bennett, Christopher Norris

The microtunneling test program is one of three main elements of the research project, "Trenchless Construction: Evaluation of Methods and Materials to Install and Rehabilitate Underground Utilities." The other elements of this project include an evaluation and demonstration of horizontal directional drilling technology and pipeline rehabilitation systems. The research is a Corps and Industry cost-shared project funded under the Construction Productivity Advancement Research (CPAR) program. The laboratory partner is the U.S. Army Engineer Waterways Experiment Station (WES), Geotechnical Laboratory. The industry partner is the Louisiana Tech University's Trenchless Technology Center. Industry participants are contributing over half the total cost of this research. The overall objective of the CPAR program is to improve productivity in the U.S. construction industry, thereby enhancing the competitiveness of the U.S. industry in domestic and overseas markets. The Corps and other federal and state agencies will benefit by realizing reduced costs, enhanced safety and better products and services as the products of this research program are developed, tested, and pushed into the market place. The microtunneling demonstrations and evaluations were performed during September and October 1992 at a specially constructed test facility built at WES in Vicksburg, MS. The test facility is 104 m (340-ft) long, 5 m (16-ft) wide, and 4 m (13-ft) deep. It was constructed, ironically, by first excavating a trench into which 6 different types of soils were placed and compacted in approximately 18.3 m (60-ft) long sections. The soil profiles include a lean silty clay (loess), a dry sand, highly plastic buckshot clay, wet sand, clay gravel and silt. The interfaces between soil profiles were sloped to simulate mixed face conditions as the machines exit one zone and enter another, and provided challenges to ground control and alignment and grade control during these transitions. Moisture and density tests were performed on all materials in each lift to assure uniformity. Horizontal inclinometers and 3 levels of settlement plates were installed at key locations in the test bed. The settlement plates and rods and the horizontal inclinometers, together with surface survey points, provided data to evaluate settlement and heave along the test section. Penetration resistance was measured in each section of the completed test bed. Strain gages were installed in 8 of the 0.6 m (24 in.) diam. Hobas pipe sections to measure strains in the pipe as it was being jacked into place. Steering jack loads, jacking thrust loads, and cutterhead torque were also measured during the drives. The results of these tests will be used together with other information to develop guidelines for conducting feasibility studies and selecting proper methods compatible with anticipated conditions.

Jan 1, 1993

By Thomas L. Hurst, Joseph M. Hans

INTRODUCTION The former Shiprock uranium mill site is located in the community of Shiprock, New Mexico on a bench overlooking the San Juan River (Figure 1). Both Shiprock and the mill site are located on the Navajo Indian Reservation. The millsite was built on a 230 acre tract leased by Kerr-McGee Oil Industries Inc., and was operated from 1954 to 1963. The Vanadium Corporation of America and its successor, the Foote Mineral Company, operated the mill from 1963 to 1968. During its entire operation, 1.5 million tons of uranium ore was milled producing 3711 tons of U308 concentrate. The concentrate was sold to the former U.S. Atomic Energy Commission. During milling, the ore was crushed to less than 35 mesh and acid leached to remove the uranium. The [ ] uranium was removed from the leach solution by solvent extraction and the uranium-barren solution discharged into raffinate ponds for disposal by evaporation and seepage. The spent solids (tailings) were pulped with waste process fluids and water and discharged to form tailings piles. The piles (ponds or dams) were formed with earth starter dikes. The dike walls were then raised using the separated sand fraction of the tailings. The slime fraction of the tailings were discharged into the diked impoundment. Since only a small fraction (0.25 percent) of the ore was U308 by weight, most of the ore bulk ended up as wastes. The wastes contain nearly all of the uranium decay chain radionuclides present in the ore except uranium. The mill was shut down and partially dismantled before the lease expired in 1973, and the remainder of the mill and wastes reverted back to the Navajo Tribe which was the lessor. Portions of the millsite were then occupied by the Navajo Engineering and Construction Authority (NECA), a Tribal enterprise. In order to provide skilled personnel to operate earth moving equipment, a heavy equipment operator's training school was also established on the mill site and was administered and operated by NECA. The U.S. Public Health Service (PHS) and the Environmental Protection Agency (EPA) staff conducted radiation surveys at four inactive uranium millsites on the Navajo Reservation in April 1974. During the survey of the Shiprock millsite, it was noted that the training activities were degrading its radiological condition. Both the PHS and EPA staff recommended that the training activities be directed towards the decontamination of the millsite area and interim stabilization of the tailings piles. Preparation for the decontami-nation work commenced in April 1974. In order to facilitate the decontamination activities, the mill site and its contaminated environs were divided into major areas labeled A through F (Figure 2). Areas A, B, and C are defined as "perimeter" areas and contained surface contamination ranging from 5 to 30 cm deep. Area D defined the mill yard and contained contamination ranging from 0.6 to 5.5 m deep. Area E contained several raffinate ponds which were removed to line up the northwest boundary of the tailings pile and to move the contaminants away from the vicinity of the occupied on-site buildings. The contaminants in Area E ranged from 0.05 to 5.5 m in depth. Area F encompassed the ore storage yard. Contaminants in this area ranged from 0.18 to 1.2 m deep. Washes, however, had contamination exceeding 7.6 m deep.

Jan 1, 1981

By Phillip R. Moyle

Voluminous deposits of commercial-grade phosphate occur in sedimentary strata in a 350,000 km2 (135,000 mi2) area of the middle Rocky Mountains of North America known as the Western Phosphate Field. The Permian marine strata that host the phosphate were deposited on the western margin of the North American craton and subsequently deformed, first by folding and thrust faulting of the Laramide orogeny, and then by Cenozoic Basin and Range block faulting. Carbonate fluorapatite is the primary phosphorus-bearing mineral. Organic matter is abundant in some strata, and both biogenic and non-biogenic pyrite are also present. Certain strata are enriched in several trace elements, especially in arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), molybdenum (Mo), selenium (Se), vanadium (V), uranium (U), and zinc (Zn). Phosphate has been mined from the Western Phosphate Field for nearly 100 years. Phosphate mining and processing constitutes the largest mineral industry of Idaho, producing more than $600 million in processed mineral value in 1997. Resource management agencies, phosphate producers, and others are concerned about the release of Se from phosphate mine wastes, especially at Maybe Canyon, and the potential effects that Se and other trace elements may have on the environment and on human health. U.S. Geological Survey (USGS) Mineral Resources Team scientists initiated a multidisciplinary study of the Permian Phosphoria Formation and related rocks in the south- eastern Idaho sector of the Western Phosphate Field in response to a request by the U.S. Bureau of Land Management (BLM). Studies to date reveal that Se is present in several phases, including native Se, and in an as yet unidentified form, possibly an organo-Se compound. Selenium is also present in pyrite and sphalerite. Selenium concentrations range from 1.2 to greater than 1,000 parts per million (ppm) in samples collected from exposures of the Meade Peak Phosphatic Shale Member of the Phosphoria Formation (Meade Peake) at Enoch Valley. The results suggest that Se concentrations vary spatially across strata and with depth, perhaps comparable to spatial variations of phosphate and organic carbon concentrations throughout the Western Phosphate Field demonstrated in previous studies. Some Se-enriched strata may be of adequate dimension to allow selective extraction during mining. Such units could be handled separately from the main ore process or waste streams and isolated in order to reduce the potential for release of Se to the environment

Jan 1, 2001

By W. E. Cobb

The financial implications of environmental liabilities are becoming staggering, particularly for mining companies. The Environmental Protection Agency's (EPA) Record of Decision (ROD) list for Superfund mining sites has some pretty hefty financial commitments, such as the $10 million operable unit remedy for the Yak Tunnel at California Gulch (in Colorado) or the $40 to 60 million remediation at Bunker Hill (in Idaho). These costs are driven by the large volume and areal extent associated with historical waste management practices at mining sites. (It's difficult to have a low-cost remedy for a 20-square-mile site.) Unfortunately, there are other ways of generating environmental liabilities besides Superfund, such as non-compliance with Clean Air Act provisions, stormwater permits, or National Pollutant Discharge Elimination System (NPDES) permits. In the last 2 years, EPA has increased enforcement in its regulatory programs, which has resulted in increased fines and criminal actions. Leaders in other industries (primarily the chemical and manufacturing industries) are viewing environmental liabilities as a strong motivator to select engineering approaches carefully based on technical, legal, economic, and philosophical perspectives. Industry interest in waste minimization programs comes from the concept that it is economically advantageous not to create waste in the first place. Waste minimization programs typically balance increased front-end capital investment with the minimization of potential long-term environmental liabilities as a way to achieve the lowest total-or life-cycle-cost. A side benefit of waste minimization programs is that they tend to improve overall regulatory compliance. Waste management practices are also becoming philosophical, as evidenced by a May 11, 1992, Business Week article: Companies that incorporate innovative thinking on sustainable development will do more than clean up or prevent their own pollution. They'll make and distribute a product more efficiently than ever, worry about its lifelong environmental impact, plan for recycling, and get their suppliers on the bandwagon. This type of approach will require a new mind-set, new tools, and adjustments throughout the organization. A key aspect of waste minimization or life-cycle waste management programs is the incorporation of environmental costs into economic analyses that compare various waste management alternatives. However, the incorporation of environmental costs into an economic analysis can be more difficult than initially thought. As noted above, new tools-or even a new toolbag-are needed, such as new accounting methods that track and assign the true lifetime environmental costs of a particular product. One piece of the new toolbag is life-cycle cost analysis, which is discussed in this paper. To simplify the discussion, this paper looks at the total costs associated with a given mining site. The concepts presented in this paper, however, can be applied to any mine waste management decision. The ultimate extension of life-cycle costing, as presented in the Business Week article, is to include the potential environmental costs throughout the life of a metal. At this point, I am perplexed on why, let alone how, to include the potential downstream environmental costs (i.e., the costs associated with smelting, manufacturing, use, and recycle or disposal) throughout the life cycle of mined copper, lead, or zinc.

Jan 1, 1992

By J. W. Stevenson

At this 5th U.S. Mine Ventilation Symposium I would like to focus your attention on safety and the contribution of the ventilation engineer over the past 50 years. This conference affords us the opportunity to express, to listen, and to learn. As ventilation engineers it is indeed an exciting time--a time that not only stimulates our imagination but also pin points our aims in our quest to obtain zero fatalities by the year 2000, the goal expressed by William J. Tattersall, Assistant Secretary of Labor, Mine Safety and Health Administration. In the past, coal mine ventilation has often been unfortunately synonymous with explosions and resulting fires. Those not familiar with us do not recognize the painful evolution of the coal mining industry and particularly the evolution of mine ventilation. To put my presentation into perspective, I recently reviewed a U.S. Bureau of Mines Bulletin No. 586 - "Historical Summary of Coal-Mine Explosions in the United States 1810 - 1958 prepared by H. B. Humphrey Mining Health and Safety Engineer. This bulletin was published in 1960. Mr. Humphrey stated "In 1946, factors contributing to the explosions occurring from 1941 to 1945 were: (1) The rapid increase in the use of electrical equipment at face regions where gas and dust are most likely to be found; (2) the increased demand for coal with the desire to obtain maximum tonnage per machine at minimum cost, which in many mines has resulted in neglect of even rudimentary precautionary measures; (3) multiple-shift operation without provision of time for adequate maintenance of equipment, effective rock dusting, and testing for gas; (4) decrease in supervision owing to demands on supervisors for maximum tonnage and loss of competent supervisors to other employment; (5) lack of effective supervision, owing to numerous new conditions, some of them war-connected; (6) inability to obtain adequate equipment repair and replacement parts; (7) shortage of labor and inadequate training of coal-mine workers; and (8) failure of both miners and mining officials to show regard for safety in changing from hand-loading to mechanized methods". Most of the eight factors listed by Mr. Humphrey continue to affect our work lives as mining engineers. The increased demand for coal with the desire to obtain maximum tonnage per machine at minimum cost has never changed. The local and regionalized coal industry of the 40's is today competing against the world coal market. Our mines work or shut down based on cost. This has always been the case. During the five year time-frame Mr. Humphrey was documenting, 345 miners were killed in major explosions. A major explosion was one in which five or more miners were killed in a single accident. In addition, 105 more miners were killed in minor explosions for a total of 450. What a wanton waste of life. What fears, anxieties, miseries, and sufferings were created by these accidents. However, we must remember and keep in mind that the coal mining company officials, engineers, and foremen, the governmental agencies- federal, state, and local - were using the technical tools and knowledge available to operate the mines as safely as they could. Obviously mine ventilation engineering technology was woefully inadequate.

Jan 1, 1991