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By P. K. Berger, G. T. Lineberry, H. P. Cole, J. V. Haley

Sixty-five simulation exercises were developed for teaching and testing problem solving and decision making skills to miners and mining engineers. The exercises focused on judgment and decision making for preventing and controlling mine emergencies. The structure and field testing of the exercises are described, and sample frames of individual exercises are presented. Empirical data are summarized about the effectiveness of these simulations based on the performance scores of a national sample of miners and mining engineers.

Jan 1, 1994

By M. S. Klima, M. Fofana

The use of a laboratory-scale magnetic fluid-based separator for coal separations was examined. A Frantz laboratory magnetic separator was modified by fabricating new pole pieces of the appropriate geometry to provide the proper magnetic field gradients. Two separation chambers, which were constructed of Plexiglas, were designed to fit between the pole pieces. A commercially available, water-based, ferromagnetic fluid was used as the separating medium. The separating density was changed by varying the current intensity of the electromagnet coil. Both batch and continuous separations were made using 0.59 x 0.50-mm and 0.18 x 0. 15-mm coal. The results are compared to those obtained using organic liquids.

Jan 1, 1998

By T. Y. Yan

An effective elution technique has been developed for recovering uranium from ion exchange resins loaded in the carbonate leaching process. The procedure employs direct elution with acid. In comparison with conventional base elution, the procedure yields eluate of higher uranium concentration, results in a more complete elution, keeps the performance of the ion exchange resin at the fresh stage, reduces acid consumption, eliminates carbonate consumption and reduces waste for disposal. The technique has been successfully demonstrated in the field and patented. It lends itself to commercialization.

Jan 1, 1988

By M. S. Klima, A. P. Pinkerton

Solid-bowl (decanter) centrifuges are used extensively to dewater slurries in a wide range of industries. However, the application of decanters as classification devices is not as common. In this study, the performance of a continuous, pilot-scale, solid-bowl centrifuge was evaluated when classifying an ultrafine coal slurry containing nearly 60% material less than 10 µm. The test conditions included centrifuge howl and scroll speeds, volumetric feed rate, solids concentration and pond depth. Centrifuge performance was evaluated using size selectivity curves and the corresponding performance parameters, along with product yields and solids concentrations.

Jan 1, 2002

By R. L. Wolfrom, R. Hogg, S. Chander

A gravimetric method for measuring rates of capillary rise in powders was explored. Methods to improve reproducibility and consistency of the results were investigated. In particular, the effects of particle size and packing uniformity were addressed. Studies of the wetting behavior of both spherical glass beads and irregularly shaped synthetic graphite particles by various organic liquids were carried out. Standardized procedures for bed preparation will be described. The applicability of the Washburn equation for surface energy evaluation in such systems will be discussed. Key words: Wettability, Powders, Capillary rise, Surface chemistry

Jan 1, 2003

By M. E. Rossi

Reconciliation of production information is critical to evaluating the effectiveness of the predictive models, and to allow for optimization of mining operations. Whether mining open pit or underground, mine-to-mill reconciliations can be one of management's better tools to perform proper accounting, and a very useful evaluation and optimization tool. This paper proposes a set of criteria and objectives for a typical reconciliation program; also presents a stepwise, logic approach to performing reconciliations, and discusses the benefits and costs associated with the up-keeping of the information. It also highlights some of the potential pitfalls involved, and methods used to avoid collecting misleading information. These issues are illustrated with an example of a model-to-mine-to-mill reconciliation program being implemented at an operating mine; the program involves multiple predictive models (Long-term and Short-term block models), different open pit and underground mines, stockpiling, and at least 23 different mill streams. This paper presents the initial results of the program implemented at Minera Michilla S.A.

Jan 1, 1999

By Danforth R. Hale

The pressure of military use of quartz resonators led to efforts to Grow high, grade quartz crystals in Germany and in Great Britain during 19)3-25, and was responsible for a series of U.S.A. Signal Corps contracts beginning in 1946 with the Clevite Corporation (as the former Brush Development Company), Bell Telephone Laboratories, Antich College, and others. The technique of growing crystals from the melt, such as KI, NaBr, was already commercially inuse Quartz could not be so grown, since its utility depends on the form stable below 573°C, and, even if it could be grown from an extraordinarily viscous melt, the higher form passing through this transition becomes twinned. Again, several crystals were being grown commercially from water solutions; quartz, however, is listed in the common literature as being insoluble in water. Fused quartz, or vitreous silica, was chosen as raw mater¬ial by the European experimenters because of its thermodynamically lesser stability than quartz, and various alkaline solutions were tried for the purpose of enhancing the solubility.

Jan 1, 1964

By Todd Kilduff, Michael Tinney

The North Temple Tunnel pedestrian underpass in Salt Lake City, UT was built using a pipe canopy method that met significant challenges in potentially running ground conditions. Kilduff Underground Engineering (KUE) was the designer for the 20-foot-diameter SEM tunnel, Design-Build contract. Geotechnical data indicated ground conditions consisted of loose silty gravel for the majority of the face overlying soft to medium stiff clays in the tunnel invert. KUE designed a pipe canopy as pre-support to stabilize cohesionless gravels in the crown, a shotcrete initial liner with lattice girders to minimize disturbance of the finer-grained materials in the invert and a final liner with waterproofing system. The project was presented with a few unique challenges, primarily from the adverse ground conditions, but was successfully completed safely and schedule

Dec 1, 2022

By L. A. Weakly

The requirement for large diesel equipment to be certified for operation in potential gassy mine conditions in western oil shale mines motivated a design engineering project to develop a dry exhaust conditioner system to replace traditional wet scrubber technology. A dry exhaust conditioner for a 600 hp diesel engine was designed and fabricated for retrofitting into a 600 hp underground haul truck. The engine conditioner package was taken through a simulated certification process at the Mine Safety and Health Administration (MSHA) Approval and Certification Center to refine test procedures and to uncover any flaws in the dry exhaust conditioner technology. The engine/exhaust system was then installed in an underground haul truck to demonstrate mine-worthiness of the system. No inherent features were discovered that would prevent the system from meeting test requirements. However, the tests did point out several deficiencies in the prototype design.

Jan 1, 1989

By D. Tao

The presence of insoluble slimes in potash ore poses a serious processing problem to the potash industry. These insolubles must be removed prior to potash flotation because of their high adsorptive capacity for amines which are generally used as collectors in the subsequent sylvite flotation. This is usually accomplished by scrubbing of the ore in brine followed by hydrocyclone classification to separate slimes from the salt particles. Insoluble slimes that remain in the ore after the desliming procedure are depressed by reagents such as guar gum or starch during sylvite flotation. In this research, the feasibility of using GP clay binders to replace guar gum for potash flotation was investigated. Batch mechanical flotation tests were conducted with the potash samples provided by a leading potash company. It has been found that GP clay binders increased potash concentrate yield and recovery at the same product grade. Effects on potash flotation efficiency of flotation process parameters such as impeller rotation speed, slurry temperature, binder type, dosage and conditioning time have been investigated to establish the optimum conditions for flotation. Binder GP374G33 has been identified as the optimum substitute for guar gum as slime depressant in potash flotation.

Jan 1, 2008

By HJ Marais, J A. van Niekerk

An investigation was initiated by BILLITON Process Research and Gold Fields Limited for the efficient removal of thiocyanate and cyanide from leach solutions. This led to the development of the ASTERTM process, an acronym for Activated Sludge Tailings Effluent Remediation. The biological degradation of thiocyanate and cyanide in effluents provides an alternative treatment to the more traditional processes. This occurs with a large number of micro-organisms which include bacteria, actinomycetes and fungi. Cyanide and thiocyanate are degraded to ammonia and carbon dioxide. Most forms of cyanide-metal complexes are generally removed through a co.mbination of oxidation and sorption into the biofilm/biomass. Since the ASTER™ process has commercial applications, a patent has been lodged for the ASTER™ process. A culture containing thiocyanate degrading organisms has been deposited with the Australian Government Analytical Laboratories (AGAL). The identification of the bacteria is in progress. Tailings arising from a cyanidation process tend to contain cyanide and thiocyanate. The presence of these species prevents the recycling of this water upstream to a bioleach circuit due to its toxicity to the bacterial culture. Increasingly stringent legislation for the land disposal of cyanide containing solutions also necessitates the treatment of the solutions before disposal.

Jan 1, 2000

By Kenneth L. Myers

The net balance of the inflow and outflow of water in a tailings storage facility has major economic implications in any large mining and milling operation. In a net precipitation environment it can control the ultimate size and storage capacity of a facility or dictate the need for an expensive treatment and discharge program. In a net evaporation environment it can control the extent of the water rights acquisitions required for makeup water and dictate the number and size of expensive wells and pumping and delivery systems. The elements considered in a water balance analysis include the anticipated production rate, the water content of the slurry used to deliver the tailings, inflow from precipitation and snowmelt, and losses from evaporation and seepage. The mine can exert significant control over only one of these elements: the production rate. All others are subject to considerable uncertainty from month to month and year to year. The traditional approach is to analyze in a spreadsheet environment by making simplifying assumptions and using monthly mean or "average" values for precipitation inflows and evaporation losses. Often the analysis will be repeated with values subjectively assigned to represent a "wet" year or "dry'' year. The probabilistic approach uses the same basic spreadsheet model in conjunction with a probabilistic simulation add-in program allowing probability distributions to be substituted for any of the deterministic variables. The resulting analysis shows the full range of variation possible for each parameter of interest (i.e., available return water, makeup water required, storage, seepage losses) and estimates the exceedance probabilities for each. The potential uses and advantages of the probabilistic approach are discussed.

Jan 1, 1992

By M. L. Young, M. S. Klima

Hindered-settling columns are used throughout the minerals industry for both size and density separations. In this study, the performance of a continuous laboratory-scale hindered-settling column was evaluated for various particle systems. The test variables included solids composition, water rate and column height. Column performance was evaluated using partition curves and corresponding performance parameters.

Jan 1, 2000

By D. R. Zeni

Today's mine development requires the safe, expedient and economical construction of vertical shafts for both ventilation and access. This construction must be accomplished within diverse ground conditions. Advancements in large-diameter shaft drilling have led to many exceptional mechanical refinements in shaft-drilling technology. The author traces the history of the equipment and methods employed by the large-diameter shaft-drilling industry and explores the likely paths of future development. Case histories that illustrate the adaptability of shaft drilling as a versatile tool for advanced, worldwide mining operations are cited. Safety, scheduling, costs, environmental impacts and capabilities are discussed.

Jan 1, 1996

By Debbie Nakamura, Daniel Tempelis, John E. Shamma

The Metropolitan Water District of Southern California established a Board of Consultants to assist them in administering the design and construction of the Inland Feeder Program tunnels. The Board acts as an expert review body for the owner, looking at key issues that can potentially impact the success of the program. The use of the Board evolved over the life of the project, and its composition was modified to better address the needs of the owner, and the Program requirements. The experience, function, and value of such a board is analyzed and discussed in this paper.

Jan 1, 2003

By L. G. Austin

The use of crushed power station slags, both natural and coated, as granules for roof shingles shows some promise. Test shingles weathered for some years showed rust spotting and granule deterioration as serious problems. Chemical analysis on a particle-by-particle basis using a scanning electron microscope-energy dispersive spectroscopy system showed the wide variability of chemical composition of the granules within a given sample. Analysis of particles acting as sources of spotting within the weathered samples showed high iron contents but no rules could he developed for predicting the long-term stability of different compositions.

Jan 1, 1990

By J. D. Cooper, D. W. Thompson, J. Basiuk, W. Cass, R. Ilves

The Department of Thoracic Surgery and Pathology at the Toronto General Hospital have had a long standing interest in the early detection and treatment of carcinoma of the lung. Our initial experience was with a population at risk due to a prolonged period of cigarette smoking. More recently our efforts have turned to industrial exposure, specifically in the nickel and uranium industries. [Initial Screening Project] (1) For a three year period 1963 to 1966 a cytology screening program was carried out through the Out-Patient Department. The study was limited to cigarette smokers over 40 in age. A total of 1586 patients were examined. Of the sputa collected, the classification is seen in Table 1. There were 11 malignant sputa present. Added to this number were 25 patients with symptoms, normal chest X-rays, but malignant cells on cytology, and a further 5 patients in whom an abnormality (eventually proven non-malignant) showed on X-ray, and sputum showed malignancy which was radio logically occult. (Table II). This gave a total of 41 patients with malignant sputum who were evaluated between 1960 and 1966. The clinical course of these patients is seen in Table III. Only 19 of 41 patients had localization and treatment of their tumour during that study period and this low rate of localization attests to the technical difficulties endoscopy in that day presented. The method of localization was as follows: a) 6 patients showed an area of segmental pneumonitis somewhere in this time period b) Using the rigid bronchoscope localized the tumour in 9. This was proven by direct biopsy, and frequently required more than one bronchoscopy over a prolonged time period. c) bronchograms and tomograms showed abnormalities in 5 patients. Of these 19 patients, 5 were treated by radiotherapy because of general condition or refusal of surgery. Three of the irradiated patients died of recurrent cancer within three years. The other two died within one year of unrelated disease. Fourteen patients underwent resection, with one operative mortality. At pathology, the tumours were "in situ" in 6 and invasive in 13. There was no evidence of nodal spread. When last followed up in 1979, there were no cases of recurrent tumour and no cases of second lung primary tumours. Similar experiences have been reported from the Mayo Clinic (2), Johns Hopkins (3) and Memorial Hospitals (4). Early detection of radiologically occult tumours which are in situ or minimally invasive has given uniformly good results. There have been no deaths from recurrent or metastatic cancer in surgically resected patients, and only one second primary tumour has been detected. Interestingly, the Hopkins group reports that 5 patients with Stage I squamous cell tumours refused operation. One refused any treatment and died of disease at 12 months. Three were radiated, and were alive from 14-38 months post-treatment, all with evidence of recurrent disease. [Sudbury Sintering Plant Study](5) From 1948 to 1963 an open travelling-grate sintering process was employed to convert nickel sulfide to nickel oxide at an International Nickel Company operation. The environment in this plant was particularly dusty and filled with fumes. It became apparent by 1969 that the incidence of bronchogenic carcinoma was markedly increased in workers from this plant. A concerted effort was made to track down all workmen with this exposure. During 1973 and 1974, 268 men were studied. Chest radiographs were done and showed no mass lesions. Sputum was collected on three consecutive days and analyzed. There were 12 men with malignant sputum, all of the squamous cell variety. Two refused any investigation, one presenting 31/2 years later with extensive hronchogenic carcinoma, and the other 5 years later with extensive carcinoma of the maxillary sinus. In the remaining ten patients careful rhinolaryngeal examination as well as a detailed bronchoscopy, involving examination, brushings and biopsy of all pulmonary segments was carried out. One patient was found to have laryngeal carcinoma and was treated by radiation. In nine patients, the malignancy was localized to the lung, leading to six lobectomies, two pneumonectomies and one sleeve lobectomy at operation. However, the follow-up in these cases suggests a different biological behaviour with these industrially related tumours. While no tumour has recurred locally, one patient has died of metastatic cancer and two patients have developed second and one patient a third pulmonary primary cancer. However, survival has still been much better than wits radiographically manifest lung cancer. [Technique of Localization] (6) Following a careful rhinolaryngeal examina examined and then the lower respiratory tract is examined. This is all performed under general anaesthesia. The trachea is examined with the rigid Jackson bronchoscope, collect-

Jan 1, 1981

By J. Eldridge, A. J. Carter, D. N. Leavell

Minpro International has developed an innovative, flexible¬shaft impact crusher that produces glass aggregate from mixed¬color, post-consumer glass. The crusher operates with low power and generates a subangular aggregate, with minimal fines. Output is screened to yield sized aggregate, which can be used directly as surfacing material in Owens Corning's shingle process. Metal, plastic and paper waste is preferentially removed by the Minpro system. Duval County and the City of Jacksonville collect more than 12,000 tons of glass bottle waste per year. It is anticipated that a successful end-use application by Owens Corning, will allow increased collection and cost-effective glass recycling in north Florida.

Jan 1, 2002

By P. T. Luckie

More efficient classification with a single hydrocyclone through equipment and/or operating design changes does not appear possible. However, improvement in classification efficiency by increasing the sharpness index and decreasing the apparent by-passing while changing the cut size is possible through proper staging of inefficient hydrocyclones. But feasible multistaging requires achieving the necessary material balances around the units. Because of the interactions among the units, these balances require extensive iterations. The final step before commerical installation should be a laboratory demonstration, in order to define the control algorithm required to maintain stability. However, eventually a sufficient knowledge base should be developed that will permit simulation in place of laboratory testing as well as the incorporation of a feed forward strategy.

Jan 1, 1989

By Harold E. Goetzman, Blair R. Benner, Shaolin Zhong, Rodney L. Bleifuss

A commercial high pressure roller press (KHD 90125) was installed at the Coleraine Minerals Research Laboratory for testing in October, 1994. Pilot plant evaluation of the high pressure roller press has shown that it can be used as an alternative to the rod mill for the comminution of taconite. A series of pilot plant tests were run to compare roller press products to rod mill products in a simulated taconite flowsheet using magnet separation and closed circuit ball milling. Further investigation of a hybrid grinding system, roller press crushing followed by ball mill grinding, indicate that the combination may represent the most energy efficient system for taconite processing.

Jan 1, 1998