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By A. C. Mollison

In November of 1983 a fire inside the autoclave caused the curtailment of operation of the Kidd Creek pressure leaching facility. Subsequent repairs and recommissioning of the autoclave in 1984 allowed Kidd Creek to increase its production of zinc as originally planned. This paper describes the operation of this process from 1984 to 1988 and details major mechanical work carried out on the vessel in 1.988:

Jan 1, 1990

By J. J. Lukasko

The U.S. Bureau of Mines developed an alternative electrochemical process for the production of calcium metal. The current industrial practice is costly, complex, and inefficient. The Bureau method involved electrowinning of a calcium-tin alloy followed by electrorefining to produce calcium metal. In the electrowinning cell, CaCI2 was fed to a KCI2-CaCI2 electrolyte. The calcium was electrowon at 6500 C into the pure molten tin cathode until the cathode contained 7.5 wt pct Ca. Current efficiency for electrowinning averaged over 90 pct. The resulting calcium-tin alloy served as the anode for the electrorefming cell, which employed a [CaC~-CaF2] fused salt as the electrolyte. Calcium metal was electrorefmed at 8500 C with a current efficiency of 85 pct based on calcium metal recovered. The calcium metal analyzed 99.2 pct, which is purer than commercially produced calcium.

Jan 1, 1990

By Jr. Schnakenberg

The automation (robotization) of coal mining activities at the face offers improvements in worker safety and productivity. The evolutionary introduction of autonomous, intelligent robotic machines to perform the most hazardous tasks may become a reality within the next 10 years. The U.S. Bureau of Mines Robotics and Automation research program is aggressively pursuing the development of the enabling technology necessary to achieve this goal. This program consists of both core and applications research, each focused on the fundamental issues of robotic technology. In the short term, the research is directed specifically to the robotization of present-day underground equipment and is being performed in a manner that can make incremental improvements in safety and productivity. The long-term goal is the development of intelligent autonomous mining systems.

Jan 1, 1990

By Eugene D. Krupa

Mine 33 of Beth Energy has serious and complex roof cutter problems causing delay of the advance rate of both the entry development and longwall face retreat. The cost of maintaining these entries is very high due to the requirement of wry heavy artificial supports. It was suspected that this problem was caused by multiple factors including high in-situ horizontal stresses and weak roof in the problem areas. In order to alleviate the problem, proper design of panel entry and roof reinforcement were considered. This paper presents the results of extensive measurements in experimental panel entries of Mine 33 in order to assess the performance of the designed structure and roof support system during the entry development and longwall retreat. An experimental panel entry has been designed and implemented. The designed parameters were varied seeking for the most ideal parameters which provide stable roadways. Changing these parameters accompanied instrumentation of roof, floor, and pillars. Typical instrumentation, including stress meters, convergence measurement stations, and borehole borescope were utilued. Gnensive monitoring of the behavior of the designed structure and support system led to the development of a complete stress-deformation history of the roadway and an ideal roof reinforcement, support system, which reduced the cost of entry development by less than a third of the previous method.

Jan 1, 1990

By S. J. Page, W. E. Wallace, P. Bolsaitis, D. Eppelsheimer, M. J. Keane, J. Poston, J. Harrison

"Respirable-sized dust particles from a clay mine and mill were examined for aluminium and silicon content by scanning electron microscopy-energy dispersive X-ray analysis at incident electron energies of 5--20 keV. Most of the high silica content particles, those which had a silicon to silicon plus aluminium signal fraction, measured at 20 ke V, of0.9 or greater, showed a decrease in the silicon fraction of signal with decreasing incident electron energy, down to values of between 0.6 and 0,8 at 5 keV: this decrease was a function of particle size and composition. Simple models for silicon fractiol) of signal vs incident electron voltage suggest this behavour is due to a heterogeneous particle structure in which an aluminosilicate coating occludes the surface of a silica particle core. The coating survives incubation in a major component of pulmonary surfactant.INTRODUCTIONMINING and some other dusty workplace atmospheres are monitored for respirable dust and quartz dust for purposes of occupational health protection, respirable quartz dust being a known cause of pulmonary disease. Respirable quartz exposure data are acquired also for epidemiological research on the correlation of pulmonary disease prevalence with respirable dust composition and concentration. For these purposes quartz content often is measured on collected dust samples by X-ray diffraction or in spectroscopy. Scanning electron microscopy-energy dispersive X-ray analysis spectrometry (SEM-EDX) is also used. The first two methods measure the bulk composition of a multi-particle dust sample; SEM-EDX measures the elemental composition of single ·particles. These methods as typically applied, including SEM-EDX with a 20-30 kilo-electron volt (keV) electron beam accelerating potential, do not distinguish homogeneous distribution of impurities in a particle from possible heterogeneous surface distribution. These measurements of quartz content are not always accurate predictors of the prevalence of dust-induced disease (ROBOCK and BAUER, 1990), which implies that the biologically available quartz surface may not be equivalent to conventionally measured quartz content of respirable dust in some exposure settings. Using a minor modification of conventional scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDX) protocols on samples of settled and airborne dust from a clay mine and mill we have detected heterogeneity with depth for aluminium impurity in high silica content particles, indicating that some of the quartz or 'free silica' respirable particles of the dust are aluminosilicate occluded. Coatings were not removed by incubation of the dust in a surrogate pulmonary hypophase surfactant fluid."

Jan 1, 1990

By Donald A. Voigt

This publication is intended as a guide for persons responsible for obtaining classifications and approvals Tor explosive compounds, mixtures, or devices from the U.S. Department of Transportation (DOT). It deals with the procedures for obtaining a recommendation for classification of an explosive compound, mixture, or device through the Bureau of Mines. Completion of the procedures detailed in this guide is necessary to obtain a final classification of an explosive compound, mixture, or device and assignment of an "EX" number by DOT, which will allow the producer to offer the explosive for shipment within the United States. This guide also gives procedures for obtaining United Nations (U.N.) classification for shipping outside the United States.

Jan 1, 1990

By Gérald Riverin, Bernard Salmon, Marlo Gagnon, Réemi Asselin, Alain Cazavant, Michel LaBrie

"The Ansil deposit is located in the Noranda mining camp in the southern part of the Abitibi greenstone belt. /twas discovered in 1981 and production began in 1989 with proven reserves of 1.58 Mt grading 7.2% copper, 0.9% zinc, 26.5 glt of silver and 1.6 glt of gold. It is centered at a depth of 1.3 kilometre and represents one of the deepest ore discoveries ever made from surface.The deposit consists of a single massive sulphide lens located at the contact between the Northwest Rhyolite and the Rusty Ridge Andesite. The lens strikes north-south and dips 50° east. The thickness of the lens may reach up to 35 m and can change very abruptly both along strike and along dip. The maximum thicknesses of the sulphide lens are reached in its upper (western) and at its lower (eastern) edges, thus giving the deposit its present shape of two sulphide domes connected by a thinner central portion. The lower dome is underlain by a thick accumulation of massive magnetite which may reach 10 to 15m in thickness. The upper and lower domes are underlain by two distinct pipe-shaped zones of stringer and disseminated sulphides which merge with a larger stringer zone at depth.The Ansi/ deposit displays strong relationships between its morphology and the distribution of metals. Hydrothermal alteration consists of chloritization and sericitization. Chlorite alteration is closely associated with stringer sulphide mineralization while sericite is developed in diffuse zones bordering the chloritic zones. Unlike other similar deposits, the Ansil deposit is characterized by very extensive alteration and sulphide mineralization in the hangingwall of the massive sulphides. Several features of the deposit are consistent with an origin from a submarine hydrothermal system which was particularly long-lived, and which thus promoted the build-up of very high fluid temperatures with extensive replacement (and enrichment) of pre-existing sulphides after their original deposition onto the seafloor."

Jan 1, 1990

By K. M. Parida

The kinetics of dissolution of manganese dioxide in dilute sulphuric acid solution have been investigated using iron pyrites as a reductant. The dissolution rate of manganese is independent of the speed stirring but depends upon temperature, particle size, specific surface area of manganese ore, acid concentration, Fe(II) concentration and amount of pyrite. The activation energy is 43.6 KJ/mol and the linear relationship between the rate of dissolution and lido indicates that the reaction is chemically-controlled. The redox reactions of MnO2 with iron pyrites and Fe(II) are the rate-controlling reactions.

Jan 1, 1990

By Jr. Raleigh

Three run-of-mine bituminous coals, which ranged in rank from low volatile to high volatile A, were floated at nominal -28 mesh (590 µ m), -100 mesh (150 µ m), and -400 mesh (37 µ m) feed particle sizes with selected pyrite depressants and a dispersant. For the coals tested, pyrite and ash-forming minerals were usually rejected best at a -100 mesh feed particle size. Depressant additions tended to improve flotation selectivity between pyrite and coal. When joint dispersant-depressant systems were used at -100 mesh (150 µ m) feed particle sizes, the total sulfur content of the clean coal decreased further. For a comparable coal yield, less fuel oil collector was required for the flotation of -100 mesh coal than was required for the flotation of either -28 or -400 mesh feed.

Jan 1, 1990

By R. C. Bryce

"Selbaie is located northwest of Joutel, in what is known as the fourth east-west volcanic sediment group in northwestern Quebec. The main metals produced are copper and zinc, with important contents of both silver and gold. Production comes from an open pit mine on the A-I zone and from two underground mines on the B zone and the A-2 zone. Each mine gave rise to important capital investment programs for construction and mine development, all of which were managed and staffed with company-hired, non-union personnel. Production from all sources now exceeds 7000 tonnes per day, with a workforce of540 regular employees. Of particular interest technically is the high recovery of B zone reserves underneath 40 m of overburden cover, the low-cost capital development of the A-2 zone, the computerized control of open pit mining, and the successful copper-zinc separation of the A-1 zone ore. Due to the low grades of the mineral deposits, efficiency in all aspects of the production process, is essential to the success of the operation.LocationThe Selbaie Mine is located 82 km northwest of the locality of Joutel in northwestern Quebec (Fig. 1). Access to the mine is by an all-weather road, 32 km of which is paved. A second road access to the site is via La Sarre, 134km to the southwest. Employee access, materials transport and haulage of copper and zinc concentrates take place over both of these roads."

Jan 1, 1990

By I Hustwick

New Zealand Steel Mining Limited operates two independent sand mining operations on the West Coast of the North Island of New Zealand. Waikato North Head 30 km south of Auckland supplies ironsand concentrate as the raw feed for New Zealand Steel's works at Glenbrook and Taharoa 70 km further south, exports ironsand concentrate to Japan.   Taharoa uses two sets of six low pressure Warman centrifugal pumps in series to load bulk ore carriers 3 km off shore through two underwater pipelines. Waikato North Head delivers the ironsand to Glenbrook 18 km through a 200 mm ID buried pipeline using two stages of high pressure positive displacement (HPPD) pumping.   A high level of operating and maintenance expertise has been developed since commissioning the two systems which are proving to be reliable, efficient and of minimal impact environmentally.

Jan 1, 1990

By Richard A. Andre, R. Larry Grayson, Thomas Simonyi

"INTRODCICTIONThe search for the cause(s) of coal workers' Pneunoconiosis continues despite the vast amount of research that has been undertaken over the past forty to fifty years. Good correlation between the mass of dust inhaled over workers' lifetimes and the incidence of the disease has led to the development of effective environmental standards and implementation of good procedures for the control of dust generation and dispersion in the working place. Research has only begun, however, to uncover the biochemical mechanisms involved in initiating the disease.Correlation between the rank of the coal seam in which miners worked and disease incidence and severity is acknowledged worldwide, but the agents in the higher rank coal seams which cause CWP arc still not defined. The basic components of the coal seams, i.e., the elements and minerals, are generally known, but the way in which they interact with human pulmonary cells is largely still a mystery.The process of disease development is a biochemical one which depends on the characteristics of the pulmonary cells within their immediate biochemical environment and the characteristics of invading respirable coal mine dust particles, probably both chemical and physical ones. The cell-particle relationship, therefore, must be defined, and both cells and particles must be characterized according to properties which potentially are involved in the disease process.Following such characterization, specific respirable dusts from different coal seams, which appear to have different effects on coal workers, must be obtained or constructed and then used in experiments designed to determine dust toxicity or the response of animals exposed to the dusts.The results presented here focus on characterizing properties of respirable coal mine dust particles collected from operating longwalls in West Virginia and Virginia Longwall panels were selected for analysis because the respirable dust in the coal face areas is largely uncontaminated by rock dust and analysis of the dust yields results unconfounded by rock dust."

Jan 1, 1990

By F. Villanueva Araya

Compania Minera Disputada de las Condes (CMD), an Exxon Affiliate stewarded by Exxon Coal and Minerals Company, operates two' copper mines and concentrators in Chile. Pilot plant studies were initiated in 1984 using a 0.46 meter and a 0.91 meter diameter column for the cleaning of copper concentrate. This eventually resulted in the design and operation of a rectangular column with an area of 6.8 m2, increasing the final copper concentrate grade from about 30% to almost 32'1. Cu without any loss in copper recovery. Evaluation studies of a commercial bubble generator as against the previously used filter cloth air sparger are now in progress.

Jan 1, 1990

By M. K. Alam

Chemical Vapor Deposition (CVD) processes are currently attracting special attention in materials processing. CVD processes are now used to produce special materials in the form of thin films, coatings, composites, and optical fibers. This process produces material of high purity, in complex shapes, and in a variety of microstructures. It is a capital intensive process, involving use of high cost raw materials. Modeling simulations have the potential of reducing the time for CVD . process design, and the need for experimentation. Modeling would, therefore, appear to be an attractive option for producing a product of acceptable quality. At Ohio University, progress has been made in modeling of CVD processes, specially in the areas of optical fiber preform fabrication, and fiber coating.

Jan 1, 1990

By James J. Scott

Research and development has been carried out on the patented Dynamic Rock Anchor, tradenamed DYNA-ROK and DYNA-ROK PLUS Anchors, which are manufactured and marketed by Ingersoll-Rand Company. This paper will present the results of field testing of this revolutionary new concept in ground control. Geologic conditions will be described where the plastic sleeve of the DYWA-ROK anchor alone is sufficient to provide anchorage and also, where in softer ground conditions, the DYWA-ROK PLUS is applied. The rationale for making the decision as to the type of fixture to be employed, the length of plastic tube to be used and the quantity of resin are explained. Pull test data will be shown from eight different coal seams in the Eastern United States where the product has been installed.

Jan 1, 1990

By R W. Givens

Comparison tests were performed on 6 emulsion concentrates, 3 microballoon sensitized emulsion concentrates, and 2 water gel concentrates from 8 different sources with ANFO used as a control standard. Variables measured include density, detonation, velocity, detonation pressure, calculated borehole pressure, viscosity, and lead cylinder deformation for blends of 15%, 30%, and 45% concentrate and AN/ANFO blends. Comparative results are presented for detonation velocity vs. deformation, and percentage of inherent air vs. deformation for these blends. It was hoped that these tests would serve as a tool to facilitate the comparison of different manufacturer's concentrates in AN/ANFO blends for equivalent performance characteristics and to help evaluate these products on an equal basis for bid solicitation purposes.

Jan 1, 1990

By C. A. Carroll

In February of 1989 the Mission Complex of ASARCO Incorporated completed an expansion of its concentrator, raising the base mining rate from 25,900 TPO (28,500 STPD) to 37,200 TPO (41,000 STPD). The expansion was accomplished by extending the twelve existing Mission ball mills in length, by installing the grinding circuit from Asarco's idled Sacaton Concentrator along with various auxiliary equipment, and by modifications to the flotation circuit and water systems. This paper will give a brief history of the consolidation of the ore body which made the expansion possible and explain the various parts of the expansion.

Jan 1, 1990

By Rudolf E. Greuer, Linneas W. Laage, Xinton Chang

All output is saved in the file MFIRE OUT m the di¬rectory and on the disk containing the program The file can be inspected with a text processor and sent to a print¬er, if needed CONTENTS OF OUTPUT FILE The comment lines, reference temperature, air densi¬ty, a table of the units of measure for the results, and the average values are shown at the beginning of MFIRE OUT All input data will be shown in the output file if LOUT on Control line number 1 is _<-1 For each contamination source, a new branch will automatically be setup The new airway and junction ID numbers will not interfere with the original numbering scheme of the data file Next are the results of the selected simulation(s) in the following order network balancing, network balancing considering temperatures, transient-state modeling, and altered equilibrium due to fire and distribution of the contaminants. Depending upon the contents of the data file, and the simulation selected, attention, warning, and error message will be shown at locations where calculations resulted in unusual conditions

Jan 1, 1990

By J. J. Fallon

The subject is "Mergers, Acquisitions and Divestitures in Industrial Minerals, but my remarks could also be applied to new product development, resource development and other new business development activities. At the kernel of the subject is due diligence in major decision-making, that is, where major money amounts and a large corporate commitment are at stake. The "due diligence" means how carefully we do our homework before making the decision. The homework or feasibility study addresses different parts of the decision. In the industrial minerals business the study seeks to uncover the pros and cons in: o The mineral reserves, quantity, quality, mineability, access, etc. o The environmental impact of mining, processing and transporting. o The economics of operations. o Financial aspects o Legal aspects o Many other aspects o And -oh yes! the marketing aspects.

Jan 1, 1990

By D. Leppert

Mr. Garrett brings up several interesting points with respect to the proposed API specification for "nontreated bentonite." However, although not explicitly stated, these specifications are being written based strictly on bentonites from the Wyoming/South Dakota area. Other sodium bentonites may be suitable for use as drill mud but will be unacceptable since the specifications are designed for Wyoming bentonites. Regardless of the API&apos;s intent that its specifications are intended only as guidelines, they are generally adhered to on an international basis and, for practical purposes, might as well be chiseled in stone. Estes (1986) notes that the quality of bentonite available from Wyoming producers has steadily declined since the early 1960&apos;s. The plastic viscosity: yield point (PV:YP) ratio was included in the current API 13A specification primarily to prevent excessive polymer treatment of lower quality bentonite to make drill mud. However, with development of polymers designed to control YP, this specification cannot ensure that only high-quality bentonites are used for drill mud. Nor will the new specifications for untreated bentonites. Other sodium bentonites are available. Bentonite produced in southeast Oregon demonstrates superior performance characteristics without addition of polymer or other chemicals. However, the exceptionally high purity of these deposits leads to a relatively high YP:PV ratio since the naturally high YP probably results from the higher purity and smaller particle size of this bentonite (Rath. 1986 and personal communication). These bentonite; typically have a smectite component exceeding 90% (Rath, 1985), compared with 70% to 75% smectite for typical Wyoming bentonites, as determined by X- ray diffraction and tests for colloid content. As evident from the accompanying table, the untreated Oregon bentonite has excellent rheological properties, though different from Wyoming bentonites due to the high purity. Additionally, this bentonite reacts well with polymers typically used in the oil industry, making it eminently suitable for use in a low-solids mud system. The extremely low grit content, less that 0.5% on a 75 mm (200-mesh) wet sieve, greatly exceeds the standards set for Wyoming bentonite. Optimum rheological properties are obtained at a higher moisture content than Wyoming bentonites. At 10% moisture, API 13A maximum, the clay is overdried, again reflecting the high smectite content. In summary, the specifications proposed by the API Task Group will ensure that only Wyoming producers can supply "nontreated bentonite to the oilfield since specifications are

Jan 1, 1990