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By G. R. Green

The centre of the mining operations of the International Nickel Company, Ontario Division is Sudbury, a city of 160,000 population located 240 miles northwest of Toronto (Fig. 1). Within thirty miles of this city and located around the rim of the geological formation known as the Sudbury Basin are the ten underground mines and one open pit operated by the Company (Fig. 2). There are also four developing mines, three in the Sudbury area and one at Shebandowan, near the city of Thunder Bay, Ontario and approximately 150 miles north east of Duluth, Minnesota. In 1971 the mines produced 22,800,000 tons, 20,600,000 tons from underground and the balance from open pits. Also located in the Sudbury District are facilities to extract and refine the metals contained in the ore. There is a nickel refinery located at Port Colborne on Lake Erie. An additional nickel refinery is under construction near Sudbury. Fifteen elements are recovered from the Sudbury ores, nickel, copper, iron, sulphur, gold, silver, cobalt, tellurium and the six platinum group metals, platinum, palladium, iridium, rhodium, ruthenium and osmium. In 1966 a major expansion program was undertaken to meet increasing market requirements. Coinciding as it did with a severe

Jan 1, 1972

By Henry H. Rubin

Rubber and its contributions to the economic solutions of environmental problems in the minerals industry. The intelligent applications of "Rubber" to systems of noise abatement, vibration isolation, dust containment, weak and corrosion resistance has proven economically beneficial. Intelligent application requires a thorough understanding of the nature of the material, knowledge of the process wherein it is going to be applied, and consideration of the environmental conditions in which it will serve, for these determine the proper amount, type, compound and configuration for an economically successful application.

Jan 1, 1979

By L. G. Sobral, J. E. Hoffman, T. J. Keefe, A. J. Monhemius, O&apos

The kinetics of electrodeposition of gold from dilute solutions of alkaline KAu(CN)2 at different gold and free cyanide concentrations on a gold rotating disk electrode were investigated by use of a steady-state linear potential scan technique. The design and performance of a laboratory electrowinning cell with a reticulated nickel cathode, operating in the flow-through mode, for the removal of low levels of gold ions from aqueous cyanide media is described. During the batch recirculation of oxygen-free gold cyanide solutions, the gold concentration was reduced from 10 ppm to <0.5 ppm with current efficiencies of up to 80%. The influence of solution flow rate through the cathode and of the pore size of the reticulated nickel foam is discussed. The removal of gold ions from solutions of low ionic strength was also investigated.

Jan 1, 1993

By Roberto Zaragoza

Historically, the control of flotation operations has been viewed by many as an art. Only recently has process measurement and control come to be viewed not as an ?art? but as a very complex and productive science. In recent years, process control applications to flotation plants have been established and already some gains have been reported for several industrial operations using individual stabilizing control loops including level, pulp flow, pulp density, reagent addition rate and pH (Paakinen, 1979; Hales, 1985). The use of process control computers combined with on-line x-ray florescence (XRF) in industrial flotation circuits has made the application of more sophisticated control techniques feasible in the mineral recovery process. In spite of the availability of reliable instrumentation in modern flotation plants, satisfactory control strategies are difficult to develop and implement. Extremely important factors such as changes in ore type, liberation characteristics, flotability, degree of oxidation on particle surfaces, and specific gravity constitute unmeasured disturbances to the process. Most current control systems cannot adapt specifically to such disturbances.

Jan 1, 1987

By Catherine T. Aimone

A computerized cost model has been developed to simulate the technical and economic effects of strip mine blasting in the vicinity of structures. Current surface mining regulations restrict the allowable level of production blasting as a function of this distance. Blast design modifications,&apos; therefore must be employed when blasting in the vicinity of homes to ensure compliance with federal and state regulations specifying limits to the seismic effects generated from a blast. The blasting level allowed. is computed by the charge weight of explosives per delay from the following scaled distance formula: [ ] where W is the charge weight per delay, in kilograms (pounds), D is the distance factor corresponding to the regulatory limit of peak particle velocity to which a structure may be subjected to. Current regulations specify 2.54 cm (1.0 in.) per second corresponding to a SD factor of 27 (60) (Federal Register, 1977).

Jan 1, 1982

By H Sohn, R. R. Fernández

Microscopic gold inclusions in sulfide minerals cannot typically be extracted by conventional cyanidation. The gold ore must be pretreated to oxidize sulfide minerals associated with gold and to remove other minerals and chemical compounds that interfere in the cyanidation leaching process. The recovery of gold from refractory sulfidic-carbonaceous ores after roasting pretreatment was studied. With the addition of an oxygen-containing gas (e.g., air or oxygen-enriched air), sulfides of iron, zinc. copper and other metals are tramformed into solid oxides or sulfates and gaseous sulfur dioxide at elevated temperatures (e.g., 400° to 800°C). When the sulfides are oxidized, individual particles lose internal volume and become porous, allowing leaching solutions access to the gold. The structural characteristics of the calcine have a strong influence on the eventual recovery of gold by cyanidation. These characteristics are strongly dependent on the roasting conditions and roasting method. The optimum combination of particle size, roasting temperature, reaction time and oxygen concentration in the off-gas was determined for a typical refractory sulfidic-carbonaceous ore from the Carlin Trend in Nevada. The tests were run using a 150-mm laboratory rotating tube furnace and 160- and 200-mm.fluid-bed pilot roasters. Laboratory results indicated that the maximum gold extraction was 92%, with the head and the leach residue containing 5.7 and 0.4 g/t (0.166 and 0.013 oz/st) Au, respectively. The maximum extraction was achieved under the following roasting conditions: a top particle size of 150 yin, a residence time of 2 hrs, a roasting temperature of 475°C and with 40% oxygen (by volume) in the off-gas. Similar results were obtained from circulating fluid bed (CFB) pilot-plant testing. The maximum gold extraction was 90%, with the head and leach residue containing of 5.1 and 0.5 g/t (0. 149 and 0.015 oz/st) Au, respective) v. These results were achieved with the same particle size and oxygen concentration as in the laboratory testing but with the roasting temperature of 500 ° to 525°C and a residence time of 30 min.

Jan 1, 2000

By Brian P. Canning

Ion exchange resin processes are receiving renewed attention in the mining industry for recovery;, of metals from solution. This interest has been inspired by the development of continuous countercurrent ion; exchange systems (CCIX) which are of much lower cost than the original, fixed bed contactor processes. With the countercurrent systems and new developments to process or upgrade the eluate product, ion exchange can now compete successfully with solvent extraction for treatment of uranium ores. The low concentration of U308 obtained in the CCIX strong eluate is generally upgraded by solvent extraction methods in sulfuric acid systems. Resin loadings of up to 120 grams per liter of U308, however, have been produced experimentally by recycling of eluate (HIM-IX process) and further developments may be expected in the near future. New developments in resin technology are bringing forth products of greater strength, loading capacity, selectivity and density. Densities up, to 1.35 spgr have been claimed by some suppliers. The process is not a new one and has taken years to advance to the present state of development. The earliest system to gain widespread acceptance was the resin-in-pulp system applied to uranium recovery. Ion exchange, however, later lost acceptance in favor of solvent extraction in the 1960&apos;s due to problems in resin degradation, resin contamination and resin-pulp separation, in addition to the development of improved solvent extraction reagents and techniques. The resin-in-pulp system continues to have application on high clay ores and has advanced in design. A number of other continuous ion exchange systems were also tried but never gained continued acceptance. In the current resurgence period the CCIX systems to gain acceptance were the Utah and Chem-Sep (Higgins Loop) systems. These processes are relatively simple in concept although require sophisticated controls. Fixed bed columns have also been designed into multistage systems in countercurrent operation but are not discussed in this paper. These systems remain competitive today for many applications. The most recent advancements however have been in the multistage contactors from,, which three are in current acceptance. These are the Himsley, Porter, and NIM systems. All industrial applications of these systems are relatively new, although pilot plant and in-plant development has been in progress over the last decade. Fur36ther developments should be expected in the near future.

Jan 1, 1979

By Fathi Habashi

ION FLOTATION was introduced by F. Sebba in 1959. This technique permits the recovery of metal ions from solution through the introduction of an appropriate cationic or anionic surface-active agent into the solution. The surface-active agent, called a collector, is added in stoichiometric amounts in relation to the metal content of the solution. It reacts with the metal ion to form an insoluble soap, and is levitated to the surface by gentle bubbling of air to form a foam which collapses into an insoluble scum. The optimum conditions for the ion flotation with soaps of C10-16, fatty acids are shown in Table 15-1. Baarson and Ray (1965) found that once the metal was completely precipitated as the hydroxide, as little as one hundredth the stoichiometric amount of the collector was required to cause complete flotation of the [ ]

Jan 1, 1970

By John P. Capp

In recent years limited markets have been developed for fly ash, the dust removed from coal-burning powerplant stacks, but most of it is still dumped in spoils areas at a cost ranging from 20 cents to $1.75 per ton. Aside from this cost, the creation of huge spoils areas can present a considerable aesthetic problem. Since the present annual fly ash output of about 20 million tons will probably reach 30 million by 1970, and because satisfactory disposal areas are becoming more limited, markets for much larger quantities of the waste are needed to keep disposal costs from becoming a significant economic factor in coal-burning powerplant operation. Current stress on air-pollution control and beautification, plus the vital need for good powerplant economy, makes it imperative, therefore, that coal producers and consumers expand markets and develop new applications for fly ash. Markets for established uses can be increased by making a greater effort to sell fly ash. New large tonnage markets for fly ash should be sought via more intensive, coordinated research. The economics of fly ash utilization underscores the vital role that must be played by research. To be competitive with other products, processes for the conversion of fly ash into marketable materials face difficulty in regard to two important economic factors--transportation cost and product utility--the other economic factors are favorable. Raw material costs of fly ash, for example, are quite attractive, and supply is no problem because there are many coal-burning powerplants in operation and many more are planned. Demand for products made from fly ash will grow if their utility is established and a good sales program is initiated. The major problems then are transporta¬tion costs and development of useful products.

Jan 1, 1966

By C. Tom Blevins

LADIES AND GENTLEMEN : This presentation is to discuss production and roof control problems associated with directional lateral stresses in an in situ stress field and the approach that Inland Steel Coal Company made in trying to cope with them. Before proceeding, a brief description of the mine location, product, geology, restraints, and mine history is in order.

Jan 1, 1982

By K. Y. Haramy, B. T. Brady

A scale-invariant theory of the strength and deformability, of rock masses in static equilibrium and at incipient failure is proposed The theory provides a rationale, for designing structures in rock. This paper presents results of experiments conducted by the US Bureau of Mines and presents theoretical methods to determine and interpret the in situ strength of rock masses using the borehole shear tester.

Jan 1, 1996

By Harry Perry

The decline in coal production has been slowed somewhat in recent years, mostly because of the industry&apos;s own remarkable success in holding the line on costs, and partly as a result of advances achieved through industry and government research. Nevertheless, the decline has continued. This downward trend combined with the increased productivity of labor through mechanization that has been necessary for coal to retain even its present competitive position, has resulted in a serious reduction in the number of miners required and large scale economic dislocations in mining communities. For coal to regain a more favorable position it must either expand existing markets by reducing the cost of the delivered product and thereby compete more effectively with other fuels or develop new uses that will require large tonnages of coal. New markets involving several million tons, which would look extremely attractive to most other United States industries--including the organic chemical industry--would do little to alleviate the coal industry?s depressed economic conditions, While such small new markets would be welcome, an industry producing over 400 million tons per year must look to large tonnage outlets for solutions to its long range economic problems.

Jan 1, 1964

By Gopalan Ramadorai

This paper presents a review of halogen solvents used in the processing of precious metals. Reagents of widely varying chemical structures, such as chlorine gas, calcium and sodium hypochlorite, chlorine dioxide, iodine and bromine have been used for precious metal extraction. None of these chemicals are a replacement for cyanide: however, each of these chemicals present an opportunity for use in processing a specific type of ore. The ore and chemical must be matched to each other for success. Recovery of metal from the leach solutions also offers challenges.

Jan 1, 1994

By Keith S. Olsen

Any discussion of barite mining is virtually impossible without considering, almost in the same breath, the many other variables, such as beneficiation, transportation, infrastructure and location that impact the economics of a particular barite orebody. My comments will be limited to just the mining aspects of barite orebodies and these observations must be considered in proper context with all other parameters affecting exploitation of a barite property prior to final decision on economic feasibility. In many instances low-cost mining situations are more than offset by high-cost beneficiation requirements. Likewise, there are cases of relatively high-cost mining associated with no or low-cost beneficiation requirements thus permitting economic exploitation. Barite orebodies and occurrences are almost as varied as the number of occurrences. As in most mining situations, the design of a mine plan and implementation of a proper exploitation program must be approached on a case by case basis. Proper and sufficient geologic control of a barite orebody must precede the development of a mine plan. Generally speaking, barite orebodies can and, at many times, do "strange" things; pinch with depth; almost never increase in size with depth, overturn, fault-off, change grade, etc. Due to the extreme variable nature of most barite orebodies, a mine plan and its implementation must be as flexible as possible. The ability to quickly adapt to variable conditions will greatly enhance the economics within a particular barite mining environment.

Jan 1, 1980

By B. Kolonja

This paper considers simulation of truck dispatching system designs using maximum expected production of the truck-shovel system as the measure of performance. Two methods are utilized, multiple comparisons with the best (MCB) and the combination of MCB and the variance reduction technique known as common random numbers (CRN). These two techniques are compared via simulation experiments. The results show that the combined procedure of MCB with CRN is the superior tool to reduce the total number of replications needed to ensure the specified probability of correct selection over the finite number of designing systems. In this case study, MCB with CRN reduces the variance by 29% and the number of required replications by 48%. Also, the MCB with CRN procedure narrowed the confidence interval by 18%.

Jan 1, 1994

By Stephen H. E. Phillips

Geological and hydrological conditions in the strata overlying the Salado Formation vary considerably in the Carlsbad, New Mexico area. The first four shafts sunk at international Minerals and Chemical Corporation&apos;s property have been located in competent and essentially dry conditions, while other shafts on adjacent properties have had such adverse conditions that ground freezing has been chosen as the water and ground control technique for shaft sinking. At the location of the IMC No. 5 Shaft there has been extensive-erosion and salt dissolution in the Rustler Formation which has led to collapse of some zones of the strata. Both ground freezing and pregrouting were considered as alternative methods of stabilizing the extremely poor ground conditions and controlling the potentially very heavy water inflows it was decided that pregrouting the shaft was feasible and would offer substantial cost and time saving over a ground freezing technique. This paper describes the pregrouting techniques used and illustrates the requirement for flexibility in a grouting program so that it can be codified to reflect any new or additional information which is obtained during the progress of the grouting.

Jan 1, 1984

By Robert E. Frey

Regardless of the mechanical design features of a particular air classifier certain basic principles apply. Specifically , there are two forces at work: 1. An air drag force 2. An inertial or centrifugal force. The air drag force has an increasing influence as particles become smaller. A very small low mass particle is easily carried along with an air stream even when turning a corner. Thus, fine particles follow the air away from the classifying zone. Inertial forces increase as the mass of a particle gets larger. Thus oversize particles tend to obey Newton&apos;s laws and respond to centrifugal forces or simply continue in a straight path when the airflow changes direction.

Jan 1, 1985

By Lorraine B. Burgin

The extensive lead time to develop most Arizona copper deposits commenced with initial production efforts before the turn of the century, when the first attempts were made to recover gold and silver and later copper from the high-grade vein deposits of the territory. Each of these discoveries, prospects, and early operations had its own lead time and life cycle as economic production was attempted. Because prices of the metals fluctuated and the higher grade material was depleted, economics forced operations to close and companies to fail. Renewed interest in the property because of improved conditions, different interpretation of the geologic structure, or new promotional ability frequently resulted in the formation of yet another company to finance the exploration and, hopefully, the development of the property. This cycle of renewed activity and subsequent abandonment was and is common, accounting for many lead times and for the long period of time from the initial location of claims to large-scale production. In order to gain a perspective on the lead-time interval necessary to achieve development of a large-scale operation, the histories of several major Arizona mines were examined, rather than a simple listing of discovery and production dates of many mines to arrive at a statistical average. The Miami, Castle Dome, Copper Cities, San Manuel, and Twin Buttes properties were studied, and as much data as possible obtained on the Pinto Valley, Esperanza, Sierrita, Pima, and Mineral Park-Ithaca Peak properties.

Jan 1, 1974

By John J. Mulligan

Coal is found in every major geographic region throughout Alaska and in two offshore areas. Since about 1852 over 100 small mines have opened and closed. Last years production was almost entirely from one mine in central Alaska. Clearly the utilization of Alaska&apos;s abundant coal resources presents political, economic and technical problems that are far from solution. Location and Physical Features Figure one illustrates the geographical and geological similarity between Alaska and western United States. The Arctic region of Alaska generally resembles Wyoming and the Dakotas. The Brooks Range is an extension of the Rocky Mountains. The Central region of Alaska between the Brooks Range and the Alaska Range bears a general resemblance to the basin and range country of western United States. The Southcentral and Southeastern regions has a similar resemblance to the Sierra Nevadas and the west coast of the United States.

Jan 1, 1982

By A. D. S. Gillies

The effectiveness of coal mine face ventilation and the ability of air flow to maintain satisfactory methane and respirable dust levels in the working face area has been studied through the use of scale modeling techniques and underground testing procedures. In particular, consideration has been given to examination of the effects of operation of a high air flow machine mounted dust scrubber unit on face air patterns. Results obtained through a cooperative study with the Peabody Coal Company demonstrate that new mining cycles can be considered which increase production efficiency while maintaining satisfactory ventilation conditions.

Jan 1, 1982