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By G. S. Dobby

High-intensity wet magnetic separators have been successfully introduced into the mineral processing field over the past ten to fifteen years, due largely to rapid advancements in magnet design. Wet magnetic separation, until recent years, was applied solely to the concentration of minerals of high magnetic susceptibility, such as magnetite, at relatively coarse sizes. Now, however, high-intensity separators are capable of treating weakly paramagnetic minerals and have extended the range of treatable particle size down to about one micrometre(1,2). . One of the more recent-high-intensity separators developed is the Kolm¬Marston Marston type high-gradient magnetic separator (HGMS) (3,4) It consists basically of an iron-clad solenoid surrounding a matrix material - a fine, ferromagnetic steel wool or expanded metal lath. A schematic diagram of the device is shown in Figure 1. Large, highly localized, pertebations of the magnetic field are created by the ferromagnetic matrix. It is these field gradients that are instrumental in developing large magnetic forces which act on the mineral particles. Operation of the separator is simple. Slurried sample is fed through the matrix and, depending upon the mineral parameters of particle size and magnetic susceptibility and. the operating parameters of flow rate, field strength and feed weight, some particles will be attracted to and adhere to the magnetized matrix, while the others will flow through the matrix. The separation is completed by later removing the background magnetic field and flushing the captured mineral particles into a separate container. The process can also be applied on a continuous basis (S).

Jan 1, 1977

By M. J. Blattman

The problem of measuring the amount of rock removed during a given time interval is faced by most milling operations. Many methods have been developed with varying degrees of success, dependent upon the mining method and the availability of usable data. The Rosebud Mine has been in production for nearly two years, employing several techniques to estimate monthly production from underground production stopes. The use of three-dimensional solids generated from survey data has greatly improved the reliability and confidence of monthly production reports. The authors will summarize the methodology currently being utilized at Rosebud.

Jan 1, 1999

By N. P. Reddy

This paper describes an experimental setup for multiple-fan ventilation systems at the ventilation laboratory of the WVU Department of Mining Engineering. Housed in a 30 ft by 70 ft room, the experimental setup consists of three 18 in. variable-speed axial-flow fans, the 18 in. diameter fiberglass tubing and fittings for arranging networks, and the pitot tube measuring and data acquisition system. The fiberglass tubing and fans can be organized into the non-planner network of two fans or three-fans. It is mainly designed for studying the characteristic curves, operating points, and fan stall for the multiple-fan ventilation system.

Jan 1, 1992

By C. Bailey Williams

Aragonite "sand," an oolitic lime-stone, is distributed throughout the Bahamas on the Grand Bahama Bank, adjacent to Southeast Florida. Bahamian deposits hold 75-100 billion tons of recoverable Aragonite. Aragonite's precipitation from seawater over 700 years ago assures low contaminates, making it a pure material for such industries as cement, glass, etc. A 90-acre, man-made production island was built south of Bimini, adjacent to ocean shipping channels mining is by cutterhead, suction dredge, dewatering, and stockpiling for further drainage and shipping. Aragonite is transferred to the U. S. East and Gulf Coasts via bulk carriers to points of sale.

Jan 1, 1978

By John E. Young

United States Steel Corporation's Winifrede Mine is operated by Lynch District in the mountainous region of Eastern Kentucky. This region is characterized by narrow mountain ridges and precipitous slows which present both an opportunity and challenge in the design and selection of coal handling facilities for the movement of coal from the section belts to the railroad cars. The narrow finger ridges precluded use of underground haulage and, thereby, presented the opportunity to use high capacity equipment on the outside bench. The precipitous mountain slopes, steepest at the Winifrede seam horizon, presented a challenge to select a solution for lowering the coal approximately 1000 feet from the seam level to the valley floor railroad load-out point. It was evident from the start of planning that these two factors predominated; namely, rail haulage and coal lowering, and solutions to these would determine the final design of the Winifrede Mine coal handling facilities.

Jan 1, 1970

By D. Baker

Alternative material handling methods are allowing material handling operations to be performed with increased cost savings. This allows for higher production levels with better returns. RAHCO International Inc.'s Continuous Mining Excavator (CME) has recently received a lot of attention due in part to its operating efficiency, flexibility, and associated low operating costs. The CME is designed to perform three primary functions. These include material excavation, sizing and loading operations. In many applications, a drilling and blasting process can be eliminated. The CME was developed originally in 1985 for open pit coal mining. See figure I. Since this time, it has been proven an effective system for excavating many other types of materials including friable and sticky materials. It has also been shown to suitably handle hard rock in certain site conditions.

Jan 1, 1998

By Jonq-Keh Lee

This paper deals with the effects of air leakage from intake to return airways through a series of stoppings on the analysis of coal mine ventilation. The mathematical model which assumes continuous leakage along adjoining intake and return airways is reviewed, and a new mathematical approach is presented based upon the concentrated leakage through individual stoppings. The procedure incorporating the new method in the analysis of coal mine ventilation networks is also discussed.

Jan 1, 1984

By George M. Hamilton

The gas producer actually dates back far beyond the period from which we first find recorded data. A partial production of producer gas can take place in any type of solid fuel grate equipment, such as a boiler, or even a fireplace if a sufficiently deep fuel bed is provided. Those of us who have watched a coal fire burning in the hearth, have no doubt noticed at times, the gases liberated by the heat burning on or near the surface of the fuel bed. So far as we know, the first gas producer was built by Bischof in Germany in 1839, followed by Ebelman in France in 1840, and Ekman of Sweden in 1845. The first large industrial development in the use of gas producers was When the two Siemens brothers of Germany patented their first combined gas producer and regenerative furnace in 1861, thus opening up the field for the use of raw, crude producer gas in heavy furnace work. In the years 1879-1881 J, E, Dowson, of England developed a producer gas cooling and cleaning plant, which extended the scope of application of producer gas to make possible its use in small furnaces and gas engines.

Jan 1, 1961

By N. Arbiter

Evidence for the floatability of sulphide minerals without collector is analyzed and it is shown that results obtained with ores, in contrast to those with single minerals or mineral mixtures, depend on many additional variables, some identified and others not. Because of the prevailing low levels and costs of collectors for most sulphide ores, it is unlikely that collectorless flotation will have commercial applications, so that continued research on the subject may be justifiable on theoretical but not on practical grounds.

Jan 1, 1993

By A. A. Campoli

A stress control design strategy was developed to minimize the explosive failure of highly stressed pillars, during room-and-pillar retreat mining conducted between stiff immediate roof-and-floor strata. A confined core coal pillar strength model was based on in-mine geotechnical evaluations of successful room-and-pillar and longwall bump control designs. Tributary area and linear shear angle approaches were used to estimate development and gob side abutment pillar loads for supercritical section widths. Subcritical width sections separated by barrier pillars to control stress within total extraction panels were optimized with the boundary element program MULSIM/NL.

Jan 1, 1994

By J. R. Mackie

Reserve Mining Company, the first large-scale taconite pellet producer in the United States, mines it's crude ore at the Peter Mitchell Mire located on the eastern end of the Mesabi Iron Range near Babbitt, MN. The ore is processed at Reserve's beneficiation plant on the north shore of lake Superior at Silver Bay, M. The mine and plant are linked by a 47 mile, double track, railroad which is owned and operated by Reserve. (see Fig 1). At rated capacity, the mine can produce 33 million It/yr of crude ore, 15 million It/yr of waste rock and 1.0 - 1.4 million yd3/yr of glacial till stripping. Haulage of all mined material is accomplished using trucks. Ore is transported by tractor-trailer side dump units which have capacitys ranging from 83 to 110 long tons. Waste rock and glacial till is transported in end dump units of 50 to 120 LT capacity. Loading is accomplished by 11/13 yd3 power shovels and 7/10 yd3 front-end loaders.

Jan 1, 1985

By Eugene L. Foster

The engineering profession has traditionally devoted its efforts to understanding and modifying the Earth's environment in order to adapt it to man's needs. In appraising our overall performance, I would have to say it has been a mixed bag. In many areas, notably communications taken in the broadest sense, and development of creature comforts, we have done a good job. In others, we have failed, particularly in our assessment of the effect of our work on the environment. Our failures have been due in part to a lack of understanding or foresight, and in part to a disproportionate emphasis on lowest first cost. Now, with an increasingly large number of people living in a finite environment, there is an urgent need for reassessment. It is no longer possible to pursue a single objective without regard to its side effects. Our projects are too large, and there are too many of them. Environmental impacts must be taken into account in all important engineering decisions of the future. There are forces at work which will help to bring this about. Thinking people everywhere have realized that adverse alteration of our environment eventually affects every one of us. The majority of our citizens, who now live in cities, are beginning to appreciate the advantages of a good natural environment in a way which others who have been closer to the soil have appreciated for years. Our people have flocked to the cities because they wanted to be "where the action is." At the same time, there is a strong desire for what we have come to call the quality of life. Today, we all want the standard creature comforts. We want to be able to move freely

Jan 1, 1974

By O. M. Wicken

Magnesite has the unique combination of properties that make it useful in a wide variety of metallurgical applications. The use of refractory magnesite has been increasing throughout the world, but the source of the "ore" differs. The United States has increased production of synthetic magnesites while the rest of the world is exploiting its resources, using natural magnesites. The history and methods of manufacturing synthetic magnesite are discussed as well as the practices for beneficiating natural magnesite. The properties, costs, and uses of the two types of magnesite are discussed and compared.

Jan 1, 1964

By T. H. Eyde

Natural Zeolites are a less expensive and in certain applications a superior alternative to organic ion exchange resins. Mining and metallurgical waste streams are difficult to treat because the effluents which contain potentially valuable heavy metals such as copper, lead, and silver are often highly acidic and contain significant quantities of suspended solids. Under rigorous operational conditions, certain natural zeolites can remove the metals, which if desired can be recovered by either elution or conventional smelting techniques. There are significant differences in cation exchange rate, selectivity and capacity as well as resistance to either high or low pH, blocking cations and tolerance to elevated or depressed temperature and pressure not only between different zeolite minerals but between the same mineral from different deposits. Applying natural zeolites to the treatment of mining and metallurgical waste streams depends on matching the specific zeolite to the effluent by characterization of the zeolite minerals.

Jan 1, 1994

By Karin Bäppler

"When considering large-scale infrastructure projects worldwide special attention has to be paid to the large diameter tunnel construction projects that were successfully completed in the Southern Hemisphere. The projects that are highlighted in this paper are large-scale infrastructure projects in the sector of transport. In focus are four road tunnel projects that were constructed in Australia and New Zealand using mechanized tunnelling technology. The tunnel boring machines (TBMs) that were reliably applied to these four major projects all exceed the bore diameter of 12 meters. These TBMs are therefore in the range of large to very large diameter TBMs. The technology used demonstrates state of the art technology with tailored tunnelling technology adapted to the specific project demands. Two Double Shielded Hard Rock TBMs (Ø 12.35 meters) were used for the construction of the Clem Jones Tunnel in Brisbane crossing beneath the Brisbane River and these two machines have been reused for the excavation of a 4.3km long two-lane highway tunnel for Legacy Way in Brisbane creating a new traffic artery towards the city centre. Two EPB Shields (Ø 12.48 meters) excavated and lined the twin-tube road tunnel for the Brisbane Airport Link. Excavation diameters in excess of 14 meters, such as the Earth Pressure Balance Shield (Ø 14.41 meters) involved in the Waterview Connection Project in New Zealand, are understood in the tunnelling industry as very large diameters. The machine is customized to the requirements and subsurface conditions of Auckland. The paper spotlights the large to very large diameter TBMs that were used and focuses on the comprehensive solutions developed by the machine manufacturer to provide a system with benefits for the contractor especially for the Waterview Project. INTRODUCTION Extensive large-scale road infrastructure projects like the ones implemented in Brisbane (Australia) and currently under construction in Auckland (New Zealand) show the tendency of today’s infrastructure construction projects. Functional infrastructures need to be put in place to cope with the demand of mobility and flexibility of people living in cities and metropolises. Impact during construction work to people or environment has to be kept as low as possible to ensure the quality of life is not disrupted."

Jan 1, 2016

By G. F. Joklik

Although the mineral shortages of twelve to eighteen months ago have given way to oversupply, their memory lingers on. These problems were man-made: booming demand throughout the industrial world, political and industrial unrest and the oil embargo all contributed. But in the minds of many, the shortages conjured up visions of the depletion of the world's mineral resources, a disaster that could be staved off only by drastic curbs on consumption and therefore, curbs on economic growth. A little historical research shows that fears such as this are not inventions of the 1970's. A hundred years ago, for example, the imminent exhaustion of the world's coal supplies was being predicted in Great Britain. The English economist, John Stuart Mill, who was usually more perceptive, wrote a few years earlier that "it is only in the backward countries of the world that increased production is still an important object". And later there was Franklin Roosevelt who said in 1932, "Our industrial plant is built; the problem just now is whether under existing conditions, it is not overbuilt". His concern, in other words, was not with the discovery and exploitation of new natural resources, but with the administration of known resources and with seeking foreign markets for surplus production. In light of copper prices at the time -- just under 6¢ a pound -- that was understandable. These instances illustrate how, throughout the world's industrial history, concern about surpluses of raw materials has alternated with alarm about the adequacy of supplies and with calls for restricting growth.

Jan 1, 1975

Conventional logging tools such as density, neutron, and acoustic have ranges of investigation of tens of centimeters. The borehole gravimeter, however, has a range up to hundreds of meters. For example, from the center of a cylindrical orebody 0.22 g/cm3 denser than its surroundings, one can detect the boundary of the orebody at a radius as large as five times its height. More complex structures can be investigated with computer programs. We can predict the usefulness of proposed gravity surveys, or decide which suggested structure is most likely to have caused the results of existing surveys.

Jan 1, 1985

By A. B. Holland-Batt

Following a relatively static period in the 1960s and 1970s when incremental development rather than innovation was the norm for gravity separation, the last 15 years has seen a number of new developments in this area. The paper briefly reviews the traditional gravity separation techniques and then examines the newer developments such as centrifugal separators. Particular emphasis has been placed on novel devices or improvements that offer either better control or improved performance.

Jan 1, 1998

By William F. Abercrombie

The role of the laboratory is described in relation to the prospecting and exploration of kaolin clays. Test methods used to evaluate crude ore samples of kaolin clay for commercial consideration are reviewed. A background of the kaolin mineral and known means of prospecting this mineral are presented. Common analytical methods are discussed with special emphasis on those in use today.

Jan 1, 1982

Gold cyanide equilibrium adsorption isotherms in the loading range typical of operating carbon-in-pulp/carbon-in-leach plants have been established and the effect of various cations and the presence of copper cyanide species quantified. It was found that the equilibrium loading of gold was enhanced by the presence of sodium or calcium, with calcium having an order of magnitude stronger effect. The presence of copper has an adverse effect on the equilibrium loading of gold. A unified model was developed to predict the effect of sodium and calcium concentrations in solution and the competitive carbon adsorption of copper on the equilibrium loading of gold on carbon. A satisfactory agreement between the measured gold equilibrium loadings and the model results was obtained over a wide range of solution conditions.

Jan 1, 2010