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By B. Caines

Much of the mining industry in North America is in a crisis state. Host producers are operating at production levels well below capacity, some have been merged or sold, while others have been mothballed or closed permanently. For many of us still operating, the future is uncertain. Despite the many cutbacks and closures, there is still an abundant supply of minerals in the world market and there is almost no hope for any relief on price pressures on most mineral commodities in the near future. The Iron Ore Company of Canada (IOC)operates an iron ore mine, a concentrator and a pellet plant known as the Carol Project located in Labrador City, Newfoundland. This concentrator and the pellet plant have the annual capacity to produce 20 million and 10 million tons respectfully. A company owned and operated railway links this operation with the dock terminal facilities in Sept Iles, Quebec.

Jan 1, 1987

By John R. Riede

The use of radioactive gages in beneficiation plants is relatively new However, enough applications have been made so that it is now possible to positively state that these gages have definitely progressed from a laboratory device to a very rugged and reliable on stream process measuring instrument. Gamma Ray Gages of the type presently being used in the beneficiation industry consist of three basic components: (1) A source of radiation (2) A radiation detector (3) An electronic amplifier The source is usually a radioisotope such as cesium-137, or cobalt-60. This source, adequately protected and ruggedly mounted, is most commonly placed on one side of a pipe or vessel. The radiation detector is then mounted on the opposite side, Since the absorption of gamma radiation as it passes through various materials is a function of the density of the material, the change in radiation measured by the detector is proportional to the change in specific gravity of the product in the pipe or vessel. One popular type of detector in use today is a cell which converts radioactive energy directly into electrical energy1. This electrical energy, when amplified, presents a usable output for metering and control devices. There are, of course, many other components which are part of a working gamma gage installation, such as zero compensators, lead shielding, mounting brackets, equivalent absorbers, etc.

Jan 1, 1958

By James W. Mahar

The following paper summarizes our observations on building response to mine subsidence and techniques for mitigation of building damage. The subsidence cases are located in Illinois. The general description of the geologic and mine conditions are primarily for those sites. Data on building response and mitigation measures were collected under grants supported by the Abandoned Mined Lands Reclamation Council (AMLRC) of Illinois and the U. S. Bureau of Mines, in Twin Cities, Minnesota. Case histories include pit and sag subsidence primarily beneath abandoned room and pillar mines. The majority of the paper deals with structures affected by sag subsidence. Most of the structures are one and two story homes. The first section of the paper summarizes the typical geologic and mining conditions at the sites. Building response to pit and sag subsidence follows the first section. Emphasis is placed on the behavior of concrete and masonry foundations, and wood frame and masonry superstructures. The third section describes mitigation techniques used to prevent or minimize building damage. A summary of the observations and critical parameters is given at the end of the paper.

Jan 1, 1982

By Michael R. Birkos

A new electrotelluric prospecting technique allows the mapping of ore body distribution, lithologic contacts, and voids with accurracy comparable to core drilling. Data is available almost immediately and presented in a format similar to a downhole log. This is done with a passive surface receiver that transduces electrotelluric radiation into an audible signal. Changes in the character of the audible signal lends insight into lithology, porosity, fluid type and medium. Three case histories are presented. The first delineated a paleochannel within a coal seam. The second traced old mine workings and backfill areas. The third identified a high-pressure karst void.

Jan 1, 1986

By M. F. Corcoran

Rapid advances have been made in the past few years in the application of automatic controls and instrumentation to iron ore pelletizing plants. Present practice in applying instrumentation and control to the Grate-Kiln system of iron ore pelletizing is described. Major control points and loops are tabulated. Future trends in the application of digital control including computer data logging systems are described.

Jan 1, 1965

By T. D. Kaufmann

When Dr. David Gully solicited this paper last spring a few questions basic to commodity trade between the U.S. and world markets appeared perplexing. Why, for example, when the demand for aluminum was at a peak and when little expansion of capacity had taken place, was the dollar price half of what it had been at the previous peak? Or, why in 1984 when imports surged by 50% as the U.S. economy pulled out of its recession did the dollar not fall, but rather rose by 35%? And, why when the experts all seemed to agree that the dollar was grossly overvalued did the price of gold continue to decline? Surely these were extraordinary times for the mineral economist. When this paper was written in late July, 1985 the answers seemed clearer. The prices of many commodities were not low - the dollar in which they were denominated was too high. In other currencies many commodity prices were indeed high. The dollar was overvalued in trade terms by some 40% caused by an influx of short term coupon investments made by foreign money managers to take advantage of the higher short term interest rates in the U.S. relative to other international banking centers. With a decline in the relative difference in interest rates, an unhealthy buildup of foreign bank accounts and a perception that the dollar would fall, the dollar did start to decline rapidly.

Jan 1, 1985

By Charles E. Weaver

A core from the La Camelia attapulgite mine in north Florida was studied in detail to determine the detailed vertical variability and the relations of the various parameters. The structural, textural, mineralogical and chemical data indicate there are two major depositional cycles represented within the minable interval. The sediments deposited during the two cycle differ in detail but in general are similar. The environments of deposition grade from shallow marine to lagoonal to tidal flat to marsh. The sedimentary structure (lamination, burrows, pebble conglomerate), mineralogy (attapulgite, montmorillonite, sepiolite, dolomite, calcite) chemistry (Al, Mg, Fe) are closely related to each other and their nature is determined by the depositional environments. Most of the clay minerals and carbonate minerals are authigenic and are therefore particularly sensitive to environmental differences. The variability and environmental features seen in this core are characteristic of the sediments in the general attapulgite mining area. A detailed understanding of the relationships discussed should be of value in prospecting, mining and processing.

Jan 1, 1972

By J. L. Vanderbeek

The SAG milling of ores with markedly variable grinding rates presents definite process control challenges. Decisions must be made regarding the selection of the most appropriate combination of mill volumetric load level, percent solids, and mill speed for the combination of ore types being processed at the moment. An investigation was performed concerning the effects of these parameters. General results are presented.

Jan 1, 1985

By M. A. Bouchat

The Kipushi deposit, where the Prince Leopold Mine has been installed, belongs to Union Miniere du Haut-Katanga and is located in the Belgian Congo, 20 miles SW of Elisabethville, at the vicinity of the Northern Rodhesian Border. The deposit is of the hydrothermal metasomatic vein-type; mineralisation took place, through the limestone of the, lower Kundelungu. This is a special fea¬ture of the deposit, compared to the other copper deposits of the neighbourhood, both in the. Belgian Congo and in Rhodesia. Actually, the primary mineralisation of these other deposits; is directly related to the stratigraphic systems: schistous dolomitic in the Belgian Congo and Roan in Rhodesia. Both facies are older than the Kundelungu and separated from this formation by a tectonic cataclysm. The valuable elements occuring at Kipushi are principally copper; and zinc. The deposit also contains smaller quantities of lead, precious metals and other elements including germanium.

Jan 1, 1960

By W. Ghyoot, J. Boonstra, H. Dijkman, C. Buisman, M. Picavet

Paques and Umicore have demonstrated the feasibility of biological treatment of the highly complex Hoboken wastewaters in a1 m3/h pilot plant at Umicore Precious Metals, Hoboken, Belgium. In the first step arsenic was precipitated from copper smelter effluent as As2S3using biogenic produced H2S. Other metals such as copper, lead and cadmium were also removed as MeS to concentrations well below the discharge levels. Subsequently, sulfate and nitrate were removed to low concentrations (<300 mg/l and < 5 mg/l respectively) in high rate engineered bioreactors. Sulfide produced in the sulfate reduction process was recycled to step 1 for metals precipitation. Selenite/selenate was partly removed in the sulfide precipitation step, whereas the excess was biologically reduced and removed as selenium to concentrations <0.2 mg/l.

Jan 1, 2003

By J. J. Schwoebel

Resource Enterprises, Inc. (REI) is exploiting the coalbed gas resource by working in unison with active underground mining operations. At REI?s pilot project at the Soldier Canyon Mine, Carbon County, Utah, REI has drilled nearly 15,250 m of horizontal in- seam and slant boreholes during the initial two years of drilling activity. Produced gas has been sold to a natural gas transmission company on a continuous basis since mid 1983.

Jan 1, 1986

By Robert L. Vines

"What is past is prologue" - motto of National Archives The question of past, present, and future safety performance in the coal mining industry is not merely an academic one, or one which arises from soul-searching curiosity. It is a question involving pragmatic ramifications, and the answers, or perhaps the public perception of the answers, will have a strong impact on the public policies which influence the course of meeting the Nation&apos;s future energy demands. Those of us in the coal industry are keenly aware of the significant impact of the public reaction -- in the form of the 1969 Health and Safety Act -- to -past performance of the coal industry which it found unacceptable. That Act was revolutionary -- and it was expensive. But in finding the industry&apos;s past performance unacceptable, the public also recognized its own contributory role through having enjoyed a "buyer&apos;s market" forced on a highly competitive industry. One result was to limit the industry&apos;s resources and restrict its ability for self-improvement of its safety performance. In acknowledgement of that role, the public picked up the tab for Black Lung disability incurred prior to that time.

Jan 1, 1985

By Lee A. Goetz

Cost control is a lot like motherhood - everyone proclaims its need and its worthiness, but is it really appreciated and used to successfully complete a project on time and within budget? Good Cost Control is a yardstick - requiring fixed definition but this does not mean rigidity for the project. It provides the means for telling: 1. Where you are going 2. When you will complete and 3. What it will finally cost. Cost Control does not fix the price of dreams nor the cost of projects loosely defined. It does not control costs in itself but provides the tools whereby engineering decisions can be made which will ultimately affect the project cost It does not even guarantee that a project will be completed within the original funds - but only, if this reflects management desires.

Jan 1, 1970

By Erwin K. Roesner

The difficulties encountered while sinking deep shafts for Potash Mines in southern Saskatchewan have been the subject of several papers in the past. Geological and hydrological conditions of the strata overlying the potash deposits require special techniques for ground and water control during shaft sinking. The easily soluble potash ore requires the lining of these shafts to be virtually watertight to assure long term and safe operation. This paper describes the construction of the most recently completed potash shaft for the Potash Corporation of Saskatchewan. The shaft was designed and constructed by Thyssen Mining Construction of Canada Ltd. and it is located near Lanigan, approximately 110 km east of Saskatoon.

Jan 1, 1980

By S. A. Bortz

IIT Research Institute has initiated several multi-sponsored research programs. In this paper the methods for developing four of these programs are discussed. In general, a broad area of investigation must be proposed to interest a spectrum of different industries. The work must not touch upon proprietary data and will probably involve a number of scientific disciplines. Thus, the problem to be solved will attract sponsors who need to know more about the area under study but do not wish, as a single company, to commit the resources required to obtain the necessary know-how for their needs. The paper draws on the background of four IITRI multi-sponsored projects: Size Reduction, a study of grinding of material to reduce their particle size; Melt-Formed Ceramics Research, a method of producing dense, polycrystalline ceramics using glass forming methods; Binders in Ceramic Processing, which addresses the problems associated with the use of organic aids for ceramic processing; and a Study in Air Pollution Technology, a program to review and assess pollution control equipment for current and future applications.

Jan 1, 1984

By G. A. Hufford

The cutoff grade applied to a disseminated orebody mined by open pit affects both the waste ratio, hence the cost of producing ore, and the ore grade, hence the quantity of metal recovered. As such it has a significant impact not only on the annual profit or loss, but also on the life of a mining property. Cutoff Grade Strategies Some commonly used objectives in calculating cutoff grades are as follows: Minimize Unit Cost of Product (1) This is found by adding all costs associated with each possible cutoff such as mining, processing, and marketing. This is divided by the quantity of marketable product obtained at each cutoff grade, then finding the minimum. Because the market value of the product does not enter the calculation it has no effect on this strategy: the same cutoff is selected in good times and bad.

Jan 1, 1986

By Paul Soros

The rationale for innovations in two directions is identified: raising capital and annual throughput, in order to avoid the cost of constructing and operating an additional system and to reduce the capital cost of pits and tunnels, applicable to installations of any capacity. Cast histories cover railroad unloading of bottom dump cars, rotary dumping of random cars, with and without indexer, and unit trains as well as truck unloading of multiple grades of coal.

Jan 1, 1985

By R. O. Vernon

The Florida Peninsula has existed as a part of a much broader plateau, since at least the Early Cretaceous. This plateau, the Floridan Plateau, now consists of the present peninsula and a broad submerged shelf of equivalent size extending the length of the state and out into the Gulf of Mexico. Florida Peninsula was separated from the mainland United States by a negative area called the Suwannee Straits. To the south of this feature existed an environment similar to today?s Bahamo Banks where very pure calcium and magnesium carbonates with associated evaporites were deposited. Thus the Eocene and Oligocene contain little or no quartz sand or clay minerals except in the Panhandle west of the Suwannee Straits where some clastics were contributed by rivers from the north.

Jan 1, 1966

By Eric Ohl

Due to the world&apos;s ever increasing minerals and energy demands, process plants have to cope economically with ever growing throughput rates. This trend has accelerated the development of high capacity vibrating screens. Screens with screening areas of 30 to 50 square meter (322 to 540 square feet) and width of 5.5 meter (18&apos;) are technically possible and are being used presently with great success. This paper will concern itself with the general aspects of large screen design, by using modern technology and the latest findings with regards to fatigue strengths relative to the laws of vibration. It also will investigate the technical and economical limits of such designs.

Jan 1, 1983

By William H. Dresher

The crust of the earth, together with its seas and its atmosphere, is the source of all of mankind&apos;s primary wealth. Indeed, most people think of precious metals and stones when they think of wealth mined from the earth, but the value of the material and energy goods derived from the earth far exceed the value of the precious metals and gem stones. Thus, it is obvious that all minerals which we mine from the ground represent new wealth--the copper, clay, or petroleum we mine just as much as the gold or silver. More and more, wealth is defined in terms of utility-not in terms of an arbitrarily established monetary value. The recent action of the OPEC nations in controlling the flow of petroleum has clearly demonstrated this to the petroleum-importing nations! There is developing in the United States, as well as in many other nations of the world, a concern for the future availability of many mineral-derived raw materials and of mineral fuels. Ore grades are diminishing, concern for the environment has placed restraints on commercial development of some mineral deposits and the processing facilities necessary to exploit them, and countries upon which we have relied for major mineral materials have become increasingly nationalistic, causing uncertainties in future supply and causing an increasingly alarming deficit in our nation&apos;s balance in trade.

Jan 1, 1980