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By Alexander Pomerantsev

In recent years, bucketwheel excavators have found wide application in open pit surface mining not only because of their large production capacities, but also because they easily lend themselves to automation. Krupp, Orenstein & Koppel, Buckau-Wolf, Mechanical Excavator, Lauchhammer, Manufacturers in Eastern Europe designed and installed many models of bucketwheel excavators that can excavate any type of materials, could be used in any climate conditions and for any type of technological schemes in open pit surface mining, (Photo I, II and III)

Jan 1, 1979

By James L. Coburn

Leaching is defined as a form of extraction in which a valuable constituent is removed from a solid body by mass transfer to a solution which, for the purpose of this discussion, is considered to be an aqueous medium. Historically, leaching has been applied to the recovery and purification of many elements. This paper, however, is directed toward the recovery of copper, uranium, vanadium, and precious metals included in the following systems: 1. The leaching of copper minerals, sulfides and oxides, by acid or by ammoniacal leach solutions with or without an oxidant. 2. The leaching of gold and silver, either native metals or as minerals by an oxygen-containing alkaline cyanide solution. 3. The solubilization of certain uranium and vanadium minerals by oxygen or oxidant-bearing lixiviants. Many other systems of this general type exist, but from a production standpoint, these three systems account for most of the major values recovered by leaching.

Jan 1, 1975

By M. C. Fuerstenau

Flotation data indicate that sulfonate and dodecylamine adsorb physically on Mn02 at ambient temperature. Oleate also adsorbs physically if the zero-point-of-charge of the Mn02 is sufficiently high. Chemisorption of oleate apparently occurs between pH 8 and 9, and this phenomenon is enhanced considerably at elevated temperature.

Jan 1, 1966

By R. V. Ramani

In 1970, of the 603 million tons of coal produced in the United States, 339 million tons, or 56%, were produced by under- ground mines. While the ratio of underground to surface production has been decreasing in the last few years, it is anticipated that a 60:40 ratio of underground to surface-mined coal will remain for some time. Underground coal operators are continuing to invest in new mines and are interested in increasing the efficiency of all their operations. One area for improvement is in mine planning and design, particularly in the area of selection of equipment for operation. Because of the availability of a wide variety of equipment, a fair degree of selectivity can be exercised in the choice of equipment for a particular job. However, such a choice must be made on the basis of technological facts and forecasts related to the mining operation. If the mining conditions can be reasonably predicted, along with a mining plan, it should be possible to insure the selection of the right equipment for the particular application. In order to increase the efficiency of underground coal operations, it is necessary to understand not only the operating system in detail, but the inter-relationships between system components and the operating environment. With such an understanding comes the application of simulation and other operations research techniques to plan and operate mining systems. Computer simulation studies have been successfully adapted to underground coal mining, and applications by Prelaz et al. (1965), and Manula and Sanford (1969) are some that are being used by the mining companies. However, a need still exists for better understanding of certain intra-system and system-environment interactions in order that computer simulation programs may be provided with better input data for more effective application. This paper deals with one aspect of the coal-winning system in need of better definition, namely, studying the performance of continuous miners.

Jan 1, 1973

By J. Réal Cloutier

[Options are a natural extension of the forward and futures markets as they offer fexible method of hedging exposure. -An organized options market is preferable to the "over the counter forward markets since EGCC (EOE, ME, VSE) assumes responsibility for contract fulfillment minimizing credit risks by guaranteeing transactions. -Options ante considerably more "fexible" than the futures and forward markets, permitting prompt, precise and respected adjustment of one's exposure risk position. -The risk to the buyer of the options market is limited to the initial premium paid.]

Jan 1, 1983

By Adrian E. Scheidegger

Recently, a new theory of the subsidence of rock masses has been advanced by Litwiniszyn and coworkers, which is based on the notion that the individual rock particles perform random walks. It is shown in the present paper that the final equations of the random walk theory can be justified from general principles of statistical mechanics in which no specific theoretical model of particle behavior has to be made. The theory appears to account appropriately for subsidence phenomena.

Jan 1, 1966

By G. Almgren

With the exception of sublevel caving, the most common method of underground mining in Sweden is the "cut-and-fill" method. It is normally used for mining non-ferrous metals , and' is used extensively in the complex sulfide ore mines of the Boliden Company in north and central Sweden as well as the mines of the STORA and Vieille Montagne Companies in central Sweden. All in all, the cut-and-fill method is used in 13 of Sweden's 45 mines. As the mines are relatively small, the volume of ore mined by this method represents only about 5 % of the total ore production in Sweden. The commercial value, however, is much large than this percentage would imply. The production volumes and grades of some typical mines are shown in Table I. As seen, when rated internationally, the grades are comparatively low. The prices are set according to ?international metal prices? as dictated by the London stock exchange, and in lieu of governmental support, rational management methods are critical in order to achieve satisfactory profit.

Jan 1, 1975

By James R. Yancik

Economical and environmental pressures necessitates the recovery of the minus 0.6 mm x 0 coal generated by todays mining machines. This size fraction, dependent on the type of production unit, maintenance of the production unit, and the Hardgrove Grindability Index, can be a substantial portion of the Preparation Plant feed. Historically, dewatering of the collected 0.6 mm x 0 product has often been rather expensive and marginal with respect to surface moisture reduction. The Freeman United Crown II Preparation Plant more than adequately demonstrates that the continuous scroll type centrifuge can dewater 0.6 mm x 0 coal to acceptable surface moisture levels.

Jan 1, 1981

By Ande&apos, Bengt n

The first Model 480 SALA-HGMS R carousel high gradient magnetic separator was recently manufactured (Figure 1). The carousel's design was based upon the high gradient magnetic separation technology developed and owned by Sala Magnetics Incorporated, Cambridge, Massachusetts. After a short (approximately 300 hours) in-house mechanical and electrical test and break-in period, the carousel was ready for a long term demonstration test. This paper describes the demonstration plant and operational performance of the Model 480 HGMS treating a low grade iron ore tailings. A location convenient to Sala International's main office in Sala, Sweden was desirable because Sala engineers and technicians were to operate the demonstration plant. The Strassa iron ore mine in central Sweden was chosen because it fit most of the criteria that was important for a good demonstration site. The Strassa mine is part of the state owned Svenskt Stal AB. The mine produces about 320,000 tons of iron concentrate per year consisting of 200,000 tons of magnitite concentrate and 120,000 tons of hematite concentrate.

Jan 1, 1980

By Allan Gebhard

The purpose of this paper is to summarize the role of water resource monitoring in mining activities and to discuss the considerations that go into designing and implementing a monitoring program. The design of a monitoring program is invariably based on sound engineering and scientific judgement since no design formulas exist that can be universlly applied to the monitoring of all activities. As discussed in this paper, however, a methodology of designing a water resource monitoring program does exist. In order to cost-effectively monitor the water resource impacts of mining activities, the following three monitoring related items should be understood: 1. the role of water resource monitoring in the planning, construction, and operational stages of mine development, 2. the available water resources monitoring methods and the proper role of each method in the various scages of mine development, and 3. the strategies that should be followed in designing and implementing a water resource monitoring program.

Jan 1, 1976

By D. S. Choi

Underground production of coal by longwall methods has increased significantly in the last few years and will very likely continue to: increase. There are several reasons for this. First, as mining moves into seams having greater overburden, roof exposure must be reduced since support will become' increasingly expensive. Secondly, the growing demand for coal has forced the coal industry to seek alternative, more productive, coal mining methods. In addition, the longwall method greatly simplifies the underground ventilation network. This paper addresses itself to the design of longwall development headings, particularly to those of the United States where multiple development headings are required by law. The most burdensome problem encountered in many longwall mining installations is deterioration of the tailgate due to the combined effect from, the active longwall gob and the old gob made by mining the previous panel.1 Portions of the tailgate entry are sometimes closed to such a degree that extensive repair work is necessary to keep the entry in usable condition. The purpose of this paper is to present the result of a study in progress which combines field measurements with numerical model analysis to reduce the cost of maintaining tailgate entries in longwall mining systems.

Jan 1, 1975

By R. E. Driscoll

The exploration, geologist of necessity has to have a wide working knowledge of many specialties other than hiw own, First he has to use his own technical background to find a deposit,, of a mineral that is of interest, Once found, his problems are Just beginning, He then has to assume the role of an economist, an accountant, a mining engineer, a chemist, a metallurgist,, a salesman and what-have you, In the economic field, he must determine the marketability of either the ore or the refined mineral. He must gauge the supply and demand for the particular mineral he is interested in and make his best guess as to ultimate cash flow from a deposit over the estimated life of said deposit, He must then assume the role of a mining man and estimate cost of recovery, including an, evaluation of the most economic mining method, cost of supplies and labor, and again estimate a net cash flow. He must then determine amenability of ore to economic metallurgical methods, he must determine the legal status of the property involved and, after analysis of the specific situation, determine the best approach to a deal, After all of this he must sell it to the people who will put up the money and then put his deal together and sell it to the people who own the minerals, if that be necessary. Then he has to sit back, with crossed fingers and crossed legs wondering for some months, and in many cases even years, whether or not he is right. The expenditures required to open up a mine in this day of wild inflation are such that he has to be right, and the responsibilities are awesome.

Jan 1, 1958

By G. P. Richards

RIP is the process of recovering uranium from an unclarified slime pulp which comes in contact with a moving bed of ion exchange resin, T e sand-slime separation of the acid-leach slurry is accomplished through the use of cyclones and spiral, akins type classifiers. Course sands are discarded to tailings and the combined slimes and leach liquor become the IX feed. Uranium in the IX feed is absorbed on the resin and after exhaustion the barren pulp is directed to tails, Following the uranium exhaustion cycle an eluant solution passes through the resin bed stripping the uranium from the beads, The uranium is precipitated from the clarified pregnant eluant, filtered, dried and packaged for shipment to the AEC, Normally, the ore received at the Mines Development plant is a loosely cemented sandstone containing small quantities of clay and bentonite, The ore is easily crushed and requires only a 1/3 load of rods in the rod mill to reduce the ore to grain size, Very little of the ore is recirculated by the 42" spiral classifier.

Jan 1, 1958

By D. A. Shock

Utilizing the technology developed for oil well stimulation by hydrofracing, a disposal system which permanently fixes the waste has been proven. Large quantities of radioactive waste can be processed by a single well system making this method an attractive method for permanent radioactive waste disposal. The system depends on locating a relatively thick formation of impermeable, but easily fracturable rock such as a shale, creating a horizontal fracture, pumping the waste into the fracture in a form which will subsequently solidify and seal the fracture from the well system. The paper presents the theoretical considerations from creating and extending horizontal fractures and how these considerations were used in designing a waste disposal system which is now operating.

Jan 1, 1964

By N. L. Parduhn

Populations of Bacillus cereus spores are elevated in soils over four subsurface gold deposits in the western United States. Large deposit-to-background ratios of B. cereus populations were obtained in soil traverses over the Minnesota vein deposit, Empire District, Colorado (maximum 50:1); the Shasta (maximum 3,500:1), and Evening Star maximum 18,000:1) vein deposits, Shasta County, California; and the Hog Ranch disseminated gold deposit (maximum 40,000:1) in Washoe County, Nevada. Small increases in the concentration of toxic metals in the soil may be responsible for the elevated spore populations. The observed elevation of B. cereus spore populations near these gold deposits indicates that the method should be further investigated as a potential exploration tool.

Jan 1, 2013

By David C. Grant

During in situ uranium mining using ammonium bicarbonate lixiviant, the ammonium exchanges with cations on the ore's clay. Mter mining is complete, the ammonium may desorb into post-leach ground water. For the particular ore studied, other chemicals (i.e., uranium and selenium) which are mobilized during the leach process, have also been found in the post-leach ground water. Laboratory column tests, used to simulate the leaching process, have shown that aluminum chloride can rapidly remove ammonium from the ore and thus greatly reduce the subsequent ammonium leakage level into ground water. The aluminum chloride has also been found to reduce the leakage levels of uranium and selenium. In addition, the aluminum chloride treatment produces a rapid improvement in permeability.

Jan 1, 1982

By Alexander Sutulov

It is calculated that since the beginning of last century, which practically coincides with the beginning of the Industrial Revolution, our civilization has consumed around 239.5 million tons of copper (see: Table 1). According to the most pessimistic projections of today, with only a 2.5% annual growth rate in demand, we are bound until the end of this century to consume another 200 million tons of copper in remaining 17 years. A recent study made by US Bureau of Mines (1) indicates that the proven ore reserves of 150 major operating mines and about 120 deposits sufficiently explored for development and feasibility studies accumulate a total mass of 49.3 billion tons of ore, assaying an average of 0.82% Cu and containing around 324 million tons of recoverable copper. Consequently, there is a high grade of probability that the bulk of our future ore supplies, for our demand of, say, next 25 years will cane precisely from these mines. The interesting point in USBM study is that it indicates the recoverable byproduct content of these ores and which is: 118.2 million troy ounces of gold 2277.4 million troy ounces of silver 7.1 million tons of lead 24.7 million tons of zinc 1.3 million tons of nickel 3.1 million tons of molybdenum 765 thousand tons of cobalt, and 720 thousand troy ounces of platinum. This information gives us a relatively reliable profile of our future ores for next 25 years, and thus makes possible evaluation of byproduct credits in our future copper mining and producing activities.

Jan 1, 1983

By Douglas M. Deason

Swelling clays, such as montmorillonite, contribute significantly to the poor dewatering and consolidation behavior of the Florida phosphate clay wastes. Understanding and to a degree, control of the forces which cause the swelling behavior may aid in supplying a solution to this problem. The technical feasibility of utilizing control- led dispersion for aiding dewatering of phosphatic slimes was investigated. This technique is based upon inhibition of swelling and self-dispersing tendencies of the montmorillonite clays by dispersing the solids in electrolyte solutions. Through this process, significant improvements in settling rates and sediment solids content were achieved in both pure clay systems and on simulated phosphate slimes.

Jan 1, 1983

By W. E. Sabina

In the short period of one mans? career we have seen specifications for bulk material handling systems and equipment grow from two or three pages to as much as two or three volumes for a single contract. The old 'short form' described what the purchaser expected the equipment to do. The long form does the same but also includes nut, bolt, and lockwasher depth of detail. What are the events that led to this proliferation of verbiage, and does it benefit the buyer in the final analysis? Is there a better way to purchase complex equipment while ensuring the highest quality for the dollar spent?

Jan 1, 1986

By Brij M. Moudgil

Separation of oil shale from waste material or into high grade and low grade fractions can have a major influence on the economics of the surface (ex-situ) retorting process. Different components of shale rock vary significantly in physical and surface chemical properties such as specific gravity, color, water wettability etc. Various techniques which utilize the difference in one or more of the above propartis have been proposed to preconcentrate the oil shale before retorting. A discussion of the techniques proposed such as gravity separation, sorting and froth flotation is presented.

Jan 1, 1982