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By F. S. Knoll

The high tension process which separates materials based on relative differences in surface conductivity has been very successful in recovering non-ferrous metals from municipal waste. Aluminum is by far the largest constitutent of the total non-ferrous metal fraction; accounting for >95% in most localities. Wire and insulation mixtures from industrial wastes have been treated commercially for several years by a high tension process initially developed for use in the iron ore industry. The wire and insulation application was a forerunner of municipal waste dry treatment technology. In the past eighteen months the rotating-drum-type electrostatic separator has undergone extensive testing and development in order that the process might be efficiently adapted to the recovery of aluminum from municipal waste.

Jan 1, 1974

By C. E. Silverblatt

The advent of larger quantities of -1/4 inch coal in the raw feed to the preparation plant and the necessity of recovering this material has made the problem of meeting product moisture specifications more difficult. For a number of years thermal dryers have been used advantageously as a means of reducing fine coal moisture content where the over-all economics would justify such an installation. However, these units are not without their drawbacks because of high capital and operating costs, safety hazards and possible degradation of the product, and thus an alternative method of moisture reduction is highly desirable. After the various mechanical variables associated with filtration have been optimized, an examination of theory shows that surface tension and liquid viscosity are the only two remaining variables which might be altered to reduce moisture content.

Jan 1, 1964

By O. J. Malacarne

The use of a series of thickeners for-washing of the slime fraction of a leached ore is not uncommon in the uranium industry; however, few ore processing mills have used a thickener circuit for washing leached total ore. The, common, practice is to wash the sand fraction in classifiers and, the slime fraction only in thickeners. At the Uravan mill of Union Carbide Nuclear, Company, a total ore' acid leach is employed to extract uranium values from sandstone ores. These leached ores are then washed at a nominal rate of from 1,000 to 1,300 tons per day in a series of washing thickeners. A typical screen. analysis of the ore being washed in these thickeners, is 25 percent -200 mesh, 3 percent +35 mesh and about, one' percent +l4 mesh., The amount of slimes (-200 mesh) will vary from 20 to 30 percent s the mill receives ore from 150 different mines The washing liquor is acidic, from a pH of about 2 in the first thickener to 0.6 pH in the last thickener and of course ally acid duty equipment must be used. The Uravan mill of Union Carbide Nuclear Company is located in Montrose County, Colorado and is physically located on a canyon wall along the San Miguel river. The thickeners referred to in this, paper are located on top of the mesa above the canyon. For purposes of identification, these thickeners are numbered 1 through 8 from south to north.

Jan 1, 1962

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

By M. F. Martin

Dewatering aids are chemicals which enhance the efficiency of mechanical dewatering equipment such as vacuum disc filters and centrifugal dryers. A new dewatering aid has been developed which significantly lowers the moisture content of the mineral concentrate and causes none of the undesirable side effects normally associated with dewatering aids. Highlights of product development from laboratory screening through field testing will be discussed.

Jan 1, 1985

By Richard B. Stein

This paper will present an overview of several hydrometallurgical processes which can be used for sea-nodule metal recovery and some simplified economics. Before going any further, here are some of the basic figures from which the economics were developed. The first is to establish a representative composition for a typical nodule feed (Slide 1). This set of chemical analysis figures can be taken as typical for a deep Pacific nodule feed and shows manganese at 30%, copper at 1.1%, cobalt at 0.2%, nickel at 13% and iron at 10% for the metals of economic interest1.

Jan 1, 1982

By A. J. Naldrett

Over the past six or seven years important new ideas have been developed concerning the origin of nickel sulfide deposits. To a large extent these have been stimulated by the major nickel discoveries of the Eastern Goldfields area of Western Australia (Woodall and Travis, 1969; Ewers and Hudson, 1972). Prior to these finds, the most important nickel camps were regarded as being associated exclusively with intrusive rocks such as the Nickel Irruptive at Sudbury or the intrusive peridotites at Thompson, rocks that were thought to have no close association with volcanism. Study of the Australian discoveries, coupled with work in South Africa (Viljoen and Viljoen, 1969) and Canada (Naldrett and Mason, 1968; Pyke, Naldrett and Eckstrand, 1973), has shown that volcanic rocks with true ultramafic compositions and extrusion temperatures of 1400 to 1600°C were a common feature during the Archean. Under certain circumstances economic concentrations of nickel sulfides have formed from these rocks, either settling to the base of their associated flows or accumulating in shallow intrusive feeders to the flows. The aim of this article is to show how these ultramafic rocks can be recognized, how the nickel deposits, if present, are likely to occur within them, and what special features characterize ore-bearing examples of the rocks.

Jan 1, 1975

By A. M. Johnson, M. A. Cornachione

The west central Upper Peninsula of Michigan contains a large resource of graphitic slate. The slate has potential industrial use as a substitute for shale currently used in the production of portland cement. Some of the unweathered slate, however, has a high concentration of pyritic sulfur that can create emission problems when processed in a kiln. A low-cost method to reduce the sulfur content of the slate through the optimization of pyrite oxidation in a bio-heap leaching operation was investigated. In this study, optimal conditions for the bacterium Thiobacillus ferrooxidans were created to promote pyrite oxidation and, therefore, sulfur removal from the slate. Preliminary lab scale flask tests using crushed and sized slate (-40 + 100 mesh) and T. ferrooxidans bacteria in a sulfuric acid medium resulted in 70% oxidation of pyrite over a one-month period. Subsequent column leaching tests on coarser materials (-3/8+1/4 in.) operated for six months resulted in a maximum reduction of total sum of 75%. These data suggest that bio-heap leaching to remove sulfur from the slate for use as a kiln feed material is viable.

Jan 1, 1995

By Paul Dean Proctor

The world's population by 2000 A. D. may approximate 6.5 billion and the United States' 304 million. South Asian population increases between 1970 and 2000 A. D. will be triple the projected population of North America. Such anticipated dramatic and probably traumatic increases in world population yield grave concern for the standard of living in the world and the United States. The people of the United States currently consume 32 percent of the world's energy and similarly large percentages of the world's mineral raw materials. With only 6 percent of the present world's population and slightly smaller percentage by 2000 A. D., much expanded world-wide production of energy and raw materials will be required to maintain even a standstill living standard. A minimal 2 percent increase per year in the standard of living in the United States and a 4 percent increase elsewhere in the world, beyond the demands of the estimated population increases, suggest the magnitude of the increased need for energy-mineral raw materials and the possible crises the world will face in these areas by 2000 A. D. Mineral engineers and scientists with broad educational backgrounds will be required in greatly increased numbers to help alleviate, and possibly avert, expected energy-mineral raw materials shortages of the next millenium. Explorationists, mineral engineers, commodity economists, environmentalists, city, county, state, and federal mineral materials planners and coordinators, and metallurgists will be among those most needed. AIME membership in the second century of the Institute's history will contribute directly to this personnel pool.

Jan 1, 1971

By C. R. Montgomery

Coal companies in order to supply their customers En the metallurgical market, both home and abroad, must be able to control their production in order to meet carbonization specifications over and above those of the proximate analyses which has been the prime consideration of purchases in the past. It is the purpose of this paper to review in brief some of the tests used and give data to show the application of such as it applies to the customers needs. It is now recognized that coal is not homogeneous in any of its properties and an amazing fact is that it has been used for so long a time as the principal raw material for the manufacturing of coke without more emphasis having been placed on the variation between coals; yes, even from coals in the same seam at different geographical locations, Recently Kuchta and Clendenin pointed this fact out In a study of the(1) carbonizing behavior as related to chemical and plastic properties of Alabama medium volatile coal.

Jan 1, 1962

By J. C. Motz

During the past five years, Rexnord has developed, tested and introduced the Nordberg Omnicone Crusher to the industry. When the Symons brothers invented the cone crusher over 60 years ago, they employed the principle wherein the length of the crushing stroke was related to the free fall of material by gravity. This permitted the material being crushed to fall vertically in the crushing chamber; and in effect, caused the particles to be crushed in a series of steps or stages as the particles got smaller due to the crushing action. This also helps to reduce the rate of wear of the liners since the sliding motion of the particles is minimized.

Jan 1, 1986

By J. M. Mercier

Approximately seven (7) years of recent intensive mining activity in the Wasatch Plateau Coal Field of Utah has revealed distinct geologic patterns which, at times, profoundly influence reserve estimates, coal quality, mine layout, and reserve accessibility. Mine planning, economic feasibility, and resource recovery activities by Getty Coal Company utilize a multi-faceted approach by necessity when evaluating Utah properties. Two specific operating mines offer examples of the affects of adverse geologic conditions on mine operation and project economics.

Jan 1, 1984

By John C. Morrisey, Harold M. Ray

With full production from the Casteel Mine in 1987 The Doe Run Company, a wholly owned subsidiary of the Fluor Corporation, encountered a significant increase of copper and iron to the Viburnum Mill. This major change of the lead, zinc, and copper metal ratios in the ore created circuit problems which adversely affected concentrate quality. Recognizing the problem, the company embarked on a metallurgical research program to include laboratory, pilot plant, and plant testing. The program developed an innovative copper prefloat process which both increased copper recovery and significantly improved concentrate quality. The process was tested and first operated at Doe Run's Brushy Creek Mill then installed at the Viburnum Mill in 1992. A brief history of development, plant operating data, and other potential applications for the patented processes will be described in the paper.

Jan 1, 1993

By Lucien Duckstein

The purpose of this paper is to give recommendations for utilization of water resources in a mining region, considering also water supply and environment; the case study of mining for coal and bauxite under the karstic aquifer of the Transdanubian mountain of Hungary is used to illustrate the approach, which consists in formulating a static multiobjective control model and solving it by compromise programming. The three activities of regional mineral resource exploitation, water supply and environmental protection are represented by different objectives which cannot be expressed in commensuerable units. Thus, a solution which is optimal for one objective is usually far from being optimal with respect to the other two objectives. As a result, we are not seeking an optimal solution for the conjunctive regional system, but a good compromise, trade-off or "satisfactum" (1), (2).

Jan 1, 1979

By C. I. Basilio

The adsorption of dialkyl di-and mono-thio-phosphinates on gold, silver and gold-silver alloys has been studied in the present work. These reagents, which are selective collectors for sulfide flotation, have been found to improve precious metals recovery from ores. Voltammetric studies have indicated that dithiophosphinate adsorbs on gold at much higher potentials than on silver, while monothiophosphinate adsorbs only on silver. However, both adsorb on gold-silver alloys with the adsorption potential decreasing with increasing silver content. Using FTIR spectroscopic measurements, the surface species formed during the interactions of these collectors have been identified. The results of the electrochemical and spectroscopic measurements have been compared with the contact angle data obtained at controlled potential conditions.

Jan 1, 1992

By W. A. McKinney

In conventional dump leaching of porphyry mine strip wastes, many years are required to extract up to 20 percent of the copper from the contained sulfide minerals. Furthermore, none of the molybdenum, gold, or silver in the strip wastes is recovered by current leaching practices. Because mineralization occurs predominately along fracture planes, breaking of the rock during mining operations liberates and concentrates some of the metal values in the fines. Research shows that upgraded fines can be screened from mine wastes and froth floated for early recovery of copper, molybdenum, gold, and silver. For example, screening a dump sample assaying 0.35 percent copper as chalcopyrite removed about 20 percent of the copper as minus 1/4-inch material that analyzed 0.6 percent copper. About 35 percent of the molybdenum and 20 percent of the gold and silver also reported in the fines. Crushing the mine dump sample to minus 3 inch before screening increased the distribution of copper and molybdenum in the minus 1/4-inch screen fraction to 28 and 50 percent, respectively. Similar results were obtained by screening fines from two other large samples of mine waste dump materials. Flotation studies established that the enriched minus 1/4-inch fines from the three dump samples could be effectively concentrated. Comparative testing revealed that the combination of froth flotation of fines and acid-ferric sulfate leaching of the coarser fraction enabled doubling the recovery of copper over direct leaching of the samples. In addition, significant amounts of molybdenum, gold, arid silver were recovered by flotation.

Jan 1, 1970

By Michael A. Werner

"A Yieldable Structure for Use in Areas of High Rock Stress & Deformation." Rock stress of up to 9000 psi have been recorded in the mines of the Coeur d'Alene Mining district. Associated with these large stresses are rock fractures and deformation. In order to maintain openings required for mining, large wood preparation structures are constructed to provide access to the work areas for men and materials. These wood raise preparation structures are costly to construct and maintain. Therefore a steel-foam concrete structure was designed and proposed for testing which would be less costly to construct, require no maintainence and maintain its structural integrity while allowing up to 53 inches of wall rock deformation.

Jan 1, 1984

By M. Misra

The dielectric properties and flotability of different ranks of Argonne Premium Coal samples are presented. The flotability of different ranks of coal are correlated with the dielectric properties and intrinsic moisture (or bound water) content. Measured dielectric properties of as-received coals and other constituents are incorporated into a mixture equation to calculate the dielectric properties of bound water present in the different ranks of coal. The nature of bound water present in low-rank hydrophilic coals is significantly different from that present in high-rank hydrophobic coals. The water molecules present in low-rank lignite have an oriented dipole-dipole interaction and are tightly bound to the surface. For high-rank coals, the water molecules are not bound to the surface and have a randomly distributed clathrate ice-like structure. Controlled thermal treatment can modify the structural nature of bound water present in low-rank hydrophilic coals and increase their flotability.

Jan 1, 1990

By K. T. Valsaraj, L. J. Thibodeaux

Solvent sublation, the separation process for the removal of two hydrophobic compounds (penta- and trichlorophenols) from the aqueous phase, is discussed, as is a steady-state mathematical model for fire process. Solvent Sublation "'as conducted in a continuous countercurrent mode. The underlying mechanisms, theory and experimental details on the effects of process variables on removal efficiency are reported.

Jan 1, 1994

By P. D. Chamberlin

Agglomeration for the heap leaching of gold and silver ores can be defined as the process of attaching fine ore particles (less than 100 mesh) to coarser particles so the fines are immobilized and uniformly distributed throughout the heap, thus making the heap more porous and uniformly permeable to the flow of a leaching solution. Agglomeration techniques and equipment to be described include drum and disc agglomerators, stockpile and belt agglomeration, and the use of vibrating deck and reverse running conveyors.

Jan 1, 1986