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By D. W. Tedder

Several bauxite feeds and residue sands and muds, produced by Bayer plants in the US and over-seas, were fractionated using dry and wet magnetic separators. The magnetic sand fractions typically contained about 50 to 60 wt % Fe2O3 and the bulk of the radioactivity in the sands. The muds are more difficult to process, but some fractionation is possible using a combination of classification and magnetic separation techniques. Among the mud samples, higher radiation levels are often associated with the less magnetic fractions. Bauxite is more easily fractionated using dry magnetic separation. Much of the radioactivity in bauxite appears to concentrate in the sand and mud residuals.

Jan 1, 1987

By James A. Erdman

This overview briefly describes some examples of applications and difficulties in using plants that are drawn from the literature and from field experience. Because of the generally low Au concentra¬tions found in plants, the analysis of plant tissue is critical to the successful application of the biogeochemical method of prospecting. Neutron activation analysis is the most widely used method to detect Au in plants, due largely to its sensitivity; levels in the parts per billion range are easily attained. Two general types of sampling media are used in prospecting for Au: humus and living plants. Humus has been widely used in Canada, but the sampling of plants has increased there and elsewhere in recent years. The use of douglas-fir (Paeudotsuga menziesii) at a Au-bearing stockwork in Idaho is a prime example. A maximum Au concentration of 14 ppm was detected in the wood ash of this coniferous tree, well above the normal background concentration of about 0.15 ppm. Among shrubs that might be useful in Au prospecting, sagebrush or wormwood (genus Artemisia) could be sampled because it is extremely responsive to concealed mineralization. It has been used extensively in the Soviet Union and could be used in areas of the western United States where disseminated Au occurrences might be located. Among the problems one may encounter in using plants for Au prospecting are (1) physiological barriers, by which many plant species simply do not absorb Au at detectable levels; (2) misconceptions of soil-plant correlations; (3) localization of Au in plant tissue; and (4) the variation of Au concentrations due to season. Despite these limitations, biogeochemical techniques can complement or replace other geochemical methods currently used.

Jan 1, 2013

By Ing. H. Kellerwessel, Ing. M. Esna-Ashari

This paper refers to the new crushing and grinding process, invented by Professor Schonert (Ref. 1), Clausthal, Germany. The process is known as high pressure particle bed comminution or interparticle crushing. Several papers already describe fundamentals of the process, the equipment used, results of lab size and large scale tests and the first results of commercial operations (Ref. 2 to 7). Of course, we will treat the topic from the perspective of a downstream gold ore upgrading or leaching process. Some recently executed testwork indicates that the process provides special advantages in this field. To describe the process generally, in view of the already existing publications.

Jan 1, 1998

By J. B. Hiskey, V. P. Atluri

Resin-in-leach (RIL) cyanidation experiments were performed on a refractory carbonaceous gold ore. The objective of this investigation was to determine if strong-base ion exchange resins could adsorb the soluble aurocyanide complex in preference to natural "preg robbing" organic constituents. Direct cyanidation of the carbonaceous gold ore used in this study resulted in less than 2% gold extraction in 24 hr. RIL cyanidation resulted in about 70% gold recovery onto the resin. Kinetic experiments indicated that 50% of the gold is extracted after 1 hr of leaching. Resin breakage was investigated for as-received and preattrited resins. Similar results were obtained with three different strong base resins.

Jan 1, 1990

By Shulin Xu, Moreno Pescara, Nicola Avagnina, Piergiorgio Grasso

The Roreto Tunnel is a shallow, twin-bore, road tunnel on the connection between the A6 and the A21 motorway in NW Italy. The challenges faced the design and construction of this tunnel derive from 1) the presence of groundwater, both phreatic and artesian; 2) excavation in loose and/or little cohesive materials; 3) excavation in cohesive materials containing water-saturated, sand lenses; and 4) surface constraints due to the urban environment. In this paper, these problems are examined and the rationale led to the optimum design choices and construction solutions explained. The experience should be useful to others when tunneling in similar situations.

Jan 1, 2003

The primary goal of a maintenance information system should be to aid the maintenance department in providing the required equipment or plant availability at the lowest possible cost. To achieve this goal, the system must provide information in support of the following objectives: (1) establishing the best fleet, equipment, and component configuration; (2) establishing the best maintenance program; (3) executing the defined maintenance program efficiently; and (4) monitoring equipment availability. These objectives can be satisfied with five groups of reports. Each of these groups should provide regular, periodic reports to aid in planning and monitoring trends, exception reports to identify problems, and on-request reports to provide analytical capabilities.

Jan 1, 1979

By Fathi Habashi

LEACHING IS the process of extracting a soluble constituent from a solid by means of a solvent. In extractive metallurgy it is the process of dissolving a certain mineral (or minerals) from an ore or a concentrate, or dissolving certain constituents from metallurgical products such as calcines, mattes, scrap alloys, anodic slimes, etc. In this respect, either one of two purposes can be achieved: 1) Opening of ores, concentrates, or metallurgical products to recover the metal values. 2) Leaching easily soluble constituents (usually gangue minerals) in an ore or a concentrate in order to have it in a more concentrated form, e.g., the

Jan 1, 1970

By Wilfred M. Kenan

The relationship of various genetic classifications of graphite, their properties and general applications are reviewed. The classifications being amorphous, flake, high crystalline (vein) primary synthetic graphite and secondary graphite. The properties discussed are size, carbon, sulfur, ash content, general chemical analysis and degree of graphitization of each type. The major sources for natural and synthetic graphite powders are discussed in addition to factors which govern the cost as well as the supply. The economics of graphite are basically determined by the consumer and the end application. Graphite is a strategic mineral and is on the government stockpile list.

Jan 1, 1984

By Douglas A. Sloan

Who would believe that young elementary school children could understand something as complex as the mining industry? THE CHALLENGE The challenge of accomplishing this is tremendous. An examination of Canadian school children indicated that they knew very little about the world of work in general, and hardly anything about the mineral resource industry in particular. It calls to mind the story about two youngsters who decided to play house. The little girl played her role well as she went about the house doing things she had watched her mother do every day. When it was the little boy's turn, he grabbed his lunch, waved goodbye to his "wife", jumped on his bicycle and pedalled furiously down to the end of the driveway -- where he stopped. The youngster explained that he saw his dad go out of the driveway each morning, but he didn't know where he went, or what he did on the job. When you stop to consider the number of families today with two working parents, you can begin to appreciate the importance of the opportunities for role identity provided by this project.

Jan 1, 1979

By C. G. Janes, N. Finkelstein, L. M. Jr. Johnson

In May, 1966, the General Services Administration (GSA) announced a program to encourage additional domestic production of copper in the interest of national security. Upon learning of the copper production expansion program, Duval Corporation entered into negotiations with GSA for development of the Sierrita copper-molybdenum property under the program. Agreements between the GSA and Duval Sierrita Corporation, a wholly owned subsidiary of Duval Corporation, were concluded in 1967, with the Sierrita Concentrator beginning operation in 1970 at a designed capacity of 72,000 STPD. Subsequent additions and modifications have expanded capacity to 90,000 STPD. This property, located approximately 20 miles south of Tucson, Arizona, represents an investment including working capital of about $200 million. These funds were provided from an $83 million loan from GSA, repayable in copper valued at 38 cents per pound, $48.75 million of bank loans subject to U. S. Government V- loan guarantees, and Company capital contributions. Current general operating statistics for the concentrator are listed below: Ore Grade 0.32% Cu., 0.030% Mo. Daily Tons Milled 90,000 STPD Annual Copper Production 94,600 Tons Annual Molybdenum Production 15,000,000 Lbs. Annual Silver Production 1,135,000 Ounces

Jan 1, 1976

By Robert H. Poppe

The Regional Copper-Nickel Study examined the potential impacts of copper-nickel sulfide mining, concentrating and smelting operations in northeastern Minnesota and gathered extensive monitoring data on the ecological characteristics of the region's aquatic and terrestrial biota. Because of the many development options possible, the diversity of the region's ecology, and the uncertainty of future environmental regulatory requirements, the Study did not attempt to measure the magnitude of environmental impacts on specific biological communities from a specific development proposal. The Study provides a broad base of environmental resource and impact information that hopefully will assist mining developers and environmental regulators when assessing specific proposals in the future. The following discussion is not a description of what will happen if copper-nickel development occurs in northeastern Minnesota but an exploration of why certain potential aspects of such development should be carefully considered and adequately understood before unnecessary or irreversible decisions are made.

Jan 1, 1980

By D. N. Madge

A survey is given of production scheduling systems currently in use or contemplated for future use in Cominco operations. Emphasis in this presentation is made on the chain of decisions that are made with the help of mathematical programming models. Some attention is devoted to the structural properties of the models.

Jan 1, 1966

By Jerry W. Danni, R. Craig Ford, Kermit C. Benke, Jim B. Finley, Donald D. Runnells

Steady-state water balance models have historically been used in the management of acid drainage at mine sites. Such systems could be more realistically described by non-steady-state conditions. In addition, the evaluation of alternatives for closure and management of acid drainage must consider non-steady-state conditions. Dynamic systems modeling is a method for simulating water management systems, offering flexibility in: (1) simulating either steady-state or non-steady-state conditions, (2) allowing "what-if' scenario testing. and (3) optimization of operation and closure alternatives. A case study is given for acidic drainage management during closure at a heap leach facility that demonstrates the utility of dynamic systems models.

Jan 1, 2000

By Harold A. Taylor

The first use of graphite is lost in the mists of time. It was used by primitive man to make drawings on the walls of caves and by the Egyptians to decorate pottery. As early as 1400 AD graphite crucibles were being made in the Haffnerzell District of Bavaria. Through the Middle Ages graphite was confused with other minerals, especially galena and molybdenite. Two common names that are still being used for the mineral are plumbago, meaning lead-silver, and black lead. The latter name implied that graphite is either composed of lead or at least contains a large percentage of it. Gessner is credited with having recognized it as a separate mineral in 1565, but its composition was not determined until 1779, when Scheele demonstrated that graphite oxidized to carbon dioxide, thus proving its carbon constitution. In 1789, Werner named it graphite from the Greek word graphein, meaning to write. The United States has long relied on foreign countries for its graphite supplies. This reliance has been due more to the lack of suitable domestic graphites than to any particular preference for buying minerals overseas. Sri Lankan graphites were imported as early as 1820, and Madagascar graphites have been imported since the properties on that island were opened up about a hundred years later. Mexico has long supplied the United States with most of its requirements for amorphous graphite.

Jan 1, 1994

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 J. J. Gusek, T. C. Richmond, R. W. Reisinger

A high-altitude (9,500-ft [2,900-m]) historic underground copper mine in Wyoming discharges neutral but copper-laden water into a pristine creek. Under a Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) deferral agreement, the Wyoming Abandoned Mine Land Program performed site characterization and treatment studies in preparation for reclamation of the site. An integral part of the project included addressing the needs of a variety of interested and affected parties, including property owners, local populations, government agencies, and the media. This paper discusses an overall approach and specific methods employed to enlist public support for the project as well as some of the successes and failures experienced.

Jan 1, 2004

By S. Acar, P. Somasundaran

Results of selective flocculation of natural ores containing two or more minerals and of synthetic mineral mixtures do not usually agree with what is expected on the basis of the results from single mineral tests (Acar and Somasundaran, 1985). This is mainly due to the ionic species released by the minerals, which act differently under different pH values. The objective of this investigation was to study 1) the surface chemical composition of selected sulfide minerals-natural chalcopyrite and pentlandite and synthetic covellite, millerite, and pyrrhotite-and 2) the changes brought about by the dissolved mineral species. Electron Spectroscopy for Chemical Analysis (ESCA) was used to perform the surface analyses.

Jan 1, 1991

MULSIM/NL and La Model are displacement-discontinuity programs which have been used quite successfully in the past to provide detailed structural models of various single and multiple-seam mining situations. However, both of these programs required fairly complex details of the mine plan and topography to be manually input into the program, often taking several days of work. Recently, automatic mine and topographic grid generation capabilities have been added to the MULSIM/NL and La Model programs, reducing the input time requirements from days to hours. This paper discusses the algorithms used for the automatic grid generation and demonstrates the utility of the new capabilities with a case study.

Jan 1, 2003

By G. A. Hope, K. Watling, R. Woods, I. Chandra, I. M. Ritchie

This paper presents two aspects of gold leaching research and development. The first section of the paper covers the development of innovative gold leaching processes. The research in this area has concentrated on the development of new thiosulfate leaching systems which use Fe(III) stabilized by ligands as the oxidant in place of copper(II)+ammonia. The second section will cover the development of innovative techniques such as surface enhanced Raman scattering (SERS) to study the leaching of gold in cyanide solutions. It will be shown that the use of in-situ SERS yields information which cannot be obtained using other methodologies.

Jan 1, 2005

By James J. Scott

To the safety engineer, mine planning engineer, and mine inspector associated with an underground operation, stability of the underground structure is of the utmost importance. In the United States in 1961 rock falls killed 167 miners, crippled many more, and cost the industry a fortune in lost equipment and production. Much research has been carried on to try to find ways to eliminate this loss of life and property. Within the past few years the interest in rock mechanics as a science has been at its highest point, Private industry, government agencies, universities and foundations have launched studies to gain a better basic understanding of the stability of underground openings.

Jan 1, 1966