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By L. J. Dahl, S. E. Paulson, H. L. Kuhlman

To provide basic information on the processes occurring during in situ leaching, the US Bureau of Mines developed a geologic characterization research program. This includes laboratory experiments wing leaching apparatus that can accommodate whole core samples. Whole core experiments result in a higher proportion of ore mineral contact by the leach solution than packed column experiments. They also allow for the assessment of permeability changes taking place as the result of mineral dissolution, precipitation, and clay swelling within the flow channels of the rock. The leaching apparatus developed can be wed for either constant-pressure or constant- flow rate experiments and allows for the control of flow rate, pressure, and temperature during the experiments. Details of the experimental apparatus are presented, as well as preliminary results from the first series of experiments on an oxide copper ore from the Casa Grade, AZ area.

Jan 1, 1988

By D. T. Kinard, A. A. Schweizer

An operational 9 meter (30-foot) high gold heap leach pile was investigated by excavating test pits up to 6 meters (20 feet) deep, obtaining bulk and relatively undisturbed thin wall drive samples, and observing the ore distribution patterns exposed in the test pit walls. The clayey ore is crushed, agglomerated with lime and cement, and deposited on the leach pads using a radial stacker. Laboratory tests performed included moisture-density, gradation, compaction, Atterberg limits, permeability (constant and falling head), and triaxial strength tests. Discussion is presented on the effects of agglomeration on the permeability and strength characteristics of the in-place ore. Also discussed is the effect of deposition of the ore using the radial stacker.

Jan 1, 1987

By J. V. Calara, J. D. Miller

The sign of the surface potential for complex non-reactive ionic solids cannot be predicted solely from consideration of the hydration energy of gaseous ions which constitute the ionic lattice. Accurate analysis of these systems must involve the hydration energy of surface ions, which requires knowledge of the crystal structure, the identification of cleavage planes, and the calculation of binding energies of surface ions. Surface binding energies for ionic solids can be deter- mined if the Surface Madelung Constant is known. A computational technique was developed for the calculation of Madelung Constants for infinite lattices which gives excellent agreement with the values calculated by other more complicated methods reported in the literature. Extension of this technique permits the calculation of Surface Madelung Constants and binding energies of surface ions, ?Us, for semi-infinite solids. The hydration free energy of gaseous Ions, ?Fh, together with the calculated binding energy of surface ions, ?Us, allows calculation of the hydration energy of surface ions, ?Gh, as for the case of the ionic solid, MX:

Jan 1, 1976

By O. H. Tuovinen, T. M. Bhatti

Microbiological leaching has been used as an alternative approach to conventional hydrometallurgical methods of uranium extraction. In the microbiological leaching process, iron-oxidizing bacteria oxidize pyritic phases to ferric iron and sulfuric acid, and uranium is solubilized from the ore due to sulfuric acid attack. If uranium in the ore material is in the reduced, tetravalent form (UIV), a red ox reaction is involved whereby uranium is oxidized to the hexavalent form (UvI) upon dissolution. In acid-leaching systems, the primary oxidant is ferric iron, which is reduced to ferrous iron by its chemical reaction with UIV. The ferrous iron thus formed is reoxidized to ferric iron by iron-oxidizing bacteria such as Thiobacillus ferrooxidans and Leptospirillum ferrooxidans. Nutritional requirements and responses to environmental extremes of acidophilic iron-oxidizing bacteria are appraised. The S-entity in Fe-sulfides is oxidized to sulfate by bacteria similar to Thiobacillus ferrooxidans and Thiobacillus thiooxidans. Pyrite and marcasite oxidation is a sulfuric acid forming reaction. Heap, dump and in situ leach techniques are feasible as bacterial leaching systems.

Jan 1, 2000

By David A. Gulley

One of the advantages of the market¬place, economists believe, is that it automatically generates information which would otherwise be hard to come by. For example, supply and demand signals imply something about private and social sacrifices and benefits. This information is seldom perfect, and can neglect some costs and benefits, but it nevertheless is crucial data. Moreover, marketplaces can also eliminate the need for some information. For example; since market participants are voluntary actors, only those transactions are culminated in which a mutual gain occurs. This eliminates the need for some cost-benefit calculations. A corollary to this standard economic doctrine is that whenever a government or other party supplants a marketplace, it must generate some of the information either lost or newly-needed. (Schultze, 1977) In 1981, following a ten-year moratorium the United States government resumed leasing of publicly-owned coal. When the government designed this program, the goal was to guide the marketplace, rather than merely to respond, as a landlord, to the market's wishes. This goal has been modified somewhat, due both to the changing political climate and to the practical difficulties of implementing so ambitious an undertaking. Nevertheless, during this period of program design and implementation, part of the challenge of creating and using the necessary information fell to the professional modelling fraternity.

Jan 1, 1982

By Ashis Bhattacherjee, Subrata Chatterjee, Michael T. Dewey, Christopher J. Bise

In order to continue the advancements made during the past two decades in the reduction of the severity of accidents and injuries in underground coal mining, closer attention will have to be paid to the increasing number of accidents resulting in disabling injuries and lost time. With the increased emphasis on safety training reflected in the Federal Mine Safety and Health Amendments Act of 1977 (Public Law 96-1641, and on MSHA's current focus on the application of Job Safety Analysis, it appears that the acquisition, evaluation, and application of accident and incident data will take on an even greater importance. To manage this large amount of information will require a significant commitment of time and attention on the part of mine training departments. A USBM-sponsored research project is currently being completed at Penn State which focuser on the development of a model training program for mining. The program is based on five distinct steps which represent the coupling of a needs assessment with the program implementation. The five steps are: 1) database analysis, 2) workplace observations, 3) identification of trainable problem areas, 4) a library of training resources, and 6) the implementation of the program. In each of these areas, the microcomputer has proven to be a valuable tool for collecting, analyzing, and presenting accident and incident information. This paper will detail the manner in which microcomputers have been fully integrated into the model training program. Examples of applications at existing mines will also be discussed.

Jan 1, 1992

By David J. Kruse

The proper modeling of granular flow using discontinuum mechanics has the potential to be one of the most significant scientific advancements in the mining industry today. This paper will examine the status of discrete element technology, specifically focusing on current and future applications. The fundamentals of the Discrete Element Method (DEM) will be briefly introduced, as well as relevant design parameters. Various types of granular flow problems currently being solved using the DEM methodology will be presented. The results and potential benefits of these cases will also be discussed. All simulation results and figures used throughout this paper are from studies and designs preformed by the DEM group at Conveyor Dynamics, Inc. (CDI).

Jan 1, 2000

By Tsuneyoshi Funazaki, Takayoshi Nakamura, Keizo Miki, Takashi Imaishi

The underground portion (about 10 km) of Tokyo Wan Aqua-Line consists of eight shield tunnels connected with Kawasaki Man-Made Island in between, at four underground locations. The connection work had to fulfill strict precision and safety requirements in the ground about 60 m below soft seabed, but was completed successfully in May 1997. This report describes the connection work in detail, featuring the method of investigating shield machines’ relative positions, ground freezing method and connection mechanism and procedures. It also mentions the present state of Tokyo Wan Aqua-Line that was put in service on December 18, 1997.

Jan 1, 1999

By T. J. Cox

The Red River is located within the Sangre De Cristo Mountain Range in northern New Mexico. An approximate 12-mile segment of the river from the town of Red River to the village of Questa (Questa) includes several hydrothermal alteration zones. Alteration ?scars? formed as a result of rapid chemical weathering and physical erosion of pyrite-rich hydrothermally altered rocks. Storm water runoff from the scar drainages contributes metal-laden, acidic water to the river and creates a visible plume of discolored water in the river. Acidic runoff reduces the river pH from 7 to the mid 3s for at least 2 hours during large storms and the low pH water continues downstream. Runoff from scar drainages increases some metal concentrations in the river from below chronic ecological criteria to as much as two orders of magnitude greater than acute ecological criteria, and results in acutely toxic conditions for macro-invertebrates. A general improvement in the river?s water quality occurs downstream due to dilution from tributary inflow from non-mineralized watersheds, the natural buffering capacity of the river, and storm water controls at the Chevron Mining Inc. Questa mine.

Jan 1, 2011

By Michael J. Shulman

The DEAREX knowledge acquisition and engineering system is a teaching and exploration tool designed to facilitate the under- standing and development of expert systems by explorationists without the aid of a knowledge engineer and without recourse to expert system languages. To fulfill its objective, the DEAREX system considers the selection of exploration methods in desert areas. The system consists of three parts: 1. A tutorial which introduces the basic and selected advanced concepts of expert systems, 2. A sample program illustrating how an expert system works and can be used, and, most importantly, 3. A knowledge acqusition and engineering program which enables users to develop their own expert systems. The tutorial provides a brief and concise introduction to expert systems, a 10 rule exploration example which defines, explains and illustrates the basic concepts and design of expert systems, and a glossary of expert system terms including cross references. The sample program is a larger, self contained example of an expert system with some commentary illustrating addition- al expert system concepts and the role of the knowledge engineer in particularizing rules and ascertaining the knowledge base. Restricting itself to the selection of exploration methods in desert areas, the knowledge acquisition and engineering program questions the user and converts the answers into an expert system. Questions pertain to geology, infrastructure, availability of instrumentation, personnel, etc. Additional information may also included. In conclusion, some salient points concerning knowledge engineering toolkits, shells and knowledge acquisition capabilities such as contained in DEAREX are discussed.

Jan 1, 1992

By M. A. Pipke, C. M. Brown

The semiautogemus grinding circuit at the Utah Mines Ltd., Island Copper operation, located on Vancouver Island, British Columbia, is described. Since startup of the operation in 1971, grinding circuit throughput has been progressively increased from the initial design rate of 90 000 (99,000) to the current average 45 000 t/d (49,600 stpd) of porphyry copper ore. Key developments ad modifications in operating and maintenance practice that have contributed to this increase are reviewed.

Jan 1, 1987

By A. J. P. Durham

Two low water flux test covers were placed on acid generating waste rack dumps at the Kidston Gold Mine in Queensland, Australia The climate is semi arid with distinct wet/dry seasons. The present study was initiated to develop a cover system to restrict infiltration. The design of the cover required optimization of water storage and evapotranspiration. Instrumentation was installed on both dumps to measure infiltration, moisture conditions and climatic parameters. Field measurements over the last three years indicate that both covers are performing satisfactorily. Selection of the final cover for closure is described on the basis of these results.

Jan 1, 2000

By Terry Owen

Business development process. Throughout Cyprus Amax's early months in Russia, the company stayed focused on what was needed from a deposit for economic success. Cyprus Amax's reason for success in Russia is that all involved - its Russian partners, the workforce and expatriates - provided a focused effort that served the project as it worked through the tender process and the Russian regulations. The company developed an understanding of the regulatory process by working with solid, ethical partners. Infused into the Kubaka management structure were Russians with the knowledge to facilitate the process and a professional group of expatriates. Developing credibility and a solid rapport with the Russian mining authority was critical to the success of this venture. Identifying and gaining the trust of key Russian individuals was also critical during the early stages. Gaining their trust and building credibility was part of the process. These key Russians were brought to the United States to visit existing Cyprus Amax mines. These efforts proved valuable in building an understanding with the Russians about the kind of company Cyprus Amax is and the kind of efficient operations that it can run. This was a learning process for all parties. Fortunately, the company was dealing with intelligent and educated people.

Jan 1, 1997

By Charles E. Glass

As partial implementation of the Surface Mining Control and Reclamation Act of 1977, the Office of Surface Mining (OSM), Department of Interior, has requested each state to inventory hazardous abandoned mining areas within their boundaries. Primary interest is in such areas .as unstable waste-banks, subsidence and slumping, contamination of water supplies, and preservation of overall aesthetic qualities through reclamation. In addition to the concern expressed for abandoned mining areas, the legislation requires a complete inspection of operating mines quarterly and a partial inspection monthly. In Arizona copper has been mined for over 100 years and coal and uranium mining promises to expand in future years. The OSM requirement for a waste inventory and frequent monitoring of Arizona's large, widely spaced mines places a severe demand on limited personnel and operating budgets. Remote sensing by satellite provides an attractive and effective approach to aid the inventory and monitoring requirements of the OSM legislation.

Jan 1, 1979

By J de Cuyper, S. R. Rao, J. Leja, K. S. Moon, W. Freyberger

A prolonged grinding of sulphide ores in steel mills appears harmful to flotation recovery and selectivity whenever xanthates are used as collectors. Particles finer than about 10um show a pronounced decrease in floatability. A supposition was made that the cause of the reduction in floatability of ground sulphides is the presence of metallic iron abraded during grinding and deposited on the ground particles. Electro- chemical measurements were made of mixed potentials developed by different sulphide-mineral electrodes (galena, chalcopyrite, pyrite, marmatite, pyrrhotite) in xanthate solutions, without a direct con- tact or in contact with a metallic iron electrode. These measurements showed that without a galvanic contact between the sulphide and the iron, the values of mixed potentials were in the vicinity of the xanthate/dixanthogen redax potential. When contact with iron was established, the mixed potentials shifted towards the more negative reducing or cathodic values, The shift was greater the higher was the ratio of the surface areas: iron electrode to sulphide electrode. Further, the shift in mixed potentials was greater the more reducing were the conditions on the sulphide electrode. Chemical analysis of reaction products produced on the surfaces of sulphides and in the bulk solution showed that less thiosulphate was formed in all of the sulphide-xanthate systems and that more elemental sulphur was detect-

Jan 1, 1976

By Janusz S. Laskowski

Studies carried out over the last 10 years reveal that precipitating particles which may appear in alkaline solutions of long-chain amines and in acidic solutions of fatty acids exhibit clear isoelectric points around pH 10.6-1 1 for dodecylamine and around pH 2.5-3 for fatty acids. These colloidal species can accumulate at solid/liquid and liquid/gas interfaces and affect flotation. While the precipitate in solutions of fatty acids apparently can chemically interact with the mineral surfaces and is flotation-active if sufficiently long conditioning time is available, the cationic flotation of quartz in alkaline solutions is depressed by the colloidal precipitate. The experimental data available in literature on the adsorption, electrokinetic, contact angle and surface forces measurements in the solutions of the weak electrolyte collectors are analyzed and the role played by the precipitate is discussed. It is shown that these concepts allow for an explanation of the selective flotation of sylvite from halite with long-chain amines in potash ore flotation.

Jan 1, 1999

By Stewart R. Wallace

In the spring of 1959 while visiting the offices of the US Geological Survey (USGS) in the Denver Federal Center, I had a chance encounter with Paul Theobold, a former but, at that time, casual associate. Paul mentioned to me the results of his work on stream sediment geochemistry (Theobold and Thompson, 1959). Using panned concentrates, Theobold and Thompson had discovered a tungsten anomaly in Clear Creek and followed it upstream to its source on Woods Creek, a small tributary to the West Fork of Clear Creek. The specific source was a debris cone about 0.8 km (0.5 mile) upstream from the mine yard at the Urad molybdenite deposit. Because of the genetic and zonal association of tungsten and molybdenum at Climax, I found this very interesting. Accordingly, I related this information to Robert Henderson, general manager of western operations for Climax, and asked his permission to do some follow-up work. He, in turn, telephoned Frank Coolbaugh, the president of Amax, telling him of my interest and saying that, "Climax would take care of it." On my first visit to Urad, my companions (Dave Jonson, Bruce MacKenzie, and Dick Baker) and I were confronted by a "Cousin Jack" caretaker who made up for his diminutive stature by a "pistolover" that hung down almost to his knee and by a watchdog that was one-half wolf and one-half mean sled dog. We retreated discretely to Clear Creek and then climbed up the "back" side of Red Mountain by separate routes, across the ridge crest, and part of the way down the "front" side, sampling as we went. Although much of the ground was covered with snow, we found lots of puzzling but friendly looking rocks and the geochemical results were interesting. A geologic map of central Colorado showing the location of the Urad-Henderson and Climax deposits is shown in Fig. I.

Jan 1, 1991

By Fathi Habashi

WHILE HYDROGEN SULFIDE precipitates metal sulfides from aqueous solutions, other gases such as sulfur dioxide, carbon monoxide, and hydrogen, under certain conditions, precipitate the metals directly. This can be achieved at high temperature and pressure. Such processes are of great technical importance, since metals of high purity are precipitated economically in a powder form. As a result of the availability of such powders on a large scale. processes for compacting metal sheet and other mill forms directly from the

Jan 1, 1970

By Scott G. Britton

Many times during the construction of a project, whether large or small, the engineer will become involved with management of the work and workforce. In some cases, mine management will turn over the direction and responsibility of doing the work to the engineer. Because of this, it is important to know some of the basic principles of human resource applications- among other management concerns. This chapter, therefore, looks at the fundamental principles of human resource management. Three broad discussions are presented to the reader. These are: (1) organization, communications, and responsibilities of management; (2) analysis of worker motivation; and (3) supervisory leadership. Each topic encompasses the current thinking for coal mining and mining management. Much of the information in this chapter comes from Practical Coal Mine Management, by this author and published by John Wiley & Sons, Inc., which discusses in depth many of the ideas presented here. Interested persons are directed to this text for more information on management skills.

Jan 1, 1983

By Joseph E. Worthington

The Haile Gold Mine is one of the earliest gold discoveries in the eastern United States as well as one of the largest gold producers from that region. Gold was first discovered in the gravels of what is now known as Haile Gold Mine Branch in 1828 on lands then owned by Colonel Benjamin Hale (spelling not the same). Small placer workings were immediately started and it was not long before the surrounding residual soils and saprolites were also found to contain gold. Following the presence of gold in the residuum eventually lead to the discovery of the underlying gold-bearing lodes that actually outcropped in saprolite form where not masked by heavy vegetation or a thin veneer of Coastal Plain sand. The earliest attempts at production, immediately after discovery, utilized slave labor, washing gravel and residuum from leased tracts that were 15m (50 ft) square. Several at- tempts at small milling operations were made during the en- suing decades, but there was really no substantial or successful production until the 1880s.

Jan 1, 1990