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By Jerry W. Danni, John E. Hardaway

Corporations today must comply with an ever growing number of complex and increasingly stringent environmental laws and regulations. An environmental audit program is an effective means in which to uniformly and systematically assess compliance, and to assure management that environmental liabilities are being minimized. This paper describes the design and implementation of Homestake Mining Company's environmental audit program, which has as its primary focus the objective verification of compliance with external requirements and internal good management practices. Major elements of the audit program discussed in the paper include: pre-audit preparation; on-site audit activities; and the post-audit report.

Jan 1, 1992

By T. M. Jones

This paper outlines the development of the theory of controlled district recirculation and indicates the advances in understanding and technology which have enabled a major change in established ventilation practice. An insight is presented into the possible future use of controlled district recirculation as acceptable practice in mine ventilation planning.

Jan 1, 1987

By Stephen Day, Maria Falutsu, Gary Coulter

Open-pit mining began at Red Dog in 1989. Mining is expected to continue past 2030 but closure planning is an ongoing process. Geochemical studies of rock and tailings were begun in 1996 as part of development of closure plans to address leaching of metals and ARD. The deposit has many different primary and secondary sulfur minerals in amounts that preclude the use of conventional geochemical characterization methods. This paper will describe development of a specific chemical method to estimate the speciation of sulfur and classify wastes according to reactivity.

Jan 1, 2000

By William P. Shinn

The site of Pittsburg from the first knowledge by white men of its location has been regarded as a position of great strategic importance.

By Robert P. Edwards, Brian C. Flintoff

Crushing plants (multiple stage) are an integral part of most conventional comminution circuits (ball mill, rod mill - ball mill). Although conventional circuitry is now the design exception, there are still many older, and some newer plants that include crushing in the process flowsheet. In most of these installations the operating objective is to maximize throughput at some minimum product size, in an effort to balance the comminution load between crushing and grinding. To achieve this goal, while avoiding production losses due to overloads, generally requires the use of automatic control strategies. This paper reviews the crushing plant control problem and describes several approaches that have been successfully implemented in different plants.

Jan 1, 1992

By Michael D. Sopko

This paper describes the project implementation from financing, through the engineering and construction phases, mine and process plant commissioning as well as operating experience realized to-date. The single line flowsheet used to process the lateritic nickel ore to a 75 percent nickel matte is presented with emphasis on the main pyrometallurgical operations. These include a rotary dryer, a unique reduction kiln, a 45 000 kVA electric furnace and two Pierce-Smith type converters. Associated infrastructure facilities and services necessary to sustain the 11 300 tonnes (12 500 short tons) per year nickel production rate are also described.

Jan 1, 1979

By L. W. Stanger, Erich U. Petersen, William J. Tafuri, Donald M. Hausen, Douglas N. Halbe

Gold mineralization at the Mercur Mine was controlled primarily by structure and secondarily by lithology in Mississippian-age sedimentary rocks. Gold was localized where Sevier-age high angle northeast-striking faults are intersected by younger northwest-striking fault zones. The Lulu Graben is a northeast- striking fault zone composed of a south-dipping master fault coupled with subsidiary or antithetic faults. The Twist Fault zone, a sinuous, low-displacement , north-striking zone of fracturing, bisects the graben. Large- tonnage disseminated ore bodies formed east of the Twist Fault zone within silty, thin-bedded, bioclastic carbonates. West of the Twist Fault zone, gold was restricted to rock near peripheral faults surrounding a subvertical collapsed pipe developed within the graben. An overlying thick carbonaceous shale capped the ore zone. Presence of abundant limited- displacement faulting and of hydrothermal jasperoid is associated with cartonate-hosted disseminated gold. Conversely, increased fault displacement and widespread brecciation are associated with reduced dissemination of gold into normally receptive carbonates.

Jan 1, 1990

By D. H. Warren

This presentation we hope will provide you with an orderly approach co mine and surface plant closure taken from our experience over the past several years on six different projects within the intermountain states. There is no magic to the approach. It is basic common sense and yet it is interesting how many of the specific details are overlooked due to the individual complexity of each site. Our attempt here is to share some of the issues that have confronted us on these six sites. Please recognize that it is impossible to be all inclusive. Of the six sites we have drawn from; two are mine, mill and smelter sites dating back to pre-1900, one is an industrial site dating back to the early 1900s, two are mill and concentrator sites dating from the late 1940s and one is a mining district site dating from the late 1800s.

Jan 1, 1989

By Kadri Dagdelen

The definition and shortcomings of traditional cutoff grades are discussed. . The concept of optimum cutoff grade policy which maximizes the Net Present Value (NPV) of annual cash flows coming from a mining project is introduced within the basic framework outlined by K. F. Lane. Several examples are used to demonstrate the shortfalls of cutoff grade policies obtained by various heuristic optimization techniques. An algorithm to obtain an optimum cutoff grade policy which maximizes the NPV of a project is given and described in detail.

Jan 1, 1992

By M. J. Sapko

The Bureau conducted, through joint funding with the Colorado Mining Association, large scale oil shale rubble fire tests to investigate flotability characteristics and different methods of extinguishment. Ignition of large rubble piles was easily accomplished. Foam blankets could be used to control surface flames. The results of these large scale tests confirmed that water was effective in extinguishing deep seated oil shale fires but not particularly efficient. It took up to 1.7 times as much water to extinguish a fire as anticipated on the basis of a simple cooling model, assuming 100 pet utilization.

Jan 1, 1989

By W. Hennig

Efforts to define sustainability indicators are continuing in the mineral extracting industry and sector research institutions. Comprehensive ‘sets’ of economic, ecological and social sustainability indicators for the minerals industry are a necessary precondition for rationale-based negotiations with stakeholders from society. These tools alone, however, will not suffice in a delicately balanced economy-ecology -social well-being equilibrium with ever shifting valuation of different variables. Individual interests and emotions and also ideologically motivated positions of diverse stakeholders are gaining momentum. The minerals industry therefore has to develop beyond the rational pro-arguments for mining in the form of sustainability indicators also proactively its ‘soft skills’ to deal with expectations, fears and outright anti-mining bias, if it wants to retain the ‘social licence’ to continue.

Jan 1, 2005

By Jay A. Bowden

In April of 1990, Homestake Mining Company began a 5,100 m (16,700 ft.) exploration drift from the Homestake Mine in Lead, South Dakota. The drift starts from the mine's 6800 level, nearly 2,100 m below the surface, and extends north to further explore occurrences of gold discovered by surface drilling. Access to the North Drift for men and materials and for disposal of waste rock is limited to the Homestake Mine's #6 Winze, which serves as the major production shaft for the deep levels of the mine. This paper will discuss the successes and challenges encountered while managing a tunneling project 2,100 m below the surface and from an active mine.

Jan 1, 1993

By Chris C. Sundberg, Ronald E. Heuer, Stanley L. Paul, Peter M. Douglass

Use of prestressed concrete cylinder pipe (PCCP) for pressure tunnel liners is gaining popularity with contractors, engineers, and owners. This paper presents loading considerations and a beam-spring computer model approach to tunnel liner analysis, together with ultimate strength (US) and service load (SL) procedures for liner design. The US procedure is best suited to check for adequate liner strength under extreme loading conditions. The SL procedure, based on conventional pipeline design practice, is considered more appropriate when addressing crack control and serviceability under normal working load conditions. Other design and construction considerations are discussed and a design example is presented.

Jan 1, 1987

By R. W. Smith, R. K. Mehta, X. P. Zheng, A. M. Raichur, M. Misra

Experimentation was per formed on the flotation of apatite and dolomite separately using anionic collectors in the presence of Mycobacterium phlei. Also, the flotation of mixtures of dolomite and apatite in the presence of anionic collectors and in the absence and presence of the bacterium were studied. It was found that M.phlei functions as a depressant for both minerals. However, it functions as a better depressant for dolomite than for apatite. Experimentation was extended to two different Florida dolomitic phosphate rocks. In this investigation a concentrate grade of less than 1.0% MgO was achieved with a 75% P2O5 recovery.

Jan 1, 1999

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 T. E. Garnar

Heavy mineral mining has been a small, but important Florida industry over the past sixty years. Early geologic history of each deposit is similar up to point of deposition in alluvium, deltaic sediments, or along shorelines. Later geological development through reworking and concentration is different for each deposit. The Trail Ridge deposit was formed by reworking Citronelle sediments of the Lake Wales ridge. Post depositional leaching of iron from ilmenite makes Trail Ridge an important source of titanium minerals for TiO2 pigment manufacture. Research leading to the separation and sale of by-product heavy minerals from Florida deposits has been important in maximizing profitability. Advances in mineral dressing technology will lead to future mining of lower grade reserves. Future needs for heavy minerals seem certain to expand, with increased activity in exploration and development of mining operations.

Jan 1, 1972

The sixth annual conference of the Mineral Economics and Management Society (MEMS) was held Feb. 27 through March 1 in Boulder, CO. This year's event was attended by more than 100 academic, industrial, government and other professionals interested in mineral economics and materials management. With about 250 members worldwide, this not-for-profit society seeks to promote scientific and economic analysis of current relevant issues. This year's program was sponsored by Alcan, Bateman Engineering, Cyprus Amax Minerals, J.P Morgan, Knight Piesold LLC and Newmont Gold. The conference's technical program consisted of six sessions. These included "Financial tools for a changing world," "Access to minerals," "Comparing North and South America," "Environmental issues in today's world" and "Transporting minerals." The program was concluded with a panel discussion titled "National minerals policies in Asia." In addition, a student papers session was held, in which students were given the opportunity to compete for a $1,000 award. The following is a brief review of the technical pro¬gram.

Jan 1, 1997

By Mark A. Anderson

INTRODUCTION The accomplishment of a well engineered design, and the realization of efficient plant operation cannot be achieved without weaving a web of safety consciousness from the beginning of the project. When the plant becomes operational, and throughout its life, responsibility safety will rest with the client or operator. Recognition of this understanding does not reduce the importance of the engineering and construction contractor's role, but merely puts the responsibility where it belongs. A project which has had little or no operator input during the early stages of design is almost certain to have serious work place safety, health, and environmental problems in spite of the fact that all MSHA and OSHA design requirements were met and the engineering was performed using accepted practices. DEFINITIONS The author has a personal preference in safety definitions that begins and ends with simplicity. If the safety criteria, program, and rules are confusing or complex, the results will soon become obvious. Confusing and complex are the key elements in the avoidance of responsibility and if punitive is added to the list, a brew exists which breeds accidents, illness, and poor performance. A safely designed and operated plant is one that a worker can journey to each day; leaving that person and his or her family with the above average expectation that the person will return healthy, emotionally intact, and hopefully a little wealthier. If the objective or results of a planned or existing safety program don't fit the definition. then the reader is probably contemplating a very sophisticated

Jan 1, 1986

By Raymond E. Krauss

The McLaughlin Mine is based on a world class epithermal gold deposit located in the coastal thrust fault of northern California, about 1 12 air km (70 air miles) north of San Francisco. Owned and operated by Homestake Mining Co., the McLaughlin deposit contains about 18 Mt (20 million st) of gold ore at an average grade of 5.2 g/t (0.152 oz per st), or about 93 t (3 million oz). The area was identified as a gold target by Homestake in early 1978. Drilling confirmed it to be a commercial deposit by 1980. The mine was then planned, engineered, built and brought into production by March of 1985. The deposit was historically a part of the Knoxville District. It was mined for cinnabar, which was used to produce mercury for use in recovering gold and silver in the Mother Lode and Comstock districts. At that time, the mine was called the Manhatten and later the One Shot Mine. It was worked for more than 100 years, producing about 76,000 flasks of mercury without any awareness of the presence of economic concentrations of gold. By 1978, the site was largely disturbed and entirely unreclaimed.

Jan 1, 1990

By G. E. S. Valadão

This paper is concerned with studying the dewatering behavior of three samples of iron ore products. The objective is to improve the industrial filtration performance by taking into account the laboratory results. Mineral samples came from the Iron Ore Quadrangle in the state of Minas Gerais, Brazil. These samples represent products from the industrial processing of hematitic ores. The samples have almost the same chemical and mineralogical compositions, but they have different size distributions and different specific surface areas. The filtration tests were performed using a modified Büchner funnel apparatus. The results indicate that size distribution and specific surface area have significant influences on dewatering behavior. For Sample 1, the addition of flocculant and/or surfactant was not essential to improving filtration performance. For Sample 3, the cake porosity and the cake thickness were influenced by the addition of the flocculant. On the other hand, the simultaneous addition of flocculant/surfactant decreased the cake formation time and reduced the cake moisture. For Samples 2 and 3, it was also observed that the industrial operation could be improved by taking into account these laboratory results. Key words: Dewatering, Iron ore, Hematite, Filtration, Flocculation, Surfactant

Jan 1, 2003