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By Leonard Harris, Rosa H. Harris

An important part of doing business today in the mining industry, especially overseas, involves community assistance programs for the people who live around the mining areas. The purpose of such a program is to build mutual cooperation and respect that will allow the company and its neighbors to live and work in peace. To do this, it is necessary to form associations or foundations and work in a joint venture fashion. The authors discuss in some detail the outline for setting up such programs and the important role that women, in particular, can play in them.

Jan 1, 2001

By Y. C. Kim, I. S. Roditis, P. K. Medhi

The strongly skewed grade distributions and the need to estimate the local recoverable reserves in a selective mining environment are the two problems that ordinary kriging (OK) cannot easily handle. With the recent introduction of the non- parametric, distribution-free technique of indicator kriging (IK), the above problems can be solved. This paper describes the result of performance evaluation of IK in an open-pit gold-silver deposit. For performance evaluation, the predictions of local recoverable reserves using IK were compared with the actual reserves based on blasthole information. The IK estimator, although a bit optimistic (or overestimating), performed very well in predicting the total recoverable ounces of gold from each panel on a test bench. The OK estimator was also used to try to predict local recoverable reserves, by treating each panel as either waste or ore, depending on the panel's average grade. Under this criterion, OK was found to be quite biased and pessimistic (or underestimating).

Jan 1, 1988

By André G. Journel

As opposed to graphics applications in medical sciences and mechanical engineering, computer imaging of the subsurface faces a severe problem of data shortage. Most graphics softwares include an interpolation algorithm aimed at producing slick graphic output, irrespective of the attribute being interpolated, the quantity and quality of the data available, and what the map is intended for. It is suggested that the power of modern computers be also used in providing representations of the subsurface that accurately reflect actual spatial variability and the large variety of soft information available beyond hard data. Since any subsurface representation is uncertain, a measure of that uncertainty should be provided which can be used for risk analysis.

Jan 1, 1992

By Steve Kral

The list of environmental issues facing industry in general, and the mining industry in particular, has placed greater emphasis on the concept of risk assessment and risk management. In informal terms, risk can be defined as the chance of injury, loss or damage. More formally, it is defined as the probability of an occurrence and its consequences. In simple terms, risk assessment involves three questions: What can go wrong? How probable is it to go wrong? If it goes wrong, what are the consequences? Experts on the subject of risk assess¬ment and management met in St. Louis, MO in October 1992 to discuss the extensive and innovative technology that has been developed in this arena. Each agreed that a consistent framework can be used to approach risk assessment/ management considerations in siting and design alternatives, as well as when considering financial aspects of mine development. And the environmental planning process for mines, as well as planning for operation through closures, will rely more heavily on risk assessment and management techniques. Risk assessment is a tool to assist engineers, scientists and managers make better, defensible operational decisions. A realistic and probabilistic risk analysis, coupled with a sound financial model, can combine a large set of alternatives and criteria to arrive at a defensible decision. Organizers of this regional SME conference believe that mining professionals should become fully conversant with risk assessment techniques and approaches because this arena provides opportunities to develop more rational decision-making techniques. Current health risk assessments rely heavily on Environmental Protection Agency (EPA) approaches. Several speakers and papers show how this approach has been applied to a variety of topics. Two major advantages come forward when applying risk assessment techniques to environmental clean-up options for contaminated sites. They are the selection of practical options and cost-effective alternatives. A probabilistic risk assessment provides results that can be directly related to clean-up costs. It has been shown that small reductions in risk are obtained for large increases in cost after a certain threshold value is reached. A preferred, practical clean-up alternative that provides permanent solutions can be selected based on a probabilistic assessment. Here are summaries of some of the papers presented at the meeting.

Jan 1, 1993

By Harry Sutcliffe

INTRODUCTION The need for discussion of Owner-Engineer-Contractor relationships in tunneling arises from the increase in costly and time-consuming litigation. The paper examines the objectives, motivations and responsibilities of each party, discusses some common causes of claims in underground work, and makes some suggestions for improvements. The viewpoint and bias are those of an engineer. If a subtitle were required for the session, "Sharing the Risk" would be appropriate. Sharing the risk is an important aspect of Owner-Engineer-Contractor relationships because when a risk is shared, all parties have an incentive to minimize it. The System It would be shortsighted not to recognize that the system is wider than the Owner, the Engineer and the Contractor. There are many outside influences which affect the day-to-day behavior of each party: Financing agencies Insurance agencies Bonding agencies OSHA and other safety legislation The Federal Power Commission The Public Utilities Commission The General Accounting Office

Jan 1, 1997

By Michael Honerkamp, Clemens Mann

A quarry is not a static, but a dynamic structure that greatly affects the appearance of the surrounding area. Excellent planning is required today to cope with this continual change. In this paper several case studies are presented where computerized three-dimensional visualization has been successfully applied.

Jan 1, 1996

By M. C. Williams, T. P. Meloy

With the increasing power of computers to simulate and control processes in the mineral industry, predicting the potential use of computers in the minerals field is not a hazardous enterprise, but predicting the timing of their use is. Like the railroad industry, technology invades the mineral industry, rather than being an industry like electronics that creates technology. Because of this invasive nature of computer technology in the minerals field, this paper predicts what will be possible to do effectively and economically with computers in the mineral industry. Moreover, this paper explores the problems of using the emerging computer technology in the mineral industry. For example, if not now, it soon will be possible to control the output of a mineral processing circuit - high grade, high flow or a mixture of it - to meet the daily market conditions and to sell each day that daily "mill" output as "mill" futures on the commodity market. Finally, suggestions are made which may be done to prepare the industry for the computer revolution in the mineral industry.

Jan 1, 1993

By Sol Ribakoff

With the utilization of most of the "high dam" sites for hydro-electric power and the completion of most railroad routes, many tunnel contractors were extremely doubtful that tunnel driving would continue to be an important element of heavy contracting. Experience has proved otherwise. The ever-increasing need for rapid transit and for pollution control have generated, and will continue for the indefinite future to generate, a very high level of tunneling activity. At the same time, the costs of construction have traveled an upward curve in the tunnel industry, as in all other types of construction. As a result, Owners, Engineers and Contractors have sought ways and means of constructing more economically through the development and use of labor-saving devices and techniques. The development of mining machines and lasers has contributed tremendously to such economy. Before giving you a contractor's viewpoint on Owner-Engineer-Contractor relationships in tunneling, it may be well to provide some background as to matters which give rise to that viewpoint. Construction contractors in general, and tunnel contractors in particular, have always had to contend with the physical environment in which the work has to be accomplished. However, when a building contractor has constructed his foundation, and certainly after he has "closed in", he deals thereafter with known physical conditions, or at least with conditions which he could reasonably have estimated would occur. Except, perhaps, for the hazard as to earthquakes, he has cleared Nature's threats. A tunnel contractor, however, must give thought to what the physical environment may do to his job, each and every day that he is driving a tunnel. The general consensus among tunnel men is that Mother Nature is much more likely to be murderous than motherly. Without attempting to make too much of

Jan 1, 1997

By T. N. Patra, Sanjeeva Latchireddi, B. K. Mishra, Sravan K. Prathy

The motion of grinding balls has been the subject of study since 191 9 when Davis published the first treatise on this subject. Subsequently came the notion that knowing mill power draft, using Bond equation or others, is sufficient to do an analysis of grinding. Next, population balance models provided accurate scale-up from small laboratory size mills to very large plant size mills. However, this success was not repeated when dealing with semiautogenous grinding mill. The study of charge motion with the discrete element method provides support and answers to such issues. Besides providing an accurate picture of charge motion in large mills, the method begs the investigator to study grate and pulp lifter equally critically with fluid dynamic principles. Hence, in recent years, the field of comminution in grinding mills is advancing on a firm footing.

Jan 1, 2005

By Raj K. Singhal

This paper is a report on a task force study dealing with many facets of computerization. The primary mandate of the task force was to examine the software and hardware currently available for application relating to reserve estimation, mine planning, economic evaluation, equipment selection, production scheduling and composite mine simulation and to evaluate how adequately the software fulfills the user needs in surface mining of oil sands and coal. To meet its objectives the task force consulted extensively with the users, developers and suppliers of hardware and software. The paper outlines the approach taken by the task force to fulfill its mandate, summarizes its findings and presents some pointers which might be useful to others considering this type of evaluation.

Jan 1, 1986

By Dario DeBenedictis

The speaker intends to review the positions expressed by the Owner, Engineer and Contractor representatives, respectively, with emphasis on the legal aspects of the relationships among said parties, and particularly dealing with the preparation and interpretation of specifications generally, and changed conditions clauses particularly, and the handling of claims arising thereunder.

Jan 1, 1997

Diamond wire rock cutting is the most widely used technology in carbonate stone quarrying owing to technical performance and block face quality. Interest is also growing for siliceous deposits. This paper deals with the problem of optimum wire utilization under restrictions regarding a set of variables and parameters. A computer program of general applicability has been set up with the aim of studying the most suitable combination of technologies and the effect on the technical and economic results of bench geometry, overall quarry yield, market -stone value, quarry size as well as the quantity, productivity and price of human and material resources and their organization in the elemental working cycle. Two quarrying problems are considered as significant instances a granite and a travertine quarry. The results are illustrated and discussed.

Jan 1, 1989

By Dae S. Young, Eleonora Widzyk-Capehart

A quantitative estimation of the size distribution of rock fragments is extremely important in mining, metallurgy and other geotechnical fields. This paper presents a new approach to the analysis of fragmentation. The method combines the practicality of digital image processing of the rock surface with the theoretical volume calculations based on the principles and laws of fractal geometry. The final volumetric distribution curve is compared with the results from traditional sieving indicating close agreement.

Jan 1, 1996

By Scott G. Britton

Thin-seam mining presents unique challenges when management or economic conditions require significant productivity increases. These challenges can be further amplified depending on such factors as labor unions, federal and state regulations and market characteristics. This article explores the turnaround situation occurring at Tanoma Mining Co. (TMC), a medium-sized, underground coal mining company in central Pennsylvania. The company has used a systematic approach of improving management controls and direction, labor relations and communications to improve its cash flow from negative to positive within a projected five-year span. An intensive upgrade-rebuild-replacement program for mining equipment and systems has also been established to support other management activities. Discussion Thin-seam coal mining is an industry within the broader industry of coal mining. Thin seam mining faces the same cost pressures and engineering problems as its higher-seam competitors, without the advantages of moving volume per foot of extracted material. To stay at economic parity with others requires additional creativity within the management team to extract higher productivity gains from the existing workforce and mining systems. The Tanoma operation is a deep mine in Indiana County, PA, about one hour northeast of Pittsburgh. Coal is extracted from the Lower Kittanning "B" seam. It lies about 91 m (300 ft) below the surface and averages 0.9 m (I ft) in height. Continuous mining units using mobile bridge conveyors or shuttle cars

Jan 1, 1991

By T. C. Rao, D. D. Patil

The fishhook effect, wherein the recovery of fine particles in the underflow increases with decreasing particle size, has been observed in hydrocyclone classification. A systematic study was carried out to determine the factors affecting the recovery of very fine particles to the underflow. Attempts were made to identify factors, i.e., design and operating variables, that affect the size at which this phenomenon occurs. Experimental results show that the sizes at which the fishhook effect occurs is mainly a function of feed size distribution and solids concentration and is less dependent on the design variables.

Jan 1, 2002

By A. I. Johnson

The pegmatites of the Black Hills of South Dakota are the coarse-grained differentiates of the Harney Peak Granite. The Harney Peak Granite was intruded into the Pre-cambrian schist and quartzites and resulted in the Black Hills uplift. In the outer adzes of the granite intrusion occur the pegmatites. In the zoned pegmatites, representing the most highly differentiated portions of the parent magma, occur most of the minerals produced from pegmatites. These are of economic importance and they are the subject of this paper. The various mineral products will be taken up separately.

Jan 1, 1978

By Stephen J. Reynolds

Arizona's geologic history is complex, resulting in a diversity of rock types and earth materials, including those of commercial interest. Regional variations in geologic history gave rise to three geologic provinces and an inequitable distribution of both metallic and nonmetallic mineral wealth. The Colorado Plateau is largely composed of flat-lying Paleozoic and Mesozoic sedimentary rocks and late Cenozoic volcanic fields and sedimentary deposits. Associated resources include gypsum, halite, sylvite, clays, specialty sand, flagstone, volcanic products, and aggregate. The adjacent Transition Zone features a large expanse of Proterozoic rocks, economically important Devonian and Mississippian carbonate rocks, and Tertiary volcanic and sedimentary materials. Nonmetallic resources in this province include facing and dimension stone, aggregate, decomposed granite, chrysotile asbestos, gypsum, clay, barite, fluorspar, zeolites, and limestone used for lime, cement, and railroad ballast. The Basin and Range Province has the most complex geologic history and, therefore, the most diverse assemblage of industrial mineral occurrences. These include halite, gypsum, clay, aggregate, decomposed granite, diatomite, zeolites, perlite, pumice, kyanite, limestone, marble, stone, and others. In addition, young stream deposits yield vast quantities of sand and gravel, Arizona's most economically important nonmetallic mineral commodity.

Jan 1, 1987

By Carl D. Wood

Traditionally, when one considers the optimization of a flotation circuit, the scope of work focuses on a review of unit process equipment. This usually includes topics such as grinding ball typed, grind size, classifier efficiency, mill liner design, chemical reagent addition rates, alternative chemical reagents, on-line process analysis, and automated control strategy. However, since very few companies can afford the capital expenditure needed to completely automate the processes, the flotation operator remains as a critical link in optimization of the circuit. Therefore, upgrading of operator skills and knowledge through training must be considered as equally as important as unit process review. This paper will review some concepts and approaches to innovative operator training. INTRODUCTION Consider for a moment the fantastic changes that have occurred in process automation at many flotation plants during the last several years. Flowmeters, density gages, and on-stream analyzers now routinely measure process conditions and effect control strategy. These functions had until recently been entrusted to human flotation operators. Now with a little stretching of the imagination it is possible to envision a plant where very little human intervention would be required. However, when one begins to calculate the capital cost required to fully install automatic equipment, it quickly becomes apparent that many parts of flotation plants will continue to require skilled, knowledgeable operators to ensure successful operation. Additionally as these automatic systems are put into place, the operator's duties become increasingly complex. Therefore no flotation plant can be considered optimized without upgrading each operator's skill and knowledge to match the technology utilized. BACKGROUND At Henderson, one of the hardest steps towards the optimization of operators was to realize that present level of operator skill and knowledge was not sufficient. Since Henderson had a track record of producing the highest quality molybdenum concentrate in the world, it was difficult to accept the idea that change was needed, or even possible. This realization came about as Henderson began a program to modernize the cleaner plant circuit. Henderson utilizes a complex cleaner flotation circuit involving multiple stages of flotation, with a counter- current routing of flotation tailings. Since start-up in 1976 Henderson had relied upon next-day laboratory analysis techniques, that provided an after the fact measurement of process. Hour to hour process control was implemented by the operator, the basis for the operators' control decisions was primarily the individual operator's experience and "feel'. Bench marking of current flotation technology indicated that on-stream analysis was a proven state-of-the-art method for improving process control. An Outokumpu Courier 30 analyzer was purchased and installed to provide real-time analysis of critical cleaner plant flows. The analyzer quickly began to provide valuable assay information, allowing the metallurgists to develop specific target values for important flotation variables. However due to the complexity of the circuit, the analyzer information showed that a problem was usually caused when several targeted parameters went out of range simultaneously. This made it difficult for the operator to determine just where to implement the proper corrective action. It became apparent that to take full advantage of the new analyzer information each operator would have to become proficient at understanding the material balance of the entire circuit. TRAINING PLAN CONCEPTS With the goal of giving each operator a working knowledge of a circuit material balance the following concepts were applied to develop a training plan: - Most operators were high school graduates, but had fairly weak mathematical skills, and had very little experience at metallurgical calculations. - The training would have to address a wide range of topics from basic fundamentals to complex material balance. The basic sequence decided upon, was to present a fundamental topic to the entire group, break into small groups to work a “hands on'”case study example of that topic, and design the case study results so that they could be combined to highlight a major portion of the material balance concept.

Jan 1, 1993

The modelling process described in this paper was developed in order to assess the feasibility of various investments options for the exploitation of a lignite deposit located in the Prefecture of Florina, Greece. The model uses as evaluation criterion the net present value. It is based on the characteristics of the reserves and relates the decision making with numerous technical, economic and environmental factors. The examined alternatives include the construction of a new thermal power plant at the mine-mouth, the fuel supply of already existing power plants located at relatively long distances and the fuel exports in neighboring countries. Moreover, the feasibility of post-poning the exploitation of the lignite deposit and preserving its reserves for exploitation in the future is also assessed. The paper also includes a short discussion about the environmental constraints related to the supply of lignite produced from Florina mines to power plants that were designed and constructed for burning fuel mixtures with different quality characteristics.

Jan 1, 2005

By Stanislaw Wasolewski

Computerized systems for ventilation parameters monitoring which are used in Polish coal mines provide the ventilation staff with a great number of measuring data. These data can be used to get knowledge about dynamic properties of ventilation process and disturbances affecting its state. This is necessary to create a reasonable concept of mine ventilation control system and make a practical application of such system. In the paper a method of ventilation process identification with the use of measuring data from monitoring system is described. Computer analysis of time series including statistical, correlation and frequency methods are applied to estimate dynamic properties of ventilation process and its disturbances. Using the Fast Fourier Transformation (FFT) algorithm the parameters of the process have been obtained which can be efectively used in a system for mine ventilation control.

Jan 1, 1991