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By Tracy Braun, Dan Lampshire

Over the past decade, heap leaching at Cortez has evolved from a rather small operation producing around 30,000 ounces per year of gold to an operation scheduled to produce over 400,000 ounces in 2004. Evolution and expansions in the heap leach operations are discussed including plant design criteria and some of the design features in the various facilities. Operating parameters and production forecasting are also discussed.

Jan 1, 2005

By M. J. Hrebar

This paper reviews large dozer stripping techniques and presents results of two field studies. The first is a seven-shift study of a contour block stripping operation where a Caterpillar DII is used as the primary stripping equipment. The second is a two-shift study of two Cat DIIs dozing blast cast material ahead of a dragline operation. Surveys and continuous time studies were used to determine production rates and as a basis for forecasting unit stripping costs in both cases.

Jan 1, 1994

By P. Arell, D. Folkes

This paper presents the basics of EPA’s Hazard Ranking System (HRS), which is used to evaluate sites for possible inclusion on the Superfund National Priorities List (NPL). The paper describes the surface water, ground water, air, and soil exposure pathways and how they are applied to mining sites. Key factors contributing to the site score include the likelihood of a release, waste characteristics, and the targets for each pathway. Waste volumes, definitions of landfills versus surface impoundments, and background concentrations are of particular importance to mining and smelting sites. Because of the presence of metals, large waste volumes, and observable releases, mining and smelting sites often receive high enough scores to be proposed for the NPL based on a single path-way. Neverthess, owners and operators can take steps to reduce the risk of being scored, and to reduce the potential for high scores.

Jan 1, 2004

By D. Greene

Close integration of mine planning and operation is a long-sought goal. Success is achieved in varying degrees depending upon mine complexity, size, and sophistication, but too often is more limited than desired. Despite tremendous strides in the development of computer-aided mine planning, digital plans usually must still be converted to error-prone paper maps and physical ground surveys for actual excavation and reclamation. However, advances in GPS, operator displays, and mobile computers now enable equipment operators to work directly from on-board digital plans. CAES offers reduced survey costs, faster field transition time and improved excavation accuracy coupled with faster, more informed decision making regarding key mining operations.

Jan 1, 1997

By William A. Faust

At Gold Fields' Chimney Creek Mine, major reviews of the reclamation and closure plans are done concurrently with the annual mine planning required for budget preparation. This review includes identifying and scheduling reclamation work that can be done within the next few years and development of associated costs. Longer term mine, leach pad and waste dump development are examined to take advantage of any design changes that can reduce ongoing reclamation or closure requirements and reduce costs. The success and cost effectiveness of past efforts are continually evaluated to determine the best methods for reclamation.

Jan 1, 1992

By E. Cetin

The authors describe the general problem of cut-off grade optimisation for multi-mineral deposits and outline the use of genetic algorithms for optimal cut-off grade schedules for deposits with up to three constituent minerals. Case studies are given and a comparison is made with Lane's multi- mineral cut-off grade algorithm.

Jan 1, 2002

By William F. Riggs

The characteristics of frothers can often be determined by the proper selection of various chemical groups. There are three basic groups utilized in the application of frothers. These are alcohols, polyglycol ethers, and polyglycols. Some of the chemical groups are separated in subgroups. Each chemical group provides particular characteristics which affect load support, bubble diameter, water retention, air dispersion, and kinetics of froth formation. These chemical groups may be preblended in various percentages to optimize frother characteristics for a particular ore deposit.

Jan 1, 1986

By G. W. Luxbacher

With the advent of acid rain legislation included within the Clean Air Act Amendments of 1990, a great deal of uncertainty with regard to price, source and production quantities has been cast into the coal market. Powder River Basin and other western coals continue a rapidly accelerating migration eastward, South American coals move into the northern markets, states propose legislation to assist utilities in complying with the new regulations in hopes of maintaining their own coal industries, while some utilities question the long term availability of eastern compliance coal. Any major coal producer must make decisions now to assure their continuing presence in the market place; several companies have adopted a strategy to acquire eastern compliance reserves while others have invested in technology to compete as a low cost producer. This paper discusses some of these options in light of the uncertainties of the market place, from an eastern coal producer?s viewpoint.

Jan 1, 1992

By Dale C. Matthews

Pressure oxidation of refractory gold ores is becoming more popular in our environmentally sensitive society. This paper will discuss some specific process problems and solutions involved with starting up and operating an autoclave circuit.

Jan 1, 1991

Overland conveyor belts that exhibit tracking problems under loaded and unloaded conditions can be tested to' determine the root cause of the mistracking. Moveable conveyors are more prone to mistracking due to structure alignment requirements. In addition, belting quality, splice straightness and carcass condition has a dramatic effect on the performance of a belt in relation to tracking. Methods are discussed that are proven to reduce belt mistracking and improve the operational reliability of the conveyor system.

Jan 1, 1995

Maptek, an international development software company, released version 3.2 of its Vulcan three-dimensional mining and geological software package. This latest release is expected to give clients better graphics performance and improved overall solutions. In addition, the company also released the NT version of Vulcan for Unix and personal computers. More than 800 code changes have gone into the 3.2 release, the Lakewood, CO-based company said. Many of these changes were in response to requests from Maptek's customers. Others have been motivated internally by the company to achieve better performance in its Envisage graphics interface. The introduction of hot keys and user-defined menus makes Envisage a more flexible interface and a more productive working environment. A new animation option provides new ways to enhance the organization and display of data. The animated data can include point, string, grid, triangulation and photographic-draped data. The shaft-mapping facility is also included in version 3.2. It enables the cylindrical view of the shaft to be unwrapped and displayed on the screen while the data remains in its true world coordinates. Major upgrades to Vulcan include underground blast design and geotechnical modules. The new blast design module allows the user to develop a ring design in any plane defined by the stope layout. Radial and offset holes can be developed. User-friendly editing tools make adjustments to the initial design a simple task. The user defines the plotting and reporting of rings and plot style templates allow flexibility in reporting. New features in the geotechnical toolbox include options to create daylight windows and pitch lines on the stereo nets. Geotechnical databases can be directly updated from the interpretation of the stereo net. Direct annotation of the symbols on the net is now possible and the stereo net display can be customized. Improvements to the documentation and links within the text have made the on-line help easier to navigate. Maptek also released the NT version of Vulcan soft- ware. The comprehensive design of the software pack- age for Unix and personal computers provides a three-dimensional geological modeling and mine planning system within a natural graphics environment. Users who require the power to manipulate extra- large and complex data sets will still be served by the Unix platform. Users who handle small-to-large datasets can now choose between Unix and personal computer platforms. The NT version will appeal primarily to companies that already have a personal computer network. Response to industry feedback was the basis for developing the NT version. "We want to ensure that our clients receive the optimal product for their needs," said Nicolas Simon, vice president of Maptek in North America. Some advantages of the NT version include: ? Most mining professionals are familiar with the personal computer platform. ? All of the familiar personal computer tools are now available to Vulcan users. ? Resource modeling tools that previously required the powerful Unix workstations have been brought into the personal computer environment. This will help mining companies save money. From a binary data point of view, the personal computer NT version is compatible with other platforms, such as SGIIDECIHPISUN, allowing integrated personal computer and Unix environments For more information, contact Cherie LeDoux, Maptek, 165 So. Union Blvd., Suite 777, Lakewood, CO 80228, fax 303-763-4921, e-mail: info@maptek.com, Internet: http:llwww.maptek.com.

Jan 1, 1997

By William L. Hodgson

HOARDS was written to fill the needs of an active minerals explorer. It permits retrievals using a number of spatial functions as well as direct relational logic, and enables statistical analysis within the system. Specified for use by non-EDP oriented staff, HOARDS also offers functions to subset, transform points to polygons of influence, and to calculate polygon overlap, enabling ready and efficient conversion of databases containing point oriented sample data to area/volume mine planning format. Both the design and implementation to date, and proposed enhancements are discussed.

Jan 1, 1979

By Joseph Corvetti

This paper is of conceptual nature. The authors present their idea of creating an integrated and intelligent excavation design system. Research work has just been started and the results will be addressed during presentation of this paper. The authors are currently engaged in a pilot study and expect to build a feasibility prototype expert system (establishing the numerical-cognitive coupling in excavation design) by the end of this year.

Jan 1, 1996

By L. Reyes-Bozo, R. Ginocchio, A. Godoy-Faúndez, C. Sáez

Relationships among mining industry, society and environment have been historically complex due to its environmental impacts. In the Chilean mining industry, repetitive and small spills of fuel during maintenance of machinery have been adsorbed by desert soils and sawdust to control environmental pollution. The froth flotation is the main technology to recover specific mineralogical species from sulphide ores. Flotation reagents are expensive and representing an environmental risks due to its physics properties. Our objective was to investigate the feasibility of applying bioremediation as a cost-effective alternative technology to physical-chemical treatments and to evaluate the efficacy of biosolids as foaming agents. Our results show that the bioremediation is feasible by use of the autochthonous microbial communities and biosolids could be used as new environmental-friendly organic reagents. This research discloses a sustainable bioremediation process and industrial ecology model based on these two successful cases.

Jan 1, 2011

By J. H. Jennekens

INTRODUCTION "Most people would probably agree that some degree of government control and regulation is essential in modern society, and it will likely continue as an important part of our social organization for the foreseeable future. But most of us tend to be ambivalent about it. In one situation or another we are likely to see government commitment to social benefit programs or regulatory devices either as an expanding encroachment on the freedom of the individual or as an undue interference with private enterprise or with the rules of the market place. But even where there is agreement as to the desirability of government initiatives, either in general or in a particular context, it by no means follows that there will be approval of the mechanisms or procedures used or the means of carrying them out." The above statement is taken from a 1980 Working Paper of the Law Reform Commission of Canada prepared in connection with its study of the exercise of administrative law in Canada and the practices and procedures of administrative tribunals. The Atomic Energy Control Board (AECB) is one such administrative tribunal, and as the federal nuclear regulatory authority, it is responsible for licensing the production, possession and use of nuclear materials, equipment and facilities and enforcing compliance with licence conditions governing the health, safety, security and environmental aspects of the activities involved. Although the AECB was established 35 years ago with the passage in August 1946 of the Atomic Energy Control Act, like many administrative tribunals its role and functions and the regulatory process which it applies have evolved significantly during this period. The changes which have taken place over the years reflect not only the vast scientific and technological developments which have occurred but also the marked differences between contemporary society and the social milieu of the mid-1940s. However, the basic philosophy of nuclear regulation in Canada and the underlying principles of the regulatory process have changed very little. Certainly, the process is far more open in terms of the general public, it has become appreciably more comprehensive and systematic in terms of the depth and extent of both the pre- and post-licensing technical evaluations which are conducted and the ensuing compliance program. Furthermore, it now applies to the whole of the nuclear fuel cycle as well as the industrial, agricultural and medical applications of radionuclides. Nevertheless the following fundamental principles remain unchanged: a. primary responsibility for achieving high standards of nuclear safety and environmental protection in the design, construction, commissioning and operation of nuclear facilities resides with the licensee; b. the credibility of the nuclear regulatory process depends not only upon its technical correctness and practicability, but also upon acceptance by the public-at-large of its perceived effectiveness and efficiency; c. regulatory criteria and principles should be concise, clearly stated and understandable; d. regulatory decision-making should be based upon stated criteria and principles taking into account pertinent scientific and technical facts only; e. fairness and impartiality must characterize all regulatory decision-making; f. the regulatory process should be subject to a comprehensive periodic review and evaluation to ensure that it continues to produce the desired results at justified costs. EXPLANATORY NOTES The mere statement of a set of principles is a relatively simple task. Far more difficult is the explanation of what these principles mean in practical terms. To stipulate that a licensee bears the primary responsibility for achieving and maintaining high standards of nuclear safety and environmental protection may be regarded by some as an attempt by the regulatory agency to evade the responsibilities assigned to it. However, this is not the case. It is unrealistic for anyone to claim that a licensee only complies with accepted norms of public and occupational health and safety and of environmental protection because of the fear of prosecution. The vast majority of citizens conduct their affairs in a proper manner not because there

Jan 1, 1981

By S. Komar Kawatra, Henry J. Walqui, Timothy C. Eisele

Population balance models were used to model the grinding action of industrial scale coal pulverizers. Experimental work was conducted with two different coal samples to determine the values of the appearance and selection function. These functions were determined for vertical mills by using s 6-inch by 10-inch laboratory roll mill to represent the action of a vertical mill. Two very important operating variables were identified for vertical mills: feed rate and roll spacing. Factorially designed experiments were used to analyze .and quantify the effect of these two variables. The models were then adapted to represent changes in operating conditions by incorporating the effect of the feed rate and roll spacing effects. This resulted in a simulation model able to respond to changes in operating conditions, by providing corrected predicted values for the product size distribution.

Jan 1, 2002

By Gregory R. Wagner

As you know, NIOSH is the part of the United States Public Health Service with responsibility for conducting and supporting research leading to prevention and control of occupational diseases and injuries. Some years ago, NIOSH went through a process of identifying and leading occupational health and safety problems in the United States. Candidate problems were evaluated in terms of the number of people affected, the importance of the effects, and how amenable the conditions are to preventive interventions. Lung diseases were ranked first on the resulting list. Diseases from mining continue to contribute substantially to this unfortunate position of prominence. The work of the Generic Center is one of many answers to this critical problem. Although the research is often expressed in terms of dust characterization or dust control, the reality is that high dust levels are much like high blood pressure. No one cares about hypertension per se. We are concerned about the consequences of exposure to untreated high blood pressure--heart disease, kidney disease, and stroke. Similarly, if dusts were truly only a nuisance, there would be little justification for the diverse research program supported by the Bureau of Mines or by NIOSH. But mineral dusts do cause a range of significant health problems: pneumoconiosis, bronchitis, and emphysema. The research supported by the Center is aimed at doing something about them. Within a public health approach to occupational health, we have a hierarchy of interventions. Primary prevention of problems is prevention at the source: solving a problem before it affects a worker. What we call secondary prevention is an attempt to identify health problems at a sufficiently early stage that some intervention will interrupt the disease process or the development of significant impairment. Tertiary prevention refers to rehabilitation of the worker who has already suffered significant loss of function. At NIOSH, and in the Generic Center research programs, the focus is on primary prevention. Basic investigations into those things about specific dusts that promote or reduce toxicity is critical for our understanding of how to prevent disease. Also, the search for engineering solutions to reduce or control dust generation is essential to solving problems of dust over-exposure. But until the engineers create the foolproof safe environment, it will also be necessary to discover better ways to identify the earliest markers of disease. To do this, we must explore and explicate the basic mechanisms of disease through laboratory investigations as well as human observation and physiologic testing. The unique opportunity provided by the Generic Center program and highlighted in this diverse program over the next few days is that these efforts are being carried out in multiple disciplines concurrently. Also, there are periodic small and large gatherings such as this one where investigators have the chance to get together, formally present papers, and informally stimulate each other's progress towards disease prevention. To ignore the potential for this cross-cutting interaction would be a significant loss. To take full advantage of it is potentially revolutionary. I recently pulled out a book I hadn't read since I was an undergraduate. It specifically concerns the nature of intellectual ferment surrounding the development of the concept of a sun-centered rather than an earth-centered universe in the sixteenth century. The book is about more than developments in astronomy: it is a discussion of the nature of scientific revolutions. Scientific revolutions result from the brilliance, insight, and good fortune of the few superimposed on the evolutionary work of the many. They both cause and reflect significant itellectural and social ferment. For example, the revolutionary work of Copernicus in recognizing the limitations of the concept of an earth-centered universe reflected contemporaneous developments in optics, mathematics, physics, economics, and philosophy.

Jan 1, 1991

By W. G. Courtney

The prevention of frictional ignition with a ripper-type continuous mining machine using conical bits was investigated in the laboratory using cutter-drum-mounted water sprays. Results indicated that frictional ignition during dry cutting of sandstone with conical bits was readily obtained even at low drum rpm, while wet cutting with a carefully-designed water spray nozzle located behind the bit substantially reduced the likelihood of frictional ignition. However, the orientation and operation of the spray nozzle is critical and involves almost no margin for error. A Lee-Norse 265 ripper drum has been modified to include durable water seals and is presently being field tested underground.

Jan 1, 1987

By Malcolm J. McPherson

There have been numerous recorded cases of mine explosions being initiated by falls of roof. The actual mechanism of the ignition has often been unknown. One possibility is incendive frictional sparking, particularly when the falling rock contains quartz. Another possibility that has received little attention is the increase in temperature of the air due to adiabatic compression under the falling roof. This paper analyses that possibility and concludes that falls which are extensive in plan area but not necessarily of great thickness of falling rock can, indeed, produce temperatures in excess of those required for the ignition of coal dust or methane.

Jan 1, 1995

By T. D. Dreger

In the spring of 2009, Suncor Energy Inc. technical personnel saw an opportunity to improve planning and mining of overburden material in order to address aggressive construction goals and increased mining complexity. By tying together current and historical equipment performance, geological model information, and material observation in the field new operating elevations for the shovels were developed. At the same time, methodology of recording and reporting overburden movement through the Modular Mining DISPATCH system was changed. The result of this first stage of improvements was an increase in construction-grade material available at the face. The personnel involved realized that other opportunities were available to build on the initial successes and establish processes that would stand up to attrition and experience levels. A cross-functional technical team was assembled to identify ways of further improving workflows around overburden mining. Some of the opportunities realized include greater alignment between planning, reporting and operations as well as development of reporting tools that help steward Mine Operations to the plan. All of which have resulted in Suncor meeting or beating its forecast overburden targets. The cross-functional technical team continues to seek out new and better ways of doing business so Suncor can continue to deliver on its commitment of outstanding performance and results.

Jan 1, 2012