Search Documents

By F. N. Kissell, H. K. Sacks

This study examines the accuracy of area sampling for measuring the dust exposure of mining machine operators in coal mines. The specific objective of this research was to find locations where an area sampler might work better than earlier studies have indicated. The results show that fixed-location area sampling cannot accurately predict the dust exposure of a machine operator, even when the best fixed location is sought, the fixed location is quite close to the operator and the bias due to the dust concentration gradient is corrected. Industrial hygienists have known for many years that area sampling is unsuitable for measuring air contaminant exposures in the workplace. Near contaminant sources, the dilution air and the contaminants are not evenly mixed. Therefore, when workers are near contaminant sources, exposure measurements must be taken from the worker's breathing zone to be accurate.

Jan 1, 2003

By Michael Harris, David Mosch

The numerous small high grade gold and silver deposits of the Front Range Mineral Belt have been uneconomical because of the high costs of mill construction, transportation, and smeltering. Processing of these ores must be simple, cheap, with satisfactory recoveries, and be environmentally acceptable. Vat leach with direct electrolytic recovery satisfies these parameters. A battery of testing was conducted utilizing bottle and bucket tests. A five ton vat leach with direct electrolytic recovery gave excellent results while a five ton heap leach proved impractical due to channeling.

Jan 1, 1987

By Regina N. Tempel, Timothy E. Eastep, R. Craig Ford, Bryce R. Roming, Geoff Clothier, Maggy F. Lengke

The Climax Mine, near Leadville, Colorado treats acid drainage in a lime neutralization chemical treatment system. Chemical treatment has been successful in reducing the concentration of metals to below surface water discharge effluent limits, but lime usage has not been optimized. A geochemical modeling approach has been developed to increase the efficiency of lime neutralization. The modeling approach incorporates two steps: (1) calibration, and (2) calculation of amount of lime needed to increase pH and remove metals. Results of our work quantify the lime treatment process and improve our ability to predict overall water quality.

Jan 1, 2000

By J. C. Yingling, R. Kumar, J. Sottile

The capability for on-line measurement of the quality characteristics of conveyed coal now enables mine operators to take advantage of the inherent heterogeneity of those streams and split them into wash and no-wash stocks. Relative to processing the entire stream, this reduces the amount of coal that must be washed at the mine and, thereby reducing processing costs, recovery losses and refuse-genera¬tion levels. In this paper, new ap¬proaches for optimal control of the segregation process using time-se¬ries models and empirical distribu¬tions are presented and demon¬strated using field data.

Jan 1, 2000

By Jennifer B. Leinart, Otto L. Schumacher

JIM ARNOLD: Our next speaker is Otto Schumacher. He's president of Western Mining Engineering in Spokane, Washington. His company offers services in the area of mining feasibility analysis and publishes Mining Cost Service. Otto's talk will be "Are Metallurgists Overpaid?" [laughter] I know one that's not. [laughter] OTTO SCHUMACHER: I really think it's kind of a dirty trick for Doug to put me up here and pose that question since I'm a mining engineer. However, it's probably most appropriate that a mining engineer address the question because I can be more objective than the rest of you. [laughter] SPEAKER. Otto, do you promise to say something nice about metallurgists? [laughter] OTTO SCHUMACHER: I'll see how much time I have. [laughter]

Jan 1, 1998

By D. G. Millette, A. J. S. (Sam) Spearing

The design of a cost effective backfill system involves many aspects and various inputs from different engineering disciplines. Backfilling is a very significant mining cost and efforts need to be made in the design stage to maximise efficiency and flexibility whilst minimising costs. The aspects that need to be considered include the following: Required fill performance underground Peak and average fill tonnage requirements Backfill scheduling in the mining cycle Material selection, testing and preliminary costing Plant design and storage needs Infrastructure requirements Implications on surface waste/tailings disposal and costs Total backfill costs In order to produce a cost effective and efficient backfill operation, a multi-disciplinary project team is required that should include the following skills and functions: Mine Planning Rock Engineering Metallurgy Mechanical Engineering Environmental Health and Safety Tailings Disposal/Waste Management This paper discusses the above and indicates important aspects that should be considered.

Jan 1, 2001

By C. Timothy Shaw, Michael Karmis, Hans de Ruiter

The Society of Mining Professors/Societät der Bergbaukunde was established during a meeting hosted by the Montanuniversität, Leoben, Austria, in 1990. Since then, the Society has primarily functioned as a European entity of senior academics in the mining engineering discipline. The Society is considered the natural successor of the historic Societät der Bergbaukunde, formed in the early 18th century and recognized as the world’s first international scientific society. At the 14th Annual General Meeting of the Society, in Milos, Greece, 2003, a decision was made to examine the role of the Society in global minerals education, to reassess its vision and membership guidelines and to develop the future direction of the organization. A special Planning Subcommittee developed a plan of action to allow the Society to transform and position itself as the premier global voice of the academic minerals disciplines and to lead the effort of restructuring minerals education. The new vision calls for reconstituting the Society as a vibrant global society, representing the majority of minerals academics and making a significant contribution to the future of the minerals disciplines. This paper will present the history, vision, goals and action plans of the Society to help ensure that the necessary scientific, technical, academic and professional skills are available for the sustainable supply of minerals to mankind.

Jan 1, 2005

By V. L. Zajakowski, J. D. Gargulak

The current political climate has forced multinational cement manufacturers to consider technology that minimizes GO, emissions. Along with this environmental issue, individual manufacturing facilities are under constant pressure to increase productivity and lower costs. The use of processing or functional additions can help address these difficult demands by maximizing the extender content in blended cements. Recently, cement standards have been modified such that additions can be employed to improve quality. By using these "cement performance enhancers," the cement manufacturer can maximize extender content of cement thus optimizing plant economics, while meeting local quality standards and minimizing greenhouse gas emissions.

Jan 1, 2003

By Daniel Hodouin, Claude Bazin, Sami Makni

Computer systems, installed in mineral processing, are designed to accumulate massive amounts of real-time data. Frequently these data are only partially processed because of the lack of adequate methods and the limited accuracy of mineral processing sensors. Methods are proposed to estimate missing data and reconciliate sensor data on a real-time basis. They are based on dynamic extension of steady-state techniques such as the node imbalance minimization or the least-squares mass balance adjustment techniques. The methods are illustrated for simulated and actual flotation data. Their data upgrading ability could be used to improve process monitoring, control and optimization.

Jan 1, 1993

By R. L. Grayson

As a followup to a USBM-sponsored research project, the authors utilized the knowledge-base structure and system concepts from a Sun Sparcstation-based worker-scheduling system of the mine-management support system to develop a PC-based application. The new software adopts the nested-window concept to facilitate data collection and modification on personnel, including their availability and work priorities during a shift. The system can optimally allocate manpower on a work shift and can delineate supervisory training responsibilities. The various components of the software, including enhancements made to the original system, are described in detail.

Jan 1, 1997

By Jonathan J. Owen

We will describe modifications to air-sparged hydrocyclones (ASH) that enhance collisions and reaction of wastewater contaminants with sparged gas. These new ASH-based reaction chambers are combined with flotation tanks that are designed to optimize separation of bubbles and particles from water. In combination, these systems have achieved unprecedented removal of contaminants from industrial wastewater and process water while requiring smaller footprints with lower capital and operating costs. Real-world examples of chemical and nonchemical water treatments that demonstrate the outstanding flexibility and applicability of these systems are shown. Design enhancements that resolve the operational problems of traditional ASH are discussed.

Jan 1, 1999

By D. J. Dunn

Grinding balls, simple in shape, are actually sophisticated machine components and essential elements of mineral grinding mills. Their physical properties and quality must be adequate to achieve design life and grinding mission with few failures. Consistent properties and freedom from breakage are essential. Size, mass, hardness profile, chemistry, and microstructure are important variables that should be designed, specified, controlled, and verified to achieve optimal mill performance. Failure to specify ball properties in detail or failure to obtain required ball properties and quality can cause milling productivity losses and excessive costs that could endanger a milling operation's survival in the competitive mineral industry.

Jan 1, 1990

By S. O. Yuan, R. L. Grayson

As a followup to a USBM-sponsored research project, the authors utilized the knowledge-base structure and system concepts from a Sun Sparcstation-based worker-scheduling system of the mine-management support system to develop a PC-based application. The new software adopts the nested-window concept to facilitate data collection and modification on personnel, including their availability and work priorities during a shift. The system can optimally allocate manpower on a work shift and can delineate supervisory training responsibilities. The various components of the software, including enhancements made to the original system, are described in detail.

Jan 1, 1998

By V. J. Matta, A. A. Pincheira, I. A. Reghezza, Ch. J. Vergara

The growth of solvent extraction in Chile has been astonishing during the last years and has been established as a very successful technology. However, there are still limitations that must be improved, mainly, the problem of carry over from one phase to the other and the losses of organic reagent associated with the crud formation. These are problems that our company has been taking care, solving them with high efficiency and low costs, allowing important increases in the copper output of our plants and capital savings by means of the optimization of the use of nonproductive units in the SX plants.

Jan 1, 1998

By Vanessa M. Torres

Diagnostic leaching tests provide a good indication of gold deportation in its various occurrence phases. With the results of these tests, possible flowsheets for difficult ore treatment can be established for further evaluation and plant operation can be optimized. The use of this technique can be extended, including heap leach evaluation and complex copper-gold ores. The results on the use of diagnostic leaching tests in gold ores from Companhia Vale do Rio Doce (CVRD) are presented and discussed, as well as the methodology to select steps and interpret results used at CVRD Technology Center (Sutec).

Jan 1, 1998

By Daniel R. Hack

Spatial relationships among physical 'and chemical properties pertinent to economic development of sand and gravel deposits have been little studied. Models need to address trends or zonation of material properties applicable to mine evaluation and planning or as a guide among deposits for use in regional assessment Models can then be utilized to design sampling programs to optimize additional data acquisition. Development of a preliminary methodology in the lower Boise River Valley, western Idaho, will utilize historical and recent data from a terrace-gravel deposit. Classical statistics and techniques of spatial data analysis will be evaluated as a precursor to formal geostatistical evaluation.

Jan 1, 2002

By R. Schmidt

The computational fluid dynamics (CFD) technique was used to analyze and optimize the design of the dynamic air classifier integral to Raymond® Bowl Mills. Flow patterns and particle behaviors were modeled in the RB Bowl Mill equipped with various classifier designs. These CFD simulations resulted in the development of a hybrid turbine classifier that has now been field-tested, yielding significant improvements to both mill throughput and product size distribution. This paper demonstrates the viability of CFD as a tool for air classifier design and as a technique that can be extrapolated for use with other pulverizer and classifier arrangements.

Jan 1, 2004

By A. Aubut, A. Proulx, O. Tavchandjian

Results obtained from conditional simulations and multiple indicator kriging were compared in the assessment of two different mining methods proposed for the extraction of the down-dip extension of a nickel-sulfide ore body located in the Thompson mining camp, Canada. An enhanced turning band simulation algorithm, supplemented with an unfolding technique, was used. A floating stope optimization process was used to effectively compare tonnage and grade figures. A calibration exercise was also conducted in the upper portion of the ore body. This study demonstrates that conditional simulations provide better spatial models for conceptual mine design and capital budgeting decisions.

Jan 1, 2004

By J. Ainsworth, W. Trudel, L. Schutz, C. L. Bolin

Newmont mine geologists have added substantial economic value developing over 1,150 tonnes into quality surface and underground gold reserves since 1986. However, the recent 5-year gold price slump from $387 to $262 per ounce has shifted mine geologists focus to optimizing open pit profitability and developing high-grade, high cash flow and low capital development underground reserves. More than $65 million projected revenue has been added to the Gold Quarry south layback following multi-departmental model reconciliation investigations. Kriged mine polygon construction, controlled blast heave and high-quality geologic advice in selective mining will have multi-million dollar beneficial impacts.

Jan 1, 2002

There are multiple stages in a mining operation that a mining engineer has to draw polygons to be used as operation guidelines. These polygons are drawn by hand and based on engineer?s experience. However, having automatic procedures for forming the shapes can increase the quality and decrease the efforts required. These shapes need to be homogenous in grades and rock types so that the quality and dilution of material sent to the plant can be estimated with the good approximation. In this paper, a clustering algorithm with shape control is introduced which can provide reasonable guidelines for all the aforementioned shapes by manipulating its parameters. At the end, implementations of the algorithm on a small part of a gold deposit with different mining strategies is presented and evaluated based on homogeneity of grade, rock types and determined destinations as well as the shape.

Feb 27, 2013