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By G. T. Lineberry, W. J. Wiehagen, L. L. Rethi

This paper discusses a practical method for enhancing the performance of mining work crews. The method, described as the Work Crew Performance Model (WCPM), seeks to define performance variability within similar tasks of an underground work crew. Key components of the WCPM include: •job definition through task analyses, •the ranking of job elements by perceived cost consequence, •observational techniques to establish performance baselines, and •cost linkages between adherence to task procedures and measures of consequence for noncompliance. The components of this model emphasize a reliance on learning from a veteran work force and using that information to reinvest in strategies to enhance safety and efficiency. These strategies are not limited to technological efforts but include consideration of the so-called "soft-skill technologies, " aimed at reducing variability in individual performance and at effecting a continuous improvement in overall system effectiveness.

Jan 1, 1996

By M. Guzman, S. B. Thais, M. F. Obispo, M. R. Arribasplata

One of the greatest environmental issues related to the development of the mining activity is the generation of Acid Mine Drainage (AMD). Many methods have been developed for AMD treatment, being wetlands a good option for heavy metal removal. In this sense, the implementation of artificial wetlands for the treatment of mining effluents would seem to be an environmentally friendly alternative. In this paper, we present the results on the elimination of heavy metals (Cu, Zn, Pb and Fe) using two Peruvian native species such as Schoenoplectus californicus (C.A. Mey.) and Phragmites australis (Cav.) Trin. Ex Steud. The results show that Schoenoplectus californicus preferentially removes copper (82 and 90%), lead (88 and 92%) and iron (28 and 69%), whereas Phragmites australis removes copper (68 and 87%) and zinc (53 and 95%). Likewise, it is observed that the Schoenoplectus californicus mainly retains the ions in its root, copper (89%), zinc (84%) and iron (76%). While the Phragmites australis accumulates iron (62%) and copper (74%) in the steam and root part respectively

Mar 2, 2022

By H. Evans

It is well known that iron-ore pellets are considered one of the best blast-furnace burden materials used today. The demand for pellets is demonstrated by the increase in pellet output from one million tons in 1955 to approximately 37 million tons in 1964. This growth continues as new plants are placed on-stream each year. The consumer generally specified (1) the acceptable content and range of chemical constituents, (2) a minimum strength determined by some standard testing procedure, (3) the size range of pellets, and (4) perhaps a measure of reducibility.

Jan 1, 1966

By Ralph M. Barnett

It is no longer a question of "If" mining operations will meet standards and regulations set by various governing bodies and the demands of citizen groups. Legislation is fact. The needs of citizens are becoming more of a integral part of mining company planning. "Open Planning", regardless of some frustrations it provides, is working. Climax, AMAX Chemical and AMAX Exploration are successfully employing several citizen involvement techniques in exploration and feasibility study phases of planning for potential new mines.

Jan 1, 1978

By William S. Eaton

Managing a mine or mineral processing operation in today's environment presents many unique challenges to mining companies. In recent years, headlines around the world have publicized major incidents such as those associated with the Marcopper Mine in the Philippines, the cyanide release in Guyana from the Omai gold mine and numerous other mishaps associated with mining. These notable upsets were due to engineered system failures, either during normal operations or as a result of uncontrollable events. There fore, many mining firms are attempting to assess their overall risks and establish some priority for expenditure of limited operational and environmental budgets. Failure of an engineered component can have dire operational consequences that affect profitability until repair or replacement can be completed. In addition, there may be significant environmental consequences associated with the engineered system failure. This, too, may affect profitability for an extended time or even the viability of an operation. An engineered risk assessment (ERA) can support a mining company's efforts to cost effectively manage environmental risks associated with the operation of its facilities. The ERA approach also provides information about the current condition of engineered systems. This ERA approach provides a systematic review of the risks of an engineered system failure and the possible associated environmental consequences at mining company facilities. This approach has been successfully applied to many industries and types of engineered systems (Barneich et al, 1996; Whitman, 1984; Power and Tomkins, 1974; Keeney, Nair, and Kulkarni, 1979). This approach evaluates all mining and mineral processing facilities located at a single site and compares them with similar facilities located at multiple mine sites. The ERA approach has been applied to a mining, milling, smelting, leaching and refining operations. These assessments can be part of a comprehensive environmental program to aid in the recognition and cost effective management of the potential environmental risks associated with the operation of facilities. ERA results support plan-

Jan 1, 1997

By G. T. Adel

The selective recovery of fine particles by flotation has been a long-standing problem in the mineral processing industry. Fundamental studies carried out at Virginia Tech since 1980 have suggested that many of the problems encountered in separating fine particles can be alleviated by using significantly smaller air bubbles than those used in conventional flotation processes. The main advantage of using smaller bubbles is found in an increased recovery rate, which can be attributed to an improved bubble-particle collision efficiency. This concept has been applied in column flotation as a means of improving flotation kinetics. A computer simulator has been developed to better study the effects of various parameters on flotation column performance. The simulation results suggest that the use of small bubbles and tall columns improves the recovery of fine particles while a judicious use of wash water greatly improves product quality. Information collected as a result of this analysis has been applied in developing scale-up relationships for column flotation.

Jan 1, 1989

By Ahmed I. A. Salama

The problem of estimating separation characteristics by utilizing mass distributions of feed and products is considered. The separation characteristics include mass yield and partition curve. The cases of mass balance and partition functions balance are identified. The developed techniques can handle the cases of two- and three-product separation. Actual data are utilized to demonstrate the proposed techniques.

Jan 1, 1992

By Kadri Dagdelen

Production scheduling of an open pit mine is one of the most important steps in open pit mine planning. The production schedule of a mine defines the distribution of cash flows and as a result directly influences the net present value and overall economic feasibility of a project. It is becoming more and more critical to obtain an exploitation schedule of a deposit such that highest possible returns are achieved from a project. As the mining industry mines lower and lower grade ores, production scheduling is becoming a key item which can make or break a project. Although the need to plan and operate a mine with an optimum production schedule has been obvious for some time, the methods used to obtain such a schedule have not been. There is not a single, mathematically proven, optimum mine production scheduling algorithm which is widely accepted and used today. In an attempt to determine a production schedule which is optimum, a new algorithm was developed. This algorithm, in theory, is based on the lagrangian concepts of mathematics and in practice is based on the parameterization concept of mining. This paper describes the fundamentals of this newly developed algorithm.

Jan 1, 1986

By H. F. Hennigar, D. L. Pawson, E. J. Foell

Results of an analysis of abyssal benthic megafauna based upon review of nearly 250 hours of videotape and 2149 bottom photographs are presented, and the utility and limitations of such analyses in deep sea biological studies are discussed. The images were acquired at depths of 4400-4800 m during a resource assessment cruise aboard the RV Prospector using a unique, deep-towed, television telemetry system coupled with 35-mm photography. The data review was carried out in support of NOAA efforts to provide adequate environmental baseline information before industrial exploitation of nodule deposits and concurrent monitoring begin.

Jan 1, 1991

By L. E. Baker, M. J. Leck

OSIRIS is a continuous monitoring system for respirable dust which has been specifically designed for mining and related industries. By using the latest microprocessor technology, OSIRIS provides a sophisticated dust measuring system which is a cost effective alternative to regular gravimetric sampling. The system is certified intrinsically safe for use underground. Up to eight underground OSIRIS sensors can be controlled and monitored by a single IBM PC computer located at the mine surface. This computer provides continuous and instantaneous information about the dust concentrations at the sites being monitored. Information is available in tabular and graphical form. The paper gives details of proving trials of the OSIRIS system in some UK coal mines. During these trials, adjacent OSIRIS sensors placed on the same underground roadway cross-section gave virtually identical results. Throughout a good correlation was obtained with conventional gravimetric dust samples. The OSIRIS equipment proved both reliable and easy to operate. OSIRIS was designed and developed by the Safety Engineering Laboratory of the UK Health and Safety Executive. It is now available commercially and is being

Jan 1, 1987

By V. K. Paruchuri, J. D. Miller, J. Nalaskowski

An understanding of forces responsible for the stability of dispersions of colloidal particles when interacting with each other in aqueous solutions is of great interest academically and industrially. When water-soluble polymers are adsorbed onto colloidal particles, various effects on the stability of their suspensions can be expected ranging from steric stabilization to bridging flocculation. The possibility of detailed characterization of such systems using direct measurements of interaction forces between particles can help in further improvement of existing technologies of solid-liquid separation. An atomic force microscope (AFM) colloidal probe was used to measure the interaction forces between a silica sphere and a silica substrate in the presence of water-soluble polymers. Poly(ethlene oxide) (PEO) with three different molecular weights (7,000, 43,000, and 63,000), each with a very narrow molecular weight distribution, were used in this study. The interaction forces measured with the AFM over an extended time scale are discussed in terms of the adsorption kinetics measured through in-situ FTIR/IRS measurements.

Jan 1, 2003

By Yuusaku Tominaga

A flexible expert system for a personal computer has been developed to take countermeasures for prevention of emergency in underground coal mines. The system makes a diagram to estimate maximum airflow rate of a specified branch such as coal face or advancing face, etc. under the conditions of opening regulators set in any two different branches, by computer simulation. The system approximates the ventilating condition underground by using both measured values and safety factor derived from the rules in the system. The probability of happening gas explosion, spontaneous combustion and mine fire underground is shown on a display and countermeasures in a data base in the system are selected according to a confidence factor. When it is recognized in the system that either safety factor or confidence factor of countermeasure has a small value, the system sends information relating to reasoning in the system to registered human experts by computer communi¬cation and facsimile. The replies in file transfer from the experts are stored in the system and reconsultations for estimation of underground condition are started automatically. As the replies in facsimile are shown on the display, user inputs new rules and, values for reconsultation. It is shown that the system is available to take better countermeasures as the condition' of a network in coal mine is changed by mining day by day.

Jan 1, 1992

By V. B. Achanti, A. W. Khair

This paper deals with the effects of various bit geometric parameters on the failure characteristics of rock material. Improving the rock-cutting efficiency of continuous mining machines has proven to be an interesting research topic during the last few decades. In the current study, an automated rotary rock-cutting simulator, duplicating a continuous miner, was used to study these parameters in the laboratory. The improvement of bit performance in terms of its life, cutting efficiency, dust production and energy consumption has drawn widespread attention. Research has demonstrated that optimizing bit parameters can result in efficient fragmentation of rock. Indiana limestone rock material was used in this study. The bit tip angle, bit tip size, bit spacing, depth of cut and cutting velocity of the rotary drum were varied to investigate the failure characteristics. The cutting pressure, penetrating pressure and the depth of cut were monitored on the simulator during the cutting process. Airborne dust and settled dust were measured for each experiment. Then, the specific airborne dust and specific energy were determined for each type of bit. Triaxial tests were carried out to correlate the failure angle of the rock in the static case to the dynamic cutting process failure. The physical and mechanical properties of the rock were also determined to assess their influence on the wear characteristics of each bit.

Jan 1, 2000

By R. W. Utley, J. Carr

The tremendous growth in grinding mill size and horsepower during the 70s demanded advancements in gear cutting technology and equipment for the 80s. A new standard in gear cutting machines is now used to generate-cut large open gear sets to over 12.2 m (40 ft) in diameter at an AGMA quality level much higher than the accepted levels a short five years ago. The precision of the resulting gear set assures maximum tooth contact with the resultant longer gear set life.

Jan 1, 1987

By Alexander N. Winchell

"Location. The Cuyuna iron district extends from the region of Kimberly, near the Center of Aitkin County, Minnesota, south-westward through Deerwood, Ironton, and Brainerd, across Crow Wing and Todd counties, across the Mississippi River, and for an unknown distance farther southwest in the same direction. It is known that the Huronian rocks, in which the ores of the Cuyuna district are found, reappear near the western border f Minnesota, but no ores have been found in this region. The district has a length of more than sixty miles, but the more important portion as now known 'is confined to Crow Wing County in an area which is less than thirty miles in its longest dimension. The commercial headquarters for the district are in the city f Brainerd, on the Mississippi River.History. The discovery of iron ore in the Cuyuna district was accomplished with no aid from surface outcrops, but solely through the use of the dip needle. The mantle of glacial drift overlying the iron formation varies from twenty-five to 359 feet in thickness, and it was by means f the magnetic attraction of the iron bearing rocks that their presence was discovered with the dip needle by Cuyler Adams, about 1895. The general geologic map of Minnesota, published by the State Geological Survey in 1909, showed the extension of the Huronian rocks of the Mesabi district passing through this area. Two years later, Leith published a sketch showing the hypothetic extension of the iron bearing formation through the same area. The first drilling was done in 1903, near Deerwood, Minn., by Cuyler Adams, and exploration was continued to the present time in increasing amount. The Northern Pacific Railway extends throughout the length of the district and affords an easy outlet for the ores. The Soo Line Railway completed a spur into the district in 1910. Both roads carry the ore to the docks at Supe¬rior, Wis., the average haul being about ninety miles. Shipments began in 1911, the Kennedy mine being the first producer. By 1918, the number of shippers reached twenty-seven, with a total output of nearly two and one-half million tons for that year."

Jan 1, 1920

By M. R. Stokes

Over the recent years there has been an increase in the application of retreat mining on longwall faces as mine operators strive for ever greater productivity. The purpose of this paper in then to review current practice as a starting point and then move forward to discuss the future geometry's that a longwall face may take. Single and double production zone three roadway faces are assessed. All possible configurations of three roadway faces are defined. Unsuitable configurations are rejected after analysis of broad ventilation issues. The remaining configurations are then assessed on an operational basis, this includes: limits on retreat synchronisation, structure of centre gate, floor bulging and equipment installation. The remaining viable configurations are then further assessed on ventilation issues, this includes: provision for gas control/gas fringe, face climate and balancing of face flows. Possible face climate is assessed using numerical simulation of the various configurations, the predicted dry/wet bulb temperature and predicted levels of heat stress indices are given and discussed in detail, along with face flow balancing. The necessary conditions required for the successful operation of a double production zone three roadway face system are formulated, together with conclusions as to the possible level of application.

Jan 1, 1997

By K. F. Unrug

Martin County Coal Corporation is located in Martin County, Kentucky in the Appalachian coal fields, near the West Virginia border. The total leasehold covers more than 33 000 acres. Total annual production at Martin County Coal Corporation is currently 2,500,000 tons, but in certain years exceeded 3,000,000 tons. Approximately 45 percent of the annual production comes from two surface mines. The balance is produced from five underground mines. Martin County Coal Corporation's work schedule consists of 240 days/year, two nine-hours shifts/day.

Jan 1, 1991

By L. A. Arrington-Webb

The International Standards Organization (ISO) 9000 series of quality standards was published in 1987. First initiated by the British in the mid-1970's to assure the quality of British goods and services. ISO 9000 certification demonstrated the capability of a supplier to meet the requirements of the customer. Thiele Kaolin Company has invested considerable time and money achieving and maintaining ISO 9002 certification. Through a regimen of process control and documentation, routine audits, and a commitment to quality management, this kaolin producer continues to be a competitive pigment supplier in a world-wide market.

Jan 1, 1997

By D. Erik Spiller

Introduction The recovery of precious metals from ore can generally be accomplished using either gravity concentration, flotation, and/or hydrometallurgical (leaching) techniques. The objective of this paper is to show why gravity concentration can be an important part of recovery systems which employ leaching as the primary unit operation. A brief discussion of modern gravity concentration equipment is also presented.

Jan 1, 1984

By G. V. Krishna Roa, G. Vijaya Kumar

One of the main objectives while planning ventilation systems for mines with multiple fans is minimization of the total airpower consumption of the mine. Solution of this problem by conventional ventilation network analysis programs is tedious and time consuming, and may not yield optimum results in all the cases. The paper presents an algorithm for solving multiple fan networks by finding optimum combination of fan operating points for required airflow distribution in the ventilation system.

Jan 1, 1995