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By J. M. Mutmansky

This paper outlines the results of a study of the opinions of practicing engineers concerning the value of environmental engineering courses in a mining engineering curriculum. One hundred engineers with significant experience in mining-related engineering work were carefully chosen. Of the 67 responses, about half were from mining engineers, and the other half were from environmental engineers. In this paper, the results of the survey are outlined. The number and type of courses recommended by the respondents are summarized as well as the specific topics recommended for inclusion in a mining engineering curriculum. The survey form also asked for the stages in the mine life when environmental experts were needed and the percentage of environmental engineering performed by outside experts for many mining-related environmental tasks. The results of this line of questions are provided. Finally, the paper offers a comparison of the results for environmental engineers and mining engineers and analyzes the differences.

Jan 1, 2003

By R. G. Reddy

Solid state reduction of roast movat chromite ore with carbon was carried out as a function of C/FeO ratio and temperature in the range 800°C to 900°C by thermogravimetry analysis (TGA). A two stage mechanism, (1) the reduction of FeO present in Roast Movat with carbon monoxide; and (2) the regeneration of CO by the oxidation of carbon with CO2 was proposed. The rate controlling step is the carbon oxidation reaction. A kinetic equation, that of random nucleation, was proposed. The activation energy for the reduction was determined to be 55800 J/mole and is compared to those activation energies determined for other chromite ores.

Jan 1, 1998

By R. P. King, M. K. McCarter, K. S. Free

Mine plans typically consider the profits and costs associated with extracting and processing minerals into marketable products. Interrelationships between mine and mill costs are often overlooked during the process of mine plan optimization. A simple and quick method for predicting milling costs for a given block would improve the planning process, especially if the procedure could be incorporated as part of routine ore grade analysis of drill core or cuttings. Incorporating milling costs as part of the mine planning process could improve overall optimization of the mine/mill combination. A method developed by the Utah Comminution Center (UCC) at the University of Utah provides a possible answer to the need for quick and reliable grinding cost estimation (King et al., 1996). Using results from single-particle impact tests, a work index, called the Utah Load Cell Work Index (ULCWI), is calculated. The potential for routine use of the new method is explored by comparing ULCWI values with corresponding Bond Work Index (BWI) values for eight mineral materials (Free, 2000).

Jan 1, 2004

By M. P. Hardy, C. J. H. Brest van Kempen, H. N. Maleki

To evaluate the influence of uniformly tensioned roof bolts on roof stability, mechanically anchored roof bolts were installed using the conventional bolter and a specially developed thrust and torque controlled retrofitable box mounted on a bolting machine. Thirteen thousand bolts were installed over 19 crosscuts in a 4 heading development in an operating coal mine. Geological , bolt and mine parameters were recorded at bolt installation, and bolt tension histories, roof sag and other changes evident in the rooms, crosscuts and intersections were recorded over a 2 month period. In all, 24 variables and 11 responses were quantified at 67 bolt clusters. These data were analyzed statistically to determine the significant variables influencing roof stability. As the mine development was safe and stable during the monitoring period, roof sag after two months was used as an index to quantify "stability." The variables of significance were shown to be coefficient of variation of bolt tension, bolt anchorage capacity, roof lithology, roof shape, standard deviation of bolt tension, and dip of roof lithologies. It was concluded that of the variables with which the mine operator has control, bolt tension uniformity was the most significant parameter at this mine. Other variables, such as intersection type and time between mining and bolting , were not significant, whereas, some other potentially significant variables such as horizontal stress or roof joint frequency did not vary sufficiently for their influence on stability to be evaluated.

Jan 1, 1986

By K. C. Vories

Surface mining and reclamation has the potential to at least temporarily increase surface runoff and resultant erosion and gully development. This increase in erosion is due in part to compaction of the soil surface with heavy equipment, creation of large relatively unvegetated watersheds, and elimination of natural dendritic ephemeral drainage patterns. Methods for stabilizing gully channels which may develop prior to establishment of sufficient vegetation to control erosion are analyzed. Utilization of various sizes of riprap for channel lining, the use of riprap check dams, reinforcement of riprap check dams, and the relation- ship of type of control structure to area of watershed and resultant flow velocities are discussed.

Jan 1, 1986

By J. S. Young

During 1975, the Reclasource Corporation constructed and commissioned a plant for the recovery of mill scale, coke breeze, blast furnace dust, blast furnace sludge and basic oxygen furnace dust at the site of Crucible Alloy Division, Midland, Pennsylvania. The Reclaform Process was employed as the criteria for plant design. This Process takes the solid in-plant fines as listed above, commonly found in integrated steel mills, sizes and forms them through the use of a carbonaceous binder briquetting system and cures the binder through a final heat-treating step. 15,000 tons of Reclaform briquets have been tested in the Crucible blast furnace in several campaigns structured to assess material handling properties, burden feasibility and finally culminating in an iron and carbon assessment campaign. Data are presented from the records of the blast furnace operation and conclusions are drawn that both iron and carbon utilization have been demonstrated.

Jan 1, 1977

By William R. Yernberg

Santa Fe Pacific Gold, headquartered in Albuquerque, NM is expanding its operation at the Twin Creeks Mine in Nevada. The $250-million sulfide expansion project, including the Sage Mill, is under construction and is 80% complete. Also, additional mining equipment has been purchased to haul the sulfide ore to the mill. With the expansion, employment at Twin Creeks is expected to reach approximately 970 people by the end of 1996. Santa Fe Pacific Gold now owns and operates three gold mines in the United States and is involved in several other gold projects. The three currently operating mines are the Twin Creeks, Mesquite and Lone Tree mines. The Mesquite Mine is located in California’s Imperial Valley. Lone Tree is located 55 km (34 miles) southeast of Winnemucca, NV. The company’s total gold production from these operations is expected to be in the range of 26.3 to 26.6 t (845,000 to 855,000 oz) in 1996. This compares to a total production of about 124 kg (4,000 oz) for the company in 1989. Production costs range from $6.90to $7.25/g ($215 to $225/oz). At the end of 1995, the company reported proven and probable reserves of 556.7 t(17.9 million oz) of gold.

Jan 1, 1996

Flotation of dolomite from apatite was investigated, using dodecylamine hydrochloride or sodium oleate as the collector, in the absence and presence of inorganic modifiers such as sodium chloride. Separation of dolomite from apatite was anticipated from the single mineral experiments under various pH and collector concentration conditions. Flotation selectivity in the mixtures, however, was found to be limited. Attempts to control the flotation response of these minerals by addition of salts such as NaCI and KCI indicated that selectivity is possible. The presence of sodium chloride was determined to depress apatite flotation using sodium oleate leaving dolomite flotation unaffected (Moudgil and Ince, 1989). In this paper, conditions for optimum separation and the effect of major parameters on the desired selectivity are discussed.

Jan 1, 1990

By L. Shevenell, L. Stillings

The Acid Drainage Technology Initiative-Metal Mining Sector (ADTI-MMS) has established a Pit Lake Committee to enhance the science and understanding for the long-term management of pit lakes. Participation in this new committee is from members of federal and state agencies, industry, and academia, including numerous individuals representing 10 states. Work has begun on a pit lake literature search and review, database, classification, and sampling and monitoring procedures document. Coordination with the International Network for Acid Prevention (INAP) has been established. Future work will include preparing a prediction and assumption verification document, a report identifying variables upon which water quality is dependent, and an applied remediation technologies document, including an evaluation of the effects of backfilling.

Jan 1, 2002

Ceremonies for the induction of four mining industry pioneers into the National Mining Hall of Fame will be held Saturday, Sept.9, 2006 at the Museum Convention Center in Leadville, CO. The four inductees are Earl H. Beistline (1916 to present), R.A.F. Penrose (1863-1931), Robert M. Reininger (1912-2006) and John Stanton (1830-1906). The inductions will bring to 193 the number of mining “greats” whose engraved photographs and biographical sketches are installed in the National Mining Hall of Fame.

Jan 1, 2006

By F. T. Paleari, J. A. Finch

Radial gas holdup profiles were measured in a 50-cm-diam, 400-cm-high flotation column using a multi-cell-conductivity probe. Three bubble-generation systems, including a system with up to eight vertical filter-cloth spargers, a system with three horizontal filter-cloth spargers and a system with three (horizontal) Cominco-type spargers, were examined. The variables investigated were the number of spargers, the symmetry of their arrangement and the height above the spargers. Batch water containing up to 20 ppm frother was used. Generally, the profiles tended to be uniform (flat) with some profiles exhibiting a slight "wavy" pattern. The vertical sparger arrangement proved to be the most difficult in which to achieve a profile symmetry. The horizontal spargers gave uniform profiles at right angles to their length but gave decreasing gas holdup along their length. The Cominco-type spargers gave slightly less scatter in the data. Switching off selected spargers to simulate a malfunction did not produce strong asymmetry in the profiles.

Jan 1, 1995

By M. Hodgson

The redox reactions that occur on pyrrhotite and pentlandite in contact with oxygenated deionized water were examined using voltammetry. Reactions were put forward in which both minerals were progressively hydroxylated to form thermodynamically metastable surface intermediate products. These intermediates were modelled as metal deficient sulphides where a sulphurous layer was coordinated onto the remaining metal sites via polysulphides. Prior to hydroxylation pentlandite exhibited changes in the surface stoichiometry which were not related to pH effects. The formation of polysuiphide-sulphur intermediates were believed to promote collectorless; flotability for the two minerals. Microflotation tests (0.3 g samples) verified that the surface potential and particle size affected the flotation response, excessive oxidation inhibiting the minerals' flotability. Larger scale tests using ore samples (30 g) confirmed that the extent of pulp oxidation, particle size distribution and the presence of frothers affected the flotation response, the findings being in accordance with the postulated model for the hydrophobic species generated on the pentlandite and pyrrhotite surfaces.

Jan 1, 1985

By B. (Manas) Das

Rock characterization for geotechnical purposes using the microhardness technique is discussed in this paper. The concept of rock characterization and its steps are logically developed. The geotechnical properties should be functionally tethered to the technological problems for characterization. The overriding geotechnical concern is rock mass stability. The important factors in this respect are rock properties, structural discontinuities, ground water, field stress, temperature and technological factors. The rock properties are the primary factors and the other factors generally affect rock properties. Of the rock properties the strength and elastic properties can form a basis for rock characterization. The microhardness technique can provide these two properties. Study on coal shows that the microhardness impressions can be used for this purpose. On the basis of this study coals of all ranks can be divided into distinct geotechnical groups. The details of these are discussed in this paper.

Jan 1, 1986

By Leo Misagi

THE ROLE OF MANAGEMENT IN PLANT SAFETY Safe Production In plant management, safe production is an ideal. It becomes reality when: 1. Plant employees work in healthful and safe conditions. 2. Plant safety is in harmony with productivity. 3. Worker absenteeism and turnover are low-the work force is stable. Plant management must apply its talents, skills, and resources to build and maintain the foundations of safe production on a system of policies, procedures, and attitudes. It must do so by marshaling all managerial functions - staffing, direction, control, innovation, and representation-toward that goal. Ideally, a plant safety program is proactive. Management should plan and implement safety activities that are aimed at prevention. Past accidents-accomplished facts-should not be the sole guide of future actions. In other words, positive preventive measures, not the fewness of accidents are the criteria for safety production. An ideal safety program is one which is cost effective. Management should view plant safety as part of a broader program-loss control. Loss control includes prevention of fires and other accidents, unhealthful conditions, and occurrences that cause bodily injury, illness, property loss, or damage. Management evaluates the employees' productivity and safety. An effective training program aimed at loss control is the hallmark of safe production. Ideally, both labor and management should be well versed in safety. They believe in the premise that work-related injury and illness, as well as property loss and damage from fire and other accidents, are manageable and preventable. Such belief prompts them to learn more about the work process and potential hazards associated with each job. They also learn how to expect and prevent fues and other accidents, and respond to emergencies at the plant. Plant management determines which individuals or groups of employees are accountable for the following functions:

Jan 1, 1991

By J. Stachurski, N. A. Abdel-Khalek

Flotation tests were carried out on six coal samples of different rank as well as their oxidized samples. A mixture of diesel oil and alcohols was used in these tests. Surface oxidation caused a distinct decrease during flotation recovery with some improvement in the grade. The reduction in the recovery increased with increasing concentration of the oxidizing agent. The floatability of low rank coals was affected by oxidation to a higher degree than the floatability of medium and high rank coals. The recovery-size curves of oxidized samples were similar in shape to the recovery-size curves of non-oxidized coals.

Jan 1, 1991

By N. Edmonson

An examination of the statistics of the world phosphate fertilizer industry since 1980 reveals an increasing tendency for fertilizer manufacturing activity to concentrate in phosphate rock mining areas. The economic justification for this resource-oriented strategy is clear. The choice between shipping phosphate rock, a comparatively low-value product, and shipping more valuable finished fertilizers will always be resolved in favor of the latter if cost considerations control the decision. The historical existence of substantial phosphate fertilizer manufacturing capacity oriented toward fertilizer-consuming activities and dependent on imported phosphate rock shows that narrow cost considerations have not always determined the industry's location. One is entitled to ask what conditions have changed to precipitate the observed relocations, and how permanent these changes are. These questions are the subject of this investigation.

Jan 1, 1995

By Hans Svensson

INTRODUCTION The Alimak method of raising (Fig. 1) was intro¬duced in 1957. Because of its flexibility, economy, and speed, it soon became the most used system of raising in the world. With the same unit, raises of various areas, inclinations, and lengths can be driven. Air-motor¬-driven raise climbers normally are used in mines with short raises (Fig. 2). For longer raises electric or diesel-¬hydraulic drives are used. The Alimak raise climber is designed entirely in ac¬cordance with the instructions of the Swedish Board of Industrial Safety (Arbetarskyddsstyrelsen). There are good margins of safety concerning the breaking strength of the material and the raise climber comprises safety devices and features that practically eliminate the risks of accidents. The drive gear of air-driven climbers is equipped with an air-operated brake which is automatically activated when air for the motors is shut off. There is a safety device which activates automatically at overspeed and a speed-regulated brake for descent by gravity, by which the raise climber can be taken down to the bottom of the raise in case of cutoff of the air supply. The raise climber climbs along a pin rack welded to a guide rail which also comprises pipes for air and water. The guide. rail can be extended by using 1- or 2-m (3.2¬or 6.4-ft) sections as the driving progresses. Each guide rail section is bolted to the rock wall by special expan¬sion bolts of Alimak design. Men ride up to the face in the cage, traveling com¬fortably and easily while material is transported on the platform. There is no dangerous climbing up ladders. The men are well protected during ascent and arrive in good condition at the face. The greatest advantages of raise climber systems are flexibility and versatility. The equipment provides a comfortable working position in vertical as well as in¬clined raises of any area and length. The direction may

Jan 1, 1982

By John G. Holmes

The generation of low cost power is but one phase of the TVA program for regional development. During the 36 years since TVA began, growth in its generation of electric power has necessitated a shift from a predominantly hydroelectric power system to a combination steam and hydroelectric system. The addition of steam-electric power plants to TVA's generating system was necessitated by the rapid increase in the traditional and defense demands for electric power in the 80,000-square-mile area served by TVA, the need to firm up the hydroelectric power, and the fact that all available sites for sizeable hydroelectric projects had been developed. At present TVA owns and operates 40 power plants--29 hydroelectric and 11 steam-electric plants. The total generating capacity of the hydroelectric plants is 3,105,430 kw, and the capacity of the steam plants is 13,951,135 kw. This provides a total generating capacity of 17,056,565 kw for the plants operated by TVA. Individual capacity of the 112 hydroelectric units ranges from 10,000 to 67,500 kw, and the individual capacity of the steam-electric units now in operation ranges from 60,000 to 950,000 kw. In addition to this generating capacity, TVA distributes the power from 6 U. S. Army Corps of Engineers hydroelectric plants on the Cumberland River. These plants contribute an additional 725,000 kw. Also, under an agreement with the Aluminum Company of America, TVA directs the stream flows and generation of their 423,715-kw system on Tennessee River tributaries and shares with Alcoa in the increased generation resulting from this coordinated operation.

Jan 1, 1969

By E. Peuraniemi, S. Strömberg, S. Jyrkönen, A. Jokilaakso

Several sulfidic raw materials have been flash oxidized in a laboratory furnace in oxidizing atmospheres at temperatures of 500-1100°C. Chemical analysis was used to determine the oxidation degree, and optical and scanning electron microscopy combined with energy dispersive analysis were used for characterization of the reacted particles. The studied materials included both Cu and Ni concentrates and mattes. In fixed conditions, the temperature dependence of sulphur removal rate was found to be equal for all the copper concentrates studied. Nickel concentrates and Cu- and Ni-mattes were, however, found to be less reactive. Most of the particles were found to spheroidize and to fragment to small droplets under intensively oxidizing conditions. The product particles were frequently found to be iron oxide cenospheres or dense spheres with a composition of mixed Cu-(Ni-)Fe oxides.

Jan 1, 1998

By J. W. Motter

Currently, virtually all new electric power generation systems under construction are designed with natural gas as the primary fuel. Factors driving these construction decisions involve sustained low prices for natural gas, environ-mental (and consequent regulatory) risks associated with the use of coal for power generation, and relatively high costs of construction for conventional coal-fired power plants. Despite the unarguable abundance of coal in the US. and worldwide, a fundamental question arises: What will be the role of coal in electric power generation in the 21st century? Congress, recognizing the vital and strategic importance of preserving the coal option for electric power generation, authorized the Clean Coal Technology Program. This pro-gram, with original funding in excess of $2,500 million, is intended to promote the demonstration and commercialization of a new generation of clean, efficient coal-based energy technologies through collaboration and partnering with private industry. The two technologies being demonstrated under this program which are the key to the continued use of this nation's huge coal reserves are coal gasification and the pressurized fluid bed. Either or both of these technologies, coupled with a combined cycle will pro-vide the continuing future coal option, while responding to increasingly more restrictive environmental standards. Recent Congressional budget-cutting efforts, however, could threaten the effectiveness of that model program, and ultimately other subsequent government-industry collaboration.

Jan 1, 1996