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By K. Lapakko

One responsibility of the Minnesota Department of Natural Resources is to encourage the development of mineral resources within the state. A second responsibility is to ensure that mineral development does not adversely impact other natural resources, including the water resources of the state. One approach the Division of Minerals has taken to fulfill these responsibilities is to conduct cooperative research with the mining industry. To encourage mineral development the Division has cooperated with industry on projects related to exploration, mining, and mineral processing. To examine environmental issues the Division has worked in concert with iron ore, base metal, and precious metal exploration and mining companies, as well as the Western Governors' Association, US Bureau of Mines, US Bureau of Land Management, and the US EPA for the past 20 years. These projects were conducted to evaluate methods of predicting, preventing, controlling, and treating problematic mine waste drainages, as well as mine waste revegetation. This paper I) briefly summarizes cooperative projects conducted, 2) enumerates elements which have contributed to the success of cooperative projects, and 3) describes changes implemented for future projects at the Division's new field and laboratory research facilities, as well as at existing mine and plant sites.

Jan 1, 1998

By James W. Evans

It appears that all extractive processes involve, at one or more points, fluids (gases or liquids) and that the flow of the fluid is an essential part of the functioning of the process. Usually that flow is turbulent and the turbulent flow frequently determines the rates of mass and heat transfer as well as other important phenomena such as bubble/droplet breakup and coalescence, particle suspension, etc. Over the past decade many attempts have been made to model turbulent flows in metallurgical unit operations. The present paper summarizes some of that work. Amongst the operations considered are agitated leaching, ladle metallurgy, electrowinning/refin- ing, induction furnaces, Hall cells and electro- magnetic casting. Where possible, comparisons are made between model predictions and experimental results.

Jan 1, 1990

By Chester R. Harris

With the passage of the Occupational Safety and Health Act (OSHA) on December 29, 1970 and the formation and growth of the OSHA Agency it spawned, public consciousness of occupational safety was raised. It became accepted that employees had the right to "a safe and healthful workplace". With the possibility of OSHA inspections, employ ers (particularly those with large workforces) began to give serious con sideration to engineering controls, safety programs, and training in a more uniform manner than previously.

Jan 1, 1991

By Joseph L. Condon

The U.S. Department of the Interior, Bureau of Mines, is doing research on methods to obtain premining information on problems such as detection of old mine workings, abandoned oil wells, channel sands, faults, and other geologic features that are undesirable from a production or safety aspect. Techniques being developed to acquire the necessary information include seismic and electromagnetic. The seismic methods include high-resolution seismic and acoustic methods applied from the surface and inseam channel waves applied under- ground. The electromagnetic, or radar, methods are applied from the surface, from boreholes, and from the working face underground. All of these methods are useful under certain site-specific conditions, but none of these methods is universally applicable for all mining conditions.

Jan 1, 1980

By Yoginder P. Chugh, K. V. K. Prasad, R. Missavage

This paper presents results of field monitoring and finite element studies to analyze and improve a room-and-pillar retreat mining system. Fie1 d instrumentation was utilized to monitor pi11ar load changes, roof to floor convergence and differential roof strata movement as retreat mining progressed and to determine in-situ horizontal stresses. A two-dimensional finite element model depicting strata behavior at this mine was developed and used to analyze existing and alternate improved mining geometries. The results showed excellent correlation between fie1 d observed and model predicted behavior. Some of the recommended changes in mining geometry based on the study were incorporated in the mining system.

Jan 1, 1986

By A. Covelli, A. B. Cecala

Two recent US Bureau of Mines studies evaluated workers' dust exposures in automated pallet loading processes. The first study involved a Bureau designed dust control system using a push-pull ventilation technique. The unit was shown to reduce workers' dust exposures by 76% during pallet loading at a ground silica operation. A hydraulic lift table was used to automate the bag stacking process. This kept the loading height constant throughout the entire pallet loading cycle. The second study evaluated different commercial, automated-pallet loading systems. These systems automatically stack the bags onto pallets, shrink wrap the pallets, and deliver the pallets to a fork lift pickup location. Results from a ground silica evaluation site indicated respirable dust samples taken were below the Threshold Limit Value (TLV) as established by the Mine Safety and Health Administration (MSHA).

Jan 1, 1992

By Robert J. Clarke

Reflections on over ten years experience handling bituminous coal from railroad cars to ground storage and lake vessels. The arrangement of the facilities is described but the basic theme of the discussion is the experience gained and lessons learned from facility operation. The Great Lakes provide the maritime environment for the economical transport of vast quantities of raw materials from their source in the Upper Lakes (the Mesabi Range, for instance) to Lower Lake Ports. Lake Erie, because of its proximity to the steel centers , blossomed with the great ports that now line its southern shore - Toledo, Sandusky, Lorain, Cleveland, Huron, Ashtabula, Conneaut and Erie.

Jan 1, 1981

During foundry sand reclamation process development, molds formed from reclaimed chromite sand showed a rapid decline in tensile strength during thermal cycling tests. Because this characteristic could limit reuse of chromite sand in the foundry, the sand was examined in detail. Scanning electron microscopy, x-ray mapping, magnetic susceptibility, and x-ray diffraction were utilized to evaluate processed chromite sand. It was found that process variables such as binder composition, reclamation temperature, and processing method had a significant effect on the chromite sand particle surface. X-ray diffraction indicated a crystallographic change in the processed sands. Magnetic susceptibility also increased after processing. Diffusion of iron to the particle surface and increased surface roughness were identified as potential causes of the decreased tensile strength in the molds.

Jan 1, 1993

By Dennis C. Drehmel

Because of their relatively low cost, carbonate rocks are desirable in abatement of air pollution by acid gases. Although many processes and types of equipment have been proposed to control or prevent the emission of acid gases, this paper considers only three: dry-limestone injection, wet-limestone scrubbing, and chemically active fluid beds. For the dry-limestone-injection process, surface area-especially from pores in the 0. 2- to 0.3-micron range-is one of the important parameters which will discriminate between less and more reactive carbonate rocks. Marls, chalks, oolitic calcites, and other fine- grained limestones show larger-than-average surface areas and better- than-average removal efficiencies. Inert chemical impurities such as silica detract from reactivity. A dolomite is not necessarily less re- active than a calcite. For the wet-limestone-scrubbing process, dissolution rate of the carbonate rock controls the differences in stone reactivity. In this process the dolomites are less reactive than the calcites. In addition, more than 90 percent of the dolomitic impurity in Fredonia white lime- stone is inert during limestone scrubbing. Dissolution rate is also a function of particle size for large-grained carbonate rocks. Fine grinding of such rocks will increase the dissolution rate to that of a fine-grained rock. Hence the requirement of high dissolution rates may be met by some grinding of fine-grained material (e. g., marl, chalk, or other limestone) or by fine grinding of coarser grained material. For chemically active fluid beds, chalks have the best capacity to absorb both SO2 and H2S. However, most chalks are probably unsuitable for fluid beds because of high attrition rates. Because dolomites are generally more reactive than calcites with both SO2 and H2S, a dolomite would be the feed material of choice for a chemically active fluid bed.

Jan 1, 1974

By Surendra K. Mishra

The increasing volume of wastes being generated by industry is a legacy of the industrial revolution and subsequent industrial growth. Social and regulatory pressures have been mounting on industry to improve its waste management practices. In many industrial sectors, waste disposal has been the only method of waste management. Land farming, underground burial, deep wells and incineration are still practiced. Often, concentration and volume reduction of waste streams are also practiced to reduce the waste management costs. In the recent years, there has been emphasis on waste minimization. Since the 19th century, industry has practiced recycling of usable resources as a way of handling unwanted byproducts. The mining industry has recovered or extracted economic minerals from tailings for decades. For example, during the gold rush period of 1970s, extraction of gold from tailings dams became economically attractive. Similarly, when it was economical, coal and shale fractions have also been recovered from tailings and refuge materials for commercial uses. In the steel industry, with the development of new furnace technology, recycling of flue dust and scrap iron was practiced as early as in the 19th century. Before 1900, there was little incentive for the industry to reduce the waste volumes. Manufacturers, however, did see a rationale for adopting profit-increasing techniques. They made an effort to recover and recycle economic materials from waste sources. One of the pioneering examples of resource recovery is the coke making industry. As the industry was market driven, products recycled from coke batteries included ammonia for use in fertilizers, gas for power generation and heating, and tar for road construction, wood preservation and roofing. Tar had been avery troublesome waste byproduct. But it quickly became a valuable chemical raw material, providing the foundation for Germany's dominance of the world's dye and medicine markets before World War I. Similar trends evolved in the chemical industry. In the context of current environmental regulations and escalating mining and processing costs, recycling of re- [ ] sources is becoming economically more attractive. Solid and liquid wastes generated by industries contain a range of inorganic and organic contaminants. Among these contaminants, metals and hydrocarbons form major groups. Treatment of these wastes is essential to meet regulatory disposal requirements. In the recent years, based on the principles of chemical and mineral process engineering, processes have been developed to treat these industrial wastes. This article reviews some of the processes that have made impacts and have proven to be effective at commercial scales.

Jan 1, 1999

By E. B. Graves

I have been asked to talk to you this morning about phosphate marketing and distribution. In discussing this I will attempt to answer such questions as: What is phosphate? Where do we get it? What form is it and how do we sell it? How do we distribute it? How is it applied? And last, but not least, What about the future? To start with, phosphate is one of the three primary plant nutrients. It is the element essential for root structure of plants. Plants, like humans, need a balanced diet. Thus, the amount of phosphate required by individual plants is, in part, related to how much of the other nutrients are used. Virtually all soils contain a certain amount of available phosphates. Back at the turn of the century the most common source of additional plant nutrient, including phosphates, was from cattle manure. The use of chemical fertilizers is something that has grown significantly during the last half century, and in particular, the last 20 years.

Jan 1, 1977

By N. Oswald

As coal mines age and become more developed, ventilation modeling becomes more important for the planning and continued operation of the system. Numerous studies have been performed and presented that address the collection of data and measurement of airway friction factor and resistance per unit length values. However, a quantitative analysis of the resistance for stoppings in coal mines for different construction materials and methodologies has not been adequately addressed. In order to develop an accurate/realistic ventilation model both airway resistances and stopping resistance values need to be determined. Over the course of the past two decades Mine Ventilation Services, Inc (MVS) has measured the resistance of stoppings of various construction types in mines throughout the world. An analysis of this data is presented in this paper along with a discussion of measurement methodology.

Jan 1, 2009

By J. E. Garlanger, R. K. Shrestha

During mining, the surficial aquifer and, in some cases, the top of the uppermost confining unit within the mined areas are excavated. Portions are removed from the area for resource recovery. Until the mined areas are reclaimed, the surrounding unmined area continues to dewater. The impact of mining and subsequent restoration of the surficial aquifer on the ground and surface water resources of the watershed affected by the mining will be described. This will be done in terms of ground water recharge, ground water levels, and base flow and runoff to surface streams. Data from actual mining situations will be used in analyses and discussion. Recommendations will be made for further research.

Jan 1, 1992

By J. Kelleher, R. Saulters, K. H. McDaniel, L. Griswold

To improve underground safety and visibility during mining applications, the Waste Isolation Pilot Plant designed and built a dry-dust filtration unit. The unit works in conjunction with a Spendrup 1120-70 fan with ventilation tubing to filter the face exhaust air during mining operations. The closed- loop system is designed to filter 17 m3/s (36,000 cfm) and is intended to screen 10- µm (1,250 mesh) and larger particles at 90% efficiency. To accomplish this, the unit uses a combination of Dollinger Staynew Inertial Spin filters, cyclones and traditional mesh filter media.

Jan 1, 2002

Conventional wisdom in the mineral processing industry leads one to believe that pressure oxidation of refractory carbonaceous (preg-robbing) ores is not a practical approach to process development. Initial acid pressure oxidation testing on carbonaceous sulfide ores at the Twin Creeks Mine supported this conventional wisdom. After testing other refractory process options, including air and oxygen enriched roasting, Santa Fe Pacific Gold decided to take a second look at pressure oxidation, using conditions outside the normal range of conventional practice. A combination of very fine grinding and high operating temperature and pressure resulted in significant increases in gold extraction. This paper details the effect of operating parameters developed for Twin Creeks on gold recovery, sulfur oxidation, carbon oxidation/passivation and preg-robb through the laboratory and pilot plant investigations.

Jan 1, 1995

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 J. P. Golightly

The structure and occurrence of nickeliferous laterite profiles are described and explained in terms of mineral solubility and drainage conditions. Complete profiles, from top to bottom, include: limonite zone; nontronite or silica zone; and saprolite zone. The middle zone is present only where drainage is sufficiently slow to allow saturation conditions to build up with resulting quartz or smectite precipitation. This precipitation may occur in any climate at a water table or in tropical climates with a long dry season. The degree of serpentinization of the laterite parent rock is important in determining the nature of the saprolite zone. Unserpentinized peridotite produces saprolite ores with hard residual rock cores, nontronitic or amorphous saprolitic rims, and fracture fillings of garnierite and quartz. Ser-pentinites yield relatively homogeneous serpentine saprolite, with minimal quartz or garnierite.

Jan 1, 1979

By D. DeGagné, E. De Souza, J. F. Archibald

A comprehensive survey of minefill practices in underground mines in Canada has been conducted. The survey was designed to cover the entire filling operation for individual mines from feed to the preparation plant, to underground transportation, and to stope placement. The questionnaire examined such areas as mining method utilized, the purpose of backfilling, backfill formulations, including binding and chemical additives, slurry properties, transportation parameters, stope preparation procedures, backfill placement properties, fill instrumentation, and costs. This paper presents the current state of backfill usage in Canada, identifies trends in minefill practices and provides mine operators with an updated database to compare their own practices with modern trends throughout the industry.

Jan 1, 2001

By T. Kelly

The Cannon Mine is located in Chelan County, near Wenatchee, Washington, at the eastern foot of the Cascade Mountains. The mine is situated about two miles from the Columbia River, in the arid Columbia River Valley. Two hydroelectric dams provide electricity for the area, the Burlington Northern Railroad has a switch yard and loading facilities in Wenatchee. Approximately 25,000 people live in the area. The principal industry is fruit farming. Underground mining techniques are used to provide feed for a 2,000 tpd flotation concentrator at the site. The techniques are low- cost, high productivity methods which allow for a high extraction rate along with a high rate of recovery of the minable reserve.

Jan 1, 1986

By A. C. Barlow

The use of deep wells for waste disposal is not a new technique. The production phase of the oil industry has been using this method to dispose of unwanted oil field brine since the 1930's The adoption of this method by other branches of industry, however, to dispose of manufactured wastes is a relatively new development, but one which is finding increased use (2). Deep well waste disposal is not an ordinary technique even though it is finding relatively wide application. In fact, just the opposite is true; it is still a rather extraordinary measure. It is not now, nor is it ever likely to be a disposal method which can be assured of success before it is tried.

Jan 1, 1964