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By Richard M. Tinlin

Some of the practices of the mining industry that may place an undesirable stress on the groundwater environment are coming under increasing scrutiny from legislators and regulatory agencies. Among these practices are mine dewatering, the use of tailings ponds, land rehabilitation, and technological innovations such as in situ leaching of waste clumps and ore deposits. Pernichele, noting that 24 states have enacted legislation controlling to varying degrees the environmental effects of mining, has emphasized the importance of assessing the potential for damage to groundwater when evaluating, planning, and designing mining projects. 1 Illinois has enacted legislation requiring anyone opening, operating or abandoning a mine site to obtain a permit from the Illinois EPA. The law is one of the first to require regular monitoring and reporting to a control agency. Legislation has also been recently enacted at the national level that will have a significant impact on the mining industry; e. g., the Federal Water Pollution Control Act Amendments of 1972 (Public Law 92-500). The stated objective of this Act is to restore and maintain the chemical, physical and biological integrity of the nation's waters. Specifically, according to Sec. 102(a), the Administrator of the U.S. Environmental Protection Agency (EPA) is required to prepare or develop comprehensive programs for preventing, reducing or eliminating the pollution of the navigable waters and groundwaters and improving the sanitary condition of surface and underground waters. The definition of the terms "pollution" and "pollutant" is of particular significance to those who must comply with PL 92-500. The definitions are quite broad and include most of the adverse water quality effects of man's activities. As defined in Sec. 502(19), "pollution means the man-made or man-induced alteration of the chemical, physical, biological and radiological integrity of water." Within the Act, the list of pollutants includes dredged spoil, solid waste, incineration residue, chemical wastes, radioaetive materials, heat, wrecked or discarded equipment, rock, sand, cellar dirt, and industrial waste discharged into water.

Jan 1, 1973

By V. F. Hollister

Although it is apparent that porphyry copper deposits may have formed in the Andean orogen from Permian time onward, commercial deposits thus far developed appear to have Cenozoic ages only. Following Chilean useage, the porphyry deposits are divided into either: (a) a stockwork, or (b) a tourmaline breccia model. Stockwork type deposits tend to occur on major strike-slip structures which may be either transcurrent or transverse faults related to plate movements, while the tourmaline breccia type may more frequently form independently of regional faults. Stockwork types may be conjugate fractures that intersect and ramify as a network of veins and veinlets, cutting altered rock, and genetically related to a major regional fault, or in other cases they may reflect the intersection of two large fault structures. Circular fracture patterns may more rarely occur in stockwork deposits in response to a specific intrusive. Tourmaline breccia types are characterized by circular and radial fractures genetically connected in some way with tourmaline breccia pipe development or an intrusive piercement that preceded it. Each structural model contains mineralized intrusive8 which have a close time-space relationship to ore and in each model, mineral paragenesis is similar, regardless of age or location in the plate. Also, each model contains the same type of alterntion halos (phyllic, argillic, prophllitic) as are developed in intru- sive centers in porphyry copper deposits found in North America. The potassic zone is exposed best in the older deposits. Examples of each type of deposit are illustrated, demonstrating the feature evolved.

Jan 1, 1973

By T. I. Martinovic

A major investigative' program was conducted on the development of an acceptable substitute organic binder for bentonite for the pelletizing of the Iron Ore Company of Canada's Carol concentrate. The first phase of the program covered an evaluation of several organic binders in laboratory tire balling in order to identify the most promising potential organic binders. Based on the green ball quality obtained, Peridur C-10, Alchem 8C26 and peat moss were selected for full scale pot-grate testwork. The selected binders were tested with various pelletizing mixes (acid, dolomite, limestone and fully fluxed). The pot-grate test results showed that an acceptable pellet quality can be produced with the use of Peridur C-10.

Jan 1, 1989

By Edgar T. Gregory

A quiet revolution has taken place in the conveyor belt industry, Man-made materials, improved production facilities, better splicing techniques and emphasis on repair and maintenance have all contributed substantially to lowering material handling costs for the mining industry, It wasn't too many years ago that the rubber industry had only cotton for a belt carcass and tree grown rubber for the protective cover. Then came the development of monofilament rayon. This material had desirable elongation and elastic properties and was the first synthetic fiber to be used in place of cotton. But wet strength and other limitations restricted its use, and the conveyor belt industry turned to nylon. Initially, nylon was considered suitable only for the cross threads or filler threads of a belt carcass. Then technical advancements in heat setting and fabric weave created a major change in belt construction. As a result of these advances the industry was able to take advantage of the full tension strength of nylon cord. Another breakthrough in the use of synthetics was the tremendous increase in adhesion resulting from a chemical bond, rather than the limited physical bond available with cotton. But the advantages of nylon had a more Car-reaching effect, We were able to design a two-ply nylon belt that did the work of a four- or five-ply cotton or rayon belt. A six-ply nylon belt now replaces a twelve-ply cotton elevator belt. Arid nylon resists moisture, acid and mildew, It also has excellent resistance to impact and can be produced with controlled elongation and elastic properties that work to great advantage in reduced-ply belt constructions.

Jan 1, 1971

By R. Kealey, D. Huo, Q. Zhang, Y. A. Sari

Greenhouse gas (GHG) emissions from primary mineral and metal production account for ~10% of global GHG emissions. One of the main sources of GHG emissions in mining operations is fuel consumption by haul trucks. Given their size and carrying capacity, the fuel consumption of haul trucks can approach 250 liters per hour. An average of 30% of the idle time of the trucks is spent while waiting in the queue. Inefficient truck dispatch planning can waste resources, cause dilution and elevate GHG emissions. In this research, a machine learning based truck dispatch approach was developed to dynamically route the haul trucks based on the loaded material, the road traffic, the estimated wait time, and the maintenance needs of the trucks. The GHG reduction potential of this smart fleet management approach was estimated by calculating and comparing the related carbon emissions versus scenarios using traditional fleet allocation approaches. Results suggest that this dynamic fleet allocation approach can significantly reduce GHG emissions at mineral production sites by optimizing waiting times and the overall distance travelled while achieving the same production levels.

Mar 2, 2022

By V. Svalbonas

Presently the U.S. mining industry is very conscious of costs. It is timely, therefore, to review the dominant specifications used in the industry for procuring large size-reduction equipment. These are compared with other specifications and procurement methods, such as ASME and DOD, using the criteria of resulting costs, safety/ quality, and fitness-for-service.

Jan 1, 1987

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

A paradigm shift As market economists, mine managers are interested in "staying in business" and even "prospering." Bottom-line results are the "order of the day." Concern for bottom-line results can invoke questions such as how much was produced, at what cost, and was anyone injured? While these questions will always carry everyday emphasis at the mine, they are fundamentally lacking in that they often appear, especially to lower levels of management and to the production worker, as pre-eminent concerns. Driven by market economics, many organizations have decentralized, outsourced, downsized, restructured and formed new coalitions. Investments in new technology and a concentration on productivity have been an essential part of these changes, contributing to improvements in both safety and efficiency. A reason for (and, perhaps a result of) these improvements has been the development of a highly experienced and flexible work force. This situation presents an interesting opportunity to modify a few paradigms about work life in general, and perhaps a few paradigms about how we invest in the miner, in particular. Studying these issues now night offer some interesting opportunities for the Future, as the foundations for the next generation of mine workers are laid. With the average "experienced" U.S. miner five to fifteen years from retirement, perhaps a key determinant of future success in the world market might be how well we make the transition from today's work force to the work force of tomorrow. We can ill afford to wait a few more years to tap into the special knowledge residing within a veteran mining work Force. The Work Crew Performance Model (WCPM) is one approach to defining, capturing and transferring this expertise. The WCPM suggests a paradigm shift, moving from a focus on products (quantity) to a focus on the process (quality). It also involves a slight change in the process -- a different way to think and work. Of great importance, it entails a belief and a commitment to people within the organization; a commitment to collect simple (but interesting) data; exploration for insightful ways to plot and integrate that data; and finally the search for creative methods to reinvest that knowledge back into the organization, that is, back into the work force. As a way of thinking, the WCPM subordinates information about how much is produced daily or how many were injured over a year's time to concern and detail for how the individual's and the work crew's performance contribute toward meeting organizational goals. Drawing upon the expertise within members of that work crew to address and solve operational problems is one approach for meeting organizational goals. This everyday focus on how we work is hypothesized by the WCPM to make the difference between a good section supervisor and the average one; an exemplar continuous-miner operator and the run-of-the-mill one; a mining crew that produces consistently high quantities, but, inadvertently, degrades the production of other units. The WCPM permits objective and reliable performance data to be collected. This data then can be used to define variability within tasks of work crew members; to relate observed variability to a cost consequence; and to more meaningfully analyze performance through the integration of traditional analytical tools, such as the production simulator, CONSIM, with a recommended behavioral approach, the WCPM. Basis for engineering test Most equipment selections and purchases involve a field trial test of the system. Technology is routinely bench tested at the manufacturer's facility, government agencies and the mine site. The WCPM suggests a similar, but more practical, method for testing the performance of a work system -a test for how technology is used (by people) at the work site. It implies learning from veteran mining personnel that have gone well "beyond the book." This approach to learning and to integrating training with everyday work life can help answer questions such as: What constitutes desirable perfor¬mance as, for examples, a shuttle-car operator, a miner operator or a bulldozer operator; what characterizes exem¬plary performance within the context of the work system, the technology and the work crew; how can investments in the worker he linked to measurable results within the organiza¬tion? This paper explores these questions and makes recom¬mendations for enhancing the cost-linkages between invest¬ments in people and the mine's monthly cost sheets.

Jan 1, 1996

By I. J. Lin

We have studied the possibility to use electrical phenomena in order to selectively separate minerals with various densities and dielectric constants in non-homogeneous electric fields. This technique is based on levitation forces acting on a solid particle immersed in dielectric fluid. When the gradient of the electric field is directed downwards, the levitation force in the dielectric fluid (pure liquid or electric colloids) will be in an upward direction to float sinking minerals by counterbalancing their density mismatch with the liquid medium. The separation process can be made by using two possible modes: either by direct application of electrical forces or by change in the density and dielectric constant of a liquid medium in which the mineral particles are placed. We have investigated several electrode configurations in order to produce electrical fields which are strongly non homogeneous. Further more, investigation on the dielectric properties of liquids have been performed.

Jan 1, 1977

By James L. Evers

The development of hydraulic mining in the United States has had an uneven record of progress. The shifting of coal extraction from one government agency to another has not provided an environment for a focused national research program. This paper presents an update on hydraulic mining research in the United States. A comparison is made between the development of the technology in this country and the state of the art in other parts of the world.

Jan 1, 1983

Column flotation cells continue to gain acceptance in the coal industry for the treatment of high-ash streams containing clay slimes. Unfortunately, some industrial installations have failed to meet expectations due to improper scale-up, incorrect operation and poor ancillary circuit design. To overcome these problems, case studies have been conducted to fully define the capabilities of column cells for coal applications. These data have been used to develop generic engineering guidelines for column circuit design and operation. An economic analysis has also been conducted to illustrate the importance of key capital cost considerations. These analyses indicate that column cells are significantly more expensive than conventional machines, although this difference can be greatly reduced through the installation of very large-diameter columns.

Jan 1, 1999

By B. Yarar

The critical surface tension of wetting (?c) of Cu2S, FeS2, PbS, and MoS2 were determined by plotting flotation recovery versus YLV which was arranged by methanol, and Extra-polating to % R = 0. ?c values ranged from 26 dyne cm-1 for MoS2 to 49 dyne cm-1 for PbS and elemental sulfur gave a value of 31.5 dyne cm-1. Minerals exhibiting natural flotability of different extents, could be separated from their mixtures in the absence of conventional flotation reagents, but controlled ?LV. Correlations between non-stoichiometry and degree of natural hydrophobicity for MOS2 are also reported in this paper.

Jan 1, 1983

Copper cathode and Uranium Oxide production at WMC (Olympic Dam Corporation) Pty. Ltd. involves processing leach liquors through a copper solvent extraction plant followed by a uranium solvent extraction plant. This paper discusses the processing problems, metallurgical testwork and circuit changes made due to contamination of amine in the oxime circuit and vice versa.

Jan 1, 1996

By R. L. Grayson

Following lip on a USBM-sponsored research project, the authors have utilized the knowledge-base structure and system concepts from the 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, their availability on a shift, and work priorities for a shift as well as to allocate manpower optimally on a work shift and delineate supervisory training responsibilities. The various components of the software are described in detail, along with enhancements made to the original system.

Jan 1, 1996

By Paul Chamberlin

Although performing a heap leach test is inherently simple, a lot of information beyond extraction, leach time, and reagent consumption can be obtained from a well designed test program. The following is a list of information to look for and acquire when performing column tests and field heap leach tests.

Jan 1, 1998

By Eugene L. Foster

The engineering profession has traditionally devoted its efforts to understanding and modifying the Earth's environment in order to adapt it to man's needs. In appraising our overall performance, I would have to say it has been a mixed bag. In many areas, notably communications taken in the broadest sense, and development of creature comforts, we have done a good job. In others, we have failed, particularly in our assessment of the effect of our work on the environment. Our failures have been due in part to a lack of understanding or foresight, and in part to a disproportionate emphasis on lowest first cost. Now, with an increasingly large number of people living in a finite environment, there is an urgent need for reassessment. It is no longer possible to pursue a single objective without regard to its side effects. Our projects are too large, and there are too many of them. Environmental impacts must be taken into account in all important engineering decisions of the future. There are forces at work which will help to bring this about. Thinking people everywhere have realized that adverse alteration of our environment eventually affects every one of us. The majority of our citizens, who now live in cities, are beginning to appreciate the advantages of a good natural environment in a way which others who have been closer to the soil have appreciated for years. Our people have flocked to the cities because they wanted to be "where the action is." At the same time, there is a strong desire for what we have come to call the quality of life. Today, we all want the standard creature comforts. We want to be able to move freely

Jan 1, 1974

Two key strategies for a new generation of mining are developing domestic raw material production and doing so in an environmentally responsible way, according to presenters at the 83rd annual meeting of the SME Minnesota Section in Duluth (the 71st annual University of Minnesota Mining Symposium). From technical sessions detailing how to build com-munity support, to a short course on international perspectives in iron ore mining and processing, the two-day meeting emphasized the potential of Minnesota state deposits and the importance of maintaining productive community relations both locally and globally. The meeting of more than 300 mining industry professionals began on April 20 with a traditional convocation celebrating the values of northern Minnesota. The accompanying tradeshow, with a record 131 booths, showed the speed and vigor of the economic rebound. Keynote speaker Scott Anderson, vice president and senior economist at Wells Fargo, stated the prevailing mood of the conference: ?Wow, what a difference a year makes.? With metal prices and sales up and heading higher, he said, it was clear that the production-centered economic recovery is reaching the mining and the minerals industry. However, Anderson sounded a few notes of caution. Serious threats to economic stability remain, including the burgeoning national de?cit, high unemployment and the still out-of-control foreclosure crisis. Overall, he predicted a below-average recovery and stressed the importance of developing a long-term business strategy.

Jul 1, 2010

By S. C. Torma

Sources of lead contaminated soils are numerous, i.e., the uses of leaded gasoline, lead-based paints, leaded pesticides, solders, smelting of lead concentrates, refining of lead products, automobile demolition, recycling of lead batteries, and so on. Conservative estimation by the US Environmental Protection Agency, EPA, indicated that several thousand lead contaminated sites are awaiting remediation. The current remediation technologies include immobilization, reclamation and soil washing. In this paper, the above remediation technologies will be reviewed, and where appropriate, the economics of processes discussed and future possibilities indicated.

Jan 1, 1996

By Douglas M. Deason

Swelling clays, such as montmorillonite, contribute significantly to the poor dewatering and consolidation behavior of the Florida phosphate clay wastes. Understanding and to a degree, control of the forces which cause the swelling behavior may aid in supplying a solution to this problem. The technical feasibility of utilizing control- led dispersion for aiding dewatering of phosphatic slimes was investigated. This technique is based upon inhibition of swelling and self-dispersing tendencies of the montmorillonite clays by dispersing the solids in electrolyte solutions. Through this process, significant improvements in settling rates and sediment solids content were achieved in both pure clay systems and on simulated phosphate slimes.

Jan 1, 1983

By W. G. Prast

The role of governments as a factor in the international non-metallic minerals industry can take several forms. Classically, the government acts as a taxing agent, collecting part of the economic rent on behalf of the country from private-sector mine operators. In addition to its taxation policies, the state can and does provide the practical commercial framework of regulatory and fiscal incentives and restraints that shape the activities of the mining firms. In addition to its functions as an agent of the public interest, the government can choose to take a more direct stake in the mining industry, and has done so in the instance of several industrial minerals that are actively traded on world markets. In this paper, the actions of three governments are reviewed and the consequences of their actions are examined.

Jan 1, 1981

By James T. Tanner

Mica is a generic term that applies to a group of complex aluminosilicate minerals that have a sheet or plate-like structure and with different chemical compositions and physical properties. All micas form flat six-sided monoclinic crystals with remarkable cleavage parallel to the direction of the large surfaces, which permits them to be split into optically flat films; as thin as 1µm in thickness in some cases (Rajgarhia, 1987). Some micas are more easily split than others. For example, muscovite mica found in pegmatites is more easily split into thin films than is phlogopite. Mica found in mica schist is not as easily delaminated as mica found in weathered pegmatites. According to Dawson (1 949), the commercially important mica minerals are: Muscovite-potassium mica (colorless to pale green and ruby) Biotite-magnesium-iron mica (dark brown to black) Phlogopite-magnesium mica (pale yellow to dark brown) Vermiculite-hydrated biotite or magnesium-iron-mica (bronze yellow flakes) Lepidolite-potassium-lithium mica (pale lilac to deep purple) Some micas of less importance are: Zinnwaldite-lithium-iron mica (gray to smoky brown) Roscoelite-vanadium-potassium-magnesium mica (various shades of green and brown) Mica, principally muscovite, is widely used for industrial applications because of its exceptional physical, chemical, electrical, thermal, and mechanical properties (Table 1). Phlogopite and vermiculite follow muscovite in importance. Biotite finds very little commercial application at the present time. Commercially, mica is used in a number of forms. These forms and their description follow: Sheet mica refers to books of mica either mined from hard rock (pegmatites) or from loosely consolidated clayey material formed from the weathering of pegmatites and alaskites. These books can be readily split into thin film or splittings with specific thicknesses ranging from 0.0031 to 0.10 mm (Davis, 1985). Quality sheet mica is graded into 10 quality classifications (Tables 2 and 3). Books of mica that are flawed with excess inclusions, cracks, or folds (A mica) are called scrap mica and are either ground into commercial products by a dry or wet process. Built-up mica was developed in 1894 as a result of the cost and scarcity of sheet mica, and because many satisfactory electrical parts could be made from it (Preston, 1971). This type mica is formed by layering pieces of mica splittings upon one another and binding them together with inorganic or organic binders. These sheets are then pressed together under high temperature. Mica for this process is produced from pieces of sheet mica too small to be punched into electrical parts (Davis, 1985). Reconstituted mica is mica paper produced by forming a mat of very thin delaminated flakes of scrap mica. This mat is usually impregnated with an organic binder, but is also available unimpregnated. It is dried at 110°C. The mica for this process is either produced from the trimmings of a sheet mica operation or from blocks of A type mica (Davis, 1985, Chapman, 1983). Ground mica constitutes by far the largest use of mica, both quantitatively and application wise. It is produced by grinding and sizing scrap mica (also mica concentrate) obtained from five sources, 1) trimming from sheet mica, 2) A type mica blocks, 3) as a byproduct of spodumene and feldspar mining, 4) weathered pegmatites and alaskites, and 5) metamorphic schists. Synthetic mica is produced by crystal growth in a slowly cooled melt of accurately proportioned chemical oxides. Extended cooling times at a specific viscosity result in larger crystals. Many different micas have been formed by this process; however, fluorophlogopite is the most common.

Jan 1, 1994