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By Lane White

In conjunction with its 1993 Annual Meeting, held Feb. 15-18 in Reno, NV, SME sponsored a symposium, "Conveyor Belt Engineering for the Coal and Mineral Mining Industries." Eighteen papers were presented, grouped into four sessions: Low Tension Drives, High Tension Drives. Novel Techniques and Specifications. Three of the papers have been republished in this issue of MINING ENGINEERING. Brief summaries of the other 15 papers are presented here. (The 193-page symposium Proceedings, edited by Mike Evans of Consol, includes all of these 18 papers and is available from SME. For the convience of interested readers, an order form is included at the end of this Proceedings summary.)

Jan 1, 1993

By R. A. Speirer, T. C. Bettinger, L. P. Richardson

INTRODUCTION The Bureau of Mines (The Bureau) remote sensing researchers at the Denver (CO) Research Center, have been investigating computerized methods to detect and map surface linear features called "lineaments" for ground hazard assessment in mines. Many of these lineaments at the test mine site were found to correlate to subsurface geologic discontinuities such as faults, fractures, and joints that intersect coal seams at depth. These features adverse1 y affect the roof and rib integrity in underground mines, thus contributing to rock failures that may result in injuries to mine workers and loss of production. Advance knowledge of the existence of such hazardous geologic features can aid in mine planning and development. Lineaments may be observed in a variety of images of the earth's surface. Linear features that can be observed using Landsat mu1ti spectral scanner data (MSS) images range from regional (greater than 3 miles in length) to an intermediate length of from 1 to 3 miles. These images are recorded in discrete radiation bands in the green, red, and near-infrared portions of the el ectromaynetic spectrum. These data are acquired from the EROS Data Center of the U.S Geological Survey, Sioux Falls, SD, in digital format on magnetic tapes that are suitable for processing on certain minicomputers. Shorter lineaments length (less than 1 mile) can be observed in high- to low-a1titude aerial photography, radar, and infrared images with image scale ratios of 1:1,000,000 or less. These linear features can correlate to smaller dimensioned faults, and to fracture and joint sets at the local geologic scale. Other informational sources can help substantiate 1ineament analyses, such as well logs, mine naps, topographic data, and geophysical data acquired over the study site. These data must be in a digital format to process on the "DEC PDP 11/23 minicomputer system1". Data can be acquired in

Jan 1, 1986

By J. W. Rold

In 1973 housing and construction conflicts threatened Front Range gravel resources. The legislature addressed the problem by passing HB 1529, which required the Colorado Geological Survey to map the deposits and forbid local governments to change lands over commercial mineral deposits from zones allowing mineral development to zoning which conflicted with development. It charged counties to develop Master Plans for Extraction. Plans must consider resource quality, multiple-sequential-use potential, surrounding area compatibility, neighbors, quality of Life, extraction maximization and reclamation potential. Imprecisely worded statutes, budgetary constraints, lack of enforcement and political pressures have limited benefits from the law.

Jan 1, 1987

By Robin J. Batterham, Dave J. Robinson

The most significant trend in flotation has been the ever-increasing scale of operations. There is, however, doubt that this ongoing trend is enough to maintain the economics against trends such as falling grades, increasing mining costs, pressure on water supply and demand, rising energy demands needed for mineral processing, and a focus on whole of life value and mine legacy issues. We comment on the ramifications of broader uptake of more sustainable mining for mineral processing methods and address the specific question of whether recent progress in in-place recovery will lead to a timely breakthrough. The answer proposed is that this is possible in the next 10 to 20 years, but in the meantime the focus is just as likely to be on removal of waste (beneficiation) much earlier in circuits. Either way, mineral processing and flotation as we know it will change significantly. 

By R. T. Webber, D. Moffett, D. W. Averill, G. H. Kassakhian

INTRODUCTION In Canada, radium-226 is removed from uranium mining and milling effluents by the addition of barium chloride to precipitate barium-radium sulphate. Large settling ponds are provided to effect solid-liquid separation. However, the barium-radium sulphate precipitate [(Ba,Ra)S04] is a fine, slow-settling crystalline solid which is not easily removed by simple sedimentation systems. Consequently, settling pond effluents may contain appreciable quantities of particulate or suspended radium-226, depending upon the specific pond system and/or the time of year considered. Also, current technology is expected to be incompatible with ultimate disposal goals since safe recovery of the barium-radium sulphate sludge from the settling ponds may be difficult to achieve (IAEA, 1976). Under the auspices of Environment Canada, a Government-Industry Mining Task Force established a Radioactivity Sub-Group in 1974 to assist in the development of effluent regulations and guidelines for the uranium mining industry. Among the recommendations of the Sub-Group was the need to seek more effective methods of radium removal, including development of physical--chemical treatment systems as an alternative to settling ponds. In response to the Sub-Group recommendations, a bench scale feasibility study began in March 1976 at the Wastewater Technology Centre (WTC) of Environment Canada. The bench scale work was expanded and accelerated in 1977 with financial assistance provided by the Atomic Energy Control Board. The results of this study indicated that coagulation and flocculation of the (Ba,Ra)S04 precipitate greatly increased settling rates (Wilkinson and Cohen, 1977). Subsequently, a research program with a larger scope was initiated in January 1978; this program is jointly managed and funded by government and industry as indicated in Table 1. The principal goal of the Joint Government-Industry Program is the development of a physical-chemical process to reduce the radium-226 content of uranium mining and milling effluents. The following effluent radium-226 activities were established as targets for the program: 0.37 Bq/L (10 pCi/L) as total radium-226; 0.11 Bq/L (3 pCi/L) as dissolved radium-226. Process development work was undertaken at bench scale at the WTC and at

Jan 1, 1980

By A. B. Samaddar

A prototype automated mapping and spatial information management system has been developed, and illustrates how a powerful map manipulation capability and a comprehensive display system can be combined using both raster and vector mapping: The concept of a mapbase and information retrieval mechanism, query language as well as text and graphical menus, is introduced. The Geographic Information System (GIS), which has been built around a system for storage and retrieval of spatial and textual data, allows interaction with geographic space represented on a displayed map. The prototype is demonstrated using maps and information of an open pit mine.

Jan 1, 1989

By G. Granger, D. Malhotra

The paper briefly reviews the criteria employed in the selection of chemical reagents for testing and discusses the steps involved in laboratory and plant evaluation of these reagents. An example of successful implementation of reagent change in the plant is illustrated.

Jan 1, 1986

By Kenneth V. Luza

Underclays are associated with coals found in eastern Oklahoma. These coals are of bituminous rank and are in beds of Middle and Late Pennsylvanian age. They occur in an area of about 8,000 mi2, within the southern part of the Western Interior Coal Region. The rocks of the area consist of a thick series of sandstones, shales, underclays, coals, and limestones. There are more than 40 beds of bituminous coal in the state, but only 12 of these have been mined over large areas. The 12 are, from oldest to youngest: the lower Hartshorne, upper Hartshorne, McAlester (Stigler), upper McAlester, Cavanal, Rowe, Secor, Weir-Pittsburg, Mineral, Croweburg, Iron Post, and Dawson coals. None of the underclay associated with these coal beds is known to have been exploited commercially. Nine samples of underclay from beneath the Croweburg coal were collected over a wide area in the eastern Oklahoma coal field for evaluation. The underclays are usually shades of gray with brown or orange iron-oxide staining. Although soft and plastic in some places, they are generally hard and slickensided, and contain abundant carbonized plant fragments. Bulk chemical analyses, clay mineral identification, and ceramic tests were performed on each underclay sample. The dominant clay minerals are illite and kaolinite with some mixed-layer clays. Silica (Si02) ranges from 45.96% to 59.03% and alumina (Al2O3) varies from 14.98% to 23.60%. The U.S. Bureau of Mines Tuscaloosa Re- search Center conducted the ceramic evaluations. Samples were slow fired from 1,000°C to 1,250°C in 50°C intervals. Bulk density, color, percent linear shrinkage, and percent absorption were determined for each slow fire test. All Croweburg underclay samples are best suited for building brick.

Jan 1, 1999

By Gurses Oner

In situ leaching is a relatively old mineral extraction method; however, historically only a small portion of copper has been produced from small scale operations. Recently, in situ leaching technology because of its intrinsic advantages over conventional mining and milling is being considered as a viable option for recovering copper from both low grade oxide and sulfide deposits. This paper presents the application of computers to investigate in situ technology using large whole core leaching experiments. Computers were applied to three different areas: (1) experimental control and data acquisition, (2) non-destructive evaluation of samples using x-ray computed tomography and image processing and (3) mathematical modelling and data analysis.

Jan 1, 1992

By D. D. Misra

The paper presents a computer simulation package developed for the size¬-reduction circuits of Indian hematitic iron ores. The package is developed by linking independent procedures describing different unit operations like crushing, screening, recycling, etc. Mathematical models are used to quantify the unit operations involved. The models are selected after thorough analytical studies of the samples and data collected from four operating plants. The package developed gives a fairly accurate result with respect to, size and chemical composition of the flow stream and products. The program written in PASCAL can be used to try the flowsheet with various raw ores, as well as different flowsheets with the same raw ore.

Jan 1, 1989

By P. K. Davis, B. Gharib

The results of a previous basic study of the flow and design characteristics of hydrocyclones demonstrated that a recovery as high as 99% with a product rating* of 0.95 can be achieved on a batch+ basis with a single, water-only cyclone if it is configured properly. The next logical step was to demonstrate continuous processing of gob for the efficient recovery of coal by means of a laboratory-size demonstration system. A project to design and construct such a single-¬cyclone system was sponsored by the US Department of Energy, which also sponsored the initial study. A recovery of 93% with a product rating of 0.89 was demonstrated. The system design and the data taken are discussed.

Jan 1, 1990

By Stephen R. Brown

The principles of quality management are well developed and, from a practical stand- point, thoroughly implemented in the process industries of Japan. Although these principles are now applied to the U.S. manufacturing industry, and as a result, the steel industry, they have been largely ignored in the non-ferrous and precious metals industries. This paper presents the concepts and practical approaches to implement a total quality management program. Contrary to the beliefs of many managers, such a program increases yields, recoveries and output while it decreases unit costs. In fact, quality management incorporating statistical process control will be an essential ingredient for metallurgical plants to effectively compete in the '90's.

Jan 1, 1991

By H. Suharyono, M. Lutsky, R. Hogg

Sediment consolidation in highly flocculated suspensions occurs only if the self-weight of the material exceeds its compressive yield stress. A simple model for sediment densification is presented and applied to the simulation of thickener operations. Measured relationships between sediment self-weight and the extent of consolidation are used to establish underflow densities. Supernatant turbidity data provide the information necessary to predict overflow clarity. It is shown that thickener depth can play a role in determining solids-handling capacity as well as dewatering performance. The application of the model to the design and operation of full-scale thickeners is described.

Jan 1, 1995

By E. S. Smith, Sunirmal Banerjee

INTRODUCTION Social awareness of the detrimental impact of man-made wastes on our environment has grown considerably during the last two decades. Increased public and institutional concerns have resulted in the implementation of a wide variety of regulatory controls of disposal of wastes. These regulations have often reflected significant conservatism in expecting guaranteed elimination of pollution risks. This sort of expectation assumed a state of knowledge which was not readily available to the major producers of wastes. The mining industry, in particular, has been affected by such regulations in terms of excessive costs and loss of benefit. As a result, investigations are in progress (1) to generate newer methods for satisfactory stabilization of mine and mill wastes and (2) to apply the available technology to achieve the standards set by the regulatory agencies at reasonable costs. This paper presents a conceptual scheme for stabilization of mill wastes by suitable management of operations and accelerated consolidation of tailings slurries. The main discussion in this paper is aimed at the ability of the proposed scheme to address the major considerations in effective disposal. Comparison in both cost and effectiveness are also made between the proposed scheme and various other currently used disposal concepts. MAJOR CONSIDERATIONS IN EFFECTIVE DISPOSAL The primary objective of an effective tailings disposal scheme is to provide containment of the contaminants in such a manner that the undesirable impact of the wastes on the three basic elements of our environment--land, air, and water-would be minimal. Bearing the above objective in mind, one may justifiably list the major considerations in the choice of the disposal scheme in terms of its effects on land, air, and water (Bromwell, 1976) as follows: Effects on Land (1) whether the scheme makes optimal use of land.

Jan 1, 1980

By Edward M. Belsky

Increasingly stringent government environmental regulations will affect the availability and costs of bonding and insurance products for the mining community. New regulations requiring Environmental Impairment Insurance, Reclamation Bonds, and Cyanide Use Bonds will result in both an increase in cost and a decrease in availability of affordable insurance and bonding pro- ducts. Professional Liability Insurance for engineers that covers pollution exposures will be a must for all professional engineers working in the mining community. By understanding the problem, solutions can be structured to allow your company to obtain the mandated insurance at the most favorable cost and conditions!

Jan 1, 1991

By R. J. Sweigard

Many states are considering the need to establish or modify policy relating to the disposal of coal ash. One of the primary concerns is the impact of leachate from the ash disposal sites upon groundwater and nearby bodies of surface water. A detailed site investigation was conducted at a coal ash disposal facility associated with a power generation station. The disposal site is situated alongside a major river. Monitoring wells were installed and soil samples were taken for characterization. Groundwater models were used to simulate migration of leachate from the disposal site toward the river. Such models have the potential to be used to verify regulatory compliance. This paper addresses the validation and adaptability of these models to this case and their usefulness as possible tools to be used in future environmental audits.

Jan 1, 1993

By J. C. Emerick

Preliminary investigations have shown that wetland-based treatment systems can be an effective and relatively inexpensive control strategy for mine drainage pollution in eastern coal mining regions. This strategy also has potential for western mining regions, although too few systems have been installed in the west to permit general evaluation of the concept for western climates. The construction of prototype systems is encouraged for some situations. Wet-land environments have the capability of removing metals by natural geochemical and biological processes, including precipitation, filtration, ion absorption, and biological uptake and accumulation. Data presented for natural wetlands receiving mine drainage show removal of iron and other metals, and high accumulation of metals in soils and plants.

Jan 1, 1988

By P. C. O. Chukabarah

Atkinson's resistance square law is the cornerstone equation for traditional expression of energy losses in mine ventilation engineering. But the nomenclature for the various forms of energy losses are often confused for one another, misapplied or misinterpreted. These forms of energy were re-examined from thermodynamic and fluid-dynamic perspectives. Resultant expressions showed that both incompressible and compressible flow regimes in underground mines can easily be accommodated. Given the well-known three major energy forms, which are equivalent to one another but numerically unequal, corresponding equations to Atkinson's (pressure loss) for headloss and workloss were derived. The thermodynamic weight relational resistance ([w] s2/m5) associated with energy per unit weight (headloss) was dimensionalized for the first time. Also, normalized Atkinson-like equations for headlosses and worklosses were derived to ease direct computations in mine ventilation practice.

Jan 1, 1995

By R. L. Wolfrom, R. Hogg, S. Chander

A gravimetric method for measuring rates of capillary rise in powders was explored. Methods to improve reproducibility and consistency of the results were investigated. In particular, the effects of particle size and packing uniformity were addressed. Studies of the wetting behavior of both spherical glass beads and irregularly shaped synthetic graphite particles by various organic liquids were carried out. Standardized procedures for bed preparation will be described. The applicability of the Washburn equation for surface energy evaluation in such systems will be discussed. Key words: Wettability, Powders, Capillary rise, Surface chemistry

Jan 1, 2003

By F. Grandjacques

INTRODUCTION Selective Reduction of Nickel in Oxidized Ores Oxidized nickel ores, either garnieritic or lateritic, contain much more iron than nickel. The regular carbon reduction in an electric furnace is operated in such a manner that the greater part of iron oxides is reduced simultaneously with nickel oxide, resulting in a low nickel content ferronickel. In order that the nickel content of residual slag may be suitably low, -excess carbon must be fed so that the carbon content of the ferronickel thus obtained is that of casting iron. The metal also contains other impurities such as silicon, chrome, etc. In order to convert the casting iron into slightly carburized ferronickel with high nickel content, the greater part of the carbon and more than half the iron contained therein must be oxidized by means of oxygen. Energy is thus consumed as carbon, and power to reduce iron oxides, and more energy is consumed as oxygen to re-oxidize the iron contained. This method can be economically adopted for nickel ores with grades ranging around 2. 5 to 370, but it gets excessively costly when nickel grade falls below these values. This is why, for nickel ores with low nickel grades and high iron content, studies were conducted to develop a selective reduction process which, while reducing only a small part of the iron oxide, would provide efficient reduction of nickel oxide. Rich ferronickel is thereby obtained, with nickel content ranging around 30 to 50%. Due to the presence of slag with a high iron oxide content, the metal thus

Jan 1, 1979