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By Kal V. S. Sastry, Stephen N. Little

Computer simulation of comminution systems is found to provide significant cost savings by enabling efficient circuit design and development of control systems. These simulation systems are based on sound mathematical models and numerical methods. Nevertheless, they are found to be hard-to-use and hard-to-modify to carry out more elaborate process analysis. This paper discusses the fundamental principles and practical aspects of an advanced, highly functional, and user-friendly SIMulator for COMminution, SIMCOM, that is being developed at Berkeley by incorporating state-of-the-art software engineering principles.

Jan 1, 1992

By Debbie Nakamura, Daniel Tempelis, John E. Shamma

The Metropolitan Water District of Southern California established a Board of Consultants to assist them in administering the design and construction of the Inland Feeder Program tunnels. The Board acts as an expert review body for the owner, looking at key issues that can potentially impact the success of the program. The use of the Board evolved over the life of the project, and its composition was modified to better address the needs of the owner, and the Program requirements. The experience, function, and value of such a board is analyzed and discussed in this paper.

Jan 1, 2003

By W. L. Han, Y. D. Zhang, X. C. Li

Meta-systhetic technique for large systems engineering has been placed on the agenda. The meta-systhetic A1 approach should involve the integration of digital and knowledge info, from qualitative to quantitative analysis, etc. Some algorithms of meta-systhetic technique such as ANN-ES and GA-ANN are introduced. A case study follows - mining conditions evaluation by meta-synthetic A1 methods, including: setting up the structure of evaluation indexes system, deciding their grade of membership by ANN-ES algorithm; determining the weight values of evaluation factors by GA-ANN algorithm; and developing the integrated evaluation model.

Jan 1, 2002

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 Jonathan M. Pachter

Introduction The Bailey mining complex is located in Greene County, PA, in the Talley Run valley. It includes two Pittsburgh No. 8 seam deep mines (Bailey and Bailey No. 2), a coal preparation plant, and two refuse areas. Clean coal is shipped from the complex by way of a 24-km (15-mile) rail spur. It con¬nects to the Monongahela Railroad in Waynesburg, PA. In early 1981, Consolidation Coal Co. (Consol) began a permitting effort aimed at building the mine. Construction began in Dec. 1981, less than six months after the first application submittal. Clean coal was produced by the Bailey preparation plant in Sept. 1984. Several factors allowed quick permitting at Bailey. Effective project planning, including early formulation of a project planning team, and identification of red flag issues helped. So did innovative responses to environmental questions, and development of environmentally sound project designs. Forming a project planning team Consol management decided that Bailey mine construction had to begin in late 1981. A project permitting team was immediately formed to see that this goal was achieved. Team members included a project manager and personnel from Consol's engineering, environmental, and operating departments. Communications among all team members was crucial in obtaining the various state and Federal environmental permits. All project permitting team members participated in weekly meetings during application preparation. Discussions at these meetings ranged from recent public contacts, to application content, to environmental design considerations. Establishing a project manager was critical to the team's success. The project manager was responsible for seeing that permit acquisition, facility construction, and operation of the mining complex proceeded on schedule. The project manager had the final word, mediated disagreements, and frequently served as project spokesman to the public. Identifying red flag issues Red flag issues are those environmental factors with the most potential for delaying the schedule or stopping the project. The first red flag issue identified was organized local opposition. This opposition had completely derailed a US Soil Conservation Service proposal to build a multipurpose dam on Enlow Fork, a short distance

Jan 9, 1985

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 K. N. (Mani) Subramanian

A 2.5 meter diameter column has been successfully used in a 100 tph flotation plant at the Harbour Lights Mine in Leonora, Western Australia, to produce a final gold bearing sulfide concentrate from the ore in a single stage. This pioneering application of column flotation cells to rougher stage was pilot tested using a 11 cm column, which demonstrated column's capability in rougher, scavenger and cleaner flotation stages. A hybrid circuit involving columns and mechanically agitated flotation cell s was adopted for the commercial installation. This paper describes pilot plant results, design of the plant flotation circuit, and early results of commercial operation.

Jan 1, 1988

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 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 Mucella Ersoy, Nese Celebi

Management Information System (MIS), is a system using formalised procedures to provide management with appropriate information to make timely and effective decisions. Before developing MIS, first functions of the organisation should be defined and grouped into subsystems. After determining the information required and produced by each system and interaction between subsystems, the related data resources should be structured into a series of databases and files. In this study, the MIS developed for Soma Open Pit Mines, Turkey is described in this respect. First, analyses of the existing system including user requirements and scope of the system are given. Then the designed information system, its subsystems, interaction between subsystems and system structure are presented in detail.

Jan 1, 2002

By M. G. Ayat, J. W. Leonard

Introduction Coal preparation plants are continuously losing clean coal in their refuse and contaminating their clean coal product with impurities. This is due to the lack of a system by which the immediate efficiency of the cleaning operation can be determined at any given time. Moreover, the advantage of developing tagging/ tracing techniques would be a reduction in the time and money spent in evaluating the performance of advanced cleaning techniques. Currently, conventional sampling and testing, on-line analyses, and computer information systems are the major tools with which engineers analyze and control the efficiency of processing plants. Conventional sampling and testing is an effective analysis technique but it is slow. On-line analysis provides information on quality parameters rapidly, but these parameters do not provide all of the necessary information. The use of tagged particles in coal preparation plants may provide the necessary link between diagnosis and the application of computers to process control. In this work, a novel technique that uses tagged particles to generate partition data is presented (Leonard et al., 1982). Individually prepared tagged particles are added to the feed and detected in the product or refuse port of specific gravity based processes. Providing that a computer can interpret the output of a detection device and trace particles with predetermined physical properties through the coal preparation plant and that the trace particles actually represent desired raw material, sufficient partition data can be provided for computer analyses and control of processing efficiency. Coal tagging technique The use of tagged particles in coal preparation operations are in the early stages of development. Though there is a brief history of particle tracing in the mineral processing industry (Gardner et al., 1986; Foreman and Amundson, 1976; Poston et al., 1962), the concept has not yet been applied to the analysis and control of processing plant operations. Several methods for tagging coal particles have been identified. These include magnetic, radioactive, and fluorescent techniques. As far as the magnetic tagging of coal particles is concerned, a method has been developed to manufacture synthetic magnetic particles of various sizes and specific gravities. Ideally the synthetic particles would have identical size and density as the coal particles being separated.

Jan 1, 1988

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

"On-site research and development as well as in-situ testing are key factors to the successful implementation of new mining equipment and technology. Unfortunately the demands and necessities of research and development often conflict with the reality of mine production in operational mines, especially during early stages of research and development and the initial testing of new equipment. Several experimental mines under university supervision attend to this problem and provide a close-to- reality testing environment for the mining industry and mining equipment manufacturers. This paper gives an overview of the design and organization of such an underground testing area as well as of the wide range of possible operations it can facilitate at the example of the FLB Experimental and Teaching Mine (Forschungs- und Lehrbergwerk) at Technische Universität Bergakademie Freiberg, the central European underground research mine. INTRODUCTION As well as the Mining Engineering education follows the same pattern worldwide, the tasks and duties to be fulfilled by engineers in the productive mines are comparable around the globe. This also holds true for the technologies and equipment needed, both in surface and underground mines. Almost all mining equipment brands are being distributed worldwide. The tasks and challenges of guaranteeing an ever- increasing productivity at the mines, while simultaneously maintaining, respectively improving, safety standards, also in the developing countries and emerging economies, requests a constant development, improvement and adaption both of the engineering education and of R&D in technology and equipment. The increasing safety requirements at the mines, in combination with also increasing safety and liability policies, do often not allow a proper practical education of mining engineering students. At the same time, new technologies and equipment to be deployed / brought to the mines have to be fully functional in a production operation from the very first moment. Time losses like break-down time or even repair and maintenance breaks are often costly and, even when expected up to a certain degree with newly developed machines, have a wider negative impact on the neighboring operations and operations within that mine, thus often being unacceptable within the ongoing production process and extremely costly."

Jan 1, 2015

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 T. W. West

A description of a coal washing spiral is presented, together with a discussion of the parameters which define the envelope within which the spiral can be successfully applied. The correct process engineering, installation, operating and maintenance parameters are addressed as well as actual results for new and retrofit installations on USA coal capital and operating costs of spiral circuits are compared to those of traditional fine coal circuitry.

Jan 1, 1988

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 Michael G. Nelson, Hanguang Wu, V. Izaxon, Sukumar Bandopadhyay

The method of mine ventilation involving heated air, which is frequently used in mines in cold regions, does not correspond to the natural conditions prevailing in permafrost regions; it is not economical and leads to a series of complications which can be prevented or greatly reduced by lowering the temperature of the air stream entering the mine until it is equal to or very close to the temperature of the frozen ground This paper presents ventilation design approaches which can be engineered to provide the required micro-climate and thus en- sure the stability bf the ground for placer mines in permafrost. Specifically three ventilation design approaches are presented: 1) design based on minimum thermal impact; 2) design based on positive/negative heat accumulation in the existing mine airways; and 3) design based on heat exchanging devices such as thermosyphons placed above ground.

Jan 1, 1997

By D. Gu, B. Lin

Discussion of concept Breakage of rock by machine is one of the major methods of excavation. With the development of modern engineering techniques, the advantages of using this method have become even greater. Improving efficiency and reducing the cost of rock breakage is the main goal of mechanizing the rock-breaking operation. For a given stratum, the efficiency of a machine excavation depends, to a large extent, on the design and method of application of the tools used. In a planetary cutter head, the subcutter heads move like planets around the main drive shaft. The general structure of the cutter head is shown in Fig. 1. As shown in this illustration, the main drive shaft (1-1) is connected to the tie bar (1) and, thereby, to a gear (5) that meshes with a fixed-gear ring (2). The subcutter head (4) is rigidly connected to the gear (5) by the subcutter-head axis (2-2). When the main drive shaft (1-1) rotates, the subcutter head (4) rotates around the axis (2-2), under the action of the tie bar and with the help of sleeve pipe (3). At the same time, axis (2-2) also rotates around the main shaft (1-1). As shown in Fig 1, [a] is the angle between the main shaft and the subcutter-head axis. This angle determines the shape of the drilling face. If [a] equals zero, the drilling face will be a flat surface (Fig.1 (a) ), and if [a] is greater than zero, the drilling face will be a spherical surface (Fig. I (b)). For a planetary cutter head, the most important design parameter is the transmission ratio (i), which is defined as [i = (0210)1(1)] Where [(a] is the angular speed of rotation of the subcutter heads around their individual axes, and [o] is the angular speed of rotation of the subcutter-head axes around the main shaft. In Eq. (1), i is positive if the direction of rotation of a subcutter head around its axes is the same as the direction of rotation of the subcutter-head axes around the main shaft (see Fig. 1(b)). Conversely, i is negative when the two directions are opposite (see Fig. 1(a)). When i is positive, the cutters on the subcutter heads form epicycloid paths on the drilling face, as shown in Fig. 2(a). Conversely, if i is negative, the paths will be hypocycloid, as shown in Fig. 2(b). It should be noted

Jan 1, 1996

By J. Patrick Powers, Joel Miller, Arthur B. Corwin

A combination of a slurry trench with dewatering successfully controlled groundwater for a large sloped excavation immediately adjacent to the Arkansas River. The Murray Hydro Electric Project required excavation through sand and gravel to bedrock, 85 feet below high water in the River. The perimeter system of deep wells pumping up to 25,000 GPM (1,600 1/sec) lowered the water level to 15 feet (4.6 m) above bedrock. A short soil/bentonite slurry trench near the toe of the slope cut off the residual head. The method cut six weeks from the critical path. Design of the slopes and the dewatering system demanded high safety factors because of risk to existing Lock and Dam No. 7. A localized pocket of soft organic clay was supported by a rock filled bolster. A major flood event was successfully withstood. The method can be applied to large civil excavations and open pit mines.

Jan 1, 1989

By E. Topuz, M. J. McPherson, I. M. Konduri

Theoretical investigations and laboratory experiments demonstrated that there is a great potential for the use of jet fan ventilation in mines. This paper summarizes research that consisted of laboratory-scale model tests, full-scale mine model tests and underground coal mine entry tests. The laboratory model used water as a fluid medium and simulated a typical 25-m- (82-ft-) long heading having a 1.5 x 6-m (4.9 x 19.7 ft) cross section. The effects of various nozzle positions and designs were investigated by using still photography. It was also found that the use of jets in combination with line curtains enhanced the overall ventilating effect in the model entry. Flow measurements in the full-scale mine model and in the coal mine entry were conducted to evaluate the effectiveness of the jet fan. It was concluded that the designed jet fan ventilation system was an effective means of ventilating blind airways.

Jan 1, 1998