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By Prasannarao Dontula, Kal V. S. Sastry

Advances are made in the field of mineral processing on a continuing basis both in the industry and the academia. These advances do not always get used fully because of the inherent difficulties in the transfer of knowledge and reduction to practice. In recent years, knowledge engineering is being increasingly employed in other fields to overcome some of these difficulties. This paper presents a vision of how knowledge engineering can be applied to the benefit of the mineral processing industry and includes a discussion of associated principles, techniques, and advantages.

Jan 1, 1993

By Tom C. Palanglo, Norbert Maerz

Control of crushing and grinding circuits ideally requires continuous particle size measurements on both in- and outgoing streams. Until recently, size distributions could only be obtained by screening methods, which were neither cost effective, frequent enough, nor timely. Input streams are often composed of large fragments, making screening prohibitive. Optical image processing systems, such as the WipFrag System, have been developed to the point that they are an extremely valuable tool to characterize, control, and fine-tune the comminution process. Although accuracy is less than that of screening, measurements are precise enough to detect relatively small changes in size distributions.

Jan 1, 2000

By R. Candia

The use of industrial wastes, such as quarry fines of crushed stone, should represent a basic component of sustainable development indicators. Therefore, increasing investments should be foreseen in techniques of treatment and recycling of residues in mining, as well as by-product attainment that generate jobs and income. The standards of identification and discarding of industrial wastes vary significantly between countries. However, practically all nations have started becoming more restrictive regarding environmental legislation, especially concerning production, transport, treatment, recycling and final discarding of industrial wastes. Under an environmental point of view, solid wastes produced by a system (such as a quarry) can be handled in two ways: a) they can be discarded in piles or b) they can be internally or externally recycled and reused. This second practice is translated to an additional economic consequence such as an increase of income as well as a decreased environmental impact. This option is more advanced and should be included in company policy. This paper presents cases where this practice is used, i.e. diminishing the environmental liabilities through the use of the quarry fines in the manufacture of industrial devices, incorporating such wastes in the productive chain, instead of storing them in piles.

Jan 1, 2007

By Alfred G. Hoyl

The small miner and small mine have an important role to play in the finding, developing and production of our mineral resources. "Help, not hinder" must be our byword. We must push in every way we can devise to change the adversary position of government and environmental movements. We need the small mines and they must be encouraged, not hindered. Technically excellent and adequate equipment is available, and needed information is also available to the small operation. Environmental questions and problems must be fully considered regardless of the size of a mining operation.

Jan 1, 1987

By Erland A. Tillman

The U.S. National Committee on Tunneling Technology under the aegis of the National Academy of Sciences has long recognized that productivity in major underground construction projects could be increased through better contracting practices and better management. Between 1974 and 1978, this Committee has prepared three reports on these subjects. This paper reviews these reports and their recommendations. It covers the extensive actions by the U.S. National Committee on Tunneling Technology to bring the recommendations to the attention of leaders in the underground construction industry and thus further their adoption and implementation. These activities are continuing. Visibility in this session will give these reports and recommendations increased exposure.

Jan 1, 1981

By A. Afrouz, F. P. Hassani

The types of bulkhead that contain backfill in stopes under various pressures and mining conditions are outlined. Conventionally adopted theoretical and empirical techniques were integrated in the design and construction of each type of bulkhead utilized underground. Methods to monitor the performance of bulkheads are discussed.

Jan 1, 1993

By Y. Akin, M. S. Celik, T. Batar, F. Arslan

Despite its importance in various diverse industries, research on beneficiation strategies of boron minerals has not received enough attention. Boron minerals are primarily upgraded by wet processing methods. However, severe environmental constrains have accelerated the development of dry processing techniques such as calcination. Interestingly, the boron minerals colemanite, ulexite and borax undergo decrepitation, shrinkage and expansion, respectively, upon heat treatment. Each mineral then requires a different beneficiation scheme. In this study, laboratory and pilot-plant studies conducted in our laboratories on the calcination of boron minerals are briefly reviewed and their implications to commercial operations are discussed.

Jan 1, 1999

By Werner Stahl, Karsten Keller

Vibration screens are commonly used not only in classifying bulk material but also in dewatering it. The lack of a comprehensive physical theory of dewatering often leads to difficulties in the design and operation of the vibration screens. Firstly, the dewatering of bulk material will be shown, based on a physical model. Because of the oscillatory motion of the liquid in the bulk, the inertial force of the accelerated liquid and the dripping of water out of the bulk or screen must be taken into special consideration. The physical model put forward shows the effect of the various operations parameters of dewatering screens. The comparison between dewatering theory and practice will be shown by measurements using coal, limestone, etc. Dewatering measurements, which have been conducted on a vibration screen, demonstrate that different vibration frequencies and rates of acceleration lead to different residual moistures. Finally, the possibilities of improving vibration dewatering will be described.

Jan 1, 1995

By Gary Buchan

During several months in 1996 and 1997, Cyprus Twentymile Coal Co. (TCC) set world production records at its Twentymile Mine in northwestern Colorado. These records were due to the company's implementation of a state-of-the-art longwall mining and conveyance system along with a -highly dedicated work force. This article is a case study of the design of long panels at the mine from conception to implementation. Obstacles that needed to be overcome included subsidence engineering, environmental regulations, conveyance, ventilation, equipment design and continuous miner (CM) development timing.

Jan 1, 1998

By Ahmet Unal

Inexpensive and effective means of delivering courses to mining engineers who live at remote and scattered locations remains to be a challenging issue. Computer-based instructorless but interactive multimedia delivery is a good substitute to traditional short courses and one-way broadcasts. Such a system, enhanced with a wide area network, is an inexpensive alternative to two-way broadcasts and even to a traditional university. Course material can either be delivered on compact disks (CDs) or on-line from the host servers over the phone lines using a personal computer and a modem. Although technically not feasible using ordinary telephone service lines at the present time without further modification, advances in this field indicate that this up and coming medium may dominate the competition in the future. This paper investigates the present and the future of this technology and discusses the experiences gained in creating and disseminating a prototype multimedia CD which was created at the Rock Mechanics and Explosives Research Institute of the University of Missouri-Rolla to teach a portion of a course in Ground Control. The hardware and software used in creating the audio, 3-0 graphics, animation dips, video clips, and movies are listed. The structure of the program and the way how interactivity was achieved is explained in detail.

Jan 1, 1996

By K. Hanumantha Rao, K. S. E. Forssberg, A. Vidyadhar

Using pure albite and quartz minerals, the separation of albite from quartz using mixed cationic/anionic reagent schemes is assessed through Hallimond flotation, zeta potential and diffuse reflectance FTIR studies. The reagent schemes are tested in bench-scale flotation for the separation of albite from Greek Stefania feldspar ore. The single mineral flotation tests showed the feasibility of selective albite flotation from quartz at around pH 2 using a mixture of cationic diamine and anionic sulfonate collectors or a combined cationic-anionic collector of diamine-dioleate. In contrast to the selective flotation response of albite at pH 2, where albite is slightly negatively charged and quartz possess zero charge, the zeta potential and FTIR studies elucidate similar adsorption behavior of mixed collectors on both of the minerals. The infrared spectra not only showed the co-adsorption of anionic sulfonate or oleate with diamine on the surface but also showed that the diamine adsorption increases with the presence of anionic collector. The intrusion of anionic collector in between adjacent surface alkyl ammonium ions decreases electrostatic head-head repulsion, thereby increasing the diamine adsorption by increasing the hydrophobic tail-tail bonds. The discrepancy in the flotation and adsorption results at pH 2 is attributed to the coarse and fine size particles employed in these studies, respectively. The comparable adsorption on fine particles of albite and quartz at pH 2 is explained by the interaction of ammonium ions on silanol groups by hydrogen bonding besides electrostatic interactions. The bench-scale flotation results indeed showed that selective albite flotation takes place only after desliming the feed material. An albite concentrate exceeding 10% (by weight) Na20 is produced from a material containing about 6.5% (by weight) Na20, where an albite product of more than 9% (by weight) Na20 is considered to be valuable. Key words: Flotation, Adsorption, Zeta-potential, FTIR

Jan 1, 2003

By Paul D. Dupree

Introduction Trapper mine is a dip-line strip coal mine, located about 10 km (6 miles) southwest of Craig, CO. The mine provides the Craig Generating Station, operated by Colorado-Ute, with about 2 Mt (2.3 million st) of coal annually. The Trapper mine is situated on a hillside that climbs in elevation from 2 to 2.5 km (6500 to 7400 ft) at average grade of 15%. The coal seams dip at about 16% down-grade and they outcrop near the top of the hillside. They exceed maximum stripping depth in 1 to 1.7 km (3500 to 5500 ft) of pit length. Stripping in the three existing pits is performed with three Page 752 23 m3 (30 cu yd) walking draglines. Two of the pits are currently being cast blasted. Until the active cut, the Derringer pit was cast blasted only where the lower mined seam exceeded stripping capabilities and the pit was a single seam operation. Now, a 9-m (30-ft) interburden bench has been incorporated into the stripping plan. This bench protects the first seam of coal from shear when the overburden is cast blasted. The cast blasted section of the 1.6 km (53,000 ft) long pit has been increased from the 457 m (1500 ft) casted previ¬ously to 1 km (3500 ft). High speed films show the coal losses due to shear of the blast are minimal. The pit width in Derringer pit is 61 m (200 ft). This is necessary for efficient spoil side stripping of a relatively thin interburden in the two-seam section of the pit. The Enfield pit is entirely cast blasted. The single seam pit is 46 m (150 ft) wide, 1.1 km (3600 ft) long, and varies from 15 and 46 m (50 and 150 ft) in overburden depth. The overburden strata at the mine consists of medium-hard layers of sandstone, shale, and

Jan 1, 1987

By John S. Egbert

Many of you are familiar with the Washington Metro Project. However, inasmuch as some may not be, and others may want to refresh their memories regarding certain facets of the project, I will cite a few summary details about the rail transit system we are constructing. That summary will also give each of us a common point for departure as I develop the principal thoughts that I want to leave with you. The Washington Metropolitan Area Transit Authority (WMATA) is an interstate agency established by Compact between the District of Columbia, Maryland and Virginia and approved by the United States Congress. Currently, the Authority has approval to build and operate a 101-mile (162.5 km) regional rapid rail transit system as shown on Appendix A. Of that total, 38 miles (61.2 km) will be in D. C., 32 miles (51.5 km) in Maryland and 30 miles (48.3 km) in Virginia. (Mileage figures, because of rounding error, do not add to 101 miles.) Referring again to the 101-mile total, 48 miles (77.2 km) will be underground, 42 miles (67.6 km) on the surface and 10 miles (16.1 km) on aerial structures. Of the 48 miles (77.2 km) that are underground, 15 miles (24.1 km) are rock tunnel, 14 miles (22.5 km) are earth tunnel, 0.5 miles (0.8 km) 9.s sunken tube and 19 miles (30.6 inn) are cut-and-cover construction. The system will include 86 stations, with 51 of them underground. Referring again to the full 86 stations, 43 will be in D. C., 23 in Maryland and 20 in Virginia. We currently have 37 miles (59.5 km) of line and 41 stations in operations as shown on Appendix B. Also shown on Appendix B is another 16 mile (25.7 km) increment and 13 stations which have been substantially completed, but are not yet in service. Additionally,

Jan 1, 1981

By AMIR EHSAN KIANFAR, Moritz Ziegler, TOBIAS HARTMANN, ELISABETH CLAUSEN

Accurate positioning information is a central step in the process of increasing automation and digitalization in the mining industry. Underground mine environments are prime examples for GNSS-denied environments that pose several additional challenges for the employed indoor positioning system (IPS). This work presents an ultra-wideband (UWB)- based system specifically tailored for underground mine environments. Initially, the UWB technology is reviewed and basic concepts of IPS are explained. Both software and hardware are described in detail, including positioning algorithms, electrical circuitry and the mining-compatible enclosure. Finally, the results from field tests in an underground mine are presented and positioning performance and the influence of dilution of precision (DOP) on positioning results are empirically evaluated. The results show that the localization errors are mostly below 1 m. Individual zones of high localization errors are suspected to be caused by noise interference. Significant DOP influence due to the mining drift geometry can be confirmed. The system shows promising localization results for different mining applications, while influences negatively impacting the accuracy are presented as items for future research.

Jan 1, 2024

By V. P. Keran, K. Leung

Two 32 foot x 14% foot, 6.4 MW autogenous mills have been installed in the Mount Isa Mines Copper Concentrator to replace the fine crushing plant, fine ore bin, rod mills and primary ball mills. This paper describes the reasons for the change, the rationale for the new circuit design and configuration, the design and scale-up processes used to size the mills, considerations for the installation of large mills inside an operating concentrator and some early operating data.

Jan 1, 1992

By John C. Schneider

During the past decade, operators and researchers have worked toward a better understanding of the mechanisms operating in flotation. As reported by W. J. Trahar in 1981, this work commenced with the operators determining a relationship between recovery and particle size. They defined three particle size ranges, that being fine, intermediate and coarse. It was noted that the fine and the coarse ranges had slower flotation rates than the intermediate range as demonstrated by their lower recoveries.

Jan 1, 1998

By John G. Banker, Arthur L. Forrest

Titanium solves corrosion, maintenance and environmental problems in many reactor and autoclave applications. Titanium clad construction permits autoclave designers a great deal of flexibility combined with significant cost reduction. Titanium alloys can be selectively applied in specific regions of the auto­clave to accommodate local environmental conditions. Resistance to general corrosion, crevice corrosion, abrasion, and ignition conditions can be accomplished selectively and eco­nomically. Explosion clad pressure vessel fabrication and perfor­mance have been proven through three decades of experience.

Jan 1, 1996

By Priscilla P. Nelson, Yousof Abd Al-Jalil, Christopher Laughton

Prediction of excavation rates is a critical element in the pre-planning of a tunnel boring machine (TBM) project. A realistic evaluation of performance expectations is needed that reflects both the knowns and unknowns of the excavation process and geologic conditions. Current planning procedures are often based on deterministic “best guess” estimations. In this paper, a probabilistic approach to performance simulation is presented that will permit rational consideration of general and project-specific uncertainties in establishing realistic performance estimates. Companion to the simulation software is a database of over 600 public-domain case histories.

Jan 1, 1999

By Joseph F. Peters

The paper will begin with the physical parameters of design in a wire saw. These will include such things as the type of wire used, abrasives, horsepower of operation, and drive components. It will then go into the many uses of wire sawing in the quarrying and finishing of granite. This will include a step by step program of the removal of a block unit of granite from the quarry site through the finished slabbing and jointing in the plant. After this, there will be a small insertion of possibilities of wire sawing techniques in underground excavation work. This would be speculative only. I will use the example of powerhouse type of excavation work given to me by Dr. John Reed, and try to explain how I would attack this type of work using wire saws. Several slides of both design criteria and actual installations were shown.

Jan 1, 1997

By Michael G. Strominger, Anthony E. Gross

The development of precious metals ore agglomeration with a cement binder, by the U.S. Bureau of Mines, has allowed the economical heap leaching of low grade gold ores (<0,05 oz/ton) over the last decade, Even with the Bureau of Mines technology, numerous operations continue to experience channeling and blinding problems. A research project was undertaken at Nalco Chemical to address situations where improved agglomeration is needed, By increasing the incorporation of fines into the agglomerates,the segregation of ore by size which occurs from handling will be reduced and channeling minimized. A stronger agglomerate will reduce fines migration during leaching and prevent blinding of the heap, Both of these changes will give an even flow of barren solution throughout the heap and give solution contact with all of the ore. This paper presents the development of polymeric agglomeration aid, Nalco 9760 which has given a higher rate of and a higher total gold recovery in plant evaluations.

Jan 1, 1990