Search Documents

By Shoji Taniguchi, Lifeng Zhang, Kaike Cai

"In the present paper, based on the two-phase (Eulerian-Eulerian) model, the 3D fluid flows in gas-stirred systems, i.e., air-stirred water vessel and argon-stirred liquid steel ladle, are simulated. In the Eulerian-Eulerian two-phase model, gas and liquid are considered to be two different continuous fields. The phases are assumed to share space in proportion to their volume fractions. The exchange between the phases is represented by source terms in conversation equations. Turbulence simulated by the k- e model is assumed to be the property of the liquid phase. The following effects of mathematical treatments and operational factors on the fluid flow are discussed, such as interphase drag force, turbulent model, the size of bubble, and gas injection mode.Some interesting results are derived. Except the interphase drag force, the interphase lift force should be taken into accounted in order to exactly simulate the fluid flow in gas-stirred systems. Suitable turbulent model and drag coefficient have effect on the mathematical simulation. Injecting small bubbles can realize a well mixing flow condition. The distance between the two gas-injection nozzles has effect on the fluid flow."

Jan 1, 2000

By P. F. Venus

In December 1977, a large pillar was removed by blasthole mining methods at lnco's Creighton No. 3 mine. Although the 2,363.000-ton blast was not a size record for a single underground blast at Inco, it did represent a significant departure from conventional blasthole mining. In terms of the application of nominal 6-inch-diameter boreholes underground, coupled with bulk slurry explosives, the magnitude of the blast is considered a first and very important development. The application of large-diameter boreholes in underground operations was first tried successfully in 1973. Since that time over 13/4 million feet have been drilled in this adaptation of an open-pit technique to underground operations. The blast, which required 708 holes, totalling 131,500 feet of drilling, was loaded in a six-week period, using special slurry handling techniques developed jointly by Inco and CIL. Inco operating and engineering personnel consider this application of large boreholes and slurry explosives for blasthole mining a very important milestone in modern mining technology.

Jan 1, 1978

By Kenneth E. Hay

The Bureau of Mines collected coal and coal waste aggregate material from two different mine sites to determine their strength characteristics for use in concrete. The concrete would be placed underground as support walls for ground control in adverse conditions or unique mining applications. A standard mix design was established for a "wet" mix using a water-to-cement (w/c) ratio of 1.0 to facilitate pumping into place. Later, material was collected from four more mine sites and used to make 2-by 2-by 2-ft test blocks with the same w/c ratio. A pull-out cone device and borehole shear tester were used to determine the in situ material strength of the test blocks. These techniques will provide a simple and quick way of determining support wall strength in an underground environment. Test results from the pullout cone de-vice showed a good correlation of 0.98 to test cylinder compressive strengths of the same mix. Results of the borehole shear tester were inconclusive.

Jan 1, 1986

By Paul Riches

LR Process Expert is a cost-efficient process automation system for all types of long rolling mills, including, rod, bar, section, rail, reversing mills, and flat blocks. The system performs a wide range of tasks for optimized operation – from suggesting pass schedules to calculating and downloading optimized mill settings according to the availability of rolls. LR Process Expert also monitors and collects data from the raw material stage through to the finished product. It delivers valuable mill reports to the operator staff and management so they can easily assess a plant’s performance and optimize production. Defined Key Performance Indicators (KPIs) help to assess a plant’s performance; this system is not limited to one plant but can enable plant-toplant performance at corporate level.

Aug 16, 2017

By William H. Schiffbauer

This report details a microcomputer-based control and monitoring network that was developed in-house by the U.S. Bureau of Mines and installed on a continuous mining machine. The network consists of microcomputers that are connected together via a single twisted-pair cable. Each microcomputer was developed to provide a particular function in the control process. Machine-mounted microcomputers, in conjunction with the appropriate sensors, provide closed-loop control of the machine, navigation, and environmental monitoring. Off-the-machine microcomputers provide remote control of the machine, sensor status, and a connection to the network so that external computers can access network data and control the continuous mining machine. Because of the network's generic structure, it can be installed on most mining machines.

Jan 1, 1993

By John V. Beall

The Mining Engineering Handbook is written primarily for persons interested in the economic extraction of minerals. Not everyone referring to this book will be knowledgeable about mining and, therefore, this section is intended to explain to interested persons the scope of mining as well as fulfilling the title of "Mining's Place and Contribution" among the industries of society. 1.1-MINERALS, ROCKS AND ORE In the year 1971, the number of known elements amounted to 104. Fifteen of these have been made only in the laboratory, others may have persisted from the primitive atmosphere, but, by and large, elements originated from magmas or igneous rocks of the outer rocky shell of the earth. Only eight elements constitute 98% by weight of the earth's crust. These are oxygen, 47%; silicon. 28%; aluminum, 8%; iron, 5%; and sodium, magnesium, potassium and calcium, less than 4% each. These common elements and the other less common ones are the building blocks of minerals, of which there are over 2,000 varieties. According to Webster: "A mineral is an inorganic substance occul.ring natura!ly in the earth and having a consistent and distinctive set of physical properties and a composition that can be expressed by a chemical formula. The term is sometimes applied to organic substances, such as coal." Thus, minerals are precise combinations of elements. Rocks, as distinct from minerals, are composed of assemblages of minerals. When minerals are found in sufficient concentration to warrant extraction by mining, the mineralized area is considered an ore deposit. The definition of ore is mineral that can be extracted from the ground at a profit. The economic connotation is implicit in the word ore. Since most of the useful elements compose such a small percentage of the earth's crust, the occurrence of ore deposits as we know them would not have transpired had not geologic processes concentrated the elements (see Sec. 4). 1.2-DEFINITIONS OF MINING TERMS Extensive coverage of the many descriptive terms used in mining may be found in a good mining glossary, such as is available from the Superintendent of Documents (see Sec. 35), but for convenience a number of the more common definitions are given here. Mining may be defined, as by A. B. Cummins, as the act, process or work of extracting minerals or coal from their natural environment and transporting them to the point of processing or use. Mining techniques are applied to extracting metallic minerals, such as ores of gold, copper, lead or zinc; to fuels, such as coal, anthracite, lignite and tar sands; and to nonmetallic minerals, such as lime-

Jan 1, 1973

By Dilip Kumar Mohanty

In today?s world, Sustainability is the key issue before the mankind. With the ever-increasing population & unimaginable boost in industrial growth to cope up with a steady increase in demand and fast change in life style of a human being, the natural resources are exploited to such an extent that the very existence of living beings in this earth planet is threatened. In such devastating situation, the concept of Sustainability emerges out as a great savior. This concept focuses on minimum/ judicious use of natural resources, thereby preserving the resources for future generation while meeting the bare minimum requirement of the present generation. For an emerging economy like India, Mining and Mineral based industries form the back bone of our economic development. Thus, sustainability of mining and mineral processing industry has a far reaching impact on sustainable economic development of our nation. While at a macro-economic level, we have to strike a balance between economic development vis-à-vis socio-economic & environmental impacts, Industries have to ensure judicious and frugal use of natural resources by making use of energy efficient plants & machineries and adopting befitting technology for reduction & recycling of waste. In the context of the above, it would be interesting to look into the sustainability measures taken up by National Aluminium company (Nalco) at its Crushing & conveying plant at Panchpatmali Bauxite Mine, which is incidentally Asia?s largest Bauxite Mine. In the backdrop of the above stated facts, in this paper the authors make an attempt to bring out the sustainability issues in areas of energy conservation, environmental impact/pollution vis-a-vis mitigation measures adopted in crusher & conveyor plant of Panchpatmali Bauxite Mine & CSR / peripheral developmental activities undertaken by Nalco to mitigate the socio- economic impacts. Keywords: sustainability, energy efficiency, recycle, csr, peripheral development

Sep 1, 2012

By Kirsi M. Riihilahti

The oxidation characteristics of solid copper matte particles under simulated Kennecott-Outokumpu Flash Converting conditions are presented. This project is concerned with the determination of the effects of operating variables on the reaction of the particles. Experiments were carried out in a large laboratory-scale flash furnace with 72 wt-% Cu matte by varying initial particle size, temperature, oxygen partial pressure, oxygen-to-matte mass ratio and residence time. Chemical analysis was used to study the oxidation extent and copper volatilization. Particle fragmentation was examined. Fractional conversion and sulfur removal slightly decreased with initial particle size, while a higher oxygen-to-matte mass ratio mainly resulted in higher fractional conversion and more efficient sulfur removal. The fractional conversion values represented the overall extent of oxidation more closely than degree of sulfur removal.

Jan 1, 1997

By Stanko Nikolic

One of the keys to success in process development is incremental scale-up, allowing for potential problems to be identified and rectified. The ISASMELT™top submerged lance (TSL) process was developed to maturity using this method by Mount Isa Mines, now owned by Glencore. Commercialization only occurred once the process had been proven on each scale and as a result the ISASMELT™ technology now operates successfully around the world. An important parameter in the evolution of the technology has been the furnace campaign life. The initial commercial scale furnaces had minimal water-cooling. Although this led to shorter campaign lives, an extended development program resulted in the achievement of four-year campaign lives, without any water cooling. In tandem to the refractory designs Glencore Technology, supplier of the TSL technology, has progressed cooled copper lining designs for application to both the ISASMELT™ and ISACONVERT™ furnaces allowing for ultimate flexibility in the lining choice. This allows each ISASMELT™ operating site to minimize their overall life-cycle costs by balancing their campaign life with lining costs, energy inputs, and other shutdown requirements.

By Michael Casson

With the mining industry changing rapidly due to mergers, acquisitions and fluctuating market pricing, today?s market for coal, minerals, ores and aggregates demands electrical apparatus that perform every time with maximum efficiency and with consideration for personnel safety. This is especially true in existing mining operations where every payload counts. Draglines are the workhorses of surface mining operations, and reliable and efficient operation is absolutely critical to success. However, the inherent disadvantages of using dc motors and motor-generator (MG) sets can significantly impact productivity and return on investment (ROI).

Jan 1, 2013

By Jue Kou, Lei Yu, Bern Klein, Lusheng Zhou, Chunbao Sun, Genzhuang Li, Reem Roufail, Amit Kumar

Magnetic liners can improve the performance of ball mills by increasing grinding efficiency, extending service life, and reducing maintenance costs. Despite their importance, the fundamental understanding and the quantitative investigation on the effects of the magnetic liners has not been addressed in the literature. This paper addresses this gap by studying charge motion, and how the use of a magnetic liner affects the breakage mechanism of the mill, using discrete element method (DEM) modeling and the Hertz-Mindlin contact model with relative velocity dependent (RVD) rolling friction. Charge motion was modeled under different mill speeds. Compared to conventional steel and rubber liners, the charge motion in the magnetic liner mill was predominantly cascading. Quantitative analysis of the energy dissipation within the mill was conducted to investigate mill breakage. Regardless of speed, over 50% of the total energy dissipation in the magnetic liner mill was in the form of abrasion and attrition. The results highlighted the appeal of magnetic liners in secondary and regrinding application, where abrasion and attrition are considered more efficient in the fine material breakage, and where impact is ideally minimized to reduce mill wear. A number of experiments were conducted to assess the effect of different model parameters on the performance of the magnetic liner mill. The highest abrasion/attrition intensity was observed with high values of the model parameters namely the restitution coefficient, static friction coefficient, and rolling friction coefficient.

By D. E. Walsh

The behaviour of gold particles on a spiral was studied using radioactive gold tracers. The method allowed the effect of particle size, particle shape, pulp density, feed rate, and splitter settings to be studied. Although the method has been successfully applied to other gravity concentrators, it was found that reliable results were more difficult to obtain on the spiral. However, these preliminary results show that provided suitable precautions are taken, the technique is capable of providing valuable information that cannot be obtained by conventional studies, and could be used to better optimize spiral performance.

Jan 1, 1992

By A. O. Drysdale

In Canada, the market for cement is not a national one but rather a collection of local or regional markets. Excess capacity on a national basis does not necessarily preclude a shortage on a regional basis. with portland cement selling for less than a cent a pound, the low price-to-weight factor makes transportation to the market a major cost item and thus a small plant can be justified to serve a limited regional market. The Brookfield plant of the Canada Cement Co. is designed to supply the Province of Nova Scotia, a regional market that shows promise of growing to a point where it will support a one-kiln plant. The market is presently being served by boat shipments from the Canada Cement Co. plant at Montreal East, Quebec, and from the North Star Cement Ltd. plant at Corner Brook, Newfoundland, and by rail and road shipments from the Canada Cement Co. plant at Havelock, N. B.

Jan 4, 1965

By M Scoble, C Hughes, M Roberts

At 14 per cent, the representation of women working in the mining industry is the lowest among primary industry categories in Canada. Despite an increase in research and industry commitment to advance and retain women in the mining industry, the gender gap in mining organisations persists.This paper is based upon a recent Canadian survey of 163 highly qualified women (HQW) working in the mining sector. For the purpose of this research, HQW were defined as women with a BachelorÆs degree or higher. This research sought to identify career progression and retention patterns of women who in theory have the educational qualifications to advance into positions of leadership in mining operations. We considered why womenÆs advancement in mining organisations has stalled; examined the career development pathways of HQW; and investigated the interactions of mining workplace culture on HQWÆs career development and retention within the Canadian mining industry. Results?indicated two distinct career pathway trends for HQW. æThe specialistÆ; a career characterised by multiple professional scientific and technical positions, and æthe corporateÆ; a career characterised by professional administrative roles and roles in mid-level management. It was found that neither æcorporatesÆ nor æspecialistsÆ systematically progressed into senior management and executive roles. These findings suggest that HQWÆs careers in mining are stalled, despite a strong indication by respondents of interest in their professional career advancement. With regards to?workplace?culture, respondents indicated that blatant forms of gender discrim-ination have been reduced in mining workplaces; however, exclusion from informal networks, implicit bias and subtler forms of workplace discrimination persist. Consistent with previous mining sector research, improving work-life balance, work flexibility and mentorship were found as key drivers for HQW to advance and remain in the industry.CITATION:Hughes, C, Scoble, M and Roberts, M, 2012. Where are the women? Highly qualified women in the mining industry, in Proceedings International Mine Management 2012, pp 23-34 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 20, 2012

By Martin Hertzberg

The early and reliable detection of the self-heating of combustible substances in mines is of considerable importance to the mining community. This Bureau of Mines report describes the results of a variety of studies of incipient combustion and its detection. Heated samples of coal, wood, and various polymers were used to evaluate the relative sensitivities of several types of detectors. The laboratory results indicate that submicrometer particulate detection is the most universal and sensitive method. Carbon monoxide detection was as sensitive as submicrometer particulate detection for pyrolyzing coal but was relatively insensitive to pyrolyzing wood or plastics. The conventional type of ionization smoke detector was the least sensitive for coal and of intermediate sensitivity for wood and plastics. Self-heating experiments with Pittsburgh seam coal piles of varying particle sizes gave ignition temperatures of 170° C for 4-to 7-µm dust, which increased monotonically with particle size. The measured heating rates were compared with data from an adiabatic calorimeter to obtain preexponential rate constants. The preexponential rate constants varied linearly with the surface area per unit mass of sample as would be expected for heterogeneous surface oxidation. The propagation behavior of ignition waves and the overall self-heating appears to depend critically on the magnitude of the convective flows induced, which counteract the depletion of oxygen in the void spaces of the pile. Classical theories of thermal ignition require substantial modification to be applied reliably to such cases.

Jan 1, 1977

By X X. Qiu, T Zhang, B L. Wang, X Qiu, Y H. Du

This paper summarises the information about current state of eco-environmental problems, geological disaster and mining waste causing during the process of limestone mining. By comparing the management experiences of limestone mines in other countries, management problems in China have been discussed and improved management options have been proposed here. These options include: accelerating the process of legislation, promoting and strengthening environmental impact assessment for limestone mine, and increasing compensation requirements according to the local eco-environment conditions.CITATION :Wang, B L, Qiu, X X, Qiu, X, Zhang, T and Du, Y H, 2012. Eco-environmental problems caused by the process of limestone mining and management options, in Proceedings Life-of-Mine 2012 , pp 357-360 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

By Gergely Markos

Uranium mill tailings represent a potential threat to the human habitat by containing large amounts of radioactive and chemically toxic substances in high concentrations. These: undesired components enter the human habitat in various pathways such as by erosion and water or air transport. The main objective of this investigation was to evaluate the actual movement and model the potential movement of contaminants by seepage of water from the tailings into the subtailings soil. This report represents various models of the movement of contaminants using both theoretical approaches and empirical evaluation of data available from other investigations. The data consist of field measurements and laboratory determi¬nations of major and trace cations, the dominant anions, pH, and Eh of moist solids, extracts, and waters from the tailings and surroundings. Evaluation and interpre¬tation of data were accomplished by using Eh-pH diagrams, various statistical methods and the WATEQFC computer program. Data analyses show that the critical area of investigating movement- is the interfaces between tailings and the external environment. The chemical differences at interfaces seem to result in a sink system for contaminants. The tailings-soil¬-water system shows extreme complexities because of chemical and physical hetero¬geneity of the system preventing the use of a single comprehensive model to represent real conditions. The validity of the simplifying assumption used has been shown and increasing complexity has been built into the models. Analogs of these models can be used for evaluation of similar systems.

Jan 1, 1981

By R. C. Buehl

A pyrometallurgical process for recovering manganese from open-hearth furnace slags or low-grade manganiferous iron ores is described. The slag or ore is smelted in a blast furnace to produce spiegeleisen; the speigeleisen is then blown with air in a basic converter to give an oxide slag. This slag product contains 60 to 75 percent manganous oxide and may be considered a synthetic manganese ore. In the smelting operations coke rates for five test periods ranged from 3,255 to 4,130 lb per ton of spiegeleisen. The recovery of manganese in the spiegeleisen varied from 60 to 76 percent. Recovery increased to 83 percent when the open-hearth slag feed to the blast furnace was diluted with a high-? grade iron ore sinter to facilitate smelting. In blowing the spiegeleisen a cyclic procedure was developed that gave nearly 90 percent recovery of manganese in the slag product (synthetic ore) yet prevented excessive contamination of the slag by phosphorus and iron. The overall recovery of manganese was about 75 percent when iron ore sinter was used with the open-hearth slag in the smelting step. The metal remaining after oxidizing the manganese from the spiegeleisen contained approximately 3.5 percent phosphorus. It was refined in a basic converter by blowing with air in the presence of lime" A high--grade iron and a basic phosphate slag were produced.

Jan 1, 1965

By D. A. Huggins

Column flotation is finding increasing use in the flotation of copper, molybdenum and other heavy metals and coal. Columns have proven operational, cost and metallurgical advantages which caused us to investigate their use in the proposed Escondida flowsheet. A comparative pilot plant test with 35 tons of ore showed that one column can replace three stages of cleaning and result in a significantly higher concentrate grade with no loss in recovery.

Jan 1, 1987

By Z. Zhang, M. S. Gonzalez, M. de P. Bueno, P. Holopainen, S. Luukkanen

In an extremely competitive mining industry, onsite experience is a big advantage. Mining education at the universities is mostly focused on theoretical studies without a possibility of practical training in mining sites. Hence, experimental mines suitable for practical education are needed to provide a platform for systematic research and education in industrial scale and for training in real mining conditions. Yet, this kind of mine sites is rare worldwide. Thus, a new educational research project, namely MINETRAIN is introduced in this paper evaluating the transition of the Pyhäsalmi mine in Central Finland from an active base metal mine to a research, educational and training underground facility. The uniqueness of MINETRAIN compared to other test mine programs is that the existing state‐of‐art infrastructure in Pyhäsalmi enables research and training facilities among all disciplines related to the overall mine value chain. Though all the above sound interesting in the context of research and education purposes, in practice Pyhäsalmi will have to become an experimental mine that can be sustainable in the future. Accordingly, a prefeasibility study is being conducted and some preliminary results are presented in this paper. INTRODUCTION Despite being a field of studies that requires practical knowledge and experience, mining engineering education follows the same pattern in most mining universities around the world; consisting of theoretical courses and laboratory-based practical modules (Mischo, 2015). The possibility of having practical training in real mining conditions on actual mine sites or processing plants is limited to none, while the only contact that undergraduate students have with mining operations during their time of studies is usually through short-time internships or visits in the context of educational trips. Yet, real integration between universities and the mining industry may be scarce, which does not help students to observe the actual processes, and thus understand the whole picture of mining operations. Indirect practical training is also possible nowadays that technology is shifting from mechanical to digital, and the use of virtual reality -in the context of Mining 4.0- can provide additional experience to the learning process. However, virtual reality is limited to the visual impression and is also limited in actions (Binder et al, 2018). In any case, when there is not a proper pragmatic view of how the different disciplines link to each other and especially if there is a lack of communication, unfortunately the results could be seen at a later stage in the mines as a poor performance of professionals and workers. Another major challenge for educating specialists in the mining sector is that experimental mines suitable for practical education, where the skills and know-how could be developed and/or enhanced are rare worldwide. Such research and educational (R&E) facilities are practically former metal ore mines that have been transformed into experimental sites. Besides being limited in number, not all facilities of this kind serve both a research and educational purpose.

Jan 1, 2019