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By M. Polat

Variations in flotation rate by particle size and specific gravity have been investigated for three different bituminous coals. The flotation rates for various components were determined by separating the products of bulk flotation into size-specific gravity fractions. The effects of feed size and reagent addition on the flotation response of individual size-specific gravity fractions were evaluated.

Jan 1, 1994

By A. Bergmann

Location The Meggen Mine and the concentrator plant of the "Sachtleben Bergbau G.m.b.H." are located in the southern part of the Ruhr-district of the Federal Republic of Germany. The mine has been in operation for more than 100 years, but the concentrator described in this paper was built in 1962 and started up in January 1963. Goelogy and Mining The Meggen ore-body is of sedimentary origin and occurs in a zone of limestones, graywacke and shales of Devonion age. The average thickness of the deposit is 3 meters and, due to an intense folding of the area, the mineralized zone dips very steeply at 800 toward the north. The ore consists of 85 percent of sulfides and 15 percent gangue that mainly contains silicates from the host rocks. The principal ore minerals are pyrite (67 percent), sphalerite (16 percent) and galena (2 percent) with minor amounts of marcasite and only traces of chalcopyrite. As shown in Fig. 1, the sphalerite and galena are very finely disseminated in the massive pyrite of the Meggen ore, and a very fine grinding combined with a special flotation technique are required to liberate the valuable sulfides and to produce separate concentrates of lead, zinc and pyrite. Mining is performed by the sub-level stoping method and employs trackless equipment. Present operations provide ore from the 600 meter level. Annual ore production is 870,000 metric tons.

Jan 1, 1972

By J. L. Watson

n the U.S., lead has been produced via blast furnace processing for over a century, and the slags from that pyro-metallurgical process have been accumulating on industrial sites over that extended period. Lead blast furnace slags typically contain both lead and zinc compounds in an iron-silicate matrix, and it appears highly likely that such materials will have to be processed in the near future to meet with EPA regulations. Thus it is appropriate to investigate possible processing routes to render the slags non-hazardous and simultaneously to recover metal values to partially off-set the inherent high cost of processing such materials. There are two major processing alternatives: one being pyrometallurgical and the other hydrometallurgical. The research reported here investigates leaching/solution purification/recovery processes for lead and presents experimental data for the treatment of lead blast furnace slags from S.E. Missouri. The results of the research suggest that both lead and zinc can be removed effectively from the slag, and that metallic lead can be recovered directly from the organic extractant utilized for solution purification.

Jan 1, 1995

By Jr. Gambrell

For more cost effective strata control, a fundamental understanding of the behavior of the support system is needed. To assist in this understanding for shield supports, behavior of a four-leg shield design used on a soft floor in an operating longwall system is presented. The shield was constructed having a split base and a split caving shield. Attention is focused on other-than-normal loading on the canopy and its effect on deformation of the lemniscate links. Examples of the typical bending and twisting deformations are given. Schematics of the canopy, caving shield, and lemniscates showing important forces and moments are presented. Approximate minimum values of the forces and moments are calculated. The need for use of more inclusive three-dimensional design techniques is demonstrated.

Jan 1, 1990

Over the years, numerous studies have been conducted to characterize the floatability of coal pyrite. Unfortunately, many of the results obtained using isolated samples of coal pyrite are not directly applicable to actual coal flotation systems where liberation and entrainment may be the major factors affecting pyrite rejection. In this paper, the association of pyrite with other coal constituents is investigated, and the data are presented for feed and product streams obtained from release analysis tests. Release analysis is used to minimize the effects of entrainment. Particle distributions for each stream are presented as functions of size and composition in order to discern the behavior of free and composite particles.

Jan 1, 1992

By V. P. Keran

Design of the Bajo de la Alumbrera Project started in June 1995 and concentrate production commenced early in the Third Quarter of 1997. The project is situated in North-Western Argentina and is being developed by Minera Alumbrera Limited which is owned by MIM Holdings Limited of Australia (50%), North Limited of Australia (25%) and Rio Algom Limited of Canada (25%). This paper outlines the key features that were incorporated in the design from both process and plant layout perspectives. It explains the background of flowsheet and equipment selection for the plant. A feature of the flowsheet is that it incorporates gravity gold circuits in both primary and regrind circuits for recovery of gold to dore as well as in the copper concentrate product.

Jan 1, 1998

By J. M. Dean

With the continued downward pressure on coal selling prices, mine management must make its operations as efficient as possible. The problem is the same one throughout the mineral industries, streamlining operations to maintain competitive mining costs (Born, 1991). There has been a great deal of research into better using production manpower. But the story is different for operations support personnel. Traditionally, planning man-power requirements are done annually, with modifications to the operating plan occurring generally quarterly. On the other hand, the demands on manpower are often dynamic, being responsive to changing productivity levels ,mine conditions (including water influx, bad roof, poor floor)and unanticipated project requirements (responses to machine breakdowns or a new section setup requirement because of a drop in coal quality in another area). Such changes may impact the manpower structure significantly. At times they may cause serious labor relations problems concurrently. Realignments and the generation of instability in the workforce because of active job switching (bidding) are a result. Most responses by coal operators are reactive rather than proactive, a situation that could be mollified by more accurate and detailed planning of predictable manpower requirements. A manpower planning tool is needed that takes into consideration such things as changing productivity levels and conditions as manhour requirements for different work areas are planned, rather than blindly allocated through traditional staffing modes.

Jan 1, 1995

By Sebastian Avalos, Julian M. Ortiz, Willy Kracht

Semi-autogenous grinding mills play a critical role in the processing stage of many mining operations. They are also one of the most intensive energy consumers of the entire process. Current forecasting techniques of energy consumption base their inferences on feeding ore mineralogical features, SAG dimensions, and operational variables. Experts recognize their capabilities to provide adequate guidelines but also their lack of accuracy when real-time forecasting is desired. As an alternative, we propose the use of real-time operational variables (feed tonnage, bearing pressure, and spindle speed) to forecast the upcoming energy consumption via machine learning and deep learning techniques. Several predictive methods were studied: polynomial regression, k-nearest neighbor, support vector machine, multilayer perceptron, long short-term memory, and gated recurrent units. A step-by-step workflow on how to deal with real datasets, and how to find optimum models and final model selection is presented. In particular, recurrent neural networks achieved the best forecasting metrics in the energy consumption prediction task. The workflow has the potential of being extended to any other temporal and multivariate mineral processing datasets.

Jun 16, 2020

Solvent extraction-electro- winning appears to be one of the most important processes for the future in the North American copper industry and for this reason both the SX and EW steps are furtive areas for development. This paper has the objective of reviewing the present state of the electrowinning technology. It discusses some recent equipment developments and concludes by discussing the direction the technology will likely go fn the next decade.

Jan 1, 1985

By W. C. Hirt

Selective flocculation was used to produce superclean zinc concentrate with minimized silica contamination. Research was carried out on a flotation concentrate from the Jersey Miniere Zinc Company (JMZ) in Gordonsville, Tennessee. The material was first dispersed with sodium silicate and then causticized tapioca starch was used to selectively flocculate the sphalerite, leaving the silica in suspension. This technique has been applied commercially to iron ore beneficiation but has never been used for processing zinc. The feed material assayed 0.45% Si02. Use of 0.56 kg/tonne (1.13 lb/st) of sodium silicate and 0.070 kg/tonne (0.141 lb/st) of causticized tapioca starch resulted in 98.2% zinc recovery in a purified zinc concentrate assaying 66.0% Zn and 0.24% silica. The present target level for silica contamination in JMZ zinc concentrates is 0.3% Si02. This work has shown that selective flocculation offers a potential method for cleaning flotation concentrates, particularly where low silica products are required.

Jan 1, 1993

By M. Z. Mubarok, Z. T. Ichlas, A. T. Sugiarto, K. Sukamto

The use of ozone as an oxidant for the direct leaching of zinc sulfide (sphalerite) concentrate in sulfuric acid medium under atmospheric pressure was explored. The influence of acid concentration, feed gas injection rate, particle size distribution, stirring speed, temperature and slurry density on zinc extraction efficiency was examined. The experimental results showed that the leaching efficiency depends on all of these operating parameters except for stirring speed. It was found that essentially complete dissolution of zinc from the concentrate with the present method can be achieved in only about seven hours under the conditions of sulfuric acid concentration of 2 mol/L, particle size smaller than 74 µm, slurry density of 50 g/L, stirring speed of 420 rpm and feed gas injection rate of 1 L/min at ambient temperature. The experimental results suggest that the dissolution reactions produce independent elemental sulfur that is readily floated and can be easily separated rather than forming a layer on the surface of the reacted particle, as usually observed in a system with ferric-sulfate as oxidizing agent. It was therefore determined that the dissolved ozone play a key role in improving the rate of zinc dissolution from the concentrate. Analysis of the leaching kinetics indicate that the leaching rate follows the shrinking particle model, and the overall dissolution rate of zinc is controlled by a surface reaction.

By Ronald M. Hays

During the twentieth century the Mesabi Range in northeastern Minnesota has been the major source of iron ore for American steel mills. The Mesabi Range extends along an iron bearing outcrop known as the Biwabik formation. This outcrop is some 120 miles long and up to three miles wide. The formation is from 200 to 650 feet thick and dips 5 to 10 degrees to the southeast. The iron content of the original Biwabik formation was quite uniform, but much of this formation has been subjected to alteration. Thus major variations in iron content and mineral composition exist both laterally and vertically in the present Biwabik formation. The remaining unaltered iron formation includes the magnetic taconites which are commercially processed by Reserve Mining, Erie Mining, Eveleth Taconite, National Steel, Butler Taconite, and U.S. Steel. These six operations have a capacity of 32 million tons. per year of iron pellets and have produced approximately 170 million tons of pellets since 1956. Capacity for another 30 million tons per year of pellets is being considered by the industry for the next ten years. This increase will be obtained by construction of new plants and expansion of present operations. Thus by 1977, it is estimated that approximately 60 million tons per year of iron pellets will be produced from magnetic taconite on the Mesabi Range. The portions of the Biwabik formation subjected to intense alteration resulted in the direct shipping, wash and heavy media ores. Since 1892, 1.8 billion tons of direct shipping ore have been shipped from the Mesabi Range. This ore has been the major source of iron for American steel mills. In 1966, 12 million tons of direct shipping ore and 18 million tons of wash, jig, heavy media and other gravity concentrates were shipped from the Mesabi Range. These products generally have poorer physical and chemical properties than the iron pellets produced from magnetic taconite. It is predicted that the shipment of these materials will decrease from about 30 million tons in 1966 to 6 to 8 million tons in 1975. This decrease will be due to depletion of reserves and poor quality product.

Jan 1, 1968

Global mining company achieves significant productivity gains with three-dimensional (3D) mine models developed with Abaqus finite element analysis software. In a steep change beyond traditional processes, Abaqus finite element analysis (FEA) software from Simulia (the Dassault Systèmes? brand for realistic simulation), is being used to enhance mine design and engineering simulation at a number of major mines around the world. In North and South America, Africa and Australia some of the world?s biggest mining companies are applying FEA technology to evaluate safety and improve design planning, implementation and operations. Beck Arndt Engineering (BAE), a Sydney-based international consultancy, is a pioneer in the commercial development of engineering solutions for the mining industry. The consultancy has worked closely with engineers at Simulia Australia to expand the use of Abaqus FEA simulation software for mining applications. Among the early adoptors of mine-ready FEA technology is the world?s largest miner, BHP Billiton. With BAE?s help, BHP has already applied this technology to evaluate mines in Canada and Australia. At the BHP Billiton Nickel West Perserverance Deeps Project in Western Australia, Abaqus FEA software is now being used to help engineer the safety and productivity of planned deep-mining operations. To achieve this goal in the deep-mining environment significant technological innovation is required. Using measurements of site deformation and seismicity, Abaqus FEA models have been calibrated and, in a single day, used to simulate a full, 3D, inelastic analysis of a mine?s life cycle. In recent years, similar applications at Debswana?s Jwaneng Mine in Botswana, the Newcrest Mining Ridge-way Deeps Project in New South Wales, Australia and Rio Tinto?s Argyle Diamond mine in Western Australia have also established Abaqus FEA analysis as the lead-ing technology for multi scale, simulation-aided mining engineering. Joop Nagtegaal, a pioneer of FEA and a Dassault Systèmes Corporate Fellow, said that Abaqus FEA software is unique in its capabilities to enable mining engineers to investigate design innovations from the drawing board to full production. ?In the design stage, Abaqus models, which include rockmass volumes spanning several kilo-meters around the ore body and down to excavations just a few meters across, are used to compare and optimize engineering options,? Nagtegaal said. ?Then, as the mine goes into production, large volumes of data from the field are incorporated with the analysis models to allow them to be calibrated to a precision not previously available to the mining industry.?

Jan 1, 2009

By X. P. Zheng, H. K. Lin

Barium fluorophlogopites were synthesized in the laboratory to investigate the effects of composition and crystal parameters on surface properties and floatability. The negative surface charge of mica is determined by the barium content, the crystal cell volume, the distance between the layer structure and the Ba-O bond length. The higher the barium content, the larger the cell volume and distance between the layer structure, and the longer the Ba-0 bond, the more negatively charged the surface is, and, hence, the more easily adsorbed are cationic collectors. When an anionic collector (sodium oleate) is used, barium oleate forms on the mica surface and hence chemical adsorption occurs.

Jan 1, 1995

The dissolution kinetics of cobalt in iodine/iodide solutions was investigated using a rotating disc technique. Variables studied here included temperature, rotating speed, concentration of lixiviants, and pH of the solution. The overall dissolution reaction was found to be limited by mass transfer of tri-iodide through the diffusion boundary layer with Arrhenius activation energy of less than 16.2 kJ/mol (4 kcal/mol) over the temperature range, 2-42°C. The pH of the solution had little effect as long as the pH of the solution was less than 8. However, when the pH of the solution became greater than 8, the dissolution rate decreased dramatically due to passivation. The rate of dissolution was in good agreement with the dissolution model developed by the authors earlier.

Jan 1, 1994

By A. K. Gangopadhyay

This paper discusses the effect of grinding media composition, mineral type and slurry environment on the wear rate of various grinding media (balls). Sufficient wear data have been obtained and correlated with the modes of wear determined from examination of the ball surfaces using scanning electron microscopy. Five modes of wear have been identified to be operative under certain slurry conditions for the various ball compositions studied.

Jan 1, 1984

By J. Hallowell, M. Conley, R. Cook

Inflatable friction rock bolts (IFRBs) are often considered temporary ground support due to their susceptibility to weakening from corrosion. The effective service life of an IFRB can be difficult to estimate due to the multitude of factors that affect the rate of corrosion. Some mine sites have experienced several-year-long service lives of IFRBs without issue, while others experience corrosion-related falls of ground only weeks after installation. The most common industry method of assessing bolt performance is by pull testing the fixture. However, due to the IFRB’s ability to mobilize its full tensile capacity with less than 2 feet of anchored length, corrosion along the bolt at depths greater than 2 feet from the collar cannot be identified using this approach. Alternatively, reinflation testing is a simple and non-destructive method of evaluating the condition of an entire bolt length for breaches in the bolt wall. This can be particularly useful when assessing the extent of corrosive conditions within a particular mining area where instabilities have already occurred and the condition of nearby bolts is unknown, or when re-entering historic mine workings which have not been monitored.

Feb 1, 2023

By T. Skodack

This presentation will compare actual work site results for the loading and transport of shot rock for two major tunneling projects in North America. "SCARMAR" (the Canadian subsidiary of S & M Construction) is operating a rail bound Hagglund continuous gathering arm loader in combination with a Hagglund nine car shuttletrain system at the West End of Table Mountain on the B.C. Railway project near Tumbler Ridge, Canada. Al Johnson Construction is operating a Hagglund rubber tired continuous gathering arm loader in combination with haul trucks at the Rocky Mountain Pump Storage Project near Rome, GA. This paper will compare: 1) tunnel and ground conditions, 2) the total work cycle as it relates to mucking and haulage 3) efficiencies and related problems with the two systems 4) mucking and haulage rates 5) operating costs, and 6) recommendations for future large tunnel excavations. Manuscript not received in time for publication.

Jan 1, 1983

By T. J. Lutz, S. Gallagher, J. R. Srednicki, J. J. Sammarco

The Illuminating Engineering Society of North America reports that an underground mine is the most difficult environment to illuminate (Rea, 2000). Researchers at the U.S. National Institute for Occupational Safety and Health (NIOSH) Office of Mine Safety and Health Research (OMSHR) are conducting ongoing studies designed to explore different lighting technologies for improving mine safety. Underground miners use different visual cues to escape from a smoke-filled environment. Primary and secondary escapeways are marked with reflective ceiling tags of various colors. Miners also look for mine rail tracks. The main objective of this paper is to compare different lighting types and ceiling tag colors to differentiate what works best in a smoke-filled environment. Various cap lamps (LED and incandescent) and lasers (red, blue, green) were compared to see which options resulted in the longest detection distances for red, green and blue reflective markers and a section of mine rail track. All targets advanced toward the human subject inside of a smoke-filled room to simulate the subject walking in a mine environment. Detection distances were recorded and analyzed to find the best cap lamp, laser color and target color in a smoke environment. Results show that cap lamp, laser color and target color do make a difference in detection distances and are perceived differently based on subject age. Cap lamps were superior to lasers in all circumstances of ceiling tag detection, with the exception of the green laser. The incandescent cap lamp worked best in the simulated smoke compared to the LED cap lamps. The green laser was the best color for detecting the tags and track compared to the red and blue lasers. The green tags were the easiest color to detect on the ceiling. On average, the track was easier for the subjects to detect than the ceiling tags.

Jan 1, 2013

By C. J. Im

As market conditions become more competitive, U.S. coal producers are faced with the increasing need to find methods of lowering production costs in their operations. One area worthy of investigation is the additional recovery of fine coal that is normally discarded in the preparation plant waste stream. United Coal Company is currently assessing the capability of the Deister Flotaire, a new application of a column flotation cell, to recover additional, saleable coal from preparation plant waste. This paper presents the technical data obtained to date. Work with a 0.76 m (30 inch) diameter cell installed in a plant shows considerable coal recovery is possible from a nominal 0.595 run (28 mesh) X 0 refuse stream.

Jan 1, 1986