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By Luzheng Chen

Pulsating high-gradient magnetic separation (PHGMS) of fine hematite from tailings was studied using a pilot PHGMS separator to investigate the possibility of its application in industry. The results of this investigation indicate that PHGMS is effective for recovering fine hematite from the tailings and greatly improved the separation performance compared with the conventional high-gradient magnetic separation at the same conditions. By applying the pilot separator with a 1-mm rod matrix to a tailings containing 28.76% Fe, a concentrate assaying 54.35% Fe with 35.89% recovery was achieved. It was found that the separation performance of the pilot separator closely correlates with the main pulsating parameters, i.e., pulsating stroke and frequency. It was also found that a change in the wire diameter of the rod matrix from 2 to 1 mm causes a weak drop in concentrate grade but results in a considerable rise in recovery. This finding proves that the improved performance achieved by the pilot separator is attributed to the pulsating of slurry and to the use of a 1-mm rod matrix. When the first commercial SLon-2500 PHGMS separator with a 1-mm rod matrix was applied to recover fine hematite from the tailings, the results duplicated those achieved with the pilot PHGMS separator.

Jan 1, 2009

By P. Mogodi

The purpose of the project was to propose a coal clearance system (coal transportation system from the mining face to the plant) that could be used for the planned underground operations at Zondagsfontein Colliery. Components of the current coal clearance system were overlooked during feasibility studies. Subsequent studies of the coal clearance system revealed that the combined capacity of the two trunk belts does not match that of the shaft (main) belt. As a result production downtimes will be encountered due to bottlenecks in the system. Ways of addressing this challenge were analysed by weighing both advantages and disadvantages and ultimately a surge bin option was selected. Belt conveyor simulations were conducted in order to determine the optimum capacity of the surge bin. The configuration of the surge bin in relation to the two trunk belts was chosen by considering development cost, advantages, and disadvantages of each option. It was concluded and recommended that a 500 tonnes capacity surge bin is required to remove the bottleneck from the system.

Jan 1, 2010

By Michael E. Berndt

Asbestos first became an issue to Minnesota?s iron industry when it was revealed that mineral fibers similar to those in Reserve Mining?s tailings were being found in drinking water for several communities that used Lake Superior as their primary water source. This discovery turned what had largely been an environmental court battle into a case concerning public health. The courts listened to much conflicting and uncertain scientific testimony on the size and distribution of the mineral fibers and on the potential health effects imposed by them. In April 1974, the plant was ordered to shut down by a federal judge but the company quickly appealed the decision. The appeals court granted a stay and ultimately ruled that the plant?s closure could not be justified based on the unknown health effects of the mineral fibers since the consequences of such an action would have immediate and severe social and economic impacts. The plant was allowed to continue operation, but ordered to abate emissions to air around the plant and to switch to a land-based tailings disposal system. Much of the scientific uncertainty and public concern over mineral fibers in Minnesota?s taconite industry remain today. ©2007 Elsevier Inc. All rights reserved. Keywords: Minnesota; Iron ore; Taconite; Asbestos; Amphibole; Reserve Mining; Tailings; Mesabi Iron Range

Jan 1, 2007

By I. M. Morsi, S. Z. El-Tawil, O. A. Fouad, K. A. El-Barawy, M. B. Morsi, M. M. Nasr

Upgrading of a low-grade titanium slag (~55% TiO2) with high silica, calcia, magnesia and iron contents has been studied using sulphation roasting technique using SO2/air gas mixture followed by hydrochloric acid leaching. XRD analysis of the sulphated slag reveals the presence of kennedyite (Fe2O3. MgO. 3TiO2), rutile (TiO2), calcium sulphate (CaSO4) and calcium silicate (3CaO.SiO2) phases. The residue after leaching contains mainly kennedyite, rutile phases and free silica with traces of calcium silicate phase. Synthetic rutile that has about 83% TiO2 can be produced at the optimum conditions. Thermodynamic calculations give rational explanations of the obtained results.

Jan 1, 2005

By R. Poisel, C. Scavia, Preh A., W. Roth, M. Pirulli

ABSTRACT: Two methodologies for the three-dimensional simulation of the run out of rock avalanches are presented: one based on a granular approach and the other based on a continuum equivalent approach. An evaluation of the possible run out area of the Oselitzenbach landslide (Carnic Alps, Austria) has been carried out applying the two methodologies. The combined use of these two approaches makes it possible a comprehensive assessment of the run out area. RESUME: Deux méthodologies pour la simulation tridimensionnelle de la propagation des avalanches rocheuses sont présentées: la première est basée sur un modèle de type granulaire et la deuxième sur un modèle du continu équivalent. Une évaluation de la propagation éventuelle de l’avalanche de Oselitzenbach (Alpes Carniche, Autriche) a été réalisée en utilisant les deux méthodologies. Les résultats obtenus montrent que la combinaison des deux approches rend possible une analyse plus complète de la phase de propagation. KURZFASSUNG: Für die dreidimensionale Modellierung eines Felsmassensturzes (sturzstrom) werden zwei Methoden, eine granulare und eine kontinuumsmechanische Methode, vorgestellt. Beide Methoden wurden zur Abschätzung der Ausbreitung (runout) der Massenbewegung Oselitzenbach (Karnische Alpen, Österreich) herangezogen. Die kombinierte Anwendung beider Methoden ermöglichte eine umfassende Beurteilung des möglichen Ausbreitungsbereichs.

Jan 1, 2003

By Thierry Bernard

This case study shows how a unique combination of field measurements and advanced technologies allowed blasters designing, loading and firing an incredibly challenging quarry blast.

Jan 1, 2015

By W. Stark

Many developing countries with little or no previous environmental regulation are now promulgating air quality regulations which require facilities to demonstrate compliance with both process parameter based emission limits and ambient air quality standards. For many companies with operations in developing countries, an air quality compliance program at the facility level is lacking and these companies have very little background information to work with in developing a program for assessing and maintaining compliance. This paper will present a methodology for development of a comprehensive air quality compliance program for operations located in developing countries with new environmental regulations. The experiences of the authors in developing an air quality compliance program for a mining operation located in South America will be used as a basis. A program for meeting new air quality requirements can be developed in seven steps. The seven steps are: (1) regulatory review and project scope; (2) design and implementation of a baseline air quality monitoring program; (3) site visit, (4) development of a complete air emission inventory; (5) dispersion modeling; (6) compliance analysis and compliance plan; and (7) project completion.

Jan 1, 1998

This report provides concepts for two automated longwall mining systems; one for operation in a 42 to 57-inch thick section of the Lower Kittanning coal seam, the other in a 57 to 72-inch thick section of the Pittsburgh seam. The Lower Kittanning concept uses a single-drum bidirectional shearer and 500-ton capacity 4-leg chocks and the Pittsburgh concept uses a double-drum shearer with 500-ton shields. Each concept is designed to produce in excess of 2,500 tons of clean coal per shift with a 6-man face crew. The automated longwalls consist of off-the-shelf control system hardware attached to standard longwall equipment. Control hardware includes a control and display console; prime and backup mini-computers; multiplex data transmission, power, and control lines; several remote terminals which serve as interface junctions; and various sensors and actuators located on the longwall equipment. The system can be operated either fully automatically, remotely or manually.

Jan 1, 1976

Beneficiation of Iron Ore - Washing with Surface-Active Agent The stability of the dispersed phase in 10 wt per cent slurry of iron ore slime and fines was studied at pH 5 and different concentrations of surface-active agents. The behaviour of the dispersed phase of iron ore slime and fines is different for different surface-active agents. The improvement of iron value of slime and fines in the presence of surface-active agent is best realized at pH 8, where the Al2O3/Fe and Al2O3/SiO2 ratios in the concentrates are appreciably reduced. The polar functional group like -COO- interacts with hematite surfaces and forms outer- and inner-sphere surface complexes depending on the suspension pH and adsorbate.

Sep 13, 2010

By Randy Wheeler

The importance of having full wave form information for recorded blast events cannot be overstated. Knowing the peak particle velocity and the frequency at the peak are the tip of the iceberg. This presentation will focus primarily on using the FFT (fast Fourier transform) for detailed frequency analysis. Employing linear superposition to evaluate timing effects on amplitude and frequency will be discussed.

Jan 1, 2005

By I. AITKENS

Tourmalines are among the most beautiful of all the semiprecious stones, and are unsurpassed even by corundum in variety of hue. The stones most suited to jewelry purposes are those comparatively free from iron. One reason for the fact that the tourmaline has advanced rapidly in public favor in this country is that it is found in California in great profusion and of extraordinary quality. The superb green and especially the pink crystals found at Pala and Mesa Grande in San Diego County, Calif., are deemed superior to tourmalines from all other localities.

Nov 1, 1931

By Stephen H. Chung, Kevin Atherton

The main purpose behind this preliminary study was the reduction of costs while maintaining productivity. Finding a way to achieve this balance without compromising controls on safety and quality of blasting results is of continual interest to the mining industry and of particular interest when ore of lower grade is being mined.

Jan 1, 1998

By K. A. Larsen, J. L. Ariail, C. M. LaRosa

This article discusses the evolution of U.S. laws and policies towards environmental remediation at mine lands over the last 20years, the opportunities that these changes present for reuse, and the remaining challenges associated with community capacity for effective reuse planning and implementation. Emerging initiatives by the U.S. Environmental Protection Agency and Department of Interior for addressing these challenges are discussed.

Jan 1, 2004

By G. Richards Gwinn

The mineral olivine, though known to mineralogists for many years, was of little commercial value in the United States before 1933. It was first described in 1790 by Johann Gottlieb Werner, who named it "olivine in allusion to its olive-green color. Commercial olivine first attracted attention because of its refractory properties. Further research has developed methods of extracting the magnesia content for the production of various magnesium compounds. Experimental and pilot-plant work also are in progress to make olivine available as a low-cost raw material for the production of magnesium metal.

Jan 1, 1943

By M. C. Malamphy

A general description of the activities and results of bauxite investigation by the Bureau of Mines at its bauxite project in saline and Pulaski Counties, Ark., has been given in Report of Investigations 4251. The factual data obtained during the project are reported in a series of Reports of Investigation beginning with No. 4251, of which this is the eleventh. The-data are accompanied by maps showing the location of holes drilled and the deposits developed. Each area upon which work was done is reported by half townships. Each bauxite deposit investigated was assigned a name and a number for ready reference and identification, and its location and name are shown on the appropriate half-township map. The description of each halt township is followed by a description of each deposit developed in that halt township. The 14 halt-township maps and 77 detail maps of the bauxite deposits in this series at reports give the locations and numbers of all the holes drilled on the project, except the deep holes drilled to test the geophysical anomalies. The locations of those holes show on figure 13 in volume 1. The descriptions of the deposits developed are followed by complete detailed logs of the drill holes. Many of the widely spaced exploratory holes did not discover bauxite of minable thickness and grade. The pertinent information obtained tram the widely spaced exploratory drill holes has been summarized and tabulated, and a table for each halt township is given with the discussion of that area.

Jan 1, 1948

By P. J. Suardini, T. E. Seppanen, M. J. Hanninen

In order to reduce the heat loading in the Tilden Mine kilns caused by burning coal, which in turn resulted in rapid and significant build-upon the kiln lining, internal carbon was added to the green ball prior to balling. Intensive laboratory testing led to three short-term full-scale plant tests that were successfully conducted. Appropriate environmental permits were obtained to allow Tilden to use internal carbon on a continuous basis. Findings concerning carbon addition rates, reductions in coal use, build-up reductions, fired pellet quality, and environmental issues will be discussed.

Jan 1, 2003

By Mackenzie Burnett

This program was initiated by USBM to quantify the respirable dust problem caused by the use .of roadheaders in underground metal/nonmetal mines with special emphasis on this problem in uranium mines. The contract called for the development of methods or equipment to alleviate the respirable dust and to implement the solution in a mine. Attempts to quantify the dust problem were made in the following way: survey of MSHA records, survey of state mine enforcement agencies, survey of mine records, dust measurements taken at two mines using roadheaders. The results of this study are not conclusive due to very limited and sometimes less than useful data; however, the study does indicate that a serious dust problem could and may exist. If and when roadheader use becomes more popular, it is almost certain that development of dust control procedures and equipment will be necessary. This contract was concluded without developing this equipment since only one roadheader is currently in use in an American uranium mine and the mine prefers not to participate in the program at this time. This report discusses the available data concerning respirable dust problems and presents a solution which can potentially help to solve the problem. The solution requires the use of blowing ventilation, on-board dust extraction at the source, and filtration, as well as continued use of water sprays. The on-site tuning of such a system is necessary to demonstrate the degree of improvement possible.

Jan 1, 1981

By Robert L. Lappi

Eight interburden handling concepts are developed for multiple seam area mine stripping operations in central and western United States. They are based on data gathered and analyzed during field surveys, literature reviews and visits to state requlatory agencies in five states. It is concluded that improvement of reclamation practices through selective interburden handling techniques is possible at lower operating costs than currently incurred. Specific multiple seam mining systems are discussed in this report.

Jan 1, 1980

By Christopher J. Bise

INTRODUCTION The principal means for transporting men, supplies, and mined material in an underground or surface mine are rail systems, conveyor belt systems, or a combination of the two. Typically, large underground mines use rail haulage from the mining sections to the hoist, with conveyor belts being used within the sections. Small mines use conveyor belts in the mains and sub- mains as well as in the panels. The size and layout of surface mines also contribute to variations in the way these haulage systems are applied. The following sections address the typical problems confronting mining engineers in designing these haul- age systems. For rail, these include rail selection and turnout design, locomotive tractive-effort calculation, and motor sizing. Belt haulage calculations include belt width and speed specifications, tension and take- up requirements, idler spacings, and motor sizing. TRACK LAYOUTS Introduction The adequacy of mine track layouts is dependent upon such factors as rail weight (Table l), suitable ties, a well-drained roadbed, and properly designed curves, grades, and track alignment. As long as the installation conforms to the manufacturer's recommendations, good service can be expected from the rail system. Typically, mining-engineering calculations for rack layouts have dealt almost exclusively with the design of turnouts. As such, the following section provides the necessary information for computing the theoretically correct dimensions of turnouts. Turnout Design Fig. 1 shows a typical turnout with an identification of the component parts. Fig. 2 identifies the variables that are used to determine the turnout dimensions. The formulas that concern the mining engineer are those listed: [ ]

Jan 1, 1986

By Thomas V. Falkie

Of the various critics of federal energy and minerals policy we are hearing these days--and they are legion--few make their points more vividly than our fellow SME member and eloquent spokesman for the mineral industry. Mr. Eugene Guccione. In a moment of comparative mellowness. Mr. Guccione recently characterized Washington's time-honored legislative and bureaucratic machinery as a case of "...scientific illiterates asking the incompetents to do the unnecessary." I hope the prevailing industry view of government is not quite that harsh, and yet one cannot deny that government intervention is indeed pressing in on the mineral industry with increasing force. What is happening today in Washington and in state capitols will have enormous impact--both short and long term--on the future of coal and mineral production in the United States. Symptoms of this trend are everywhere. In the first place, there is a sentiment, widely held and still spreading, that the government must become involved-- that no matter what the problem, the solution lies in more government intervention. Free enterprise versus statist, reflex reaction organizations. When it cones to regulation in the resource field, there is too often a tendency to start out by assuming guilt on the part of the mineral industry. This can lead to laws governing mineral recovery that are more punitive than constructive...laws drawn up with little research into the scientific or economic considerations involved.

Jan 1, 1975