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By S. Z. Khan, Veerendra Singh, Y. Rama Murthy, S. Prasad, Sunil Kumar Tripathy, Gajanan Kapure

"In this study, a low-grade ferruginous low-grade chromite ore was subjected to reduction roasting by using conventional heating as well as microwave heating. Sukinda chromite ore deposit contains majorly iron-bearing minerals as gangue phase. The magnetic susceptibility of these minerals enhances effectively after reduction roasting. Alteration of crystalline structure and magnetic property of these metals enables separation of low-grade ore by using magnetic separation. Conventional roasting studies by varying the temperature, time of reduction and reductant dosage were changed for low-grade ferruginous chromite ore. Similarly, microwave power, retention/exposure time and reductant dosage varied for reduction roasting studies under microwave environment. It is found that low-grade ferruginous chromite ore can be upgraded by reduction roasting and 61.2% Cr2O3 was recovered with a chromium-to-iron ratio of 1.93 from feed chromium-to-iron ratio of 1. Microwave reduction roasting studies resulted in upgradation of chromium-to-iron ratio to 1.73 with a recovery of 21% Cr2O3.INTRODUCTION The chromite ore occurs as a spinel containing oxides of chromium, iron, magnesium and aluminium. Most of the Indian chromite deposits are of ferruginous (rich in iron content) which indicates the abundance of ferruginous gangue minerals along with chromite. The primary use of chromite ore is towards the production of ferrochrome alloys. Chromite ores with less than 40% Cr2O3 and the chromium-to-iron ratio (Cr-to-Fe ratio) <1.8 is considered to be unsuitable for the smelting process (Tripathy et al. 2012, Tripathy et al. 2012a). A considerable amount of low-grade chromite ore and overburden excavated during chromite mining is getting accumulated every year, causing a threat to the environment. Its disposal poses a significant challenge and, hence, the beneficiation of low-grade chromite ore and its utilisation has been attracting a lot of attention. Different physical method of beneficiation methods is generally employed for the improvement of the Cr-to-Fe ratio (Tripathy et al. 2012, Murthy et al. 2011, Tripathy et al. 2012a, Tripathy et al. 2013, Tripathy et al. 2016, Tripathy et al. 2017, Tripathy et al. 2017a). It is observed that the enrichment of the chromite ore is carried out by using gravity and in some places by magnetic separation. However, the enrichment of Cr-to-Fe ratio from low-grade ferruginous chromite ore is difficult by using the above-mentioned beneficiation methods due to the presence of near gravity and near-magnetic susceptibility minerals along with chromite. However, an alternative beneficiation method is needed to explore for the beneficiation of such mineral deposits. Reduction roasting followed by magnetic separation is an alternative option for the separation of these types of ores which is widely reported for the iron and manganese ore (Li, et al., 2010; Chun, et al., 2014, Rath et al., 2018). These processes are majorly focussed on differentiating the magnetic susceptibility between minerals and subsequent separation by using magnetic field. The main advantage of such method is dry process option along with the pre-processed product for the costly smelting process. Also, the roasting of minerals in a microwave environment is also an active research topic in the recent time. So, the amenability of the separation feature of the roasting process by using conventional heating as well as microwave heating can be can be studied for the low grade ferruginous chromite ores."

Jan 1, 2018

By M. F. Dunn

The objective of this work was to define jet fan performance in d variety of large cross-section underground mine applications and to develop guidelines for thin performance in open airways, dead headings, and multiple face areas. Measurements include common ventilation instruments, continuous recording remote electronic anemometers to measure air velocity, and sulfur hexaflouride tracer gas with chromatograph analysis to determine dilution rates and air recirculation. For open airways the following were determined: Large jet fans are leas efficient in smaller airways, but quite effective in larger open airways for achieving both uniformity end greater air entrainment, when inclined about 10° or elevated. For dead headings the following were determined: The jet fan must be placed against the rib of the heeding closest to the incoming airstream from the crosscut or recirculation will increase. The fan should be placed at the pillar corner to increase airflow. As the fan is moved closer inby, recirculation increases. Larger fans promote recirculation. Inclining fans about 12° improves airflow in large headings. For face areas the following were found: For panels having uncontrolled airflow, the fan should be placed in the incoming airflow, about one pillar inby, and directed diagonally across the faces. For panels having narrower rooms and controlled airflow, the fan should be placed alongside the panel side in the first room so as to direct or intersect the incoming airflow at the next entry or crosscut.

Jan 1, 1983

By D. Parks, A. Miller, M. McNinch, R. Jacksha, H. Nickerson

Each year hundreds of mine workers are involved in machinery-related accidents. Many of these accidents involve inadequate or improper use of lockout/tagout (LOTO) procedures. To mitigate the occurrence of these accidents, new safety methods are needed to monitor access to hazardous areas around operating machinery, improve documentation/monitoring of maintenance that requires shutdown of the machinery, and prevent unexpected startup or movement during machine maintenance activities. The National Institute for Occupational Safety and Health (NIOSH) is currently researching the application of Internet of Things (IoT) technologies to provide intelligent machine monitoring as part of a comprehensive LOTO program. This paper introduces NIOSH’s implementation of an IoT-based intelligent machine monitoring system to improve safety during operation and maintenance at a concrete batch plant. INTRODUCTION Of the hundreds of machinery-related accidents occurring every year in the mining industry, incidents involving stationary machinery at surface mines continue to be amongst the most frequent [1]. A National Institute for Occupational Safety and Health (NIOSH) study showed that the majority of fatal accidents involving stationary machinery at surface mines occurred at sand and gravel (38%) and stone (26%) operations. Of these accidents, entanglement in conveyor components were the most common cause of fatal accidents (48%) [2]. The same study stated that one-third of these accidents involved improper lockout/tagout (LOTO) procedures as a contributing factor. The U.S. Mine Safety and Health Administration (MSHA) acknowledged this problem, stating in a recent request for information (RFI) [3]: “Since 2007, there have been 17 fatalities related to working near or around belt conveyors, of which 76 percent were related to miners becoming entangled in belt drives, belt rollers, and discharge points. Factors that contribute to entanglement hazards include inadequate or missing guards, inadequate or an insufficient number of crossovers in strategic locations, and/or inappropriate lock out/tag out procedures. Systems that can sense a miner's presence in hazardous locations; ensure that machine guards are properly secured in place; and/or ensure machines are properly locked out and tagged out during maintenance would reduce fatalities [3].” In response to this problem, NIOSH’s Spokane Mining Research Division (SMRD) is exploring the potential application of Internet of Things (IoT) technologies to provide cost-effective intelligent machine monitoring systems for improved worker safety [4, 5]. SMRD partnered with Central Pre-mix CRH Company (Central Pre-mix) to develop and install a proof-of-concept wireless IoT solution to monitor machinery and conveyors during operation and maintenance. The primary goals of the system were to provide real-time monitoring of access points and facilitate the planning and execution of LOTO procedures

Jan 1, 2019

By Partridge AC

The measurement of particle size is very important in many industries. Comments in this paper refer principally to the Mineral Industry and in particular to Coal Mining and Coal Preparation. The objective is to indicate the importance of particle size in process design and process assessment and to describe techniques for particle size measurement and the presentation of results.

Jan 1, 1984

By P. Burke, V. Vuaroqueaux, A. Doyle, C. Petit, Kipouros. G. J.

Magnesium and its alloys are attractive for use in automotive and aerospace applications because of their low density and good mechanical properties. However, difficulty in forming magnesium and the limited number of available commercial alloys limit their use. The present work reviews the efforts to improve the attractiveness of magnesium through non-traditional processing, and presents results of current work on producing magnesium alloys via powder metallurgy (P/M). P/M can be used to alleviate the formability problem through near-net-shape processing, and also allows unique chemical compositions that can lead to new alloys with novel properties. The surface layer formed on the Mg powders during processing acts as a barrier to diffusion and sintering is problematic. The layer contains oxides, hydroxides and carbonates of magnesium, formed by reactions with the atmosphere. There are several means to possibly overcome this barrier. Alloying additions have been identified that may promote surface layer disruption during sintering. Processing variables such as sintering atmosphere may reduce the layer or allow the formation of less detrimental compounds. Post-sintering processes such as hot working may disrupt the layer and improve density. The experimental effect of all these processing parameters is presented in this paper.

Jan 1, 2010

By James J. Holmes

ACCIDENT prevention as we know and understand it today is of comparatively recent origin. As a matter of fact, the Industrial Accident Prevention Association of Ontario, which is the oldest organization of its kind in the Dominion, celebrated its thirtieth anniversary only this year. On the other hand, one could say that the history of accident prevention is almost the history of mankind itself. In a general sense, every forward step that man has made throughout the centuries has been largely due to two things: (1) a desire for increased comfort, and (2) the need for safety; and, always, the need for safety has taken precedence over the desire for comfort. While it is true that hundreds of volumes have been published, dealing with the many aspects of accident prevention work, you cannot go to a library and pick out a book that has all the answers in it. Such a book has never been published-we are still looking for some of the answers. However, a good deal of real progress has been made.

Jan 1, 1945

By William R. Bond

The pressure/vacuum lysimeter is being used as an effective vadose zone monitoring device for mining heap leach facilities, tailing disposal ponds and tailing waste sites. Their use has proven reliable for baseline data collection, early warning leakage detection and analyzing geochemical variations in the vadose zone. The lysimeter structure utilizes a closed cylindrical chamber made of PVC or inert material. The soil water intake portion of the cylinder is made of a porous material of low permeability. The application of vacuum or pressure to the unit is via two access tubes from the ground surface. Available soil moisture is drawn by vacuum through porous material into the lysimeter chamber and then collected from the access tubes. Case studies show their usefulness for monitoring around a uranium tailing pond constructed in glacial till material, under heap leach pads and pregnant, barren, and overflow ponds, and investigating the movement of contaminant moisture through old tailing deposits. Relatively easy to install and sample, regulatory agencies and facility operators are accepting and negotiating for their application as a site integrity monitoring device and unsaturated zone research tool. Their use at heap leach facilities lends credibility to solution balance calculations when considering a leachate loss of 5 or 10 percent can make or break a mine&apos;s profitability.

Jan 1, 1984

By Arkady Senchenko

The paper deals with the problem of refractory gold-containing material processing. It is observed that all traditional methods for liberation of fine gold from this type of products are characterized by a number of essential disadvantages, where the main ones are ? considerable expenses for ore processing and big environmental impact. As an alternative to the existing methods there is considered a gold liberation method, which is based on the combination of ultra fine grinding process with the consequent atmospheric oxidation. The theoretical justification of atmospheric oxidation was carried out, in the result of this the mechanism and the degree of sulphide minerals? oxidation was found out, the dependence of gold dissolution speed on the slurry content in liquid phase produced by grinding and oxidation was identified. The experimental data and results of pilot-plant testing are given and the most effective grinding and atmospheric oxidation mode is selected on this basis. The performed complex of research works allowed us to use the provided technology at the gold processing plant having capacity of 8 mln. tons of ore per year. The questions, problems, advantages and disadvantages of atmospheric oxidation technology for refractory gold-containing concentrates are considered in this paper. Keywords: refractory gold-containing material processing, gold liberation method, cyanidation

Sep 1, 2012

By I. Soto, E. Córdova, A. Anani

The new caving megaprojects that are planned to go into production in the next decade have scheduled horizontal developments at very high rates, which are difficult to achieve. Research has been conducted that seeks to model the construction times for underground developments to determine the feasibility of achieving the planned rates. However, these previous attempts do not consider all the operational aspects that make up the mine development cycle. Here, we present a discrete event simulation (DES) model that individualizes each unit operation of the development cycle to determine the construction rates that new projects will be able to attain. The developed model was applied to the New Mine Level (NML) of the El Teniente Division (DET). The results indicate that it would be impractical to achieve the advance rates scheduled in the original plans if the unit operations of the mine continue to be executed using the status quo. The metres developed after six years in the sections analysed can be significantly improved by changing the maintenance strategy for the equipment (457 metres increase), orepass availability (194 metres increase), and the initial planning sequence (1 598 metres increase). It is recommended that the mine implements a flexible maintenance strategy, defines a strategy to ensure and increase orepass availability to contractors, and makes use of current simulation tools for a more robust development sequence planning.

Oct 1, 2022

By Wilson AC

Permian coal from Western Australia&apos;s only producing coalfield at Collie is the dominant fuel used in generating electricity for the State&apos;s interconnected grid. Collie coal is sub-bituminous, non-coking and has a low ash, medium volatiles and high moisture content. The seams were laid down in a fluvial basin which extended beyond the Collie Basin and included the Wilga and Boyup Brook Basins at least. Adjacent parts of the southwest Yilgarn Block are prospective for Collie-type basins. In the past few years significant deposits have been delineated within the Perth Basin, specifically on the Vasse Shelf and in the Hill River area. In the former area high quality steaming coals are correlated with the lowest coal bearing member at Collie. The seams are amenable to underground mining and because of their high quality, the coal may have export potential. Sub-bituminous coal deposits of Jurassic age are present in the Hill River area. Exploration has down-graded the prospectivity of the Carnarvon and Canning Basins for sub-bituminous near-surface coal deposits. Tertiary lignite deposits are present in palaeo-drainage systems in the southern part of the State and their potential for development is being evaluated.

Jan 1, 1986

By J. Paturaud, A. G. Villemiane, J. Y. Buffiere, D. Fabregue, M. Perrier

In this work, a detailed characterization of the cyclic damage mechanisms on duty in car heat exchangers has been carried out in order to improve their reliability. The material which consists in very thin (<0.3 mm thick) sheets formed of 3 co-rolled aluminum alloys (4045 /3916/ 4045) has been brazed in order to obtain metallurgical and surface conditions representative of those of the real components. Fatigue tests at constant stress amplitude have been performed at room temperature and 120°C in order i) to characterize the cyclic resistance of the studied materials and ii) to study the effect of temperature on the fatigue damage mechanism. The mechanisms leading to failure have been identified from post mortem fractographic analysis. The Wohler curves obtained show that, contrary to common structural Al alloys, this type of thin sheet brazed multi material can be cycled for several hundred thousand cycles at very high stress level (> ~ 80 % of the tensile strength). This behaviour is analysed with respect to the microstructure resulting from the brazing process and the low number of grains present in the sample thickness (around 5 grains).

Jan 1, 2015

By Peter G. Chamberlain

Domestic mining will not produce a significant portion of the manganese consumed in the United States unless new mining and processing techniques are implemented that will enable domestic lean ores to economically compete with rich foreign ores. One mining-processing technique that appears promising for certain deposits is in situ and/or heap leaching with aqueous SO2. Since leaching offers economic advantages of low capital costs, low operating costs, and short start-up times as well as environmental and safety improvements over conventional mining-processing, the Bureau of Mines studied the leachability of manganese deposits from several districts. Manganese oxides, hydroxides, and carbonates were leached to 80 to 90 pct recovery in 7 to 40 days of leaching with a solution containing 5 pct SO2 in column leaching tests. Preliminary cost analyses of surface mining-heap leaching, block caving-in situ leaching, and shrinkage stoping-in situ leaching indicate that the products of manganese leaching may be economically produced for the chemical and electrolytic manganese industries. The easiest marketable product to obtain would be a manganese sulfate commonly used as a fertilizer amendment. Manganese carbonates and hydroxides could also be precipitated from the pregnant leach solutions.

Jan 1, 1983

By R. Fukuzawa

"The objective of this research is to evaluate the magnitude of carbon prices required to drive process development and innovation for the global nickel industry in a direction that tackles the multifaceted sustainability challenges that the industry faces, including air pollution reduction and greenhouse gas abatement. The results suggest that the currently considered carbon prices are not sufficient to drive innovations in processing methods or upstream pollution prevention. The co-benefits of climate change mitigation and pollution prevention cannot be readily realized under climate change policy alone. Increased coordination between climate change policy and performance-based environmental legislation is necessary. INTRODUCTIONNickel is an important metal in our modern society as it is used in stainless steel, alloys, electroplating and rechargeable batteries, all of which are integral to our economic growth and development (Eckelman, 2010).However, nickel production is energy intensive and therefore susceptible to emerging climate change policies, which may lead to production curtailment and/or increased unit costs of production unless changes in efficiency or energy sources are made (Mudd, 2010). The industry is faced with multi-faceted constraints: future technology must not only deal with metallurgical, financial and environmental constraints but also promote low energy and low carbon practices. This presents a challenge for this industry where technology innovation, development and commercialization are often lengthy, risky and costly processes (Imrie, 2006).Climate change is one of the many challenges faced by our society. Others include other pollution to air, water and land, resources shortage and economic development. From a policy perspective, it is important to balance multiple and often competing needs in an integrated manner. It would require some levels of trade-off in order to maximize the overall effectiveness but also to ensure that one policy does not undermine other policy objectives.The aims of this study are to evaluate how developments in climate change policy would affect the nickel industry in the context of existing environmental regulations and how the industry could respond under these constraints."

Jan 1, 2012

By F. L. Wideman

This paper lists resources of sulfur in Wyoming, Colorado, Utah, New Mexico, and Arizons, an area comprising approximately 522,600 square miles, Sources of sulfur occuring within the region are sulfur are, pyrite and pyritic ores, and natural gases and petroleum. Data concerning these sources are presented on a statewide basis. Some of the known deposits of sulfur ore are surficial and of fumerole origin; other deposits have resulted from oxidation of pyrite or sulfide ores of copper, lead, and zinc. The deposits are small and the sulfur is distributed erratically in them. There is a small production from some of the deposits, and the material produced is used as soil conditioner.

Jan 1, 1957

By S. Lun Sin

In this study, the effect of silicon on the microstructure, mechanical properties and hot tearing susceptibility of permanent mould cast AZ91E magnesium alloy was investigated. Varying amounts of silicon (0.5, 1.0 and 1.5 wt.%) were added to AZ91E in the form of an Al-53 wt.% Si master alloy. The phase formation, grain size and solidification behavior of each alloy were characterized and related to their tensile properties and hot tearing susceptibility. The results showed that the addition of silicon resulted in the formation of Mg2Si particles. The presence of these particles led to an increase of the hardness, but was detrimental to the tensile strength and elongation of AZ91E. However, silicon significantly reduced the hot tearing susceptibility of AZ91E. This was attributed to the reduction of the grain size and the decreased freezing range of AZ91E, which contributed to improve the interdendritic feeding during the last stage of solidification.

Jan 1, 2011

By G. A. Smyres

A GaC12--B2 l-eachtng procedure and meEal-recovery method for treating an arsenical Cu-Co sulfide concentrate was developed by the Bureau of Mines as an alternative to smelting, which is no longer considered an environmentally acceptable method for treating arsenic-containing ores. The procedure involved leaching in a CaC12 solution with CaC03 for 96 h at 26 pct solids (concentrate and CaC03), 1150 C, and a pressure of 50 psig (345 kPa) with oxygen. More than 98 pct of the cobalt and 97 pct of the copper were extracted, and 99.98 pct of the arsenic and 99.9 pct of the iron remained in the leached residue. A filtration rate of 2.9 gal/(ft2.h) [118 L/(m2.h)] and a cake formation rate of 36 Ib/(ft2.h) [172 kg/(m2.h)] were obtained by filtering reacted pulp at 1000 C. More than 99 pct of the copper in the pregnant solution was extracted as CuCl2 by golvent extraction with a new copper extractant. Copper was stripped from the loaded organic with a sulfate-chloride solution, which was used as the anolyte for electrowinning of copper in a membrane cell. Copper plate produced was more than 99.99 pct pure and requi.red 0.81 (kW&apos;h)/lb Cu [1.78 (kW·h)/kg Cu]. Cobalt sulfide was precipitated at pH 3 with Ca(HS)2.

Jan 1, 1986

By P. A. Surgeon, R. R. Sayers

It is not the purpose of this report to try to describe all the work done during the past year for the improvement of health or the prevention of illness among miners , but to call attention to a few of the more outstanding investigations in which progress has been made . Among these , the investigations on the physiological effects of carbon monoxide , dust and ventilation , and temperature and humidity will be discussed . Carbon Monoxide . During the years 1920 and 1921 , much more work has been done on the various A survey phases of carbon monoxide than has been carried on for a number of years . of carbon monoxide poisoning in the American steel works , metal mines , and coal He conmines was made by Dr. Henry S. Forbes , of the Harvard Medical School . ** cludes from his survey that late after- symptoms following acute severe gassing rarely occur , and that almost always there is evidence of pre - existing pathological conditions when such effects do appear . He further states that he found no evidence of cumulative harmful effects resulting from frequent exposure . Dr. Forbes , Dr. Forbes , assisted by Louise Hompe , made a laboratory investigation in which anesthetized animals were exposed to carbon monoxide , illuminating gas , and benzol *** . The investigators conclude that , under the conditions of their experiments , there is no change in the coagulation time of the blood . It has been stated by many investigators that the blood of those affected by carbon monoxide does not clot as quickly as normal blood . While the investigation referred to above may not cover all the conditions , it is a valuable contribution to the subject as it indicates that the small hemorrhages found in the membranes covering the central nervous system , abdominal organs , etc. , at autopsy of those dying of carbon monoxide poisoning is probably not due to direct toxic action of the gas upon the blood .

Feb 1, 1922

By Douglas A. Elkins

The unique characteristics of plasmas, their current applications, and ongoing research into new applications are described. Major technical and economic problems in application of plasma technology are discussed. Examples of potential applications of plasma in extractive metallurgy are described and evaluated. The report includes a selected bibliography of articles on plasma and related high-temperature technology.

Jan 1, 1969

By Shirley F. Colby

A continued rise in construction activity in 1941 forecasts further increases in the demand for building materials of mineral origin, Recent studies by the Bureau of Mines, United States Department of the Interior, reveal that sales of mine and quarry products and their derivatives as a class have followed the long-term trend of construction activity in the past and are benefiting now by the upswing in all types of building. At present most building materials of mineral origin are holding their own in the competitive arena. A few are slipping behind, but others have forged fax ahead. Prominent among those that have surpassed general construction activity since 1925 are sand, gravel, and crushed stone (used in concrete and road metal and railroad ballast) and cement. Both building stone and roofing slate have followed the building curve closely, although in the last few years sales of roofing slate have risen above the curve and sales of building stone have dropped below it. Clay products and building lime, on the other hand, have lagged behind the general procession. Gypsum sales likewise dropped behind, but during the last few years, this industry, thanks to the wider acceptance of its newer products, has staged a marked recovery so that it now stands in about the same relation to total construction activity as it did is 1927-25.

Jan 1, 1941

By Arnold P. Szaj

There is no startling revelation to the fact that the mining industry as a whole is generally moving toward the use of larger equipment to process ores in quantities far greater than what was even considered a decade ago. Trucks and shovels have led the way in extra large machines and many other manufacturers have followed suit in the development of so-called "supers" in their line of equipment. In order to keep pace with the industry, crusher manufacturers have also enlarged the size of their equipment. There is now on the market, a Gyratory crusher capable of accepting a 72" diameter piece of ore. Primary jaw crushers have also increased in size. It is inevitable, therefore, that larger secondary cone crushers would also be required to complement the other equipment used to process these large quantities of ore. This super-size secondary cone crusher is the SYMONS 10 Ft. Cone Crusher. Until 1973, the largest cone crusher built was the 7 Ft. Extra Heavy Duty crusher, which is currently used in the majority of the mining operations throughout the world. The 10 Ft. crusher, when compared to the 7 Ft. Extra Heavy Duty Crusher, is approximately 1-1/2 times larger in physical dimensions; three times heavier; will accept a maximum feed size which is approximately twice as large; and will crush at approximately 2-1/4 times the rate of the 7 Ft. machine at identical closed side settings. It will be the largest cone crusher built in the world. At the present time, Rexnord&apos;s Nordberg Machinery Group has accepted an order for two 10 Ft. Standard cone crushers to be delivered to an iron ore mine in South Africa in early 1975.

Jan 1, 1973