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By Kathryn Hindmarsh

The most common method for the concentration of cyanide in gold leach circuits is based on the titration of cyanide ions with silver ions. This can either be done manually as a titration with a visual end-point or by using one of several commercial cyanide analysers which are 'based on the same titration but use a potentiometric end point This method has 'its limitations in the case of some ores such as those containing high amounts of soluble copper and those that are treated at low (less than pH 9) pH values in that the titration results do not accurately reflect the concentration of cyanide which is available for the dissolution of gold. This paper will present the results of the development of a novel "active" cyanide analyser which is based on the rate, of the reaction between gold colloids and cyanide. Gold colloids have a deep red colour and can be very simply prepared and stored for extended periods of time when stabilized. t has been shown that colloidal gold behaves similarly to metallic gold, dissolving in aerated sodium cyanide solutions to give the colourless Au(CNh-ion, This allows the reaction between the colloids and cyanide to be monitored spectrophotometrically at 520 nm. An automated instrument has been developed around this concept which can analyse a filtered pulp stream every few minutes with periodic calibration using standard cyanide solutions, Results of test work on synthetic solutions and solutions derived from several Australian gold plants will be presented as will the results of a comparative evaluation with a commercial titration analyser on a local gold plant

Jan 1, 1998

By G. H. Cutter

SAFETY in mining depends on wire rope to as great, if not greater, extent than in any other industry. Sudden failure of a shaft-hoist rope might easily result in death or serious injury to the operators and workmen, extensive damage to expensive equipment, and a loss in production while repairs are being made. A wire rope is only as good as its component parts. It must be made from wire properly drawn and treated. It must be fabricated on machines large enough and capable of imparting the necessary qualities to meet the stringent service conditions. However, unless the fundamental requirement of good ropemaking is recognized, all other operations, no matter how carefully performed, will not impart reliability and quality to the product. This fundamental requirement is steel that is homogeneous, of high resistance to fatigue, and of a type suitable for rope wire. Most wire-rope manufacturers agree that rope wire should be made from acid-open-hearth steel. It is comparatively easy to meet the same physical properties with basic steel, but such properties are only part of the requirements for good wire. It is absolutely necessary, particularly for rope service such as mining, where reliability is essential, that the wire be uniform throughout its entire length. Most manufacturers feel that this highly important requirement is better met by acid-open-hearth steel.

Jan 1, 1936

By Robert S. Archer

THE proper material of construction for a given purpose is that material which meets the requirements satisfactorily at the lowest ultirnatc cost. It is consistent with this principle that most aluminum castings are made of an alloy containing about 8 per cent. copper. This alloy possesses mechanical properties satisfactory for general engineering purposes together with manufacturing characteristics leading to the production of finished castings at low cost. It is to the aluminum industry what gray iron is to the iron and steel industry. Just as some services require "semi-steel," malleable castings or steel castings instead of gray iron, there is a certain and growing demand for aluminum castings of superior strength or ductility, or both. Since the beginning of .the industry producers and others have sought to develop alloys or processes by which such castings could be made. Out of these efforts have emerged many alloy compositions and special processes, of which only a few have had sufficient merit to survive. It is the purpose of this paper to describe those which seem to the authors to offer the greatest promise for the production on a commercial scale of aluminum castings of superior mechanical properties, with special reference to heat-treated castings. The suitability of an alloy or process for actual manufacture is affected by so many factors that the problem of appraisal is not a simple one. Since this is such an important part of the whole subject it is proposed to discuss briefly some of the requirements. The final verdict is of course the result of commercial trial and experience. It will therefore, perhaps, be profitable to employ a somewhat historical method of treatment in discussing the subject of alloy development. The alloys or processes to be used in the production of aluminum castings are to be considered from the standpoint of their effects on both the utility and the cost of the finished casting. Specific gravity and mechanical properties come under the first head, while the properties

Jan 1, 1927

By Paloma Lazaro, Moe Momayez

Heat-related illnesses (HRI) are relatively common in both hot surface and underground mining operations. When workers are exposed to extreme heat or strenuous work in a hot environment, they become prone to heat stress. Heat strain is the result of the body’s response to external and internal heat stress. It is therefore vital for the conditions leading to heat strain be detected and treated in a timely manner. Heat-related illnesses are manifested by exhaustion and heat stroke. The predicted heat strain (PHS) [ISO 7933 (2004)] model has been developed to predict the health condition of the worker in terms of core body temperature and water loss. The PHS model tested in this study is based on eight physical parameters that are measured at different intervals during a work shift. They include air temperature, humidity, radiation, air velocity, metabolic rate, clothing insulation, posture, and acclimatization. The model predictions are then compared with a direct physiological measurement, such as core body temperature. We present the results of an extensive study that monitored and predicted body’s response to heat stress under different environmental and working conditions. The PHS model provided reliable results in most instances in comparison with other prediction methods currently in use in the field.

By Paloma Lazaro, Moe Momayez

Heat-related illnesses (HRI) are relatively common in both hot surface and underground mining operations. When workers are exposed to extreme heat or strenuous work in a hot environment, they become prone to heat stress. Heat strain is the result of the body’s response to external and internal heat stress. It is therefore vital for the conditions leading to heat strain be detected and treated in a timely manner. Heat-related illnesses are manifested by exhaustion and heat stroke. The predicted heat strain (PHS) [ISO 7933 (2004)] model has been developed to predict the health condition of the worker in terms of core body temperature and water loss. The PHS model tested in this study is based on eight physical parameters that are measured at different intervals during a work shift. They include air temperature, humidity, radiation, air velocity, metabolic rate, clothing insulation, posture, and acclimatization. The model predictions are then compared with a direct physiological measurement, such as core body temperature. We present the results of an extensive study that monitored and predicted body’s response to heat stress under different environmental and working conditions. The PHS model provided reliable results in most instances in comparison with other prediction methods currently in use in the field.

By John D. Spencer

Projects aimed at achieving the least disturbance to the Nation's air, water, and land resources in the mining and utilization of coal continued to be a feature of the Bureau of Mines coal program. This reflects the current concern about damage inflicted on the environment by our growing and increasingly affluent society. Mine Health and Safety research, along with investigations related to all other aspects of coal extraction and use, also continued to be implemented and expanded.

Jan 1, 1970

By W. S. Landers

This bulletin is a detailed study of low-temperature, entrained-bed carbonization of a Texas lignite. The lignite studied was from the Sandow strip mine and is representative of the Rockdale formation of the Wilcox formational group. Carbonization was conducted in a continuous entrained-bed reactor at several temperatures in the 8801 to 1,52°C F range, and at air-coal ratios it the 0 to 10.30 scf/lb range (moisture- and ash-free basis). Carbonization rates ranged from 97.1 to 410.0 lb/hr (as-received basis), At the higher air-to-coal ratios employed, all or most of the carbonization heat was provided by internal combustion with air in the reactor. At the lower air-to-coal ratios, parts of the heat for carbonization was supplied externally. It was demonstrated that the entrained-bed carbonization of lignite is a complex reaction and that several variables, of which carbonization temperature, air-to-lignite ratio, and the average size of lignite are important, act together to influence both the carbonization yields and the properties of the resultant products, Process variables established by pant tests were used to design the industrial scale carbonizer operated at Rockdale, Texas, by the Texas Power & Light Company as agents for the Aluminum Company of America. Properties of the carbonization product obtained from the industrial scale reactor were essentially the same as those obtained from the pilot plant reactor operated under the same conditions.

Jan 1, 1968

By GERALD H. HUTTON

SINCE the inception of dredge mining, the attention of engineers and operators has been directed primarily toward mechanical improvements and refinements calculated to, reduce operating costs and to increase recoveries. The result has been to develop an efficient excavating and value-saving machine, which, in some instances, has an actual capacity of 15,000 cu yd. per day. Steel hulls and superstructures minimize the risk of destruction by fire and lengthen the life of the plant. Dredges now restore, to some extent, agricultural possibilities to mined ground. Large buckets, with correspondingly heavy parts, are able to handle heavy wash and massive boulders. Mechanical weaknesses have been strengthened. The use of manganese steel in bucket lines and tumblers permits the application too the bank of a digging force that can be withstood only by solid material, such as rock, cement or frozen ground. Various alloys of steel have been applied to certain duties and experiments in their heat treatment are still progressing. Haulage by tractor or truck is in common use. Discarded and worn steel parts are repaired or rebuilt by the use of the oxy-acetylene flame and the arc-welding machine. Gold and platinum saving is more efficient, although still subject to improvement. Dredging for tin ore is in successful operation. Crews are now highly specialized and experience has developed improved methods of work; particularly in the manipulation of dredges to build levees of tailings and to leave open waterways where desired. To sum up by the distribution of overhead expense over several units, ground under favorable conditions can now be dredge-mined for 5)2 c. per cu: yd., in spite of the increase in cost of supplies, power, and labor during, the past few years. Improvements in prospecting methods, however, have not kept pace with mechanical developments. Standard practices of ; testing ground today produce only wide approximations of values; although they obtain information concerning the character of the deposit and bedrock. It is interesting to note that few important changes in the methods of ten years ago are .to be recorded; the latest comparisons between pros¬pecting results and mined recoveries-have been at such variance as to cause confusion to the operator, and, in a degree, the sacrifice of the confidence of the capitalist. On this account, and because the growing scarcity of dredging ground. demands closer calculations on the part of the engineer, this appeal for collaboration and

Jan 1, 1921

By Victor Azbe

Azbe System of Controlled Calcination To obtain good and cheap lime there are certain fundamental requirements that need to be satisfied. These are : (1) Proper combustion of fuel and steady supply of heat to the kiln. (2) Proper heat distribution in the kiln. (3) Uniform drawing of lime through the several shaft sections. (4) Complete cooling of the lime and recovery of the heat. (5) Temperature control of the hot zone by economical means. (6) Ample draft to obtain high capacity. (7) Arrangements to facilitate operation. Figure 17 shows diagrammatically one of the smaller kilns, intended for large stone. Such a kiln can be supplied with gas from a centrally located automatic gas producer, or, as shown, from an integral producer located snugly against the kiln. These producers make very good gas and have a gasification capacity of either 10 or 15 tons of coal a day. The producers have water-sealed ash pits, a rather thick fuel bed that is conducive to the making of high-CO gas, and are under forced draft. No steam is used. Clinkering is prevented by admixing some spent gas from the kiln with the air. Coal feeding is from a coal bunker through spouts into the hoppers over the producer. This is done, at proper intervals, by manual operation of slides, but it is planned to install mechanical feeders. Central mechanical gas producers have the advantage of requiring little labour, but the blowing of soot is a problem, as also is the proper distribution of the gas among several kilns. In the case of integral gas producers, soot from the centre burner is blown back into the producer to be burned, and the supply of gas to the kiln is controlled by regulation of air to the producer. In large plants, the mechanical producer may be preferable, but in small ones, the integral producer is cheaper, better, and more reliable. The kiln shown in Figure 17 is suitable for both systems of gas supply. It will be noticed that there are no side gas burners. All gas enters the kiln through the centre burner in a manner that permits any desired amount of gas to be directed to any of the kiln sections by the aid of regulating slides.

Jan 1, 1946

Operator efficiency and control capability along with cost effectiveness have been the quest of mining, industrial, and mobile hydraulic engineers for years. The majority of the functions in present day fluid power systems are controlled by on/off control valves. They are inexpensive and provide easy installation and operation, but they lack the quality of fine control of load flow or what is sometimes known as "feathering the load". An alternate approach to obtaining this capability is the use of electro-hydraulic servo-valves, but their implementation into a system is complex, and they are expensive. As a result, electrohydraulic systems are still used primarily in the aerospace industry. Of late, a compromise seems to have evolved between the on/ off control systems and the servo-technology is the so-called proportional flow control valves. A proportional flow control valve meters fluid to the load in proportion to the input command from the operator. In principle, it is similar to a conventional flow control valve and is tailored to meet the control requirements from the load point of view. The hydraulic system using this valve usually works in an open-loop mode with the operator closing the loop. Incorporating load-sensing mechanisms and adoption of electrical/electronic signalling into the valve make it the "ideal valve" which designers have been looking for from a techno-economic point of view.

Jan 1, 1983

By G. B. Shea, R. A. Cattell

This resume of the work of the Petroleum and Natural - Gas Division of the Bureau of Mines for the fiscal years 1940 and 1941 is the second of a series. of progress reports . It brings forward from the 1939 annual report information on the course of activities of the division in carrying out its objectives of increased conservation and better utilization of petroleum, natural gas, and related resources through a coordinated program of research and fact - finding . It discusses, also, special assignments. executed for other Government agencies, which in recent years have constituted a considerable part of the division's work ." . In the present national emergency, in which petroleum is so essential , many of the Bureau's research activities bear directly on the availability, conservation, and use of petroleum for national defense . Accordingly, during the past year attention has been focused for the most part.on.problems associated with the needs of national defense . Several long-time researches , which in themselves are potential sources of desirable knowledge , were judged to be of secondary importance under present conditions and accordingly were suspended . Studies also were oriented in line with rapidly changing conditions to meet the demand for accurate findings on short notice . The Petroleum and Natural - Gas Division has experiment stations at Bartlesville , Okla . , and Laramie, Wyo . , a field office at Dallas , Tex . , and a field office and laboratory at San Francisco , Calif . It also operates the Government helium plant near Amarillo , Tex. In addition to the helium operations , some of the petroleum and natural - gas research activities are conducted at the Amarillo plant .

Feb 1, 1942

By Mark Davis

As a follow-on to previous investigations, reduced treatment levels for the optimum fire retardant/preservative system were evaluated. An impregnation of 3.5 lbs/ft3 of Fyreprufe followed by 3.5 mils of Albi 107A plus an Albi 144 top coat provides adequate flammability and flame spread protection. However, there is a significant loss in compressive strength at this retention level, particularly parallel to the grain. A pilot-size pressure impregnation cell was installed for use in treating larger quantities of wood. Based on the optimum fire retardant/preservative treatment system - Fyreprufe/ACC impregnation followed by Albi 107A/144 intumescent paint - a model treatment pro¬cess was developed, capable of handling 3 million board feet per year. Associated annualized costs per thousand board feet (K bd. ft.) for treating 12" x 12" timber were calculated to be: Impregnation: $-63.00/K bd. ft. Coating: $112.00/K bd. ft. A literature search was conducted to identify materials and techniques suitable for a localized stench warning system for heated mine timbers. Based on this review, a number of stench warning concepts were developed. Those based on surface coating were given a preliminary laboratory evaluation.

Jan 1, 1982

By Lidong Teng

ArcSaveTM is a new generation of electromagnetic stirrer (EMS) from ABB for electric arc furnace (EAF) operation. Its goal is to improve the safety, increase the productivity and reduce costs. Electromagnetic stirring in the melt bath during arc furnace operation will affect the scrap smelting, bath temperature distribution, refining reactions, and also the tapping practice. This paper has summarized the investigation results obtained from the first ArcSaveTM system installed in a 90 ton EBT arc furnace in USA. The hot test results show that ArcSaveTM has enhanced the heat and mass transfer in the arc furnace process. This results in a faster scrap melting rate, lower slag superheat during arcing, more homogenous melt bath, higher decarburization rate and higher EBT free opening frequency. ArcSaveTM has also reduced the tapping temperature and tapping oxygen in the steel. This brings a higher scrap yield and saves ferroalloy consumption in the downstream ladle furnace operation. The lower energy consumption, short tap-to-tap time, and consistent furnace operation bring increased productivity and safety.

Aug 16, 2017

By B Robertson

Over the 40 years that the author has been engaged in the Australian underground coal mining industry, there has been a continuous improvement in safety performance as the sector has grown in size and productivity. The underground environment hosts many hazards with significant risk profiles that are kept in check by effective health and safety management systems that have evolved largely following major underground disasters. Observations are made on the changes observed for specific aspects of the underground coal sector, with particular reference to ventilation issues, and predications are made as to the needs of the future.CITATION:Robertson, B, 2013. Past achievements and future challenges in the underground coal sector, in Proceedings The Australian Mine Ventilation Conference , pp 27-32 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

By I-H. Jung, J. Kim

"Mg alloys are extensively used as light structural materials in modern industry. Mn and RE (rareearth) metals are effectively used as alloying elements to enhance the properties of Mg alloys. Therefore, the thermodynamic database of those alloys is important in the Mg alloy design and processing. Critical evaluation and optimization of all available literature data for the Mn-RE systems were conducted to obtain reliable thermodynamic functions. The Mn-RE systems shows systematic changes in the phase diagrams and thermodynamic properties with increasing atomic number in the lanthanide series. This systematic approach for all RE elements allows to resolve inconsistencies in the available experimental data. INTRODUCTIONRare Earth (RE) metals are widely used in many industrial fields including permanent magnet, electronic materials and structural materials. As a small addition of RE can enhance magnetic, electronic, optical and mechanical properties of numerous materials, the usage of the RE is still expanding regardless of the strategic control of their supply.Magnesium alloys are getting great scientific and industrial attention as the lightest structural materials. One of the drawbacks of Mg alloys is their poor formability at room temperature due to the limited slip system with hcp crystal structure. Recently, several studies (Farzadfar et al., 2011; Sandloebes et al., 2010; Stanford, 2010; Stanford et al., 2008; Yan et al., 2010) show that the additions of small amounts of RE can considerably enhance the ductility of Mg alloys. Therefore, a lot of research on Mg-RE alloys is undergoing to clarify the role of RE on the enhanced deformation mechanism and to find out the most optimum Mg alloy compositions. In order to respond to the need of Mg-RE alloy development, a large thermodynamic database for Mg alloys containing RE has been developed with critical systematic analysis and optimization of the entire RE series data. This includes the thermodynamic database of the Mg-RE (Kang et al., 2009), Mg-RE-RE (Kang et al., 2009), Mg-Al-RE (Jin et al., 2011; Jin et al., 2010), Mg-Zn-RE and Mg-Mn-RE systems."

Jan 1, 2012

By Gordon Sproule

THE papers presented to the Institute, and published in the BULLETIN, in the past three years, may be classified as follows: Geology, Mining, and Milling 89 or 58.5 per cent Smelting, Refining, and Refractories 17 " 11.2 " Mechanical and Physical Metallurgy 7 " 4.6 " General (Economics, Welfare, etc.) 39 " 25.7 " Total 152 100 These figure~ should be excuse enou.gh for. the present paper. As indicated by the title it is proposed: I.-To review briefly some of the more recent developments of Physical Metallurgy; and 11.-To show how Physical Metallurgy functions as the link between mining and production metallurgy on the one hand, and consumption engineering on the other hand. Io these days of specialization, papers of the kind being considered mostly gravitate to the American Society for Metals, the American Society for Testing Materials, the Institute of Metals, and the Iron and Steel Institute. In proof that there is a place for the newest and most specialized of these societies, the American Society for Metals, it may be said that in the Montreal Chapter there are 200 active members, and in the Ontario Chapter more than 200. Yet the overshadowing glamour of the mining industry proper, and the publicity it receives, result in an almost continuous dearth of students in metallurgical engineering at our universities. There are more jobs than graduates.

Jan 1, 1936

By W. A. SLOAN, G. L. Oldright, J. D. Sullivan, E. K. PRYOR, A. F. HALLET, R. S. Dean, S. L. BROWN, F. S. Wartman, A. J. Thompson

Lack of sufficient publication funds has resulted in the accumulation of considerable unpublished experimental work on copper metallurgy by the Bureau staff . The present report gives extended abstracts of this work , as well as a discussion of the best direction for future efforts . The experimental work reported in this series of papers was done in cooperation with the University of Arizona , Tucson , Ariz . The investigations covered in the third , fifth , and seventh papers were done under the direction of G. L. Oldright and the remainder under the direction of V. H. Gottschalk .

May 1, 1934

By Robert Horwood, Richard Harvey

The copper stave was a development of the Blast Furnace cooling system intended to utilise the high heat transfer properties of copper within a fully covered shell cooling solution. They were originally conceived as being able to provide a permanent cooling lining for use primarily in the higher heat zones of the Blast Furnace. Despite a large number of campaign successes around the world the everlasting concept has not proven universal, with some plants having suffered issues in two particular areas: stave bending (leading to water leaks at back of the stave) and stave wear (erosion on the hot face). Primetals Technologies have in the past been approached to provide assistance to a number of Blast Furnace operators who were experiencing operational issues with the copper stave furnace cooling systems of others. Through knowledge gained resolving these issues, and with the positive experiences of their own copper stave designs, Primetals Technologies have worked towards developing a new concept in copper stave design capable of providing a more robust solution to cope with the greater productivities of modern ironmaking. This paper will provide an outline to the concepts that have driven the design of this new technology.

Oct 1, 2019

By Andrea Codutti, Gianni Tiussi, Andrea Tonnicchi, Morris Codarin

Essar Algoma Steel, Canada, awarded Danieli Transimissions a strategic order for the upgrade of the main drive spindles belonging to the most loaded stands of the Hot Strip Mill, F1-F2, F5 and F6. Featuring special heavy duty design and advanced torque monitoring system, these spindles replace existing competitors’ grease lubricated design with the efficient continuous oil lubricated solution to withstand the tough working conditions, increase life expectations and provide room for a product mix extension. The first couple of spindles have been installed in September 2017 by the expert Service team and are showing already good and reliable performance. Progressively all the others are being installed.

Oct 1, 2019

By B. S. Ignasiak, Dennis Carson

"Laboratory study of the behaviour• of binary coal blends shows that coke strength is more closely dependent on the distribution of ""reactive"" oxygen in the parent coals than on their proximate, elemental or petrographic compositions, and it also appears possible to qualitatively predict coke strength from information about reactive oxygen. Proceeding from this recognition, experiments were carried out to test the possibility of preparing metallurgical cokes from binary blends in which non-caking hvb coal was substantially freed of reactive oxygen by prior heat t1•eatment under controlled conditions. The results indicate that such blends can yield surprisingly strong cokes and that coke strength may be amenable to further improvements by modifying the size distribution of the pre-heated component and the rate at which it is charred."

Jan 1, 1976