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By R. P. Smith, L. S. Darken

FOR a high-purity iron-carbon alloy, the phases existing at equilibrium at temperatures slightly above the temperature of the metastable eutectoid are austenite and cementite (hyper-eutectoid) or austenite and ferrite (hypo-eutectoid) and those below the eutectoid temperature (carbdn content > 0.02 pct) are ferrite and cementite. Such an alloy, held in a carefully controlled and measured temperature gradient (about 1 cm per deg) which includes the eutectoid temperature, then quenched and examined metallographicall.y, provides a precise measure of the eutectoid temperature. The samples were hollow cylinders approximately 1.3 cm OD, 0.63 cm ID, and 2.5 cm long, which had been carburized to the desired carbon content at 1000°C with an appropriate hydrogen-methane mixture. In order to cool the samples to room temperature with a minimum change of carbon content and absence of cracks they were quenched in a Cerro Bend bath at 480°C, followed by a water quench to room temperature. Three cylinders were suspended in the furnace1 in a purified helium atmosphere, by a closed end, thin wall, silica tube which also served as a thermocouple well. The top and bottom cylinders served only as a means of making the temperature gradient along the center cylinder more uniform. The temperature was determined with a platinum-platinrhodium thermel calibrated by comparison with a thermel certified (* 0.5OC) by the National Bureau of Standards. After holding in the temperature gradient for 24 to 72 hr the samples were quenched in Cerro Bend at 480°C, followed by

Jan 1, 1960

By Charles Hart

A STUDY of the various ores that have been discussed impresses one with the need of beneficiation, in many cases. This applies to the ores that have lain dormant, due to necessity for further preparation, or to ores that now find a market due to a changed condition. Processes of beneficiation will come into their own as our richer ores become exhausted. Many efforts at improvement have been commercial failures, due to prematurity. Thomas A. Edison, with characteristic foresight, attempted concentration of the low- grade New Jersey magnetites some thirty years ago. Due to high costs and the discovery of the Mesabi range, his efforts were futile. However, a successful crusher, designed by Mr. Edison, resulted from this attempt. Agglomeration of concentrates had not, at that time, been brought to its present efficiency, when sinters and briquettes of excellent physical condition are obtainable. Recent efforts in the beneficiation of the lean magnetites of the East Mesabi resulted in an excellent sinter, but that operation is also ahead of its time.

Jan 1, 1929

By W. A. Lang

RESEARCH has been defined as the link between the present and the future. Science, wonderful though its achievements may be, has but scratched the surface of the unknown. Research is directing its attention to winning new facts in order that their application to the processes of today may open up new sources of wealth for the common benefit. Two classes of research investigations are often recognized-fundamental and applied, but these classes merge into each other and it is often hard to distinguish one from the other. Fundamental research is carried out primarily to develop basic facts, but frequently these are found to have immediate economic value, while applied research, specifically aimed at economic values, often necessitates a preliminary fundamental investigation. Both are essential and both should proceed by scientific method. It is obvious in fuel technology that a knowledge of the physical and chemical constitution of the various coals is fundamental to their industrial utilization, and further, a knowledge of the way these coals react under different conditions of temperature, atmosphere, etc., is necessary in solving such problems as storage, combustion, carbonization, gasification, or con-version to liquid fuels. The wide range of coals, the complexity, of their constitution, and the many uses for coal, makes fuel research no simple subject but one with unending possibilities. The Research Council of Alberta, formerly known as the Scientific and Industrial Research Council of Alberta, was established in 1919, to promote the development and conservation of the natural resources of the Province. The work of the Council was arranged in six major divisions: Fuels; Geology; Road Materials; Soils; Natural Gas; and Forest Products. The office and laboratories are located in the University of Alberta. The Council was financed until the depression of 1933 by a separate vote of the Legislature, but since then has been continued, though on a much smaller scale, as one of the activities of the University. It might, however, be noted that although the Council is now in abeyance, a skeleton organization has been maintained so that it can be brought back to active service as soon as conditions warrant. Annual reports are still submitted to the Legislature. Funds have not been made available, however, for the publication of the last five reports.

Jan 1, 1942

By A. B. Hooker, L. C. IlsLey

Several ignitions or mine pa, which might have led to explosions, and at least ona mine fire attributed to heated leg wires of electric detonators, have occm.rred. at rn1::.es in which outside shot firing is practiced. Photographs taken at one mine ind.la.ted. that the wires became red hot during firing. These results having been --i·-led. to the .Lttention of the electrical section of the Bureau of the Mines, ignitions the tests and to reportd aid in herein preventing were made future to trouble determine of if this possible kind, the cause of The investigation, which 1• considered preliminary, included tests to determine the conditions tha.t cause gas ignitions from heated. leg wires of electric and. of detonators, copper leg possible wires, remedies The tor samples such of heating, wire used. and in the the relative test were behavior the of reg\llar ironDa. Pont iron and copper leg wires (No, 22 A,W,G.) C\1t from Du. Pont electric detonators.

Aug 1, 1922

By R. R. Bassermann

THE property of Howey Gold Mines, Limited is situated at Red Lake, Ontario, one hundred and seventy-five miles east of Winnipeg and eighty miles north of the Canadian National Railway line. The mine has been a continuous producer since April, 1930, and at present is hoisting 1,350 tons of ore per day. The shaft consists of three compartments (see Figure 1, sketch B). Hoisting is done by two skips in balance, one of which is interchangeable with a cage. Sinking had been carried out at three different periods. From the surface to the 550-foot level, the sets had been spaced at seven-foot intervals, from the 550-to the 1,060-foot level at six feet, and from the 1,060-to the 1,500-foot level at five feet. During the five years of operation, the shaft had become so badly worn, due to spill from the tipples and, to a certain extent, from the loading pockets, that re-timbering was considered necessary. It should be explained that no crushing is done underground because of the ad verse effect this would have on the efficiency of the sorting. The grizzly rail clearance above the ore pockets is fourteen inches and consequently the ore hoisted is extremely coarse. More than average spill from the loading pockets and tipples under such conditions is inevitable, and it is debatable whether underground crushing with consequent increased sorting costs would not be justified. The cost of complete re-timbering according to standard practice would have been prohibitive both directly and indirectly: A lengthy shut-down of the shaft, with the consequent disorganization of the staff and workmen, could not be considered. Accordingly, it became necessary to devise some method of repair that could be carried to completion in a very limited period of time. The shaft timber for the first 250 feet was not in need of repair. From the 250-foot to the 1,060-foot level the wall plates, posts, and blocking were in good condition. These had been protected by a one-inch plank lining put in at various periods during the past three years without interfering with hoisting operations. The end plates and dividers, however, could not be protected in this manner because of the lack of skip clearance. It was decided that, if the dividers in this section could be replaced, the shaft would be as satisfactory as if completely re-timbered. Several factors had to be taken into consideration in deciding on a suit-able method of repair. In the first place, the tipple plates had to be re-designed. To complete the job in a reasonable time, not only had work to be done on the tipple, but simultaneously from several points in the shaft itself. Since all power cables, pipe lines, etc., were in the manway compartment of the shaft, this compartment had to be left undisturbed.

Jan 1, 1935

By R. K. Carnochan

MANY improvements have been made in recent years in the milling of industrial minerals and it is the purpose of this paper to review some of the more important innovations that are now being used in the preparation of these products. Some of the observations which will be made have been prompted by what was seen on a recent trip to industrial mineral milling plants in the north and central sections of the eastern United States. The flotation plants visited were those of the Valley Forge Cement Company at West Conshohocken, Pa., the International Agricultural Corporation at Mount Pleasant, Tenn., and the Aluminum Ore Company at Rosiclare, Ill. Besides these, sand plants in Pennsylvania, West Virginia, and Ohio, coal-cleaning plants in Pennsylvania, pyrophyllite, mica, feldspar, clay, and kyanite plants in North Carolina, and a zinc mill and the Tennessee Valley Authority ceramic laboratory in Tennessee were visited. The milling of industrial minerals can be considered under three broad headings, namely, crushing, grinding, and purification. Usually there is both a separation and grinding problem in treating an industrial mineral, but the problems are distinct, although sometimes a separation is made while grinding, as in the case of a Raymond throw-out mill, which grinds and at the same time throws out most of any hard material present in its feed.

Jan 1, 1939

By Zhijing Zhang, Ramana G. Reddy

"The viscosity of molten oxides is one of the important physical properties since viscosity has a decisive influence on fluid flow. The knowledge of the viscosity of molten oxides is essential for modeling and controlling of metallurgical process. In the present study, viscosities of high basic Na2O-B2O3 and Na2O-SiO2 binary melts and viscosities of Na2O-SiO2-B2O3 ternary melts were measured as a function of temperature and composition. Experiments were carried out using rotary viscometer and graphite components. Our experimental results were compared with those in literature. Based on the current experimental data, the previously developed viscosity model was modified. The characteristic features of viscosities of these melts have been discussed. The predicted viscosity results are in excellent agreement with the present experimental data in the temperature range with molten state samples. IntroductionThe viscosity of molten oxides is one of the important physical properties since this property has a decisive influence on fluid flow, and is one of key factors to be taken into consideration in process modeling. The manufacturing operations require the viscosity of molten oxides to be within certain ranges. Although, some viscosity measurements on borosilicate systems have been carried out [1-4], the viscosity data in literature are available only for a few temperatures and cover small composition ranges. The agreement between the results of these works is not satisfactory [I-4]. Even the viscosities of binary systems Na2O-B2O 3 and Na2O-SiO2 generally are well studied, the available viscosity data in literature are only found in the composition range of O to 0.333 mole fraction ofNa2O. The aim of the present study is to provide a base with accurate experimental data for reliable model extrapolation."

Jan 1, 1999

By Peter J. Clarke

Afghanistan's mineral industry continued to be dominated by the production and export of natural gas, although several mining and related industrial projects, all under the supervision of Soviet technicians, were in the planning stage in 1982. Afghanistan produced minor quantities of barite, cement, coal, fertilizer materials, iron, and lapis lazuli, all for domestic consumption.2 Large-scale projects being investigated were a copper mine and concentrating plant at Ainak, extensive mining of the Hajigak iron ore deposit near Kabul, construction of an oil refinery at Angot, increasing production and processing of natural gas, and implementing an intensive geologic prospecting and exploration program for areas of mineral potential. Afghanistan's gross domestic product (GDP) was estimated at $2.76 billion3 and has remained stagnant for the past several years. Total exports in 1982 were estimated at $700 million, only a marginal increase from the 1981 figure of $694 million. Exports of natural gas to the U.S.S.R. earned $385 million in 1982, representing just over one-half of Afghanistan's total exports. Natural gas revenues were down approximately 11% from the 1981 level, owing primarily to increased antigovernment activity in the northern part of the country.4 About 90% of the country's natural gas production was exported to the U.S.S.R.5 About 38% of Afghanistan's development budget had been earmarked for mining and industrial projects in 1982.6

Jan 1, 1984

By P. W. J. Delport, E. Du Toit

Investing in a mining venture can be risky and stakeholders need transparent, unbiased reports to understand the Mineral Resources and Mineral Reserves a mining company holds. Readability and textual choice can be used consciously to manipulate perceptions, or it can be done unconsciously. This exploratory study investigates the readability and textual choice of supplementary Mineral Resources and Mineral Reserves Reports of companies listed on the Johannesburg Stock Exchange. The results indicate that narrative manipulation occurs in these reports through word choices that make the reports difficult to read, as well as specific narrative selections. This reduces the informational value of the reports. The results of the study will be useful to various stakeholders, such as mining company management, investors, investment specialists, financial analysts, and even employees and the general community, who all use these reports to make important decisions. It is also useful for the preparers of the Mineral Resources and Mineral Reserves Reports, Competent Persons, and other technical specialists to be aware of readability and that certain textual choices can affect the interpretation of these reports. It is recommended that bodies such as the JSE and the SAMREC and SAMVAL Code committees consider adding a plain language requirement to regulations, guidelines, and codes to ensure transparent, unbiased, and objective reports.

Mar 1, 2021

By Yutaro Fukase

Various types of service robots have recently been developed for guarding facilities, caring for the elderly, carrying objects, and cleaning buildings. As barrier-free facilities improve and their use expands, these robots have more space within which to move inside buildings. Yet robots that move autonomously rely on position-detection systems. Though improving rapidly, these systems are far from perfect in determining positions in certain situations, especially when robots navigate large areas or cross various locations. Our group is working to solve this problem by developing a position-detection system using random-dot patterns on a floor. First, we construct a floor with a random-dot pattern and register the positions of all of the dots into a database. As the robot moves across the floor, a camera on the robot captures an image of the floor beneath it and crops the dot pattern in the image. The cropped dot pattern is matched to the dot patterns in the database to determine the position of the robot and the direction in which the robot is facing or moving. In this paper we propose a self-localization system and matching algorithms derived from a space technology and present the results of several experiments.

Aug 1, 2013

By G. Howell, J. Wates, A. Coetzee, C. J. MacRobert

The Global Industry Standard on Tailings Management (GISTM) requires mining companies to make four key appointments as part of their tailings management structure. These four positions are an Accountable Executive with policymaking responsibilities, a Responsible Tailings Facility Engineer with operational responsibility, an Engineer of Record to ensure facilities are designed, operated, and closed safely, and an Independent Tailings Review Board to assess safety drivers regularly. Little guidance on the traits of these individuals is available in a South African context. Consequently, the tailings community of practice was surveyed to develop a table of ideal competencies and establish the flexibility in meeting these traits.

Jun 2, 2022

By Hans E. Madeisky, Bruce W. Downing

Abstract-The acid rock drainage (ARD) buffering capacity of mine waste is governed by its bulk chemical composition and its mineral assemblage. Conventional acid base accounting (ABA) tests can be used to predict short-term buffering, but should be used with caution to model or predict the long-term ARD buffering capacity of mine waste. ABA data for mine waste samples from four different deposit types: anorthosite-hosted magmatic sulfide nickel, dunite-hosted magmatic sulfide nickel, porphyry copper-gold, and volcanic-hosted high sulfidation epithermal silver, were compared with whole-rock geochemical and petrographic data obtained from the same samples. Our objective was to devise and test a method of predicting ARD buffering capacity based on bulk chemistry and modal mineralogy. In other words, we developed a quantitative theoretical method for calculating neutralizing potential, relying on easily obtainable and relatively inexpensive whole-rock and sulfur XRF analyses, which could substitute for conventional ABA procedures in situations where these procedures are either too costly or too time consuming. For each deposit type, models were devised that reasonably approximate the net neutralization potential estimated by the ABA data obtained from laboratory tests. Once an appropriate model has been developed and tested, portable X-ray fluorescence equipment, already used for grade control at many mine sites, could provide the wholerock and sulfur analyses required to estimate the ARD potential of the waste material. Although this approach is not intended as a substitute for the legally mandated ABA test procedure, it could facilitate the timely and cost-effective management and mitigation of ARD at a mine site.

Jan 1, 1997

By D. S. Salonine

Aluminum alloys are widely used in modern industry. Tubes and hollow shapes give great opportunities for structural purposes as well as fluid transport due to their stiffness and lightness, Extrusions on a mandrel or through a bridge die, that requires splitting of the billet with re-welding, produce hollow shapes with varied contours, fins and multiple cavities. Moving and stationary mandrels, mandrel lubrication, tooling for ribbed-tube heat exchangers, and for drilling pipes are considered. Bridge dies can be classified by the bridge position relative to the die face, by mandrel support structure, and by assembly type, The main parameters influencing the quality of the die-welded seams are considered, The difficulties of extruding various alloys through bridge dies are discussed in terms of metallurgical factors, Some approaches to the calculation of the stresses in a bridge are presented.

Jan 1, 2005

By Hans E. Madeisky, Bruce W. Downing

The acid rock drainage (ARD) buffering capacity of mine waste is governed by its bulk chemical composition and its mineral assemblage. Conventional acid base accounting (ABA) tests can be used to predict short-term buffering, but should be used with caution to model or predict the long-term ARD buffering capacity of mine waste. ABA data for mine waste samples from four different deposit types: an orthosite-hosted magmatic sul?de nickel, dunite-hosted magmatic sul?denickel, porphyry copper-gold, and volcanic-hosted high sul?dation epithermal silver, were compared with whole-rock geochemical and petrographic data obtained from the same samples. Our objective was to devise and test a method of predicting ARD buffering capacity based on bulk chemistry and modal mineralogy. In other words, we developed a quantitative theoretical method for calculating neutralizing potential, relying on easily obtainable and relatively inexpensive whole-rock and sulfur XRF analyses, which could substitute for conventional ABA procedures in situations where these procedures are either too costly or too time consuming. For each deposit type, models were devised that reasonably approximate the net neutralization potential estimated by the ABA data obtained from laboratory tests. Once an appropriate model has been developed and tested, portable X-ray ?uorescence equipment, already used for grade control at many mine sites, could provide the whole-rock and sulfur analyses required to estimate the ARD potential of the waste material. Although this approach is not intended as a substitute for the legally mandated ABA test procedure, it could facilitate the timely and cost-effective management and mitigation of ARD at a mine site.

Jan 1, 1997

By D J. Brake

The risk from fire remains one of the most serious of underground mine disaster scenarios. The impacts of mine fires on the underground ventilation system and the production of toxic gases have been difficult to model and therefore assessments have relied largely on empirical data, historical precedent and subjective opinions. Underground fire modelling software has had limited availability and been technically challenging and time consuming to use especially for routine mine investigations. There has also been no well-accepted set of assumptions for fire modelling in mines, which has resulted in a lack of confidence in adopting its use more widely. This paper describes modelling of three critical fire scenarios in underground hard rock mines: a fire (LHD) in an underground diesel refuelling facility, a fire in an underground explosives magazine and a fire on an underground ore transport conveyor. Modelling was undertaken using VentsimÆs VentFIREÖ fire simulation module. It describes the basis of design, the key assumptions, the methodology used and provides examples of the outputs, conclusions and recommendations. It reviews the impacts of these fires on egress and entrapment strategies in the mine. Some general principles regarding improvements to ventilation circuit design based on this analysis are also recommended. Whilst the fire scenarios were based on actual case studies, they have been disguised for this paper.CITATION:Brake, D J, 2013. Fire modelling in underground mines using Ventsim Visual VentFIRE software, in Proceedings The Australian Mine Ventilation Conference , pp 265-276 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

By C. E. Jordan

Abstract. The U.S. Department of the Interior, Bureau of Mines, as part of its effort to maintain an adequate supply of minerals and metals to meet national economic and strategic needs, is conducting research on the pneumatic recovery of coarse mica. A system of crushers, screens, and zigzag air classifiers is used to concentrate coarse liberated mica particles from mica ore and from the waste tailings of abandoned mica operations. The plus 0.21-millimeter-size mica is effectively recovered by this method. The mica concentrates produced contain over 90 percent mica. The method recovered up to 78 percent of the mica in the samples. As a dry concentration method, the pneumatic-beneficiation technique may be advantageous in areas of limited water resource.

Jan 1, 1980

By W. H. Strickland

The research reported here characterizes ultrasonic ranging sensors for autonomous navigation on underground mine mobile equipment. Because ultrasonic rangers are inexpensive, have no moving parts, have no lenses to clean, are small and unobtrusive, and can measure distances in dusty environments, they are especially sui ted to underground mi ne environments. The investigation began with laboratory tests of field of view, angle of incidence, intersensor variation, and ranging accuracy of individual rangers and a ring array of 24 sensors. The results showed the sensors have good accuracy and low variability. Additional experiments at AHAX' s Henderson mine Showed the sensors could accurately and reliably measure rib features, convex and concave corners, and drift intersections. The results showed that when used and analyzed properly, the sensor data may be used reliably for underground mobile equipment navigation.

Jan 1, 1990

By A. Chamanara

The gross vehicle weight (GVW) of an ultra-class mining truck comprises the unsuspended weight below the struts plus the suspended empty vehicle weight, plus the payload. Theoretically, one third of the suspended total weight is supported by two front struts and two thirds by two rear struts. However, since the payload position is not fixed when placed in the truck body and varies from load to load, compounded by uneven haul road profiles, the truck structure experiences higher than normal stresses, which manifest in the reduction of the life of the truck via structural fatigue. The downstream effects are a decrease in production and increase in operational and maintenance costs. In order to control the dynamic forces causing the high stresses on the truck structure, both the haul road conditions and the load distribution in the truck body need to be investigated. The latter aspect is the prime focus of this paper. A field test has been conducted in an oil sands mine where the Caterpillar 797B trucks are loaded by a Bucyrus 495 shovel. The strut pressure readings are collected using the data-loggers on the trucks as well as the truck velocity associated with each reading. Rack, roll and pitch are the main key performance indicators (KPIs) that are calculated to study the adverse effect of an unbalanced payload and consequently the truck structure. Finally, the shovel bucket load passes within the truck body are simulated and a new method is suggested to improve the truck payload balance.

Aug 1, 2013

By Long Fan, Shimin Liu, Guijie Sang

"Weak shale roof falls have long been the main cause for fatalities in underground coal mines. Moisture-induced swelling is one of the root causes for the degradation of roof shales. In this study, slake durability tests are conducted on shale samples collected from Illinois basin coal mines, and different levels of durability are analyzed according to Gamble slake durability classification. There are two main mechanisms influencing the shape of retained fragments after two cycles of wetting and drying: mechanical abrasion and swelling pressure. A prototype optically based shale swelling apparatus is designed and manufactured for the shale free-swelling measurement. The experimental results suggest that swelling pressure tends to deteriorate shale laminations. Moisture-induced swelling of the No. 6 roof shale from Bear Run Mine was measured under 100% relative humidity condition. The measured swelling strain normal to beddings is ~5 to 7 times greater than the swelling strain parallel to beddings. This suggests that interlayer expansion plays a key role in moisture-induced swelling. Cracks induced by swelling pressure tend to occur along the bedding plane and lead to shale deterioration. INTRODUCTION Background Ground falls have long been the cause for nearly 50% of all fatalities in underground coal mines and continue to be one of the greatest safety hazards in underground spaces. Among the various ground fall hazards, roof failure takes up 23% of total fatalities in underground coal mines, of which 13% are due to skin failure and 10% are due to massive roof falls (Mark, Pappas, and Barczak, 2011). Roof failures associated with weak shales are summarized in previous studies (Molinda and Mark, 2010; Aughenbaugh and Bruzewski, 1973; Bajpayee, Pappas, and Ellenberger, 2014; Murphy, 2016). For mine roof instability and failure, two aspects can explain the failure mechanism of weak roofs. One is the elevated stress concentration in lateral direction due to the mining-induced excavation and its stress redistribution around the mine opening (Song and Stankus, 1997; Fan and Liu, 2017; Hill, 1986). The other mechanism is the passive stress-relief due to the strength weakening induced by the ambient moisture and temperature fluctuations during a period of time. Shale is moisture sensitive and presents a lower durability if it is exposed to a highly humid environment for a long time, thus leading to roof deterioration and instability in underground coal mines (Aughenbaugh and Bruzewski, 1976; Stateham and Radcliffe, 1978; Chugh and Missavage, 1981; Klemetti, Oyler, and Molinda, 2009). It is well known that shale is a clay-bearing sedimentary rock and that clay minerals are water sensitive. The moisture uptake for shale will induce the micro-deformation of a shale matrix, thus the structure and strength of shale is a function of time and intensity of moisture exposure. All mine engineers notice moisture-induced shale deterioration; however, the underlying mechanism(s) are still not fully understood due to the complexity of geophysical-chemical water-shale interactions (Huang, Aughenbaugh, and Rockaway, 1986; Hensen and Smit, 2002; Diaz-Perez, Cortés-Monroy, and Roegiers, 2007). The coal mining industry is still in the process of finding a technically sound, cost-effective technology to prevent this unexpected and unpredictable shale roof failure. Therefore, understanding how the moisture-sensitive shale responses to various ambient moisture and what role exposure duration plays in shale roof failure is key to prevent unexpected roof incidents, which will lay the foundation for the long-term roof support design and ground control management."

Jan 1, 2017

By Laureano Rodríguez, Francisco Cuellar

El empleo de chimeneas de ventilación es un método ampliamente usado para aumentar y controlar el flujo de aire en las áreas de trabajo subterráneo. Sin embargo la eficiencia y seguridad asociadas a este método de ventilación dependen en gran medida del esmero que se tuvo durante la perforación y construcción de las mismas así como la forma interna y estado que tienen actualmente. Dados los requisitos actuales de aumento en la productividad y seguridad en las operaciones mineras del país, la empresa Tumi Robotics inició un proyecto de investigación y desarrollo de un sensor móvil que permita visualizar, diagnosticar y digitalizar el interior de chimeneas verticales de ventilación para minería subterránea.

Sep 29, 2023