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By N. Mashaba, D. Botha

The aims of this study were to investigate the factors that influence women’s engagement in technical positions in the South African mining sector and to determine what could be done to promote their successful participation. A convergent parallel mixed-methods research design was used to ascertain the factors that facilitate, inhibit, and influence engagement. In the quantitative phase of the study, questionnaires were circulated to women employeees; and in the qualitative phase, semistructured interviews were conducted with employer representatives, most of whom were human resource personnel. Confirmatory factor analysis showed that the three-factor structure (vigour, dedication, and absorption) of the Utrecht Work Engagement Scale fit the sample data reasonably well. Although there is room for improvement, respondents demonstrated acceptable levels of engagement in their work. On the other hand, the qualitative findings showed that employee engagement is impacted by unfavourable working conditions, work–life balance, and the mining industry’s male-dominated work culture. The findings showed that employee engagement should be elevated to a core human resource function. To increase the participation of women in mining, human resource professionals are encouraged to collaborate with mine supervisors, managers, and employees to develop programmes that promote employees’ absorption in and dedication to their work.

Nov 6, 2023

By C. J. Pretorius

More than 30 percent of the global demand for zircon (ZrSi04) is supplied by South Africa. A significant amount of the zircon is exported, and beneficiated products are then imported for industrial applications locally. Beneficiating the zircon locally could have a positive impact on the local market, since zircon is only one of many such cases. Ammonium acid fluoride serves as an alternative anhydrous fluorinating agent for zircon in the synthesis of several metal fluorides1,2. It provides an effective dry fluorinating method and is easier to handle than hydrogen fluoride or fluorine gas. Zircon exposed to extreme plasma temperatures dissociates and becomes more reactive. The reaction of the plasma-dissociated zircon (Zr02.SiO2) with the ammonium acid fluoride (NH4F.XHF, where x= 1 to 5) forms two main intermediate compounds (NH4)3ZrFr(s) and (NH4) 2SiF6(s), the latter decomposing to form volatile products at relatively low temperatures, providing easy separation of the silicon and zirconium compounds. The ammonium zirconate compound decomposes to form zirconium tetrafluoride (ZrF4), which can be further manufactured into zirconium metal, to name but one product. Data on the kinetics of the reaction of ammonium acid fluoride with zircon and plasma-dissociated zircon, combined with the thermo¬dynamic parameters of the reaction, is essential for the development of an industrial process for the production of a precursor for the manufacturing of zirconium metal, namely anhydrous ZrF4. Both the reaction kinetics and reaction parameters will be included in this study, as well as some proof that the reaction proceeds to ZrF4 on a small batch scale. If the exact reaction parameters can be pinned down, a wide spectrum of anhydrous metal fluorides can be synthesized through this fluorination route.

Jan 1, 2012

By Jilai Xue

Fe-Ni alloys can be used as raw material in making stainless steel. Laterite nickel ore is one of mineral resources for producing nickel alloys. In this work, the laterite ore after dehydration at 800 °C and the anthracite as reducing agent were mixed for pre-reduction at 900 °C, and then reduced to form Fe-Ni alloys at 1550-1620 °C through carbon-thermal reduction process. A high Ni-content alloy component in the metallurgical mixture can be formed through pre-reduction. Better separation of the resulting metals from the slag is found with lower Ni-content alloys produced or higher temperatures during reduction. An effective processing of Fe-Ni alloys needs further understanding of the process fundamentals and optimizing of the process parameters.

Jan 1, 2010

By L. Boyd, A. Charland, G. Potts, D. Fragomeni, N. O. Lotter

"The Raglan orebody and concentrator has been the subject of study in Process Mineralogy at Falconbridge since 1998. (Lotter and Tuzun, 1998) The orebody is classified into three distinct textural groups, or end members. These are referred to as disseminated, net-textured, and Massive Sulphides, and differ in terms of mineral grain size, nickel grade, hardness, and mineral association. In this paper, it will be shown that the sampling and characterisation of each end member on an individual basis develops a higher-level understanding of the processing requirements and behaviour of the mixture of ore as presented to the mill.The end members have been used in robust prediction of recovery at various grind size p80 from laboratory scale High Confidence Flotation Tests. Weighted mean mixtures of the end members have been mathematically combined to determine impact of textural distribution on metallurgical performance as a function of grind size.The ore end members also vary in hardness and breakage mechanism and have been used to model throughput capability for existing, optimized and retrofit grinding circuits. This modeling has provided a range of expected throughputs as the relative proportions of each end member varies.Finally, the differing grinding requirement per end member has led to the development of grinding and flotation strategy that increases rougher flotation recovery and provides flowsheet options for a concentrator expansion. This leads to further understanding of the plant performance as a function of ore mixture."

Jan 1, 2005

By P. D. Kondos, J. R. Goode

Given the global inventory of low grade and refractory gold deposits, processes that could turn these challenged deposits into mines are of considerable interest. Such gold deposits have low value and potentially high operating costs and so they pose special challenges for the mining engineer and metallurgist. Conventionally, refractory gold ores have been processed by whole ore pressure oxidation and roasting, or flotation followed by roasting, pressure oxidation or bio-oxidation of the concentrate. Halide-based processes have recently been developed that might be applied to concentrates. Low grade refractory gold ores have been processed using heap bio-oxidation followed by cyanide heap leaching or milling. Other processes are emerging. Barrick has completed an inventory of emerging technologies (1). A summary of the current status of these developments will be presented with the view that, with additional development, some of these technologies or a combination thereof may unlock the value of these deposits.

Jan 1, 2005

By D. F. Hewett

CONTENTS PAGE Introduction 1 Geologic features of eastern Oregon 2 Geology of the Sumpter quadrangle 2 Rocks older than the ore deposits 3 Rocks younger than the ore deposits 8 Lodes of the Sumpter quadrangle 8 Areal distribution 8 Geologic distribution 9 Major features of the veins 9 Mineralogy and texture of the veins 13 Ore deposits zonally disposed around the Bald Mountain batholith . . . . 13 Summary of mineralogy and texture 32 Zonal relations 33 Ore deposits zonally disposed around Greenhorn Mountain batholith . . . 36 Zonal relations 37 Relation of textural features to zonal arrangement of veins 37 Summary of zonal relations 38 Comparison with similar districts 39 Outlook for the district 40 INTRODUCTION IN an earlier report on the Sumpter quadrangle1 it was briefly stated that the quartz lodes of that region might be separated into several groups or belts on the basis of the kind and abundance of the minerals of which they are composed, and that these belts were disposed as areal zones around the principal intrusive mass of the region. When the opportunity to revisit the region was offered in 1929, as a result of a cooperative agreement between the State Mining Board of Oregon and the United States Geological Survey, it seemed advisable to pay particular attention to this feature of the lodes, in the hope that if the idea of zonal relations was confirmed it might serve as a guide in exploitation.

Jan 1, 1931

By A. J. Fejes

The purpose of this Bureau of Mines report is to provide mining industry personnel and regulatory authorities with a subsidence-reference list and annotated bibliography that will aid them in locating subsidence information and in developing their own subsidence information sources. Over 700 references are listed in the Bureau's subsidence information center bibliography; approximately 600 of these references were obtained for assessment. Of these 600 references, 167 were selected to be rated, categorized, and annotated. All literature referenced in this report was published prior to 1984. Table 1 is a cross - referenced index that classifies and rates selected references with respect to specific keywords. References are rated not on quality of content but rather on applicability to given subject areas. Appendix A is an annotated bibliography of the references listed in table 1 and provides further information of each article to aid the user in selecting articles for specific areas of subsidence technology. Appendix B is a copy of the subsidence information center bibliography.

Jan 1, 1985

By R. C. A. Thurston

INTRODUCTION THE deleterious effect of stress raisers or notches on the resistance to fatigue of machine components, and other parts subjected to repeated dynamic loading, has been well known for many years. Most engineers in the mechanical field have, at one time or another, encountered a shaft which fractured due to a poor transition fillet, a holding-down bolt which failed due to insufficient tightening or inferior thread form, or a fitted member which broke through a combination of fretting corrosion and clamping stresses. All of these are examples of the damaging influence exerted by stress raisers in fatigue. Other common forms of stress raiser which have taken their toll of dynamic components are: keyways, oil holes, splines, quenching oil grinding cracks, tool marks, and sharp changes in section; some are the result of the design, others of poor execution of the design. It is our experience in the Mines Branch1 and I feel sure this will be corroborated by other fatigue investigators, that the majority of failures are due to incorrect design or faulty preparation of the part concerned, rather than to the use of inferior material. Quite frequently, it is true that the operating conditions necessitate the presence of a 'notch', but even in such cases methods are generally available by which its adverse effect on the life of the component can be reduced or annulled. The purpose of this paper is to discuss a few typical stress raisers, and to provide information on various processes for mitigating their effects in fatigue.

Jan 1, 1951

By J. F. Lupo

Heap and valley leach operations rely on solution collection piping placed within the heap to enhance both solution recovery and to assist overall solution management. The most common piping used in leaching operations is solid or perforated High Density Polyethylene (HDPE) pipe and Corrugated Polyethylene pipe (CPE). These pipes are widely used because of their low cost, ease of installation, durability, and flexibility. The typical recommended maximum design depth of burial for HDPE and CPE pipes is on the order of 30 meters (100 feet). However, ore heap heights at many facilities exceed 30 meters and some are now approaching 180 meters (600 feet) in height. At very high ore heap heights, the stability and performance of HDPE and CPE pipes becomes a critical issue for leaching facility design and operation. Failure of solution collection piping can lead to poor solution recovery, high hydraulic heads on the liner system, and in some cases, unstable ore slopes due to high solution pressures near slopes. This paper presents a review of methods that have traditionally been used to evaluate pipe stability under high normal loads. A common shortcoming of these methods is the inability to account for beneficial effects of ore arching around pipes and the time-dependent creep (stress relief) behavior of polyethylene (PE) materials. A new analytical approach is developed and presented which includes the effects of ore arching around pipes and creep of PE materials. The results of the new approach show that PE pipes will deform under high heap loads, but can remain stable and functional. Pipe stability is shown to be dependent on the type of pipe backfill and initial backfill compaction. The new approach represents a useful tool for designing applications for PE pipe under high normal loads.

Jan 1, 2001

By A B. Christie

Space-based synthetic aperture radar (SAR) data is becoming available over much of the world, includingNew Zealand. Radar imagery has a number of very advantageous features, including all-weather capability; it also has artifacts, such as layover, which require processing before these data may be used to best effect.   This paper gives an outline of SAR, details the image processing required, and discusses the use of the first New Zealand Japan Earth Resources-1 SAR data to aid geological mapping on the Coromandel Peninsula.

Jan 1, 1994

By C. E. Julihn, Lowell B. Moon

"INTRODUCTION To increase the supply of ore needed to produce steel the Bureau of Mines has explored 187 mineral deposits containing chromium, iron, manganese, cobalt, nickel, fluorspar, tungsten, vanadium, or coal during the fiscal years. 1940-44, the deposits thus explored were selected from several thousand that were first examined to appraise their possibilities. The objective of the exploration was to determine the tonnage and grade of ores upon which mining, operations might be based, and the metallurgical processing that was most suitable for their utilization.Most of these deposits were sub-marginal by pre-war standards; hence there had been no incentive for their exploration, yet many such deposits were known to exist that probably contained ore sufficient in grade and amount to be utilized as war reserves.Some of the Bureau's exploration projects have disclosed substantial or even very large amounts of ore, much of which is fairly high in grade. In a few of them bodies of high-grade ore have been found, though in others the tonnage has proved to be too small or too low-grade for utilization."

Mar 1, 1945

By C. Derek Martin

"Predicting the ground response for tunnels in weak shales remains challenging. Predicting the ground response is challenged by difficulties in characterising the material, and our ability to predict deformations that are driven by coupled hydromechanical processes, when this material yields. The techniques that are used for characterizing weak shales are reviewed, and three case histories are examined that demonstrate the behaviour of these weak rocks during tunnelling. A general framework is provided for assessing the squeezing potential for weak shales.1 INTRODUCTIONGeologically, shale is an argillaceous fine-grained sedimentary rock that forms from the compaction of silt and clay-size mineral particles commonly referred to as ""mud"". Because of this grain size, the material is generically classed as Mudstone (Figure 1). Shale is distinguished from other mudstones because it is made up of many thin layers (laminated) and readily splits into thin pieces along the laminations (fissile). While the geological classification of shale appears straightforward, the classification for engineering purposes is often confusing. Underwood (l967) provided the first description of shale that made the distinction between “soil-like” compaction shales and “rock-like ""cemented"" shales. He coined the term ‘clay shale’ to capture the characteristics of hard clay yet recognizing its origin as a shale. In this paper weak shale is synonymous with clay shale and have strengths that typically range from R1 to R2 (1 to 25 MPa). Characterising these materials draws on methods from both soil and rock mechanics."

Jan 1, 2015

"THE CONCEPT of energy as a commodity, while not entirely new, is not as widespread as the importance of the idea to this modern world would lead one to expect. The growth in the supply and use of energy over the past years has been tremendous, but our very closeness and familiarity have somewhat distorted the viewpoint, particularly of the younger generation. To many of us who remember the wonderful satisfaction of our first responsibility for directing two horsepower hitched to a farm cart or hay wagon, there still arises a feeling of some awe at the casual flick of the switch with which our sons and daughters summon to their convenience the service of some one hundred or more horsepower.Energy is the vital component of our existence and, no matter what contempt our day-to-day familiarity may •breed, it is wise to .pause from time to time and consider our national energy standing. Have we still capital in the bank? Are our expenditures wisely •conceived and well directed? Is provision being made for the years •ahead for the needs of our children and our children's children?"

Jan 1, 1953

Supplement to Proceedings Number 120, December, 1940. Drawings accompanying paper by T M Carey 'The Surface Plant at the Zinc Corporation Mine, Broken Hill'

Jan 1, 1940

By Bruce Gellar

In March, the Prospectors and Developers Association of Canada (PDAC) held its annual conference in Toronto, Ontario. This is the third PDAC meeting the author has attended. The following are some impressions of the meeting. And the author looks forward to the joint meeting of the PDAC and the Canadian Institute of Mining, Metallurgy and Petroleum to be held March 5-10, 2000, entitled Mining Millennium 2000. One of the features of next year’s gathering is a proposed forum of world mining ministers, the first ever to be held anywhere.

Jan 1, 1999

By H. P. Rosenof

The G2 real-time expert system, a commercial product since 1988, is widely deployed in process, manufacturing and other industries. A number of innovative applications are installed or under development in the mining and metallurgical industries. These include: ? A chemical reagent control system for a mineral concentrator, at a mining company; ? A supervisory control system for a product dryer, at a surface coal mine ? A training system for equipment operators, at a steel mill; ? A scheduling system for furnaces at a hot rolling mill; ? A simulation system for mining operations; ? Several graduate-level research projects in materials handling at a university Realized and projected benefits will be discussed. In addition certain applications installed or under development in other industries will be proposed as applicable in mining and metallurgy. For example, applications for the management of vehicular traffic may find use in mining and shipping.

Jan 1, 1992

By L. D. Schmidt, H. G. Graham

Several processes for the production of ultra-clean coal for electrode carbon were developed in Germany prior to and during World War II . These processes have been investigated since the end of the war by the British and U. S. Government missions . As the reports of the investigations are not readily available to the public , it is the purpose of this paper to present the information which has been obtained regarding the methods by which ultraclean coal was produced . Almost all the ultra-clean coal was used in the manufacture of electrodes for the production of aluminum and magnesium . Standard raw materials for making these electrodes are pitch coke and petroleum coke , which are nearly ashless . The inclusion of ash in the electrode carbon results in lowered efficiency and impure metal from the reduction process . Petroleum coke and pitch coke were in very short supply in Germany during the war , so that it was necessary to augment the supply with carbon produced from coal . In the emergency , methods were developed to clean coal which had never before been economically feasible . However , a demand for nearly ash-free coal might develop in the United States if a shortage of petroleum coke were to occur at the same time as a strong demand for light metals . Other uses of ultraclean coal are in direct hydrogenation of coal , in production of activated carbon, and for special fuels . Specifications for electrode carbon are rather severe owing to the necessity for producing pure metal . Maximum amounts of impurities allowable in American practice are as follows : Total ash , 1.0 percent ( in finished coke , 0.7 percent ) Silica , 0.08 percent Ca or Na, or their sum , 0.12 percent Sulfur , 2.0 percent Ba , Ni , Cr , Mn , Co , and V are objectionable in very small amounts . The most important process for ultra cleaning of coal in Germany was froth flotation . Froth flotation had been used widely there to process washery -water sludges and to recover coking coal from high - ash fines . Its use was indicated , therefore , when the demand for ultra low-ash coal arose . In two plants the coal cleaned by froth flotation was treated with acid or caustic to lower further the ash content . Another process used on an industrial scale was that of dissolving the coal substance in the middle oil from direct hydrogenation of coal under controlled pressure and temperature . The resulting paste was heated, filtered , and the oil distilled off . The residue was a low-ash organic material that could be carbonized for electrode carbon or could be hydrogenated directly . Several other processes had been developed to the laboratory or pilot - plant stage but had never been used on a commercial scale . These processes included cleaning by centrifugal action , cleaning by electrostatic action , and cleaning by forming a paste with oil in water . The coal-preparation plants at the Carl Alexander mine , Augusta Viktoria mine , and Kőenigin Elisabeth mine are described in Bureau of Mines Information Circular 7389 : " Coal Preparation Practice in Western Germany" , by Thomas . Fraser and M. G. Driessen . Most of the special equipment used at these plants is described in the above publication .

Oct 1, 1948

By Bruce F. Grant

"INTRODUCTION The future of oil production in the part of the Appalachian region included in southwestern Pennsylvania; West Virginia, and southeastern Ohio is directly dependent on the maintenance of existing wells. This report presents an analytical study of the methods used in oil-well reconditioning in this area. The study is part of a research program designed to evaluate those means of stimulating oil production that can effectively and economically maintain present oil-production rates and make it possible to keep existing wells in operation. Well-reconditioning work was curtailed during the war; therefore, an abnormally large number of wells in the Appalachian Region is now in need of repair. Because the lubricant content of Appalachian crude: oils is high and the refined lubricating oils an; particularly suited to use in high speed, high-temperature engines, the demand for these crude oils during the war exceeds, the maximum rate of production obtainable under wartime operating conditions. Increases in operating, expenses, inability to meet war-time reconditioning costs, and inflexible price structures caused the abandonment of an alarming number of wells during the past 4 or 5 years.As a means of increasing regional oil-production rates, new drilling in the older fields for primary production generally is uneconomical because reservoir pressures in most of the fields have virtually been depleted and the production rates of newly drilled wells are small."

Feb 1, 1948

By E. C. Westman, W. R. Thomas, W. J. Conrad, A. J. R. Russell

"Understanding ground control problems continues to remain a focus of the mining engineering community. To aid mine operators and engineers in identifying and responding to ground control issues, the Ground Observation System (GOS) is being developed. The GOS is an integrated, web-based graphical user interface that displays ground response data collected wirelessly from an underground mine. It presents data in an intuitive manner to assist mine personnel, who are on- or off-site, in quickly identifying hazardous areas. Geotechnical instrumentation will be connected to wireless transmitters that will relay data in real-time to a surface computer that stores the information in a database. The GOS website will then display the geotechnical data in graphical and tabular forms, as well as in conditionally formatted mine maps. Data from each measurement device will be able to be viewed in its entirety or within a time interval, and can be downloaded for further analysis. The ability of the GOS to quickly interpret and communicate mine hazards to personnel of varying technical ability should prove to be a useful tool in understanding ground control and thus improving mine safety.INTRODUCTION Computer-based data information centers that convey operating parameters and conditions are prevalent in modern underground mines. Today’s systems are popular in showing ventilation controls and monitoring equipment performance (Jyothi & Meena 2013). In ground control monitoring, Conover, Ross, and Bigby, 2010 have installed a wired telltale roof monitoring system that sends roof displacement data every ten minutes to a computer on the surface. The computer receives, stores, and displays the data in real time. Data can also be viewed remotely through a password protected internet connection. Additionally, an internet connection allowed for remote updates to the system which streamlined software development and maintenance by eliminating travel (Conover et al., 2010). Currently, no such system beyond Conover et al.’s design has been accomplished. The Ground Observation System (GOS) is being developed to fill the void of real-time geotechnical monitoring in underground mines. A wide array of data will be transmitted wirelessly and broadcasted to on- and off-site mine personnel through the internet. The GOS will incorporate geotechnical data from roof deformation, borehole scratch testing, photogrammetry, and seismic monitoring into one interface, all while achieving permissibility for the use in gaseous mines. As a result, a comprehensive view of rock movement due to mining will be available. The overall purpose of the GOS is to deliver warnings; to ensure reliable data is relayed to personnel for the identification of potential ground failures, provide mine engineers information to design more stable mines, and assist with further geotechnical research."

Jan 1, 2015

By C. W. Van Law

WE have just heard a very able presentation, by Mr. J. C. Cameron, on the subject of Recent Trends in Labour Relations, as they exist today in Canada (l). With minor changes, what he said applies equally to the situation in the United States. Direct negotiation between employer and employee on a man-to-man basis, wherein good faith and mutual esteem was at least sometimes a factor, has almost entirely given way to a mass struggle in which each side is represented by highly trained specialists in a new jurisprudence, built up on vote-getting labour laws, decisions in analogous cases by Boards whose members may have had very little personal acquaintance with the specific case, etc., etc. Membership in a labour union has become almost an essential requisite to a job; once in, the individual workman loses his identity and dares not act on his own initiative or even express any idea not handed him by his Union head. An honest workman cannot turn in an honest day's work, because his Union will not allow him. Leadership in the Unions has become so powerful an instrument, both politically and monetarily, that Union policies are drafted primarily to build up that power, and may have little relation to the equities of the individual case. ?While both sides still render lip-service to the doctrine that Capital and Labour can advance best by co-operation to mutual benefit, that doctrine has in effect given way to as bitter and as legalistic a struggle as any in our civil courts. There are many reasons to believe that we are, industrially, in a situation much like the European situation from 1935 to 1939; an impending war to the death with 'appeasement' as the only, unavailing, policy

Jan 1, 1945