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By C. L. Reichardt

Mining companies are increasingly looking to the developing world for the next generation of mining projects, often in countries that have little or no previous history of large-scale mining. One of the major challenges for such projects is hiring?and retaining?personnel that have technical skills and experience in mining-related disciplines. Staffing a mine with an expatriate workforce is neither cost-effective nor sustainable, and many countries now insist that mining companies ?transform? the profile of their workforce to more closely mirror the demographic profile of the host population. The need to nurture mining-related skills in emerging mining nations is not solely limited to the workforce: there are also pressing economic and sustainability imperatives to develop capacity within local service providers such as consultants and contractors, as well as to facilitate informed engagement between mining companies, government and civil society. However, few educational institutions in emerging mining nations currently have the ability to offer practical training in mining-related disciplines. Local employees who are sponsored by companies to develop their skills through international study maybe impeded by language and cultural barriers, and may also be taught using course content that is of limited relevance to the specific challenges of their future working environment. This paper addresses the challenge of skills development and retention in emerging mining nations and uses examples from sub-Saharan Africa and the Asia Pacific region to explore practical means of developing capacity in mining-related disciplines. It examines the need for companies to implement strategies to develop local technical capacity in countries where they envisage a long-term operational future and also highlights the need to foster partnerships between academia, developmental institutions, mining companies, governments and civil society to establish the critical mass of mining-related skills required to nurture the development of a sustainable mining industry.

Jan 1, 2009

By C. C. Miller, A. R. Belyea, C. H. Herty, E. B. Burkart

The removal of sulfur from steel has been studied by many investigators, but the quantitative relationships between the factors involved have not been determined. This is undoubtedly due to the number of variables encountered in practice, an attempt to study any one reaction or relation being affected by other reactions the relative importance of which cannot be estimated. The factors that affect the extent of removal of sulfur in the basic open-hearth process are generally considered to be: 1. Basicity of the slag: (a) Iron oxides in the slag; (b) carbon in the metal or carbide in the slag; (c) temperature. These factors affect the reactions: FeS + CaO = CaS + FeO FeS + CaO + C = CaS + CO + Fe. 2. Amount of sulfur in the gas. 3. Amount of manganese in the metal. The factors which affect the rate of removal of sulfur include, in addition to these: 4. Fluidity of the slag: (a) Normal changes in fluidity with temperature; (b) changes in fluidity because of the addition of special reagents such as fluorspar. 5. Agitation of the bath. Within the past two years, two papers have been presented dealing with the influence of sulfur in the gas on slag and metal. Nead' has shown that if a gas high in sulfur be used for heating, the metal and slag will absorb sulfur. Whitely2 concluded from his experiments that if a

Jan 1, 1925

By W. Dan Walker

In recent years the Federal Bureau of Mines tested and approved four new types of self-contained breathing apparatus and a facepiece designed for use with the McCaa 2-hour self-contained oxygen breathing apparatus. The Bureau also developed and perfected a battery-powered lifeline telephone for use in mine rescue and recovery operations. Some of this equipment is described in Bureau of Mines Information Circular 7413.4/ This publication is a revision of information Circular 7413 and presents pertinent information on more recently developed mine rescue equipment. The breathing apparatus described herein are 1/2- and 3/4-hour sell-contained types of much simpler design than the conventional 2-hour self-contained oxygen breathing apparatus ordinarily used by mine rescue crews; however, it is just as important to select rescue crews carefully and to train them properly in the use, care, and limitations of the newer types of apparatus as well as the older, established types, if the newer types are to be used safely. The Bureau of Mines recommends that 1/2- and 3/4-hour self-contained breathing apparatus be used only as auxiliary equipment in mine rescue and recovery work and that the capabilities and limitations of the apparatus should be well understood by those who wear the equipment.

Jan 1, 1957

By G. L. Mowrey

In addition to developing various types of coal interface detection systems, the U.S. Bureau of Mines is actively involved in developing a coal rib thickness monitoring system for high wall mining applications. One particular system that appears to show promise uses a ground-penetrating radar system to detect the coal-air boundaries of coal ribs. Based on preliminary laboratory and field tests, results indicate that this method can be applied successfully in highwall mines to maintain a constant rib thickness. The coal seam should be relatively clean in the vicinity of the antenna (e.g., have minimal partings or dirt bands) for best results.

Jan 1, 1995

You have been involved with research activities in froth flotation and size reduction. What do you think the future holds for these technologies? Froth flotation and size reduction are essential processing steps common to almost all current mineral-processing operations. The most significant recent advances in both of these technologies have been in the increased size of equipment and in some alternative machine designs, such as the column cells and the high-pressure roller mills. I believe that the next major area of improvement in size reduction will be at least partially driven by an improved awareness of controlling the conditions that influence the efficiency of particle breakage. This would include factors such as water-chemistry influences, the influence of fines from classification, chemical grinding additives and better rheology control. In froth flotation, significant changes are currently taking place in the plant use of frothers. Also, there will be an increasing number of new collector chemistries for certain types of flotation, such as with oxide minerals, oxidized mineral recovery in sulfide systems and improved selectivity with certain sulfide mineral systems. You have been active in implementing new engineering technology in industry. What do you think will be the technological future of mineral processing? Being involved in the invention and industrial implementation of new technology has been one of the most positive experiences of my career. I also have had the unique experience of working in the chemical and petroleum industries as well as in mineral processing. In my opinion, the future of mineral processing will be an exciting, wonderful work area in which to be involved. The development of new technology in minerals processing offers a special challenge compared, for example, to that of chemistry or chemical engineering. In successful industrial innovation involving minerals, having a sound theory is not enough. Instead, what is required is a valid blend of a good idea, meaningful laboratory characterization and, most key, the experience necessary to adjust the plant in such a way to incorporate the idea. The complexity of engineering systems that contain solids, liquids and gases, as well as highly variable natural mineral properties, means that nothing new comes easily. In some cases, it has been difficult to explain how processes practiced in industry for decades actually work, in terms of physical and chemical fundamentals. On the other hand, when a new idea is successfully implemented, the economic and professional returns can be very rewarding. I know of no more challenging field of engineering than minerals processing. What is your view of the future of the minerals industry in general? The need for minerals, metals and coal will be with us for decades to come. In many aspects, the minerals industry became global much earlier than some of the other industrial sectors that are currently experiencing globalization. I believe that fair international competition is beneficial to the users of minerals, metals and coals and to those involved in producing such materials. The key word here for a global economy to work is "fair." So the various playing fields involved such as finance, profit return, regulation and labor should be relatively level for all the players involved. Competition is an amazing driving force for innovation. This has been true in the minerals industry during the last few decades. The mining industry is producing more at less cost per unit than ever before in our history. I anticipate that this trend will continue as long as the global political situation remains relatively stable.

Jan 1, 1997

By K A. Campbell, K A. Rodgers

The Plumduff sinter occurs at Whenuaroa, near Puhipuhi, approximately 30 km north of Whangarei. It is one of three residual sinters in the southern portion of a mid- to late-Pliocene geothermal system. The deposit consists of many large sinter breccia boulders, including rudrocks (coarse breccias), scattered around the flanks and summit of the small conical hill of Plumduff. Three types of sinter breccia occur: (i) rudrocks consisting of large, angular to sub-angular clasts of layered sinter up to 0.8 m across, as well as smaller clasts of sinter (20 - 100 mm dia), and fragments of stromatolitic structures; all clasts are supported in a matrix of microcrystalline, transparent to translucent to milky quartz; (ii) fragments of layered angular to irregularly mottled sinter of white to grey or bluish hue supported in a translucent to opaque silica matrix; (iii) smaller, matrix-supported breccias with clasts both partially surrounded and/or penetrated, by a clay-like weathering rind, and sinter conglomerates with rounded to oblate clasts. Three principal types of fabrics constitute the bulk of the sinter: (i) stromatolites, including columnar, palisade and filamentous networks, showing progressive silicification, in fenestral, tufted to clotted fabrics; (ii) peloids and pisoids; (iii) plant-rich facies in which various silicified plant species occur in a silica matrix. All fabrics have counterparts in hot spring deposits in the Taupo Volcanic Zone formed at temperatures from 75¦C to 35¦C. Also present is steam-condensate-produced alteration: kaolinite and alunite as well as boulders of quartz lattice texture. Cinnabar only occurs in sinter on the north and south central slopes of the hillside. No quartz veins or geyserite were recognised.

Jan 1, 2001

By J. Gunaselvam

This article deals with an investigation into the specification and use of appropriate seating systems to reduce whole-body vibration (WBV) exposure in typical vehicles used in the SA mining industry. The EU Directive EU/44/2002 to be legislated in 2005 in European countries, provides legal and economic motivation for this project. The criteria for seat selection can be condensed to the requirements in the directive, which mandates an action level of 0.5 m/s2and a vibration exposure limit of 1.15 m/s2 for an equivalent 8-hour daily exposure period. As part of this study six suspension seats, which the manufacturers claim satisfy the requirements in ISO 70966, were tested to determine the most suitable seat for an articulated dump truck. Six test subjects, three ?light? and three ?heavy? as specified in ISO 70966, were used to estimate the seat transmissibility functions in the vertical direction of the six different suspension seats. Transmissibility functions were measured in the laboratory with two excitation levels of 1 m/s2 and 2 m/s2 r.m.s. in the 0.5?30 Hz frequency range, as well as one spectrum approximating the EM5 spectral class. SEAT values were calculated for road vibration data measured on a typical articulated dump truck. A set of seat selection guidelines that can be followed by vehicle manufacturers and suppliers, procurement officers and and the technical staff on a mine is proposed in this article. It is recommended that additional studies of the use and operating conditions of seating systems in the SA industry, as well as an epidemiological survey be commissioned to gather additional information on this subject. Nomenclature ADT Articulated dump truck DSTF Dynamic seat testing facility EM1 Frequency spectra associated with earth moving equipment (?articulated or rigid frame dumper?) according to ISO 7096 EU European Union ISO International Standards Organisation PSD Power spectral density r.m.s .Root mean square SEAT Seat effective amplitude transmissibility WBV Whole-body vibration

Jan 1, 2005

By Eugene A. Dolecki

This final report describes the work accomplished under U.S. Bureau of Mines Contract #H0242011 - "Feasibility of Automated Rail Haulage Systems in Underground Coal Mines." The report outlines the base for the development and evaluation of automated rail haulage systems in terms of the service requirements for haulage systems in underground coal mines, and of the performance of existing haulage systems. A generalized automated rail haulage system concept is defined. A safety impact analysis of automating the mainline portion of the underground system indicates a 50% reduction in injuries and fatalities. A cost effectiveness (over the total life cycle) study for the system indicates a cost benefit can be obtained from implementing an automated rail system. The design specifications for the total automated rail haulage system - including subsystems and components -are developed, and the equipment types and general design approaches evaluated, with selections outlined. A detailed conceptual design for a prototype automated system is described. Conclusions and recommendations are presented, and a program plan devised for implementing a proto-type automated rail haulage system demonstration in an operating underground coal mine by 1980.

Jan 1, 1976

By W. L. Thayer, K. A. Jonasson, R. D. Coleman, J. D. Hazlett, C. E. Capes

"Loss of coal fines in reject slurries limits the yield of coal cleaning operations. Difficulties in handling fines also limit the extent of physical cleaning in treating coals with finely-disseminated impurities. Selective oil agglomeration allows even extreme fines to be processed and offers some novel approaches for coal cleaning and utilization.The oil agglomeration process for the recovery and beneficiation of fine and ultrafine coal has now been commercialized by the Chemical Engineering Section/Chemistry Division of the National Research Council (NRC). This paper describes these activities to apply oil agglomeration and related fine coal technologies on an industrial scale. Pilot plant and large scale results are described, as well as aspects of agglomerate utilization in both wet and dry form."

Jan 1, 1988

By J. C. Stankus

Accurate evaluation of stress and geological conditions is critical to ground control design in underground openings. For a slope entry, the problem is more difficult because a slope will transverse through many different types of strata. Over the past three years, Keystone Mining Services, LLC, an affiliate company of Jennmar Corporation, has developed a new methodology designated the ?Stress, Geologic, and Support Design System (SGSsm)?. This patent pending method analyzes the stress, geology, and support design for a mine slope. It has been successfully applied in various new slopes across the United States. This paper will detail the main concepts of the methodology including: (1) Analysis of stress and geology and identification of strong, fair and weak zones along the slope; (2) Primary and supplemental support design; (3) Long term support design in the form of steel square sets or arches, and (4) Validation of the support design utilizing advanced finite element computer modeling.

Jan 1, 2011

By Alexander May

The Bureau of Mines conducted studies to determine if phosphogypsum, a waste material from the processing of phosphate rock, contains hazardous toxic materials as defined by the Environmental Protection Agency (EPA) and whether leaching of these toxic materials and radium may occur. Samples of the phosphogypsum stockpiled material were evaluated using the EPA extraction procedure, atomic absorption, neutron activation, x-ray diffraction, and chemical and physical means. Radiological tests performed used both the germanium-lithium and emanation methods. The data show that the phosphogypsum stockpiles are not hazardous toxic waste as defined by EPA criteria. Trace elements and radium are not leached from the phosphogypsum stockpiles. Absorption of trace elements and radium by phosphogypsum is the major reason for their not being leached. The standard error of measurement of radium concentrations was 4.7 pCi/g.

Jan 1, 1983

By R. S. Dean

[Methods s of preparing the manganese metal that has been used in chemical and metallurgical investigations have passed through a cycle. Most of the investigations made e before the turn of the century, used Moissan's pyrophoric man manganese.3/ This material was made b; electrolysis into a mercury cathode and distillation in vacuo. The material was essentially pure, and investigations in which it was employed (with proper precautions against oxidation) led to accurate results on tie intrinsic behavior of metallic manganese.]

Jan 1, 1941

By Peter G. Groer

The commonly used exact methods (1-2) to determine the WL measure the total a activity or the total number of a counts during three preselected time periods. Due to the half-lives involved (TRaB = 26.8 min, TRaC = 19.7) I these methods take 3S minutes to complete the a activity Ra measurements. Methods using the total a counts, obtained at times less than about one RaB half-life after the end of sampling run into statistical 214 problems. These methods are almost blind to RaB (Pb214) as a consequence of its relatively long half period (see above) and the fact that RaB is a ß emitter. The way out of this dilema is to measure RaB directly through its ß activity. Since RaB's daughter Rae (Bi214) is also a ß emitter, the two f3 spectra have to be separated to obtain RaB alone. How this is accomplished 1s described in subsequent sections describing the theory of the IWLM and its calibration. 2.0 THEORY The IWLM samples air for two minutes and counts this airs ample for two minutes starting 3 sec after the end of the sampling period. The instrument has three channels. The lower a channel, the upper a channel, and one ß channel. The total RaA counts observed are accumulated in the lower a channel, the total RaC? counts are stored in the upper a channel. The total ß counts from RaB and RaC are recorded in the ß channel. These three quantities are functions of NA, NB, and NC, the unknown concentrations

Jan 1, 1975

By M. Mabuza

Two Rivers Platinum Mine (TRP) is a 55:45 joint venture between African Rainbow Minerals and Impala Platinum, respectively. TRP is situated on the farm Dwarsrivier 372KT, in the southern sector of the eastern limb of the Bushveld Complex. Dwarsrivier is underlain by rock formations of the Critical Zone (Winterveld norite-anorthosite) and the Main Zone (Winnarshoek norite- anorthosite). Two economically significant PGE-bearing layers namely the Merensky Reef and the UG2 chromitite are found within the upper Critical Zone. These are approximately 140 m vertically apart, separated by a series of barren norites and anorthosites. At Two Rivers Platinum, only the UG2 chromitite layer is currently being mined for PGEs. The UG2 sub-outcrops north/south along the Klein Dwarsrivier river valley with a very gentle dip to the west of 7º?10º. At Two Rivers the UG2 averages about 120 cm in thickness, overlain by a waste pyroxenite parting about 20 cm thick, above which is a leader seam about 20 cm in thickness. The mineable cut consists of the leader seam, the waste pyroxenite parting, the UG2 chromitite layer including 25 cm of pegmatoidal pyroxenite footwall, below the UG2 reef to a minimum of 185 cm trackless mining cut. The mining method is a mechanized bord and pillar layout, which will yield a total of 185 000 tons at full run of mine production from the underground UG2 mine.

Jan 1, 2007

By W. G. Sandell, L. C. Bauerle, K. C. Dean

"INTRODUCTION As a part of the wartime activities of the Bureau of Mines, metallurgical services were extended to other Government agncies engaged in purchasing and stock-piling some of the more critical and strategic materials. At the request of Dr. Alan M. Bateman, special representative of the Metals Reserve Company, metallurgical studies were made on three samples of oxide tin ore from, the States of Zacatecas and Guanajuato, Mexico. The samples were submitted for testing by A. Porraz of the Financiera Miners, S. A., institution Financiera, Edificio Guardiola, Despachos 500-507, Mexico, D. F.The samples as received were marked Nos. 1, 2, and 3 and described as follows:Sample 1. - Origin: Mining camp ""El Naranjo,"" municipality of Sombrerete, State of Zacatecas, Mexico. This sample was partly concentrated by washing and as received was all minus 10-mesh in size.Sample 2. - Origin: Deposits in Sierra. Fria and Juan Cherey, municipality, of Jerez,State of Zacatecas, Mexico. This sample represented run of-mine ore.Sample 3. - Origin: Mine ""La Frontere, "" Ranch of San Pedro del loya, State of Guanajuato, Mexico. This run-of-mine sample was low in tin content but came from a highly mineralized tin field."

Jun 1, 1947

By Michael W. Neill, O&apos

The engineering profession generally does not accept vibro-driven piles as bearing piles unless their capacities can be verified by restriking with an impact hammer, which significantly reduces the economic benefits of vibratory driving. In part, the concern for capacity development in piles driven by vibration arises out of observations that vibro-driven piles do not develop capacities equivalent to those driven by impact (e. g., Mosher, 1987). Nonetheless, if capacities are predictable, vibratory installation may be more cost effective than installation by impact, due to savings in time of installation, even if capacities are lower than those of impact-driven piles. Throughout the past few decades, a number of attempts have been made to develop capacity prediction methods for vibro-driven piles, mostly along the same lines as methods for impact-driven piles. That is, (1) totally empirical formulae, (2) power balance / power transfer formulae, and (3) "time domain-nonlinear" (TDN) computational procedures such as the wave equation. Some of the formulae have been based partly on field experience, but the majority have been developed from simple theoretical models with parameters evaluated from laboratory studies. Neither these formulae nor the TDN solutions have been systematically checked (or modified) by recording appropriate field data over a variety of site

Jan 1, 1989

By M. Karmis

Surface subsidence is an inevitable consequence of many underground mining operations and has been recognized as such since the fifteenth century. Damage resulting from this phenomenon ranges from simple land settlement to severe structural damage to buildings and has been witnessed in rural (Illinois, Colorado, West Virginia, Virginia, Pennsylvania) as well as in urban areas (Pennsylvania, West Virginia, Illinois, Wyoming). In fact, it is estimated that over 2 million acres of land across the United States have been affected by mining subsidence, of which 140,000 acres are in urban areas (Singh, 1978; Johnson and Miller, 1979). Further, it is estimated that during the next twenty years an additional 1.5 to 2.4 million acres of land will also be affected by mining. Subsidence prevention is not feasible, at least under the existing technologic and economic constraints of underground coal mining. Foreign experience has demonstrated, however, that subsidence can be successfully controlled if an accurate method of predicting ground movements is available. Such techniques have been developed in many coalfields, where it is currently accepted that subsidence can be predicted within ± 20 percent of the actual values. Furthermore, such movements can be translated into anticipated structural failures using established damage criteria, thus enabling appropriate precautionary measures to be implemented.

Jan 1, 1983

By Dan A. Brown

This paper describes a method of conducting rapid lateral loading tests of deep foundations in which the load is applied to the foundation with a time duration of less than one second. For purposes of this paper the loading is applied using a pyrotechnic loading system commonly referred to as Statnamic. However, the method should apply to any lateral loading system which produces a force time history with a loading duration of 20 msec to 1 second. The test provides a measure of the dynamic and static response of the soil/foundation system and must be evaluated as a dynamic loading. Interpretation of the test includes a simple single degree of freedom (SDOF) model which can account for the inertial effects of foundation mass, system damping, and static foundation stiffness. The results of the test measurements are compared with four case histories in which comparative static load test data are available, including pile group foundations and large diameter drilled shaft foundations.

Jan 1, 2007

By C. W. Elder

"INTRODUCTION This report describes a method of horizontal drilling in an oil-producing formation underlying a 400-acre, approximately square plot of land in the Franklin Heavy oil field in Sugar Creek Township, Venango County, Pa. The method, which was developed on two previous projects in Ohio, 3/ consists of sinking a shaft to the bottom of a shallow oil sand and drilling holes in a general horizontal plane outward from the chamber in a pattern similar to that of the spokes of a wheel. The project was undertaken by the Venango Development Corporation in an attempt to find an efficient method of recovering oil from partly depleted sand formations.The Venango Development Corporation is composed of the following oil-producing and oil-refining companies and individuals: South Penn Oil Co., Forest Oil Corporation, Kendall Refining Co., Minard Run Oil Co., Quaker State Oil Refining Co., The Pennzoil Co., Alliance Oil Corpo¬ration, United Refining Co., Franklin Creek Refining Corporation, Canfield Oil Co., Pennsylvania Refining Co., Page Oil Co., Freedom Oil Co., D. W. and D. S. Grant, and J. P. Herrick, C. M. Davison and N. V. V. Franchot. Engineering features of the project were supervised by a committee off three engineers A. J. Saxe, chairman, W. M. Shoemaker, and C. N. Pfohl, who supervised the excavation of the shaft and the drilling of the first two holes by alternately spending a week at a. time at the project. The drilling method was under patent license from Leo Ranney, who served as technical advisor to the Venango Development Corporation; in addition, he furnished the design for the shaft and work chamber."

Sep 1, 1944

Gas-liquid contacting in the packed bed is a common operation in metallurgical reactors. Research has shown that, unlike wetting flow, non-wetting liquid flows in the form of discrete droplets or rivulets. Thus, modeling of the liquid phase as a continuum is in contradiction to the observations. Also, for the non-wetting case, continuum models have failed to describe liquid flow path when the liquid source is a point source. The aim of the current work is to put forward a combined Lagrangian-Eulerian approach to model the liquid and gas flow in the packed bed. Liquid is assumed discrete and modeled using a force balance approach. Gas is assumed to be interpenetrating continua and modeled using k-emodel for turbulent flow. Structured packing is assumed and x- ray imaging technique is used to visualize liquid flow lines in the bed. Simulation results for liquid flow path compared with the experiments.

Jan 1, 2006