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By Spencer R. Titley

"For his pioneering contributions to the understanding of the geology of porphyry copper systems" Recipient Of The 1997 D. C. Jackling Award SPENCER R. TITLEY Introduction The subject of this lecture, a late century perspective on porphyry copper geology, is one of current interest and importance as the search for these ores remains intense. It is presented in the belief that an appreciation of our present understanding of the subject requires it to be viewed historically, thus providing a basis for evaluating appropriate directions for continued study. At the outset, it is important to note that the technology of mining and extractive metallurgy has developed ore from these low grade orebodies, starting with D. C. Jackling, and has continued to create them as copper grade and price have diminished. But the continued search for them is a geological problem that responds to growing expectations of people and societies; exploration based upon ever increasing knowledge of the habits of the ores has been very successful. This is the story of evolution of geological thought and practice in porphyry ore search across an interval of time beginning with the bulk mining of "low grade" copper ores at Bingham and ending with late Century concepts. "How did we get here?" The lecture concerns the ideas of many different people. The ideas and events discussed reflect a bias on North American thought, where the great low grade orebodies were first recognized as such and where many of the basic geological ideas were developed. A very great number of geologists have contributed to this understanding. In no sense is it meant to minimize the contributions to the story that have evolved in the study and mining of ores of the Andes, whose development and expansion has been nearly synchronous with that in North America - nor to minimized comparable contributions made in the late century from studies of the newer discoveries of deposits in other regions, especially the southwestern Pacific regions. In expansion of this topic, I have found that many important concepts are marked by appropriate publication but some are not, or I have not been able to discover documentation. Many notions appear to have become conventional knowledge without publication, mostly being geological viewpoints developed synchronously from similar observation. Thus, apologies are extended in advance to those whose work I have might have missed and to those unknown to me whose unpublished ideas may have seeped into the pool of common knowledge without appropriate recognition. The analysis here addresses events of two time segments, an older one extending from the developments at Bingham in the early 1900s through the Second World War, ending about 1950: the second period extends from that time to the present. This separation is seen in Figure 1, which traces numbers of publications through the period as extracted from some 700 publications, again with a North American bias, from an annotated bibliography of porphyry copper geology in preparation. During the early period, exploration was "immature" in North America, that is, geologists looked for new districts and sites of the deposits. Outcrops were sought that carried the signatures of former mineralization and regional controls related to structural geology were closely studied. In the later period, North American exploration had "matured" into a study of districts, rather than a search for them. As the studies of these ores intensified during the younger period concommitant with increasing demands for the metal, they did so with a broadened understanding of some habits of occurrence, of hydrothermal alteration, mineral zoning, petrology, and geochemical and geophysical signatures. Outside of North America, search remained "immature" but closely related to the

Jan 1, 1998

The stability of mine roofs in permafrost zones is determined mainly by temperature and ice content. The deformation resulting from creep and temperature dependent physical properties of frozen rockmass is the dominant component of total deformation. Roof bolts can consolidate the roof and control its deformation. In this paper, a finite element model for analysis of the effects of roof bolting in a frozen rockmass is presented. The model includes the variables normally encountered when analyzing the effects of roof bolting in rocks. It also accounts for properties unique to frozen rockmass, creep deformation and the change in Young's modulus with changing temperature. The model shows that, as bolt spacing decreases, there is a trade-off between increased roof stability from increased mechanical support and decreased stability from increased conduction of heat into the frozen roof. This result was expected, and shows that, for a given set of rockmass conditions, including ice content, temperature, particle size, etc., there is an optimum bolt length and bolt density for minimum roof deflection.

Jan 1, 1996

Throughout the 1970s, the US Bureau of Mines rode an ebb tide in Washington political circles. In rapid fire succession, the agency lost its mine health and safety enforcement responsibility (1973), a large portion of its energy research responsibility (1975), and then its fuel statistics functions plus a sizable portion of its coal R&D (1977). By 1978, johnny-come-latelies in the Energy, Labor, and Interior Departments had siphoned away from the Bureau some $125 million in program responsibilities as well as 900 of its employees. The bruising decade came to a close with a Department of Natural Resources proposal that, in its original form, would have scattered the Bureau's responsibilities to the winds. "There is no doubt in my wind," said Lindsay Norman, acting director of the Bureau of Mines (see box), "that were the Bureau to continue down the path it was on, the next step was closing the doors and going out of business." The doors are still open, but erosion of responsibilities had a devastating effect on the resources available to fulfill the Bureau's mission. Devastating, too, in terms of internal morale, considering the Bureau had six directors in a 10-year span. "When the troops are in the trenches and are being shot at," Norman said, "they need a leader-hopefully, a permanent one- that can get them advancing. This is something the Bureau did not consistently have in the 1970s." In September 1978, Roger Markle climbed aboard as director of the Bureau to rejuvenate the 70-year-old agency. He resigned only six months later* but the program Markle set in motion is being carried through by Lindsay Norman. Since Norman's appointment as acting director, he has spent considerable time on the road explaining his agency's redefined goals. At one such stop in Duluth, Norman and his two deputy directors, Charles Kenahan and Mike Kaas, answered the following questions. Lindsay, you were the principal architect in the Bureau's 1979 reorganization. How about a glimpse of what that entailed? Toward the end of the 1970s, after almost a decade of steady dismemberment, we reached what we felt was a critical point in the Bureau's history-we had the choice of redefining and strengthening our organization to meet the mineral challenges ahead, or continuing down the path toward the agency's eventual demise. We felt the Bureau's mission too important to abandon, so in 1978 with Roger Markle as director we initiated a six-month, no-holds-barred intro spection of just what the Bureau should be doing, why, and toward what ultimate national needs. And what did this self-reflection reveal? That there is, indeed, a unique federal role for the Bureau of Mines-that of a lead agency for influencing mineral decisions and pioneering tomorrow's technologic advances. Don't confuse us with policymakers, we're not. But we are policy analysts; we're scientists, engineers, and mineral professionals who can offer a sorely needed source of objective, accurate information to decision makers in both the public and private sectors. I feel there is no better brain trust in government than the Bureau when it comes to mineral expertise-of course, I'm biased. Do I understand you to say the Bureau of Mines is an advocate agency for the minerals industry? We plead no parochial interests, nor ought we, but from our viewpoint a sound minerals industry is extremely important to the broader national goals of security and a healthy economy. US dependence on foreign sources for critical minerals, the increasing noncompetitiveness of some US mineral sectors, and the array of land use issues surrounding mineral-rich lands all have much more serious implications than many otherwise informed people seem to recognize. In your estimation, how vulnerable is the US to foreign mineral suppliers? Let me make a distinction between dependency and vulnerability. The

Jan 4, 1980

By Gregory R. Wagner

As you know, NIOSH is the part of the United States Public Health Service with responsibility for conducting and supporting research leading to prevention and control of occupational diseases and injuries. Some years ago, NIOSH went through a process of identifying and leading occupational health and safety problems in the United States. Candidate problems were evaluated in terms of the number of people affected, the importance of the effects, and how amenable the conditions are to preventive interventions. Lung diseases were ranked first on the resulting list. Diseases from mining continue to contribute substantially to this unfortunate position of prominence. The work of the Generic Center is one of many answers to this critical problem. Although the research is often expressed in terms of dust characterization or dust control, the reality is that high dust levels are much like high blood pressure. No one cares about hypertension per se. We are concerned about the consequences of exposure to untreated high blood pressure--heart disease, kidney disease, and stroke. Similarly, if dusts were truly only a nuisance, there would be little justification for the diverse research program supported by the Bureau of Mines or by NIOSH. But mineral dusts do cause a range of significant health problems: pneumoconiosis, bronchitis, and emphysema. The research supported by the Center is aimed at doing something about them. Within a public health approach to occupational health, we have a hierarchy of interventions. Primary prevention of problems is prevention at the source: solving a problem before it affects a worker. What we call secondary prevention is an attempt to identify health problems at a sufficiently early stage that some intervention will interrupt the disease process or the development of significant impairment. Tertiary prevention refers to rehabilitation of the worker who has already suffered significant loss of function. At NIOSH, and in the Generic Center research programs, the focus is on primary prevention. Basic investigations into those things about specific dusts that promote or reduce toxicity is critical for our understanding of how to prevent disease. Also, the search for engineering solutions to reduce or control dust generation is essential to solving problems of dust over-exposure. But until the engineers create the foolproof safe environment, it will also be necessary to discover better ways to identify the earliest markers of disease. To do this, we must explore and explicate the basic mechanisms of disease through laboratory investigations as well as human observation and physiologic testing. The unique opportunity provided by the Generic Center program and highlighted in this diverse program over the next few days is that these efforts are being carried out in multiple disciplines concurrently. Also, there are periodic small and large gatherings such as this one where investigators have the chance to get together, formally present papers, and informally stimulate each other's progress towards disease prevention. To ignore the potential for this cross-cutting interaction would be a significant loss. To take full advantage of it is potentially revolutionary. I recently pulled out a book I hadn't read since I was an undergraduate. It specifically concerns the nature of intellectual ferment surrounding the development of the concept of a sun-centered rather than an earth-centered universe in the sixteenth century. The book is about more than developments in astronomy: it is a discussion of the nature of scientific revolutions. Scientific revolutions result from the brilliance, insight, and good fortune of the few superimposed on the evolutionary work of the many. They both cause and reflect significant itellectural and social ferment. For example, the revolutionary work of Copernicus in recognizing the limitations of the concept of an earth-centered universe reflected contemporaneous developments in optics, mathematics, physics, economics, and philosophy.

Jan 1, 1991

By Keivan PakIman, Maziar Pasdarpour

Transportation tunnels are highly sensitive to ground movements and are required to be stable and secure for safe operation. In urban areas, the interaction between tunnels and adjacent piles, which are widely used to support buildings and other structures, requires careful consideration. The seismic response of tunnels may vary depending on the lateral stiffness and strength of the tunnel walls, while the axial loading and seismic impact of adjacent piles may cause soil displacement and stress changes that can damage the tunnel lining. As a result, tunnel owners often impose strict limits on the design of new piles lying close to existing tunnels including maximum allowable tunnel deformation, stress change limits, and minimum tunnel to pile separation distances. This paper describes a numerical analysis of the inuence of the axial loading and seismic impact of bored pile foundations on subway tunnels, undertaen using the nite element software laxis D. ased on the results of the numerical analysis, the paper suggests a more realistic and less conservative approach for designing piles in close proximity to transportation tunnels. INTRODUCTION The interaction between tunnels and adjacent piles can cause stress changes and displacements in the soil and structures which may adversely impact structural performance and tunnel safety. It is therefore important to take account of relative load transfer and piling conguration when designing new piles in

Jun 23, 2024

By Earl Cook

Introduction Men like physical power because it gives control over nature and over other men. Physical power comes in two common forms: explosive and non-explosive. In both forms, the most powerful devices yet invented make use of nuclear energy: on the one hand, the hydrogen or fusion bomb, and, on the other hand, a nuclear power plant. For some nations, nuclear power offers a measure of independence not otherwise available in a time of diminishing and unevenly allocated fossil fuels. Consequently, it has great attraction. Unfortunately, the application of nuclear energy (especially fission energy) to either explosive or electrical power entails a singular risk, that of injury from ionizing radiation, both natural and induced; this risk is found in all stages of the nuclear-fuel cycle, from mining of fissionable materials to the disposal of wastes produced in the "burning" of nuclear fuels. The health costs of nuclear power were not fully assessed in the early stages of the development of nuclear technology and some of them were not properly guarded against, either in the USA, which led the world into the nuclear age, or in Canada, which followed an independent path. What I shall do in this paper is to sketch the history of nuclear regulation in our two countries, to point out what I consider similarities and differences, and to suggest that regulatory history, as perceived by a concerned public, has a great deal to do with what is possible today and probable tomorrow, in other words, with public acceptance or rejection of the nuclear option. The U.S. situation As we sow, so shall we reap. In the USA, further expansion of the nuclearpower industry has been almost stymied by government actions that reflect mounting public concern. There is no national storage facility for spent reactor fuel and it has been decided not to reprocess it; consequently, existing power plants are about to choke on their own wastes. Since the Three Mile Island accident, no new nuclear plants have received operating licenses, although several are ready to start up. The uncertainty of future government action has caused the abandonment of plans for a number of new nuclear plants. In addition, many research projects related to medicine and agriculture, which produce low-level radioactive wastes, are about to be shut down for lack of licensed disposal facilities. Some would maintain that this situation has come about because of the low benefit-to-cost

Jan 1, 1980

By Nobuharu Isago, Atsushi Kusaka, Kosuke Kawata

"Rock tunnels suffered severe damage from recent large earthquakes in Japan, despite the empirical knowledge that tunnels tolerate earthquakes better than surface structures. Seismic design for rock tunnels have therefore become a fascinating subject for many tunnel engineers. However, even basic behavior, including deformation mode and loading magnitude for hard-rock TBM tunnels and conventional ones during earthquake, has not been fully understood due to lack of actual seismic data; while EPB and slurry TBM tunnels take account of seismic design in Japan if needed. This study conducted a dynamic measurement in an actual road tunnel constructed in rock. The strongest aftershock of “the 2011 off the Pacific coast of Tohoku Earthquake” (Mw = 7.1) occurred during the measurement, providing precious data to examine deformation mode of the tunnel. Considering the acquired data, numerical analysis was also performed to calculate loading magnitude to cause fatal fracture of tunnel lining during earthquake.INTRODUCTIONLarge earthquakes can pose serious risks even for rock tunnels, as evidenced by large earthquakes in the past. In the large earthquake in Japan in 2004 (Mw = 6.6), some tunnels suffered severe damage including collapse of their permanent lining (Mashimo 2005), even though the tunnels were constructed in ordinary ground conditions except for fault, fracture zone, portal area, etc. To mitigate such risks, mechanical behavior of tunnel lining during earthquake should be clarified; however, even basic mechanical behavior including load-bearing capacity of the tunnel lining against earthquake is not fully understood.Numerous damage modes were actually observed due to various ground conditions (eg. Wang et al. 2001; Mashimo 2005). Among them, major tunnel damage caused by earthquakes can be grouped into three main modes as shown in Figure 1, excluding extremely unusual conditions such as a tunnel located on a stratum boundary where the stratum stiffness varies significantly. TYPE-I shows flexural failure or crack by bending moment at shoulders; TYPE-II indicates compression failure or flexural compression failure at crown; and TYPE-III illustrates compression failure at sidewall, mainly observed on tunnel that was constructed using steel ribs and lagging method. These damage modes, Type-I, II and III, are predominantly caused by shearing, horizontal compressing and vertical compressing deformations of the surrounding ground, respectively (Kusaka et al. 2011; Asakura et al. 2001)."

Jan 1, 2016

In 1991, US mine production of barite decreased 3.4%. Barite consumption, sold or used by grinding plants, decreased by 11.7%. Imports also decreased by 15.4% over 1990. World mine production increased I%, according to the US Bureau of Mines. The value of domestically produced barite, f.o.b. mine, increased 3.3% according to the Bureau. The declared value c.i.f. US port of all imported crude barite during 1991 increased from $40.61/t ($36.84/st) in 1990 to $42.35/t ($38.42/st), the Bureau stated. Nevada was the leading producer of barite with 78% of the total, followed by Georgia and Missouri. It is estimated that 75% of the domestically mined barite was used as a weighting agent in drilling fluids. The remaining 25% was used in barium chemicals, glass or as a filler. Most of the production from Missouri, Georgia and Tennessee was used in the non-oilfield sector. Of the total barite used by grinding plants and chemical manufacturers, it is estimated that 93% was used in drilling fluids. The remaining 7% was in the non-oilfield sector, including barium chemicals and fillers in paper, plastics and glass. Tonnage consumed in the drilling fluids market decreased due to the lower average rig count during 1990. The average number of rotary rigs operating was 860. That was 14.9% less than the 1990 average of 1010 in the US. Crude barite imports were 138 kt (152,000 st) less than 1990 or 15.4%. Imports accounted for 70% of the (ap¬parent) barite consumed in the US. During 1991, China continued to be the leading exporter of crude barite ore to the US with 85.1 %. India followed with 14.8%. About 97.5% of the imported barite ore was used in the oilfield sector. Ground barite imports decreased from 56.7 to 46.2 kt (62,500 to 51,000 st) 1991. Mexico was a major exporter to the US, accounting for 75.3% of the total ground barite imports. Canada shipped 23.7%, while other countries accounted for less than 1 %, primarily for the nonoilfield market. During 1991, the number of grinding plants supplying the drilling fluids market along the Gulf Coast was reduced from 12 to 10. Baroid Drilling Fluids completed its mining program at the Rossi Mine near Dunphy, NV.

Jan 1, 1992

By Rush H. Spedden

Antoine M. Gaudin was a vigorously creative man and throughout his career an internationally respected leader of his chosen profession of mineral engineering. To his professional colleagues and clients and to his former students he was both "Professor Gaudin," their wise, inspiring, and enthusiastic teacher, and "Tony," their warm and beloved personal friend. Thus, his teachings and his unique inquisitive-creative approach to problems live on and grow in the accomplishments of his students. Antoine Gaudin was born at the turn of the century in Smyrna, Turkey, where his father was general manager of a French-owned railroad. It was there that he spent his earliest years, literally in the shadow of classic marbles from diggings at the site of Aphrodesias, which his father had rediscovered. From this, Tony developed an appreciation of the arts. He eventually surrounded himself with art treasures; he reveled in the beauties of nature, and he cherished his choice collection of rhododendron and azaleas. His artistic traits led him to take up painting when his daughter, Elinor, sought his help in blending her tints for a water color. In typical fashion he was not satisfied until he had become adept with pastels in capturing the muted tones of distant landscapes and the technical properties of light and color. Unfortunately not many paintings were produced. His paternal grandfather was Marc-Antoine Gaudin, for many years secretary of the Academie des Sciences in Paris, and a well known chemist and mineralogist whose primary interests included the synthesis of precious stones. In an autobiographical sketch written in 1939, Dr. Gaudin recalled: "As a child I saw many of the original synthetic sapphires and rubies which my father had inherited. This, coupled with my father's avocation of mining ventures and archaeology, early decided that I would become connected with the mineral industry." One can speculate that the archeological activities of his father, the mineral systhesis experiments of his grandfather, and his own early studies of mineralogy and geology formed a base from which his special talents as an experimentalist were to develop. Laboratory research under Professor Gaudin's personal guidance was often an intensive, fast- moving, and exciting experience--especially to a new graduate student. First of all, Professor Gaudin was a highly skilled observer with seem-

Jan 1, 1976

By AMIR EHSAN KIANFAR, Moritz Ziegler, TOBIAS HARTMANN, ELISABETH CLAUSEN

Accurate positioning information is a central step in the process of increasing automation and digitalization in the mining industry. Underground mine environments are prime examples for GNSS-denied environments that pose several additional challenges for the employed indoor positioning system (IPS). This work presents an ultra-wideband (UWB)- based system specifically tailored for underground mine environments. Initially, the UWB technology is reviewed and basic concepts of IPS are explained. Both software and hardware are described in detail, including positioning algorithms, electrical circuitry and the mining-compatible enclosure. Finally, the results from field tests in an underground mine are presented and positioning performance and the influence of dilution of precision (DOP) on positioning results are empirically evaluated. The results show that the localization errors are mostly below 1 m. Individual zones of high localization errors are suspected to be caused by noise interference. Significant DOP influence due to the mining drift geometry can be confirmed. The system shows promising localization results for different mining applications, while influences negatively impacting the accuracy are presented as items for future research.

Jan 1, 2024

By Larry J. Hughes

Ground-based electrical geophysical techniques have be valuable for three indirect exploration strategies: "tracer" sulfide mineralization, 2) mapping structure with or controlling mineralization, and 3) mapping proven to 1) mapping? associated alteration zones. When sulfide mineralization is associated with gold, it often can be mapped using induced polarization (IP). This technique can detect pyrite in amounts as small as 0.2% by volume, and in some cases can distinguish pyrite from anomalies due to graphite and clays. A case history illustrates mapping sulfides in a shear zone. Structure and alteration mapping are often the domain of controlled source audio-frequency magnetotellurics (CSAMT) due to the superior lateral resolution and depth penetration of this technique. Typical CSAMT targets include silicified sediments and volcanics, faults, brecciated zones, argillic alteration, clay and graphite horizons, and certain lithologies. Examples of mapping silicification and mapping epithermal alteration are presented in CSAMT case histories over Cannon mine in Washington and Hishikari mine in southern Japan. In our experience, four things are needed to use geophysics effectively in precious metals exploration. First, the explorationist must correctly identify the exploration stage at which the geophysics is most useful. Second, the explorationist must clearly define the types of "tracer" mineralization, host geology, or alteration which need to be defined by the geophysics. Third, the right electrical technique needs to be applied to the problem to provide the best chance of success. Fourth, the explorationist must be willing to commit adequate finances to do the geophysics properly. With careful adherence to these principles, geophysics can greatly enhance exploration success while reducing the total cost of exploration.

Jan 1, 1989

By H. E. Bonner

The recovery of fine coal has historically had limited success due to the intimate clay association on the surfaces of the coal particles. This clay presence has detrimentally affected conventional beneficiation techniques resulting in a recovered product containing unacceptably high concentrations of ash and moisture. An ultrasonically activated tray that operates in a continuous fashion has been developed that separates the clay film from each particle's surfaces. This separation is of sufficient duration to allow conventional beneficiation techniques to be utilized more efficiently.

Jan 1, 1989

By F. Montgomery Lyon

Pyritic sulfur in coal occurs as discrete mineral particles, and its liberation and physical rejection is the primary target for coal desulfurization. An acceptable solution to the pyrite removal problem from fine coal is not found in the standard methods of coal cleaning such as jigging, heavy-medium separation, tabling, and hydro-cycloning. Although fine coal is an ideal size for froth flotation, this method, as currently practiced is also unsuitable as the fine pyrite usually floats with the coal. One possible solution to this problem may be the froth flotation of pyrite from coal. This reverse flotation scheme would have the major advantage of removing both free pyrite and locked pyrite-coal combinations. With this possibility in mind, we have, as a first step, compared the flotation and adsorption. characteristics of an ore-pyrite and coal-pyrite with potassium-ethyl-xanthate as a collector 1 Related Research. The action of ethyl-xanthate on coal has been studied 2 by Horsley. He measured the contact angles of coal in distilled water and in the presence of purified ethyl-xanthate. The results indicated that the xanthate was not adsorbed by the coal. Additional contact angle data were obtained to determine the effects of cupric, ferric, and ferrous salts on the system. Then either the ferric or cupric salts were in, solution with the xanthate, there was an increase in the natural contact angles of the coal. This indicated that these heavy metal ions activated the flotation of the coal with xanthate. However, ferrous iron did not act as an activator. Horsley stated that the most attractive explanation was that the xanthate is oxidized to dixanthogen in the presence of the ferric and cupric ions.

Jan 1, 1971

By Mirza Muhammad Zaid, Nana A. Amoah, Ping Chang, Guang Xu, Ashish R. Kumar

The key takeaway of this study is the significant improvement in dust protection for roof bolter operators in underground coal mines. The optimized canopy air curtain (CAC), with a redesigned two-level manifold system, provides uniform airflow distribution that effectively reduces dust exposure. By enhancing the protection of operators from harmful respirable coal and silica dust, this technology can reduce the risk of diseases such as coal workers’ pneumoconiosis (CWP) and silicosis. The application of this optimized CAC design in real-life coal mining operations can dramatically improve worker health and safety by minimizing dust-related exposure, ensuring compliance with industry regulations and prolonging the lifespan of mining equipment by reducing dust accumulation.

Dec 1, 2024

By Jack O?Hearn

A liquid and solid waste management plan for an operating uranium ore processing mill was developed to efficiently and effectively dispose of existing solid wastes and related, affected surface and ground water resources. The goal of this management plan was to achieve satisfactory clean up of these existing wastes ad their by-products as well as to prevent similar situations from occurring in the future. An existing, modern system of synthetically lined tailings ponds, constructed after many years of mill operations, now provides an approved site for the disposal and containment of waste streams currently generated by the mill. This system was thought to be readily adaptable to serve as a key element of the waste management plan. The potential presence of extra capacity in these ponds could eliminate or reduce expenditures for new facilities required solely for proper management of liquid and solid wastes generated by operations prior to construction of the modern tailings ponds as well as for a range of anticipated future operations.

Jan 1, 1984

By M. A. Gibson

Ilmenite-rich lunar deposits can be converted to liquid oxygen to support lunar base operations and space transportation propulsion needs by a Carbotek-developed process. Iron oxide in ilmenite is reduced at elevated temperatures by hydrogen in a fluidized-bed reactor to water vapor which is electrolyzed to product oxygen and recycle hydrogen. Reaction rate, thermodynamic equilibrium, and lunar-gravity fluidization behavior are key factors which have been considered. Fluid-solids behavior has been modeled from data taken at lunar gravity conditions aboard NASA KC-135 flights. Large-scale pilot plant operations are planned to complete the development.

Jan 1, 1991

Caterpillar unveiled a new dozer, the new Cat D10T2 dozer, that builds on the success the company has had with its D10T model. The newest version of the dozer includes refinements to its power train, automated controls and structures. The result, the company said, is high productivity with superior fuel efficiency, reliable operation with long-lived structures, as well as enhanced access for service technicians and operators. The D10T2 uses the latest load-sensing hydraulics technology combined with Cat advanced engine controls to maximize the amount of material moved for every drop of fuel burned. Improved filtration protects the fuel system, hydraulic system and power train oil system to help ensure high reliability and minimal machine downtime. Refined large structures, such as redesigned track roller frames, deliver longer service before rebuilds. Improved access and egress features enhance safety and productivity of technicians and operators, and optional powered access systems and platforms enable configuring the D10T2 for the site. Caterpillar offers the D10T2 with two variations of the Cat C27 engine with ACERT Technology. One version is U.S. Environmental Protection Agency (EPA) Tier 4 Final certified, and the other is capable of achieving emission levels equivalent to EPA Tier 2 standards. Both engine configurations produce net power of 447 kW (600 hp) in forward gears and 538 kW (722 hp) in reverse gears. The engine controller automatically adjusts power output based on the direction of travel. With the new system, the D10T2 has about 20 percent more power in reverse compared to its predecessor model. The result is faster cycle times and greater productivity in certain applications. The D10T2 is suited for a variety of applications including mining, heavy construction and bulk materials handling.

Mar 1, 2014

By C. E. Jordan

The Bureau of Mines has investigated the fundamentals of fatty acid/fuel oil conditioning for improved flotation selectivity. Both conditioning time and intensity can provide optimum flotation selectivity as well as good recovery. Traditional conditioning seeks to optimize conditioning parameters with subsequent recovery of the hydrophobic mineral. In the fatty acid/fuel oil system many silica gangue particles are also rendered hydrophobic by the flotation collector. Fundamental studies have shown that particle-particle collisions transfer the collector reagents selectively to the mineral surfaces with the highest affinity for the reagent. This mechanism deactivates the gangue particles while increasing the collector reagent loading on the selected mineral. The degree of this transformation is directly related to the number of particle-particle collisions which can be controlled through conditioning time or conditioning mixing intensity.

Jan 1, 1995

By John MacDonald

An unstable economy has shown businesses what the mining industry has known for decades ? a successful business location today may not succeed in the future. Unexpected expenses, natural events and workforce changes have a big impact on the costs of production. To help focus production and maintenance budgets, mining executives are increasingly turning to production metrics to make key decisions. Role of mine and mill data Companies employ a variety of information systems to allow employees to accomplish their operational tasks, and each worker is focused on the metrics, or key performance indicators (KPI), for his or her individual function. For example, machine operators monitor throughput and cycle time to keep the machines running continuously and to meet daily production quotas. Meanwhile, the maintenance teams monitor machine performance, overall equipment effectiveness (OEE) and meantime between failure to predict and help prevent downtime.

Jan 1, 2013

By RICHARD A. THOMAS, Liming Yuan, Lihong Zhou, DAVOOD BAHRAMI

Mine ventilation simulation software has become an essential tool for the mining industry to design and manage mine ventilation operations. Building a well-calibrated mine ventilation network is time consuming, however, and requires great effort. In the last several decades, the mining industry has seen a steady increase in the use of air velocity sensors to monitor airflow and detect unexpected abnormal airflow in some key locations in underground mines. The present research work was carried out to explore the possibility and methodology of calibrating a ventilation network model using atmospheric monitoring system (AMS) data on a routine and ongoing basis.

Aug 1, 2022