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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

By R. K. Young

Producing a sound plant design for a major project requires hundreds of engineers and many drawings. Economical accomplishment of this task is based upon careful and orderly organization of the design team so that at all times there is a complete and workable staff but at no time a surplus of costly talent. This paper will describe the various stages in the development of plant design which normally follow the laboratory and pilot plant investigations discussed in other papers today. An outline of the procedures used in the assembling of a project design group, within an established engineering organization will be presented. Actual procedures may vary according to the size and character of the plant, the special requirements of the owner, and the make-up of the engineering organization performing the design, but most of the points covered will be found to be basic to any plant design project.

Jan 1, 1960

By Keith G. Wallace, Malcolm J. McPherson

In order to model accurately a mine ventilation system in an existing mine, it is necessary to determine the resistance to airflow in all main airways. This is accomplished by measuring the airflow and pressure differential in each airway. Gauge and tube methods have been used to determine pressure drops in ramps and level airways. However, it has rarely been used in evaluating the frictional pressure drop in shafts. Because shafts commonly have the highest pressure loss in mines, it is critical that the resistance of these airways be determined accurately. This paper describes the theory and practice of using the gauge and tube method for determining the pressure drop in shafts. The pros and cons of using this method are discussed as well as a comparison between the gauge and tube and barometer measurement techniques. Case studies showing the accuracy of shaft gauge and tube measurements are also presented.

Jan 1, 1991

By David Loomis

Unlike previous gold mining booms in Nevada's Great Basin, the current boom includes a serious commitment to mine reclamation. Many of the smaller mines began reclaiming in the late 1980s but met with limited success due in part to poor soil characteristics. Public land managers and the mining industry began looking for ways to improve reclamation success. One promising technique is suggested by an ongoing research project using sludge biosolids, the solid residue of municipal waste water treatment. During the 1980s, limited space in landfills led municipal governments to search for alternate ways to dispose of their biosolids. The cities of Reno and Sparks, NR and the US Bureau of Land Management (BLM) searched for ways to combine these needs to everyone's mutual benefit. Yet barriers remained. The federal government had major concerns about potential bioaccumulation of metals and contamination of drinking water from the land application of municipal biosolids. The barriers were lifted late in 1991 when an interagency task force led by the Environmental Protection Agency (EPA) issued a new federal policy on the use of biosolids on federal land. The policy encouraged biosolids as a soil amendment to reclaim degraded minelands and invited federal agencies to develop biosolid pilot projects. In response, BLM enlisted the help of American Resources Corp. (ARC) and the University of Nevada, Las Vegas for a pilot study at ARC'S' Butcher Boy Mine near Wadsworth, NR. Although biosolids have been used in mine land reclamation in the eastern United States for 20 years, before this pilot study, none had been used on public lands in the arid Great Basin. Land application of biosolids improves soil conditions by improving nutrient uptake, increasing water retention, permitting easier root penetration and enhancing soil fertility. Biosolids increase ecosystem productivity and can lead to significant improvements in the structure and diversity of plant and animal communities. Thus, land application of biosolids promotes biodiversity.

Jan 1, 1993

By E. B. McNew, J. M. Barnes, A. E. Torma

The applicability of biosorbent materials for the removal of uranium and other heavy metals from synthetic and actual uranium mil 1 tailing (UMT) solutions has been investigated. The biosorbent materials used in this study were barium loaded beads of alginate, alginate-dextran sulfate, alginate-carrageenan, and alginate-xanthan gum. These studies were performed in stirred vessels and packed columns. It was observed that 100 percent of the uranium could be removed from a synthetic solution following 2 hours of contact time in a stirred vessel, and 80-100% of U, V, Mo, Mn, Sr, and Zn could be removed from a UMT effluent solution with a packed column. Kinetic evaluations were performed, using a generalized rate equation, on the biosorption of uranium with these barium loaded beads.

Jan 1, 1992

By Barbara Maren Winkler

For mine production problems in mines with varying qualities, both open pit and underground, the linear programming method (LP) has been used successfully. By this method it is possible to keep the total production blend for each period within a required range of qualities while optimizing objectives like production costs, net return, ore grades, other qualities, or a combination of these. Technical restrictions like constrained capacities can be added to the model. This makes LP a flexible and powerful tool for mine production planning. Practical experiences have shown the major influence fix costs have on the actual economic result of a planning decision. It can be proven that fix costs cannot be included in LP models. We describe a way to address this fix cost problem by using mixed integer linear programming (MILP) as an extension to LP in the optimization of a mine planning problem. This raises the issue of complexity. We discuss the computational complexity of the resulting models and the enhancement of model flexibility for the user of a planning system. We demonstrate the method embedded in a practicable everyday planning system for a complex underground coal mine. By computational examples we show how the method improves the economical results of the planning.

Jan 1, 1996

By J. A. Herbst, A. E. Oblad, Y. C. Lo

The major cost in comminution is energy consumption, which can be as high as 50% of the operating cost. Improvements in plant operations have resulted in up to a 15% reduction in energy usage (kw-hr/t). These improvements have been made through the optimization of grinding efficiency and the use of expert model-based control systems. Optimization involves the determination of the levels of the critical-operating conditions that result in the most efficient breakage of ore in the mill. These optimal levels are identified through plant/laboratory test work and through computer simulation using advanced process models. Model-based expert control achieves the maximum performance from the grinding circuit by identifying the characteristics of the ore in the mill with an optimal on-line estimator. Using this information, the control system dynamically determines the operating point that will yield the optimal performance. Two industrial applications of grinding-circuit optimization and model-based control are presented to demonstrate the power of this new technology.

Jan 1, 1997

By Georgios Kafantaris, Carsten Bonde, Nataša Katic

Within the investigation works for the Copenhagen Cityring metro, Geo/CMT have carried out 90 geotechnical boreholes. Together with the previously available investigation, this resulted in more than 15 km of vertical drillings and several thousands of laboratory tests. The design is made for 17 stations, four shafts and two parallel 16 km long tunnels. The geotechnical investigation and design have been carried out in several stages comprising appropriate refinement of structural design and design of excavation operations, including TBM break-in and launching operations at each station shaft. Acceptance of the solution and / or refinement of the investigation and design schedule in the next stage were based on the geological conditions, area availability at surface level, planning and cost-control criteria. The applied recursive design refinement is presented herein with an example of the Østersøgade shaft location.

Jan 1, 2016

By K. Ohga, V. J. Hucka

The presence of methane gas in mines creates hazards of explosions, fire and suffocation. Under certain conditions the occurrence of methane also poses a danger of gas and coal outbursts. Consequently, prevention of gas and coal outbursts in coal mines requires a sound knowledge of methane gas occurrence in mine workings. However, the direct method of determining methane content of coals developed by the U.S. Bureau of Mines is time and labor consuming for measurement, a new transportable methane tester was developed for Japanese coal mines. The instrument automatically measures emission gas from coal samples in the underground and also records and stores the data. Back on the surface, the tester can be connected via a RS 232 port to a PC computer for methane content estimation. Details of this technique are described here. Results on methane content determined in Japanese and U.S. western coal seams are discussed, as well.

Jan 1, 1991

By Gordon D. House, J. B. P. Sawyer

The Bannockburn gold prospect is a new discovery in Ontario's oldest gold camp at Eldorado, eastern Ontario. Mono Gold Mines Inc. of Vancouver, British Columbia, acquired the property in 1980 and in 1984 discovered a previously unreported gold bearing quartz vein system to the northeast of the old Bannockburn Mine. Extensive diamond drilling carried out since 1985 defined a quartz vein system over 475 m (1 ,500 ft) of strike to a depth of over 105 m (350 ft). Limited underground exploration by decline to the 22.9 m (75 ft) level in 1988 confirmed the continuity and tenor of the quartz veins. Gold occurs as native metal with minor sulphides and bismuth tellurides in a quartz carbonate vein system within metasedimentary and metavolcanic rocks of the Grenville Province. Metallurgical test work on a surface bulk sample was favourable. Estimates of drill indicated reserves have been made as well as reserves based on the limited underground exploration.

Jan 1, 1989

By Mark A. White

Surface mining of multiple seams by mountaintop removal and contour mining is complex in Appalachia. Arch of West Virginia, a division of Apogee Coal, has made its operations state-of-the-art to cope with this challenge. Arch of West Virginia moved into the heart of coal mining in Appalachia when Arch Mineral acquired coal reserves and coal operations in the southern West Virginia counties of Logan and Wyoming. These reserves were initially developed at the turn of the century as underground operations. Today, though, they are mined using mountaintop removal and contour mining. The steep slopes in the mountains of Appalachia generated a method of mining referred to as contour mining. During the late 1960s and early 1970s, contour mining was introduced at these operations using front-end loaders with bucket capacities of more than 7 m3 (10 cu yd) that could load 45-t (50-ton) end-dump trucks.

Jan 1, 1995

Mine managers need useful data to support production and maintenance decisions; for example, to evaluate the performance of replacement components. Today, managers rely solely on past experience, supervisors, opinions, and time studies. Our paper describes the concepts and algorithms we are developing for an automatic, intelligent decision support system (IDSS) that will aid managers by reducing and analyzing large amounts of, monitoring system sensor data and report only key production and maintenance information.. IDSS contains a pattern recognition, subsystem (IDSS/PRS) prototype to report graphical trends in traditional time study elements. We are designing. and prototyping a knowledge representation subsystem, using Knowledge Craft Tools, that will learn and adapt to the dynamic mine environment and reason about the recognized patterns using representations of manager's knowledge, equipment, capabilities, and mine layout and operating procedures. This subsystem will reduce, large quantities of time study type information to key issues that interest different managers.

Jan 1, 1989

By G. D. Schena

A decision support system for the management of the mineral resources of a developing country has been derived. The system allows the evaluation of the impact of a mineral project in a developing country in the broad context of its economy. The analysis permits the assessment of the overall socio-economic consequences of mineral prospects and allows incorporation in the evaluation of issues that are broader in scope than the pure financial objectives. The system is built around the Leontief framework of economic analysis. The original input-output model, enhanced to incorporate country-specific behaviour is integrated with cost-benefit analysis and shadow pricing. The analysis leads to synthetic measures of profitability at market and shadow prices. These measures are useful to direct the mineral policy of a developing country through the exploitation of those mineral resources which are most likely to bring about economic growth and social advancement.

Jan 1, 1992

By D. C. Durgin

Located near Ely, Nevada, the Robinson Mining District has produced gold since 1868 from the Ruth? porphyry copper system. Gold occurs in at least seven different deposit types, including porphyry copper ore, silica-pyrite replacements along favorable horizons, fault controlled silica bodies, intrusive breccias, stockworks in bornfels and in retrograde skarns. In all of these the primary controls localizing gold ore are structural .preparation and permeable hosts. Indicator elements associated with gold are Ag, As, Te, and to a lesser extent Sb and Tl. Pb, Zn and F are peripheral to gold or with it depending upon position within the system. The district has produced 87,000 kg (2.8 million ounces) of gold thus far. An additional 19,300 kg (620,000 ounces) of reserves are established, and well over 31,100 kg (1,000,000 ounces) of reserves are anticipated. I

Jan 1, 1989

By C. J. Bise

Safety training requirements differ from mine to mine due to changes in the demographic characteristics of the workers or changes in job and organizational characteristics. Accordingly, a microcomputer-based procedure has been developed to assist mine trainers is determining if undesired worksite performances result from lack of knowledge or skill, which are trainable categories, or from categories that are considered to be non-trainable (such as equipment limitations or management procedures). A special effort was made to understand the psychology of worker behavior by analyzing worker reactions to various organizational and job characteristics.

Jan 1, 1995

By G. Reed Marchant

The control systems engineer is often faced with the problem of designing tests or experiments where the cost of obtaining information is expensive. This is true in aerospace as well as in process industries. In these situations the details of test design should be carefully evaluated before any test is executed so that the maximum amount of information is obtained for the effort expended. In recent years there has been a steady trend towards increased automation, In the process industries this has resulted in extensive review of process variables and, instrumentation techniques, development of more accurate system mathematical models, and extensive investments in complex control system as well as completely automated plants. When planning and developing these systems, where each measure of a process variable is usually expensive, it behooves the design engineer to give considerable thought to the details of test design before instrumentation is procured and installed so that the maximum amount of information can be obtained for the expense incurred.

Jan 1, 1968

By Klimpel. R. R.

Acknowledgments I am honored to be named as a recipient of the Antoine M. Gaudin Award, and I would like to briefly single out four groups who deserve a special thank-you relative to this award. The first group consists of Professor Kawatra, the many international support references that he gathered and the Gaudin Committee itself. I know such things don't come without considerable effort by many individuals, and I'm grateful for their support. The second group consists of the management of The Dow Chemical Company, the managements of various mining companies and, in recent years, the management of G. S. Technologies, all of whom supported me, financially and otherwise, in my grinding, flotation and other particle-processing work. Operations people are the most overworked and under recognized people in the world, whether they be in the mining or chemical industry. Obviously, without extensive industrial support, especially from operating personnel in the mining industry, almost nothing about the work contained in this lecture would have, or could have, happened. The third group consists of a number of coworkers who have played key roles in specifically implementing the new flotation-product portion of this lecture. Of these, Bob Hansen, Don Leonard, Basil Fee, Simon Isherwood, Fernando Cones and Marty Meulendyke deserve special recognition. They have not only been dedicated, but they have been great to work with. Also in this third group are many members of the international academic community, especially those at Penn State. Professor Leonard Austin must be singled out because he took me as a young mathematically oriented chemist and taught me to be an effective process-oriented engineer. Without this experience, I would not have had the over 30-year career as an engineer, which I have loved. In addition, Len planted the size-reduction-research virus in my blood, which I can't seem to get rid of. I also need to mention Professor Frank Aplan, whose obvious love of mineral processing and froth flotation helped to create my interest in flotation. Thus, for those of you who don't like my approach to flotation, it's all Frank's fault. The fourth, and certainly not the least, group to thank is my wife, Charlene, and our two sons, Richard and Steven. No one could have a more supportive family. In every sense of the word, my wife has been my partner from the beginningwe were married at the end of my freshman year in college. She has sacrificed much for me, and I will never really be able to express the depth of my gratitude for Charlene's encouragement, loyalty and support over the past 36 years. General comments on froth flotation The industrial process of froth flotation: Where is it going? I'm here to tell you loud and clear that froth flotation is alive, well, and growing. The inherent characteristics of high mineral throughput per unit of capital, low operating cost per unit of feed, high mineral specificity and high operating flexibility have guaranteed froth flotation an important past and a growing future. As with any evolving technology, there are always trends at the industrial level that are primarily driven by economics. The current trends include: •the movement towards larger and larger equipment, •more alternative equipment designs (e.g., the column cell),

Jan 1, 1996

By S. K. Kawatra

Three International Symposiums-the 14th International Minerals Processing Congress, the 17th APCOM, and the SME-AIME Fall Meeting special symposium on Design and Installation of Com¬minution Circuits-held in 1982 contained a number of papers relating to the fundamentals of processing coals and metallic minerals. In addition, many papers were published elsewhere in the literature. Some of the more significant papers are discussed below. Flavel reviewed key performance parameters, such as energy-size relationships for crushing processes and presented a fundamental basis for optimizing crusher productivity and possibly for development of improved crushers. Pascoe et al. reviewed the use of such control schemes. Magerowski and Karra presented a paper on a computer program developed to and in the design of crushing circuits. The problems associated with the scale-up to very large ball mills were discussed by Arbiter and Harris, and by Kavetsky and Whiten. Both groups concluded that limits on mill productivity arise due to problems associated with particle breakage and transport through mills. Austin et al., and Herbst and Rajamini reviewed the state of the art for the use of grinding circuit simulators for design and control. The effects of mill operating and design parameters on selection and breakage were discussed in detail. The philosophy of control and instrumentation for grinding circuits was extensively discussed by Kawatra and Seitz. Their paper presented for the first time an analytical basis for the inferential particle sizing technique and provided a fundamental basis for the implementation of this technique. The effect of reagent addition variation's on the performance of coal flotation circuits was reported by Kawatra and Waters, and on sulfide flotation circuits by Klimpel et al. Both groups analyzed circuit behavior from a kinetic point of view and reached similar conclusions on the effects of collectors and frothers. The computer simulation of an iron ore flotation circuit also was reported by Kawatra et al. In this work particular attention was paid to the phenomena of froth overloading. Klimpel et al., Kawatra and Waters, and Niemi et al. discussed the philosophy of control by flotation circuits from a fundamental kinetic point of view. An extension of the use of high intensity magnetic separators to the beneficiation of specular hematite was discussed by Thayer and Linkson.

Jan 5, 1983

By R. C. Oberth, C. F. Lee, E. M. Taylor

INTRODUCTION Underground siting of nuclear power stations is drawing increasing attention in various parts of the world. Scandinavian countries took the early lead in this field because of their experience in the design and construction of underground hydroelectric stations and industrial plants, and because they have near-surface rock formations which are ideally suited for hosting large underground caverns. The world's first underground nuclear facilities were built in Norway (Halden) and Sweden (Agesta) and were commissioned in 1959 and 1963 respectively. Figure 1 summarizes the main features of these and two other small-scale European facilities. (1-4) American utilities and regulators are also for a variety of reasons assessing the benefits and penalties of underground siting. A recent study by Sandia Laboratories (contracted by the Nuclear Regulatory Commission (NRC) focussed on identifying potential safety benefits of underground siting. (5) Although the study concluded that underground plants would have improved containment for some accidents, as well as better external protection, NRC, in assessing the overall benefits and penalties, decided not to impose mandatory underground siting for nuclear stations. In June 1976, the California Legislature enacted a law which directed the California Energy Commission (CEC) to examine the issues concerned with underground siting of

Jan 1, 1979

By John S. Livermore

I feel very privileged to be added to the distinguished group that has received this award since the first recipient, Reno Sales, received it in 1954. If my research is correct, the last geologist to be honored was Bill Callahan in 1982. Perhaps the Awards Committee decided it was about time to select a geologist, and I became the beneficiary. Regarding the discovery of the Carlin ore body, it was the culmination of several studies - one going back as far as 1939 when a US Bureau of Mines engineer named W.O. Vanderberg recognized an unusual type of gold mineralization in sediments in northern Nevada. What was unusual was the fact that the gold was so fine that it would not concentrate in a pan. This, plus the study of the Roberts Mountain thrust by Ralph Roberts (1960) and conversations with Harry Bishop, manager of the Gold Acres Mine, pointed Alan Coope and me in the direction of the Lynn Window and, eventually, the Carlin discovery. There has been a great deal written about this discovery. I thought it would be interesting to discuss the evolution of Carlin gold exploration in Nevada since this time and to discuss the changes in perception of this unique type of mineralization. The method used by Coope and me in following up on Roberts' work was to map geologically the Roberts Mountain thrust and conduct geochemical sampling of favorable outcrops and float. Coope was highly experienced in geochemical exploration, as he had graduated from the Royal School of Mines in London, studying under John S. Webb, one of the pioneers of geochemistry as applied to mineral exploration. We first considered using pathfinder elements, but finally concentrated on gold analyses alone, even though the sensitivity of fire assays used at that time was only about one-half part per million. According to the spatial relationship of the mineralization to the Roberts Mountain thrust, as pointed out by Roberts (1960), we were looking for mineralization within the thrust itself. Our models were the known Gold Acres and Getchell mines, which contained reserves on the order of 0.9 to 1.8 mt (1 to 2 million st). These were not of substantial size, but I had hoped we might find more than one of these tributary to a mill that would justify an operation for our employer, Newmont Mining Corp. What we ended up with was the type of deposit we were looking for - an open pit deposit of micron gold, which the old timers had missed because the gold was not capable of being panned. But never in our wildest dreams did we think there was a chance of finding a body containing 10 mt (11 million st) of ore at 0.30 oz/st (10.3 g/t).The deposit was not in the thrust proper but was found in a favorable horizon of Roberts Mountain siltstone that was below the thrust. This is the first example of how a model should not be followed blindly. Newmont was successful in keeping this discovery quiet for some time. After a considerable amount of drilling, a rumor circulated that they had discovered a large low-grade ore body of around 1.7 to 2.1 g/t (0.05 to 0.06 oz/st), which of course would not have been economic with gold at $1.13/g ($35/oz), which was the fixed price at that time. The company, for obvious reasons, did not discourage the rumor. When, however, the true results came out there was a lot of feverish activity. Because of this new type of so-called "invisible gold," which could have been missed by the old timers, the thought was that other deposits would be discovered very soon. The Carlin and other smaller deposits, including Bootstrap, Blue Star and Gold Quarry, were in windows where the lower plate of the Roberts Mountain formation (below the thrust) had been exposed by erosion. This then became the new

Jan 1, 1997