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By D. M. Thayer

In the last decade public awareness of the need for pollution abatement has increased greatly. The concern that had been previously shared by local and state conservation groups has spread to create a national concern for preservation of our non-polluted environmental assets and regeneration of those that have been wasted. Because other current matters such as inflation, civil rights,' tax reform and the Vietnam situation have been the object of most national concern, an extremely strong national pressure base has not been brought to bear on the pollution control crisis. Yes, the word is crisis, for in many areas pollution is of critical concern. One has only to look at Lake Erie, the skies about our major urban areas and many of our major rivers and streams to see this crisis These are not situations that can be corrected overnight. We are faced with two basic problems that should be attacked simultaneously: (1) Cleaning up the present sources of pollution and (2) preventing the generation of new pollution sources. What approach should be taken? As in any engineering problem, the limits must be well defined before a final solution is attempted. Pollution must be defined on a national basis. This means that basic Federal legislation and control is necessary. This should reduce any competitive advantage that can presently be gained by movement of operations from one state or geographical area to another on the basis of differences in local legislation .and enforcement. By giving real numbers as guidelines, selective enforcement can be avoided. As a starting point, for a definition of pollution let us use the following - "Any change in the environment occurring from other than natural causes." This definition may not be satisfactory to all but surely we must be somewhat dramatic in our statements to counteract the present prevailing philosophy. Our statement of this philosophy - "At what level of pollution can we afford to operate?" On the basis of our general definition we would like to state what we feel should be the philosophical statement - "How little can we change our physical environment as a result of operations?"

Jan 1, 1970

By J. L. Young

The McLaughlin Mill started operating in January, 1985. For the first eighteen (18) months start-up, initial operation, and circuit debottlenecking have been done. The mill was designed to recover gold from a refractory ore requiring acid autoclaving pretreatment. This paper discusses the problem associated with bringing this complex hydro-metallurgical plant to consistently achieve design tonnages. Also, briefly described are the mill flowsheet, training program, permitting, and process and project development.

Jan 1, 1987

By M. P. Meehan

The purpose of this paper is to present the key elements in a system; study of the electrical system for a timing and/or tilling operation. The ability of an electrical system to function in a reliable fashion at its proper levels is essential for an operation to be successful. A system study consists of a load study for determining the capability of the electrical network to provide power to the various loads and a short circuit study for determining the capability of the electrical protective equipment to properly protect against fault conditions. The sequence of events in a system study is data acquisition, determining the electrical parameters and analyzing the ability of the system to meet these requirements. If the system is small, herd calculations will be the manner in which the study will be conducted; if it is large then commuters will be used. A load study has as its objectives the determination of the capability and reliability of the source of power, transformers and conductors to satisfactorily deliver power to the loads at an acceptable voltage level. The Information required is a single line diagram showing the source, transformers, conductors and loads.

Jan 1, 1980

By Donald W. Trepp

Colony Development Operation is a joint venture currently consisting of four active members; The Oil Shale Corporation (TOSCO); Ashland Oil Inc.; Shell Oil Company and Atlantic Richfield Company, operator of the project. The initial efforts on the Colony project began in the spring of 1965. Pilot mining and semi-works engineering programs continued, in phases, to completion in the fall of 1972 when commercialization of oil shale was deemed realistic. Since that time, Colony efforts have been directed toward evaluation of the data collected during the semi-works operation and in designing a commercial operation. In October of 1974, Colony announced: "because of economic and national energy policy uncertainties it was suspending plans to start construction of a commercial oil shale plant on private lands in northwestern Colorado, scheduled for spring of 1975."

Jan 1, 1975

By Joe D. Mitzel

The Indian Head fine has been in existence since 1922. For over 56 years there have been North Dakota people mining coal at this same location. The area affected will fit inside a circle 5 km in diameter, and the coal is lignite. The seam thickness has varied from 2.4 m to 3.65m, and the overburden from 6 m to 30 m in depth. me Lignite coal which is being mined at the Indian Head Mine is from 15.8 x l0 6 to 16.7 x 10 6 J per kg; it has a moisture content of 33 to 38%; an ash content of 5 to 10%; and a sulfur content of from 0.5 to 0.7%. The moisture content and the fact that we crush the coal co a top size of 14 cm x 0, are two of the characteristics or the product which cause it to freeze and remain inside of the railroad cars on the slope sheets. The market for the coal initially was almost entirely local coal sales. That is, coal was sold to people in the area who used the lignite to heat their homes, stores, offices, schools, and churches. Back in the early 1920's, there were no stoker-fed boilers, or pulverized fuel boilers, as we have in today?s marketplace. Basically, all of the coal was sold as lump coal, pieces about 30 to 35 cm square, to be used in furnaces: and nut coal with a top size of about 7.5 cm to 10 cm to be used in the old kitchen cookstove. All of the coal fines, less than 5 cm, were screened out and layed onto a pile. There was no market for the smaller sizes of the lignite coal. It has been our experience that when the coal is in lumps or chunks larger than 7.5 cm to 10 cm, there is a very slight possibility of freezing. That is the chunks themselves freeze, but by their nature, they do not cling to one another or form large masses of frozen material which are difficult to remove from the slope sheers of the railroad cars.

Jan 1, 1980

By Jeffrey J. Daniels

Advances in borehole geophysical research for mineral assaying, and remote detection of mineralization away from the borehole. Nuclear activation measurement research has provided accurate in situ assays of economic metals with neutron-gamma activation, using a high resolution intrinsic-germanium detector. Although nuclear activation analysis is the present "best-hope" for obtaining in situ assays for some elements, gamma-gamma and magnetic susceptibility measurements can provide accurate assays for lead-zinc and magnetite, respectively. Borehole optical spectroscopy and x-ray fluorescence are being investigated as possible in situ assaying techniques for some minerals. More laboratory and field calibration research is needed before nonlinear complex resistivity (NLCR) can be routinely used as a quantitative assaying tool. Field tests have shown that variations in the local geologic environment can affect the quantitative accuracy of assay values from downhole NLCR measurements. Deeply penetrating borehole geophysical methods are increasingly being used for mineral exploration as drilling costs and exploration have increased. Borehole electrical measurements have been shown to be useful for detecting conductive orebodies that are not interesected by a drillhole. Hole-to-surface resistivity, and surface-to-hole time-domain electromagnetics are demonstrated to be particularly effective for defining mineralized zones in a massive sulfide environment. Borehole gravity meters and three-component magnetometers have been developed and should prove useful for defining geologic anomalies away from the drillhole.

Jan 1, 1985

By V. B. Achanti

Reliability of the compressive strength of a coal seam determined in the laboratory is often subjected to debate. Effects of the coal seam's inherent characteristics, specimen preparation, testing procedure, testing condition, and a number of tests often result in drastic variation of the strength data. This paper deals with the development of a testing procedure for determination of coal seam compressive strength in the laboratory. Coal samples from two different coal seams were tested. First, the inherent characteristics of each coal seam such as coal structure, Hardgrove Orindability Index (HOI), Slake Durability Index, proximate analysis, and mechanical properties namely Young's modulus and Poisson's ratio were determined to categorize them in terms of their characteristic severity liable to produce variable strength data in typical laboratory tests. Second, two commonly used laboratory specimen shapes namely; cylindrical and cubical, were tested to determine which shape produced the least variation of data and reproducible strength values. Third, four loading rates within the static testing range (Le. 0.007 MPa/s (1.0 psi/sec), 0.07 MPa/s (10 psi/sec), 0.34 MPa/s (50 psi/sec), and 0.7 MPa/s (100 psi/sec)) were used to determine an ideal loading rate. Finally, the number of test samples required to produce strength data within the acceptable standard deviation, considering coal seam characteristics were established.

Jan 1, 1996

By M. K. Buder

Over the years, electric utilities have been faced with declining steam-coal quality, rising coal prices, and increasingly rigid and costly environmental standards. As a result, many utilities are beginning to show an interest in coal cleaning to upgrade coal by improving its heating value and reducing its sulfur content. Among the primary questions that must be answered for these electric utilities is whether the cost of coal cleaning can be offset by the potential cost savings in coal transportation and utilization in power generation. In search of at least a preliminary answer to this question, the Electric Power Research Institute (EPRI) engaged Bechtel to perform a case-by-case economic study to examine the cost effects of using cleaned versus raw coal to fuel new electric power plants. The results of two of the seven cases studied which involved western coals - one from Montana and another from Utah - are reported in this paper. Coal cleaning appeared to be a cost effective option for the Utah coal, but only marginally economical for the Montana coal. These cost results are expected to change to favor coal cleaning to a greater extent with the application of the final revised New Source Performance Standards regulating SO2 emissions just issued by the EPA. The study was based on the regulation originally proposed by the EPA under the 1977 Clean Air Act Amendments.

Jan 1, 1979

By G. Van Weert

Oxygen transfer from dispersed air in agitated slurries represents an important unit operation in the minerals processing industry. Gold leaching, iron precipitation and especially bio-oxidation come readily to mind. However, little engineering information is available on the variations between impeller types on such O2 transfer. Engineering literature on the subject, i.e. information which relates slurry density and energy input to O2 transfer, is reviewed and compared to current experimental work. The latter was carried out with minus 50 micron sand/water slurries in a 64 I laboratory tank of standard proportions, equipped with a variable speed drive with torque meter. A standard Rushton turbine and a specifically sized A315 were compared. Results confirm an increasing impairment of O2 transfer with increasing slurry density for both impellers. The volumetric mass transfer coefficient, k,a, in a 10 vol. % slurry shows a decrease of 30% compared to the k,a in water. At 20 vol. % sand this decrease is near 50 %, depending somewhat on superficial gas velocities. Power efficiency, i.e. the kg O2/kWh, decreases about 25 % more rapidly for the Rushton turbine than for the A315 with the addition of sand. However, for equivalent O2 transfer the Rushton turbine was more efficient in this work. Experimental results are presented and their significance for slurry bio-oxidation discussed.

Jan 1, 1996

Jurist, educator and historian Neil Reynolds will be the keynote speaker at the National Mining Hall of Fame's 11th annual induction banquet on Sunday, Oct. 11,1998 at the Pointe Hilton Resort in Phoenix, AZ. Reynolds is Municipal Court Judge for the City of Leadville, CO, home of the National Mining Hall of Fame & Museum, and a fifth-generation resident of the community. His family staked mining claims on nearby Mount Massive in 1862. Judge Reynolds is a fulltime faculty member at Colorado Mountain College, Chairman of the Lake County Historic Preservation Advisory Board and practices law in Leadville. In announcing the speaker, Board Chairman Richard Moolick said seven inductees into the National Mining Hall of Fame will join 138 mining greats previously honored in the annual ceremonies. This year's inductees will be enshrined by Thomas Falkie, president and chief executive officer of Berwind Natural Resources of Philadelphia, PA. Moolick also announced that Jeffrey Clevenger will be the master of ceremonies for the induction banquet. Clevenger is executive vice president of Cyprus Amax Minerals, Englewood, CO and president of Cyprus Climax Metals, Tempe, AZ. A cocktail reception at 6:30 p.m. will precede the black-tie (optional) dinner, to begin at 7:30 p.m. For additional information, contact Esther Mellott at 719 486 1229. Here are the biographies, then, of this year's seven inductees to the National Mining Hall of Fame & Museum.

Jan 1, 1998

By K. H. Nimerick

Froth flotation of coal is growing in importance and complexity. Some of the reasons for these changes follow. 1) A need exists for energy resource conservation. 2) Preparation plants are processing widely varying coal -- deep seam, strip and stockpiled either separately or as blends. 3) More fines are being generated because more mines are using automatic mining equipment. 4) It is more practical and economical to remove ash and sulfur at the preparation plant than during utilization.

Jan 1, 1982

By Nicholas C. Lias

Quartz crystals are the raw material from which are made the crystal units utilized in filters and oscillators so vital to the performance of all long distance communications systems. These devices act as the heart of equipment that permits a single telephone cable to carry hundreds of conversations simultaneously. Quartz crystals are of value in communications because of this piezoelectric nature, that is when an electric signal is applied to the quartz, there is a resulting mechanical motion and conversely, a mechanical stress results in an electrical output signal. A plate cut from a quartz crystal will oscillate at some specific frequency, which is determined by the physical dimension of the plate. During the early stages of telephony, all quartz plates were cut from natural quartz, which was imported mainly from Brazil. Since the source of this important raw material was based upon a foreign supply which is located at a great distance from the user and could be vulnerable in time of a national emergent, it became necessary to maintain a large inventory of this strategic material. Also due to the considerable cost of natural crystals of a size and quality suitable for Bell System use, an investigation was made by Bell Laboratories into the possibility of developing a substitute material. The effort was successful and led to a joint development program between Bell Laboratories and Western Electric. This program brought about the design of manufacturing facilities capable of producing large quantities of cultured quartz at Western's Merrimack Valley Works, No. Andover, Massachusetts.

Jan 1, 1973

By David A. Milligan, William Cobb

2.1 INTRODUCTION This chapter provides the reader with a sense of how a heap leach project may make an orderly, and hopefully non-traumatic, transition from discovery or acquisition to project construction. In making this transition a project can pass through several project development phases (i.e. ore definition and delineation, conceptual engineering, detailed engineering, and ultimately on to project construction and operation). "Go" or "no go" decisions may occur at any point in each of these phases. The transition from ore definition to detailed engineering should be accomplished via a well thought out program of interdisciplinary studies and an integrated, interdisciplinary project team. This chapter also describes, in general terms, a "roadmap" approach to the project evaluation process that must occur as project planning and development progress. It is the experience of the authors, as well as a myriad of companies who have been through the heap leach project development process, that a systematic approach will save many headaches, and many dollars. In fact, it is safe to say that a project with no formalized system of "objectives setting" and "milestone charting" may well flounder along the way, even if an economic ore body exists. Many papers and technical articles have been written about various aspects of mineral resource appraisal, economic evaluation, and mine development. Most of these invoke the same general philosophy of a systematic approach to project evaluation and development, although methods cited for attaining goals are quite variable. This is undoubtedly appropriate, given the fact that there is great variation in approach to project development (e.g., climatic considerations, ore body size and physical ore characteristics, permitting constraints, etc.). For the purposes of this chapter, two primary sources of information have been used to highlight the "road map" approach previously alluded to. These sources are cited throughout the text as Mackenzie (1980) and Snow and Michel s (1986). A brief summary of each of these sources is provided below: Brian GJ. Mackenzie of Queens University (Mackenzie, 1980) has developed a wealth of information concerning project development topics. Much of this information is synthesized in his notes for a short course entitled : "Mineral Exploration Planning and Economic

Jan 1, 1988

By S. Bhamidipati

Abstract. Controlled flow is an aspect often desired in mine ventilation. This is normally obtained by using fans and regulators to achieve the required pressure balance in the system. Preference for a certain network layout of these control devices is influenced by technical as well as legal and economic factors. In this study, a model is developed based on an economic criterion by which an optimum layout of fans and regulators for a controlled flow system can be determined. The concept is analo¬gous to the critical path crashing. However, a linear programming package is used to demonstrate the solution procedure for a hypothetical venti¬lation network.

Jan 1, 1983

By Matthias Neuenschwander, Andreas Theiler, Patrick Steinle, John Singer, Martin Vogel, Diego Martini, Ömer Ündül, Markus Weh

"Quartz Dust is a major health hazard in underground works, wherever the ground contains quartz and depending on the chosen method of excavation. A research project initiated by the Swiss Tunnelling Society and realized by the Swiss Federal Institut of Technology, Zurich, established a correlation between the potential of quartz dust generation during excavation and well known geotechnical characteristics – the Cerchar Abrasivity Index CAI and the Uniaxial Compressive Strength UCS - of ten typical Swiss rocks. The results are at the center of a new guideline by the Swiss Society of Engineers and Architects on the requirements for early project stages regarding ventilation and logistics in function of the quartz dust related risk of the expected ground type of the project. The approach presented could be applied worldwide, contributing to more effective health protection as well as to better cost stability in underground works. CONTEXT Respirable quartz dust (aerodynamic diameter of particles < 10 micron) is universally recognized as a major workplace health hazard. Chronic bronchitis, silicosis and lung cancer can be caused by excessive exposure to quartz dust, as has been proved by many medical studies. Therefore, the legislations of many nations specify a maximum workplace concentration (Maximale Arbeitsplatzkonzentration MAK, Occupational Exposure Level OEL). In Switzerland, for example, the Threshold Limit Value TLV for respirable Quartz or Crystalline Silica imposed by the Federal Committee on Exposure Levels (Grenzwertkommission) is 0.15mg/m3 air. Some nations refrain from establishing a OEL because of the carcinogenic nature of quartz."

Jan 1, 2016

By Milan Lipensky

This paper discusses the longwalling practices used at the San. Francisco Mine of Compania Minera Autlan in Mexico, in. the mining of a sedimentary, manganese deposit. Bethlehem. Steel Company is a part owner of this property. The San. Francisco Mine is located approximately 580 miles west of Mexico City, on the outskirts of the town of Autlan, in the State of Jalisco. The ore is shipped from the port of Manzanillo 120 miles southwest of Autlan. The mining method is a variation of the longwall retreat system, using friction. props that, until recently, had been used only in coal mining operations of Europe and the United States. However, due to the structure of the ore body and the modified longwall system that is practiced, there exists some unusual variations, such as: .1) friction props set by a mechanical two-step lifting device, 2) drilling and blasting, against the friction props, 3) a highly fractured and undulating, volcanic tuff roof; 4) displacement faults-up to 5 meters, and 5) a relatively stable, irregular floor.

Jan 1, 1964

By Immo H. Redeker

This is a final progress report on a cooperative project conducted by three private feldspar companies,** North Carolina State University, and the federal Bureau of Mines. The object of the project was to reduce the feldspar tailings disposal problems at the flotation plants in the Spruce Pine area of North Carolina. The initial phase of the project revealed that high tonnages of saleable feldspar and quartz were lost in the tailings and the three feldspar companies are now concentrating their efforts on feldspar recovery, either by reclamation from the tailings as suggested by the Asheville Minerals Research Laboratory or by improvements in metallurgy in the existing plants.

Jan 1, 1970

By L. E. Murr

Solution flow in leach dumps and heaps or in columns of representative rock has been the subject of only limited studies. This is a regime involving unsaturated flow in semiconsolidated rock with a wide size distribution. Even the concepts of continuous flow systems are fairly recent, and have evolved from the search for better methods of operating industrial chemical reactors. (1-3) Waste rock consolidation and permeability play a key role in solution flow characteristics. Harris (4) suggested that bulk density variations in a leach dump could alter the particle-to-particle contact, and that large particle aggregates could act like single, large particles . In the limiting case where the bulk density approaches that of the undisturbed, consolidated rock, the entire waste unit would behave as a single particle. Roman (5) treated the phenomenon of bulk density and its effect on consolidation in terms of lixiviant flow paths or solution channeling in leach dumps. Like Harris, he assumed that no solution moved through particles or particle aggregates associated with zones of high bulk density. Solution flow paths are thus effectively separated by particle regimes, creating solution channels in the waste body. While some attempts have been made to describe solution flow in leach dumps and related systems by utilizing computer model approaches and laboratory- scale simulations (5,6), there have been no direct, large-scale observations of solution movement in channels or of the actual channel sizes and distributions within a waste body. This paper describes a series of experiments involving large-scale, controlled waste leaching tests, conducted over a period of several years, and aimed at providing some direct observation of the changes in waste consolidation and permeability, the size and distribution of solution channels, the movement of such channels with continued solution application, and other features relating to solution flow during the leaching of low-grade waste. These results are then combined with mineralogical information to explain observed leach behavior.

Jan 1, 1981

By Robert E. Barrett

The history of mine safety legislation in this country is also a history of mine explosions. Nearly every piece of safety legislation that has been introduced or amended has resulted from some type of a disaster. When coal was first discovered and mined, it was extracted from along outcrops. As the coal became depleted near the surface, underground mining developed. When the first mine penetrated the outcrop, a great number of problems developed, many of which remain with us today. One of those problems is the potential for mine ignitions and explosions. Naturally, when underground mining progressed a few feet into the outcrop, some type of artificial light was needed. Early accounts of mining in Spain, Italy, Japan, and Great Britain indicate that torches served to light the mines. Later, candles were used, and still later, earthern oil lamps containing fish oil were used. As workings got deeper, explosions began to occur. When one did occur it was thought to be the work of goblins or the devil. As explosions became more frequent, it became very obvious that the use of open flames for lighting was very dangerous. A substitute was sought. Dried fish skins which gave off a weak phosphorescent light were tried. A mixture of flour and lime made from oyster shells called Canton phosphorous was also tried unsuccessfully. Fireflies in a bottle were also used.

Jan 1, 1976

By Edward L. Vickers

When I was originally asked to give this talk, I had certain preconceived ideas of the mining industry&apos;s reaction to Operations Research. It seemed at the time to be a rather simple task to collect these ideas for presentation here today. Jotting down these notions, I became concerned that overexposure to this activity called OR perhaps had clouded my outlook on what was actually being done on a nation-wide scale. I felt, to have a better cross section, a questionnaire of current industrial activity was in order. I solicited the response of some 75 mining companies varying in sizes and operating characteristics, and I am pleased to report that the response was good. I received answers from 51. The questionnaire was intended to measure the degree to which their concerns were actually engaged in OR efforts. With all due respect to the people who were so gracious as to answer the questionnaire, I feel that there is a tremendous misconception as to the designed purpose of OR. This is not to imply that there are no active OR groups in the mining industry. But by in large, the majority of the companies sampled appear to be somewhat confused as to what OR really is.

Jan 1, 1962