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By Ben L. Seegmiller

INTRODUCTION Site characterization using oriented borehole core is the subject of this paper. Borehole core is a standard source of data for rock mechanics investigations. Oriented borehole core provides data whereby the geometric orientation of various geologic discontinuities (faults, joints, bedding, etc.) may be determined. The orientation and strength characteristics of discontinuities are important in many engineering investigations and in particular, in slope stability analyses. In heavily vegetated or soil covered situations, oriented borehole core may provide the only means of assessing the subsurface planes of weakness which characterize the site. The purpose of this paper is to briefly describe various methods or orienting core, core characteristics which may be logged and the methods of processing and using the data for site characterization.

Jan 1, 1977

By Barada K. Mishra

The potential merit of the discrete element method (DEM) as a numerical tool for analyzing process engineering problems involving particulate material is discussed. In this method, the dynamic equilibrium equations for each distinct and deformable body are solved. Therefore, it readily lends itself to modeling large numbers of discrete, interacting bodies as in mineral processing operations where a charge of particulate material is processed. Here some applications of DEM are reported: motion of particles in the ball mill, mixer, and jig. Although DEM has made very little headway in mineral processing research, it is shown here that a host of other areas of industrial interest in the context of flow of particulate materials can also be made amenable to analysis by this method.

Jan 1, 1993

By C. J. Bise

Continuous mining accounts for about 69% of the nation's underground coal production. This level is not expected to change much in the near future. This is because continuous mining represents the primary means of under- ground coal production. It is also the primary means of driving development entries for underground coal mines, including longwall mines. The continuous miner worksite contains many characteristics that can lead to personnel accidents. It continues to be an area of concern for mine managers, safety engineers, and training coordinators. In an effort to assist mine management in attempts to reduce the number of accidents and injuries sustained in this area, this paper presents a loss-control-based, non-intrusive strategy for conducting safety evaluations at continuous miner worksites.

Jan 1, 1991

By B. J. Schat, A. W. O. Bots, O. S. Langhorst

Amsterdam City Council is building a new metro line, the North–South Line. The line passes under Amsterdam Central Station (a listed building) about 18m below street level. The retaining wall that has to be built underneath the existing building is an innovative construction consisting of two rows of steel piles interspersed with a solid mass of overlapping jet grout columns: a composite ‘sandwich’ wall. This paper gives an overview of the approach taken to designing (computational models) and building the retaining wall. Special attention is paid to the observational method used for the construction of the jet grout columns.

Jan 1, 2007

By M. J. Farrell

The threat of global warming and its prominent position in public discussion and political debate requires all industry to take stock of its contribution to rising atmospheric concentration of greenhouse gases. For the primary metals industry, the first step must be to identify the pattern and range of emissions at each step in the production chain. Only then can the industry assess the economic consequences of the penalties on emissions that will be imposed by governments and regulators and devise cost-effective plans to avoid or mitigate such penalties. While some work has been done to estimate carbon dioxide (CO2) emissions using Life Cycle Inventory analysis, this approach is less useful than site-by-site emissions estimates. It is the level of specific emissions at each site that will ultimately deter-mine carbon taxation liabilities and participation in emissions trading schemes. Most mining companies have moved with the times to issue sustainability reports for their operations. But in the absence of any standardized reporting format, it is difficult to make useful comparisons between even the best-reported producers on a like-with-like basis. For this reason, Minecost.com modeled the use of fuels and energy used in mining, milling, shipping and metallurgical treatment to cover ?cradle-to-gate? emissions of greenhouse gases resulting from the production of the major base metals copper, zinc, lead and nickel. Greenhouse gas emissions ? overwhelmingly carbon dioxide ? are associated with the consumption of energy at every step in the production chain, from exploration through mining to the production of refined metal. Producers of primary metal employ diverse technologies to mine, mill, smelt and refine several different types of ore. Every orebody has its own special characteristics. In addition, most base metals are produced in concentrate that must be transported to smelters, with con-sequent emissions consequences.

Jan 1, 2009

By Ellis Brien, O&apos

The fine coal fraction of a coal stream is that fraction which contains particles essentially in the -28 mesh size range. This fraction will normally first appear, in a coal preparation process, as a result of classification to segregate raw coal into various size components for beneficiation. More specifically, it could appear in desliming screen underfiow, classifying cyclone overflow, and in other process circuit components. It's recognized that the top size of this fraction has been determined more by secondary reasons, such as desliming screen area for the heavy medium cyclone circuit, the dewatering equipment for the fine clean coal, or even the stability of the refuse thickener circuit. Benefits, both economic and environmental, gained by beneficiating the fine coal fraction of a raw coal stream are increasing in number, until today, fine coal beneficiation is a necessity in most coal operations requiring any degree of preparation. This is due to some of the following reasons: • In the past it was frequently more economical to discard -28 mesh raw coal sizes than to recover the coal values from them. Today, mining costs have escalated to the point where all coal values leaving the mine should report to the finished product if possible. • Today's mining methods are producing run-of-mine coals containing higher percentages of -28 mesh sizes. This heavily weighs the economic balance in favor of beneficiating this fraction. As much as 25% of the run-of-mine coal from some mines is in the fine coal fraction. Beneficiation is recommended so that clean coal contained in the fraction can be recovered to reduce the loss of coal values. • Existing and pending environmental regulations mandate that solid fuels now consumed in power station boilers contain almost no pyritic sulfur. This form of sulfur appears in raw coal in the fine coal fraction, but can be removed by coal beneficiation. Environmental considerations dictate that every year, more of the fine coal produced for steam generating purposes in the US be beneficiated. To deliberately discard any portion of the fine coal can only add to this cost, not only in the sense that fewer tons will be recovered but, more importantly, additional tonnage will be diverted to the most capital- and labor-intensive section of the entire preparation plant-the fine refuse dewatering section. It is apparent to preparation engineers that dewatering and ultimate disposal of the fine refuse derived from this beneficiation step is certainly the most difficult technical problem presented in the entire plant design. Therefore, any beneficiation procedure which increases the fine coal recovery, or in any manner decreases the tonnage of fine refuse to be dewatered, is going to be cost effective. Since the -28 mesh fraction contains both coal and refuse particles in their finest particle sizes and thus presents the greatest degree of liberation, one would immediately infer that the highest degree of beneficiation would be achieved. This is not the case-the opposite is more likely true. Conventional coal cleaning devices based on specific gravity (such as

Jan 8, 1980

By David Wright, Colin Burns

Successful leaching of gold depends on appropriate chemical conditions; contact between leach solution and the gold particles; separation of the leach solution from the solids and extraction of the valuable ion from the solution. Irrespective of the leaching method employed the chemical conditions required are similar as is the dependence of solu­tion/gold contact on liberation. The various leaching methods available vary in the means by which gold/solution contact and solid/liquid separation are achieved. The essential difference between heap or vat leaching techniques and those involving agitation of a slurry is dependence on percolation for effective gold/solution contact. The most significant factor preventing uniform percolation is the presence of fines or clays. The quantity and character of the fines fraction is ore type dependent and may result from crushing, degradation during stacking or leaching, or the natural size distribution of the ore. The problems associated with fines can be aggravated during stacking and preparation of the heap. Segregation during stacking can result in concentration of fine particles at the centre of heaps. Further concentration of fines may also occur during irrigation by the movement of the fine particles with the solution. The end result is that the areas in which fines are concentrated become areas of low permeability. The contact between leach solution and the ore in such areas is, at best, slowed down dramatically and, in some cases, prevented altogether. The consequences of this phenomena are slow leaching and a reduction in recovery. The conventional solution to this problem is well known. Agglomeration of ore prior to heap leaching is practised widely. The effect of agglomeration is to immobilise the fines by causing them to adhere either to each other or to larger ore particles. The net effect is that the ore behaves as if no fines were present. The use of agglomeration is limited only by its cost, the most significant components of which are the cost of binding agent, commonly cement, and the capital cost of the agglomerating equipment.

Jan 1, 1995

By J. W. Carson

Introduction Many bulk solids such as coal, limestone, and fine moist ores often flow unpredictably out of bins, hoppers, and boreholes. Vast amounts of time and money are spent-with or without success-on flow promoting devices. In addition, many solids segregate in storage, feed erratically, flood, arch, rathole, and stick to bin walls reducing the live capacity. This article discusses bulk solids flow properties and provides guidelines for designing storage bins, hoppers, and feeders to provide reliable flow. Bulk Solids A bulk solid is a granular material consisting of discrete solid particles-submicron to several inches in size-that is handled in bulk form (for example, in a bin or silo). The gas filling the voids is generally insufficient to fluidize the material and the liquid (usually water) content is assumed to be less than saturation. Types of Flow Problems To design an efficient storage system, an engineer must be aware of problems that can arise during storage and flow of bulk solids: • No flow. A stable arch or pipe (rathole) develops within the solid, stopping flow. • Erratic flow. Momentary arches form within the solid, (ratholes), partly or completely empty out, and then collapse. • Flushing. Powders become fluidized, aerate, and flush uncontrollably through the bin outlet. • Lack of design capacity. A large part of the stored material remains stable around a rathole. Manual prodding, severe vibration, and even explosives may be used to restore flow. • Segregation. Smaller particles tend to sift through the voids between larger particles causing accumulations of fines and coarse in various areas of the bin. • Product degradation. Some materials spoil, cake, or oxidize if they remain in a bin too long. This is usually caused by a first-in-last-out flow sequence. • Level control. Measuring the volume of material left in a bin is difficult if a rathole develops. In one portion of the bin the level control device may indicate the bin is full; in another portion it may indicate it is empty. Eliminating Flow Problems All flow problems can be minimized or prevented by suitable design of the bin/feeder unit. This involves knowing the flow properties of the solid, then choosing the appropriate type of bin and feeder to establish the desired flow pattern. There are three types of flow patterns that may occur in a bin: funnel flow, mass flow, and expanded flow. Funnel flow occurs when some of the material in the bin is stationary while the rest is in motion. Funnel flow bins, shown in Fig. 1, are characterized by: • Low head room. A flat bottom or shallow hopper bin has large storage capacity with minimum height. Unfortunately, all this storage capacity may not be usable ("live"). • First-in-last-out flow sequence. The first material put into a funnel flow bin is the last material withdrawn because the flowing material is concentrated in the region directly above the outlet. • Ratholes. Because of the flow channel that forms, a stable rathole develops if the material has sufficient cohesive strength. • Erratic flow. Once a rathole becomes partially or completely empty, it may collapse creating a stable arch and erratic flow. • Flushing. Collapsing ratholes cause flushing and flooding of fine material. • Segregation. If a bulk solid has a tendency to segregate, this tendency will be accentuated as the material is discharged from a funnel flow bin. Funnel flow bins are suitable for coarse, free flowing, nondegrading solids, when segregation is not important. Mass flow occurs when all the material in a bin is in motion whenever any is withdrawn. Char-

Jan 3, 1983

By I. Jashnani, J. R. Lawter, D. B. Lindsay

INTRODUCTION It is a generally recognized obligation of owners and operators of underground mines in the United States to protect the health of miners against the potential carcinogenic effect of airborne alphaemitting radionuclides, in particular the shortlived radioactive daughter-products of 222Rn. In meeting this obligation, a number of strategies are available, and it is largely up to the operator to decide what combination of methods he will use. Because the officially accepted theory of the mechanism by which radon and its short-lived progeny cause cancer of the respiratory system, the objective in controlling this health hazard is to limit as far as possible the inhalation of the three daughter products, 218Po, 214Pb, and 214Bi. (214Po, the fourth nuclide in the chain, is so short-lived that its alpha-decay occurs almost instantaneously after the beta-decay of its parent, 214Bi.) The reasoning in this theory leads to the conclusion that the alphadecay of radon itself causes essentially negligible physiological damage, and that the amount of daughter product activity attributable to decay of radon within the respiratory system is also very small. As every ventilation engineer in this business knows, however, focusing remedial actions exclusively on the daughter products themselves is choosing the hard way, and will probably never lead to effective control of this health hazard in underground mining activities. The reason for this troublesome fact can be seen in Figure 1. Let us say that we have air containing 222Rn and its short-lived daughters in near-equilibrium, a not-uncommon condition in the air of a poorly ventilated underground mine, and that we wish to purify it by removing only the toxic daughter products. If we have been very thorough in our purification efforts, we might expect to achieve a 99% reduction of the Working Level (WL) measurement. Figure 2 allows us to examine closely the early regrowth of WL's in this freshly cleaned air. Within the first five minutes, for instance, the WL's are back to 10% of their full equilibrium value, and ten minutes later the level has more than doubled and is on its way to an almost complete defeat of the clean-up effort by the end of the next hour. It is quite clear from this simple illustration that no matter how effective an air-cleaning system may be if it is directed only at the selective removal of the toxic trio, 218Po, 214Pb and 214Bi, its beneficial effect will be quite temporary. A truly effective attack on the problem must always include methods aimed at the control of the unruly parent, radon. Then, even if its progeny have an inalienable "right to life", their brief lives will not be spent in the miners' lungs. The object of the present paper is to show how state-of-the-art environmental air

Jan 1, 1981

By S. Slottee

The technology of making and using ?paste? from mine tailings is increasingly well known by the minerals industry. The primary applications are water recovery and ?stacking? of tailings with minimal use of dams and ponds. This paper highlights some applications, other than water recovery and stacking, that have come to the attention of a paste thickener equipment supplier. As generated by thickeners, paste (also called ?thickened tailings?) is a non-settling, relatively high concentration, suspension of solids that can be pumped. Paste deposits with an angle of repose, allowing minimal use of dams. High solids concentration allows more water recovery at the paste thickener than is achieved in conventional and high rate slurry tailings thickeners. This paper is based on paste as produced in a flow sheet that includes a thickener, underflow pumps that are typically centrifugal, transfer pumps that can be centrifugal or positive displacement, and a distribution system at the deposition site. Examples of paste applications other than water recovery or stacking include: ?mine? an existing tailings pond by removing slurry, recovering coal or iron ore values, and return the new tailings to the pond as a paste that does not res-suspend; use paste to seal an existing tailings pond from leaking to groundwater or to an underground mine; extend the life of an existing tailings pond by thickening the tailings to paste; move an existing dry tailings impoundment to a new location by slurrying, pumping, paste thickening, and redeposit; minimize the size of a filter by paste thickening the feed; operate a paste thickener and filter in parallel on a tailings stream with re-mixing to achieve a high solids concentration. The use of paste tailings technology has been expanding over the last 15 years. The applications, both implemented and under consideration, are increasingly diverse and include all minerals tailings. Tailings handling designers should always consider a paste option to the conventional slurry solution.

Jan 1, 2011

By I. Tsolas

This paper presents the use of non-parametric approach (i.e., data envelopment analysis, DEA) for the development of environmental sustainability indicators in mineral processing using environmental, economic and/or integrated indicators (i.e., indicators that interrelate two dimensions of sustainability). A case study based on real publicly available data is presented to illustrate how the proposed approach can be implemented in practice. The merit of this approach, which is based on the productive efficiency framework, is that it provides environmental sustainability indicators that can be used internally for benchmarking purposes and externally for sustainability reporting.

Jan 1, 2008

By Harold E. Rowen

The listed title of my talk to-day is "MODERN ON STRAND SINTER COOLING". Perhaps it should he ve been "COMPLETION OF SINTERING ON THE STRAND" as the two are synonymous. By the very nature of the DWIGHT-LLOYD SINTERING PROCESS partial cooling on the strand is always present, but not completion of sintering and cooling on the strand. I have mentioned the Dwight-Lloyd process just to be certain the type of sintering under discussion is fully identified because some of the basic mechanisms of sintering occur in various pyro-processing of fines lying in close quiescent contact, such as powdered metals practices, some types of pellet induration, firing of briquets, or other compacts, where the entire bed is brought to, and held at, the high reaction temperatures of sintering. Figure 1, The continuous sintering process as originally conceived consisted of intimately mixing carefully proportioned burdens, placing them in a comparatively thin, draft permeable layer, on a moving grate and igniting the surface while drawing sir through the bedded burden. The moving grate was advanced slowly as the line of burning fuel travelled from the surface to the bottom of the bed and no more fire zone could be seen.

Jan 1, 1973

By R. H. Ring

The Automatic Extraction System (AES) was designed and built under a U.S. Department of Energy Contract by the National Mine Service Company in cooperation with the Lee Engineering Division of Consolidation Coal Company. The Pennsylvania State University, Mining Engineering Section, was contracted as an independent auditor of the AES performance. The AES had a rotating cutter drum like a continuous mining machine; but two hydraulically powered roof supports, four roof-bolting drills, a dust scrubber, a ventilation fan and ducting in the roof supports, semi-automatic control, an extensible chain conveyor, and other innovations led to the distinction "extraction system" as opposed to "miner-bolter" or "continuous mining" machine. After design and assembly, the AES was field tested experimentally in an underground coal mine. The in-mine performance audit was preceded by a computer simulation of the potential production for a later comparison with the actual tonnage mined by the AES. This paper describes the results of an in-mine trial and assesses the production potential of the AES.

Jan 1, 1980

By L. A. Garfield

Since the start of mining operations at White Pine in 1953, over 22 miles of drifts have been driven for the purpose of developing the ore body. The drifts, normally driven in multiples of three or five headings, serve as conveyor belt routes, ventilation ducts, equipment and haulage roads, and initial access to mining blocks. Development openings in the flat-lying, bedded ore body are driven in rectangular section from 16 to 32 feet wide and from 8. 5 to 16 feet high. The floor level normally coincides with the bottom limit of the chalcocite values and the roof or back is carried at the most competent stratum adjacent to the top of the ore. A development front consisting of five headings and associated crosscuts is advanced at an average rate of about 100 feet per month using conventional drill and blast techniques and equipment. The cyclic nature of the functions involved in driving the openings and the need to include them in production schedules preclude significant improvements in advance rates using current drill, blast, muck, and haul sequencing.

Jan 1, 1969

By C. A. Rowland

Introduction Comminution efficiency, as measured by relating circuit performance to the consumption of energy and the time and money required, can be determined by the following comparisons: Theoretical efficiency: The theoretical efficiency is the actual energy consumed in a comminution machine compared to the theoretical energy required to perform the size reduction. Operating efficiency: The operating efficiency compares the operating work index of a comminution machine to the Bond work index of the ore, as determined from bench-scale crushing and grindability tests or pilot-plant tests. Economic efficiency: The economic efficiency is comparing income from production to predicted income. Key words: Comminution, Bond work index, Grinding, Crushing, Ball mills, Rod Mills. Theoretical efficiency In their book Process Engineering of Size Reduction - Ball Milling, Austin, Klimpel and Luckie (1984) stated that, "We have tried throughout this book to avoid the use of the term grinding efficiency because the degree of conversion of energy to useful size reduction is an ill-defined concept. In addition, the only efficiency, which is of real interest, is the meeting of product specifications at the minimum cost." The National Materials Advisory Board, National Re¬search Council (1981), in the abstract of a report titled "Comminution and Energy Consumption" stated that, "Up to 99% of the energy consumed in grinding these ores may be expended in the movement of machinery, with noise and heat the undesirable byproducts, thus leaving only 1% of the energy available for size reduction. Coupled with this is evidence that many of today's crushing and grinding techniques not only are antiquated but have little or no scientific base of understanding." Throughout the past 50-plus years, grinding efficiency has been referred to as being from 1 % to 10%. The measurable basis for these observations is difficult to establish, but they appear to be based on production performance compared to theoretical energy requirements for the work done. The theoretical energy requirements were determined from the energy required to break a single particle or a thin layer of monosized particles by compression or by a single impact from an impact-testing device. King, Tavaras and Middlemiss (1997), in a paper titled "Establishing the energy efficiency of a ball mill" described such a test. These batch single-breakage tests generally do not duplicate the continuous-breakage process in the comminution machinery used in ore concentrators. Operating efficiency The currently available crushers and grinding mills are fed at a controlled continuous flow rate, and they impart the breakage pattern needed to produce the desired size reduc¬tion. While theoretically inefficient, they are the most practical comminution machines available. The operation of this machinery is relatively simple and can be controlled with available control systems. The essential factors in determining the operating efficiency of comminution machines are energy, as consumed in the machinery, and the required energy, as determined from test work. Bond work indices, obtained from bench-scale or pilot-plant crushability and grindability tests are used in the following Bond equation (Bond, 1960) to determine the energy required to produce the required size reduction

Jan 1, 1999

By Amanda Elioff

Success of the Gold Line Eastside Extension rail tunnels in Los Angeles has prompted Metro?s planning for two new rail lines to include underground alternatives. The Westside Extension Transit Corridor alternatives include up to 17 miles of subway to be constructed in soft ground. The routes will require construction in Los Angeles? ?Potential Methane Zone,? not considered for subway construction until recently. Slurry face TBMs will likely be specified. The Regional Connector, through the downtown area, includes one underground alternative with 1.7 miles of tunnel as well as three underground stations in soft ground and rock. Challenges will include tunnel and station construction under narrow streets. This paper will describe the alternatives, planning, geologic conditions and tunneling concepts for both planning studies.

By A. Tsouchlaraki

The physical relief is a variable of utmost significance in the course of the analysis, evaluation, design and management of the visual environment. In this sense, there are cases where it would be desirable to isolate the relief from the other elements making up the visual environment and to investigate its visual value separately. Such cases include the technical works that cause major and permanent alterations to the relief, as well as the works, of which the spatial arrangement depends on the morphology of the ground. Slopes, distances, hypsometric difference values, viewsheds are elements of the relief that affect the visual value of a landscape, but also the ability of a particular landscape to accept and absorb new activities. This paper describes an evaluation and prediction model of the visual value of the landforms. A questionnaire survey takes place in order to investigate the public preference, using a sample of 221 persons in the broader area of Athens. The means used to demonstrate the various forms of reliefs are 32 perspective digital relief images. Following this and in order to investigate the elements of the relief that affect its visual value, 20 quantitative indices were developed and examined so as to select the best ones. Linear prediction models of the visual value were investigated from the previous elements, through a regression process. The applications of the proposed model in physical environment planning are many, such as the prediction of visual impact by arranging works that alter the relief of a region, as it happens in mining, metallurgical and waste disposal sites.

Jan 1, 2005

By S. D. Bechtel

Bechtel Civil and Minerals, Inc., one of the Bechtel group of companies, is a large engineering and construction firm that services the mining industry, among others. The firm's head, S. D. Bechtel Jr., comments on how his E&C company is dealing with the recessionary economy. First, he offered a historical perspective. About a half century ago-in the middle of the Great Depression-W. A. Bechtel and several business partners drew up a fixed price bid to build the Hoover Dam. At that moment in history, the W. A. Bechtel Co. was a modest success, but the times were troubled and uncertain. Money was scarce and a lot of contractors across the country were one project ahead of bankruptcy. The bid for Hoover was a make-or-break proposition for Bechtel, and it turned out successfully. The Hoover Dam was a no-frills operation in an isolated and harsh environment. There was plenty of hard work, long hours, and not many amenities. Controlling costs was critical. Everyone knew what had to be done, and why and what the consequences were. Today's Challenge Bechtel is now a bigger, more complex organization whose management views the current economic recession as a challenge to be met in much the same way W. A. Bechtel met the challenge of the Hoover Dam: by pulling together with a sense of purpose and direction. In many respects, Bechtel's situation today has a number of parallels to that which faced my grandfather. The company is eminently successful, but times are tough and there are plenty of signs that they could get tougher. My grandfather bet on the Hoover Dam to insure the future health of his company and I think we can work together again in that same tradition, make some tough decisions together, and the company's future can be just as promising. The first and most important requirement is to make certain that everyone understands the situation. The Bechtel group of companies are in an excellent financial position now. Its workload hit an alltime high in 1982 and it is well positioned in its principal markets. But the next two years may be critical for the company. Traditionally, Bechtel's work load lags behind general developments in the economy. Although many of its clients continue to suffer serious business difficulties, Bechtel is only beginning to feel the impact. The worldwide market for basic metals remains soft; relatively low prices and abundant supplies of oil and gas have flattened the petroleum market and made once promising synfuels projects economically unattractive; utility clients are still caught in the vise between overregulation and escalating costs. And persistently high, long-term interest rates have made capital investments expensive and difficult to justify. The company maintained a healthy workload through 1982. In some areas it has had little new work and consequently has been forced to lay off some staff as projects have been canceled or concluded. In other areas new work has tided the company over and more people have been hired. But new work bookings have fallen off, creating some uncertainty for the near future. 1983 requirements are clear, although seemingly contradictory. Belt tightening and cost reduction are necessary for Bechtel to remain healthy and competitive, enabling it to handle a possible further downturn with a minimum of turmoil and dislocation. At the same time, we need to allocate resources and funds in areas that will keep us positioned for the turn-around marketplace.

Jan 2, 1983

The Coeur Rochester Mine is one of the largest and lowest cost primary silver mines in the United States. In January, the mine surpassed 3.1 kt (100 million oz) of historic silver production. Rochester is owned and operated by Coeur d’Alene Mines, the world’s largest primary silver producer. Rochester is the world’s seventh largest silver mine. It also produces gold — more than 31.1 t (1 million oz) in historic production. Cash operating costs have averaged 8 cents/g ($2.58/oz) of silver since operations began in 1986.

Jan 1, 2004

By H. Douglas Dahl

Thank you, Don Gentry, for your generous introduction. It is not adequate simply to say that I appreciate very much the vote of the Award Committee putting forth my name as the winner of the 1992 Daniel C. Jackling Award. To look at the list of previous Jackling Award winners is a humbling experience. The Society for Mining, Metallurgy, and Exploration has been blessed with some exceptional members over the years, and I feel privileged indeed to be included among the Jackling Award winners. During the years of my education at Penn State, my field of specialization was mining engineering, with particular emphasis in my master's and Ph.D. work on rock mechanics. But my career has not been quite so tightly focused as that. I have been involved with coal mining in all its variety - its technical aspects, both theory and practice; and its business side, dealing with management and labor, accountants and lawyers, politicians and environmentalists. And I have also been involved with related fields - construction; exploration; barges, railroads, ships and docks; supply houses; the coke business; you name it. Coming from that practical background, I believe it is most appropriate that I talk with you today about some practical matters. But I will not advise you today how to mine coal or protect roof in a hard-rock mine. You fellows know how to do that. The practical matters that I have in mind relate to policy - national policy. I will acknowledge immediately that national policy is often much less than practical, but bear with me as we explore the subject together. I am reminded of a supervisor I had early in my career. He very strongly advised me, back in 1961, to "get involved in the political process," for without objectivity injected into our national policy making, we will become a second-rate economic power. I have selected as the subject of my remarks today, "Coal and the de facto National Energy Policy." There is an energy policy relating to coal, a de facto one, and it's the one we see as a result of regulation, attitudes and culture from our nation's capital. This de facto policy is the one we in the coal business live with every business day. My thesis is very simple - Coal is, in fact, a vital part of our national energy policy and will remain so, as a practical matter, no matter what politicians may do to us, or not do to us. Coal will prevail - that will be the happy ending to my story in which, of course, we are the good guys in the black hard hats. But first, I must flesh out the plot with some other characters and with some threatening activities. There are five main characters in my story: in order of appearance - Perpetual Politics, Rampant Regulation, Selective Science, Electrification and Confident Coal. The time: the present. Perpetual Politics is always a threat to coal. When you cross the Capital Beltway into Washington, D.C., check your wallet and your gold fillings, because you're not likely to run into any friends. On Feb. 20, 1991, just over one year ago, President Bush presented to Congress his National Energy Strategy. It's a thick document of more than 260 pages, with discussions on securing our future energy supplies, increasing energy effi-

Jan 1, 1993