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By S. Koro

The current economic climate of low commodity prices and increasing costs has put a lot of pressure on mining companies to ensure their operations will survive through the current economic downturn. While history tells us that the cycle will turn around and prices will go back up again, how many mining companies will be left to take advantage of the next upturn? On average in Australia, the maintenance of mining equipment accounts for up to 50% of operating costs; which equates to nearly $15bn per year. In addition to trying to boost productivity, mining companies are also putting a lot of pressure on reducing costs; all with the intention of maintaining/increasing profit margins and thereby keeping shareholders ?happy?. The whole premise of our economy is based on ?growth? and ?profits?. Movements in the market place force mine owners to ?react? to short term fluctuations. And if that movement is downward; operations people at the sites are forced to start reducing costs. Is this cost reduction done in a logical, systematic way where all risks (short-, medium- and long term) are considered? Invariably, the answer is no! Short term ?fixes? are normally implemented with little, or no, regard for medium- and long-term impact. And the reason for this is that management is not fully focused on the long term; focus is mainly on survival. Decision making is driven by shareholder sentiment and history tells us that this is largely short-term. So given these paramteres to work within, what role can ?Asset Management? play in assisting management to meet shareholder and market requirements whilst still maintaining long-term viability of their operations (to the long-term benefit of shareholders dare I say). As maintenance costs account for nearly half the operating costs of mining companies; the ?smart? management of assets is not only crucial; it is essential for survival in today?s economic climate. What is asset management? Asset Management, according to the UK-based Institute of Asset Management (IAM) is ?the systematic and coordinated activities and practices through which an organization optimally and sustainably manages its assets and asset systems, their associated performance, risks and expenditures over their life cycles for the purpose of achieving its organizational strategic plan.? How important is asset management in today?s mining companies? IAM goes on to say: ?This definition of asset management represents a significantly greater scope than just the maintenance or care of physical assets, and is closer to the central purpose of an organization. Good asset management considers and optimizes the conflicting priorities of asset utilization and asset care, of short-term performance opportunities and long-term sustainability, and between capital investments and subsequent operating costs, risks and performance. ?Life cycle? asset management is also more than simply the consideration of capital costs and operating costs over pre-determined asset ?life? assumptions. Truly optimized, whole life asset management includes risk exposures and performance attributes, and considers the asset?s economic life as the result of an optimization process (depending upon the design, utilization, maintenance, obsolescence and other factors).?

Feb 23, 2014

By William Gleason

"Sometimes it’s the smallest things that make the biggest difference. In the world of mining, erosion can lead to small cracks, which can then lead to bigger problems that, over time, can eventually lead to a catastrophic event. However, when managed correctly, as in the case of the Manefey Slide at the Bingham Canyon Mine in Utah, the damage can be minimized.Numerous industry conferences, technical papers, studies and resources are dedicated to these issues each year, but what is sometimes overlooked is how the erosion of personal ethics can also have life-changing effects.At the 2019 SME Minnesota Conference, April 15-17 in Duluth, MN, two inmates serving their respective prison sentences at the U.S. Federal Prison Camp in Duluth spoke to the conference about how small cracks in their ethical foundations grew over time, eventually leading each man to his new address at the minimum-security facility.The men’s full names were not released and they were introduced as Jeff and Tony. Other than the matching green uniforms, both middle-aged men could have fit in with the rest of the crowd. They are well-educated and articulate whose career paths eroded thanks to greed and careless decisions.Tony, a licensed professional engineer, enjoyed a successful career working in contract oversight for the U.S. Department of Defense. Jeff is a former senior vice president of investments who ran a well-respected investment management team. Both spoke openly about the mistakes they made and emphasized that their crimes were not flagrant violations of the black and white rules but grew from ethical violations that live in the gray area between black and white, and right and wrong.Working in contract oversight for the U.S. Department of Defense (DOD), Tony said he was befriended by a wealthy man who was generous with his money. As Tony told it, a few meals with this man led to a few trips to casinos and eventually to gifts of money. The donor did not ask for anything in return, and at the time, Tony said he did not think that he was doing anything wrong. He admits now that the perception of a high-ranking officer in the DOD accepting gifts is not a good one, as it could be construed as the donor might have been trying to gain favor for future contracts; which is how it was presented in court by the prosecution team."

Jun 1, 2019

By C. L. Wilsey, K. M. Oakes, W. J. Reich, M. J. Protani

The time frame required to complete the National Environmental Policy Act (NEPA) process for a new mine or the expansion of an existing mine can range from nine to 24 months, or even longer. The time frame will vary depending on whether an environmental assessment (EA) or an environmental impact statement (EIS) will be completed Completing properly designed baseline studies to collect natural resource data to support the EA or EIS prior to the start of the NEPA process can shorten this time frame. In this paper, a two-year natural resource baseline study by Homestake Mining for the Ruby Hill Mine, Eureka County, NV, is used as a case study to describe how a properly designed and executed natural resource baseline study streamlined the NEPA process.

Jan 1, 2003

By P. D. Rao, D. E. Walsh

A pilot-scale study was performed to evaluate the potential for gravity concentration of gold from -13 mm (-1/2 in.) crushed ore from Ester Dome, AK. 9.04 t (9.94 st) of crushed ore were sampled and processed through a Pan-American jig-Wilfley table pilot plant. Plant products were sampled for assay and material balance calculations. Gold recovery through one stage of jigging and two stages of tabling was 17.4% at a concentration ratio of 615:1. Concentrate grade was 766.3 g/t (22.4 oz/st). The feed grade to the plant was calculated at 1.71 g/t (0.05 oz/st). Jig tailings, primary table tailings and secondary table tailings grades were 1.44 g/t (0.042 oz/st), 1.30 g/t (0.038 oz/st), and 5.47 g/t (0.16 oz/st, respectively. Significant coarse, free-milling gold values were shown to remain in the, jig tailings. Concentrate mineralogy is discussed.

Jan 1, 1992

By Wenming Wang, Edgar E. Vidal, Scott A. Shuey, Patrick R. Taylor, Judith C. Gomez

Introduction In modern society, vanadium is defined as a strategic metal. Some 90% of the global consumption is used as an alloying agent for carbon steels, tool steels, and high-strength low-alloy steels (particularly for pipelines). Advanced titanium-aluminum-vanadium alloys are seeing application in the aerospace industry. Small but ever growing amounts are finding application as catalysts or in electronics. New uses are continually being discovered for this metal. One example of a new application is the vanadium-redox battery for use in generation plants and back-up power sources. Vanadium is found in a large number of minerals, of which the most important are carnotite, roscoelite, vanadinite, mottramite, and patronite. Just over a third of the world's vanadium is produced as a primary product; the balance is a by-product of the iron and steel, oil refining, power generation and uranium enrichment industries. Vanadium can also be sourced by recycling spent catalysts from the petrochemical industry and ash produced by the combustion of oil emulsion in power stations. However, recycling activities are believed to account for only a small amount of total world supply. Vanadium is recovered from these ores largely as the pentoxide (V2O5) [1]. The major sources of vanadium-bearing magnetite ores are scattered throughout Australia, China, Russia, and South Africa. Current estimates of world’s Proven & Probable vanadium reserves are of the order of 41.3 million tones [2, 3]. Commercial vanadium-bearing titaniferous magnetite deposits can be found in Kachkanar, Russia; Pan Zhihua, China; Bushveld, South Africa; and Windimurra, Western Australia [4]. Other deposits have been found in New Zealand, Canada, and India, among other countries. Vanadium consumption in the steel sector has increased some 7% per ton of steel over the last 10 years as new alloying applications have been found to improve steel's strength-to-weight ratio. Future demand from the aerospace and nuclear industries for non-ferrous vanadium alloys such as titanium and super-alloys is also likely to grow. Vanadium is usually added in the form of ferrovanadium, a vanadium-iron alloy. Vanadium compounds, especially the pentoxide form, are used in the ceramics, glass, and dye industries, and are also important as catalysts in the chemical industry. While established approaches may be used at an industrial scale to treat vanadium-bearing titaniferous magnetite ores in several countries, new alternatives are being developed worldwide. This review will give short overview of the treatment of vanadium-bearing titaniferous magnetite ores, an overview of direct reduction and direct smelting processes and an approach to determine technical alternatives for the property.

Jan 1, 2005

By H. M. Garrett

Dr. Ft: L. Handy of Iowa State University's Engineering Experiment Station very handily reduced the relatively complex cement making process to ultimate simplicity: "Take two cups of crushed limestone; add one-half cup of clay or pulverized shale (plus perhaps some sandstone or iron ore; depending); mix thoroughly and grind up fine. Bake in white-hot oven at about 2,600 F. Cool. Add a tablespoon of gypsum: and, again, grind very fine. If you can do this for about a penny a pound, you can almost compete.' Before Dr. Handy's time, is the early days of the U. S. Cement Industry, from 1817 when the Erie Canal was started to 1895 when the first rotary kiln was built, this was the recipe, more or less. Dr. Handy's raw materials were deposited in a natural "cement rock" found in the Hudson, New York and Lehigh, Pennsylvania valleys. At first the natural rock was pulverized (not ground fine) and interlayed with wood for "baking" at about 1,800° F in a batch process vertical shaft kiln or beehive oven; then the calcined pozzalonic (lime and silica) product was cooled and ground fine for shipment in wooden barrels. Later, in 1871, true portland cement was made. The same natural rock was ground fine to make briquettes; interlaced with wood or coal in the "Beehives"; and baked at a clinkering temperature of about 2,6000 F to produce clinker (calcium silicates) which was ground fine for sale. In those days, the crude cements dropped in price from over 1 cent to 1/2 cent per pound. In 1895 the rotary kiln introduced-continuous instead of batch processing. The countercurrent process allowed the same raw materials (now finely ground to about 80% minus 200 mesh like face powder) to be fed at one end of the rotary kiln. Heat from a coal burner was introduced with combustion air at the other end to produce the requisite clinkering temperature. The clinker product was discharged for atmospheric cooling, mixed with gypsum, and again ground fine as face powder. The cement was sold primarily in barrels, later in jute or cloth bags, then paper bags, and now primarily in bulk truck and barge carriers. The price dropped to a 1/4 cent per pound by 1910, but with recent inflation it now sells for 2 cents per pound.

Jan 1, 1978

By A. R. Laplante

In this paper, the performance of the Knelson Concentrator and of the batch and continuous Falcon Concentrators are compared. The units are based on different operating principles, and perform quite differently. The Knelson yields very high free gold recoveries over a wide size range of both the recovered and rejected species. It is less effective in recovering very fine (<15 μm) or very flaky gold, as encountered in flotation feeds, concentrates or tails. It is the preferred unit for gold recovery from grinding circuits. The batch Falcon is effective in the fine range, typically less than 37 μm for gold. Its recovery zone is quickly saturated when there is significant heavies in the feed. It works best as a pre-concentration unit, or when sulphide content is low. The continuous Falcon is a versatile unit which is capable of recovering fine heavies (density down to 5 g/cm 3), especially from coarser gangue.

Jan 1, 1993

By D. Collins, J. Winfield, V. Gangrade, B. Slaker, S. Braganza

"Researchers at the National Institute for Occupational Safety and Health (NIOSH) are investigating the unique pillar stability issues associated with room-and-pillar mining in dipping underground stone mines. The objective of this paper is to study the post-blast impact in and around a pillar, using microseismic monitoring. To accomplish this, a microseismic monitoring system has been installed at a dipping underground stone mine in central Pennsylvania. The microseismic system is comprised of 18 uniaxial accelerometers; 12 sensors are installed in a single pillar and 6 sensors are installed in the surrounding area. More than 4,400 microseismic events have been located near the study pillar following the blasts. The number of triggers increased significantly following the blast, and the trigger rate in the first five minutes was 60 triggers per minute and three triggers per minute over the next three hours. The processing of high-quality triggers indicated a large number of low magnitude microseismic events near the blasting face. The event locations were identified more accurately by using a 3D-velocity model, with an average 9 m expected location accuracy for this array calculated using the system data. Seismicity was absent from the core of the pillar, but significant numbers of events were found following cutter roof along a crosscut as it was developed as well as in the location of a rib failure event. Additionally, the events were located in the roof, showing high number of microseismic events within 0–10 m of the roof line compared to 10–30 m above the roof line.INTRODUCTIONGround control stability is essential to any mining operation for ensuring mineworker safety and health and preventing catastrophic failures of underground structures. The National Institute for Occupational Safety and Health (NIOSH) has conducted research in stone pillar design and has established fundamental pillar design guidelines for the underground stone industry, which resulted in the development of the S-Pillar program (Esterhuizen et al., 2011; Esterhuizen and Murphy, 2018). However, the data that makes up the S-Pillar database consists of shallow depth, flat-lying, single-level mining operations. Therefore, to expand this dataset and to develop guidelines for challenging conditions such as dipping and multi-level mines, NIOSH is currently conducting detailed pillar response investigations at mines with these characteristics. The study is being conducted using multiple research approaches, including seismic modeling and tomography, numerical modeling (Sears et al., 2019), stress monitoring, and LiDAR-based laser scanning (Slaker, Murphy, and Winfield, 2019). This paper discusses the findings from the microseismic monitoring system installed at the Pleasant Gap Mine, a steeply dipping underground limestone mine in central Pennsylvania."

Jan 1, 2019

By J. Noll, A. Miller, J. Volkwein, C. Pritchard

Hecla Limited, Magee Scientific, and NIOSH have combined efforts to evaluate an in-situ air filtration system for use in an underground mine environment. The purpose of the collaboration was to determine the efficacy of such a technology for reducing the concentration of airborne diesel particulate matter (DPM), with the aim of improving air quality in underground hardrock mines. A secondary goal was to evaluate the use of an Aethalometer as a means of real-time measurement of black carbon as a surrogate for DPM. The evaluation included measuring the DPM-capture efficiency of the filter when it was pre-loaded with dust. Toward this end, rock dust was introduced at the filter inlet to create a dust layer on the filter surface, with the intent of providing improved capture of the much smaller DPM particles. The filtration efficiency for DPM was assessed by comparing measurements of DPM taken at the inlet and outlet of the system, using both real-time and time-weighted-average approaches. The real-time measurements were performed with the model AE33 Aethalometer® made by Magee Scientific. The results of the NIOSH 5040 method analysis were used to assess the effects of the system on time-weighted-average concentrations of total carbon. Results showed a reduction in DPM concentrations in the range of 82%-89%. While the calculated efficiencies based on the two different measurement methods were similar, the DPM levels reported by the Aethalometer were higher, possibly due to differences in the performance of the size-selectors used for the two methods (impactors versus cyclones). More research is required to develop a robust correlation between the two methods, to support the use of the Aethalometer for future mining applications. The advantage of the Aethalometer is that it can measure and record DPM levels for weeks at a time, and can be directly connected to a mine monitoring system, potentially at multiple locations. Ideally such data can be used to initiate the startup of the filtration system should DPM concentrations reach an action level. This work demonstrated that in-situ filtration systems, modified to collect DPM and coupled with real-time monitoring, show promise at reducing DPM concentrations in the mine environment.

Jan 1, 2016

By LeRoy D. Loy

The coal mining industry must be able to compete with alternate sources of fuel for the utility and industrial customers. If the industry is unable to control transportation costs, either due to government interference, or for other reasons, then mining costs must be kept down. Australia, South Africa, Canada, (and later Colombia) will take larger shares of the export market if mining costs are not kept competitive. The government&apos;s environmental regulations must be met without incremental increases in mining costs. Entrepreneurial instincts must be retained by the industry to provide for their investment in the future. What are the Problems with Existing Research? Government funding for coal mining research has been reduced or virtually eliminated. BCR (Bituminous Coal Research) is now a membership- supported organization, but its primary focus has been on health and safety-oriented research. BCR, however, is now attempting to widen its scope and conduct other types of research. There are almost no funds in EPRI&apos;s (Electric Power Research Institute) program for coal mining research. Large mining companies do some research for their own purposes and needs, but this is proprietary and therefore results are not shared with the remainder of the industry. The mining industry as a unit is not undertaking productivity (systems) oriented research in any common or cohesive manner.

Jan 1, 1983

By Virginia T. McLemore, Abena S. Acheampong-Mensah

Critical mineral endowment of mine wastes in two mining districts in New Mexico (Copper Flat at Hillsboro and Carlisle-Center mines in the Steeple Rock district) will be characterized and estimated. “Beta-testing” of USGS procedures was performed. Potential critical minerals at these deposits include As, Bi, Te, Zn, Co, Ni, Mg, Mn, and fluorite. pH and particle size of samples were analyzed to determine weathering and migration potential of heavy metals. Soil pH was also measured to determine the potential for Acid Rock Drainage. The pH of the waste rock piles ranged from 3.66 to 5.67 which indicates fine- grained pyrite or sulfide oxidation. The samples collected from the tailings however, showed a different range of pH, from 6.30 to 8.62, probably due to the presence of carbonates. Difference in particle size fractions and its distribution along the slope are generally influenced by natural occurrences (e.g., gravity and pre-mining hydrothermal alteration) and operational activities such as material piling or dumping. Future work includes analyses of mineralogy and particle size correlation and estimation of critical mineral endowment of these mine wastes at New Mexico.

Feb 1, 2024

By Thomas Hard

A description is given of a new facility processing blast furnace slag into a high quality cementitious material to be used as an ingredient in concrete for general construction purposes. A brief history of the process is given, followed by a detailed discussion of the water granulation system and the methods used to transport and dewater the granulate. Environmental advantages of handling slag away from the blast furnace by water granulation are included.

Jan 1, 1983

By S. L. Jung, T. L. Nichols, K. Prisbrey

The problem was to evaluate the on-line detection of rock properties through acoustic emission sensors. Acoustic emission sensors, when attached to crushers, grinders, and roof bolters, are robust, economical, and relatively maintenance free. Our objective was to relate acoustic emissions to rock fracture mechanisms, including micropore closures, linear elastic deformations, and crack propagation. We evaluated acoustic emissions from steel jacketed rock cores during indentation tests. In addition we attached sensors to the rotating shaft of a rock bolter drill. A back propagation neural network "learned" rock fracture characteristics and rock type with 99% classification accuracy. A neural network&apos;s calibration and computational abilities suggest better acoustic emission sensor capabilities.

Jan 1, 1993

By P. W. King

The performance of the versatile McNally Wedag horizontal vibratory centrifuge for dewatering ultra fine 0.5 x 0.15 mm (28 x 100 mesh) material has proven to be success¬ful and the results presented herein will examine its capabilities in terms of capacity, solids capture, product moisture, effluent solids, and size analysis. Centrifugal dewatering of fine refuse has proven t to be another application for which this unit has performed exceptionally well.

Jan 1, 1985

By Charles L. Allie

In June, 1980, Reserve Mining Company completed a 370 million dollar construction project which included process modifications required to reduce the silica content from nine to five percent by weight and increase the iron con- tent of Reserve&apos;s pellets from 62.5 to 65.8 percent by weight (dry basis); process modifications and additions required to implement "best available technology" water quality controls; and installation of "best available technology" air emission controls. The new process began operation on June 24, 1980 and is being optimized to meet design objectives. Dry cobbing, fine screening and flotation additions to the concentrating process have reduced the silica content of Reserve&apos;s pellet from nine percent to five percent by weight. The process reclaims and reuses all process waters, stores all tailings in a zero discharge tailings basin and meets all air emission standards.

Jan 1, 1980

By S. Tuylu, D. Adiguzel, U. G. Akkaya, A. Bascetin

"One of the main problems for storing of the tailings is acidity occurrence due to several factors such as existence of sulfuric minerals and also the pollution in seepage waters by mobilization of metal ions, which holds great risks in terms of environmental regulations. Because of these specified reasons, tailing materials to be used in a SPD formula should have comply with some specifications. Among these properties; oxygen content, temperature, matrix suction and pH are the most important parameters. In the study, the relationships between the parameters mentioned are investigated to reveal optimum paste design layout. The lowest amount of seepage water obtained from the paste layers in the pilot cabinet was found as 2150 ml from 3rd layer. As for the maximum seepage water and the average of the all 11 layers were found as 4909 ml from 6th layer and 3273 ml respectively. The reactions occurring according to the oxidation, as seen at seepage water of second and third layers, decreased the pH of system to the under of 7 value. Additionally, when the seepage water of first layer’s EC value is 2.93 mS/cm, the EC value of second layer is increased at 3.54 mS/cm. The other parameters are evaluated with the obtained results of the tests to determine the optimum storing conditions for SPD.INTRODUCTION Conventional waste disposal methods, although widely used, pose great environmental risks. One of the most important issues is acid mine drainage (AMD). Tailings of metallic mines contain heavy metals, aggressive chemicals and hazardous materials. In the presence of oxygen and water, an oxidation reaction can occur, causing a decrease in pH of the environment, and heavy metals that are present in the environment can dissolve easily. Subsequently, heavy metals can pollute underground water basins, creating a great amount of danger for the ecology and potable water resources. Another important risk associated with conventional waste disposal methods is accidents related to the waste dam. Higher volumes of water and tailings (usually 15% solids and 85% water by weight) are sent to waste dams, making it very difficult to control the stability of the dam under conditions such as static and dynamic loads (seismic activities, vibrations caused by blasting, etc.), flooding, and seepage. In case of an accident or failure, the spread of great amounts of mud containing hazardous chemicals and heavy metals can harm the environment of the dam site significantly (Bascetin et al., 2014). In the paste technology, depending on the type of ore, tailings used in the paste mixture can contain sulphide minerals (such as pyrite and pyrrhotite). These minerals are known to be reactive with water and oxygen to produce acidity (sulphuric acid)."

Jan 1, 2015

By Wern-ping Chen, Joseph Pratt, Thomas G. Brueckner, Tracy K. Lundin

To address and mitigate discharges from combined sewer overflows in the Providence, Rhode Island area, the Narragansett Bay Commission completed a comprehensive Combined Sewer Overflow (CSO) Facilities Plan in 1993 which included a series of deep rock tunnels. Since completion of preliminary design of the program in 1994, the program has been reconfigured in response to the Environmental Protection Agency’s (EPA’s) new CSO policy. The currently proposed system consists of a deep rock tunnel with two tunnel stubs which will provide230,000 cu m (62 million gallons) of storage at depths of up to 90 m (300 ft). This paper discusses the revised 5 km (3 mile) long deep tunnel system.

Jan 1, 1999

By Dan Brunner, Scott Thomson, Ben Lyddall, Duncan Thomson

Geosensing is used in oilfield drilling in conjunction with geophysical tools to support characterization of rock properties, geology, and reservoir conditions. This technology is now available to the mining industry and has been successfully applied to underground in-seam directional drilling in Australian coal mines for geologic exploration and methane drainage. The system utilizes a range of drill rig and wellhead mounted sensors which, combined with analytical software, produce real-time data from which 3D spatial features can be accurately modelled significantly in advance of mining. This innovation greatly expands on the information obtained from current in-seam directional drilling practices and provides for improved characterization of coal seams, including soft and weak zones, locations of geologic discontinuities, and analysis of formation flow. This paper provides a description of the geosensing system and the interpretation of actual data from long in-seam directionally drilled methane drainage boreholes at mines in Australia, and discusses how this system increases the value of directional drilling as an exploration tool for the coal mining sector, and the evaporite and hard-rock mining sectors where directional drilling is also applied.

Feb 1, 2024

By Robert Moore Lewis

Extensive exploration is being undertaken throughout the world in search for heavy minerals, particularly rutile and other titanium minerals. The federal government is sponsoring research involving rutile ores and recovery of stockpile-grade concentrates from domestic sources. Producers are being forced to turn to deposits with a heavy mineral content as low as 0.50% (essentially rutile and zircon). The North Carolina State University Minerals Research Laboratory investigated the possibilities of recovering heavy minerals from the amine tailings of the Texasgulf Inc.&apos;s phosphate plant at Aurora, North Carolina. One laboratory beneficiation procedure using gravity, electrostatic and magnetic processes, resulted in the recovery of 78.7% of the heavy minerals in the amine tailings. Based on this percentage recovery and the present rate of phosphate mining, approximately 13,000 tons per year of heavy minerals (principally ilmenite and zircon) with a potential value of approximately $1,045,000 (1977) could be recovered. The economic potential for recovery of these heavy minerals appears to be favorable. A flotation procedure for up-grading the heavy minerals content in the amine tailings has been developed at the Laboratory, which could allow for concentration of heavy minerals and storing them in tailings area other than main tailings for future processing.

Jan 1, 1978

By Richard Newcomb, Michael Rieber, William A. Vogely

INTRODUCTION The solid fossil and nuclear fuels, but especially uranium, are given prominent, indeed leading, roles by energy experts in most long range estimates of world energy futures. Optimistic forecasts are inspired partly by the disproportionately large solid fuels resource base compared to present rates of consumption or to oil and gas resources, and partly by the vision of inexpensive high technology applications. Such a view overlooks the fact that while resource- use disparities and new technologies give allure to the promise of the solid fuels, they do not guarantee cheap solutions to the basic problems of solid fuel uses: viz., their relatively difficult conditions for efficient ignition and control, including the management of environmentally acceptable residuals disposal. Contrary to the varied versions of this optimistic hypothesis, this paper shows that a great many persistent economic and technical problems interfere with such a simple inference. These act as constraints which qualify or dispute much of the national energy policy based on existing modeling of solid fuel requirements and optimistic engineering evaluations. The assumptions and techniques of such exercises are sometimes at fault. As often as not, however, the distortions created in open market fuel com- petition due to misdirected national energy policies themselves are to blame for misdirected efforts. A number of interesting implications result. Among them are the distinct possibility that the low technology applications will dominate, so that more direct coal and less synfuel or nuclear use will occur; that, accordingly, exhaustion rates for uranium will be low, that the most extensive growth of solid fuel through 2000 will be in conventional pulverized coal cumbustors, and that the traded share of the world coal bum will be much larger than predicted. These trends will place much more pressure on oil and gas prices than forecast by most experts. On the way to these findings the paper demonstrates that solid fuel resource adequacy in situ, balanced against the projections of demands as capacity requirements, mean little as conventionally measured by years to exhaustion or potential supply schedules. Indeed, all stock concepts of demand requirements or of fuel re- sources must be tied to the paths of the unit costs and the deliverable prices of all substitute fuels and systems over time. This requires a dynamic analysis of supply and demand, integrated with geological and engineering constraints, to provide insights into the multiple modes of market and product substitution. Market forces rather than technical promise will determine the allocation of the solid fuels. Moreover, the equilibrium paths of individual fuel prices and market shares are not easily simulated by general or network models, and decision makers will continue to rely on the partial, local comparison of alternatives in their choices of fuel systems at any time. &apos;The economics of the solid fuels differs from that of other energy sources in important ways relating to their form in use, conversion efficiency, (dis)economies and externalities. Petroleum and gas are in a more convenient form for

Jan 1, 1985