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By Marcie A. Greenberg

The Fence Lake Project is located in the Salt Lake coal field, an extension of the San Juan Basin. Geologic formations exposed in the Project area range in age from late Cretaceous to Quaternary. Coal is encountered in the Moreno Hill Formation (upper Cretaceous). Salt River Project (SRP) followed the basic textbook approach for the exploration, regional appraisal, detailed reconnaissance, detailed surface appraisal and three dimensional sampling (physical exploration). SRP is exploring this property as a potential fuel source for the Coronado Generating Station. Therefore, for the physical exploration stage, the quality sampling program was designed from a utility company viewpoint to determine possible impacts to the Station. Exploration drilling was completed in spring, 1982; September, 1982, and summer, 1984. Engineering, environmental, and land acquisition studies were added in the Summer, 1984 Program to more closely evaluate the potential Fence Lake Project coal supply option for the Coronado Generating Station. Studies, including drilling, are ongoing-at this time.

Jan 1, 1984

By J. D. Campbell

"Coal is one of Alberta's major fuel resources, but its distribution, especially in the flat plains region, has been somewhat obscured by surficial deposits. After a period of neglect, easily strippable plains coal is presently approaching a position of dominance in electrical power production, a position it is likely to retain for a number of decades in the face of strong competition from hydro and nuclear power. Accordingly, the Research Council of Alberta has undertaken an inventory survey of the province's supplies of this resource.In the southern part of the province and in the north-central forest-fringe area, some strippable coal is found in the Belly River Formation and its equivalents, but major strippable coal reserves in large areas of central Alberta occur within the Edmonton Formation. The survey is planned on a reconnaissance scale, drilling test holes at 2-mile intervals in selected large areas. It appears to show that, in well-settled regions, large reserves of strippable coal are only to be expected where they have long been known; major presently unknown bodies of coal must be sought in unsettled regions or at depths too great for strip mining. However, such bodies might still be economically competitive with hydro and nuclear power in the production of electric power for some time to come."

Jan 1, 1967

By Robert M. Weidenhammer

For years before the war, Coal had the reputation of being a sick industry. Currently it is operating at peak production and succeeding pretty well in keeping out of the red. But, says Mr. Weidenhammer, it will have a relapse as soon as the war ends unless (1) working capital can be built up; (2) it gets the support of the people and Congress; and (3) a truly long-range national fuel policy is formulated.

Jan 1, 1943

By Dave G. Osborne

With the growing exportation of coal from North America to the Pacific Rim countries and Europe, has come an increasing awareness of the need to determine economically optimized amounts of incombustibles (ash and moisture contents) for the shipped product. Despite the fact that demand bas caused a steady improvement in selling price, particularly for thermal coals, growing production and transportation costs have compelled producers to keep a sharp eye open for ways and means of minimizing the latter since this probably represents the greatest single potential for making savings. Consequently the Coal Industry has become acutely aware of the economic ramifications of eliminating moisture in particular, thereby producing further saving in the cost of transportation of product from the mine to the consumer. There is, however, a lower limit to which dewatering or drying can be taken and this relates to dustiness which is a function of the characteristics of the coal and the methods used for handling and storage during trans-shipment. Overdrying can lead to serious dust losses and difficulties in handling particularly if the coal contains a large proportion of fines. The ways and means for achieving this "happy medium" of optimization in moisture removal are seemingly undergoing gradual modification largely assisted by the following factors. a) Improvement in effectiveness of coal dewatering and drying equipment. b) Improvement in operational availability and utilization of the equipment. c) The development of surfactants, polymer flocculants and other agents which in many cases can be almost tailor made to suit specific applications.

Jan 1, 1982

By J. L. Thompson

The combustion of pulverized coal is a century-old practice. Many people have investigated coal dust and the residual fly ash particles that re-main after combustion. But the combustion process and fly ash formation mechanism are not under-stood. Working at our Maysville, Kentucky lime plant, the Dravo Lime Company Research team has collected samples of partially burned coal dust from the flame of a pulverized coal burner. Specimens were placed in a scanning electron microscope (SEM) equipped with an energy dispersive spectrometer (EDS). Microscopic examination of the particles, together with a large collection of micrographs of lime dust fused to fly ash particles, now make it possible to theorize as to how combustion advances through a piece of coal dust. Coal is a physical mixture of carbon-based compounds interspersed with bits of ash-forming materials, primarily alumina-silicate compounds. The alumina-silicate materials are commonly in angular nodules measuring 100 A to 700 A across their major dimension. It would appear that if the coal particle is in a well mixed gas stream, combustion starts at the surface and advances radially toward the particle center. With poor gas mixing, it is common that combustion moves from one end of a particle and advances on a broad front almost normal to some axis. In either case the combustion process and ash-forming mechanism are the same. As combustion occurs the carbon-based compounds oxidize in a highly exothermic reaction. Heat from the re-action melts the alumina-silicate nodules causing them to flow together and coalesce into an open sponge-like structure. As melting continues surface tension of the liquid and free surface energy causes the sponge-like structure to simplify into fewer, larger pores. Most likely the lighter molecular weight hydro-carbons burn before the heavier species. This means that as the melting ash structure is metamorphosing to a single large pore, there continues to be out-gasing throughout the structure due to combustion. Surface tension will form a spherical piece of fly ash if the ash material is liquid for a sufficient period of time. Out-gasing from combustion of the heavier hydro-carbons will provide internal gas pressure to keep the particle spherical until it freezes.

Jan 1, 1978

By Thomas A. Wheeler

The reagents commercially used in coal flotation and their roles are reviewed and discussed According to their function the reagents are divided into often overlapping groups: 1. Collectors 2. Frothers 3. Conditioning Reagents Frothers have by far the largest effect on the amount of coal recovered They act not only in their traditionally accepted function of “bubble makers”, but in coal flotation they serve in a seldom acknowledged role of collectors. A lab flotation study on four samples of different coal ranks shows how these react to various frother families and proves that no froher is the optimum reagent for all types of coal. The advent of new technology in flotation equipment in the past decade has resulted in various novel designs of column cells, Jameson and Centrifloat™ cells, air-sped hydrocylones, etc. All should require special frothers or blends of frothers to meet their specific needs.

Jan 1, 1994

By F. G. Miller

Over the past 30 years, the coal industry has been continually striving to perfect methods for cleaning fine coal to acceptable ash and sulfur contents while maintaining maximum product yield. The flotation process has been part of this effort and its importance is expected to grow as new utilization technology demands finer and purer coal products. The work outlined in this paper is part of a larger effort aimed at development of new and improved flotation systems for removing sulfur and ash from as-mined coal as well as for producing super-clean coal for future markets. The concepts and data presented are now serving as a basis for designing fine-coal circuits in which improved efficiency is obtained by optimum use of flotation.

Jan 1, 1986

By A. V. Nguye, P. A. Harvey

Previous studies have reported that inorganic electrolytes can enhance floatability of coal. The research has shown that the enhancement, if any, is highly dependent on changes in solution pH, type of electrolyte, and electrolyte concentration. The reasons for this are still not clear. In this study the floatability of coal particles in mono and divalent salt solutions was investigated. The zeta potential and hydrophobicity of the coal was measured experimentally, and a modified Hallimond tube was used to determine the floatability of coal particles by single bubbles, where the collision efficiency was equal to unity. The experimental information was used in conjunction with the Hogg-Healy-Fuerstenau equation to quantify the electrical double layer interaction. It was found that for low electrolyte concentration (less than 0.1 M) solutions the flotation recovery of coal particles was less than that for distilled water, and decreased with increase in concentration. Conversely, at electrolyte concentrations above 0.1 M, flotation recovery increased with increasing concentration. Both of these results are consistent with previous observations, but are inconsistent with expectations when considering the possible influence of electrical double layer interaction. A possible mechanism, based on the existence of the pre-existing submicron-sized gas bubbles, known as bubstons (i.e. bubbles stabilized by ions), present in water in close proximity to the hydrophobic coal surfaces is discussed in line with the early observation of flotation improvements by microbubbles “nucleating” on hydrophobic surfaces. In particular, the dependence of the bubble-particle attachment efficiency on electrolyte concentrations supports hypothesis on the salt-dependent and ion-specific existence of bubstons. However, a theoretical explanation of the transition salt concentration (at about 0.1M) is deficient at present. The existence of these submicrobubbles in close proximity to hydrophobic surfaces is not trivial. They can (as can individual gas molecules or other solutes) mediate and extend the range and magnitude of the attraction between hydrophobic macroscopic surfaces. These bubbstons may explain the curious phenomena of the socalled long-ranged hydrophobic attraction measured with the Surface Force Apparatus and Atomic Force Microscopy, and the slippage at hydrophobic surfaces. Finally, the coalescence of bubbstons affects the rupture of liquid films at a very large thickness (over 100 nm), observed, but unexpected, by flotation chemists.

Jan 1, 2003

By W. Irwin

As a consequence of the oil crisis of the 70?s, the commercial value of coal increased very sharply and an upward trend in coal prices although now less pronounced, continues today. The graph shown in figure 1 illustrates the trend in the F.O.B. price of U.S. metallurgical coal. This trend occurs during a time when mechanized mining is firmly established as a means of production throughout the coal mining world. With modem methods of mining, mechanical cleaning is a necessity and quality control is no longer entirely dependant upon coal face practice. The efficiency of fine coal recovery is of vital economic importance to present day operations and good practice in this field contributes significantly to improving profitability. Numerous processes are available for the duty and this paper discusses one such system, namely the practice of froth flotation.

Jan 1, 1980

By G. H. Harris

The flotation behavior of two high sulfur coals using a non-ionic surfactant as collector from two series of compounds containing oxygenated functional groups was studied in detail using a 2-liter Denver flotation cell. The performance of these reagents was compared with that of an oily collector, namely dodecane. The results showed that at the same coal recovery, a much lower dosage of these non-ionic surfactants was required as compared with that of dodecane. More import was the performance of these compounds as promoters for oxidized as well as un oxidized coal. Mechanisms of interaction of these compounds with the coal are suggested.

Jan 1, 1993

By E. G. Bailey

PLANTS that normally burn coal now able too obtain a substantial increase over their normal supply for their greater power needs, and also additional tonnage for extra storage against the uncertainties of the future. Many plants previously burning oil or gas have already been converted to coal, and those which must yet change to coal will undoubtedly be able to obtain ample tonnage of coal of standard quality at reasonable prices. What a contrast this is to the conditions of 25 years ago, when the shortage of coal and transportation led to prices of $5 to $6 per ton at the mines, and degradation of quality, until the already overburdened railroads were called upon to haul 100,000 ton per day of extra ash alone. This was the result of a runaway market and the loading of gob, slate, and sub-quality coal amounting to an estimated increase in ash of 5 per cent of the total tonnage hauled. The problem of getting increased steam output from inferior coal caused unbelievable reductions in the low normal boiler efficiency of that time and untold labor in firing the hand- and stoker-fed furnaces of that day.

Jan 1, 1942

By J H. Dressel, J. E. Williams

This paper presents a brief review of what coal gasification is, procedures that are available today and processes that may be available in the future. Examples are given as to how the process might be used in power plant applications, the effect on pollution level and power costs, and some thoughts on the added burden that might be placed on mining and coal preparation.

Jan 1, 1973

By Henry R. Linden

The demand for natural gas continues to increase at higher than anticipated rates, partly because of its widening price advantage over most other fossil fuels when the cost of air pollution control is included. However, there are clear indications that natural gas supply from the contiguous 48 states and continental shelves will not indefinitely keep up with this rapid growth in demand. Projections are presented which define the extent of potential deficiencies from the 1970's to the year 2000. Among the sources of supplemental gas - imported pipeline natural gas from Canada and Mexico, tanker import of liquefied natural gas, and synthetic pipeline gas from coal and oil shale - by far the most abundant at potentially competitive costs is pipeline gas from coal. The state of development and relative economics of the various coal gasification processes are reviewed. It is shown that synthetic pipeline gas could become a very substantial market for bituminous coal and lignite at current minemouth prices - 60-70 million' tons of coal for each trillion cubic feet of synthetic pipeline gas produced. This corresponds to only slightly more than the current annual increase is gas demand.

Jan 1, 1969

By R. D. Merer

The production of low- and medium-Btu gas from coal provides a more economic source of energy for most industrial users than pipeline-quality coal gas (SNG), although the latter has received more publicity. The paper reviews existing and advanced methods of coal gasification, with particular emphasis on the production of low- and medium Btu gas for industrial and utility use. Some of the ways in which coal gasification can be integrated into power cycles and industrial plant energy balances are discussed.

Jan 1, 1978

By Carl E. Bagge

It is easy for a coal spokesman to relate to the theme of this meeting--that the decade of the 1970's is pivotal for the mineral industries. For the coal operator, this period is crucial. The coal industry, according to most energy forecasters, must gear its production machinery to meet a sharp rise in the demand for coal--in this decade to sustain inevitable boosts in electricity output, and in the next to start supporting a big new domestic synthetic fuels industry that is already in the formative stage. The logic of that projection flows from a combination of hard circumstances--proved reserves of domestic fluid fuels are dwindling, the hope for bountiful and cheap nuclear power must be indefinitely deferred, and the threat of long-term fuel imports to the national interests is becoming starkly visible. Only coal, with its assets of abundance, security and versatility, offers the nation an adequate and immediate lift out of its current energy crisis. A hard-won expansion of coal production made the critical difference between local power load-shedding and major area blackouts in 1970, the year the energy crisis went public. Coal will have to play that same key role, not just through this pivotal decade but through the turn of the century. But the logic of fuel demand apparently does not always extend to supply. The coal industry has had a huge production job laid out for it by the energy statisticians, but up to now the energy policy-makers have not followed through with the aids and inducements that the coal operator urgently needs to do that job well and completely.

Jan 1, 1972

By B. J. Arnold

Over 600 million tons of coal are handled annually for use by the country's coal-fired power plants. Coal is transported in various ways. overland conveyors. Railcars, trucks, and barges. It can travel short distances or thousands of miles, picking up moisture, freezing, or drying. When the coal is received at the power plant, environmental problems with fugitive dust and further handling problems can arise.

Jan 1, 1989

By Stanley Kesler

The first of two initial 650-mw units of the Paradise Steam Station, located on the banks of the Green River in the south-central portion of the western Kentucky coal basin, is scheduled for operation in late fall of 1962. Location of the site is shown on the map of figure 1. This plant will be the eighth, large-capacity,, modern station built by TVA in a series starting with Johnsonville, operated first in 1951. During that period of 10 years,, unit sizes have increased from a capability of 125 mw to 500 mw at the recently completed Widows Creek Unit 7 addition and at Paradise to 650 mw. This new unit will take its place in a power system that serves an area of some 80,000; square miles with a present installed capacity of over 12,000 mw. Upon completion of the Paradise units and other additional hydro and steam units presently under construction, the system capacity will have reached over 15,000 mw. Projected load estimates indicate that this system will provide a margin' of slightly under 10 percent of dependable capacity above peak demand at that tire. One Paradise 650-mw unit at that time will represent approximately 4 percent of the total system installed capacity.

Jan 1, 1962

By J. J. Wallaert

The decreasing supplies of natural gas and low-sulfur crude oil available for electric power generation in the United States will unquestionably shift the emphasis to nuclear and coal fired steam power plants in the immediate future. Failure to do so will ensure our dependence on mid-east low sulfur crude oil comprising some 70% of the known world reserves, and imported liquid natural gas. By contrast, the United States has 43% of the known world reserves of anthracite, bituminous and semi-bituminous coal and 48% of all known coal reserves of the world including lignite. It is evident, therefore, that coal is alive and well and will continue to be a significant energy source for the production of electricity for many years. Of course, concern for our environment and the development of new technologies will ultimately curtail the utilization of coal for the generation of bulk power, but information released by the National Electric Reliability Council and the Federal Power Commission is worth repeating. In the year 1972 the total capacity of generating units in the United States was 379,552 Mw of which 149,974 Mw, or 39.5% of the total, was produced by coal fired steam turbines which consumed 344,700,000 tons of coal. New capacity additions planned or in construction show that in the year 1981 our total generating capacity will be 843,503 Mw, of which 257,995 Mw, or 30.6% of the total, if from coal only. Translating this increase into terms meaningful to the bulk material handling industry suggests that ten years from now the utility industry will require 590,000,000 tons of coal per year - a monumental task - if we are to sustain our current demand rate for power.

Jan 1, 1973

By William H. Lehr

In recent years, we have witnessed many innovations in the equipment used in handling bulk materials. Not too long ago, any sizeable stockpile of coal or iron ore was attended by one or more material handling bridges. More recently, large stockpiles have been built with mobile equipment of' the earth moving type with bulldozers and front end Loaders being utilized in reclaiming operations. The most recent stocking and reclaiming device is the rotary bucket wheel machine. The early bucket wheel machines built in the United States were developed for the strip mining of coal. We understand that the first American machine was built in the Midwest in 1944. This type of unit was developed in an effort to reduce the cost of removing overburden and to provide satisfactory spoil disposal. As the available coal reserves under shallow cover were exhausted, the cost of removing the deeper overburden with conventional equipment became too great for these operations to continue profitably. The first machine has now been followed by six or seven additional units, the largest of which can handle material at a rate of more than 7000 cubic yards per hour.

Jan 1, 1965

By HOWARD N. EAVENS

DURING the year just closed the bituminous industry has been marked by a continuation of the period of low prices and a steady deflation, accompanied by the closing of mines and the consolidation of small units into larger ones. This pro- gram has marked almost every field in the country, and it bids fair to continue for some time. Some figures recently published for Kentucky show that in 1924 there were 660 mines producing 45,147,000 tons; in 1928 the number had decreased to 537, while production had increased to 61,860,000 tons, and a similar movement is occurring all over the country. Prices throughout the early part of the year were very low, but during the fall and winter the prices received are more satisfactory than they were earlier in the year. One of the leading developments in the marketing of coal during the year was the trade practice movement, which began in the Harlan field, and has now been adopted in the Harlan, Hazard, Appalachian, Logan. Williamson and Kanawha fields. The purpose of this movement is to prevent the shipment of coal except on order, and by the publication of price lists to prevent much senseless price quotation. Where it has been practised the longest this movement has resulted in a considerable degree of stabilization, and, undoubtedly, it will help existing conditions very materially if it becomes universal.

Jan 1, 1930