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By Wen Tao Liu, Tong Tian, Fu Sheng Niu, Xiu Man Liang

In order to address the difficulty of accurate segmentation of froth images of different sizes, a method of froth image segmentation based on highlight correction and parameter adaptation is proposed. First, a machine vision system on a single-cell flotation machine is built to collect froth images. Homomorphic filtering is used to improve the uneven brightness and shadow of the images. Fuzzy c-means (FCM) clustering is then utilized to classify similar highlights that belong to the same froth. After Otsu threshold segmentation, a parameter-adaptive morphological operation is used to extract the marker points and edge bands and correct the froth edges in the original image. Finally, the modified image is filtered by morphological reconstruction, and the highlight mark is used as the local minimum point for watershed segmentation. Three sizes of froth images are segmented in comparative experiments. The results show that the proposed method is suitable for the segmentation of froth images of different sizes. The position of the extracted segmentation line is close to reality, with average over-segmentation and under-segmentation rates for froth images of 2.6% and 6.8%, respectively. The froth image segmentation performance is stronger than that of the other methods examined.

By R. J. Woody

DESIGN of the most economic continuous counter-current decantation (CCD) circuit is based on selection of the number of stages and the wash volume that will give the minimum summation of the following items: 1) Capital and operating costs of the CCD circuit. 2) Capital and operating costs of the precipitation circuit. 3) Value of the dissolved product lost.

Jan 7, 1958

By Randall J. Essex

The Construction Institute of the American Society of Civil Engineers recently published the second edition of a 1997 publication on geotechnical baseline reports. The new publication, called Geotechnical Baseline Reports for Construction, Suggested Guidelines, represents a 2-year effort that adds three new chapters to the original publication, as well as capturing practitioner commentary through two industry workshop sessions. The paper will overview the contents of the new publication, particularly the three new chapters.

Jan 1, 2008

By L. Moyd, P. Moyd

The first commercially available portable gamma ray-neutron beryllium detector, the Rerylometer, was developed by the same group that developed the first practical portable scintillation counter, the Scintillo-meter. This group includes Professor George Brownell, of the Geology Department of the University of Manitoba in winnipeg, and his associates, K. I. Roulston, R. w. Pringle, and R. L. Funt, of the Physics and Engineering Departments of the University of Manitoba. A prototype model was tested in the field by Dr. Brownell during the summer of 1958. Commercial production was undertaken shortly thereafter by Nuclear Enterprises Ltd., of Winnipeg, and a license for manufacture and distribution in the U.S. was granted to Isotopes Specialties Co., of Burbank, California, a division of Nuclear Corporation of America. Early in 1959, we were retained by the 'Mining Division of Minerva Oil Co. to Legin a search throughout North America for minable deposits of beryllium, and to train members of their permanent staff to continue the program. The project included literature sur-veys, interviews with members of various federal, state, and provincial agencies, scanning of our own collection of suites of specimens from various mineral occurrences, and the examination of deposits in the field. The value of a beryllium detector to this program was obvious and arrangements were made to procure one as soon as possible, which resulted in our obtaining and using the first instrument that was produced commercially in the U. S. In addition to the commercially available Berylometer, Mr. William Vaughan and his associates, of the U. S. Geological Survey Geophysics Division, in Denver, have developed and tested several experimental instruments based on the same principles. DETECTOR Principles The detection of beryllium is based on the fact that "hard" gamma rays (1.6 MEV and geater), such as those produced by Antimony convert ordinary beryllium (Be9) to Be8 , with the release of a neutron. The neutrons are counted by a scintillator designed to favor neutron responses while suppressing those of gamma rays. 'The instrument is completely selective for beryllium. No other element can interfere. Instrunlentation The Rerylometer itself, which is cylindrical, is about 8 inches in diameter, 13 inches high, and weighs about 11 pounds. (Figs. 1, 2). The principal components include: 1. A disc of wax to moderate (or "thermalize") neutrons. 2. A boron-enriched polyester-zinc-sulphide fluorescent screen. This material produces strong flashes when struck by thermalized neutrons but only weak flashes from gamma rays. 3. A photomultiplier tube. 4. An electronic circuit, complete with one srnall 71/2-volt dry battery. The photomultiplier tube and electronic circuit convert neutron flashes to electrical impulses, but gamma ray effects are almost

Jan 1, 1961

By R. J. Woody

Design of the most economic continuous counter-current decantation (CCD) circuit is based on selection of the number of stages and the wash volume that will give the minimum summation of the following items: 1) Capital and operating costs of the CCD circuit. 2) Capital and operating costs of the precipitation circuit. 3) Value of the dissolved product lost.

Jan 1, 1959

By AIME AIME

ASIDE from the annual dinner-dance, the two outstanding social events of the Annual Meeting were the dinner- smoker on Monday night and the informal dance on Tuesday night, both of which were held at the Commodore Hotel. Approximately 400 attended the former event, compared with 570 a year ago, and about 250, people were attracted to the dance.

Jan 1, 1933

By Bruce Gellar

For the past six years, the author has made it a priority to attend the Prospectors and Developers Association of Canada’s (PDAC) annual conference. This most recent meeting took place March 10-13, 2002in Toronto, Ontario. In the three years since the author’s last PDAC report, the mining industry has undergone a severe trough. Some the industry’s woes included deeply discounted commodity prices, rampant layoffs, mergers, and overall avoidance by the investment community. However, at each of the PDAC conferences, the author has felt a heightened sense of excitement about the mining industry, more so than at other similar gatherings.

Jan 1, 2002

By James R. Arnold

Over the past few years several commercial wetting agents and drying aids have been tested in the lab and in the plant at Gold Fields Mining's operations at Mesquite and Ortiz. The major goal was to increase recovery with these surfactants by improving the permeability of the pad and increasing the rate of penetration through the rock.

Jan 1, 1988

By James E. Hill

Tremendous improvements in mining technology have been witnessed during the past 100 years. For example, before 1860 all blastholes were drilled manually and blasting was done with low-energy black-powder. During the 1860's both the pneumatic rock drill and high-energy dynamite were introduced, ushering in an era of mining mechanization that has steadily progressed since that time. Today, with the rapid implementation of the latest advances in communication science, mining technology is moving into a new era that goes beyond mechanization as such. Transistors, transducers, scanners, telemetry, and the like, all terms largely derived from the new communication sciences, add up to what is popularly know as automation-the communication of machine with machine. Automation is now playing an important role in selected parts of the mining process, such as hoisting, hydraulic roof supports, and underground surface locomotive haulage and belt conveyor systems. But this year marked the first attempt to auto-mate the total mining process with the commencement of production at the British National Coal Boards Bevercotes mine. If this full-scale experiment proves successful, it could lead towards other fully automated mines in both Britain and other parts of the world. This decade, there-fore, could be considered the one that provided the foundation for the mines of the future.

Jan 1, 1966

By W. A. Backofen, R. L. Fleischer

AN effect of orientation on the creep behavior of aluminum at 4.2 OK has been observed. Stress relaxation was measured in a hard-type tensile device after stopping the drive. From the spring constant of the device the load-time record could be converted to strain as a function of time. The strain sensitivity was 2-10-=, and the usual creep time of 1 min normally allowed a stress drop of about 25 g per sq mm. Further details of the apparatus and sample preparation appear elsewhere.' It should be noted that neither stress nor strain were constant, so that quantitative comparison with current creep theories will not be made. Shear strain (y) as a function of time (t) was consistent with logarithmic behavior: y = A In t, where A is a constant. In some cases t was made as large as lo3 sec. In the results the quantity A divided by t (the resolved shear stress, which is the driving force for creep) is plotted as a function of strain prior to creep. The quantity A/t is thought to indicate qualitatively the ease with which dislocations can move during creep. In Fig. 1 are drawn tensile stress-strain curves and A/T-strain measurements for single crystals of three orientations: l(a) and l(b) for the maximum resolved shear-stress orientation, l(c) for an orientation 2 deg from [211], and l(d) for a [111] stress axis. The following observations were made: 1) At low strains the A/t values are nearly the same for the three orientations. 2) As strains increase, A/t drops most rapidly for [Ill.] and less rapidly for [211], while for the maximum shear-stress orientation it is constant during easy glide and drops abruptly at the termination of easy glide. 3) In stage 11, A/t values are again approximately the same for the three orientations. These observations are regarded as evidence that 1) the initiation of slip produces obstacles of essentially the same effectiveness for all of these orientations, while 2) the rate at which slip obstacles are produced before stage I1 is fully developed is strongly controlled by the amount of slip on more than one system. This second statement is consis-

Jan 1, 1961

By Cyril W. Draffin

Introduction Americans have long been proud of their ability to recognize a need, define it, and then develop workable solutions. The U.S. underground coal conversion (UCC) program is a good example. In 1974, the need to utilize coal resources that could not be mined was recognized, and Congress gave the Bureau of Mines $1.7 million to gain a better understanding of the UCC technology and its potential applications. Since 1977 when the U.S. Dept. of Energy (DOE) was formed, workable technologies have been tested, the market for underground coal conversion has been recognized, and extensive industrial interest has developed. Perspective The U.S. is blessed with extensive coal resources. Coal supplies about 19% of our national energy needs, yet recently promulgated environmental standards and increasing mining costs have limited direct coal use. UCC potentially can use coal that is economically or technically infeasible to mine because the coal is too thick, deep, dirty, high-ash, and wet; has an excessive angle of dip; or has unpredictable and poor overburden characteristics that make mining unsafe. Coal can be gasified underground or perhaps liquefied below the earth’s surface. Underground coal gasification (UCG) is the prime element of the underground coal conversion program. It enables coal to be converted to gas underground. UCC Coal Resource Recent data show a total U.S. coal resource base of about 6.4 trillion tons. Of this, 1.8 trillion tons might be accessed by UCC, including some minable coal. A commercial UCC process could quadruple roughly the 450 billion tons of U.S. coal reserves, which presently are recoverable by mining. The U.S. coal resources are divided into five sectors. The two most eastern sectors contain relatively thin, swelling bituminous coals that are difficult to gasify. Of the two, the bituminous coal in the Eastern Province is the most difficult because it is deeper than , in the Interior Province and the terrain is more rugged. The sector along the Rocky Mountains contains huge amounts of thick low-rank coals that are the most promising for early development by UCC. The coal has good continuity and the terrain is suitable. Low-rank coals such as subbituminous and lignite are highly reactive and tend to shrink and disaggregate when heated. Most of the coal in the Pacific

Jan 1, 1980

By W. H. Morris

I have been requested to present a paper on the slag from the basic Bessemer process, as prepared for fertilizing. Since Professor W. B. Phillips presented at the Birmingham meeting, in May, 1888, an able paper* on this subject, as it had been developed up to that time, there is little for me to add. Perhaps later practice may be best expressed by the homely proverb, " The proof of the pudding is in the eating." As the Pottstown Iron Company is the only concern manufacturing basic Bessemer slag in this country, the writer's personal experience in the use of it may be interesting. Our slag averages: P2O5, 21.37; SiO2,, 5.10; MgO, 5.90; Al2O3, 4.01; MnO, 5.56 ; FeO, 12.00; Na2O and K2O, 0.80; CaO, 45.26; total, 100.00. This gives over 76 per cent. of phosphoric acid and lime. In using this material for several years past on my lawn and garden, I have found it better than anything else I have ever tried ; and I am sure that any of you who had seen my green grass last month (January), wherever the ground was bare from snow, as bright as in early fall, would be forced to acknowledge the advantages of this soil-enricher. The grass on my private lawn, and around the company's office, is green the whole winter; and we have raised very good sod, by the use of this phosphate, where, without it, we were unable to get the grass to grow either from seed or by repeatedly sodding. The same statement applies to garden-truck; when the soil was first broken up, a good crop of vegetables was easily raised. My own gardener has had several premiums from Philadelphia seedsmen (notably, last year, the first premium for sugarcorn raised in the first part of July, being the first sample sent them). Our method of applying this material is to grind the slag very finely, so that at least 60 per cent. of it will go through a 150-mesh screen (i.e., say, 22,500 meshes to the square inch), and 90 per cent. through a 100-mesh screen (i.e., 10,000 meshes to the square inch). This fine grinding seems to be the main condition of success.

Jan 1, 1893

FROM the first to the last meeting of t h e Rocky Mountain Club John Hays Hammond served as president. He guided its deliberations when there were any, but that always y o u n g organization was never particularly deliberate. Youth never is. And the Club was the embodiment of the youthful spirit of the West, which considers any- thing can be done if there be but the will to do it. Ham- mond and the others came out of the West, but they, brought the West with them P and in all the far countries in which he has served his profession and in all the honorable offices in which he has served his country, he lived true to the ideals under which he was raised. A Californian, born in San Francisco in 1855, the son of an army officer, Major Richard Pindell Hammond, educated in the public schools of his native city, at Yale, and at Freiburg, he turned early and quickly to mining. He served his apprenticeship as all successful mining men do, as assayer, surveyor, as assistant in ex-aminations and later as principal, and finally as mine manager. Even in those days of beginnings, his future world-wide career was foreshadowed in that Mexico as well as California served as his training school. His first major step up the ladder was in connection with the Bunker Hill and Sullivan mine, where he served in various positions finishing as president and considerable owner. It was from this great lead mine that he was called to South Africa, where he remained a number of years and was the technical expert who guided the great enterprises of Barnato Brothers and Cecil Rhodes. The story of his activity in developing the "deeps" of the Rand and in opening Rhodesia has been often told but is always an alluring one of adventure and accomplish-ment. After his famous escape from death at Johannes-burg as a member of the Reform Committee, he went first to London and later returned to the United States representing both British and American capital in the purchase and development of great mines in all parts of the world. For some years he was general man-ager, consulting engineer, and director of the Guggen-heim Exploration Co., but of recent years he has oper-ated entirely on his own account and with marked success.

Jan 4, 1928

By K. P. Anderko

INVESTIGATIONS of the constitution of the system Mg-Ba were first made by Grube and Dietrich1 between 0 and 47 atomic pct Ba and then by Klemm and Dincke1acker" ver the whole composition range. Klemm and Dinckelacker corroborated intermediate phases of the approximate formulas Mg9Ba and Mg4Ba, and showed a third compound to have the formula Mg2Ba, rather than Mg5Ba, as suggested by Grube and Dietrich. Mg2Ba had been previously recognized by Hellner and Laves3 s a MgZn2 (C14) type structure. The main discrepancies between the results of Grube and Dietrich and those of Klemm and Dinckelacker exist, however, in the liquidus temperatures and solidification equilibria of alloys containing more than about 10 atomic pct Ba. The liquidus temperatures measured by Grube and Dietrich, and the outline of the liquidus of Klemm and Dinckelacker are plotted in Fig. 1 on an enlarged scale. Although there are strong reasons to prefer the results of Klemm and Dinckelacker, it was considered worthwhile to remeasure liquidus temperatures of some alloys in the controversial composition range. The alloys, made up from sublimed magnesium and 99.5 wt pct pure barium, were melted in an Armco-iron crucible in a dynamic argon atmosphere. Thermal analyses were taken using a Speedomax auto- matic recorder. Careful stirring during the solidification process was required in order to avoid segregation. After thermal analysis some of the cast alloys were chemically analyzed. The intended and analyzed compositions of the ten alloys prepared are listed in Table I. Since standard barium determinations cannot differentiate between barium present as element and as oxide, both the barium and magnesium contents of the alloys were analyzed. The fact that the sum of barium and magnesium was close to 100 pct in each case was taken as evidence that no excessive oxidation had occurred. The liquidus temperatures measured are listed in Table I and plotted in Fig. 1. As can be seen, they are in good agreement with the liquidus found by Klemm and Dinckelacker. This leaves no doubt that the thermal results of Grube and Dietrich above 10 atomic pct Ba are incorrect. This work was performed under the sponsorship of the Pitman-Dunn Laboratories of Frankford Arsenal, Philadelphia, Contract No. DA-11-022-ORD-1975. Sponsorship and permission to publish by this organization are gratefully acknowledged.

Jan 1, 1958

By A R. Gerson

Pyrite, chalcopyrite and mixed sulfide samples, with and without quartz (5 wt per cent S), were subjected to column leaching to mimic natural weathering (cyclic wetting and drying). The pH and SO4 2- concentration of the column effluent was measured over a period of 78 weeks. The pH of the pyrite-only containing column rapidly decreased and remained under pH 4 after 12 weeks of leaching. The pH calculated assuming a 2:1 ratio of H + generation and SO4 2- release was slightly lower than that measured. However, a reduced H + to SO4 2- ratio of 1:1 is predicted if the release of aqueous Fe 2+ is assumed rather than the formation of Fe(OH)3. The pH of all columns containing only chalcopyrite or a 1:1 mole ratio of chalcopyrite and pyrite remained at or above pH 5 for the duration of the leach even though significant SO4 2- was released. One column containing the same initial surface area of pyrite and chalcopyrite but only approximately 0.10 the mole fraction of S as chalcopyrite maintained a pH of greater than five for the first 56 weeks of leaching and showed sporadic acid production thereafter. It is well established that oxidation of chalcopyrite results in a surface layer of polysulfide material. It is the formation of polysulfide that neutralises the acid produced on S oxidation through to SO4 2-. Hence where polysulfide formation occurs extensively on chalcopyrite the resulting solution pH decrease will be less than that based on SO4 2- production. The oxidation rate of sulfide minerals increases with decreasing pH and hence acid formation via sulfide oxidation to SO4 2- causes the subsequent oxidation rate to increase. The addition of calcite (CaCO3)to a pyrite column not only neutralises the acid formed but also decreases the rate of release of sulfate to solution by a factor of approximately 30. This is also the case where chalcopyrite is present mixed with pyrite. The rate of release of sulfate from the mixed sulfide mineral columns (after the initial release of the sulfate already present) was between one-fifth and one-tenth that in the absence of chalcopyrite.

Jan 1, 2003

By T. C. Clarke

The history of iron construction in this country well illustrates the three phases of thought described by Auguste Comte, the French philosopher. The first is the era of faith, when belief in the safety of structures rests on the authority of the designer. The second is the era of criticism, when plans of structures are analyzed with much mathematical skill, but the data upon which the chain of reasoning depends is assumed upon insufficient experiment. The third, upon which we are now entering, is a scientific era, which demands experimental proof. It also demands that this proof shall be derived from experiments made on full-sized specimens, such as are in actual use, and not upon toy models. Until the construction of the United States testing-machine, now at Watertown Arsenal, it was impossible to make such experiments with accuracy. We now have a machine in which we can test full-sized specimens of every part of a bridge or other structure that we want to use, and under the same conditions in which it is actually used. The next thing is to get money to make these experiments available. No private individuals can afford to do it, and even if they could, they might wish to keep the results to themselves. So that the next point is that we want money, and that, I believe, everybodly thinks we should ask Congress for. We want also, as has been said, some one who shall make a business of testing, and who has plenty of time. Persons who are employed in private business are too much in a hurry; they want to do a thing and get done with it, and then do something else; but government officers are entirely free from this feeling; time to them is of no account, and in experimenting that is the very element that is of value; it does not do to be hurried; the great thing is to get it right and to test your results, and go over it, again and again. And the experimenter who operates the machine must be some person educated up to the use of it. We then want a general advisory board who will indicate a plan of experiments, collect the results; and publish them. Some experiments were made the other day at the Watertown Arsenal upon full-sized

Jan 1, 1882

The society in which we live is one of change, and we professionals are part of that society. The importance of this simple and obvious statement is often overlooked. My Presidential Address examines the question: can professionalism survive in our changing society?There is ample evidence to show that our society is changing, and that the rate of change is exponential. This rapid and accelerating rate of change is what Alvin Tomer refers to as "future shock". Rapid change means that we do not have time to become accustomed to what is happening around us and to feel comfortable with it; the greater the rate of change the greater the discomfort. The effect that this has on people is varied; the change may be either expected or totally unexpected.The rate and extent of change in society is not the same for all countries nor for all industries or occupations. Change is more rapid in Japan, Korea or Taiwan, than in Australia. It is more rapid in our cities than in the bush, more rapid for professional businessmen than for farmers. In our minerals and petroleum industries, we are still adjusting to the great changes that have taken place over the last fifteen years. In the past, products from our industries were sold on a free and open market. Today, mineral development and production in most undeveloped countries and some developed countries is manipulated for political, social and economic reasons. Changes of this nature have had a devastating effect on the operations of established mineral producers in the democracies.Because of the accelerating nature of change, we must recognise that the past is not a reliable guide to the future.Although extrapolation of the past into the future is a basic ingredient of commercial survival, extrapolation is less and less reliable.I borrow from others in quoting the Irish proverb: "The future is not what it was".The future is where our business lies and most of us at this Conference must endeavour to understand it and adjust to it. I believe in the old adage that:You can't know where you're going if you don't know where you've been and where you are at.There are a number of major factors which have created change within our social, economic, and industrial environment in recent years.

Jan 1, 1985

By Frank Hagar, George M. L. Robinson

NTRODUCTION The Resource Conservation and Recovery Act and CERCLA (SUPERFUND), in many instances, has had an adverse economic impact on the hardrock mining industry. Over the last few years, many abandoned and active mining operations have been added to the Environmental Protection Agency (EPA) National Priority List (NPL) . When the property is placed on the NPL the operator or EPA is required to conduct extensive environmental assessments to determine if historical mining practices have degraded the existing environmental. If degradation has or will continue, the responsible party is required to implement appropriate remedial action plans. If a responsible party is not identified, the EPA implements a cleanup program. Experience has demonstrated abandoned and active mining operations are subject to RCRA, and possibly Super- fund, if the mine has not adopted appropriate hazardous waste disposal management procedures. If off-site contamination has occurred, the operator will be required to mitigate the impacts and will be required to adopt additional procedures to minimize future impacts. Since the passage of RCRA and Super- fund, many mining operators are adopting management procedures to monitor and inventory hazardous sub- stances and wastes generated, stored and disposed on site. Many operators are in a difficult position because ore, waste rock, process chemicals or other solid waste, in many instances, can be classified as hazardous waste. If the process or other solid waste is deemed to have the characteristics of a hazardous waste, the operator can inventory and adopt appropriate, in- expensive management procedures. However, if the ore or waste rock has hazardous waste characteristics, in- expensive control technologies are impossible to implement. Since existing statutes and regulations require hazardous waste control, the operator will be required to inventory, characterize and monitor all aspects of the mining operations including but not limited to exploration, mining, ore processing and waste disposal. During this process, geological, geotechnical, geochemical, waste and ore volumes, and process materials must be tracked throughout the mining process. To accomplish this task, the most cost effective method to maintain documented and accurate records, is through the implementation of an integrated database management system. The database management system can be used to model and simulate the entire mining operation and if necessary, used to predict whether the operation is in compliance with existing regulations. The developed database can also be used to operating optimize mining and disposal costs.

Jan 1, 1987

By Scott D. Long

"Abstract-Grass roots exploration has an emphasis on good precision at low (sub-economic) concentrations of an element, in order to identify "anomalies" which may lead to drilling targets. Although it is wise to have well-defined quality controls in place during early stage sampling, the control procedures at this stage tend to be rudimentary. When a deposit warrants detailed delineation, the need for accurate geological characterization and assaying of ore-grade rock must be supported by appropriate quality control procedures.As a project returns more promising results, and the likelihood of the project warranting a prefeasibility study increases, it is time to tighten quality assurance requirements and quality control protocols. Delays in instituting adequate quality control and verification procedures may lead to costly remedial actions that can also delay completion of the prefeasibility or feasibility study. Sometimes, as a project matures, the quality control and quality assurance aspects fail to keep pace with the changing nature of the work: an increasing emphasis on precise and accurate assaying of oregrade rock.A resource model is like a house of cards. The foundation of the house is the geological observations, the sampling methods and the geological interpretations performed upon those samples. Upon the sampling, which includes all the sub-sampling steps of sample preparation, rest the assay results. The quality of the assays can be no better than the quality of the sampling. Good assaying technique will preserve all biases and imprecisions introduced during sampling and sample preparation; it cannot remove them. If the sub-samples and/or assays are bad and must be redone, all the succeeding levels of the house of cards must also be rebuilt, or at least patched up.From geological observations, a geological interpretation is built, the quality of which is critical to the construction of an acceptable resource model. Geological elements are difficult to assess, and are not discussed here; they are dependent upon the expertise of the geologists involved. Geological knowledge contributes essential quality control elements to resource/reserve determinations (Sinclair and Postolski, 1999; Postolski and Sinclair, 1999).This paper consists of five sections: (1) overview of quality control protocols, (2) maintaining quality control of databases, (3) quality control of drill sampling, (4) optimizing crushing and grinding requirements, and (5) quality control of assay data acquisition."

Jan 1, 1998

By Cyril W. Draffin

Introduction Americans have long been proud of their ability to recognize a need, define it, and then develop workable solutions. The U.S. underground coal conversion (UCC) program is a good example. In 1974, the need to utilize coal resources that could not be mined was recognized, and Congress gave the Bureau of Mines $1.7 million to gain a better understanding of the UCC technology and its potential applications. Since 1977 when the U.S. Dept. of Energy (DOE) was formed, workable technologies have been tested, the market for underground coal conversion has been recognized, and extensive industrial interest has developed. Perspective The U.S. is blessed with extensive coal resources. Coal supplies about 19% of our national energy needs, yet recently promulgated environmental standards and increasing mining costs have limited direct coal use. UCC potentially can use coal that is economically or technically infeasible to mine because the coal is too thick, deep, dirty, high-ash, and wet; has an excessive angle of dip; or has unpredictable and poor over-burden characteristics that make mining unsafe. Coal can be gasified underground or perhaps liquefied below the earth's surface. Underground coal gasification (UCG) is the prime element of the underground coal conversion program. It enables coal to be converted to gas underground. UCC Coal Resource Recent data show a total U.S. coal resource base of about 6.4 trillion tons. Of this, 1.8 trillion tons might be accessed by UCC, including some minable coal. A commercial UCC process could quadruple roughly the 450 billion tons of U.S. coal reserves, which presently are recoverable by mining. The U.S. coal resources are divided into five sectors. The two most eastern sectors contain relatively thin, swelling bituminous coals that are difficult to gasify. Of the two, the bituminous coal in the Eastern Province is the most difficult because it is deeper than in the Interior Province and the terrain is more rugged. The sector along the Rocky Mountains contains huge amounts of thick low-rank coals that are the most promising for early development by UCC. The coal has good continuity and the terrain is suitable. Low-rank coals such as subbituminous and lignite are highly reactive and tend to shrink and disaggregate when heated. Most of the coal in the Pacific

Jan 9, 1980