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By M. A. Evanto

Since the late 1970's, the Roof Control Division (RCD) of MSHA's Technical Support has been performing linear analyses for the enhancement of miners' safety. This remote sensing process uses Landsat data to predict areas of potentially hazardous ground conditions in underground mines. To date approximately 700 analyses have been completed by the RCD, with nearly 75 being performed with the current equipment, software and methodology which was updated in early 1995. While success is difficult to measure, requests for linear analyses continue to come from large and small mining companies which suggests the industry's acceptance of the process.

Jan 1, 1998

By Arnold E. Lamm

The degree of economic, progress of a nation is measured by its possession and use of energy, sources. The future of coal in the West hinges on its ability to participate and grow in the energy market. A source of energy is, in the long run, only as good as the ability of the industry to develop its reserves economically. The economic development of the tremendous coal reserves, literally hundreds of billions of tons of coal in the States of Colorado, Utah, Wyoming, Montana, New Mexico, and Arizona, poses a very real question in the light of the known mining technology of our day. Basically in America today, coal is mined from the earth either by the strip mine or underground mine method; in the West, the large long-term, contracts now in force with utilities are mostly from coal mines utilizing the strip mine method. However, the preponderance of the known coal reserves of the West are located deep underground and will have to be mined by the various; underground mining processes. The problems encountered in the West with regard to underground mining vary from state to state but, on the whole, do not present what might be considered a miner's bonanza. I do not mean to' infer that the underground coal of the West is unmineable, but I do want to emphasize that the tremendous reserve figures do not present a true picture in the light of present day technology.

Jan 1, 1965

By X. M. Zhou, T. Wu, He X. N.

"In order to study the support effect of concrete in the surrounding rock of a metal mine, the concrete and surrounding rock were comparatively studied. Firstly, the general situation of the ultra-kilometer deep shaft in Xincheng, surrounding rock and geological conditions are introduced. Secondly, the experimental scheme of material mechanical properties of surrounding rock and shaft lining concrete based on same standard dimension and shape are examined, and the mechanical tests of rock and concrete based on different shapes and sizes are carried out. The study shows that the compressive strength value and elastic modulus of the rock cube are 1.28 times and 1.78 times that of the cylinder, and the Poisson's ratio is 0.77 times. The dimensional effect law of the concrete cube and cylinder test data is consistent with the rock law. However, the test results of the concrete are less discrete than the rock; the test also shows that the strength and elastic modulus of the concrete lining of the main shaft of the Xincheng are much smaller than the surrounding rock that is also used as the concrete aggregate, which indicates that the support of concrete lining in the surrounding rock shaft behaved weakly. Based on the development of the modern NATM rock support theory, it is suggested that the mechanical test standard of artificial support materials should be unified into the mechanics test standard of natural rock, which will help to improve the accuracy and practicality of scientific calculation of geotechnical engineering.INTRODUCTIONConcrete and rock mass are usually attributed to a class of materials called frictional materials or geotechnical materials, of these two kinds of materials, the first is man-maded and the second is natural. The attentive scholar can find that there are many differences in the test criteria for the mechanical properties of the two kinds of materials among different industries or departments, reflecting the differences in their sources, tradition, and the application thoery of material strength among them.There is a situation wordwide, that there are many testing standards of the same material mechanical parameters such as elastic modulus, compressive strength, etc. The cube with a side length of 150 mm is adopted as a common sample in the architecture department in China, while a cylinder with a diameter of 50 mm and a height of 100 mm is as a standard specimen in geotechnical department.Knowing that mechanical parameter values are strongly affected by the the size, shape of specimen and loading rate etc, that is to say the mechanical parameter values of the same material are completely different when obtained from different test with different standards. However, such a problem has been long neglected in geotechnical engineering."

Jan 1, 2019

By R. A. Matuszak

Abstract-Throughout the history of power excavating machines, engineers have continuously tried to shape the main drive speed-torque characteristics to provide an optimum performance from each main motion. Selection of prime mover for the various motions has been the subject of many engineering studies and most forms of energy conversion have been tried. A new form of electrical power conversion looms on the horizon as the most optimum yet. Controlled frequency operation of a squirrel cage induction motor increases the reliability of the most reliable form of energy conversion (electrical) found thus far, and improves the performance characteristics.

Jan 2, 1978

By T. D. MacQueen

Thank you Mr. Stevens. It's a pleasure for me to be speaking to this meeting of the Society of Mining Engineers of AIME this afternoon, and the Gypsum, Association is grateful for the invitation. A brief word about who we are: the Gypsum Association is the trade association for the gypsum industry - the manufacturers of gypsum board and lath a-d plaster. We have a membership of eight companies. These eight companies produce about 90% of the gypsum products manufactured in the United States ... closer to 94% actually. Our headquarters is in Evanston, Illinois. We have an east coast office in Washington, D.C. where the eastern manager handles technical and building code matters and maintains liaison between all of the government agencies and departments and our industry. We also have a west coast office in Los Angeles where our west coast representatives is heavily involved with the Uniform Building Code and ICBO. And then in the Evanston office our manager of technical and building code services, Herb Carlsen, bites his nails and loses his hair over these problems and various other projects that come in, such as conversion to metric and various other things. We also have a research associate at the National Bureau of Standards in Washington who is currently concentrating his efforts on the combustibility of building materials. His studies involve current testing methods, definitions, data analysis, and proposed new testing methods,.' It is anticipated that this program will lead to a better understanding of non-combustibility of building materials and systems. I mentioned that our members represent over 90% of gypsum products,' manufactured in the United States; it might be well to point out a couple of statistics about what that really means. According to the Bureau of Mines,

Jan 1, 1977

By J. P. Gouvea, T. R. Stacey

A research project was carried out on a gold mine in the Vaal River region of South Africa (Witwatersrand Basin) to evaluate the effect of two particular aspects of rockbolt installation – the angle of inclination of the bolt relative to the orientation of the rock surface, and the protruding length of the bolt – on the mine’s gully support system. A keyblock analysis approach indicated that these factors do not have an adverse impact on the stability of the strike gullies. This was confirmed by extensive empirical data collected from the case study mine. While safety is the primary concern, cost saving opportunities can be realized through reconsidering historically inherited support standards that are perceived to be correct and appropriate. The research described in this paper sets forth a practical approach, that is easy to implement and repeatable, to evaluate the role of rockbolts in stoping gullies.

Feb 12, 2024

By E. Viljamaa

In this research, earlier developed information integration method and novel web technologies are applied to intensify infrastructure construction process control. The applied method uses semantic methods to integrate scattered information that is later on exploited by process management using state-of-the-art web technologies. The applied method and web technologies not only improve the process management situation awareness by integrated up-todate multi-source process data but also provide platform independent access and visualization tool for process data. Utilization of such technologies potentially lead on cost savings, make processes safer and also more environmentally friendly. The integration method also enables intelligent queries to the integrated data making possible to use machine based inferring to the data.

Aug 1, 2013

By George S. Rice

Potash is riot only an important ingredient in the manufacture of many products of modern industry, such as chemicals, explosives, medicines, paints, soap, matches, glass, paper, aniline dyes, bleaching agents, and a host of others, but is indispensable in agriculture. Justus von Liebig is credited with being the first to discover, about 1858, that potash salts in the soil constitute an essential plant food which is not replaced by nature when exhausted through continued cultivation, that this exhaustion results in a decreasing yield of crops, and that the virgin productivity of the soil may be restored, and indeed even increased, by the addition of suitable potash fertilizers. The fact is now well established that wherever intensive cultivation is employed, whether for the raising of cereals, cotton, tobacco, fruit, or garden truck, the replenishment of the potash content of the soil is essential to the maintenance of production. Hence potash is of primary importance in modern life, not only for the economic welfare of industry but for the production of valuable raw materials and the very food supply of the nation itself. SOURCES OF POTASH The main sources of commercial potash are: (1) The solid deposits of soluble potash minerals, such as carnallite, sylvinite, and kainite; (2) sea water, brines, and salt-lake deposits containing appreciable amounts of potash salts associated with sodium salts; (3) vegetable substances, such as wood ashes, bee sugar residues, seaweed, and sunflower stalks; (4) animal material, such as wool washings; (5) products resulting from the decay of organic nitrogenous matter, such as Indian niter; (6) dust in flue gases from cement kilns or in the top gases of iron blast furnaces; and (7) insoluble potash minerals, including alunite, feldspar, leucite, muscovite, and glauconite, all of which contain a considerable quantity of potash.1

Jan 1, 1927

By B. M. O'Harra

Zinc smelting is frequently termed a ba.ckward art. The term is hardly true, for great progress has been made in recent years in the design and in the thermal efficiency of the retort furnace, in the quality of retorts, in the recovery of zinc, and in the ability to treat more impure and complex ores. The fact remains, however, that the peculiar physical and chemical properties of zinc have delayed such immense advances-large smelting units, high recovery, lowunit costs, and ability to treat low-grade ores-as have been made in the metallurgy of lead and copper. In current retort-smelting practice, the ores, if carbonates, are calcined to remove carbon dioxide; or, if sulphides, are roasted to remove sulphur. The sulphur must be eliminated as completely as possible, usually to less than 1 per cent. This means that the roast must be continued for a long time at a high temperature, with resulting high cost and small capacity per furnace. The roasted ore is mixed with about 50 per cent of its weight of reducer, which may be fine coke, anthracite, or nonbituminous coal. This mixture is charged into horizontal fire-clay retorts. The retorts used in this country are about 8 inches in internal diameter by 4 feet in length and hold 50 or 60 pou~ds of ore. The diameter of the retort is limited by the tirrie required for the heat to penetrate to the center of the charge; the length by the strength of the retort, which at the high temperature employed can not support the weight of the charge if the span is more than about 50 inches. The retorts are heated externally by coal, natural gas, qr ·producer gas to a temperature of 1,200° C. or more. The zinc oxide is reduced to zinc, which is volatile at this temperature, and passes into a conical fire-clay condenser. attached to one end of the retort, where it conde_nses to liquid zinc and is removed. Twenty-four hours are required for distillation, and because of the low heat conductivity of the retort walls 11.nd of the ore charge itself, the heat efficiency even of the most modern regenerative furnacei;; is only about 12 per cent. The retorts have a short life, 30 to 6Q days, at the high temperature required-; zinc losses are heavy, usually 10 per cent or more; and the proportion of impurities in the retort charge must be carefully controlled to prevent the rapid corrosion of retorts. For these reasons, much work has been done in an e:ff ort to, find cheaper and more efficient methods o.f recovering zinc from its ores. Various methods have been proposed for smelting in the blast furnace. Some of these contemplated the production of zinc vapor and its condensation to liquid; others attempted to produce liquid zinc directly by smelting under pressure. It is now realized that fundamental difficulties render these proposals impracticable. The electric furnace for smelting offers obvious advantages in the way of the efficient utilization of energy, large units, easy attainment of high temperatures, and the possibility of treating complex ores. E. H. and A. H. Cowles first suggested a design for an electric furnace for the reduction of zinc ores and patented their process in 1885. Their attention was soon directed to other uses for their furnace and nothing further of importance was done in the electric smelting of zinc until about 1900. Several investigators then started work upon various processes and had more or less success. The chief difficulty they encountered was the impossibility of obtaining more, than a small amount of the zinc as liquid metal because most of the zinc vapor condensed as blue powder. Interest in the electrothermic metallurgy of zinc increased, many patents on processes and furnace design were taken out, and the literature on the subject grew, until in 1914 and 1915 the problem seemed to be approaching solution. About this time the hydrometallurgy of zinc, the development of which had been lagging somewhat behind that of the electrothermic metallurgy, sprang into the limelight and a commercial process was soon perfected. This rapid development, perhaps aided by the war premium on the high-grade spelter produced by electrolytic deposition, distracted attention from electric smelting to some extent, though progress continued. With the perfection and standardization of the electrolytic process has come a better realization of its limitations, especially the necessity for large-scale operation ·and the difficulty of obtaining high extraction. Because of these limitations the electrothermic metallurgy of zinc still has a field of its own and in fac-t promises to become a strong competitor of both hydrometallurgy and retort smelting except under conditions highly favorable to the latter methods. Because of the imperfections of the retort and electrolytic processes and the promise that the electric furnace offers in overcoming these imperfections, the. United States Bureau of Mines, in cooperation with the Missouri School of Mines and Metallurgy, has undertaken a study of the electrothermic metallurgy of zinc.

Jan 1, 1923

By Nicholas Kyriazi

A joint effort by the U.S. Bureau of Mines and the U.S. Mine Safety and Health Administration (MSHA) was undertaken to determine how well self-contained self-rescuers (SCSR's), deployed in accordance with Federal regulations (30 CFR 75.1714), survived the underground environment with regard to both impact damage and aging. This report presents findings regarding laboratory-tested SCSR's from 1982 through 1990. The SCSR's were tested on human subjects and on a breathing and metabolic simulator (BMS). These results indicate that most of the apparatus, if they pass their inspection criteria, perform as expected except for units with manufacturing defects or design deficiencies. However, when the apparatus are carried in and out of the mine daily and stored at the working section, they may suffer abuse. Physical signs of abuse, unless extremely obvious, are frequently not detected by the miners or mine operators. This poses a potential danger to a user in an emergency. Recommendations include improved training in inspection procedures.

Jan 1, 2010

By James Paone

This report shows the feasibility of predicting drillability, analytically, by using regression analysis techniques. The approach is new in diamond-drilling research. Further, the study shows that this technique may be of value to drill manufacturers and others in mathematically delineating performance characteristics of new drills in specific rock types. Another application might be the prediction of penetration speeds in extraterrestrial material based on the physical properties of the materials as samples become available. Prediction equations for penetration rates are presented for 9 rocks drilled in the laboratory and for 20 rocks drilled under field conditions. The prediction equations are based on drill operating parameters and on characteristics of the rock penetrated. No single physical property appeared consistently in the best predictor equations, and all the physical properties were found to be highly correlated with each other.

Jan 1, 1966

By Joseph H. White, DR. JAMES G. CUMMING

This report presents the results of an investigation of hookworm infection in the deep gold mines of the Mother Lode, California. In this investigation 1,440 miners of the Mother Lode have been examined for hookworm infection; 444 miners were found to be infected; and 91 miners have taken the treatment and have gotten rid of the infection. ·Within a short time after this preliminary examination, an industrial strike started, which gradually scattered the miners and made it difficult to institute the treatment of many of those who had been found infected. ·With the completion, however, of the State survey all these will eventually be identified and treated. In 1906 Dr. F. F. Sprague, of Jackson, Cal., and formerly of the Philippine Islands, recognized the prevalence of hookworm infection in the gold mines of California. He treated many cases of the infection and brought the prevalence of the disease to the attention of his colleagues. Following closely this pioneer work of Dr. Sprague was that of Dr. E. E. Endicott, health officer of Amador County. In 1911 Dr. Endicott a related his experience in a paper before the American Medical Association. In 1909, Dr. Herbert Gunn, under the auspices of the California State Board of Health, made an investigation to determine the prevalence of the disease among miners. b He reported on the blood and stool examinations of groups of men from three large mines in Amador County. The high eosmophilia verified by stool examinations in many of the cases, and the demonstration of larvae in soil from the workings led Dr. Gunn to the following conclusions: 1. Hookworm disease is endemic in certain mines of California. 2. From 50 to 80 per cent of those working in these mines are infected. 3. The infection undoubtedly is present in practically all the gold mines of California and in those of Nevada just over the border. vYhen it was definitely determined by the California State Board of Health to make an investigation, in cooperation with the Industrial Accident Commission of the State of California and the Federal Bureau of Mines, as to the prevalence of hookworm infection among the miners of California, the following procedure was planned: (1) To encourage the superintendents of the various mines to cooperate in the campaign; (2) to diagnose fecal specimens from the miners and determine the percentage of infected miners; (3) to reach an agreement with the superintendents that all infected men must be treated; (4) to make reexaminations of all treated men; (5) to issue "hookworm certificates"; and (6) to eventually reexamine all California miners. A visit to several of the mines on the Mother Lode made it evident that the mine operators would cooperate most cordially in this campaign; in fact, several superintendents had already considered the advisability of such an undertaking.

Jan 1, 1917

By Hector O. Romero, Paulo C. Fernández A, Christian Rees Prado, Claudio C. Gajardo

In open-pit mining operations, the presence of remnants from past underground labors represents a significant operational challenge, especially if they are in the surroundings of high-grade zones. The existence of uncrushable elements, such as metallic support fragments of abandoned equipment, can trigger critical operational issues if they reach conveyor belts systems or primary crushers, jeopardizing the mine to plant operational continuity. These kinds of incidents lead to expensive unplanned shutdowns, the increasing of corrective maintenance events costs, and risk to meeting expected production results. This work demonstrates the application of a three-dimensional numerical modeling tool for simulating rock displacement post-blasting (by integrating key design parameters, such as blast pattern design, detonating times, charge distribution and pre and post blast surveying). The study was conducted at Andina Mine, operated by Codelco, Chile, and enabled the identification and zoning of areas with potential presence of underground hazards in displaced rock mass, using historical data from previous workings and geotechnical mapping. The displacement results were compared to the actual post-blast surveying, ensuring an acceptability level above 80%, considering both fully confined (bank opening) and free-face blasts. Additionally, this approach allows the determination of an optimal safety offset, initially set at 10 meters and currently under validation for potential reduction. The results supported the determination of safe extraction zones and the design of excavation, loading, and haulage strategies from mine to plant or stockpile, ensuring 100% reliability in the segregation of high risk materials. Implementing displacement simulations underscores their relevance in operational risk prevention and mitigation, adding value to short-term mine planning and strengthening the safety, efficiency and profitability of the open-pit mining production process.

Jan 26, 2026

By S H. Begg

There is strong evidence that many major oil and gas (O&G) projects are plagued by large cost and schedule overruns, or significant underperformance in productivity. Similar evidence exists for large mining projects. This paper claims that uncertainty is the underlying reason why projects fail to deliver the metrics used to justify their investment, or to deliver the economic value possible if alternative decisions had been made.Most technical and economic analyses are performed to reduce uncertainty to help make decisions. Decision-making is about ranking alternatives and choosing the best; rarely are precise predictions required, if this is even possible. Better uncertainty assessment is one of the keys to better decisions, thus better business outcomes. To get better decisions it is suggested that the focus or reward/penalty incentives be shifted away from the quality of outcomes to the quality of decisions. High-quality decisions are those that are generated from the skilled use of the tools, methodologies and processes from the discipline of decision analysis.Uncertainty is quantified by probability, which is a degree of belief in the truth/falsity of some proposition about a quantity relevant to a decision, such as volume of in-place resource, future price or action of a competitor. The probability a person ascribes to a proposition depends upon their information set; hence probability is subjective – it is not an inherent attribute of the quantity of interest or the physical system.The above simple observations have profound implications for modelling approaches, how they deal with uncertainty, the use of data to help assess uncertainty and the reliability of information provided by subject-matter experts. The limited circumstances under which frequency data (from spatial or temporal variables) can be used to assign probabilities is also reviewed.People, in general, are subject to a range of biases and cognitive errors. Research with O&G subject-matter experts shows that their expertise offers little or no protection from making errors in probability assessments and other judgements.CITATION:Begg, S H, 2016. Decisions, decisions – uncertainty, variability, modelling and psychology, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 9–18 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

To expediate the transfer of technology from Bureau laboratories into new products and processes that enhance the economic competitiveness of the U.S. mining and minerals industry in world markets. Background The U.S. Bureau of Mines and various members of the industry are concerned about the current technology challenge to the minerals industry in the United States. They arc working together to delineate ways of enhancing the mineral industry's technology base. More emphasis is being placed on collaboration between the government, academia, and industry to formulate the innovative revolutions needed to maintain our technology edge. Through these partnerships, real issues and problems can be identified, the industry's needs as customers can be defined, and research and development activities can be tailored to meet these needs. Now is an especially exciting time in research because some special opportunities exist to encourage private industry to capitalize on Federal laboratory research and development. These opportunities arc called CRADA's. What Is A CRADA? The Congress recently enacted a mechanism that enhances collaboration between industry and government through the Technology Transfer Act of 1986. A key lea lure of this Act is a provision through which Cooperative Research and Development Agreements or CRADA's can be developed to encourage industry and government to work together and stretch their research budgets. By entering into a CRADA, a private, non-Federal company can cost-effectively perform research by sharing the costs of this research with the Federal Government. The agree¬ment involves no transfer of funds from the Government. The Government agrees to provide personnel, services, facilities, equipment or other resources (but nut funds) and the non-Federal party agrees to provide funds, personnel, services, facilities, equipment, or other resources needed to conduct a specific research or development effort.

Jan 1, 1992

By S. K. Chaurasiya

o meet the ever increasing demand of iron oxide feed stock for rapidly growing domestic steel industries and to effectively manage the depleting reserve of high grade lumpy iron ore, Pelletization of iron ore fines/slimes are expected to play a dominant role in the near future. Use of pellets will also enable the blast furnace operator to achieve higher levels of productivity with lowering of operating cost. The effective utilization of Iron Ore Slimes is important not only from the point of view of optimum utilization of Iron values in the mined ore but also for preventing environmental pollution. A significant amount of slime is being accumulated at the tailing dam of one of the iron ore mines and with the present scale of operation the tailing dam will be filled in another 10 years. Hence to increase the life of tailing dam and for better utilization of the iron values a study has been carried out for the suitability of pellet manufacturing with slimes and fines at our laboratory. The pelletization studies are aimed for optimization of various parameters for production of Blast furnace/ DR grade pellets from beneficiated slimes and Fines. This paper attempts to describe the production of blast furnace grade pellets from beneficiated slime and fines and its characterizations.

Sep 1, 2012

By Thomas T., Read

SUGGESTIONS that existing schools give instruction bearing on the mineral industry, or that schools for that purpose should be established in the United States, began to be made early, and it would require too much space to catalogue them all. Some of the more important may be mentioned to indicate their general character. In the "advertisement to such parents as have now (or expect to have) children prepared to be educated in the College of New York," which appeared in the New York Mercury of June 3, 1754, Samuel Johnson, the first president of King's College, the predecessor of Columbia, said that it was the "design of this college to instruct and perfect the youth," among other things, "in the arts of Numbering and Measuring of Surveying, and Navigation and Geography. . . . and in the Air, Water and Earth around us, and, the various kinds of Meteors, Stones, Mines and Minerals, Plants and Animals; and in the knowledge of all Nature in the Heavens above us, and of everything useful for the Comfort, Convenience and the Elegance of Life . . . " Though the concept that natural science should be used to enlarge the bounds of human life was thus implicit at Columbia from the very beginning (John Stevens graduated from it in 1768, James Renwick in 1807, Horatio Allen in 1823, and A. W. Craven in 1829), it was only during the period of Renwick's professorship of Natural and Experimental Philosophy and Chemistry (1820- 1853) that much attention was given to applied science.* Among the Austin papers, published by the American Historical Association,2 there is a draft in Stephen F. Austin's handwriting of a proposed memorial from the legislature of Missouri to Congress, not only urging "the propriety and utility

Jan 1, 1941

By Howard E. Banta

From Alaska to Florida and California to Maine, the National Forest System (NFS) is host to unprecedented levels of prospecting and development. The NFS is large (191 million acres), geologically attractive from the mineral standpoint and relatively unexplored. Significant recent finds and developments involve silver, gold, platinum group metals, molybdenum, cobalt and phosphates. Exploration and development are closely regulated, but most of the NFS is open. The Forest Service endeavors to be a good host to the mineral industry, but increasingly is asked or forced to delay or disapprove mineral projects to protect the environment.

Jan 1, 1984

By G. W. Adams

Foreword While the literature on radium is voluminous, there is no single publication available from Canadian sources which attempts to cover at all fully the world radium industry. The comparatively recent developments in the Wilberforce area, and the consequent arousal of public interest in radium, seemed to call for the publication of such a paper which would be intelligible to the layman. To satisfy this apparent need, the writers submit this paper which contains material derived from various sources, and for which the writers make no claim of originality. Direct references are made throughout the paper to sources of information.

Jan 1, 1931

After more than 20 years dependence on bituminous coal as a primary fuel for generating electricity, the Pennsylvania Power and Light Company initiated a one-year study on the economics of building an electric generating station using anthracite as a fuel. The study will be completed in December 1976. If the feasibility study so indicates, PP&L will consider installing four 400,000 kilowatt generating units for scheduled commercial operation in 1985. Each unit would consume up to one million tons of anthracite annually. Anthracite generally is more difficult and expensive to extract than bituminous coal, but it has a significantly lower sulfur content than the bituminous coal currently being used by PP&L, thereby eliminating the costs of installing sulfur emission controls at generating stations. Moreover, significant reductions in transportation costs may be realized because the utility's operating territory is situated in the center of the anthracite region in northeastern Pennsylvania. These advantages may indicate that the use of anthracite is more economical than bituminous coal to PP&L. ASBESTOS -Asbestos production in the U.S. dropped again in 1975 until it was just two-thirds of that in 1973. This was in spite of the very strong demand caused by the Quebec strike. The 7-month strike of the asbestos miners in Thetford Mines, Quebec cut off 55 percent of the normal supply of U.S. consumers. Apparent domestic consumption was less than 75 percent of that in 1974. The wage settlement will probably result in a 20 percent increase in asbestos prices.

Jan 1, 1975