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By Ralph Sherman

IN these days of intense competition for the domestic fuel market much is heard of the low efficiencies with which solid fuels, and most particularly bituminous coal, are burned in domestic heating equipment. In contrast to the every-day operating efficiencies of 85 and 90 per cent in large, central, electric-generating stations, efficiencies of 50 per cent and lower are cited for the hand-fired home furnace. Just as the miles per gallon of gasoline is only one of the factors that determine the cost of operation of an automobile, so the thermal efficiency is only one factor in the cost of domestic or other heating. The purpose of this paper is to analyze the total costs of domestic heating by various fuels and types of equipment, to determine the relative importance of efficiency and other factors, and to discuss what this signifies relative to the future of the use of fuels in the home.

Jan 1, 1933

By R. L. Loofbourow

The objectives of this report are (1) to indicate what is known of natural rock temperatures as deep as 5000 ft below the surface, (2) to indicate methods for estimating such temperatures in localities where directly measured temperatures are un- available, and (3) to outline as far as possible, areas in the 48 states within which rock temperatures are likely to be low and high. The usual object of temperature measurements in deep mines and wells is to learn the temperature of air or another circulating medium. This usually differs significantly from the undisturbed rock temperature. The subject is complicated further by the variety of the thermal properties and structures of rock masses, the migration of fluids within them, the diversity of the history of rock masses and of the processes which have been at work on them during that history.

Jan 1, 1966

By O. Bergmann, R. E. Lueders, R. R. Ellefson, H. M. Brennecke, D. S. Davies

A new hydrometallurgical process has been developed to recover copper from sulfide ores. Copper is leached in a staged reactor system utilizing nitric and sulfuric acids at 105OC. Iron is removed from the pregnant liquor as a jarosite, and cathode copper is electrowon directly from the purified pregnant liquor. The spent electrolyte is recycled. Nitrogen oxides evolved from the leach are reconverted to nitric acid and are also recycled. Sulfur is rejected as So, jarosite, and gypsum. The process is highly versatile and can recover precious metals, molybdenum, and zinc when these elements are present. Continuous, integrated, semi-pilot plant operations using chalcopyrite ores demonstrated 99% copper leaching and production of cathode grade copper. Economic evaluation shows that the process is competitive with pyrometallurgical and other hydrometallurgical processes.

Jan 1, 1982

By James W. Lower

IN developing the orebody on lower levels of the Star mine at Burke, Idaho, Hecla Mining Co. is faced with a serious problem in driving raises. Levels are at 200-ft intervals. As a raise is being driven between levels, at points about 70 and 130 ft from the sill, heavy pressure arches develop and the raise becomes extremely hazardous. Eventually, following a blast, caving occurs, making it impossible to recover the raise. In February 1957 it was decided to attempt sinking a small winze on the vein from the 5500 to the 5700 level. This shaft (winze-raise No. 2) was to be used as a raise prior to stoping. It was assumed, and correctly, that the heavy ground pressure could be controlled by timbering close to the bottom after each advance.

Jan 7, 1958

By Robert E. Tally

THE membership of the American Institute of Mining and Metallurgical Engineers is composed largely of technicians, operating engineers, and executives in the mining, metallurgical and petroleum industries. The Institute also has its student, junior and associate membership and its Woman's Auxiliary. Primarily, it is a technical society, devoting itself largely to the encouragement of progress within the industries it represents, and to the discussion and dissemination of facts regarding this progress to its membership. The wisdom of this policy is reflected by the prestige and position which the society has gained, not only .among its members but throughout the entire mining world.

Jan 1, 1932

By Joseph A. Gill, Ernest A. Curth

The Government and Leeco concluded a cost-sharing agreement in 1976 to demonstrate longwall mining of a thin coalbed, 1 m or less, in a mine near Hyden, Ky. A premining investigation laid the groundwork for mine design and equipment specifications. Four- legged shields, a face conveyor, a stage loader and an in-web shearer were selected to operate on a 183 m face. Lengwall mining began in 1979 and initially was slowed by low mining height and equipment problems. A rock mechanics program provides early warning capability and criteria for future mine design. Monitoring of surface effects is included.

Jan 1, 1981

By Donald L. Birkimer

GENERAL INTRODUCTION To paraphrase comments made by Black and Hoek(1) on the status of rock mechanics, the general methods of applied science related to rock mechanics are: a. Observe the phenomena of nature as they occur and, wherever possible, quantify the observations. b. Propound a model or theory to explain the phenomena observed. c. Test and develop the theory by further experimentation in the laboratory and in the field. d. Use the theory developed to predict behavior in similar or extended circumstances. e. Insure by measured experiment and observation that the predictions made are valid, or that deviations from the predicted behavior can be accounted for. f. Modify the theory and practice as necessary, and continue the process until more general laws can be formulated and applied, with a useful degree of confidence, to practical problems. This paper will present an infant concept. It will, in fact, propound a possibly useful theory to help explain commonly observed phenomena. It will test and develop the theory for a material similar in nature to some rocks. It will be used to predict behavior in the extended circumstances of a

Jan 1, 1971

By E. L. Swarts

In the course of a program on high-temperature processing and electrowinning of uranium at the Knolls Atomic Power Laboratory,'' it became necessary to give attention to the interaction of molten uranium with graphite. Although it is known3 that a protective interface layer may form, details of this reaction have not been reported. Unfortunately it was impossible to complete the planned experimental program. However, the general problem is considered of sufficient interest to warrant reporting those preliminary results actually obtained. EXPERIMENTAL PROCEDURE Interface carbide layers were formed by melting samples of cleaned uranium metal in small closed graphite crucibles. Equilibrations were conducted in vacuo or in an atmosphere of dry helium at temperatures ranging from 1150" to 1400°C and for periods of from 24 to 240 hr.

Jan 1, 1960

CHICAGO SECTION CHARLES H. MACDOWELL, Chairman, LUTHER V. RICE, Vice-chairman, HENRY W. NICHOLS, Secretary-Treasurer, Field Museum of Natural History, Chicago, Ill. ALEXANDER K. HAMILTON, G. P. HULST, HENRY P. HOWLAND, FREDERICK T. SNYDER. A meeting of the Chicago Section was held at the Chicago Engineers' Club on the evening of March 30, 1918, on the occasion of the visit of the President, Vice-president. and Secretary of the Institute. The meeting was called to order by Henry W. Nichols, Secretary of the Chicago Section. The first speaker of the evening was Mr. Allen, Deputy Fuel Administrator for the State: of Illinois, who spoke on the problems and difficulties encountered by the Fuel Administration during the past -winter, He paid high tribute to the spirit of cooperation shown by the

Jan 5, 1918

By F. R. S., B. Hopkinson, R. Hadfield

A short time ago Professor Stoughton askes the writer if he would present a paper for the Feburary meeting of our Institute.

Jan 1, 1915

By Fred R. Harris

INTRODUCTION MacMillan Tungsten is located in northwestern Canada on the border of Yukon and Northwest Territories at a latitude of 63º17' and altitude of 1800 m above sea level. The deposit lies within the Selwyn Mountains 10 km from the Canol Road. It is 660 km by road from Whitehorse, Yukon, and 1325 km by air from Vancouver, British Columbia. MacMil lan Tungsten is a contact metasomatic deposit in gently dipping Lower Paleozoic limestone and limestone breccia adjacent to a Cretaceous quartz monzonite stock. Four tabular tungsten skarn horizons contain total geological reserves of 30 million tons grading 0.9% WO3. DISCOVERY AND HISTORY J.F. Allan, a former AMAX geologist, located mineral claims in September, 1962, to cover the source of scheelite-bearing skarn float found in the headwaters of Cirque Lake Valley. Exploration work on the property conducted mainly between 1968 and 1973, includes geological mapping, 10,500 m of diamond drilling in 73 holes, and 735 m of underground exploration. Mil 1 tests were carried out on a 300 ton bulk sample obtained underground. Preliminary feasibility studies, collection of weather data and a variety of environment studies have been carried out since 1973. Although no production date has been set MacMillan Tungsten will undoubtedly be a major tungsten producer.

Jan 1, 1976

By S. W. Parr, F. B. Hobart

Studies relating to the behavior of coal toward oxygen may have for their purpose the determination of the fundamental factors that underlie spontaneous combustion, weathering and deterioration, and the general topic of storage, as well as those properties that have to do with the underlying principles of carbonization. There is also involved the possibility of developing information relating to the constitution of coal, or at least the chemical properties inherent in the type substances of which the coal is composed. It is the purpose here to record certain results bearing on this latter idea of the chemical properties that characterize the main constituents of bituminous coal. The avidity of freshly mined coal for oxygen has long been known. What happens to the coal or to the oxygen is not so clear. Is the oxygen absorbed or chemically combined, and what are the conditions as to time, temperature, texture, or components that are most involved in the phenomenon? If we subject a weighed quantity of coal maintained at a constant temperature to a current of oxygen, we may obtain three factors of interest—the weight increase of the coal, the weight of the water, and the weight of the carbon dioxide formed in the reactions involved at that

Jan 1, 1925

While mining silver at Butte in 1882, Marcus Daly is reputed to have told his partners in The Anaconda Silver Mining Co., "It looks rather gloomy. The vein is running into copper." Recently, The Anaconda Co. authorized an $11 million expenditure to be made over the next five years to ensure their "running into copper" at deep levels for many more years. The new development program is designed to permit both deeper and more widespread selective mining in "the richest hill on earth" by means of additional shaft-sinking, reactivating closed mines, and establishing new haulageways and centralized hoisting facilities. Historically a deep level selective mining camp, Butte will now continue its uncommon use of three main types of mining methods at one camp-selective mining, block caving, and open pit mining. It was thought by some people that the construction of the Kelley shaft and the subsequent beginning of block caving operations in 1952-outgrowth of the Greater Butte Project-signaled the end of stope mining of high-grade ores at depth. This feeling became more pronounced when, in 1957, the Berkeley open pit commenced operations. During recent years, the tonnage of ore mined selectively underground has decreased, but the new program will maintain the position of selective underground mining in the overall picture of the Butte operations for many years to come.

Jan 7, 1960

By Samuel M. Cassidy

The exact date of man's first use of coal is lost in antiquity. The discovery that certain black rock would burn was undoubtedly accidental and probably occurred independently and many times in the world over thousands of years. It is quite likely that these independent discoveries were made when primitive man chanced to build camp fires on exposed ledges of a black stone, then was amazed when it caught fire. The Chinese recorded the use of coal 1100 years before the Christian Era. And, from the Bible we learn that King Solomon was familiar with coal in what is now Syria. In Wales, there is evidence that the Bronze Age people used coal for funeral pyres, and it is known that the Romans used this fuel. There are other ancient references. So the knowledge that coal would burn, and even some uses of that knowledge, goes back for thousands of years. However, practical and consistent use of coal seems to date to England in the Middle Ages. COAL IN AMERICA In the Americas, there is evidence here and there of a slight use by the Indians. However, the first recorded discovery of coal, in what is now the U.S., was by French explorers, who reported a "cole mine" on the Illinois River in 1679. Following this, other discoveries were made by French and British explorers, but the first recorded actual usage was in Virginia in 1702, where a French settler was granted permission to use coal for his forge. Earliest recorded commercial mining was in 1750, from the James River coalfield near Richmond, Va., a deposit now abandoned. Besides local consumption from this field, shipments were made to Philadelphia, New Pork, and Boston. During the Revolution this coal was of importance in the manufacture of shot and shell; so important, in fact, that the British sent an expedition in 1781 to destroy the iron works and

Jan 1, 1973

By Hans Lundberg

AFTER the war years, great activity has been shown in geophysical exploration for ore. The appreciation by mining and government geologists of geophysical techniques and results is largely responsible for the popularity of these methods. In Canada, plans are being made to study, by geophysical methods, the structure of a portion of the Pre-Cambrian shield in the hope that such studies will not only give a clearer picture of the geology, but will be of direct aid to the mining companies when selecting areas for detailed prospecting. Although geophysics thus has become more popular, some engineers are still reluctant to employ the methods to their full extent. Allotted funds are often rather low, so that the least expensive

Jan 1, 1947

By John A. Graves

Anaconda's Jackpile-Paguate mine, located between Albuquerque and Grants, N.M., is situated at an elevation of 6000 ft in a semi-arid desert region. The original Jackpile deposit was discovered by Anaconda air and ground exploration parties in Nov. 1951. A large percentage of the uranium mined in New Mexico comes from the Jackpile-Paguate, which is one of, if not the largest, open pit uranium mines in the world. From 1953 to the present, 120 million tons of overburden, mining waste, and low-grade material have been removed to produce approximately 10 million tons of merchantable uranium ore, having an average grade of about 0.25% uranium oxide. Identifying the Orebody Surface drill holes delineate the ore bodies on a predetermined grid which varies in dimension but usually affords 100-ft control. These holes are probed immediately after drilling by geophysical logging trucks, resulting in a gamma log and digital readout from each hole. From this information it is possible to arrive at an almost immediate conversion to percentage of U3O8 on 6-in. intervals. Initially a hole is probed at a reconnaissance speed of 10 fpm with a time constant of 8 sec. Wherever the gamma recording goes off scale on an initial run, that particular zone is rerun at 2 fpm and at a time constant of 2 sec. This time constant is the interval that emissions are counted and accumulated for recording purposes. The search radius of the Geiger probe is approximately 18 in.

Jan 8, 1974

By J. C. Mertz, C. H. Mathewson

Accurate knowledge of the solid solubilities of the elements that dissolve in the important base metals is needed for guidance in the preparation and heat-treatment of the alloys derived from these components. While there is still difference of opinion concerning the merits of the X-ray and microscopic methods of determining such solubilities, it is certainly true that the recent extensive use of X-ray diffraction to review the existing constitutional data has revealed many glaring inaccuracies and has brought about a much improved knowledge of phase-boundary locations, which will inevitably come to include all of the important alloy systems. When the work is done with all necessary precautions it appears that in the majority of cases where the solubilities extend beyond a few tenths of a per cent the X-ray back-reflection technique is capable of furnishing the best of information in this field. For the most prolonged and thorough studies it is obviously advisable to combine the results of several methods, in particular, to obtain an agreement between X-ray and microscopic data. This paper reviews the work previously done on the solubilities of phosphorus, arsenic, antimony and bismuth in copper and, in consideration of the uncertainties thus made apparent, presents new X-ray data obtained with the first three members of this group. Copper-phosphorus System Heyn and Baurl found that in slowly cooled alloys phosphorus forms a solid solution with copper up to about 0.175 per cent. Huntington

Jan 1, 1937

OUR 78th Annual Meeting was, technically and attendance-wise, one of the greatest to date. No one who came to New York's Hotel Statler had time to hear all 266 papers, or to attend all 70 sessions and 27 committee meetings, or to shake the hands of the more than 3000 engineers, educators, students and executives who attended-but no one was lost in the crowd. For crowds always dwindle down to groups of two and three and four, and those are the little sessions which make our meetings well worth attending. Herewith four pages of photographic highlights and sidelights on the February gathering.

Jan 3, 1950

By Lysle E. Shaffer

TEACHING engineering students how to write and speak effectively -is one of the greatest problems facing the technical schools today. No phase of engineering education has received more criticism, and rightly so, for the criticism is justified. Year after year we continue to graduate men that are indifferent to the use of a tool they will need every day of their lives. Our young engineers cannot write a clear, concise report, and their business letters are a disgrace to the profession that takes pride in precision. The problem is not new. The remark ascribed to Sir James Barrie, that "The man of science appears to be the only man who has something to say, just now-and the only man who does not know how to say it" is as uncomfortably true today as it was thirty years ago. The records of meetings of engineering educators and the transactions of the engineering societies show that the inability of the engineer to communicate his ideas has been discussed for years. Engineering educators, prodded by industry, have recognized that the problem exists, but they have not solved it. Instead they continue to expose the student to composition and rhetoric, hustle him through English and American literature, and then blame his high school because he does not know enough English grammar to write a clear sentence. We must face the fact that the graduate is not going to reflect on the high school, but on his college. If the high school has shirked the job, the responsibility for correction rests on the faculty of the professional school.

Jan 1, 1948

By Oliver Bowles

When a new type of equipment revolutionizes methods of quarrying one kind of stone, producers of other kinds focus their attention on its potentialities in their particular fields. The purpose of this paper is to discuss the accomplishments of the wire saw in slate, to show its more limited attainments in other kinds of stone, and to point out the possibilities of much wider application. A wire saw consists of a 3/16-in. or ji-in. three-strand wire cable that runs as a belt and cuts the rock by abrasion. (Fig. 1. The teeth of the saw are sand grains carried in the grooves between the strands. Accomplishments in Slate† Initial experiments with wire saws by the U. S. Bureau of Mines in the Colonial Slate Quarry, Wind Gap, Pa., in 1926, attained success so immediate and pronounced that within two years in virtually every quarry in the neighborhood of Wind Gap, Pen Argyl and Bangor, the most productive slate area in the United States, wire saws were substituted for channeling machines. An 80-ft. cut in slate is shown in Fig. 2. The technique of operation has been described in several reports (references at the end of the paper). The present purpose is to summarize the accomplishments in a large, typical slate quarry after nine. years of experience. Parsons Bros. Slate Co., at Pen Argyl, Pa., substituted two wire saws for six channeling machines in 1927. The following comparisons are made between the present method with wire saws and the former channel-ing-machine method. Rate of Sawing.—The average rate of cutting with a wire saw in the early days of its operation, as determined by the Bureau of Mines', wits 14 to 17 sq. ft. per hour. Parsons Bros. Slate Co. estimates the present rate of cutting at about 25 sq. ft. an hour, whereas the channeling-rnarhirle

Jan 1, 1938