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By J. A. Bownocker

THE Pittsburgh is one of the most important coal beds of Ohio. It was the last of the great coal beds to be worked extensively in that State, has the largest area of virgin coal, and will in all probability be the last of the great deposits to be exhausted. The line of outcrop sweeps nearly southwest in a sinuous line from Jefferson County on the north to Lawrence on the south, a distance on a bee-line of at least 150 miles. (Fig. 1.) The maximum width of the area under which this coal is due is about 55 miles, but in most places it is less than half that and in the two southern counties it is in places restricted to narrow ridges. Here as elsewhere the Pittsburgh coal forms the base of the Monongahela formation, and the following section taken from Condit shows the position of this bed with reference to certain higher ones in this field:1 FEET INCHES Shales and thin beds of limestone 24 5 Coal, Meigs Creek, No. 9 4 0 Shale, sandy 11 0 Coal 0 8 Shale, clayey 6 0 Coal, Lower Meigs Creek 3 0 Shales,clayey 2 0 Limestones and thin layers of clay 25 0 Unseen 11 0 Coal, Redstone 2 0 Unseen 11 0 Coal, Pittsburgh, No. 8 8 0 Clay 5 0 Limestone 4 0 From the standpoint of continuity the Pittsburgh coal of Ohio must be classed with the patchy type. As the map shows, the coal is thin or wanting along many miles of the line of outcrop. The large deposits form three separate areas, which, in order of their importance, are generally known as (1) the Belmont, (2) the Federal Creek, and (3) the Gallia fields.

Jan 10, 1926

By Helmer Hedstrom

THE purpose of this paper is to direct attention to the importance and the usefulness of phase measurements in electrical prospecting for ore, a subject about which virtually nothing has been published. The paper describes a new field method for ore prospecting, the "Turam" method, which makes use of phase measurements, and which has been used with great success for five years. Of the principal geophysical prospecting methods, the gravimetric and magnetic methods determine the direction and strength of the static fields of force of the earth. By seismic and electrical methods, fields of force are applied to the block of ground under investigation. By these methods a third parameter can be measured, besides the direction and strength of the field; namely, the time of arrival of the applied field at the different observation points. This time of arrival has been practically the only parameter measured in seismic work, while in electrical pros-pecting it has generally not been considered, the measurements having been limited to determination of direction and strength of the applied field.

Jan 1, 1937

By J. D. Miller, P. J. McDonough, H. Q. Portillo

Previous investigations have demonstrated the catalytic effect of silver additions in the ferric sulfate leaching of chalcopyrite [ ] The enhanced rate of leaching was found to be due to the formation of an intermediate Ag S film which forms on the Cures2 surface by an exchange reaction Under these conditions, unlike the uncatalysed ferric sulfate leach, the elemental sulfur forms a nonprotective reaction product on the Ag S crystallites As a result, the rate appears to become limited by an intermediate electrochemical reaction in {he Ag2S film rather than by transport through the elemental sulfur reaction product [ ] The reaction rate was found to have a complex dependence on the Ag+, Fe++ and Fe+3 concentrations, but independent of the Cu concentration Electrochemical measurements with a Ag,S-coated chalcopyrite electrode provide further information regarding the nature of the reaction mechanism The kinetics of the rate limiting, intermediate electrochemical reaction are analyzed in terms of the Butler-Volmer equation

Jan 1, 1981

By R. R. Sayers

VENTILATION may be defined as the process by which vitiated air of an inclosed or partly inclosed space is continuously replaced by fresh air. Fresh air has been defined as invigorating pure air. Pure dry air at sea level contains the following gases:1 Analysis of Air at Sea Level PER CENT. Oxygen 20.94 Nitrogen 78.09 Carbon dioxide 0.03 Argon 0.94 Helium, krypton, neon, xenon, hydrogen, hydrogen peroxid, ammonia, ozone traces CARBON DIOXIDE LIMIT For many years carbon dioxide was used as an index of the purity of the air vitiated by the metabolism of people. It was, however, well known that the untoward effects produced on those exposed to such air was not due to the concentration of the carbon dioxide. It has been found that the untoward effects on the comfort and efficiency of those so exposed are due to the increased temperature and humidity. It has been found that men can breathe air containing many times the amount of carbon dioxide found in our worst ventilated theaters and assembly halls, which, according to Rosenau, do not contain above 0.5 per cent. carbon dioxide.

Jan 7, 1926

By O. N. Wampler

UNDERGROUND lighting in the zinc mines of the Tri-State district can be separated into four di-visions. 1. Foot of shaft. 2. Pumps, fans. incline hoists and other stationary machinery. 3. Haulage ways. 4. Headings and stopes. One of the main improvements in lighting around the bottom of the shaft is in the use of skidoo flash lights, which have replaced the old electric skidoo bells. These bells were used as signals from the hoisterman to the tub hooker. In the event that a can bumped the side of shaft or a rock spilled from the can when dumping; the hoisterman rang the skidoo bells as a signal for all to leave the vicinity of the shaft bottom on a dead run. These bells were much better than no signal at all, but many of them were often out of order; the worst feature being that when out of order this fact was not immediately indicated. The electric flash-light signals work on the opposite principle and are burning at all times except when the hoisterman breaks the circuit when signaling danger. Therefore should a break or short occur in this arrangement, the shaft bottom is immediately thrown in darkness. Since the reaction from the eye is quicker than from ear, there is a slight saving of time- to the men escaping from the point of danger. Even this brief period of time may save a life. One other, point, to be emphasized, is that all lights near the shaft bottom should be on the signal circuit so that the entire area is momentarily darkened. I. have inspected mines where only one or two lights are used as signals, with the remaining lights around the shaft on another fixed circuit. In this case the flashing of the signal lights is almost drowned out by the stationary lights. These flash signals must be as startling as possible, which can only be done by flash-ing all the lights.

Jan 6, 1928

By F. J. Zuiderweg, G. G. Bemer

Results of a study aimed at assessing kinetics and mechanisms of the batch agglomeration process in suspension are discussed. A recently developed light backscatter technique which enables the increase of average particle size from 1 to 5000 µm to be followed, was used to determine agglomeration kinetics. Growth curves and agglomerate size distributions were obtained in a stirred vessel for various model systems and operating conditions. Four distinct growth regimes were identified, i. e. the flocculation regime, the zero-growth regime, the fast growth regime, and the equilibrium regime. Further, it was observed that large differences in the occurrence and duration of these regimes resulted from small variations in parameters, such as size distribution of the initial particles and the binding-liquid to solid ratio. Mechanisms that determine the occurrence of the relevant regimes are discussed. The growth process was described in terms of population balance equations. In this way, the growth rate, the equilibrium agglomerate size distribution, and the evolution of the agglomerate size distribution were generated. The agreement with experimental results is satisfactory.

Jan 1, 1980

By Jan M. Mutmansky

A knowledge of rock characteristics forms the foundation for the application of rock mechanics to engineering works. Hence, there has been an increased interest in the determination and proper utilization of rock properties data. Most numerical values quoted for rock properties are obtained from arbitrary tests and are not necessarily indicative of any intrinsic rock characteristics. Recent attempts to correlate these properties by statistical methods have attracted considerable attention, in the hope that these might give some clue to the fundamental properties. To date, correlation and regression techniques have been employed for this purpose. The use of statistics has also been deemed appropriate because of inhomogeneity and anisotropy in rocks. The problems have been further compounded by the lack of standardized methods of measuring rock properties. The various ASTM committees are still deliberating on these matters, but recommendations should be forthcoming in the near future. As more reliable data become available, the ability of geoscientists to find more meaningful relationships between rock properties will be greatly enhanced. The objective of this paper is to outline another statistical technique which might be useful in providing an insight into the relationships that exist between rock properties. This method does not attempt to predict rock characteristics, but rather compares the similarity or dissimilarity between properties. This enables rock properties to be classified into groups with similar intrinsic characteristics. The technique described is one form of factor analysis. It allows the results obtained to be depicted geometrically, so as to make ready visual examination possible.

Jan 1, 1968

For the past several years the policy of a large section of our mining industry in relation to our present bureaucratic form of government has become increasingly amusing, if not a little disgusting. In the past, mining men have always featured themselves the self-announced champions of free enterprise, and, generally, this conviction, was substantiated by their deeds. In recent years, however, a large group of the industry, while still expounding, from the front porch, the principles of free enterprise and a sound economy based upon the law of supply and demand, have gone around to the back door with palm extended, to join labor, farmers, bureaucrats, and other pressure groups to get their share of the take. The procurement of subsidies, bonuses, increased metal prices, and government assistance in a multitude of forms seems to have obscured from their thinking the welfare of the country as a whole and the sounder economic principles of a balanced budget and lower taxes. At the recent Colorado Mining Association convention in Denver, I. was alarmed to see just how far this specialinterest type of thinking has progressed within the mining industry. Government assistance to mining. was generally considered inadequate, and a flat bonus for any new mineral discovery was proposed. It was disquieting, too, to learn how far the federal alphabet agencies have entered into the mining industry and of the thousands of highly paid technical. men on the federal payroll required to man these numerous overlapping agencies and bureaus. Now all this is very fine, and some aspects of the federal give-away program can be very appealing to the unsuspecting in the mining industry as they have been to those in other groups. Some of these expensive programs may bring about a few dividends or even several new mines. But to this whole line of pump-priming reasoning there is one big disastrous fallacy.

Jan 1, 1952

By N. E. Norman

During the past few years the underground mining industry and the big hole drilling industry have been involved in a flirtatious courtship, but until recently this courtship did not appear to be taken too seriously by either party. However, many of the promises made by the big hole industry are beginning to come true. Improvements have been made steadily in techniques of mechanical boring of large diameter shafts, raises and tunnels, thus making the big hole industry a more stable partner in the eyes of the mining industry. The mining industry too has made many changes in planning that make mining more attractive to the big hole industry. If there is to be a marriage between big hole drilling and mining, we should certainly take a look at the background of the big hole drilling industry, and examine the three main features of big hole drilling to determine how each applies to mining. Shaft Drilling Since 1950, numerous large diameter shafts have been drilled using rotary drilling techniques. Most of the larger diameter shafts have been drilled for the AEC for underground nuclear testing purposes. However, since 1960 several shafts have also been drilled for various mining companies, particularly in the United States. In 1967, rotary drilling shafts were either completed or in progress at the mining companies listed in Table I.

Jan 6, 1968

By Prince Gelasio Caetani

PRESIDENT DWIGHT'S invitation to be a guest of the American Institute of Mining and Metal-lurgical Engineers was the first of the subsequently very numerous invitations to dinner I have received from my American friends. When I received his telegram I had not yet been even formally appointed Ambassador. I cannot tell you how deeply I appreciated it. It was a hearty welcome in returning to your country which has been for me a second home and it came from the American mining brotherhood which has been my second family.There are two distinct periods of learning in life. The first one are the years spent in school where we learn many things we after-wards forget; the second one are the years of prac-tical apprenticeship which engrave indelible signs in a man's character and shape his life. These latter years I spent in the United States and they have influenced the whole course of my life. I owe very much to my American friends who trained me. The earliest was Prof. Robert Peele, of Columbia University. At the Daly West mine, in Park City, Utah, he curbed my futuristic English spell-ing and had a hard time at it. Prof. James F. Kemp taught me that geology is a guess work just as unre-liable as the prediction of international events; he taught me also that a frank, honest and loyal character will lead a man equally straight through a mining report and through public life.

Jan 3, 1923

By F. B. Speaker

MUCH of White Pine's success is due to the mechanization of mining operations and the development of an efficient beneficiation process to extract usable copper from the low-grade ore (averaging slightly more than 1 pct copper content). When the mine was first opened, all ore was trucked to a conveyor system installed in the slope leading out of the mine. But as new mining areas have been opened up at increasing distances from the slope, conveyors have replaced the trucks for much of the haulage. This conveyor program is expected to continue as mining progresses. Here is how the present underground system functions: Run-of-mine ore is dumped into two truck hoppers and withdrawn from the bottom of each hopper by a 60-in. apron feeder 22 ft long (see diagram). Collecting conveyors 54 in. wide and 44 ft long receive the material from the apron feeders and discharge to two main-line 54-in. conveyors, one 2000 ft and the other 2600 ft long. Operating at 312 fpm and handling 1200 tph, the main-line conveyors converge near the bottom of the tunnel leading out of the mine and discharge into two 72x168-in. Vibrex screens. Ore under 8 in. goes directly to the bin beneath. The oversize is fed to two 32x40-in. jaw crushers and after crushing joins the 8-in. material in the bin.

Jan 12, 1957

Within the last century, and largely during the latter half of it, the increase of our knowledge of the development of man, both in his search for a livelihood and for power, and in the growth of his reason and conscience, has been greater than all we had known before. The great interest in all kinds of archaeological work and the many excavations made of buried and long forgotten places has put at our disposal historical records not available, and in many cases not known before, and a study of these and other records of human progress from paleontological and geological sources has given us a much broader view of what we call "civilization" than was possible even a short time ago. The old idea that men were created with fully developed minds, speech and reason has yielded to the view that in the upward progress of the human race the development of the mind and reason has been a comparatively recent occurrence, as we think of the half million, and probably more, years that have passed since our earliest records of man were made. The traits that come to us without effort

Jan 1, 1935

By Harry Tufft

FOR many years the treatment of mine timbers with preservatives was confined to a few pioneer plants in the United States, and it is only in the past few years that the practice has grown appreciably. In a field study of the mine timber situation in Illinois, Pennsylvania, and further study of the situation in the country as a whole, I found that most mine operators did not keep records on mine timber that would afford the necessary data for determining the possible savings from preservative treatment. Some primary questions the mining engineer should be able to answer before making his decision on preservative treatment. for a particular mine are: (1) Quantity and cost of timber going into permanent workings annually; (2) quantity and cost of annual replacements due to decay; (3) life of untreated timber in different places; (4) desired life of timber. With the necessary facts in hand, he can then con-fidently select a method of treatment and preservative that is best suited to his needs. In former years when timber was cheap and an abundant supply could be had close at hand, as was the case in the majority of mining regions, the mine op-erator did not concern himself much except to see that enough was supplied to keep the workings safe. The cost figure for timber and labor, distributed to cost per ton of ore, was all the bookkeeping necessary. With present costs of timber, labor, and increasing length of haul to the mine, many operators are paying closer attention to timbering costs and studying them in. more detail. Some of the larger and more progressive opera-tions now keep detailed' figures that give information on all phases of their timber problems. However, at the majority of mines the data available do not permit such analysis. Checks as to where the different con-signments are placed, the date of setting, and the period

Jan 6, 1927

By Raja P. Upadhyay

An evaluation of the economics of mining the deep, thick oil shale deposits of the central portion of the Piceance Creek basin, Colorado, U.S.A. is presented in this paper. For the analysis, a modified large scale underground mining system developed by Cameron Engineers, Inc. and the Gas Combustion retorting process developed by the U.S. Bureau of Mines were used to determine capital investment and annual operating costs. A modified risk analysis computer program was then used to calculate DCFROI’s for various grades of oil shale and selling prices of partially refined shale oil. Sensitivity analyses were performed to quantify the affect of bonus bid payments, operating costs, capital investment, and all costs on DCFROI. In addition, a probabilistic evaluation was made to determine the risk involved in obtaining desired rates of return. Results of the economic evaluation indicate that for current selling prices of crude oil a high risk is involved in obtaining a DCFROI of 15%, unless only higher grades of oil shale are mined. However, mining only the higher grade oil shales, 125 l/mt (30 gpt) and above, would effectively reduce the potentially mineable resources by 90%. Risk can also be reduced through higher selling prices of shale oil. Sensitivity analyses indicate that the capital investment has a three times greater effect on required selling price than total operating costs.

Jan 1, 1977

By V. S. Rood, J. A. Norden

The general system of workings at the Utah-Apex is similar to that found in many of the western metalliferous mines. There is a vertical three-compartment shaft extcnding to the surface, from which the various levels have been driven to the orebodies. The 1000-ft. (305-m.) level, about 3/4 mile long, was driven as a haulage and drain adit. Geology The formation is a flat north-dipping series of alternating limestone and quartzite beds. Extensive north-south faulting and fissuring have taken place, resulting in the formation of large replacement orebodies in the crushed zones in the limestone. The orebodies are irregular in shape and size, but follow closely the trend of the mineralizing fissures. The ore consists of galena, pyrite, sphalerite and small values in silver and gold. Large masses of non-commercial pyrite are frequently found in or adjacent to the orebodies, and more or less pyrite is found for some distance in the walls of the orebodies. Lenticular bodies of a black pyritic shale also occur in the zones where extensive faulting has taken place. Mining Methods and Condition of Workings Geological conditions, mentioned before, have made the ground extremely heavy. In mining above the 1000-ft. level, square-set and filling methods were used, but not altogether successfully. The crushing of timbers extended even into the filled portions of the stopes. The filling material itself, consisting of limestone, shale, and pyrite, possessed swelling qualities which added to the difficulty of maintaining

Jan 1, 1920

By Julian Kennedy Edgar

THINKING that it may prove of interest to the Institute, I have prepared a short account of the blowing in and subsequent working of the "A" furnace of the Edgar Thomson Steel Works. This furnace was built for the purpose of making spiegel, but has been started and is now running on Bessemer iron. The shape and size of the furnace are shown in the accompanying drawing. It will be seen that the section is formed of lines making very small angles with each other. In fact, an arc of a circle can be drawn, from the top to the tuyeres, which will nowhere deviate more than two inches from the lines given. In building, also, great pains were taken to gradually round the angles, so that the most careful observer, standing in the crucible and looking upward, could not tell at what points the slopes changed. It will also be seen that the widest part of the furnace is almost exactly midway between the bottom and the stock line, The flattest slope is maintained for 20 feet above the crucible, and is about 1 s inch to the foot from the perpendicular. The furnace is lined with small brick throughout, and has six tuyeres four inches in diameter, which project seven inches inside of crucible. There are three Siemens-Cowper-Cochrane stoves, each 15 feet in diameter by 50 feet high. Blast is furnished by an upright engine with 32-inch steam cylinder, 84-inch air cylinder, and 48-inch stroke. The steam cylinder has balanced poppet valves, working horizontally. The steam valves are worked by a Porter link-movement in order to obtain a variable cut-off. The exhaust valves are worked by a separate eccentric. It is intended to attach a governor to the cut-off, but at present it is set by hand. The steam cylinder is

Jan 1, 1880

By W. P. Sykes

TUNGSTEN serves mankind in two major roles. The first of these is represented by the tungsten filament of the incandescent electric lamp, a common article of commerce. In the field of hard alloys it plays its second substantial part. A fortunate combination of physical properties in this metal ac- counts for its efficient service as a source of illumination. Tungsten melts at about 3400°C, has a relatively low vapor pressure and at the same time sufficient strength, both hot and cold, to serve satisfactorily as filaments, which may range in diameter from 0.060 to 0.0005 in. In the early days of the incandescent lamp, the pioneers realized the importance of using a substance of high melting point for the source of light. The metals osmium (mp approx. 2700°C) and tantalum (mp approx. 2850°C) were both employed to some extent. Tantalum actually attained some commercial importance in this field because it could be drawn into small wires of appreciable length. DUCTILE TUNGSTEN WIRE Before the year 1908, tungsten was considered a nonductile metal, since no one had succeeded in overcoming the brittleness so typical of the unworked metal at room temperature. The methods employed today in producing ductile tungsten wire were developed over a period of years. The process was largely determined by the exceedingly high temperature required to melt this metal. Even today the difficulties involved in producing an appreciable quantity of pure

Jan 1, 1953

By Don Blackmar

THE production of non-ferrous secondary metals has become a large and important industry in the United States, and deals with practically every type of manufacturing concern.. Its business is unique in that it generally buys from its customers as well as sells to them, whether they are individuals, cities, corporations, or the United States government. Its operations are of vital importance to the success and prosperity of many of the nation's most important manufacturers; yet there are few industries about which less is generally known by those outside it, whether concerning the magnitude of its operations or the details of its actual technique. The industry itself is to blame for this meager publicity, because its technical men have made few attempts to openly exchange ideas, in spite of the excellent examples set by the iron and-steel or the copper and brass industries. Whether this is due to the ancient shroud of secrecy generally supposed to cover smelting operations, or because its technical men actually felt that the industry was too puny to be interesting, is hard to say. This paper will consider its subject in a 'general way, attempting to show something of the size and importance of the industry, as well as its fitness to do its work well. Attention will be called to the sound economic reasons for the handling of non-ferrous wastes by specialists, and to the often unseen losses of metals and labor which occur when manufacturers reclaim' their own metallic wastes.

Jan 1, 1928

By Cyril Smith

THE method of thermal analysis, so important in the development of metallographic science, has of recent years been falling into disuse owing to the development of other physical methods which give results easier of interpretation and which can be used for the study of either equilibrium or transitional conditions because they do not require a continuously changing temperature. Nevertheless thermal analysis remains useful in the study of reactions that take place rapidly, and the simplicity of the experimental technique and the general availability of the apparatus involved are points in its favor. Theoretically, thermal analysis is capable of giving specific and latent heat measurements and therefore should permit the study of reactions on a more fundamental basis than any other method. It is, however, difficult or impossible to obtain quantitative heat measurements from cooling curves obtained in the usual way. Even if the furnace containing the sample is cooled or heated at a linear rate, or if a gradient furnace is employed to maintain a constant rate over a large range of tempera-ture, the heat flow from or to the specimen depends on its previous his-tory, for the difference of temperature between the specimen and its surroundings varies. The emissivity of the specimen surface, moreover, is unlikely to be constant. The able mathematical analysis by Russell,1 although it prevents misinterpretation of data, has an effect rather the reverse of that intended, and leaves the reader doubtful of the possibility of ever obtaining quantitative results from thermal curves. Nothing can be done to apply thermal analysis to the study of equilib-rium conditions of reactions that are not completed at rates of tempera-ture change below about 1° C. per minute, and this unfortunately excludes most solid transformations in alloys. ? For the determination of liquidus

Jan 1, 1939

By E. P. Shea

The Anaconda Co.'s Geological Department at Butte, Mont., was started early in the Company's history because of litigation involving vein ownership and extralateral rights. The problems, some of which were resolved in courts, were many because of the large number of veins and lode locations. Defensive action was required to prove ownership and protect against illegal exploitation of the downward and extra-lateral extensions of the ore bodies. In many cases it was necessary to define the outcrop of the vein and to show that its apex was within the boundaries of the lode claim. Exhibits illustrating geology were needed to present the cases clearly, and these could be made only after careful inspection and mapping of the underground workings by competent geologists. Also, The Anaconda Co. was one of the first companies to recognize the worth of skilled mining geologists and the value of accurate records in the search for new ore. The department was organized in 1900 by H. V. Winchell who, with D. W. Brunton, worked out the methods. Reno Sales was Chief Geologist from 1906 until 1948 when he was succeeded by V. D. Perry, the present Chief Geologist. Under their direction, F. A. Linforth, M. H. Gidel, C. H. Steele, E. P. Shea, C. C. Goddard, Jr., and W. A. O'Brien enlarged the scope of the work and improved the technique.

Jan 3, 1961