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Organization Place - Date 1918 American Iron and Steel Institute New York, N. Y. May American Water Works Association :.. St. Paul, Minn. May 20-25 American Institute of Chemical Engineers Berlin, N. H.. June 19-22 American Concrete Institute Atlantic City, N. J. June 24-26 American Society for Testing Materials Atlantic City, N. J. June 25-28 New York Electrical Society New York, N. Y. June National Association of Stationary Engineers Cincinnati, 0. Sept. 9-13 National Exposition of Chemical Industries New York, N.Y.. Sept.23-28 American Chemical Society Cleveland, 0. Sept. National Petroleum Association Atlantic' City, N. J. Sept.

Jan 5, 1918

By AIME AIME

OVER-ALL operations of the oil industry, as measured by production of crude oil and consumption of products, are almost exactly of the same magnitude as a year ago. Does this mean that the great oil industry has been undisturbed by the war? Has this industry, so vital to the prosecution of the war and to the maintenance of our way of life, been unaffected in its operations? No indeed - changes within the industry are great. It has been called upon to revamp its trans¬portation methods so as to move about one fourth of the total amount of crude and refined products by railroad tank car instead of by ocean-going tankers. Its fundamental internal economy, based on maximum gasoline yield from a barrel of crude, has been relegated to memories of the past. Rationing of oil products, which has been forced upon us in face of an abundant supply, is not only disagreeable medicine but is in itself completely disruptive to the marketing end of the-business.-

Jan 1, 1942

By Edward H. Robie

THE registration badges gave out, there were not enough programs, the Pioneer Hotel's rooms were insufficient, and some hundred applicants for banquet tickets had to be turned down at the Institute's Regional Meeting in Tucson, Nov. 1-5. Minor inconveniences these, however, occasioned by the fact that, optimistic as they are in Arizona, about half again as many partook of the week's activities as were expected. For this, the local program committee can be blamed-both the technical and social features were too attractive in quantity and quality. Seriously speaking, though, the Institute has probably never had a more successful Regional Meeting than this one. It being the first that has been held in Arizona in 22 years, no effort was spared to make it the distinctive gathering that it was.

Jan 1, 1938

By E. H. Rose

IN the realm of ore dressing the most pregnant feat of all time was announced in 1945: the winning of the mineral raw materials which made the harnessing of atomic energy possible. Lost in the stupendous implications of the end result, in the two billion dollar hugeness of the project, and in the famous names attached thereto, the fact that crude uranium ores had to be concentrated received relatively little notice in the press. Only the final link in the concentrating chain was publicized-ether extraction of uranyl nitrate, developed by Hoffman and carried on by the Mallinckrodt Chemical Works, or methods developed by the Ames group under Spedding. Some of the earlier links represented less glamorous but equally difficult and exacting research. One may only speak a word of admiration for those who worked hard, accomplished much, and said nothing. The universal lament for most of the year was "man shortage." A group of Canadian engineers expressed it as "being so short of labor that no labor was available to develop laborsaving devices." . Despite this, an outstanding amount of mineral-dressing progress was made in 1945. Necessity allowed no alternative. The insatiable demand of war for minerals forced the exploitation of lower and lower grade ores, and of others not before considered of commercial character or use, requiring the mineral dresser to fight for and win new bridgeheads on the home front.

Jan 1, 1946

By O. T. Berge

Development and production from open cut mines continued its vigorous growth trend during the year 1968. Material handling and transportation were again exposed to the use of larger equipment with shovels, trucks and front end loaders leading the way. Highlights of World Mining Activities Africa: The Anglo American Corp. opened a new high-grade copper mine in Zambia during the year. In Angola, the Companhia Minera do Lobita planned a 3 million ton iron ore production for 1968 from new mines which will ultimately produce 5 million tons per year. A feasibility study of Bethlehem Steel Co., for the development of large high- grade iron ore reserves in Gabon, was in final stages of completion this year and Pickands Mather and Co. continued its investigation of iron ore deposits along the Ivory Coast.

Jan 2, 1969

By Charles A. Kliche

INTRODUCTION The Northern Great Plains Coal Province which occupies approximately 36.6 ha contains about one-half of the nation's total coal resources. About one million ha are underlain by coal that is considered to be mineable from the surface. The topography of the province is predominately plains, rolling hills, and some badland areas characterized by breaks or sharply eroded hills. Elevations range from about 1500 m above sea level on the west to about 600 m above sea level on the eastern boundary. The average slope of the ground is approximately 2 m per km. Streams in the province drain generally easterly and southeasterly (1). In the United States, the Northern Great Plains Province lies within the states of North Dakota, South Dakota, Montana, Wyoming, Nebraska, and Colorado. The coal within the province is located almost entirely in the states of North Dakota, Montana, and Wyoming. Although it is relatively low rank, the coal within the province encompasses a large portion of the total remaining U. S. reserves. The U. S. Geological Survey estimates the total remaining coal resources of the United States to be 2.6 trillion mt within 1000 m of the surface, and 2.9 trillion tons within 1830 m of the surface. Of this total, only about 177 billion mt are classified as reserves meaning that they are (1) known in location, quantity and quality from geologic evidence supported by engineering measurements, and (2) economically recoverable based on currently available technologies and current market value (2).

Jan 1, 1983

By M. C. Fuerstenau, R. B. Bhappu

The response of beryl to sulfonate flotation was examined. The dependence of flotation recovery on sulfonate concentration, pH, and the absence or presence of various ions is also demonstrated. The response of quartz and feldspar to sulfonate flotation at various values of pH is given to. show the conditions necessary for selective separation. Finally, beryl was successfully concentrated from a natural ore using a technique devised from experimental observations on systems of pure minerals. With the possible exception of quartz, the flotation characteristics of silicate minerals are rather poorly understood. This is due in part to the com- plexity of the mineral systems themselves and in part to an insufficient amount of flotation data. The complexity of the systems arises from the wide range of chemical composition that the silicate minerals can assume. This is reflected in the variability of such physical properties as hardness and cleavage. Although the chemical composition of silicate minerals can vary considerably, a general grouping can be accomplished conveniently on the basis of the assemblage of SiO4 tetrahedra in all the silicates. That is, it has been shown that six basic groups can be obtained, depending on the arrangement of oxygen sharing between adjacent silicon atoms (or substituted aluminum). When all four oxygen atoms are shared, a framework structure such as quartz or feldspar is obtained. When three oxygens are shared, infinite sheets are obtained as in the micas and clays. When two oxygen atoms of the tetrahedra are shared, infinite chains are obtained, such as those in

Jan 1, 1963

By Cyril Wells

THE diffusion of carbon in gamma iron plays an essential role in many metallurgical processes. In carburizing, in graphitizing, in homogenizing, in the formation of pearlite from austenite, and in other processes, migra-tion of carbon in gamma iron occurs.1,2 A full understanding of the rate at which these processes occur obviously requires a knowledge of the rate of diffusion of carbon. In carburizing, for example, the depth of carbon pentration is determined by the carbon concentration in solid solution at the surface, and by the rate of diffusion inward of the carbon. Until reliable data on the rates of diffusion of carbon are available it is unlikely that a full quantitative description of this process will be obtained. In the formation of pearlite from austenite, the segregation of carbon and alpha iron from the austenite obviously requires the diffusion of carbon; the rate at which pearlite nodules grow is evidently controlled at least in part by the rate of diffusion of carbon; it is unlikely that we shall understand the factors that determine the rate of growth unless data on rates of diffusion of carbon, and the variation of these with com-position, grain size, and temperature are available. Accordingly it was decided: (1) to determine, more accurately than hitherto, the diffusion coefficients of carbon in austenite over a wide temperature and a wide concentration range, (2) to study the influence of grain size and impurities on this diffusion coefficient, and (3) to study the effect of manganese and nickel on the rate of diffusion of carbon in the austenite of manganese and nickel steels, respectively; the influence of carbon on the rate of diffusion of manganese and of nickel will be made the subject of later papers. The rate of diffusion of carbon in gamma iron has been studied by Runge3 by Tammann and Schönert4, by Bramley and co-authors,5-14 and

Jan 1, 1940

By IRVING H. WENTIVORTII

(New York Meeting, February, 1912.) THE little town of San Nicolás, Tamaulipas, Mexico, lies approximately 60 miles east of Linares, situated in the State of Nuevo Leon, and 150 miles SE. of Monterey, as shown in the sketch-map. Fig. 1. The place is reached from Monterey by the Tampico train as far as Linares, a distance of 92 miles, and then by coach the rest of the way. It is situated in a narrow valley between low hills, the houses forming one main street and a plaza. It is peopled by about 500 inhabitants. The climate is temperate, the thermometer ranging from 90° in summer to a few degrees below freezing-point in winter; but this severe weather only lasts a day or two at a time, when the " northers " blow. There are no streams in the vicinity, but water sufficient for the use of the people is obtained from wells. The rainfall is about the same as that in the rest of NE. Mexico. The rainy months are July, August, and September. The rest of the year is practically dry, with an occasional showery day or two during the winter, when a " norther " is blowing. Timber is abundant in many localities. There are two varieties of oak, besides mesquite, ebony, "maguira," "patol," and a number of other kinds of trees indigenous to this region. I. HISTORY. On the discovery of the silver-lead hearing veins occurring in this district, the mining-camp of San Nicolás was founded in 1767 by the Spaniards, and numerous mines were opened and worked for a distance of abort 3 miles east and 5 miles west of the town. At the western extremity and near the Carrolena mine, a small town called San Pedro was built. The ruined walls of the houses form a single street, and all is over-

Aug 1, 1912

By C. C. Nitchie, G. S. Brooks

With the gradual depletion of the natural-gas pools of the Kansas district, together with the uncertainty of further cheap fuel developments, some of the western zinc companies turned to the coal fields, attracted by their permanency and the success of the Matthiessen & Hegeler Co. and the lllinois Zinc Co. Being then confronted with the problem of using a relatively high-priced fuel, although the ultimate supply was very great, the fuel economies of the kilns and furnaces became of far more importance, and the more modern equipments, as a result, embodied distinct gaias in this phase of the business. In addition, there have been some pronounced advances in the actual making of gas from these coals. Increased efficiency in gas making has contributed its hare to lowering costs and those plants located in the higher priced fuel districts have probably been obliged to study these economies somewhat more closely. Naturally, many beneficial changes have resulted in both practice and apparatus in these sections. On certain western coals, for instance, the actual saving in fuel consumption has been 50 per cent. By this is meant that, where about 1.75 tons were burned to smelt 1 ton of oxidized ore, 0.7 to 0.9 ton is now required. While comparisons by T. R. Ingalls1 of fuel economies in smelting in this country and Germany before the war may, in general, be correct, they do not appear to do justice to the more progressive American practice. It is doubtful whether German plants were substantially bettering these fuel ratios. Data furnished by Bender and Frams do not afford records averaging less than 0.9 ton coal per ton ore on materials from 40 per cent. to 50 per cent. zinc. Fuels As producer fuel, Illinois, Indiana, and Kansas coah offer a wide range of material, although varying much in their amenability to gasscation. The proper fuel for each plant can only be determined after com-

Jan 1, 1920

By John N. Dew, William L. Martin, `

This paper describes the results of a laboratory investigation conducted to obtain data for an evaluation of the in situ combustion process as a method of producing crude oil from reservoirs. Air and fuel requirements, rates of advance, com-bustion temperatures, and coke and fluid distributions are presented. The mechanism of oil recovery by in stiu combustion is discussed. Five crude oils ranging in gravity from 10.9 to 34.2"' API were prodrrced from a semiadiabatic, uncon-.solidnted sand pack by in situ combustion. Experimental conditions were varied over a wide range in order to determine the inter-relation-.ships of process variables. The mini-mum air flux requirement for self-sustained combustion was found to he less than 10 scf/hr-ft'l. The rate of advance of a self-sustained combustion zone was found to be nearly proportional to the air flux at the combustion front. The effects of presrure and injected air flux were studied in a series of experiments using a 21.2" API crude. A minimum air require-ment was observed at an air .flux of 20 scf/hr-ft'. The oil saturation con-sumed as fuel averaged 5.5 per cent of pore volume. The effect of air pressure was, found to be .small for experiments having high combustion eficiencies. This study should promote a better understanding of the problems and mechanisms involved in labora-tory investigations and field applications of the in situ combustion pro-cess. The data presented will be use- ful in the interpretation of results of field tests. When tempered with volu-metric sweep efficiencies, the data can be used in making preliminary economic appraisals of the process as applied to reservoirs containing high porosity unconsolidated media. INTRODUCTION The purpose of this work was to obtain laboratory data for an evaluation of the in situ combustion process as a method of producing crude oil from reservoirs. In situ combustion basically consists of (1) injecting air into a reservoir through selected input wells to create an air sweep through the reservoir, (2) igniting the crude at the injection well, and (3) propagating the combustion front through the reservoir by continued air injection. By this means, oil is swept toward producing wells in the area. The fuel for combustion is supplied by heavy residual material (coke) which has been deposited on the sand grains during distillation and cracking of the crude oil ahead of the combustion front. Recovery of petroleum by a combustion or heat wave process is not a new idea. F. A. Howard was granted a patent in 1923 on a process in which air and a combustible gas were pumped into an injection well and ignited.' Russian engineers reported on field experiments with a crude oil gasification process in 1935'. Other known early field tests include those conducted near Bar-tlesville and Ardmore, Okla., in 1942." More recently completed field tests include an inverted seven-spot by Sinclair Oil Co. in the Delaware-Childers field, Nowata County, Okla.'; a three-well and an inverted five-spot test by Magnolia Petroleum Co. in Jefferson County, Okla."."; and a test by California Research Corp. in the Irvine-Furnace field in Kentucky. The Worthington Corp. has completed a test in cooperation with the Forest Oil Corp. in Clark County, 111.l Several field tests are now in progress. Sinclair has acquired a 600-acre lease in the Humboldt-Chanute field, Allen County, Kans., and is under way with a large-scale operation. Three field tests are under way in California. The General Petroleum Corp. is conducting an inverted five-spot pattern test in the South Bel-ridge field in Kern County under a cooperative agreement with 11 other companies, including Continental Oil Co. California Research Corp. is conducting a four-well pattern test in Midway-Sunset field near Maricopa, and Richfield Oil Corp. is under way with a test in the Ojai field in Ventura County. Although the published information is valuable concerning results of field tests, little laboratory data other than that reported by Kuhn and Koch5 are available to aid in appraising the tests from a technical or economic standpoint. Engineering data needed to evaluate the process include the amount of air required per barrel of oil recovered, minimum injection rates which will support combustion, rates of advance, air required per unit volume of reservoir cleaned, amount of oil recovered, and amount of oil consumed as fuel. The present laboratory investigation was undertaken to provide these data for that portion of the reservoir swept by the combustion zone. The first phase of this investigation was exploratory in nature and was conducted at injection pressures less than 100 psig. Data were ob-

By AIME AIME

FIVE days, extending from Monday, Feb. 18 to Friday, Feb. 22, inclusive, will be required for the annual meeting this year. The first fours days will be devoted to reading and discussion of papers, general and committee business meetings, two lectures, luncheons, dinners and all the pleasures of a big, general reunion. The fifth day will be given over to an all-day excursion for both men and women by special train to West Point, in celebration of the birthday of the first President of the United States. Washington having been an engineer and now after one hundred and thirty-one years the country having selected as President another engineer in the person of Herbert Hoover, our own past president and honorary member, it is proposed to celebrate with a good old-fashioned picnic and inspect the school. The authorities at the Military Academy have undertaken to welcome the engineers and do whatever they may to make our pilgrimage notable. Other social features planned for the week are numerous. Luncheon will be served as usual at the building each day of the meeting to all members and guests. This year a very nominal charge will be made, primarily to overcome deficits due to irregular attendance. Monday noon, the Non-metallic Minerals Committee will lunch at the Engineers' Club and in the evening the Milling Methods Committee will dine there. The Annual Smoker will be held at Hotel Astor after dinner. Professional entertainment of high order is promised, but not too much to interfere with the numerous group reunions that characterize this func- tion.

Jan 1, 1929

By E. E. Schumacher

IN a laboratory devoted to the furtherance of the science of communication, the breadth and variety of the problems encountered are challenging to a metallurgist. In my own long association with the Bell Telephone Laboratories, our metallurgical group has dealt with a vast number of alloys, both ferrous and nonferrous, and with many materials in the border range of metallic properties., The objectives of our design engineers embrace every phase of telephony, and the properties they desire in metals are generally unusual, frequently unique, and often conflicting. Commercial alloys have not always been available with properties to meet a special requirement in the telephone plant, and many alloys have had, therefore, to be custom-made. Anyone who has had the opportunity to observe the results of tests of all types on numerous such alloys, both commercially and specially produced, or who has taken part in the development of an alloy of some necessary, but new or unusual combination of properties, could not fail to be impressed by the frequency with which a desired goal has been reached or adequately approached through the presence of decimal quantities of alloying elements. Nor could One fail to be struck by the occasions when, conversely, of a minute amount Of impurity element has rendered an alloy useful. It is no exaggeration to state that the content be- hind the decimal point often spells success or fail-ure, and the critical content is sometimes far to the right of the decimal point as I shall later illustrate. The great effects of small additions have long been recognized and have, in fact, been described by many investigators. The importance of the minute, however, cannot be overemphasized. Therefore, in this discussion, I propose to illustrate for you some of the startling instances, drawn primarily from our own experiences, wherein small, even vanishingly small, proportions of stranger elements in otherwise common aggregates have com-pletely changed the customary pattern of behavior. No one property has a monopoly as to being dis-proportionately affected by minor elements. Nearly all properties are affected, but there is time here to include only a selected few. I have chosen, there-fore, three of general interest: strength, magnetic, and electrical properties. I shall inquire into both the mechanisms and consequences of these disproportionate effects and try to share with you the fascination and challenge of this field. Strength Properties of Lead and Lead Alloys To illustrate the effect of the minute on strength properties I have selected lead and its alloys, with which we have worked extensively for many years. Lead has the advantages of being available in quantity in a state of high purity and of being fairly easy to melt and fabricate without contamination to any extent detectable by the spectrograph. It has the interesting disadvantages of recovery and recrystallization at room temperature. Whether I

Jan 1, 1951

By Sydney H. Ball

MINERALS used primarily for personal adornment and decorative purposes are called precious stones. To be so prized, the stones must possess beauty of color, must not be too common, and must be hard enough to withstand ordinary wear. If transparent, they must have brilliancy and fire. Almost one hundred minerals have been used as precious stones, the noble gems being the diamond, emerald, ruby, and sapphire; pearls are frequently included by courtesy. These gem stones, however, are sometimes equaled in beauty by fine opals, aquamarines, ourmalines, spinels, chrysoberyls (both cat's-eye and alexandrite), and spodumenes (hiddenite and kunzite). The Greeks, Romans, and medieval Europeans grouped together gem stones according to color and degree of transparency, and only as the niceties of mineralogy began to be known, about a century ago, was it realized how many different minerals have the beauty required of gem stones. Pliny, for example, did not distinguish between rubies and the red varieties of spinel and garnet, although he conjectured that the beryl and emerald were one mineral. GENERAL SURVEY Early man treasured bright colored berries, attractive shells, white teeth of wild animals and brightly colored pebbles, and used them as personal ornaments. In the eastern hemisphere, the earliest stones used were members of the quartz family (100,000 to 75,000 B.C.); then obsidian and amber (50,000 to 25,000 B.C.); the jade minerals, fluorspar and jet (22,000 to 7000 B.C.); turquoise (7000 to 3400 B.C.); lapis lazuli and garnet (prior to 3500 B.C.) ; emerald (2000 to 1800 B.C.) ; sapphire, ruby and diamond (800 to 500 B.C.). Indeed, gem mining is the oldest form of mining, and before any metals were known primitive man recognized about 18 gems and decorative stones. At first he sought them in stream gravels and residual deposits but by 3400 B.C. the turquoise mines of the Sinai Peninsula were operated. This was the world's first important hard-rock mining enterprise. The Afghanistan lapis lazuli mines may

Jan 1, 1949

By H. A. MEGRAW

THE meeting of the A. I. M. E. at Wilkes-Barre, Pa., Sept. 12 to 15, inclusive, celebrated the fiftieth anniversary of the Institute. It was at Wilkes-Barre, in 1871, that the foundation was laid for the great institution that now includes in its roster the greatest names. in mining engineering in every civilized country of the world. The founders of the Institute, with rare prescience, established a common ground upon which all mining engineers, whatever particular branch they might consider most pertinent, could stand securely, assured of a deep-seated interest from their brethren similarly minded in other localities. So wise and clear was the vision of the founders that every engineer connected with mining has found it beneficial, not to say indispensable, to maintain his connection with the Institute and to increase his technical enthusiasm through the medium of the valuable technical publications. The little coterie of 1871 has grown to a strong body of more than 10,000 members in 1921, reflecting the glory of the founders in the record of the accomplishments written on the pages of the fifty years of the

Jan 1, 1921

By W. L. Hill, W. H. Armiger, S. D. Gooch

The physical properties, chemical behavior under thermal treatment, and fertilizer value of fluorine-containing pseudowavellite (hydrous calcium aluminum phosphate) that occurs as phosphate clay admixed with quartz sand in an extensive deposit near Bartow, Fla., were determined by experiments in laboratory, pilot-plant, and greenhouse. When the mineral was heated at 500°C, 80 pct of the phosphorus became citrate soluble. The heated product, however, deteriorates markedly under moist conditions such as obtain in the soil.

Jan 1, 1950

By G. C. Stone

AS the term "hardness" is used with many different meanings, it should be understood that it here means resistance to deformation by compression. It was determined by measuring the pressure, in pounds per square inch, necessary to reduce by 20 per cent., the length of cylinders 1 in. (25 mm.) in diameter by 2.6 in. (66 mm.) long. The tests were made at Columbia University on an Olsen 400,000-lb. machine, the load being applied at a constant rate of speed 0.0319 in. per min. The results were obtained by Messrs. Rigg and Williams, and some of them were given in a paper read at the Sixteenth Annual Meeting of the American Society for Testing Materials, in June, 1913. The remainder of the results were obtained in subsequent experiments by the same authors. In all cases, the results given are the averages of three or more closely concordant tests. All of the spelters tested were of standard commercial grades and all were of compositions making them good deliveries. The accompanying table gives the results arranged in the order of increasing hardness:

Jan 1, 1919

By AIME AIME

LOCAL COMMITTEES. EXECUTIVE.-W. A. Lathrop, Chairman; R. V. Norris, Secretary; S. D. Warriner, Treasurer; Irving A.. Stearns, W. J. Richards, H. S. Drinker, C. D. Simpson. GENERAL RECEPTION.-Irving A. Stearns, Chairman. Archibald, James, Jr., Pottsville. Lawall, E. H., Wilkes-Barre. Ashley, H. H., Wilkes-Barre. Lentz, W. 0., Mauch Chunk. Ayres, WV. S., Hazleton. Lewis, Albert, Bear Creek. Beard, J. T., Scranton. Loomis, W. H., Jeddo. Bridgman, J. C., Wilkes-Barre. Markle, Alvan, Hazleton. Bunting, Douglas, Wilkes-Barre. Markle, John, Jeddo. Chase, F. M., Wilkes-Barre. Neale, J. B., Minersville. Coroner, Eli T., Scranton. Norris, R. V., Wilkes-Barre. Cote, E. B., Jr., Drifton. Oliver, Paul A., Oliver's Mills. Davies, W. H., Hazleton. Owens, W. D., Pittston. Davis, H. G., Dorranceton. Pardee, 1. P., Hazleton. Dodge, W. F., Wilkes-Barre. Quin, R. A., Wilkes-Barre.

Jul 1, 1911

By E. H. Rose

IN these days of the spectacular in research and technological accomplishment, it is easy and natural to overlook some of the applications to everyday life of recent developments of a more pedestrian kind, or to fail to realize that sometimes two or three of the latter may be combined to serve a novel purpose in fields other than those in which they grew. The present remarks are to point out three such developments which might be combined to apply to an everyday function of the A.I.M.E. as an organization. By its Constitution, the A.I.M.E. is organized "to promote the arts and sciences connected with . . . minerals and metals, and the welfare of those employed in these industries . . .; to hold meetings for social intercourse and the reading and discussion of professional papers, and to circulate . . . among its members the information thus obtained . . .; and to . . . maintain . . . a library." By these words of Article I the profession of mining and metallurgy is recognized to involve many arts and sciences, of which the art and science of exchanging information is a leading one. As to methods of preparing or securing papers, the Constitution is silent.

Jan 1, 1944

By C. H. Snyder

Tlie paper deals with details of construction of the Colmol, including improvements in design that will be incorporated in new models. These improvements are results of problems encountered and worked out in experimental operation with the unit. Also included is a descriptive plan of operating where roof and air conditions are of the worst. A summary of production results from the machine is presented. THE various units used in conventional mining are well-built. Generally the universal under -cutter, driven by approximately 50 hp, weighs approximately 25,000 lb, and is a very strong piece of machinery. The drilling machine is not as husky as an undercutter, generally is driven by approximately 15 hp, weighs about 9000 lb, but is a well-constructed, sturdy mechanism. The loader, usually 60 hp, weighs approximately 24,000 lb, and certainly is a strong, rugged unit. The working parts of all three of these sturdy conventional units have been made of tough steel alloys for some time. With the use of three machines having a combined horsepower of approximately 125, with a combined weight of approximately 60,000 lb, and with the possible inherent advantage of single purpose machines performing a single function, the use of considerable explosives has been required to complete the conventional mining cycle. It was therefore our thought, upon conception of the first Colmol,* a machine which was to do the work accomplished by the three conventional units plus explosives, that it must be a rugged mechanism. Now, after building several units, after going through many and varied experiments, and after the expense of some million-odd dollars, we find we have observed and learned nothing that contradicts our original thinking. A continuous miner, if it is to give satisfactory performance, must be a rugged piece of machinery. Ruggedness has been, and is constantly, in the minds of our engineers in designing the Colmol. Improvements where they have been required have been in the direction of more weight, more horse power, better alloys, bigger hydraulic pumps and motors; in short, always, toward more torque, greater strength, more ruggedness. Now not only the finest steel alloys are utilized but more than 100 Timken roller bearings are used. The following is some pertinent data on models being built and to be built: The low unit: Cutting height, 30 to 42 in. By changing the upper gear case the maximum cutting height can be increased to 61 in., giving a variable cutting height of from 30 to 61 in. Width of cut, 9 ft 6 in. Width of body, 75 in. over tracks. Height of body, 271/2 in. Overall length, 23 ft. Driven by three 50-hp motors or a total of 150 hp. Weight, 26 tons. The intermediate unit: Cutting height, 451/2 to 72 in. Width of cut, 9 ft 8 in. Width of body, 77 in. over tracks. Height of body, 43 in. Overall length, 26 ft. Driven by three 70-hp motors or a total of 210 hp. Weight, 35 tons.

Jan 1, 1951