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By Hugh M. Roberts, R. D. Longyear

Introduction ............................ 27 GEnERal Geology........................... 29 The ORebodY in Western Falco~ridgI TownsRip........... 31 Quartzite-Graywacke Formation................... 33 Greenstone............................ 33 Norite ............................. 33 Metamorphism.......................... 35 The Orebody........................... 36 Mineralogy ........................... 37 Grade of Ore........................... 42 Genesis oF tEe Ores . :....................... 43 Summary of Various Hypotheses.................. 44 Magmatic Segregation by Crystallization of Sulphides........ 44 Gravitational Segregation of Molten Sulphides at the Base of the Magma 45 Intrusion of Molten Sulphides after the Consolidation of 'he Nurite.. 45 Deposition by Hydrothermal Solutions.............. 46 Magmatic Segregation by Extraction from Crystallizing Norite... SO The Relationship between the Exploration and Theories of Origin .... 50 Volume Relations of Norite and Sulphides............... 62 Intimate Association of Norite and Sulphides............. 53 Granitic Material........................ 54 Uniform Content........................ 54 Sulphides in Walls......................... 54 Absence of Typical Hydrothermal Minerals.............. 55 SUmmaRY................................ 56 Introduction During 1916 and 1917. the E. J. Longyear Co. of Minneapolis. Minn., carried out a campaign of exploration for nickel-copper ore in the Sudbury District of Ontario. The work was initiated by W. E. Smith. a resident of Sudbury. who called the attention of W. J. Mead. Chief Geologist

Jan 1, 1918

A meeting of the Board of Directors was held in the Council Room of the U. S. Bureau of Mines, Interior Building, Washington, D. C., on Friday, June 21, 1918, at 4 p. m. Twelve members of the Board, the Secretary of the Institute, and nine guests were present. Upon the petition of 28 members of the Institute residing in or near Washington, D. C., a Washington Section was authorized. A committee was appointed to nominate officers and prepare a set of by-laws. The report of the Treasurer was presented in writing, accepted, and ordered filed. Thirty-nine members, 12 associates and 8 junior associates were elected. Two members were reinstated. One resignation was accepted. The dues of 64 members were suspended on account of their being on active war duty.

Jan 8, 1918

By Heber Cole

THE gypsum industry of Canada, like all others connected with the construction business, has felt the full effect of the depression during the past few years, and sales of its products have been greatly curtailed. The year 1934, however, saw a decided turn for the better and a gradual but steady improvement is noticeable in all its branches. In many ways the depression has been a blessing in disguise to the gypsum industry; during the years from 1926 to 1930, demand increased so rapidly that companies were forced to expand and often new apparatus and machinery were placed in operation regardless of expense, or plants already existing were taxed to their limit and forced to keep running with the minimum amount of repairs. The depression, therefore, has really given the industry what might be called a breathing spell, in which it has had time to take stock of its position, to reduce its costs of production, to devote more serious attention to the quality of its products, and to con-solidate its operations into a smooth working whole, which as conditions improve will enable it to meet the demands of the trade with more varied products of a quality hitherto unattained. Progress in the gypsum industry, however, has not been confined to the years of the depression, for some of the greatest advances occurred under the spur of increased demand for its products by the building trade. The purpose of this paper is to review briefly some of the out-standing trends in the development of the gypsum industry in Canada during the past 10 or 12 years.

Jan 1, 1935

By Robert S. Dalzell, Ernest A. Curth

Following the introduction of shields to the U.S. longwall mining scene and the steady increase in the number of shield faces during recent years, the occurrence of longwall -ground-control -associated accidents has shown a welcome downward trend. But even though the accident experience is favorable, problems exist. New mining systems, however efficient, have run afoul of roof control. Shield faces have suffered extended stoppages because of roof cavities. Therefore, the Bureau of Mines has reviewed foreign remedial techniques to evaluate their potential for domestic application. Such technology includes cribbing, strain absorbent modules (SAM'S), inflatables, wire meshing, chemical rock stabilization, synthetic foams, and monolithic fills.

Jan 1, 1984

By J. B. Warriner

Stripping is the name given to the process of removing clay, rock, or other cover from deposits of coal or ore. In this paper it is intended to cover the methods used in carrying on this operation in the anthracite coal regions of Pennsylvania. In doing this, attention will be chiefly devoted to those methods wherein practice in different sections of the region differs, or is susceptible to change or improvement, though it is intended to give as complete data as possible concerning all stages of the operation. The data from which this paper has been prepared have been collected and submitted by a committee† representing the larger users of stripping methods, of which committee the writer has acted as chairman. Data and assistance have also been obtained from various mining men, engineers, contractors and manufacturers of stripping equipment, to all of whom our appreciation is due. Early History and Statistics The earliest mining operation on a commercial scale in the anthracite region was a stripping operation. This was the famous Quarry mine at Summit Hill, where this method was used only because no other method of mining a deposit of the nature found there seemed feasible to the early operators. A description of this stripping from a report published in 1821 is as follows: "The coal mine at present worked by the company lies on the top of a mountain, and appears to extend over some hundred acres of land covered by about 12 ft,. of loose black dirt resembling moist gunpowder, which can be removed by cattle with scrapers, and thrown into the valley below so as never to impede the work. The thickness of the coal is not known, but a shaft has been sunk in it 35 ft. without penetrating through. More than an acre of mine has been uncovered and presents a huge rock of coal, which is easily quarried without blasting."

Jan 1, 1918

By Donald L. Katz, Leo B. Bicher

A correlation is presented for predicting the viscosities of light paraffin hydrocarbon mixtures such as natural gases for temperatures from o° to 4o0°F. and for pressures fro1 atmospheric to I0,000 lb. per sq. in. The correlation is based on the viscosity data for the methane-propane system and requires only a knowledge of the molecular weight of the naturaI gas. The viscosities of natural gases reported in the literature up to 2500 lb. were reproduced by the correlation with an average deviation of 5.8 per cent. Introduction The viscosity of a natural gas is required whenever calculations are made of the pressure drop that occurs while the gas flows through pipes or porous media. Methods of predicting the viscosities of gases at the present operating pressures are not available. This paper presents a simple method of predicting the viscosity of a natural gas in the single-phase region from its molecular weight, temperature, and pressure. Viscosity oF Methane-propane Mixtures The viscosity of methane, propane, and four of their binary mixtures, 20,40, 60, and 80 mol per cent, have been determined for pressures from 400 to 5000 lb. per sq. in. and temperatures from 77" to 437 F., with an experimental accuracy of 3.2 per cent.2 The apparatus used in the investigation was a modification of that employed in previous studiesaJ4 on the viscosity of normal paraffin hydrocarbons. It consists of a viscosimeter of the rolling-ball, inclined-tube type,5>k7 with auxiliary equipment for making up and charging binary mixtures into the viscosimeter.~ The viscosity data on the methane-propane mixtures have been plotted as a function of molecular weight with lines of constant pressure, charts of constant temperature in Figs. I to 3. These charts are extrapolated at temperatures below 77°F. and at pressures above 5000 lb. per sq. inch. Prediction OF Viscosity from Molecular Weight of a NaturaI. Gas At atmospheric pressure the viscosity of light hydrocarbon gases increased with increased temperature, contrary to the change of viscosity of liquids with temperature. The atmospheric viscosities of the normal paraffin hydrocarbons have been determincd by several investiga-tors 3,4,9,10,12,15,16,17,19 and are plotted in Fig. 4 as a function of molecular weight, with extrapolation to 896'F. and to 220 molecular weight. Data for isopentane and normal pentane show less than 2 per cent difference in viscosity, indicating that Fig. 4 can be used for isomeric parafin hydrocarbons with an accuracy of approximately 2 per cent. Trautz and Sorg'7 determined the atmospheric viscosities 01 methane-propane mixtures and showed that they are proportional to the molecular weight. The viscosities of these mixtures

Jan 1, 1944

By Leo B. Bicher, Donald L. Katz

A correlation is presented for predicting the viscosities of light paraffin hydrocarbon mixtures such as natural gases for temperatures from o° to 4o0°F. and for pressures fro1 atmospheric to I0,000 lb. per sq. in. The correlation is based on the viscosity data for the methane-propane system and requires only a knowledge of the molecular weight of the naturaI gas. The viscosities of natural gases reported in the literature up to 2500 lb. were reproduced by the correlation with an average deviation of 5.8 per cent. Introduction The viscosity of a natural gas is required whenever calculations are made of the pressure drop that occurs while the gas flows through pipes or porous media. Methods of predicting the viscosities of gases at the present operating pressures are not available. This paper presents a simple method of predicting the viscosity of a natural gas in the single-phase region from its molecular weight, temperature, and pressure. Viscosity oF Methane-propane Mixtures The viscosity of methane, propane, and four of their binary mixtures, 20,40, 60, and 80 mol per cent, have been determined for pressures from 400 to 5000 lb. per sq. in. and temperatures from 77" to 437 F., with an experimental accuracy of 3.2 per cent.2 The apparatus used in the investigation was a modification of that employed in previous studiesaJ4 on the viscosity of normal paraffin hydrocarbons. It consists of a viscosimeter of the rolling-ball, inclined-tube type,5>k7 with auxiliary equipment for making up and charging binary mixtures into the viscosimeter.~ The viscosity data on the methane-propane mixtures have been plotted as a function of molecular weight with lines of constant pressure, charts of constant temperature in Figs. I to 3. These charts are extrapolated at temperatures below 77°F. and at pressures above 5000 lb. per sq. inch. Prediction OF Viscosity from Molecular Weight of a NaturaI. Gas At atmospheric pressure the viscosity of light hydrocarbon gases increased with increased temperature, contrary to the change of viscosity of liquids with temperature. The atmospheric viscosities of the normal paraffin hydrocarbons have been determincd by several investiga-tors 3,4,9,10,12,15,16,17,19 and are plotted in Fig. 4 as a function of molecular weight, with extrapolation to 896'F. and to 220 molecular weight. Data for isopentane and normal pentane show less than 2 per cent difference in viscosity, indicating that Fig. 4 can be used for isomeric parafin hydrocarbons with an accuracy of approximately 2 per cent. Trautz and Sorg'7 determined the atmospheric viscosities 01 methane-propane mixtures and showed that they are proportional to the molecular weight. The viscosities of these mixtures

Jan 1, 1944

By M. V. Lowry

This paper outlines the economic considerations that led to the recent installation of a thickener at St. Joseph LeadCo.'s Balmat, N.Y. mill. To incorporate storage of concentrates, they decided upon a single, unusually deep tank to be used for both storage and thickening. The abnormally high rake lift required was achieved by the novel feature of having the entire drive platform raise and lower. Initial operating problems are described along with the satisfactory solutions. Total costs for concentrate handling before and after installation of the storage thickeners are compared. In Northern New York State, the St. Joseph Lead Co. conducts a 2100 tpd zinc mining and milling operation at its Balmat Plant. Conventional crushing, grinding, and flotation is used to produce a zinc concentrate. For 32 years, from 1930 through 1962, the plant operated with the concentrates going directly from flotation to the filtering, drying, and loading facilities. All of the concentrate handling equipment, therefore, had to operate 24 hrs per day. It also had to accommodate wide fluctuations in tonnage, due to variations in the grade of ore. Many problems were thereby encountered in filtering and drying, but it was never concluded that the cost could be justified for installing a conventional, large diameter thickener. Finally, in 1963, they installed an unconventional thickener that is unusual in several respects. The tank depth is 16 ft instead of the normal 8 ft. The rakes are raised and lowered by having the main drive gear located on a movable platform. Automatic controls are programmed to raise the drive platform and rakes during one shift of storage. During the next two shifts of withdrawal, the controls are programmed to lower the drive platform and rakes. After three years of operating this unique storage-thickener, the conclusion is that a correct choice was made from several alternative schemes for storing concentrates. The various considerations involved in the final selection will here be analyzed, and the design features and installation details will be de- scribed. Operating problems and modifications made to the equipment will next be considered, and finally the effects upon filtering, drying, and loading will be reported. SELECTION CONSIDERATIONS Even without a thickener, concentrate handling had become reasonably efficient at the Balmat Mill by the year 1962. A tonnage that varied between 6 and 25 tph was being handled fairly satisfactorily. The filter cake moisture of 8%% seemed quite respectable, except that two large filters were usually in service. Three filters often had to be operated in order to prevent excessive filter overflow with consequent loss of values. This situation occurred when zinc concentrates from flotation exceeded 20 tph and when filter cloth blinding developed. Over the years, numerous small improvements had been effected, such as: selection of a filter cloth with better flow characteristics; addition of flocculant to the filter feed; and, in 1953, the smallest of three drum filters was replaced by a five disc, 8' 10" diam filter with a bottom agitator and snap blow. As another example of fairly efficient operation, the oil-fired dryer was doing a seemingly satisfactory job of further reducing the moisture content to an average of 3%. However, there were often considerable dust losses when the tonnage suddenly dropped off to 6 tph. At high tonnage rates, the resulting high moistures of 4% and 5% caused difficulties due to concentrates sticking and freezing in chutes leading to the box car loaders. (Drying of concentrates is justified because of the high freight rate for the long shipping distance to the company owned smelter at Josephtown, Pa. near Pittsburgh.) It was long realized that installation of a thickener would permit the subsequent steps of concentrate handling to proceed more smoothly and would alleviate the problems existing in the filtering, drying, and loading operations. It was also realized that even a slightly lower filter cake moisture could mean considerable savings in fuel oil. However, all these factors were never quite sufficient to warrant the expense of a thickener until three more considerations were added to the picture. First, the advent of flocculants meant that a thickener of relatively small area could now be considered. Secondly, a complete renovation of the zinc flotation circuit was made between 1957 and 1961. The

Jan 1, 1967

By George K. Burgess

The suggestion has often been made that it would be highly desirable, at least for certain grades of steel, to be able to control more certainly, by pyrometric measurement or otherwise, the temperatures of the operation of the open-hearth and other furnaces used in the manufacture of steel and iron. That the properties of the ingot and finally of the finished steel product are intimately related to the final temperatures attained by the metal in the furnace and to the temperature of casting, has been recognized by metallurgists for a long time, and this question has been very thoroughly treated, especially by Prof. Henry M. Howe, and by A. W. and H. Brearley.1 It is the object of this paper to demonstrate that in so far as casting temperatures of furnaces, steel ingots, and similar operations involving the temperatures of streams of iron and steel are concerned, well-known pyrometric methods may be easily applied—if certain recently determined corrections are made and precautions taken—with a relatively high degree of accuracy. Greater but not insurmountable difficulties will be encountered in the case of open-hearth furnace temperatures, while for those of the converter type a ready solution does not seem practicable. It appears that certain essential data have always been lacking in reporting observations such as those of Le Chatelier in 1892. Thus the correction to be applied for the characteristic radiation—or emissivity— has hitherto not been adequately taken into account nor the limitations of the several possible pyrometric methods clearly recognized. In view of the fact that in open-hearth practice the temperature to be measured in the furnace itself, in the stream of metal and slag and in the teeming into molds or ingots is usually above 1,500" C. (2,700" F.)

Jan 1, 1917

By Lester Uren

Beginning with theoretical concepts of oil drainage, this paper demonstrates that the flow of petroleum into a well from a stratum of oil-saturated sand of uniform texture increases with the diameter of the well. This conclusion is supported by experimental evidence. It appears that if a well may be reamed to a diameter of 20 ft. within the oil sand, its production will be approximately doubled. A novel method is proposed for forming and supporting a cavity of such proportions within the oil-producing stratum. PETROLEUM occurs, in nature, as a fluid saturating the pore spaces between the grains of porous rocks or aggregations of rock particles such as sand, sandstone, conglomerate, shale, limestone, etc. The oil, under the influence of gas pressure, hydrostatic pressure, gravity, earth pressure, and, perhaps, other natural forces, is caused to flow through the porous "reservoir rock" into wells penetrating the stratum in which the oil occurs. The principal moving force is the pressure of dissolved or occluded natural gas within the oil, though this;, force is assisted by gravity and by the hydrostatic or buoyant pressure of ground water about the edges of the "pool." The wells, providing outlets to the surface, are centers of reduced pressure and the flow of rock fluids into a particular well is usually an expression of the difference in pressure existing between the space within the well and that of the stored oil .within the reservoir rock. The greater this differential pressure, the more rapidly will oil flow from the source rock into the well. Opposing movement of the oil from the reservoir rock into the well are certain natural forces related to the rock structure, such as pore friction and capillarity, and certain others related to the physical properties of the oil, such as viscosity and adhesion. The differential pressure between the well and the boundaries of the area drained by it must be sufficient to overcome the forces opposing flow if there is to be movement of oil into the well. If by any device the resistance to movement of the oil may be reduced, the oil will flow into the well at a more rapid rate and the effective area of drainage will be increased.

Jan 10, 1924

By George B. Lee

DURING The Two Years In Which The New Reduction-Works Of The Copper Queen Consolidated Mining Co. Have Been In Operation At Douglas, Ariz., There Has Developed A Remarkable Condition In Regard To The Corrosive Action Of The Water Used To Cool The Jackets Of The Blast-Furnaces. Were It Not For The Many Contradictory Features, It Might Pass As One Of The Unavoidable Troubles Due To The Composition Of The Water. This Water, Obtained From Wells 600 Ft. Deep, Is Also Used In The Steam-Boilers, And Its Composition, As Shown By The Following Analysis, Does Not Indicate The Presence Of Any Ingredient Which Would Explain The Corrosion Grains Per U. S. Gal. Silica, 0.861 Iron Oxide And Alumina, 0.223 Calcium Carbonate, 0.2111 Calcium Sulphate, Magnesium Carbonate, Sodium And Potassium Sulphates, . 14.850 Sodium And Potassium Chlorides, 9.732 Sodium And Potassium Carbonate, 6.452 32.409 The Jackets Are Made Of Inner Plates 0.5 In. Thick And An Outer Plate I In. Thick, With 3-In. Stiffeners Between The Inner And Outer Plates. In From 10 To 12 Months The Inner Plates Have Been Reduced By Corrosion To A Thickness Of From 1/8 To 1/16 In., While The Outer Plate In The Same Time Is Reduced By Less Than 1/16 In., And The Stiffeners Show Very Little Corrosion. The Plates Are Pitted And Eaten Away In Some Places More Than In Others. There Is Practically No Scale Found On The Jackets, But When Cleaned Considerable Iron Oxide Is Found In The Bottoms. With An Action So Marked, Serious Trouble Would Be Expected In The Boilers, But, On The Contrary, A Recent Inspection By a

Mar 1, 1908

By John T. Eash, Clair Upthegrove

During recent years nickel has had an increasingly important role as an alloying element in the copper-tin bronzes. Nickel additions not only produce better casting alloys but also make alloys whose properties can be varied by precipitation hardening; thus leading to increased commercial application of copper-nickel-tin alloys. Recent investigations have indicated a decrease in the solubility of tin in the alpha phase as the annealing temperature is lowered and as the nickel content is increased within certain limits. A further change caused by the nickel additions is produced in the excess phase of the copper-tin bronzes. The alpha plus delta eutectoid is replaced by a clear precipitated constituent in the alloys containing up to 15 per cent tin and not less than 1 per cent nickel. This paper has a dual purpose. The first is to present a new determination of the alpha-phase boundary in alloys containing from 0 to 20 per cent nickel, together with the liquidus and solidus temperatures above that field. The second purpose is to give the equilibrium conditions existing in alloys exceeding the alpha phase containing up to 31 per cent tin and 5 per cent nickel, so that the disappearance of the alpha plus delta eutectoid constituent may be explained. After considering the earlier investigations of the related alloy systems and the experimental procedure used in this investigation, the alloys will be discussed in groups as separate quasibinary systems containing constant amounts of nickel. The systems considered contain 0, 1, 2, 3, 5, 10 and 20 per cent nickel. The straight copper-tin system was reinvesti-gated in order to establish a foundation on which to build the remaining material. The 1 per cent nickel alloys studied give the relations existing in the region of the eutectoid transformation between the copper-tin system and the 2 per cent nickel copper-tin system which has been investigated in detail. The thorough examination of the latter system was made since 2 per cent of nickel is representative of the commercial additions to the cast bronzes and also because it is sufficient to produce

Jan 1, 1933

CONTENTS PAGE. WHITE, DAVID.-Environmental Conditions of Deposition of Coal. Discussed by E. C. Jeffrey, George H. Ashley, Reinhardt Thiessen, S. W. Parr, David B. Reger, Wilbur A. Nelson, James F. Kemp, E. S. Moore, Homer G. Turner, David White, A. C. Noé, W. A. I. M. van Waterschoot van der Gracht 2 THIESSEN, REINHARDT.-The Constitution of Coal. Discussed by Edward C. Jeffrey, Reinhardt Thiessen, Ralph H. Sweetser, David White 12 TURNER, HOMER G.-Microscopical Structure of Anthracite. Discussed by E. S. Moore, Edward C. Jeffrey, Reinhardt Thiessen, H. J. Rose, James F. Kemp, David White, Clarence A. Seyler, A. C. Noé 14 JEFFREY, EDWARD C.-Coal in Relation to Coke. Discussed by H. J. Rose, David White, E. S. Sinkinson, S. W. Parr, James F. Kemp, Edward C. Jeffrey, Reinhardt Thiessen, Chas. R. Fettke 17 FRANCIS, W., and WHEELER, R. V.-The Resolution of Coal by Oxidation. Discussed by Edward C. Jeffrey, S. W. Parr, E. S. Sinkinson, Reinhardt Thiessen, David White 23 TIDESWELL, F. V., and WHEELER, R. V.-The Constitution of Coal. Discussed by David White, A. C. Fieldner 24 JOLLY, J., and WHEELER, R. V.-Organic Sulfur Compounds in Coal. Discussed by S. W. Parr 25 SINNATT, F. S.-Selective Combustion in Coal. Discussed by J. D. Davis, A. C. Fieldner, Geo. S. Rice, W. M. Grant, H. J. Rose, S. W. Parr, David White 25 COBB, JOHN W.-Nitrogenous Constituents of Coal. Discussed by S. W. Parr, H. J. Rose, Reinhardt Thiessen 28 PARR, S. W., and HOBART, F. B.-Coal and Oxygen. Discussed by J. D. Davis, W. T. Thorm, Jr., S. W. Parr, H. J. Rose, A. C. Fieldner, F. F. Jorgensen, David White, W. M. Grant 30 FIELDNER, A. C., and DAVIS, J. D.-Modern Views of Chemistry of Coals of Different Ranks as Conglomerates. Discussed by S. W. Parr, David White, Reinhardt Thiessen, A. C. Fieldner, Clarence A. Seyler 32 EBY, J. BRIAN.-Contact Metamorphism of Some Colorado Coals. Discussed by Geo. C. McFarlane, W. T. Thom, Jr 35 WHITE, DAVID.-Progressive Regional Carbonization of Coals. Discussed by A. C. Fieldner, Homer G. Turner, W. A. J. M. van Waterschoot van der Gracht, A. C. Noé 37 THOM, W. T., JR.-Moisture as a Component of the Volatile Matter of Coal. Discussed by A. C. Fieldner, S. W. Parr, Clarence A. Seyler, W. T. Thom, Jr., R. D. Hall 39

Jan 7, 1925

By Charles Hart

THE art of electric smelting came with the turn of the present century and owes its existence to the introduction of alter-nating current, which found its first wide use in the establishment of the great power plants at Niagara Falls, N, Y. Prior to that time current was largely direct. The fur-naces were electrolytic in nature and found their first metallurgical use in the produc-tion of aluminum, and this process still prevails. The normal production of pig iron up to that time was carried on in blast furnaces in which charcoal, coke and anthracite were used as the fuel. This new electric process called for sufficient carbonaceous material to reduce the oxides and impregnate the pig iron with sufficient carbon, but the remainder of the energy was to be supplied by electric power. The chemical reactions are essentially the same in electric smelting as obtains in the older blast furnace. All of these data are so well known in both methods as to need no discussion at this time, for they can be found in scientific publications and books written during the first two decades of this century.

Jan 1, 1940

By Ralph E. Davis, Lyon F. Terry

The rapid expansion of the natural gas industry in this country during the past three or four years has necessitated the construction of a number of long and comparatively large diameter high-pressure pipe lines This period of expansion and construction is still at high tide, and the current year will doubtless surpass all prior years in mileage and capacity of gas line installation. The fundamental economics of the business of long-distsrier transportation of natural gas may be briefly and simply stated, although most careful consideration must be given the actual determination and integration of the several more important factors which determine the ultimate success or failure of such a project. Reduced to its simplest form, a sound natural gas transportation project requires: 1. A competent source of gas, where the combination of quantity of gas available, cost of production, and longevity meet the given requirements. 2. A market, reasonably certain to endure in the face of any probable competition, of satisfactory size and price, and having a sufficiently favorable load factor. 3. A cost of installation of pipe line systen and an operating cost such as will, with honest and reasonably efficient management, afford a net operating return sufficient to attract the necessary capital required. In a11 new projects of this kind it is necessary that thehe three cssentials to ultimate success be assured. Hence the necessity of competent surveys of gas supply, and of market, both industrial and domestic. The prudent engineer will allow for "factors of safety" in reaching his conclusions just as he would in the design of a bridge. This paper deals primarily with but one of the major considerations enumerated above, I. e, the economic design of the pipe line system. The "pipe line system" will be considered to include (1) the pipe Iine, and (2) a series of compressor plants along the pipe line for maintaining

Jan 1, 1929

By J. L. W. Birkinbine

This paper is a discussion of a part of the mineral wealth of the States of Oaxaca and Paebla, Mexico. It does not refer to the precious metals, sonie mines of which, in these States, are said to have been worked before the advent of the Spanish conquistadores in the sixteenth century, as my purpose is to invite attention to the exploration of deposits of coal and iron-ores in the Mixteca region. The prominence given to coal is warranted by the great effect of the scarcity of fuel upon the industrial development of Mexico. Under the progressive administration of President Porfirio Diaz, the Republic has made wonderful advances in the past three decades; and this progress would have been greater but for the limitations imposed by expensive fuel. In the spring of 1906 I was detailed by the Birkinbine Engineering Offices, of Philadelphia, to accompany A. B. Adams, of New York, in a reconnoissance of reported deposits of iron-ores in the State of Oaxaca. The result of this expedition was the formation, in 1907, of the Oaxaca Iron & Coal Co., of which Mr. Adams became, and has remained, President and General Manager, and I have spent the past three years as Chief Engineer of this company in Mexico, principally in western Oaxaca, where field-headquarters were established. GEOGRAPHY AND POPULATION. Although the geographical and topographical features of the Republic of Mexico are well known, few realize that the majority of its population is domiciled in the States which immediately surround the capital city of Mexico, including the Federal District, Mexico, Tlaxcala, Morelos, Puebla,

Jan 1, 1911

By AIME AIME

Report of Committee 24, of the International Association for Testing Materials, presented at the Brussels Congress, 1906. Republished for use at the 94th Meeting of the American Institute of Mining Engineers, New York, N. Y., February, 1908. Discussion by letter is requested by the Secretary of the Institute. The Committee appointed for the solution of Problem 24 consisted of the following members Prof. H. M. Howe, New York, N. Y. (Chairman); L. Levy, Paris, France (Vice-Chairman) ; Prof. D. Tschernoff, St. Petersburg, Russia (Vice-Chairman) ; Prof. Albert Sauveur, Cambridge, Mass. (Secretary) ; Van Drunen, Ixelles, Belgium; Lieut.-Col. H. Tusen, Copenhagen, Denmark ; E. P. Martin, Abergavenny, England ; A. Pourcel, Paris, France ; H. Brauer, Dortmund, Germany ; Dr. Prof. H. Wedding, Berlin, Germany; P. Verole, Milan, Italy ; A. Baalsrud, Christiania, Norway ; A. R. v. Dormus, Vienna, Austria ; A. Sailler, Vienna, Austria; Bureau des Forges, St. Petersburg, Russia; Prof. N. Belelub-sky, St. Petersburg, Russia ; N. Jossa, St. Petersburg, Russia ; Maj.-Gen. M. Korobkoff, St. Petersburg, Russia ; S. Smirnoff, St. Petersburg, Russia ;.Ladislaus v. Tetmajer, Budapest, Hungary ; H. H. Campbell, Steelton, Pa. Early in February, 1905, a list of species and varieties of iron and steel, with definitions, drawn by the Chairman and Secretary of Committee 24, was sent to every member of this Committee with a request for comments and suggestions. A special request was sent to the following gentlemen . for the equivalents in their several languages of these species and varieties : A. , Pourcel, Paris, France; Prof. H. Wedding, Berlin, Germany ; J. A. Brinell, Stockholm, Sweden ; Prof. H. I. Hannover, Copenhagen, Denmark; Prof. P. Kley, Delft, Holland; P. Verole, Milan, Italy; Col. Cubillo, Trubia, Spain. This present report, which is based upon our original list and definitions, and upon the replies to these requests, consists of four parts I. A polyglot, which gives the names of the chief classes of iron and steel in English, French, German, Swedish, Danish and Dutch. We .regret that we have failed to get the Italian and Spanish names. II. English definitions of principal classes of iron and steel. III. A glossary of special sizes and shapes of iron and steel. IV. A note on the boundary between steel and cast-iron. I. POLYGLOT, IN ENGLISH, FRENCH, GERMAN, SWEDISH, DANISH AND DUTCH, OF THE CHIEF CLASSES OF IRON AND STEEL, AND OF THE APPARATUS IN WHICH THEY ARE MADE. This list is not intended to be complete, but rather to include only those varieties which are of interest to the Association.

Mar 1, 1908

By Robert C. Berggan

The hot-milling process for reconditioning rock-drill bits is not new. It has been employed by a few mines for years and in the past decade it has been widely adopted, as its advantages have become better known. Because of the extensive commercial development in England and Canada of machines to operate on this principle, general acceptance has been largely in the British possessions and until recently has been chiefly in the field of conventional steel. In the past two years there has been a definite trend toward hot-milling of detachable bits in Canada, but only in the past year has any considerable attempt been made to build special machines for this type of work. Generally a machine designed for conventional steel has been used and special holders employed to manipulate the bit. As early as 1934 at least one operator in the United States had adapted hot-milling to conventional steel with a substantial saving in resharpening costs.1 Several other operators have taken it up but there has been no widespread adoption of the method in this country by users of conventional steel. This may be partly explained by the fact that until recently no American manufacturer produced this equipment and operators have been obliged to build their own hot-millers or import them. Several years ago a few machines were built in Seattle, Washington, and operated in some mines in the northwest, but, for reasons not generally known, the effort was abandoned. The Process Hot-milling performs the function of re-dressing the bit at a forging temperature of about 1650°F., by the removal of metal from the flutes with a milling cutter, followed by a similar cut from the bit gauge. Conventional bits are thus treated following the usual forging operation in a sharpener, and usually in the same heat.

Jan 1, 1940

By Robert C. Berggan

The hot-milling process for reconditioning rock-drill bits is not new. It has been employed by a few mines for years and in the past decade it has been widely adopted, as its advantages have become better known. Because of the extensive commercial development in England and Canada of machines to operate on this principle, general acceptance has been largely in the British possessions and until recently has been chiefly in the field of conventional steel. In the past two years there has been a definite trend toward hot-milling of detachable bits in Canada, but only in the past year has any considerable attempt been made to build special machines for this type of work. Generally a machine designed for conventional steel has been used and special holders employed to manipulate the bit. As early as 1934 at least one operator in the United States had adapted hot-milling to conventional steel with a substantial saving in resharpening costs.1 Several other operators have taken it up but there has been no widespread adoption of the method in this country by users of conventional steel. This may be partly explained by the fact that until recently no American manufacturer produced this equipment and operators have been obliged to build their own hot-millers or import them. Several years ago a few machines were built in Seattle, Washington, and operated in some mines in the northwest, but, for reasons not generally known, the effort was abandoned. The Process Hot-milling performs the function of re-dressing the bit at a forging temperature of about 1650°F., by the removal of metal from the flutes with a milling cutter, followed by a similar cut from the bit gauge. Conventional bits are thus treated following the usual forging operation in a sharpener, and usually in the same heat.

Jan 1, 1940

By AIME AIME

MEXICO embraces one of the great metal and petroleum producing provinces of the world. In this respect its history dates back to the overthrow of the Aztec empire by a Spanish force under Hernando Cortes between 1519 and 1.521. Even before then, its richness in silver and other minerals was not unknown. But it was a treasure house for the Spanish conquerors until the country became independent in 1821. It has been computed that in the 400 years following 1521, Mexico yielded 1.55,000 metric tons of silver, worth $3,000,000,000, two-thirds of the entire world production. In 1935 the country accounted for 36 per cent of the world's silver output, 14 per cent of its antimony (in 1934), 13 per cent of its lead, 3 per cent of its zinc and copper, and 21/2 per cent of its petroleum. Contrary to the impression of some, its gold output is now comparatively small, though important in the past. Its oil, as well, formerly hulked much larger than now, in 1921 being one-fourth of the world output.

Jan 1, 1936