Search Documents

By Wilbert McBride

Two Alco 3 ½ -ton motor trucks were used by Young Bros. while operating at the Mammoth Collins mine at Shultz, Ariz. One was equipped with an oil tank holding 1,075 gal. and was used for the transportation of "tops." The, other was fitted with a stake body and used to carry machinery, wood, rails, pipe and all classes of miscellaneous supplies. The bodies were made of oak with maple flooring and were attached to the frame of the chassis by U-bolts, to avoid drilling the main members of the frame. Most of the hauling was done from Tucson, a distance of 47;2 miles. During the first. 3 months, part of the road was in very bad condition and the tire cost was excessive. After this part was repaired the road was in fair condition, but never good. There were no excessive grades or bad sand, but wagon ruts, too narrow for the truck wheels and of a different gage, caused heavy tire loss; while chuck holes, sharp curves and stones, both imbedded and loose, were objectionable features. During wet weather the trucks could not get sufficient traction to climb some of the hills and were likely to stick in the mud in certain places, so that no attempt was made to run them unless they were on the road when the rain started. This lost time amounted to about 5 per cent. of the total, but, whenever possible, it was utilized in making minor repairs. The price of gasoline, was from 17 to 21 c. per gal. Rubber tires were used throughout. Drivers were paid $4.50 to $5 per shift, and a return trip to Tucson was counted as two shifts even when made in one day. Drivers were provided with a room in Tucson and were paid for all time lost due to causes beyond their control. Trucks were loaded one way only.

Jan 7, 1916

By N. M. Langdon

ON account of its greater economy and cleanliness, and the extent to which iuferior fuels can be utilized for its generation, there has been of late a rapidly increasing tendency to substitute gaseous for solid fuel for metallurgical and other industrial purposes, which has led to various improvements both in the process and apparatus for its manufacture, notably among which may IN mentioned the Tessie Gas Producer* described by Mr. A. L. Holley. A considerable experience by the author with producers of various kinds using anthracite fuel, in connection with the Taylor ore-roast ing furnace at Chester, N. J., with more or less unsatisfactory resnlts, finally led to the erection of the experimental producer described below, which combines in its construction, simplicity, dorability, and accessibility for cleaning and removing the ash and manipulating the fuel. It is adapted to the use of various kinds of fuel, and is capa ble of generating a steady and uniform supply of gas at a minimum cost. It has been in constant use day and night for about five months, and has given very satisfactory results. The producer, as shown in the accompanying sketch, consists of a cylindrieal furnace, preferably inclosed in an iron jacket or casing, having a bosh or inverted cone-shaped base as in a blast furnace. It is provided with a bell and hopper, the bell being hung to a forked lever, and having guide flanges to prevent it from swing ing, and an opening at its apex through which to insert a bar for manipulating the fuel, which when not in use is closed with a plug or stopper. Cleaning is effected through two small doors placed opposite each other at the hearth level, which in order to facilitate the operation is elevated above the floor. The doors are removable, and when closed are by their own weight and by means of bevelled lugs held tightly against their frames, forming a practically tight joint. A blast of commingled steam and air is injected into the fuel through a series of tuyeres underneath the bosh communicating with steam jet injectors. A small flue also connects the door

Jan 1, 1884

By Thomas M. Drown

IN the course of some experiments on the analysis of pig iron, I heated, in a platinum crucible, some borings of a graphitic pig iron with sodium carbonate. When the crucible was at a full red heat and the carbonate was thoroughly fused, I noticed a lively ebullition of the mass, and an escape of gas, which burned on the surface. On investigation this gas proved to be carbonic oxide, and on examining the borings in the bottom of the crucible after an hour or two, they were found to be perfectly malleable, although unchanged in general form and appearance. Analysis showed that the carbon was completely removed. I then repeated the experiment, to ascertain whether the silicon and phosphorus were affected, and found that these elements too were largely removed, and could be found in the fused mass as alkaline silicates and phosphates. In order to ascertain whether the removal of the silicon and phosphorus was merely a surface action or whether the reaction really extended into the mass of the iron, I tried the following experiments : A number of bars of pig iron were cast about one foot long and planed down-accurately to one inch section. These were immersed in a large wrought-iron pot full of molten sodium carbonate made by fusing the commercial bicarbonate of soda. Through the kindness of Mr. Frank Firmstone, Superintendent of the Glendon Iron Works, Easton, I was enabled to keep this pot at a reasonably constant high temperature for a long time in one of the hot-blast ovens. One of the bars was removed from the pot every twenty-four or forty-eight hours, according to the rapidity of the action, and after cooling was broken and the fracture examined. The change from pig iron to malleable iron was progressively inwards and always sharp and easily recognized, the rate of progression being in a decreasing ratio with the time. The temperature of the oven had evidently

Jan 1, 1879

By F. J. Longworth

For a number of years an intensive study has been made to improve the blast-furnace practice at Copperhill not only as to costs but to provide a good grade of gas for the acid plants. This study, took us back to the fundamentals of successful pyrite smelting; namely, a blast furnace working on a clean sulfide ore, free from fines, and the use of quartz high in silica as a flux. In 1919, the quality of the flux was improved and its effect on the metallurgy was very marked. To improve the practice further, it was necessary to work out some method of treatment for the sulfide fines and the siliceous and refractory ores, other than in the blast furnace. A series of milling tests indicated that these products could be successfully treated by differential flotation, and in 1922 plans were made and a flotation plant built. It was estimated that the flotation plant would deliver to the smelter 40 to 50 tons of concentrates per day; the problem was what to do with these concentrates. It was out of the question to attempt to smelt them in a blast furnace because of the dust losses and, because our practice demands a charge free from fines for satisfactory operation. There is no custom smelter in the vicinity to which concentrates may be sold, pending the time when the tonnage will be sufficient to warrant roasters and a reverbatory furnace. Sintering and nodulizing were investigated but neither method fitted into our scheme of metallurgy. A close study of the converter practice was then made to see if some method could not be evolved to smelt this tonnage of concentrates in a converter without preliminary treatment. At that time, the converter installation consisted of two 12-ft. Great Falls converters, which were handling 12 to 14 per cent. matte. The heat balance of the converters working with 12 to 14 per cent. matte was more than sufficient to smelt the contemplated tonnage of concentrates but the mechanical difficulties. of feeding fines into the Great Falls converter made the use of this type of converter impractical.

Jan 9, 1924

PRIOR to the World War most of the barite used in the United States for manufacturing lithopone and barium chemicals was imported. Germany, by virtue of an abundance of high-grade ore and low labor costs, was in a position to dominate the world market. With the cessa-tion of imports and with the war demand for barium chemicals, the barium chemical industry and the mining of barite became well estab-lished in the United States. This industry has continued to expand because of the increasing use of lithopone. In 1914 the sales of domestic crude barite was 52,919 tons and in 1934 it was 209,850 tons. Barite deposits of economic importance occur in at least 20 states, but the principal producers in 1934 were Missouri, Georgia, Tennessee, South Carolina, Virginia, California and Arizona. The main mining centers are located near the crude barite markets of the three principal marketing districts-the Pacific Coast, the Midwestern area, and the Eastern area. The Pacific Coast is supplied entirely by California, Nevada, and Arizona. The Midwestern area uses most of the Missouri crude and a small amount from the southern states. The eastern market is the chief competitive area. Practically all of the imported crude is marketed there; also the bulk of the southern crude and ground barite. In addition, this area absorbs a small part of the Missouri crude and 80 per cent of the ground barite. Besides the advantage of low delivered costs and purity of product, the imported barite has commanded a price differential because it is soft rather than hard, like many of the domestic ores. The inherent physical properties of the southern ores remain, but the purity can be controlled to a great extent by beneficiation. Simple washing or gravity concentra-tion has sufficed in the past, but in many cases a more efficient process now becomes imperative to remove impurities not amenable to these methods. Certain deposits now being opened are of lower grade and require more precise milling conditions. In some ores, the kind of impurities has changed as the mining advanced.

Jan 1, 1936

By Charles S. Barrett, Robert F. Mehl

It is generally understood by workers in the field of the crystal structure of metallic alloys that terminal solid solutions are of two types, the substitutional and the interstitial. In reviewing the literature, the work of Weissl on the crystal structure of the alpha copper-tin alloys was encountered, in which a new type of terminal solid solution was proposed. In brief, Weiss' findings showed that the density of the alloys calculated from the side of the unit face-centered cube on the assumption of simple substitution—that is, with four atoms to the unit face-centered cell—was much higher than the density measured directly. It was suggested that the assumption of four atoms to the unit cube is not valid for these alloys, and that each unit cube contained less than four atoms; in other words, that one tin atom replaces more than one copper atom, leaving some atomic positions unoccupied. Such a structure, if verified, would have far-reaching significance in the study of the crystal structure of metallic alloys. It would indicate a complexity in terminal solid solutions not hitherto suspected and might encourage work leading to the discovery of other alloys of the same type, and perhaps to types intermediate between it and the two recognized types. It is of importance, therefore, to reinvestigate these alloys with respect to the type of solid-solution structure obtaining therein. Materials and Experimental Method The alloys were prepared from electrolytic copper cut directly from the cathode and the high-purity tin furnished by the U. S. Bureau of Standards for the calibration of thermocouples. No analyses for impurities of these materials or of the finished alloys were made, since such impurities as might be present could have only a wholly inappreciable effect upon the data obtained and the conclusions drawn. The alloys were made by melting the weighed copper charge in a graphite crucible under a KCl-LiC1 flux with later additions of NaC1, using induction heating. When the copper was melted the weighed portions of tin were

Jan 1, 1930

By N. Nakanishi, C. M. Wayman

The effect of small copper additions on the mar-tensitic transformation behavior in Au-47.5 at. pct Cd was studied by measuring electrical resistivity as a function of temperature. The transformation behavior was found to change and transformation start (M,) temperatures for both the ß to ß' and ß to ß' transformations were depressed substantially by the addition of small amounts of copper. Both M, temperatures were lowered approximately 70°C per at. pct Cu. Copper also had the effect of narrowing the transformation hysteresis region (resistivity us temperature), and for the alloy Au-47.5 Cd-1.5 Cu there was little or no hysteresis; in this alloy, the reverse transfmmation upon heating apparently occurs below the thermodynamic equilibrium temperature, To. THE ß phase in the Au-Cd system occurs at the electron/atom ratio 3/2, and is similar to other ß phases in alloys based on copper, silver, or gold. It is of the CsCl type, in which a considerable degree of long-range order persists to the melting temperature.' The phase boundaries of the ß phase are not known precisely below 300° C, but at room tem- perature the phase exists from approximately 46 to 52* at. pct Cd.2 At low temperatures, the ß phase transforms in a diffusionless (martensitic) manner. Alloys having a composition near 47.5 pct Cd transform upon slow cooling to an orthorhombic3 phase, ß', at - 60°C. Alloys having a composition near 49.0 pct Cd, transform at - 30°C into a phase, ß", which has been recently identified as trigonal.4 Alloys having compositions near 48.5 pct Cd will transform into both the 0' and 0" phases over a range of temperatures. The progress of transformations can be observed

Jan 1, 1963

By J. B. Umpleby

The subject of reservoir energy and its efficient utilization has been well explored in many papers. The present effort, therefore, is limited to a summary of existing information combined with an emphasis of the probability that the relative importance of controlling factors will change with advancing knowledge. Consequently the necessity for flexibility in laws and regulations, inherent in the problem, is emphasized. Definitions Many terms have been widely used in the literature without having been specifically defined. For example, confusion exists in the use of ((reservoir energy" and "gas energy." The latter is much more limited in meaning than the former. Other terms have been variously used. Consequently, I shall preface my remarks with definitions of a few of the more pertinent terms. Reservoir energy is that force or forces, active or potential, that is native to the reservoir and has the power to move oil through the reservoir rock. The energy may result from expanding gas, from hydrostatic head, from the weight of overburden, or from any other source. Gas energy is the expansive power of gas when pressure is reduced. It is one type of reservoir energy. An oil reservoir is that part of a geologic formation or formations in which oil occurs in commercial quantities wholly surrounded by nonproductive rock. The essence of this definition is effective separation rather than remoteness and under it oil reservoirs may be superimposed in the same oil pool. Conservation of reservoir energy means primarily its maximum use in the production of oil. Unit operation is a plan of development and production, which embraces an entire oil reservoir under a unity of engineering control. It is distinct from unitization, which has to do with arrangements of organization and equities to make unit operation possible in areas of divided ownership.

Jan 1, 1934

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 Reino Kurppa

The Pyhäsalmi mine of the Outokumpu Co. is located in central Finland (Fig. 1). The deposit was discovered in the autumn of 1958. Construction of the mine was started a year later, and production began on Mar. 1, 1962 (Fig. 2). At present, 750,000 metric tons (mt) of ore and a nearly equal amount of country rock are mined annually. Slightly over one-half million tons of various concentrates are produced per year, of which 85% is pyrite concentrate, 10% zinc concentrate, and 5% copper concentrate. The pyrite concentrate is treated in the company's pyrite smelter,1 yielding elementary sulfur, sulfur dioxide, and iron-oxide cinders, as well as electric power. Thus all the sulfides, totaling 75% of the ore, are of economic value. This is a fact which had a bearing on the development of the stoping method. GEOLOGY The ore is of breccia type containing fragments of country rock of varying sizes. It is coarse-grained pyrite ore containing sphalerite and chalcopyrite as a matrix between the pyrite grains. Only small amounts of pyrrhotite have been observed in certain marginal parts of the orebody. The ore averages 0.85% Cu, 3.0% Zn, 38% S, and 33% Fe. The orebody extends from the surface down to at least 500 m, which is the lowest level from which present information has been obtained. Horizontally, the orebody is 650 m long. It is 75 m wide at its central part, narrowing towards the ends (Fig. 3). At a depth of 115 m, the orebody suddenly narrows down to a thickness of 25 to 30 m. In the northern part of the orebody, the dip is 50° to 70°, but elsewhere it is almost vertical (Fig. 3).

Jan 1, 1969

By S. Skowronski

The melting of cathode copper, ususally containing 95.98+ per cent. • Cu, would appear to be a simple matter. Owing to the well known affinity of copper for sulfur, however, so much sulfur is absorbed by the copper during the operation that a long and expensive refining process is required to remove it, and the final product is inferior in purity and lower in electrical conductivity than the original cathode copper. The furnace operation, as now conducted, includes the following stages: 1. Charging the cathodes into the furnace. 2. Melting the cathodes. 3. Oxidizing period—saturating the copper with cuprous sub-oxide and bringing the metal to the condition known as "set copper;'' this is now done by blowing air into the molten bath of metal. 4. Reduction period, otherwise known as "poling," whereby the oxygen previously added is removed by covering the molten bath completely with coke or charcoal and introducing large poles of green wood; this reduces the cuprous sub-oxide, bringing the copper to the "tough pitch" stage ready for casting. 5. Casting Period. Many experiments have been made to obviate the long periods of oxidation and subsequent reduction, with no success. While the copper first cast will be good, as indicated by the set surface of the bars, it is impossible to hold it to the "tough pitch" condition, and long before the whole charge has been poured the copper will become "overpoled," entailing numerous difficulties. Sulfur has always been blamed by the furnace men as the reason why this refining process is necessary, yet the literature on the subject does not sufficiently emphasize how small a proportion of sulfur will ruin copper for practical purposes. The sulfur absorbed by copper during the melting period comes from two sources: (1) the sulfate left on the cathode sheets in the tank houses; (2) the fuel. The percentage of sulfates on the cathodes is variable, and depends on the care taken in washing the cathodes after removing

Jan 1, 1919

By H. W. Immolz

The Palo Pinto limestone pools of Jones and Shackelford Counties were defined and almost fully developed during the year. A new Palo Pinto limestone pool was apparently discovered when the K. B. Nowels NO. 1 Pardue, S.F.I. and W. survey, south central Haskell County, was completed for a small well in Palo Pinto limestonc at 3395 to 3421 feet. In Haskell County, Amerada Petroleum Corporation's C. J. Kleiner, J. M. Cass survey, drilled to the Ellenburger with a total depth of 5607 ft., where it was abandoned. A Bluff Creek sand field of undetermined size was discovered by the Fain-McGaha No. 1 Dawson-Conway, P. G. Holcomb survey, which was chompleted for 37 bbl. at 1496 feet. The Cook field was extended by the Roeser-Pendleton B-113 Cook in sec. 113, E.T.R.R. Co. survey, the well being completed for 510 bbl. from Cook sand encountered at 1545 to 1568 feet. Several shallow pools of minor importancc mere also discovered in Shackelford County during the year. In Jones County the Lewis and the Steffens fields, in block 15, T. and P.R.R. Co. survey, were further developed during the year but the limits of the Steffens field were not definitely defined. The most, important discovery in Jones County was the Guitar field, where most of the wells that had been producing from the Cook sand were deepened to the Hope limestone, a new producing horizon. In Taylor County, the Bowles field, see. 28, B.A.L. survey, was defined arid proved to he of minor importance. The Goldsboro and Novice area, ill northwest Coleman County, continued to hold considerable interest because of the developments near the town of Novice, where new Ieases continued to be opened for production. Nolan County was placed in the ranks of the producing counties when the S. B. Owens No. 1 Tipton, sec. 43, block 19, T. and P.R.R. Co. survey,

Jan 1, 1940

By Carl Scholz

During November and December, 1907, four serious mine-explosions occurred in the Appalachian coal-field, which resulted in the loss of nearly a thousand lives and caused an eliormous damage to propcrty. These accidents attracted more than the usual attention; coal-trade and engineering papers contained many comments and suggestions on the cause and prevention of accidents; the daily press in many instances condemned the coal-operators and charged these accidents to their negligence, or their anxiety to make money without adopting precautionary measures. Immediately after cach accident the respective State authorities ordered close investigations to be made, with the view of establishing the cause and suggesting remedies to prevent recurrence. Representatives of the Technologic Branch of the IT. S. Geological Survey, to whom the investigation of mine-accidents had recently been delegated by the Secretary of the Interior, visited the mines and co-operated with the local authorities in their determinations. It may be safe to say here that an investigation of a mine after an explosion has occurred discloses but little, because the causes hare been removed and conditions have been entirely changed. On Jan. 8, 1908, the coal-operators of West Virginia organized an association at qTashington for the purpose of making extensive investigations, and sufficient funds were pledged to carry out this work. At this organization meeting, the representatives of the Geological Survey present had no suggestions to offer as to the cause of these accidents. An examinatiou of the various reports concerning these accidents indicates that the explosions were caused by the ignition of gas or dust; they show the point of origin and the direction in which the force was expended, and give a detailed description of the damage done. Very little has bee11 said as to what

Jan 1, 1909

By Thomas V. Falkie, Robert Stefanko

Much has been said and written recently about the manpower problem in the mining industry. The coal segment of the industry has been scrambling to staff and man its companies and operations in order to accommodate the current boom, and there are some interesting side- lights and developments which deserve further attention from coal mining people. This column will deal with the manpower problem in general and the plight of the professional-the mining engineer-in particular. At this point in the game, it is desirable and perhaps necessary to ask ourselves if there really is a manpower problem and, if so, how serious it is. Suprisingly, there are varying and conflicting answers to this question. If we are talking about warm bodies, then in most mining areas there is no problem. If, however, we are talking about skilled or trained people-at all levels-there are apparently serious shortages, especially in the coal industry and in the U. S. Bureau of Mines. To define quantitatively the present and future need for mining professionals is a formidable task, to say the least. Without pretending that these figures are anything but an educated guess, we feel there is an immediate need for about 1000 mining engineers right now and a continuing need for about 300 mining school graduates per year (double last year's number) for the next ten years in order to take up the slack, provide for attrition and maintain a normal growth rate. Mining companies, large and small, are just now beginning to realize that the industry is undergoing a revolution, It is no longer possible to design, build and operate coal mines by the "seat of the pants." Production demands, the new health and safety law and the inevitable new legislation on surface mining will require more engineering, more planning and new technology. There are mine operators who need mining engineers and don't even know that they need them. This could mean rough going for the small operator. It surely means that there will be a trend toward increasing the ratio of technical to nontechnical employees and the ratio of technical employees to dollars of capital towards levels comparable with other highly mechanized industries.

Jan 1, 1971

AT THE beginning of November, Mussolini had firmly established himself at the head of the Italian Government. He himself referred to the ascendancy of the Fascisti as the result of a revo-lution and bluntly informed Parliament that it was to vote, as a matter of form, as he ordered, or else be dissolved. One of the great consequences of these events in Italy was the impetus that they gave to simi-lar movements in other countries of Continental Europe. Another great event of the month in world affairs was the repudiation by the Turks of the Mudania agreement and their notification to the Allies that the latter must evacuate Constantinople and allow the Dardanelles to be closed. This had the effect of once more consolidating Great Britain, France and Italy in so far as this question is concerned, and there was prompt refusal to accede to the demands of the Turks. With the advent of November, both the United States and Great Britain were in- the throes of political contests. The result of the American election was a landslide against the administration and especially was it an expression of agrarian discontent and a declara-tion in effect that our domestic affairs are not good in spite of political representations that they are. In Great Britain, the Conservatives were put in power by a substantial majority in Parliament, but the fact that the Labor party became numerically the second party instead of the Liberals and that it polled about 40 per cent. of the total popular vote affords ground for misgivings, especially when it be considered that the Labor party was standing on distinctly socialis-tic and communistic principles. In Russia, there was a sitting of the Third Interna-tionale, to which Lenin in a speech made a quasi-confession of the failure of the communistic experiment in Russia. He admitted, moreover, that Russia could not industrially reconstruct herself without capitalistic help. Nationally the country is making progress. During November, the Far Eastern Repub-lic surrendered to the Soviet, which thus carried Russia back to the shore of the Pacific.

Jan 12, 1922

By Gilbert P. Moore

Petroleum operations in Bolivia are still limited to those of the subsidiaries of the Standard Oil Co. of New Jersey. Development work is being carried on at Sanandita and at Bermejo and testing operations in the north. Five wells have been completed at Sanandita. Wells 1 and 2 are producers, 3 and 5, which are north of 1 and 2, are poor wells, and well 4, to the south, was dry. In the Bermejo field, well 5 has just been completed. No information as to the production is obtainable. In the north one string was operated at each of the following locations: Machareti, Camatindi and Camiri. The well completed at Machareti during the year was a failure. The result of the others is not known. It is reported on good authority that a pipe line will be completed in 1931 to connect the Sanandita field with the Lomitas field in the Argentine. This will place Bolivia among the ranks of the producing countries of South America for the first time. This development indicates that some arrangement has been arrived at with the Argentine Government for the importation of Bolivian oil. During 1930 the Bolivian Government declared in effect the new Petroleum Law which had been expected for such a long time. One of the first acts of the military junta, which rose to power through a coup d'état, was to cancel this law, so that Bolivian oil operations are still under the old law of 1921. One new local company was formed to exploit 1,500,000 hectares near the town of Cochabamba. The Bolivia Concessions, Ltd., which had a concession permitting the selection of 17,000,000 acres in eastern Bolivia, is reported to have failed in 1930 and is now being liquidated. Chile During 1930 the Chilean Government entered into a contract with an individual to explore in five distinct zones of the Republic. According to the contract, geologists must be at work there by May 1 of this year and a well must be started by the end of 1931. If the operations are

Jan 1, 1931

State of California, Division of Mines, Ferry bldg., San Francisco, Calif. Walter W. Bradley, State Mineralogist. A list of publications available will be sent upon request. Bulletin 77 is a list of publications complete from 1880 to 1917 and contains synopses It is sent free. Bulletin 105, California mineral production and directory of mineral producers for 1930, brings the complete list up to date, sent free on request The Division of Mines issues principally (1) A series of Reports, (2) Bulletins, (3) Preliminary Reports, and (4) maps. The Reports were first issued biennially, later annually, and for the past few years they have taken the form of quarterly reports. The yearly subscription price for the quarterly reports is $1, payable in advance Reports and separate chapters available are Report 2, First Biennial (1892), $1, 14 (1913-1914), Chapter on mines and mineral resources of Colusa, Glenn, Lake, Mann, Napa, Solano, Sonoma, and Yolo counties, 50 cents, 15 (1915?1916), Mines and mineral resources of Butte, Lassen, Modoc, Sutter and Tehama counties, 50 cents, and Mines and mineral resources of Monterey, San Benito, San Luis Obispo, Santa Barbara and Ventura counties, 65 cents, 16 (1917-1918), Nevada County, 75 cents, Plumas County, 50 cents, Sierra County, 50 cents; 17 (1920), Mining in California during 1920, $1 75, 18 (1922), Mining m California, chapters for Aug , Sept , Oct , Dec , free, 19 (1923), Mining in California, chapters for Jan , Feb , Mar, Sept , free, 20 (1924), Quarterly chapters on mining in California (except July, out of print), 25 cents, 21 (1925), Quarterly chapters containing county reports- Jan (Sarcramento, Monterey, Orange) 25 cents, April (Calaveras, Merced, San Joaquin, Stanislaus, Ventura), 25 cents, July (Del Norte, Humboldt, San Diego) 25 cents, Oct (Siskiyou, San Luis Obispo, Santa Barbara), 25 cents; 22 (1926), Quarterly county reports: Jan. (Santa Cruz, Trinity), 25 cents, April (Shasta, San Benito, Imperial), 25 cents, July (Mann, Sonoma) and Copper in California, 25 cents, Oct (El Dorado, Inyo) Minarets District, 25 cents, 23 (1927), Quarterly county reports- Jan (Contra Costa), 25 cents, April (Aniador, Solano) Bibliography of clay

Jan 1, 1933

By G. B. Pryde

IN laying out a new mine, provision should be made for the ultimate recovery of as much coal in any given bed as is consistent with safety and economic mining. Though each mining district, if not each individual mine, has problems that make the adoption of any hard and fast rule impossible, certain basic principles are adapted to practically all conditions. One of the most vital is the provision for barrier pillars of ample dimensions to protect all haulage and permanent airways during the life of the property. Where conditions permit, room or butt entries should be driven on the strike or slightly to the raise and rooms turned at right angles to said entries. The width of rooms and room pillars is governed by conditions prevailing in the mines under consideration. A safe rule is: In advancing, extract not more than 25 to 35 per cent. of the entire seam; in exceptionally thick seams, considerably less than 25 per cent. should be taken. Rooms usually vary in length from 250 to 350 ft. (76 to 106 m.) with a barrier pillar of not less than 80 ft. between the last crosscut in rooms, and entry and room crosscuts should be driven on sights; room crosscuts should be driven at right angles to the direction of the rooms. In mines under excessively heavy cover or where roof conditions are bad, rooms should be driven narrow and a barrier pillar left at every fifth to tenth room. This barrier should be of such dimensions that one or more rooms, with pillars of usual dimensions, may be turned through it when the barrier is no longer required. Two of the advantages of such a barrier are the protection of the panel against peaking of roof load during pillar extraction and the easy closing of the entry in case of fire.

Jan 2, 1921

By B. M. Loring, I. R. Krame, F. M. Walters

NO observations on the mechanical properties of man-manganese alloys have been published since pure manganese became readily available, either distilled manganese or electrolytic manganese. The purpose of this investigation was to determine whether iron-manganese alloys are essentially brittle, as reported by Hadfield,' or whether the lack of ductility observed was due to impurities in the alloys that he studied. Experimental Methods The alloys were melted in a roo-lb. high-frequency induction furnace with a magnesia crucible, using ingot iron and electrolytic manganese. The heats were split, the first giving six 18-lb, ingots and the second three. Each successive heat was higher in manganese and about 0.3 per cent silicon was added as ferrosilicon. The alloys forged without difficulty and were given a 9' per Published by permission of the Navy Department. Manuscript received at the office of the Institute June 28. 1941. Issued as T.P. 1369 in Metals Technology. September 1941. * Division of Physical Metallfirgy Naval Roscarch Laboratory. Anacostia Station Washington. D. C. 1 References are at the end of the paper. 4 cent reduction to ¾-in. rounds. The chemical analysis of the alloys is given in Table I. The forged rods were homogenized for 224 hr. at r150°C. (2100°F.) and air-cooled. The alloys were tested in two conditions of heat-treatment: (I) as normalized from 870°C. (1600°F.) and (2) normalized from 870°C. and tempered for I hr. at 540°C. (Iooo°F.) and air-cooled. The tensils specimens were 0.505 in. in diameter with a 2-in. gauge length, and the impact specimens were v-notch Charpy. The proportional limit and yield strength were taken from the stress-strain diagrams drawn by a Peters recorder. The data obtained from the tensile test and the hardness measurements are given in Table 2. Specimens that were normalized are designated by N; those that were normalized and tempered by T. Alloy G was tempered after forging (D).

Jan 1, 1942

By Leonard P. Skolnick

PROPERTIES of materials containing a hard con-stituent dispersed in a metallic matrix are dependent on the distribution of the hard phase.'-' The grain growth of titanium carbide in liquid nickel was studied in order to understand microstructural development in this and similar systems. Smith" has examined the influence of surface energy on the distribution of phases in alloys. The grain growth of tungsten carbide in cobalt has been the subject of many conflicting theories. Those prior to 1950 have been summarized by Goetzel.' Recently, Gurland and Norton3 and Gurland8 have indicated that growth occurs primarily by diffusion through the liquid phase in order to lower the inter-facial energy between the carbide and the liquid metal. In the development of the Ti-C-Ni ternary phase diagram, Stover and Wulff9 have shown that both eutectiferous dendritic titanium carbide, and primary titanium carbide which had developed crystals of cubic symmetry, were rounded by heating below the solidus, and that if primary carbide was already present the typical eutectic decomposition products were not formed. Experimental Procedure The infiltration technique was used to study the grain growth of titanium carbide in nickel. In contrast to sintering, infiltration more readily assures uniform dispersion of the two phases, and the problems associated with mixing by milling; i.e., mill contamination, breakdown of original carbide size in the operation, development of interfering surface films, etc., are avoided. In addition, the complicating effect of densification by shrinkage is eliminated. The titanium carbides used were commercial grades. Their chemical analyses, size distributions and shapes are summarized in Table I. Size analysis was conducted by microscopic count on a minimum

Jan 1, 1958