Search Documents

By H. W. Camp

ALTHOUGH the situation in the oil industry during the past year has. not been conducive to large expenditures for development and research, there is little indication that such expenditures have been curtailed. While few outstanding achievements have been reported, considerable progress has been made in the development of new products and the adaptation of petroleum derivatives to new uses. The most important question facing the refiner today is the anti-knock quality of his gasoline. This year has seen the widespread adoption of the term "octane number" as a measure for anti-knock values, and in the latter months of the year the public has been made acutely aware of this condition through competitive advertising. Gaso-line is no longer priced on volatility and gravity alone, but on octane number as well; and premiums are being paid for material of relatively high octane rating. The situation has grown more and more competitive and has forced refiners continually to raise the octane rating of their regular and com-petitive grades, and at this writing the same situation exists for premium grades which have possessed relatively high anti-knock properties for some time. Straight-run gasoline produced from paraffin-base or semiparaffin-base crudes has an inherently low anti-knock value, and in order to convert this material to a higher quality it has been found necessary to crack an increasing percentage of the crude oil charge. By completely cracking the heavier portions of the crude, and blending back with the straight-run gasoline, it has been possible to produce an average of 63 to 65 octane number gasoline' on average Mid-Continent crude. This operation carried to the fullest extent does not suffice, however, and the recent and rapid development of the so-called "re-forming unit," has resulted. The straight-run gasoline fraction is cut into two parts: a light, low boiling point gasoline; and a heavy gasoline or naphtha. The latter containing the low anti-knock portions of the gasoline, is sent through a re-forming unit and subjected either to high temperature ,or pressure, or both, which materially increases its octane number. On average Mid-Continent the blend of low boiling point straight-run,

Jan 1, 1932

By William P. Blake

This camp is just now startled by the alarming suggestion that unless there shall speedily be an appreciation in the value of silver, and a decrease in the cost of salt, it will be prudent business policy to close the Alice mines and mills until the conditions of production are more favorable. Such an event would be a great blow to the prosperity of Butte. It would throw some hundreds of men out of employment, and it might lead to the adoption of the same policy by other companies, which, like the Alice, have not been able to pay dividends to their shareholders for a long time. The question arises, and becomes emphatic: If, under the present adverse conditions, the mines and mills cannot be made to pay a proper profit, why should they continue to be worked ? The owners mentally ask: Shall we go on exhausting our mines, pouring out a stream of silver for the maintenance of the community, and the support of the rail ways, or shall we husband our reserves, withdraw the miners from our slopes, and wait for more favorable conditions ? This is the impending question, and all concerned dread to meet and answer it. Let us briefly review the situation and forecast, if possible, what the solution of' the problem will be. It must be understood that the discussion does not include, or refer to, the immense copper-producing interests of the camp, which may or may not be upon a very much more satisfactory basis. It will be confined chiefly to the operations of the Alice company, sta tistics of which are at hand, without involving the other silver com panies in the conclusions beyond those inevitable from well-known facts, patent to all. There are at present in Butte and in its vicinity in the principal mills an aggregate of 290 stamps dropping upon silver-ores: Alice,...........80 stamps. Moulton,. .........40 " Lexington,...50 " Silver Bow,.........30 " Blue Bird,..........90 " The Alice mills at present, with their 80 stamps, devour, in round numbers, from 100 to 120 tons a day. The actual amount

Jan 1, 1888

By John B. Myers

VERMICULITE is a name used to describe micaceous material that exfoliates when heated. It is hydrated magnesium-aluminum-iron silicate. The chemical composition, color, physical appearance, and degree of exfoliation vary. COMPOSITION, PROPERTIES, AND ORIGIN Vermiculite has the characteristic micaceous structure of basal cleavage and readily splits into thin laminae, which are soft, pliable, and inelastic. The monoclinic crystal faces are often marked by triangular lines at 60° and 120°. Hardness is 1.5; specific gravity, 2.2-2.7; luster pearly to greasy; colors, amber, bronze, reddish brown, dark green, and black. Feel is soapy, particularly when wet. When heated it exfoliates by expanding at right angles to the cleavage into long wormlike pieces (the name vermiculite is from the Latin veamiculari, to breed worms). This important characteristic of expansion is believed to be a mechanical separation of the layers when the contained water is converted into steam. Warping of the unit layers may also contribute to the expansion. The increase in bulk volume of commercially prepared material is 8 to 12 times but individual flakes may increase in size more than this. Pure vermiculite is a distinct mineral and has the structural formula (OH), (Mg,Fe)3 (Si,Al,Fe)4 010.4H20. It rarely occurs in this pure form, but generally as a mixed mineral of varying structure. One explanation is that the mixed material is composed of unit layers of inter-stratified pure vermiculite and biotite. The essential difference between the two is that unit cell structure of vermiculite contains a layer of water molecules whereas the biotite cell contains potassium instead of the water. The water content of the mixed vermiculite is less than that of pure vermiculite but more than that of biotite. Pure biotite does not expand when heated. If the proportion of biotite layers in a vermiculite is too high it will adversely affect the degree of exfoliation. Within a given deposit, the great mass of material may approach a definite com-position with local areas of greater biotite content. It is not uncommon to find also small pockets of pure biotite but these are generally segre-

Jan 1, 1949

By H. T. Morris

ONE of the chief concerns of the Bethlehem Steel Co. naturally is the proper functioning of its organization. This involves the training of a continuous supply of younger men to fill the vacancies caused not only by the inevitable departure of older men, but also by the growth of existing establishment, and by expansion in new directions. It does not oper-ate a student training course with a fixed time schedule or with definite periods of rotation through the differ-ent divisions. To state the case positively, the gradu-ate's training course must operate continuously from the beginning of his employment through a long term of years. No period of weeks or months nor pair of years suffice to bring him into contact with all the com-binations needed to qualify him for the larger destiny toward which we hope he is headed. Our first step in selecting a college man is to require that he have a degree. We thus approximate the assur-ance that at least four annual siftings have reduced the chance that a non-worker may find himself in a job where work is necessary. The next step is to try to ascertain facts, from the graduate and from others who have known him at his home and in 'his college, to indi-cate whether our opportunities offer him a career that will challenge his continuing interest, and hold him to tenacious effort against all happenings. We aim to avoid knowingly bringing into our organization a man who will not develop in it enough enthusiasm to keep him happily striving. Having made our selections, we assemble the gradu-ates into a probationary observation circuit. We-put ourselves under their observation by taking them in small groups, usually of two to four men, on a circuit of every part of the Bethlehem plant, in which every manufacturing principle of our steel business is ex-emplified. The probationers work at something from day to day, with their hands if it can be arranged; otherwise in questioning, examining, and note-taking. Their observations include talks with superintendents, foremen, and workmen, the conditions under which workmen labor, apparatus, machinery, methods, design and operation of plant.

Jan 7, 1928

By Harry Klemic

Zirconium and hafnium minerals are used industrially both as minerals valuable for their chemical and physical characteristics and as ores of zirconium and hafnium. The principal zirconium-hafnium-bearing minerals, their composition, and their ranges in content of zirconium and hafnium dioxides are listed in Table 1. The supply of zirconium and hafnium is based almost entirely upon the supply of the minerals zircon and baddeleyite. Eudialyte may eventually also be of importance as a source of these elements. Zircon, which generally contains nearly 49% zirconium and between 0.4 and 1.5% hafnium, is the principal industrial mineral of this group. Baddeleyite, a commercially important but less abundant mineral, contains as much as 73% zirconium and 0.4 to 1.7% hafnium. Eudialyte has a wide range in content of these elements, but analyses of material from several localities indicate values of 6 to 11 % zirconium and 0.07 to 0.4% hafnium. Zircon is a mineral consisting principally of zirconium, silicon, and oxygen that crystallizes from magmas during the formation of igneous rocks. Zircon also occurs in veins and in metamorphic rocks. It is in the tetragonal crystal system. It commonly forms as small well-developed prisms having pyramidal terminations but also occurs as irregular-shaped grains. Zircon has a hardness of 7.5 on the Mohs' scale. Its specific gravity is commonly between 4.68 and 4.70 (Dana, 1932), but the specific gravity varies somewhat depending upon com- position and state of alteration. Zircon has no good cleavage directions and is brittle, breaking with a conchoidal fracture. Zircon of the composition ZrSiO, would contain 67.2% Zr02 and 32.8% SiO2. However, in addition to about 1 % of hafnium, minor amounts of thorium, uranium, rare earth elements, yttrium, calcium, magnesium, iron, aluminum, phosphorus, and hydrogen, and trace amounts of other elements are commonly present in the mineral (Frondel, 1957). Radiogenic lead and other daughter products from the radioactive decay of uranium and thorium also accrue in the mineral. Radiation damage to the structure of zircons that contain appreciable amounts of uranium and thorium may alter the internal structure of the crystals to

Jan 1, 1975

By H. E. Ellis, O. L. Patterson, Granville Dutton

A large-scale water-injection program for the Holt Bryant reservoir of the Delhi field has been established by means of the new automatic multi-pool analyzer. The objectives of this program were to increase reservoir pressure and eliminate a cross-dip gradient of 200 psi. Pressure increases during the first 15 months of operation have allowed for increased oil production rates of 2,600 BID or 25 per cent. To determine the required water injection it was necessary to predict natural water influx ram. Elimination of the pressure gradients required the water-injection program to account for the fluid migration and pressure interaction between segments of the reservoir. An integral part of the ana1ysis included the determination of in-place volumes of oil and gas. The operation of the automatic multi-pool analyzer in determining the water-injection program is described. New features of the analyzer inc1ude an automatic maferial balance analog and a leart-squares computer for determination of unknown reservoir properties. Operational procedures are sufficiently simple to allow direct use by reservoir engineers on a routine basis. The rapidity and accuracy with which problems may be solved permit repeated ana1yses as a check upon reservoir performance. INTRODUCTION This paper describes the use of a new analog com- puter in determining the optimum injection program for a complex reservoir. The Holt-Bryant (Fig. 1) is the major reservoir in the Delhi field of Louisiana. Production is from the Tuscaloosa at subsea depths of 2,970 to 3,286 ft. The sand dips to the south and southwest from three to five degrees. The reservoir is approximately 12 miles long and varies in width from 1/2 to 2 miles. Various calculations have placed the initial volume of oil in-place in the wide range of 275 to 355 million STB. Two small gas caps were initially present in the reservoir. The Holt-Bryant reservoir was discovered in Dec.. 1944, and was fully developed with 188 producing wells by 1948. After development was completed, an east-west pressure gradient began to establish itself. This

Jan 1, 1957

By Benjamin C. Craft

Oil and gas development in Louisiana during 1935 brought this state at the close of the year up to fourth place in the nation as a producing area. A review of development in North Louisiana centers around Rodessa, the most important reserve discovered in this area in many years. While the producing limits have not been defined, this discovery is one of the major developments of the year. New gas fields were discovered in Lincoln, De Soto and Bossier parishes. The Lincoln Parish discovery, completed flowing a highly saturated gas from the Glen Rose, further indicates the importance of deep-seated prospects in the interior salt-dome area. Minor extensions were made at Sligo and Pine Island. During the year, 126 oil wells and 103 gas wells were completed in North Louisiana as compared with 144 oil wells and 68 gas wells during 1934. The North Louisiana oil production was 9,617,405 bbl. as com-pared with 9,274,050 bbl. during 1934, an increase of 343,355 bbl., while the gas production increased 18 billion cu. ft. in 1935 over its 1934 figure. The Louisiana Department of Conservation gage of Nov. 1, 1935, shows an open-flow capacity of 4,563,725,000 cu. ft. per day from 941 wells in the Monroe field and 682,770,000 cu. ft. from 159 wells in the Rich-land field. A great deal of leasing continues in North Louisiana as a result of the Lincoln Parish discovery and development in the Rodessa field, especially in Bossier, De Soto, Winn, Lincoln, Bienville, Webster, Ouachita and Richland parishes. South Louisiana's position as an area of important reserves was further proved during the past year. Increased drilling resulted in the discovery of seven new fields: Lafitte, Garden Island Bay, Tepetate, Bunkie, St. Martinsville, Jeanerette and Big Lake. New sands or producing horizons proved productive in 15 of the proven fields. The total oil production for South Louisiana during 1935 was 40,731,-056 bbl. as compared with 23,255,437 bbl. during 1934. There were 222 oil and gas wells completed in South Louisiana during 1935 as compared with 214 oil wells during the previous period. Drilling during

Jan 1, 1936

By Benjamin C. Craft

Oil and gas development in Louisiana during 1935 brought this state at the close of the year up to fourth place in the nation as a producing area. A review of development in North Louisiana centers around Rodessa, the most important reserve discovered in this area in many years. While the producing limits have not been defined, this discovery is one of the major developments of the year. New gas fields were discovered in Lincoln, De Soto and Bossier parishes. The Lincoln Parish discovery, completed flowing a highly saturated gas from the Glen Rose, further indicates the importance of deep-seated prospects in the interior salt-dome area. Minor extensions were made at Sligo and Pine Island. During the year, 126 oil wells and 103 gas wells were completed in North Louisiana as compared with 144 oil wells and 68 gas wells during 1934. The North Louisiana oil production was 9,617,405 bbl. as com-pared with 9,274,050 bbl. during 1934, an increase of 343,355 bbl., while the gas production increased 18 billion cu. ft. in 1935 over its 1934 figure. The Louisiana Department of Conservation gage of Nov. 1, 1935, shows an open-flow capacity of 4,563,725,000 cu. ft. per day from 941 wells in the Monroe field and 682,770,000 cu. ft. from 159 wells in the Rich-land field. A great deal of leasing continues in North Louisiana as a result of the Lincoln Parish discovery and development in the Rodessa field, especially in Bossier, De Soto, Winn, Lincoln, Bienville, Webster, Ouachita and Richland parishes. South Louisiana's position as an area of important reserves was further proved during the past year. Increased drilling resulted in the discovery of seven new fields: Lafitte, Garden Island Bay, Tepetate, Bunkie, St. Martinsville, Jeanerette and Big Lake. New sands or producing horizons proved productive in 15 of the proven fields. The total oil production for South Louisiana during 1935 was 40,731,-056 bbl. as compared with 23,255,437 bbl. during 1934. There were 222 oil and gas wells completed in South Louisiana during 1935 as compared with 214 oil wells during the previous period. Drilling during

Jan 1, 1936

By Benjamin C. Craft

As predicted, during 1937 South Louisiana witnessed one of the most active drilling campaigns in the history of the area, resulting in the discovery .of 14 new fields. The economic importance of 10,000-ft. production was far-reaching and the objective depths placed on some wildcats was 12,000 feet. Most of the important discoveries and deep tests were in the delta area between the Atchafalaya and Mississippi Rivers, where the upper Miocene sands were found productive between 10,000 and 11,000 ft. The casing program on these wells usually called for a protection string of 95/8-in. casing at approximately 9500 ft. Drilling barges with the heaviest equipment were used where water transportation was available. The oil production for South Louisiana during 1937 was 62,147,690 bbl., as compared with 51,968,727 bbl. during 1936, an increase of 19.5 per cent. There were 281 oil and gas wells and 172 dry holes completed during 1937 as compared with 262 oil and gas wells and 135 dry holes during the previous period. New Fields Gibson.—The first discovery for the year was in the Gibson area, where Shell Petroleum Corporation's Realty Operators No. 1, sec. 18, 17 S., 15 E., Terrebonne Parish, was completed flowing 780 bbl. of 38° A.P.I. oil daily through a 14/64-in. choke with a tubing pressure of 1700 lb. Production is from upper Miocene sand found from 9461 to 9483 feet. Abbevil1e.—The discovery well for the Abbeville field was Continental Oil Company's Hebert No. 1, sec. 20, 12 S., 3 E., Vermilion Parish, completed flowing 50 bbl. of distillate and 2 million cubic feet of gas through a 3/16-in. choke with a tubing pressure of 2550 lb. The well was plugged back from 12,216 ft. in the Chickisawhay, and is producing through perforations from upper Miocene sand found from 7668 to 7682 ft. Later in the year, the same operators completed Brookshire No. 1, sec. 66, 12 S., 3 E., flowing 366 bbl. of 42° A.P.I. oil per day through a 3/16-in. choke with a tubing pressure of 1800 lb. This well was com-

Jan 1, 1938

By Leroy U. Gardner

EVERY reader of this paper is well aware of the fact that the prolonged inhalation of large amounts of free silica dust results in fibrosis of the lungs, and that other inorganic dusts, except those of asbestos and the mineral poisons, are thought to be relatively harmless. But probably few have had opportunity to visualize the effects of silica, asbestos and other minerals upon living tissues. The ideal demonstration would be based upon sections of lungs from human beings that had inhaled com- parable concentrations of different dusts for a unit period of time. Such material is generally difficult to obtain and in some instances is of questionable value because the subject has been exposed to more than one kind of dust. A demonstration could be prepared from the lungs of animals. However, so many months or even years are required to complete the exposure to each kind of dust that enough material has not been accumulated. For a general survey of the action of different types of dust, I am therefore compelled to use the tissues of animals that have been injected with suspensions of dust particles. The injection method offers certain advantages. The quantity, the particle size and the state of dispersion can be controlled with sufficient accuracy so that the tissue responses to different minerals can be accurately compared. The method insures contact between the tissues and the mineral particles; protective mechanisms, which may prevent the inhalation of certain types of foreign body, never come into play. If the pathway of injection be one that minimizes nonspecific injury, the tissue responses may simulate those produced by inhalation but they develop somewhat more rapidly. It should always be remembered that injection methods merely demonstrate the capacity of various kinds of minerals to provoke reaction in the tissues; whether the same substances are inhaled from atmospheric suspension and accumulate in the lungs in dangerous quantities can be demonstrated only by inhalation. The reactions that I shall discuss first took place not in the lungs but in the liver. For the purpose in hand this is quite immaterial for we are merely seeking to discover whether these minerals are capable of produc-

Jan 1, 1938

By L. C. Uren

Field studies and laboratory research have established the fact that the expulsive force which drives petroleum into wells, from the reservoir sands in which it is stored by nature, is primarly an expression of the energy latent within compressed natural gas dissolved or occluded in, or otherwise associated with the oil. Each barrel of oil produced is forced into the recovery well by the expansive energy of a certain volume of compressed gas, originally stored with the oil in the pores of the reservoir rock; and each cubic foot of gas so produced with the oil and expanded to atmospheric pressure reduces by so much the total natural energy available for oil expulsion. This relationship between the volumes of gas and oil produced has seemed so important that petroleum production technolo-gists have come to regard the "gas-oil ratio," or the "gas factor" as it has been more conveniently termed, as a measure of oil-production efficiency. Different methods of oil recovery and production devices are now Com pared on this basis and estimates of ultimate recovery obtainable through their use are considered by many to be inversely proportional to the values of their respective gas factors. The writer has been among those who have given support to a widcspread movement toward a proper recognition of the significance of the gas factor as a guide in the control of producing oil wells, and does not wish to oppose its more extended application. It seems necessary, how-cvcr, in view of the almost elemental faith with which the principle of the gas factor has been received in many quarters, to point out that it is a most complex factor, and one which cannot be regarded as an absolute index of production efficiency without due regard to other contributing factors by which it is influenced to an important degree. Variables Influencing Gas Factor The mere recording of a low gas factor, obtained through the use of some method or device, does not necessarily imply efficient oil production; and conversely, a high gas factor does not always signify inefficient recov-

Jan 1, 1928

By R. H. Card

THE geophysicist is interested greatly in the resistivities of different formations or parts of the earth's crust; sometimes he is interested in a single figure in the nature of an average, or what may be called the effec-tive resistivity, of all the formations or parts of the crust at a given location to a certain depth. Conversely, the engineer whose work is concerned with the coordination of power and communication lines in such a manner as to avoid electrical interference between these two types of facilities is concerned very much with this effective resistivity; to a lesser extent he is interested in the resistivities of individual forma-tions. In connection with his work the coordination engineer often estimates the effective resistivity; of the earth from measurements of the mutual impedances of lines; in other instances he derives front measure-ments of a different type the resistivities of different layers of the crust and synthesizes these to obtain an estimate of the effective resistivity. In connection with problems concerning the coordination of power and telephone lines, measurements from which earth resistivities can be estimated have been made at many points in the United States by the American Telephone and Telegraph Co. and its associated companies, in cooperation with various power companies and with railroad companies having electrified sections of line. Other such measurements have been made by the Joint Subcommittee on Development and Research of the Edison Electric Institute and the Bell Telephone System. A study has been made of the correlation of these data with the ages and types of materials of the strata of the earth's crust at each of the test locations. The purpose of this study has been primarily to provide information to assist in predicting the order of magnitude of effective resistivities to be used in the preliminary consideration of problems con-cerned with the coordination of power and communication lines. To make the results of such a study, most useful, it is essential that the geo-logical data to be secured when such a prediction is wanted be readily obtainable. Data on the ages of strata and the types of materials com-posing geological structures can usually be obtained, therefore particu-

Jan 1, 1937

By C. A. Stetefeldt

Metallurgical processes cannot be conducted successfully With out the aid of analytical chemistry. The great perfection of Iead smelting in the West, for instance, has only been accomplished by the analysis of ores, fluxes, slags and all products of the furnace. Ores are mixed and fluxed to obtain a slag of desired composition. Account is even taken of the composition of the ashes obtained from the coke. The " muscular " smelter has left the field forever! This state of affairs has been induced by sharp competition, i.e., by a com plete separation of the industries of mining and reducing ores, not by the liberality and wisdom of directors and stockholders to pro vide laboratories and engage chemists, or by their love for scientific investigation. It would be considered absurd, at present, to run a lead-smelter, a blast-furnace for pig-iron, or a Bessemer plant without the assist ance of a well-equipped laboratory and a chemist; but it is con sidered quite sufficient to provide amalgamation- or lixiviation works merely with a crude assay-office, and an assayer who is paid less than a laborer in the mill. In my opinion, this will change in the near future. By the ex clusion of Mexican lead-ores, and their growiring scarcity in the West, smelters have been forced to raise their charges on so-called dry silver-ores, and cannot handle the latter now in such unlimited quantities as formerly. The inevitable result must be that the sur plus of these dry silver-ores, especially those of low grade, will be reduced by processes cheaper than smelbing; and here the introduc tion of lixiviation has an excellent field, provided the muscular lixiviator has an able chemist for an assistant. It is to be regretted that so little analytical work has been done in lixiviation. We know almost nothing of the composition of roasted ores before and after lixiviation; of the constitution of the first wash water and of lixiviation-solutions after prolonged use; of the chemistry of sodium and calcium sulphides; of the col-hposition

Jan 1, 1892

By M. C. Udy, P. C. Rosenthal

THE use of minute boron additions to steel has been given considerable attention in recent years. Comparisons made between boron-free and boron-containing heats of otherwise identical analysis have indicated, beyond a doubt, the potent effect of boron for increasing hardenability. The actual hardenability increase has been expressed as a multiplying factor, or in terms of the percentage of other alloying elements boron might replace, The present study presents the results of a systematic survey of. the use of boron as an addition to two types of alloyed steels and as a replacement for various percentages of molybdenum in these steels, Both cast and wrought steels of the two basic compositions were prepared. Molybdenum, because of its scarcity at the time the investigation was started, was selected as the element to be replaced by boron. Attention was also given to the effects of boron on other properties of the steels, particularly their notched-bar toughness, to investigate other advantages or limitations of this element as an alloy addition. EXPERIMENTAL WORK Steels Investigated The two basic compositions used in this survey of boron as a replacement for molybdenum are given in Table I. The cast steels were higher than the wrought steels in silicon content to improve the casting quality. [ ] Each of these base steels, both cast and wrought, was made with molybdenum contents of o, 0.10, 0.20, 0.30, or 0.40 per cent, the total comprising 20 steels. In addition, each of these 20 compositions . was prepared with boron additions in amounts of 0.0015, 0.003, and o,006 per cent as ferroboron; and in amounts of 0.002 and 0.005 per cent as two com¬mercial intensifier alloys, designated alloys A and B. The boron-treated steels totaled 100, and the entire series 120, Test Procedure Each steel was melted as an individual heat in a 50-lb., magnesia-lined induction furnace. Ingot iron scrap or mixtures of ingot iron and steel scrap were used for melting stock. Deoxidation was carried out in the furnace with o.10 per cent aluminum. The aluminum addition was

Jan 1, 1946

Date of Congress: Sept. 20-25, 1915 The Committee on Local Affairs is fortunate in having secured for a period expiring on Oct. 17, an option. on 100 rooms at the Palace, St. Francis. and Fairmont hotels, the three leading hotels in San Francisco, with the distinct understanding that, on account of previous engagements whereby the hotels are reserved to their capacity, the rooms must be vacated on Sept. 25, 1915. The rates applying will be $7 per day for the court rooms occupied by two people, or $10 per clay for outside rooms occupied by two people. The outside rooms will face the main thoroughfares at the Palace and will face the city and bay at the Fairmont, which latter is situated oil a high hill. The St. Francis faces an open square and is flanked by main thoroughfares on two sides. If any members desire their reservation to extend either before the 20th or beyond the 25th, the Committee will use its best endeavors to secure such extension in individual cases, in accordance with the indicated wish. The Hotel Bureau in San Francisco is co-operating actively and closely with the. Committee on Local Affairs of the International Engineering Congress and offers the choicest rooms in any of 350 hotels other than the three mentioned above. This Hotel Bureau controls 50,000 rooms in San Francisco, which are all provided with hot and cold water, stationary basins, baths, house telephones, elevators, and bell boy service.

Jan 9, 1914

THE following employment items are made available to AIME members on a nonprofit basis by the Engineering Societies Personnel Service, Inc , operating in cooperation with the Four Founder Societies Local offices of the Personnel Service are at 8 W 40th St , New York 18, 100 Farnsworth Ave, Detroit, 57 Post St , San Francisco, 84 E Randolph St , Chicago 1 Applicants should address all mail to the proper key numbers in care of the New York office and include 6c in stomps for forwarding and returning application The applicant agrees, if placed in a position by means of the Service, to pay the placement fee listed by the Service AIME members may secure a weekly bulletin of positions available for $3 50 a quarter, $12 a year MEN AVAILABLE Executive Engineer, 37, married, 3 children Now Resident Manager nonmetallic underground mine and processing plant Management and operational experience in gold, copper, zinc, limestone and lime products manufacture Mine plant design and construction, underground mines and quarries Excellent references Currently employed but available reasonable notice Prefer U S M-687-426-E-5-San Francisco Metallurgical Engineer, 29, married, one child, B S Metallurgical Engineering Five years' practical experience in milling and laboratory research Available thirty days Prefer West or Southwest U S A M-689¬522-E-1-San Francisco Experienced Mining Engineer, university graduate, 40, married Twenty years' experience all phases metal mining, past 13 years as manager, excellent cost and safety record Available short notice Best references and complete professional record available upon request M-690

Jan 1, 1952

By P. Eadington

I feel sure that the apparent anomolies between his findings and ours arise as a result of the different experimental methods used. The modem oxygen electrode method he used is sensitive to nano moles of oxygen uptake whereas the method we used was only sensitive to micro moles at best. Furthermore, our experimental method did not permit measurements to be made in the first ten to fifteen minutes of reaction, the very time he is observing. Direct comparison of his data to ours is made difficult because of not knowing the specific area of the samples he used. However, we found that precipitation of PbS using sodium sulphide gave rise to samples of area approximately 30 m2 g - 1. Noticing the rapid decline in oxidation rate over ten minutes, as reported in Table 1, one can conclude that we could not measure the rate after ten minutes using our method. Taking the above area I estimate that at these rates only a small fraction of surface would be oxidised in a period of hours. I can only conclude that at some point a change in oxidation mechanisms occurs giving rise to a much faster rate such as we observed. Finally, I would like to comment on the apparent inertness of the homogeneously precipitated lead sulphide sample 11. This method of preparation we found to give specific areas of 20 to 30 times less than other methods and this would account for the very low oxidation rate.

Jan 1, 1982

By F. C. Blare

THE best method for the estimation of copper in ores and secondary products is that proposed by Dr. Steinbeck* for the award offered by the Mansfeld'schen Ober-Berg-und Hutten-Direction. It is based upon the decolorization of the blue ammonia solution of copper by potassic cyanide,† It is necessary for the accurate estimation of copper in arsenides that the arsenic be separated from the copper before the ammonia solution is made. The presence of a notable amount of arsenic renders the titration by potassic cyanide inaccurate, the end reaction being obscured by the appearance of a yellowish-green tint towards the end of the titration. The change of the color of the ammonia solution from blue to the tint caused by the presence of arsenic cannot be used for an end reaction, for the intensity and quick appearance of the latter-color depend upon the amount of arsenic present in the solution. In the analysis of speise, the method of separating the copper by an oxidizing and reducing treatment in the muffle, to volatilize the arsenic, gives poor results, and there may easily be some loss of the weighed sample. The separation of the precipitated sulphides of arsenic and copper by treating with sodic sulphide, gives good results, but the process is tedious. I have used the two following methods, which are simpler and more expeditious than those mentioned, with good results. * Fresenius, Zeitschrift Air Anal. Chemie., viii, 1. †First noted by Parkes in the Mining Journal for 1861.

Jan 1, 1881

By Roy P. Hudson

A micropyrometer known as the De Graaf apparatus has several advantages over the gas-furnace method for determining ash fusibility. When the De Graaf apparatus is operated by a modified method of procedure, the results closely check those of the gas-furnace method. This is indicated by tests on 27 samples of coal ash, with an extreme variation in fusibility values of 654" F. However, most of the ashes fused at temperatures between 2300º and 2500º. This, presumably, is the temperature interval within which the micropyrometer gives the best results. Additional comparisons are desirable. DISCUSSION (Thomas G. Fear presiding) A. C. FIELDNER,† Washington, D. C. (written discussion‡).-—The Pittsburgh Experiment Station of the Bureau of Mines has made two investigations1 of the micropyrometer for determining the fusibility of coal ash. These studies were undertaken with a view to adopting the micropyrometer method us a substitute or alternate to the present standard gas-furnace method, in view of the obvious advantages of greater speed, smaller ash sample, smaller laboratory space requirements, less equipment and greater comfort to the operator. However, the investigation showed that the micropyrometer type of furnace as then operated in five laboratories having this equipment could not be accepted as an alternate to the standard gas furnace, which is capable of close duplication in different laboratories, as shown in a recent colmparison between the Pittsburgh Experiment Station of the United States Bureau of Mines and the Fuel Research Station of Great Britain.2 The algebraic meau

Jan 1, 1934

By Edward A. Vitunac

The emerging importance of pneumatic conveying systems for bulk materials is largely due to the economic advantages such systems frequently exhibit when compared to alternate methods. Included in these advantages are relative simplicity, ease of installation, flexibility, ease of maintenance, cleanliness, safety and ease of automation to the degree desired. In general, installed costs favor a pneumatic system when compared to competing mechanical systems if the transporting distances are long or to and from many points. In addition, supplemental use such as cooling, heating, or drying may supply the incremental value required to justify its selection.1 The main disadvantages of a pneumatic system are the greater horsepower required per unit weight of material conveyed, material limits in abrasiveness, and density. In addition, material breakage tends to increase at changes of direction and at any obstruction such as that caused by the imperfect butting of two pipe sections in the conveying line. Classification of the material at the discharge may also cause problems in dusting and segregation. Materials weighing less than 4 lb per cu ft tend to cause feeding and collecting problems although they can be conveyed easily. Material between 4 lb and 20 lb per cu ft can be handled with fewer problems, but flow rate is hard to predict. The 20-60 lb per cu ft range offers best results, whereas materials of over 60 Ib per cu ft tend to drop out of the air stream and settle in the pipeline unless careful pro- visions are made to prevent this.2

Jan 5, 1968