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WHEN the new sulphide plant started to roll at Chuquicamata last July, we broached the matter of looking in on this historic event to Burr Wheeler, then executive vice president of Chile Exploration Co. (Chilex executive offices are housed with the parent company, Anaconda, at 25 Broadway which is 23 hours and 15 minutes closer to the AIME office than the mine, counting air and automobile travel). Mr. Wheeler was at Chuqui when they turned the first shovelful of earth, has an understandable pride and affection in the mine, and kindly offered to make all arrangements. As a guest of Chilex, physical exam, injections, police clearance, passport, and airline reservations on the crack Panagra airline are procured swiftly and almost painlessly. Winter clothes were advised by Mr. Wheeler and D. M. Dunbar, who is the former's assistant and a seasoned Chuqui-ite. Both of these gentlemen obviously prefer Chuqui climate, with 364 days of sunshine, 1 ½ -in. rainfall, rare atmosphere of 10,000 ft elevation, Christmas-time earthquakes, and howling winds through June and July to the vicissitudes of New York weather. Panagra's de luxe DC-6 noses in toward land at Antofagasta, Chile, the supply and embarkation port for Chuquicamata. The Coastal Range, completely barren of green, thrusts a spur far out into the Pacific creating a crescent-shaped and protected harbor at Antofagasta. Beach gives way to pampa, to hills, and the only variation in scenery is in topographic relief. Chilex's reception committee in the person of the alert and amiable Bob Condit, assistant port agent, takes care of everything: immigration, interviews by the local press, baggage, transportation, and introduction to Chilean cuisine. The drive up to Chuqui takes about three hours, on the only two lane highway in northern Chile; hard surfaced, with a few kilometers of repair work in progress. We were fortunate to make the trip with manager Charles Brinckerhoff, who arrived the same day at Antofagasta from the seat of government at Santiago where he goes frequently to keep in touch with the company's Santiago office.

Jan 1, 1952

THE increased demand for titanium alloys with improved high-temperature creep strengths has stimulated interest in silicon as an alloying addition to titanium. Silicon is a potent solid-solution strength-ener and, if added in sufficient concentration and properly heat-treated, can also dispersion-strengthen titanium by eutectoid decomposition.' However, better understanding of the nature and distribution of the resulting silicide dispersion in more highly alloyed titanium matrices is necessary for the development of useful titanium alloys which utilize the latter strengthening mechanism. This note describes the chemical and crystallographic characteristics of the silicide phase as it occurs in a typical high-temperature near-a titanium alloy matrix. Several Ti-6A1-3Sn-3Zr a11oys containing various amounts of silicon ranging from 0.1 to 1.0 pct were melted as 10- to 20-lb ingots and processed into 1/2-in.-diam bar stock. The microstructures of specimens annealed at various temperatures were conveniently summarized by the (Ti-6Al-3Sn-3Zr)-Si pseudobinary phase diagram illustrated in Fig. 1. Comparison with the Ti-Si equilibrium diagram indicates the substitutional solutes (Al-Sn-Zr) increase the eutectoid temperature and decrease the a terminal solubility. Annealing at temperatures sufficiently high to dissolve the silicon in a ß solid solution and cooling rapidly enough to preclude coarsening generally produced a uniform dispersion of fine silicide particles, whereas annealing at temperatures near but below the ß transus produced relatively coarse silicide particles. Annealing in the limited a, plus 3 region produced a duplex coarse and fine silicide array. Several a-annealed specimens were examined by X-ray diffraction to determine the crystallographic identity of the precipitate phase. Copper Ka X-ray diffraction patterns of bulk specimens which contained 0.5 and 0.8 pct Si were virtually identical to that of the silicon-free Ti-6Al-3Sn-3Zr base alloy except for a slight shift in some of the high-angle diffraction lines. Apparently the silicide volume fraction was too low to be detected in bulk specimens. X-

Jan 1, 1969

By Joseph Jensen

Recent developments related to petroleum engineering discussed in this paper are: 1. Drilling wells in with oil or the use of chemical compounds or (Imud solvents" for removing rotary mud from wells in order to increase or make possible oil production. 2. Comparison of results of electrical logging methods in locating water, as shown in a recent test on a well in the Los Angeles Basin. 3. A new method for logging formations through casing, known as the Stratagraph. Drilling Wells in with Oil or the Use of Chemical Compounds or Mud Solvents During the time that the California fields showed high gas pressures, the pressure of the gas within the formation was sufficiently great to break down the mud wall or cake formed while the well was drilling. That this did not always occur was demonstrated by the fact that in some of the older fields new wells sometimes had substantially higher initial productions than other wells near by. The explanation seemed to be that some sands were mudded off in the original drilling. Their pressure was then not great enough to break down the mud wall in competition with the higher pressure of the sands, but the situation reversed itself so that a later well benefited by the pressure in these originally weaker sands. As time passed, in wells deeper than 5000 ft. the difficulty of bringing wells on production became more pronounced. This led to a hunt for substitutes, of which a number have been tried. The one that has proved most successful in our experience at Ventura is known as the Nobs solvent. At well No. 1 of the Associated-Ventura Land & Water Co. when it was recompleted in February 1936, about 10 days were spent in trying to bring the well in in the regular manner, but only about 113 bbl. of water could be swabbed from the well, and even this quantity decreased as time passed. The Nobs solvent was spotted in the bottom of the hole opposite the perforations, inverted Guiberson swab rubbers were used on the drillpipe and the hole was down-swabbed in stages, beginning

Jan 1, 1937

By Walter S. Larsh

The Ruth orebody, so far developed, is roughly oval in plan, major and minor axes about 1600 ft. (457 m.) and 1200 ft. (365 m.) respectively, average thickness about 120 ft. (36 m.), and with a general dip of about 15" to the northwest. According to the generally accepted theory, the ore is a secondary enrichment of the porphyry due to leaching in situ by meteoric waters. Copper occurs as chalcocite, chalcocite coating pyrite, and a little chalcopyrite. The leached zone, or capping, covering the ore varies in thickness from 110 to 540 ft. (33 to 164 m.), average about 410 ft. (124 m.). The ore is blue gray in color, and the capping, light yellow to brown. Ore was first discovered in quantity in the workings from the Ruth shaft, now caved. Further development work was done by churn drills, and the outline of the orebody, as stated above, determined in this manner. Drilling is still being carried on. The porphyry area is entirely surrounded by sedimentaries, limestones, and shales; and, in so far as the underground workings have shown, the porphyry itself, the sedimentaries' near the contact, and the country underlying the ore (igneous or sedimentary) is very soft, heavy, and in places swelling ground. All openings have to be carefully and stoutly timbered, and, after once driven, they have to be constantly eased off and repaired. The mine Is at present served by two shafts, the Star Pointer, the main working shaft, a vertical, and the Ingersoll, an incline used for waste and material. The two shafts are about 2600 ft. (792 m.) apart, connected on the 500 level; a connection is now being driven on the 600 level. (Dec., 1917. This connection is now completed.) The 300 level, which is finished, and the 400 level which is nearly completed, are accessible only from the Ingersoll and connections with the 500 level. The 300 level was developed for and mined by the shrinkage stope system, similar to that used successfully in the Ray Consolidated property.

Jan 1, 1918

By A. M. McQueen

Activity in the oil industry in Peru was somewhat above normal in 1928. Probably the most significant feature was the interest displayed in the oriental region in the northeast part of the country (Fig. 1). This region, though little known, has long been considered potentially rich in oil! gold, coal and other minerals, lacking only transportation to make it the country's most valuable source of income. The Standard Oil Co. of New Jersey, through its recently formed subsidiary the Standard Oil Co. of Peru, has acquired various tracts along the Maranon and Ucayali rivers in the neighborhood of the Brazilian border. Standard Oil Co. interests have had geological and surveying parties in this part of Peru since 1921, and as a result of the work done, we understand they have under lease at the present time some 2,500,000 acres of prospective oil lands. Development in the coastal region continued along normal lines during the past year. Production figures for both the International Petroleum Co. and Lobitos Oilfields show a small increase over the last few years. Total production figures since 1924 for the International Petroleum, Lobitos Oilfields and Zorritos companies, only in a minor degree estimated, are as follows: 1924, 7,924,700 bbl.; 1925, 9,138,042 bbl.; 1926, 10,750,676 bbl.; 1927, 10,110,696 bbl., and 1928, 11,969,677 barrels. International Petroleum Co., Ltd. Operations on the La Brea-Parinas Estate during 1928 continued with satisfactory results; nearly all branches showing improvement over the previous year. The average daily production for 1928 was 25,966 bbl., compared with 21,282 bbl. for 1927, an increase of 22 per cent. During the last two or three years, production methods on the company's property have been improved in line with the advance in scientific technique throughout the oil fields of the United States. Extensive investments were made in compressor equipment for handling surplus gas with the result that the gas-lift and repressuring operations are in no small way responsible for the increase in the 1928 production. In addition, the company's three casinghead plants produced 24,847,708 gal. of gasoline compared with 17,240,865 gal. in the previous year.

Jan 1, 1929

By C. E. Cannon, R. C. Craze

This paper discusses the results of a study of reservoir pressures in the Gulf Coast area of Texas and Louisiana, showing the general relation of the reservoir pressure to its subsea depth, as well as excessive reservoir pressures that have been encountered. The latter are particularly important in mud-control work, and the data show why it is necessary to use muds having a relatively high density in many of the deeper wells drilled in this area. Only a comparatively few of the wells drilled in the Gulf Coast that have encountered excessive pressures are discussed, but as far as is known those omitted fall within the range of pressure observed by the writers. Measurement of Pressures The following methods were used to determine the values of the original pressures: 1. Estimation of original pressure from subsequent pressure behavior of fields. This method is not precise, and was used only in a few of the older fields in which better methods of obtaining original pressures were not available. Only normal pressures were determined by this method. 2. Measurement of shut-in pressures soon after completion of the first producing well. With one exception, all pressures measured by this method were normal, this well having a pressure slightly higher than normal. 3. Measurements of pressure in connection with drill-stem tests. 4. Estimates from the maximum hydrostatic head of mud that failed to prevent flow from the high-pressure formations into the hole. This method is not exact, tending generally to indicate low pressures. Normal Pressures All pressure measurements available are plotted in Fig. 1, with original pressure at the water-oil contact as abscissa and subsea depth as ordinate. All producing fields fall close to the solid line, which passes through the origin and has a slope of 0.465 lb. per sq. in. per ft. By way of compari-

Jan 1, 1938

ALTHOUGH the first colonists in the area that is now the United States, whether Spanish, French or English in nationality, were usually keenly interested in the possibilities of mineral wealth, it is a curious and interesting fact that none of them happened upon the mineral deposits that eventually were to make this the greatest mineral-producing country; up to 1800 it would probably have been rated as rather poor in minerals. Spanish explorers traversed the southeastern United States with- out finding the Appalachian gold deposits that aroused so much interest in the early nineteenth century; Coronado sought in vain for the seven golden cities of Cibola; and the important gold deposits of California were not discovered until the political sovereignty of the region had passed from Mexico, which had held it for three centuries. The French also held Canada for nearly two centuries (and the British for another century) without finding the mineral deposits in Ontario and Quebec that now are so important. Though they knew of the copper of the Keweenaw peninsula, the lead ores of Wisconsin and Missouri, and the coal of Illinois in the seventeenth century, these deposits were all too remote for exploitation. In the area held by Great Britain, iron smelting was planned at Jamestown as early as 1619 and was actually begun at Lynn, Mass., in 1643. The industry grew slowly, at first, but had reached considerable importance before the Revolution. Commercial bituminous coal mining began about 1750 in Virginia but anthracite mining in Pennsylvania was not started until 1800. As a result there was naturally little interest in the technical aspects of mineral production here before 1800 by any except the few people who were actually engaged in it. Students of natural science were much interested in minerals, however. The activities of those who rank as geologists are so thoroughly covered in

Jan 1, 1941

By Enrique Touceda

The question as to the proper amount of total carbon that the malleable founder would prefer to have in pig iron for use in the production of air-furnace, white iron castings, must be considered from different angles, that is, whether it is desirable or advantageous from an economic standpoint to use some kind of low-carbon scrap on his mixture, or make use of pig and sprue only. Whereas silicon is the acknowledged scrap carrier in the case of cupola gray iron castings, carbon performs this role for the most part in malleable iron practice, irrespective of the character of furnace used for the production of the white iron castings. In this particular, the advantage lies with the maker of gray iron castings in that the silicon content in pig iron through a regulation of furnace temperature is under very easy control by the blast-furnace manager, whereas he has little or no control over the resultant percentage of carbon, as this is dependent on the quantity of coke in the hearth, and hearth temperature, coupled with the amount of hearth slag and its particular composition. As perhaps more than 95 per cent. of white iron castings are made in air furnaces the following statements are intended to cover that situation particularly: In the malleable process the composition of the hard iron castings (that is determined upon as best suited for the work in hand) is the one factor that must control the composition of the mixture to be used; because if the elements are not between certain definite limits individually and collectively the annealed or finished product will be unsoitable, due, perhaps, to lack of sufficient strength or because it is too hard, to machine easily. The annealed product can be divided into two classes, one of which greatly predominates, that is, by far the largest tonnage is used for machine parts where high strength and ductility are essential requisites, while a far smaller amount, light in weight and thin in section, is used for other manufactured products in which castings of any reasonable degree of strength and ductility have proved satisfactory.

Jan 1, 1927

By Frank Antisell

CERTAIN physical and chemical properties of copper are so intimately related that a change in variation of the physical properties indicates a certain chemical change. The standard specifications of copper of the American Society for Testing Materials are based upon physical characteristics with one exception, namely, the copper contents. The physical standard includes electrical properties, defects in the "set or casting," variation in dimensions, weight, etc. Paragraph 4 of the specifications states, " Wire bars, cakes, slabs and billets shall be substantially free from ;shrink holes, cold sets, pits, sloppy edges, concave tops, and similar defects in set or casting." Shrink holes and concave tops indicate both physical and metallurgical defects; cold sets, sloppy edges, etc., indicate physical defects only; small pit holes may be indicative of either or both physical and metallurgical defects, depending on conditions under which they originated. To the refiner, a copper casting, no matter how made, is known as a "shape," irrespective of whether it is wire bar, ingot, cake, slab, billet, etc. As practically all shapes are cast in an open mold, that is a mold without cope, the surface of the shape cools in contact with the atmosphere and has a coating of oxide. Certain phenomena of the surface indicate the adaptability of the metal for forging or rolling. The writer believes that it is much simpler to produce shapes that are metallurgically correct than those that are mechanically satisfactory. When copper is to be rolled into thin sheets or drawn into very fine wire, the slightest physical defect becomes evident. It is, therefore, of the utmost importance to, consider every characteristic of the shape and ascertain the physical and chemical relationship. Pitch and Set.-The appearance of the surface of the copper when cooled is considered as to its "pitch," or the general contour of the surface of the shape (which may vary from a concave to a convex); and the "set," or the detail appearance of the surface of the shape (the wave-like struc-

Jan 1, 1920

By Richard Divine

IN the Parkes process of extracting precious metals from lead, zinc is added to the molten lead containing gold, silver, copper, and, some antimony. These metals, with the exception of antimony, form an alloy with the zinc by reason of their greater affinity for it than for the lead, and this alloy, being lighter than lead, rises to the top, carrying the precious metals with it, whence it can be removed by skimming. These skimmings are further treated for the separation of the zinc therefrom, and the recovery of the precious metals, the zinc being driven off by heat and again used for another operation. In addition to the zinc that combines with the silver, etc., a certain amount is necessary to saturate the lead, and it is therefore necessary to treat the desilverized lead to free it from this residual zinc. To do this it is heated again in a reverberatory furnace and air or steam is blown through it. This oxidizes the zinc together with a small amount of lead and antimony, leaving the lead free from zinc and antimony, and forming oxides of these metals, which rise to the. top and are skimmed off. This process relates to the separation of the metals in these oxides or skimmings. The skimmings are cooled, crushed, and mixed with carbonate of soda and pulverized oil coke. The mixture is heated in a reverberatory furnace on a bath of lead, to about 1,000°C. The metals are reduced by the coke, the lead and antimony go into the lead bath, while the zinc is volatilized and burned to oxide. This impure oxide is at the present time treated at Omaha by the Hall process of electrical precipitation, making a very pure metallic zinc. It can also be very easily refined by the old Schnabel process of using ammonia and carbon dioxide as a solvent. It seen-is to be in an ideal form for this purpose, and very few changes from the original method are required to obtain the zinc oxide practically C. P., leaving the lead and antimony as residues.

Jan 8, 1914

By d&apos, C. Antonio, S. H. Reichman

In the course of our studies of the annealing behavior of vapor-deposited silver films we have determined the electrical resistivity as a function of annealing temperature for films in the thickness range of 630 to 3240A. Fig. 1 shows the resistivity of the silver films vs film thickness in as-deposited and annealed conditions. The films were prepared by depositing 99.999 pct pure silver from molybdenum boats onto Vycor substrates. Deposition was conducted at a residual pressure of 5 x 10"6 Torr at rates of 20 to 408, sec-'. Thicknesses were determined using a multiple-beam interferometer. During annealing, resistance was measured using the four-probe method. Measurements were made every 5°C during two consecutive anneals to 300°C under a continuous vacuum of 2 x X6 Torr. The heating and cooling rates during annealing were approximately l° and 2°C min-', respectively. Typical resistivity vs temperature curves are shown in Figs. 2 through 4. There is an inflection point evident at 120°C on Fig. 2, the first anneal of a 3240A film. This inflection point was found on all films above approximately 1!00A on both first and second anneals. Below 1400A the inflection occurred at approximately 180°C. Figs; 3 and 4 show the first and second anneals of a 1370A film. The inflection point occurs at 180°C on the first anneal and approximately 120°C on the second. Our interpretation of this phenomenon is based on oxygen liberation from the film surface. It is well-documented that the presence of oxygen on silver surfaces causes a reversible increase in resistivity.1"3 The liberation of this oxygen, for example during vacuum annealing, would therefore cause a decrease in resistivity as observed on Figs. 2, 3, and 4 as a change in slope. This is accounted for by the decomposition of Ag20 on the film surface. The free energy of AgzO becomes positive between 125" and 225°C.4 The thickness dependence of the inflection points can be explained as an orientation effect. The films used in this study were preferentially oriented with their (111) planes parallel to the Substrate.''~ In addition it has been sten that the thinner films, below approximately 1500A, possess a decided "hill and valley"

Jan 1, 1969

By W. P. Dyrenforth, W. E. Horst

Although, separating or concentrating minerals, based on differences in. their magnetic properties has been practiced for years1 the early industrial applications of magnetic separators were involved with the most highly magnetic materials. These early separators were used to concentrate magnetite, separate metallic iron from furnace products, and separate iron and brass turnings. Next, the addition of a pretreatment operation, such as roasting or calcining, to transform certain iron-bearing minerals into a highly magnetic compound that could readily be separated from the altered mineral mixture using existing magnetic separation machines was added to the flowscheme. As the number of magnetic-separator installations grew, steady development of better equipment evolved including the design and implementation of induced magnets having high-intensity fields, These developments of course greatly expanded the field of magnetic separation and made it possible to commercially separate or concentrate very weakly magnetic minerals which previously had been considered as nonmagnetic minerals. A number of different designs of magnetic separators were well developed and the unit operation of magnetic separation was gaining wide acceptance in mineral processing operations when two events occurred that dampened these developments. First, the Mesabi iron range with its direct-shipping iron ore was discovered and placed into operation. This of course significantly reduced the need for magnetic separation to meet the raw material requirements of the iron and steel industry. Second, the advent of selective froth flotation, was so successful in solving many mineral process problems that electrical concentration techniques being developed at that time, including magnetic-separation methods, were either terminated or received low priority ratings. During the past two decades interest has been renewed in the use of electrical concentration methods to solve mineral separation problems. As the direct-shipping iron ore reserves are depleted more emphasis has been placed on magnetic upgrading of lower value iron ore available throughout the world. In addition, magnetic separation techniques have found numerous applications in the non-metallic and industrial minerals industry to supplement froth flotation and thus add to the variety of beneficiation methods available.

Jan 1, 1971

By John Carter Anderson

The theory of a zonal deposition of ores from ascending solutions which were differentiation products of a cooling magma, first propounded by Spurr,l in a measure explained by Lindgren,2 and recently re-emphasized by kemp,3 while perhaps accepted in principle by many mining geologists, so far has not been accepted as capable of practical application in the study and development of ore deposits. From his observations, the writer is convinced that there are laws governing the primary deposition of ores which, when properly worked out, will be of greatest economic value; and that the application of this knowledge to the development of new mines will mark an advance in the mining industry similar to that following the working out and application of the theory of secondary enriehiment. That there has been a tendency to a zonal distribution in the formation of ore deposits, by which the ores of one metal have been precipitated from tile mincralizing solutiolis at a greater distance from the source than those of another, cannot be disputed; and the nature of this zoning in a given deposit or district has been frequently described.4 But that a selection precipitation of the ores of two or more metals, other than lead and zinc, in successive zones may have taken place in a single deposit within limits economically possible of exploration is not generally recognized or admitted.

Jan 1, 1923

By J. D. A. Morrow

This discussion relates to the distribution of coal under the di , of the U. S. Fuel Administration beginning Apr. 1, 1918. At t' L a definite method of controlling and directing distribution was put int effect. Prior thereto, although some of the machinery utilized was in operation, especially in the few weeks immediately preceding' Apr. 1, distribution had not been effectively and comprehensively organized. The writer was called to the Fuel Administration by Dr. Garfield about the first of February, 1918, to assume general direction of the distribution of coal for the Fuel Administration, to develop the general plans, and to obtain practical men to assist in this work and in carrying through the program finally devised. A study of the situation and conferences with the Fuel Administrator and leading men in the business made it plain that it would be necessary to begin at the bottom, measure the undertaking, develop plans to meet the need thus shown, and build an organization to effect the distribution required. This work had to be done under war pressure in the midst of a bad coal shortage. The successful performance of such a task is always primarily a matter of putting competent men in the right places and giving them the power and opportunity to function properly together. In the Distribution Division of the U. S. Fuel Administration, the men who were chiefly responsible for whipping plans into practical form and then for carrying out these plans were A. W. Calloway, of Baltimore, President of the Davis Coal & Coke Co., who served as the Director of Bituminous Coal Distribution; S. Lovell Yerkes, of Birmingham, Alabama, Secretary of the Grider Coal Sales Agency, who assumed general charge of distribution while the new plans and organization were being perfected and then became the Assistant Director of Bituminous Coal Distribution; Warren S. Blauvelt, of Detroit, who was Director of Coke Distri. bution; A. S. Learoyd of New York, Director of Anthracite Distribution, in connection with the Anthracite Committee, consisting of Joseph P. Dickson, President of Dickson & Eddy, Chairman; S. D. Warriner, President of the Lehigh Coal & Navigation Co., and W. H. Richards,

Jan 1, 1920

By J. M. Lovejoy

Tests are described that show that back pressure on flowing wells is a waste rather than a conservation of natural forces. Stop-cocking, however, gives encouraging results. VARIOUS estimates have been made as to the percentage of oil left in a field after the wells have become so small that it is no longer practical to produce them. Engineers have given the matter much study and can substantiate their figures by data taken from fields from the Appalachians to California. The average oil sand has a porosity of about 20 per cent., which gives a capacity per acre-foot of approximately 1500 bbl. The sand thickness in Oklahoma pools averages 20 ft. With 20 per cent. porosity and a 20-ft. sand thickness, the capacity per acre is 30,000 bbl., yet these pools will seldom yield more than 5000 bbl. to the acre. These figures support the theory that at least 50 per cent. of the oil remains in a sand after all known methods to recover it have been used. Certainly we can never recover all the oil, unless in years to come oil becomes so rare and yet so necessary that the price will justify sinking shafts into the abandoned fields and regular mining methods of drifting and stoping. However, with improved methods of production and conservation of the natural agencies of expulsion, we should be able to increase recovery. It is with this in mind that this paper, relating to the effect of back pressure on wells, is presented. Except in the fields where production is caused by hydrostatic pressure, the chief agency for getting, oil out of the sand into the hole is the gas that occurs with the oil. After the pressure has declined, probably gravity also is a factor, but not an important one. With a given amount of oil in a sand and a given amount of gas occurring with the oil, the ratio of gas volume per barrel of oil is the key to the ultimate recovery from that sand. Our efforts should be along lines that will, lower this ratio and make the gas, the agency given us by nature, do its work better and yield more of the oil, of which it is a part.

Jan 1, 1924

Discussion of the paper of HOWLAND BANCROFT, presented at the Salt Lake meeting, August, 1914, and printed in Bulletin No. 91, July, 1914, pp. 1767 to 1769. THEODORE SIMONS, Butte, Mont. (communication to the Secretary*). -While preparing maps and models for use in mining litigations the writer was frequently confronted with the problem referred to in Mr. Bancroft's paper. His chart gives the apparent angle of dip with which a vein should be plotted on a vertical section not at right angles to the strike of the vein. For a quick determination of this apparent angle the writer has used an exceedingly simple graphical method, which he believes may prove helpful to engineers engaged in practical work. It is submitted, not as a criticism of Mr. Bancroft's paper, but as a means of solving the same problem when no chart is available and when calculations would consume too much time. The writer's method requires merely a few lines marked off on a piece of tracing cloth, as shown in Fig. 1: Draw line be on any convenient scale. At b erect a perpendicular, ba. By means of a protractor cut off on ba a number of angles within the probable range of variation of dip, so that a line connecting a and c, for instance, forms an angle of 60° with be, etc. With b as a center and be as a radius, draw a circle through c. This completes the tool for solving the problem. Fig. 2 represents the line of strike of the vein and db the trace of the vertical plane on which the vein is to be plotted with the apparent angle of dip. A° is the angle which this plane makes with the strike. Fig. 3 shows the application of the method: Place line cb of tracing over line db of Fig. 2 and move fore and back until line of strike becomes tangent to the circle. Connect d with the point (a) that marks the true angle of dip as found by measurement in the mine (60° in the case illustrated). The angle adb is the apparent angle of dip (C°) to be used in the vertical section. Proof.-As stated in Mr. Bancroft's paper, the apparent angle of dip is: tan C° = sin A° tan B° (1)

Jan 12, 1914

By Alfred Fisher

CONSERVATION of mine timber is becoming in-creasingly important, and the consumer is en-couraged to use treated wood to permit longer life of mine timbers, and attempts are also made to substitute other material for wood. The great diffi-culty in substituting metal and concrete props for wood is the inability of these to give yielding resistance to roof pressure as wood supports do. In Europe, where mine timber costs are somewhat more important than in America, many designs of steel props have been tried, but have been unsuccessful, chiefly on account of inability to give yielding resistances. A metal pit prop that gives the desired effect has been extensively used in European mines and has caused a considerable reduction in accidents from falls of roof. Where mining operations have been sus-pended on account of strikes, conditions were found to be much better where such props were used instead of wood props, and machinery, which would have been destroyed by roof falls had wood props been used, was protected by the use of these yielding metal props. As this prop is adjustable, all the work of adjusting and transferring long props through narrow ways is done away with. It can also be drawn with greater ease and safety than wooden props; when properly used it is practically indestructible. European users have reported savings as against wooden props as high as 80 per cent. It gives audible warning of its working because the sliding action takes place in minute jerks. As the prop yields gradually to pressure its force is taken up by friction between the H sections, and this movement progressively increases the resistance of the prop to the increasing roof pressure. In the early development of the prop, it was designed with two steel members a and b of standard H steel sec-tions of equal dimensions provided with guide claws a' and b', held in frictional contact against each other by two differential wedges, f and g, and a floating link, e. In setting up the prop its two members are drawn out to the required length, the loose wedge, g, is then fitted into the space between the left-hand roller of the link d and the lower member of the prop b, and tapped suf-ficiently tight to prevent any relative movement of the two members from taking place prematurely. The prop is then raised to its intended position and secured in the usual way.

Jan 8, 1927

The passing of Benjamin Bowden Lawrence in January, 1921, was a distinct loss to the engineering profession. Mr. Lawrence had a genius for reviving abandoned mines and developing them into substantial producers. A notable example of his work in this line was the Dives-Pelican near Georgetown, Colo. While on an exploring expedition in 1888, he examined this old mine and was convinced that bonanza ore still existed there. He located the owners of the property, and induced them to place sufficient capital at his disposal to enable him to re-open and explore this mine. So confident was he of the outcome that he undertook this work on a profit-sharing basis without salary. Within eighteen months the old Dives-Pelican was operating profitably, and for the following ten years it paid very substantial dividends. The late Theodore N. Vail was one of the owners of this old mine, and many years later, at a dinner given to Mr. Lawrence by the Alumni of Columbia University, Mr. Vail told the story of the resuscitation of the Dives-Pelican by Mr. Lawrence, and declared that the dividends he himself had received provided a large part of the funds that made possible the realization of his dream of establishing the long-distance telephone in this country. The E1 Cobre mines at Santiago de Cuba also owed their renewed life to Mr. Lawrence. Under his management, these mines produced and shipped several million pounds of copper per year. He was for several years consulting engineer for the Kerr Lake and other silver mines in the Cobalt region; the Kerr Lake became famous as a silver producer. Mr. Lawrence spent more than twenty years of his life in the mining camps of the West. He was but twenty-one years of age, and only a few months out of college, when he was appointed manager of the great Chautauqua Lode (a silver mine) located on Glacier Mountain near Montezuma, Colo. Here, isolated in the mountains for several months each year by ice and snow, he worked for five years to make these mines Pay. He possessed unusual breadth of vision and human understanding; he had ''personality plus," and when he opened an office in New York City as consulting engineer he quickly rose to an enviable position in his profession. Young engineers worked with enthusiasm under his guidance. He carefully selected his men, discussed fully with them the plans and policies to be pursued, then left them free to accomplish results in their own way. This attitude developed individuality and resourceful-

Jan 1, 1922

The cables brought the news last spring that the Institute had lost by death one of its most distinguished foreign members, Hjalmar Sjogren of Stockholm. For thirty-one years, Professor Sjogren had been one of our number. He was elected in 1891, joining the Institute at the time he was in the United States, in attendance at the Fifth International Geological Congress, which was held in Washington in the late summer of that year. Professor Sjogren was once more in America in 1906 and again in 1913, and on both of those visits his friends in New York had the welcome opportunity of extending courtesies to him. He was thus well known to a wide circle in our membership. His keen interest in the geology of iron ores brought him in touch with the many Americans who have studied them and who have been active in the important productive districts which he visited. Our Transactions contain (Vol. XXXVIII) one very important paper of seventy pages on the Geological Relations of the Scandinavian Iron Ores, which he contributed. Sten Anders Hjalmar Sjogren, to give his full baptismal name, was born June 13, 1856, and was the son of Anton Sjogren, a mining engineer, at the time in charge of the iron mines at Persberg, in the east and west iron-ore belt of central Sweden, about 160 miles west from Stockholm. The Persberg orebodies yielded magnetite and specular hematite from schists, with which limestones. were interstratified as well as the peculiar Swedish rocks called "halleflinte." The mines were also well known to collectors and students of minerals. While Hjalmar Sjogren was yet a lad, his father was advanced to the superintendency of a number of famous mining localities in this same district of Wermland. Paisberg, famous for its native lead, was one; and two others, Langban and Nordmarken, were among the most prolific sources of interesting minerals in all Sweden. In several localities, the pre-Cambrian limestones had obviously experienced the recrystallizing influences of intrusive igneous rocks and had been charged with the so-called "contact" minerals, which have found their way to the museums of the world. Anton Sjogren, the father, was a keen mineralogist and Hjalmar, the son, grew up in a favorable environment for receiving training and enthusiasms of the same sort. One is not surprised, therefore, to find Hjalmar Sjogren, in the long run, turning to mineralogy and geology as his final career.

Jan 1, 1923

By H. K. Shearer

There were no important developments in the oil and gas industry in South Arkansas during 1935. Oil production, totaling 11,138,340 bbl., continued the decline that has been normal since 1925, but the decline from 1934 was only 278,600 bbl., or 2.5 per cent. The principal decline was in the Smackover field, while only the Champagnolle and Garland City fields showed notable increases. More wells were drilled than in any recent year, with a total of 123 completions. There were 44 oil wells, with a total reported initial daily production of 10,013 bbl., or an average of 227 bbl. per well. Two small gas wells were completed in Union County, where the gas is used locally for pumping and field operations. There were 77 dry holes, of which 28 were in or near oil fields and 49 were wildcats. Active drilling oper-at'ions declined from 65 at the beginning of 1935 to 41 at the end. Most of the drilling was done during the first part of the year, espr-chially (luring the flurry caused by the discovery late in 1934 of the "Taylor" sand production in the Champagnolle field, but the producing area was soon outlined. In November, 1935, the J. E. Crosbie, Inc., NO. 1 Sullivant in sec. 12, 17s. 14W., producing 560 bbl. per day at 3175 ft., opened a new sand lens in the eastern part of the field. The Camden "oil field," discovered in the last week of 1934, remained a one-well field, although four offset tests were drilled, besides a number of others in the immediate vicinity. Several interesting deep tests were drilled during the year, which added a great deal to the general knowledge of the subsurface formations and the structure of south Arkansas, but were not particularly encouraging as to prospects for the very deep production. First, the H. L. Hunt, No. 15 E. F. Gregory well in sec. 10, 17S., 14\W., in the Champagnolle field, was drilled to a depth of 6911 ft. It pene-trated red beds for 2982 ft., from 2943 to 5925 ft., mostly if riot entirely of Lower Cretaceous age. There was some anhydrite in the last 135 ft. of red beds. This was followed by 890 ft. of limestone, probahly Permian, and the rock salt was struck at 6815 ft. The salt is now generally conceded to be of Permian age. Finding salt in this well strongly indicates

Jan 1, 1936