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By A. S. Adams

A glance at the list of papers1 that have been published since 1920 on the general subject of flotation suggests the variety of ideas that exist regarding the underlying cause of the phenomenon. Among these ideas, we find several coherent theories, but none that adequately and completely explain the phenomenon. Ralston2 and Bains3 suggested an electrical theory which has to do with the attachment of mineral particles to a bubble by the attraction of unlike electrical charges. This theory has its root in the fact that a bubble of air in pure water is electrified in such a way that the surfacc is negatively charged while the body of the water is positively charged. This result, which was first discussed by Helmholtz, also obtains when the water contains anything except a high concentration of hydrogen ions, or ions which are trivalent or tetravalent. The theory also holds that the mineral particles have positive charges on their surfaces, and so there is attachment between bubble surface and mineral particles by the old law of electrostatics, which states that unlike charges attract. Contact Angle and Oil Attraction The contact angle—the angle formed by a fluid-fluid boundary when both are in contact with a solid-—has been indicted several times for complicity in the phenomenon of flotation. This angle is supposed to indirectly measure the surface energy of a solid. Thus if we have two fluids in contact with a solid, we may express the difference between the two fluid-solid tensions as equal to the fluid-fluid tension times the cosine of the angle between the two fluids.4 If the two fluids are in contact with the solid, this is, no doubt, an excellent way of establishing relative surface energies. However, in flotation, we deal with substances which are not wetted by water. What assurance have we, then, that the angle

Jan 1, 1928

By Albert F. J. Bordeaux

This paper briefly describes the general outline of cyaniding silver-ores in Mexico, with special reference to personal experiments made in the Temascaltepec district. The most important papers on the subject deal with cyaniding gold-silver ores, the gold predominating in value, so that the treatment is nearly the same as for gold-ores, the losses of silver being considered of little importance. I describe here the treatment of silver-gold ores containing very little gold, which is more general in Mexico than elsewhere. The cyanide treatment, which was so successfully applied to gold-ores, did not succeed immediately with silver-ores on account of their varying composition. Gold occurs in nature usually in the native state, while silver occurs generally in combination with sulphur (argentite), and various combinations of sulphur, antimony, and arsenic. In former times there mas a complete difference in the treatment of gold-ores and silver-ores. Amalgamation, which was successful with gold-ores, was generally inadequate with silver-ores. The usual treatment in Mexico for silver was the patio process, the theory of which was satisfactorily explained only quite recently by Mr. Ortega and others. General Outline of the Cyanide Treatment. The general tendency of the present practice is to slime the silver-ore as much as possible, and in order to obtain a higher efficiency, with less loss of cyanide, and greater speed, the following lines are observed: 1. Crushing by stamps with 30- or 40-mesh screens, then crushing by Huntington or Chilean mills, through 60- or 80-mesh screens. 2. Concentration upon vanners.

Jan 1, 1910

By R. S. Archer

IN the microscopic examination of aircraft-engine parts made of heat-treated alloy steels, the writer has been forcibly impressed by the failure of the usual etching processes to disclose any but gross defects in heat treatment. It seemed particularly desirable to bring out the grain size of the steel, which is indicated in the ordinary etching processes chiefly by the change in orientation of structure from grain to grain. After various attempts, a fairly successful method has been found, which is here presented in the hope that it may be of use to those who have occasion to examine these steels in the heat-treated condition. The specimens worked with have been mostly chrome-nickel steels heat treated (that is, hardened and tempered) to a Brinell hardness of around 300. A few experiments with other specimens will be referred to later. Briefly, the method employed consists in etching the steel about 10 min. in a fresh solution of picric acid in ethyl alcohol, and then rubbing off the smudge of carbonaceous matter on moist broadcloth. Different samples of almost identical analysis; heat treatment, and physical properties (including resistance to impact) respond quite differently to this treatment. In some, the grain boundaries are developed quite readily, while iii others, especially ill those whose grain is unusually fine or in which the final hardening heat, has not quite obliterated the previous crystallization, the results are more obscure. The exact time of etching to secure the best results also differs for various samples, and the greatest success is usually attained by a process of "tinkering." Such a process is illustrated in a series of micrographs, the first six of which were taken at a magnification of 300 diameters.

Jan 1, 1919

By Orson Cutler Shepard

RECENT research work in the flotation concentration of minerals has been concerned mainly with flotation reagents and the mechanism by which collecting reagents are held to the surface of certain mineral particles. The fundamental question of why air bubbles cling to properly prepared mineral surfaces is usually dismissed with the statement that the surface is air-avid or water-repellent. In my article in MINING AND METALLURGY for June, 1932, I showed theoretically that surface tension relationships govern bubble attachment in Rotation. This explanation has not been accepted by many; probably be¬cause the difficulty of measuring solid-solution surface tensions prevented obtaining experimental evidence. If the surface tensions involved in the system [solution, mineral, air bubble] are responsible for attachment of the air bubble to the mineral, any change in the surface tensions should cause a corresponding change in the attachment of the air bubble. An example in which the mineral-solution surface tension could be varied was found with mercury. When mercury is in contact with solutions of certain electrolytes the surface tension at the contact of mercury and solution can be altered by electrical polarization of the mercury. The surface tension rises to a maximum as the mercury is given an increasing negative potential and then decreases with further increase in potential. The theoretical relation between the surface tensions and the attachment of an air bubble is given by the following equation:

Jan 1, 1936

By R. J. Wasilewski

The variation of elastic modulus with terrzperature between -150° and 600°C has been investigated. Compounds close to equiatomic cornposition exhibit very low modulus values and very high damping near room temperature. The modulus rises steeply with both decreasing and increasing temperature. The modulus minimum and the high damping are believed to be connected with a martensitic transformation of TiNi. In bulk material this transition takes place slightly above room temperature quite rapidly and reversibly, with a hysteresis of some 30°C, depending on the Ti:Ni ratio. Oxygen impurity affects the reaction time. THE inter metallic compound TiNi has been reported to exist in an ordered CsCl (B2) structure,l-6 the homogeneity range varying rather markedly with temperature.7 Some investigators reported this compound to decompose peritectoidally to Ti2Ni and TiNi, between 650° and 800°C,3 or below,',g the latter workers also suggesting the decomposition to be strain-sensitive. Purdy and Parr were the first to report a structural transformation to a new, possibly hexagonal, structure at 36°C,7 a temperature indubitably too low to allow the significant amount of diffusion necessary for a peritectoid reaction. Mechanical-property investigations of compositions close to TiNi just above room temperature have qualitatively shown remarkable anomalies, particularly with respect to clamping,' and to a "memory" effect, that is, plastically deformed material returning to its original shape on being heated through the "decomposition" temperature.9 The original explanation of this effect—based on the apparent experimental observation of Ti2Ni or TiNi, formation in the material subjected to tensile or compressive stresses, respectivelp—does not appear plausible. It appeared more probable that the change involved may be a martensitic, diffusionless structural transformation, similar to those observed in other B2 structures such as 0 brass,'' AuCd,ll and AuZn.12 The existence of such transformation has been established recently,', although the symmetry of the low-temperature structure is not yet known. The present paper describes the elastic modulus and damping behavior of polycrystalline TiNi in both structures. EXPERIMENTAL METHOD 1) Specimens. All the specimens to be investigated were prepared from premelted electrolytic nickel and iodide titanium by nonconsumable arc melting and casting in a water-cooled copper mold. The cast billets were canned in mild steel, extruded, and swaged to approximately 0.375 in. diam. The cans were then removed by pickling or machining. Preliminary material balance checks indicated no significant weight losses on melting (less than 5 mg on a 50-g button); hence nominal compositions have been used throughout. In agreement with previously reported observations7 no single-phase material was obtained at—or close to—Ti 1.00 Ni1.00 a small amount of finely divided second phase always being present. It was found that most of the oxygen impurity was associated with this minor phase, which was identified as oxygen-bearing Ti2Ni—possibly Ti,Ni,O. The amount of this phase—at any given Ti:Ni composi-

Jan 1, 1965

By Edward Saibel, W. T. Lankford

DURING the course of an investigation of the plastic flow of aluminum aircraft sheet under combined loads, several problems arose in which analyses of the conditions leading to unstable plastic flow were needed. In order to provide these analyses, and in the hope of attaining a better understanding of the general problem of unstable plastic flow, the present study was undertaken. It is well known that unstable plastic flow is associated with a form of mechanical instability frequently observed during the plastic deformation of ductile metals. This instability is characterized by the fact that, at its onset, plastic straining will proceed at a constant magnitude of the externally applied forces. It is further typical that the resulting unstable flow is generally accompanied by the formation of a neck, a local bulging, or some other form of heterogeneous deformation. Perhaps the most familiar example of unstable plastic flow to the metallurgist is the formation of the neck in the ordinary tension test. It is well known that in this test most metals exhibit a maximum in the externally applied load, followed by the process commonly referred to. as "necking down." Instability in the simple tension test has been frequently discussed and numerous investigators 1,2.3,12 have derived the criterion for instability in terms of a critical rate of strain hardening. It is the purpose of the present study to extend the criterion for unstable flow to the more general case where the body undergoing flow is subjected to combined loads. It is hoped that the problems considered will provide a more consistent picture of the general features of this important form of mechanical instability. The most practical implications of instability in plastic flow arise in connection with sheet metal forming operations. In the formation of a great many sheet metal parts, the deformations are produced primarily by stretching. If the conditions which lead to unstable flow are fulfilled in such a formation, and if the resultant instability leads to a pronounced localization of flow, then the useful limit of ductility of the material will have been reached. It is also essential that the effects of instability be taken into consideration in any study of the plastic flow and rupture of metals under combined stresses. In general, when unstable plastic flow is initiated, straining becomes localized, the geometry of the test specimen changes, and the state of stress in that portion of the specimen undergoing plastic flow is no longer under external control. In many past studies of the effects of combined stresses on flow and rupture, account has not been taken of the fact that, although a given test may be started under constant

Jan 1, 1947

By B. H. Dunshee

This paper is not intended to be a technical discussion of square-set framing as used in mines, but merely a short description of the different kinds of framing that have been used in the Butte mines, and what has been decided upon, after years of practical experience, as being the best, taking into consideration the physical condition of the veins and country rock, and also the supply of timber available for mining purposes. Butte is, essentially, a square-set district. Virginia City, Nev., was the first mining camp to use this method of timbering, and to Philip Deidesheimer, who went to the Ophir mine in 1860, is given the credit of solving the problem of square-set framing, where large bodies of ore were stoped and the timbers were supposed to hold the ground from caving without any filling. That he did his work well is shown by the fact that the main features of his framing are in use to-day. In the Butte mines the conditions are such that this method of timbering is generally used. We do not, of course, depend upon the timbers any more than is necessary. The worked-out stopes are filled with waste rock as close behind the miners as possible and not interfere with mining operations. The waste rock is obtained from development work on the different levels or from the surface. In the earlier days of mining in Butte there were numerous independent companies and naturally there were different ideas as to the best way to frame the square sets, although the general features were the same. Timber was abundant for mining purposes and the common practice was to use sawed lumber, generally 10 by 10 in. or 12 by 12 in. square. Some of the mines used for girts 6 by 10 in. or 8 by 12 in. timber, depending upon whether they used 10-in. square or 12-in. square timber for posts and caps. This avoided the necessity of framiug the ends of the girts, and also required less timber for the

Jan 1, 1914

By B. B. Zavoico, J. G. H. Crump, P. P. Gregory

West Texas was the scene of greatly increased oil activity during 1937, producing 75,743,000 bb1.l in that year as compared with 61,901,-000 bb1.2 in 1936, an increase of 22.36 per cent. The annual total of wells completed increased from 15863 in 1936 to 28062 in 1937, an increase of 76.92 per cent. Of the total completions in 1937, 2464 were oil wells,2 11 gas wells2 and 331 dry holes.2 The marked increase in the number of oil wells completed in West Texas during 1937 had a substantial effect upon the daily average production per well, which decreased 20.84 per cent from December 1936, when a total of 5310 wells3 produced 5,236,467 bbl.3 for an average of 31.81 bbl. per well per day to December 1937, when 7571 wells2 with a total production of 5,910,257 bb1.2 averaged 25.18 bbl. per well per day. Drilling blocks and checkerboard acreage were being acquired following geophysical work in the northern end of the Permian Basin area, composed of Bailey, Cochran, Hockley, Yoakum and Terry Counties, presaging extension of active development northward. During 1937, at one time 30 geophysical crews were working in West Texas, and an average of 15 to 20 crews was active in this area throughout the year. Discoveries Wasson-Denver Field.—Wasson-Denver field in Gaines and Yoakum Counties was the outstanding field discovery of the year. Production is from porous limestone found at about 5000 ft., and an average well is good for from 300 to 500 bbl. of crude oil per day through 3/4-in. choke. The discovery well was drilled by A. G. Carter and others on the Wasson Ranch, Gaines County, and the field has since been extended into Yoakum County. At the year's end 21 wells had been completed, producing

Jan 1, 1938

By D. E. Spiller

Introduction Precious metals recovery from ore can generally be accomplished using gravity concentration, flotation, and/or hydrometallurgical (leaching) techniques. The objective of this paper is to show why gravity concentration can be an important part of recovery systems that employ leaching as the primary unit operation. A brief discussion of modem gravity concentration equipment is also presented. Discussion Gravity concentration of ores has generated increasing interest in recent years. Reasons for this interest include: • Gravity concentration is environmentally attractive. There is little or no use of reagents. Hence, it is relatively nonpolluting. • The cost of cyanide has continued to increase. Therefore, cost savings may be realized whenever leaching feed tonnage can be reduced by preconcentration. • Compared to flotation and leaching, gravity equipment costs are low per processed ton. Field installation costs for gravity circuits usually are less because many' units are supplied as self-contained modules. Also, the cost required to supply services, particularly power, to a gravity plant site are also less. In situations where preconcentration at coarse particle size is applicable, significant grinding equipment savings may be possible. • Gravity circuit operating costs are also relatively low compared to typical flotation and leaching circuits. Reagents, power, maintenance, and manpower savings in a well-engineered gravity plant may be realized. Again, if grinding is reduced, significant power and steel (media and liners) savings are possible. •In recent years, more efficient gravity concentrating devices have been developed. Benefits to Precious Metal Leaching Gravity beneficiation can complement precious metal leaching in two ways. First, the recovery of coarse liberated values before leaching may reduce leach time requirements and may reduce reagent consumption. Second, gravity preconcentration can reduce the size of a leach plant by decreasing the quantity of material to be leached. Coarse gold and silver have been shown to leach rather slowly. Kameda (1949) and Habashi (1967) have investigated the kinetics of cyanide leaching systems. They concur that in a heterogeneous reaction, the rate of gold and silver dissolution is directly proportional to the surface area. Thus, the instantaneous rate of dissolution for spherical 0.37 mm (400 mesh) gold is theoretically -25 times faster than for the same amount of gold at .841 mm (20 mesh), based on data from Fuerstenau, Chander, and Abouzeid (1979). Conversely, coarse liberated, +.841 mm (20 mesh), gold is more readily recovered by gravity concentration than is fine, -.037 mm (400 mesh) gold. Therefore, it is apparent that the two recovery systems complement one another. Figure 1 data demonstrates the potential synergism. A sample of - 3.327 mm (6 mesh) Nevada gold-bearing ore was cyanide leached using conventional bottle-roll test procedures. Gold extraction was determined as a function of leaching time. A second sample split from the same leach feed material was hand jigged to remove a coarse heavy mineral fraction, including virtually all of the +.210 mm (65 mesh) liberated free gold. This second sample, with the coarse gold and heavy minerals removed, was subjected to an identical cyanide leach procedure. Figure 1 presents the resulting comparative extraction data. Note that the percent gold extraction for the sample containing no +.210 mm (65 mesh) free gold includes the coarse gold recovered by gravity. The data show that the sample containing coarse gold required about 72 hours of leaching time to achieve 80% extraction. This compared to about 22 hours of leaching time for 80% gold recovery from the sample that contained only -.210 mm (65 mesh) free gold. Thus, there was a 69% reduction in leaching time. The improved extraction data is not wholly attributable to coarse gold removal, but rather it was the combination of gold removal and rejection of other heavy mineral cyanide consumers or leach retardants. Further investigation was not warranted at this time. Preconcentration is the second manner in which leaching systems can benefit from gravity concentration. The premise is that preconcentration can reduce the quantity of leach feed, which, in turn, may reduce leaching costs. Figure 2 presents preliminary data developed by CSMRI for US Minerals Exploration (USMX). Centennial Exploration Inc., in agreement with USMX, is proceeding with evaluations to determine the suitability of various processing schemes for recovery of gold values from the Montana Tunnels property. The data shows how the ore can be preconcentrated by gravity techniques to result in a reduced feed tonnage to secondary extraction techniques, presumably flotation or cyanide leaching. Testing has shown that Reichert cones, followed by treating the cone concentrate on spirals, can deliver about 88% gold recovery in about 13% weight, that is, 87% weight rejection. Consequently, fine grinding and reagent costs are attributable to only 13% of the plant feed rate. Cost data is not yet available, but the potential exists for significant cost savings.

Jan 1, 1985

By J. W. Pugh, Sam Leber

Single crystals of tungsten were made and deformed in tension at 3000°C. The slip traces so formed on these crystals were analysed to determine the apparent slip system. Results indicate that deformation occurs in the<III> direction on planes of maximum shear stress. This determination agrees with the early work of Taylor and Elam on other body-centered cubic crystals at lout temperatures. SLIP in face-centered cubic and hexagonal close-packed metals has consistently manifested itself in straight traces which indicate that glide takes place on planes of highest atomic density and in directions of closest packing. The slip traces observed on body-centered cubic metals are, on the other hand, frequently branched and wavy, and indicate that while glide takes place in the direction of closest packing, it does not necessarily choose the plane of highest density. The early work of Taylor and Elam1 4 indicated that glide took place in the close-packed direction on planes close to those defined by the maximum shear stress. Subsequent investigations have tried to rationalize these observations in terms of an elementary process on the close-packed planes (110). For example, Elam5 and Grenin~er&apos; have suggested alternate glide on nonparallel (110) planes with the observed result that the summation of these glides results in a trace which defines some plane other than{110). Madden and chen7 have recently reviewed the phenomenological and theoretical aspects of noncrystallographic slip. More recently Koehler&apos; has presented a model of dislocation propagation which permits another rationalization. He indicated that dislocation loops are transferred from one glide plane to another by double cross-slip of screw segments. It is reasonable to assume that, on the average, such transfers may result in a trace which approaches the plane of maximum shear stress. The work described in this paper will show that

Jan 1, 1961

By William J. Millard

The Island of Trinidad has much the same geological history as the continent of South America. There are present in this area Cretaceous, Tertiary and Quaternary rocks, which were deposited in a basin covering eastern Venezuela and Trinidad, very much as rocks of the same age were deposited in the Maracaibo Basin in western Venezuela. Along the north coast there are metamorphosed and semimetamorphosed Cretaceous rocks which are found as semicrystalline limestone, schists and quartzites, etc. Both the Cretaceous and Tertiary rocks are petroliferous and are responsible for the production of oil in Trinidad and eastern Venezuela. The geological column in the oil-bearing region of Trinidad is shown below.

Jan 1, 1931

By A. Patton

Introduction THE use of roll scale in the Bessemer process dates back, to the "best of our knowledge, at least 20 years. It was first used by the Ohio Steel Co.; Youngstown, Ohio (now the Ohio Works of the Carnegie Steel Co.) under the direction of Sam, MacDonald, Superintendent of the Bessemer Department at these works. Two 10-ton vessels and one blowing engine capable of blowing one heat at a time were employed. The object of using the scale was to -shorten the length of the blow; or in other words, to increase the production with the same equipment. Various means were tried out for introducing the roll scale into the bath of molten iron: It was shoveled into the vessel before the heat was charged, so that the metal would flow over the scale; it was shoveled into the bath after the vessel was turned up; it Was dumped into the empty iron ladle by the wheelbarrow-load, and at times wars dumped on top of the molten metal in the iron ladle. But the practice of introducing the scale into the iron ladle had to be abandoned on account of danger from explosions and of skulling the -ladles. It was soon learned that the proper place to charge the scale was in the empty vessel, so that when the molten iron was poured into the vessel it flowed over the scale, causing a considerable reaction to take place before the heat was turned up. Eventually, cylindrical chutes similar to those now in use were installed. Into these chutes the scale is dumped and carried into the empty vessel. Before this convenient means of introducing the scale was adopted, the Ohio Works had satisfactorily demonstrated that roll scale would increase production, by blowing 107 heats in one 12-hr. turn (1,087 tons) with one blowing engine, blowing one heat at a time; whereas, prior to the use of scale, the best practice at these works was about 80 heats under the same conditions.

Jan 2, 1917

By D. L. Pentz

The use of "probability" methods in slope stability analysis has been practised by geotechnical engineers for some time. This paper questions whether the term probability has been properly used since in many cases the term is used in a classical statistical manner only to describe frequency distributions of data. This paper proposes a definition of the term probability which includes the engineers&apos; subjective state of confidence for all critical parameters. Such parameters may include the slope stability model, undetected structural features, strength, groundwater pressure distribution, and geological framework. This process does not make a "better" analysis but it does force the geotechnical engineer to state his opinion in such a manner that others can understand and if necessary, criticize the assumptions. Further, this technique forces the question, "What impact would failure of a slope have on the production schedule or costs of a mine?" The level of risk taken in adopting a particular slope design strategy in a mine is not a question of what Factor of Safety should be selected but, rather, what trade-offs result from steeper slopes and the associated costs of failure. This paper also presents several simple probabilistic techniques which, though widely used in other fields have been all but ignored in geotechnical slope stability analyses. These include the use of stratified sampling to optimize Monte Carlo uncertainty approaches, and the use of simple functional approximations rather than complex stability models in probabilistic analysis. The author presents a case example of this technique and discusses the results in comparison with more traditional methods.

Jan 1, 1983

UNDER the same justification that I spoke to you in the preceding chapter on crystal and some other gems, I can now speak much better and with much greater reason of glass, since it is one of the effects and peculiar fruits of the art of fire. Every product that is found [41v] in the interior of the earth is either stone or metal or one of the semiminerals, and glass, as is seen, resembles them all, although in all respects it is dependent upon art. Therefore it seems to me that before coming to the discussion of the arts themselves, I must treat of this very beautiful composition created by art and number it with the semiminerals. Thus in this chapter I shall speak to you of glass, not as a proper semimineral, nor yet as a metal, but as a fusible material that is almost made mineral by art and by the power and virtue of fire, born from the speculation of good alchemistic savants, through whose efforts it imitates. the metals on one hand and the transparency and splendor of gems. on the other. Certainly it is a very beautiful thing and one that should not be left buried in silence, in consideration first of how great a thing art has been, able to discover, and then because its beauty makes it such a pleasing thing for making drinking. glasses and an infinite number of other ornamental things that satisfy the desires of man. I shall begin, then, by telling you, to the credit of the alchemists, how I believe that this thing was found through their desire to make gems; for when they could not bring them to perfection (as also happened with the metals) they made this beautiful and attractive product, glass. However, Pliny says that it was found by chance in Syria at the mouth of the Belus River by certain merchants who were driven there by the fortunes of the sea and forced to stop and disembark there for a time in order to eat. In cooking the food they saw the rocks of that place converted into a flowing, lustrous material. And as they thought about this, it seemed beautiful to them, and when they went away they carried some stones and plants with them. Thus they gave beginning to glass making. But now leaving this discussion it does not matter how it may have been discovered, whether by merchants or by ingenious alchemists. Art is that which has given it being, through many experiments and by addition

Jan 1, 1942

By J. B. Stubbins, D. F. Coates, K. L. McRorie

Twenty-two pit slides that occurred in two Canadian open pit mining properties are analyzed. Information on the results of laboratory tests of the rocks and a brief description of the geological environment are also presented. One deduction from the study is that slides seem to be predictable by using established theory. This corroboration indicates that, contrary to normal mining practice, the appropriate slope angle should vary with the height of the wall. In addition, if the general ground water level around an open pit can be reduced, the appropriate slope angles of the walls could then be increased by a determinable amount. The ultimate objective of these investigations is to determine the relationship between the percentage probability of failure of any slope designed with specific strength paraheters. With this relationship it would then be possible to determine optimum slope angles. Because of changes in various economic factors, open pits are now being mined to much greater depths than previously. The need to keep stripping ratios low without endanrrerine.-- lives and equipment provides a strong incentive to determine the maximum practicable wall slopes. Applied research work is currently being conducted to establish the methods for analyzing optimum slopes.

Jan 1, 1963

By Henry M. Howe

MY attention has been drawn within a few days to a series of articles in Volume XVIII of the Engineering and Mining Journal, 1874, by Mr. J. A. Church, in which it is stated, among other

Jan 1, 1875

By Oliver B. Hopkins

The Peruvian production increased over 3 million barrels from 1933 to 1934—from approximately 13¼ million barrels to over 16¼ million barrels—bringing the cumulative production of the country up to 171 million barrels. Most of this production, as well as most of the increase in 1934, came from La Brea-Parinas Estate, the property of the International Petroleum Co., Limited. In 1932 Peru stood eleventh among the oil-producing countries of the world, but in 1933 her production exceeded that of Trinidad, Argentine and Colombia, which placed her in eighth position. In 1934 Peru&apos;s production was exceeded by that of Colombia by about one million barrels, and by that of the Argentine by about 1½ million barrels, thus placing her in tenth position. After several years of relative inactivity in drilling and exploration there was a noticeable increase during 1934 in both of these lines of activity. Oil Fields La Brea-Parinas Estate.—Production on the La Brea-Parinas Estate. reached a significant total of 85,080 bbl. as early as 1891. It increased to over one million barrels in 1912, and to over 10 million barrels in 1929, and in 1934 it reached an all-time high of over 14 million barrels. The total production from 1890 to 1934 was 133,784,609 barrels. Practically all the drilling on the property has been done with cable tools, but during 1934 three strings of rotary tools were introduced. One was a heavy outfit for drilling a deep test and the other two were lighter outfits for deepening wells in the newer section of the field, where the gas pressure was too high to permit safe drilling with standard tools. During 1934 a total of 28,127 ft. was drilled, 66 wells were deepened, and 6 new wells were completed. At the end of the year 2844 wells had been drilled on the Estate, of which 1814 were still productive. The remaining 1030 wells represent abandoned producers or dry holes. The total area that has been productive up to the present time is estimated at 13,369 acres. An interesting article on the various phases of operations of the International Petroleum Co. was written by Arthur Iddings and published in The Oil and Gas Journal (Dec. 27, 1934).

Jan 1, 1935

By Oliver B. Hopkins

Peruvian production for the year 1935 amounted to 17,064,879 bbl., a record amount for any year, bringing the cumulative production of the country up to 188 million barrels. The 1935 figure is an increase of 785,769 bbl. over the 1934 total. The property of the International Petroleum Co. contributed 636,812 bbl. of this increase, and the Lobitos property 158,625 barrels. Exploration work in the country was again active, with attention focused on three areas, the Huallaga River, Lake Titicaca and the Coastal Zone of the Province of Tumbes. It is reported that in the Huallaga River area the Selden Breck Construction Co. has completed geological and engineering studies on its Pachitea River concessions and has ordered a drilling rig. In the Lake Titicaca region further studies in the vicinity of Pusi were made by Government geologists. During the period from 1906 to 1915, the Pirin anticline in this area produced 285,936 bbl. of low-grade crude. The Government holds 120,000 hectares of reserved lands in this area. In the Coastal Zone of the Province of Tumbes explorations by the Government were continued on the National Reserve, and a test location has been selected in the Quebrada Zapotal about 10 miles from the Port of Zorritos. An order has been placed in the United States for drilling equipment. LaBrea-Parinas Estate.—Production on the LeBrea-Parinas Estate reached an all-time high in 1935 of 14,756,914 bbl., an increase of 636,812 bbl. over the 1934 record. The total production from 1890 to 1935 was 148,541,523 bbl. During 1935 a total of 63,021 ft. was drilled in new wells and 5449 ft. in deepening existing wells; 23 wells were deepened and 29 new wells were completed, of which 27 were producers and 2 were dry holes. At the end of the year 2873 wells had been drilled on the Estate, of which 1838 were still productive. The remaining 1035 wells represent abandoned producers or dry holes. Practically all the drilling on the property has been done with cable tools, but during 1934 three strings of rotary tools were introduced. Experience with these outfits has shown that rotary equipment can

Jan 1, 1936

By Oliver B. Hopkins

Peruvian production for the year 1935 amounted to 17,064,879 bbl., a record amount for any year, bringing the cumulative production of the country up to 188 million barrels. The 1935 figure is an increase of 785,769 bbl. over the 1934 total. The property of the International Petroleum Co. contributed 636,812 bbl. of this increase, and the Lobitos property 158,625 barrels. Exploration work in the country was again active, with attention focused on three areas, the Huallaga River, Lake Titicaca and the Coastal Zone of the Province of Tumbes. It is reported that in the Huallaga River area the Selden Breck Construction Co. has completed geological and engineering studies on its Pachitea River concessions and has ordered a drilling rig. In the Lake Titicaca region further studies in the vicinity of Pusi were made by Government geologists. During the period from 1906 to 1915, the Pirin anticline in this area produced 285,936 bbl. of low-grade crude. The Government holds 120,000 hectares of reserved lands in this area. In the Coastal Zone of the Province of Tumbes explorations by the Government were continued on the National Reserve, and a test location has been selected in the Quebrada Zapotal about 10 miles from the Port of Zorritos. An order has been placed in the United States for drilling equipment. LaBrea-Parinas Estate.—Production on the LeBrea-Parinas Estate reached an all-time high in 1935 of 14,756,914 bbl., an increase of 636,812 bbl. over the 1934 record. The total production from 1890 to 1935 was 148,541,523 bbl. During 1935 a total of 63,021 ft. was drilled in new wells and 5449 ft. in deepening existing wells; 23 wells were deepened and 29 new wells were completed, of which 27 were producers and 2 were dry holes. At the end of the year 2873 wells had been drilled on the Estate, of which 1838 were still productive. The remaining 1035 wells represent abandoned producers or dry holes. Practically all the drilling on the property has been done with cable tools, but during 1934 three strings of rotary tools were introduced. Experience with these outfits has shown that rotary equipment can

Jan 1, 1936

By Charles H. Osmond

The rapid progress of basic changes in refining processes, which has characterized this division of the petroleum industry during the last 7 years, slowed up in 1926 and the industry as a whole devoted itself to the enormous task of adopting these changes to its methods of manufacturing. If for no other reason, the year of 1926 will stand out as the first year of widespread activities in placing refining on a true manufacturing basis. A brief survey of each of the important operations and the trend of the changes with their economic results indicate the importance of this period of transition. No attempt has been made to detail the numerous activities in each of the major operations and the writer would refer those seeking such information to the various trade papers and the paper on "Basic Changes in Refining Processes," by Walter Miller.&apos; Distillation.—-Distillation (excluding cracking) is the major item in refining. During the past year there has been a wide application of the improvements developed in former years. Operating costs have been reduced for fuel, labor and capital items. Practically all types of distillations are now carried on as semi-continuous or continuous operations, rather than by the old batch method. Heat-saving devices, such as heat exchangers, or improved combustion chambers, have had a marked effect on the total fuel bill of the industry. The modern pipe-still has been widely used and figures available show that approximately 10 per cent. of the older shell equipment was replaced by pipe-stills during 1926. The range of usefulness of this type of equipment has been extended successfully to the most complicated types of lubricating oil manufacture. These stills afford marked economies in fuel as well as labor costs, also many advantages in older plants where space is limited, as a single pipe-still can replace several batteries of shell stills. Capital expenditure per barrel capacity is decidedly lower and offers economy in this direction. Although there has been considerable discussion of other types of distillation equipment such as the vacuum still, there has been no appreciable increase in these installations during 1926. Cracking.—-Cracking equipment increased rapidly during 1926 as evidenced by the increase in output of cracked gasoline from an average

Jan 1, 1927