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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

By M. A. Hunter

THIS paper gives the results of an investigation of the specific resistance and temperature coefficient of the electrical resistance of nickel and its important alloy, monel metal. For most of the pure metals, the temperature coefficient of resistance is approximately 0.0004 per degree centigrade at 2.0° C. Nickel and iron, however, are exceptions. This property is important as it gives us good material for the construction of thermometers and other instruments involving electrical control. A summary of information on this subject has been published by the Bureau of Standards.1 The present experiments antedate this publication by several years and as the information obtained is not contained in it, the results of the experiments are published as additional information. ELECTRICAL PROPERTIES OF PURE NICKEL It is generally conceded that the lowest values for electrical resistance are obtained in the purest metal. In the case of nickel, the best material obtainable is electrolytic nickel, which contains approximately. 99.80 per cent. nickel, 0.15 per cent. iron, and 0.05 per cent. copper. Any cobalt that may be present is included in the nickel figure. If the electrolytic sheet has been deposited without intermission, it is possible to cut a section from the sheet and roll it into wire without melting. By this means a nickel wire may be obtained that is uncontaminated by any of the impurities always taken up by nickel during melting.

Jan 5, 1922

By W. J. Babyak, F. N. Rhines

It has long been supposed that, regardless of the mechanism by which grain boundaries increase the hardness of a ductile metal, the effect should be linearly proportional to the grain boundary area. At the present time two methods for determining grain boundary area in an isotropic aggregate are available. The first, derived by Angus and Summers,' presumes that the grain boundary area is equal to 3vn, where n is the number of grains per sq mm in a random section through the metal. This estimate is based upon the assumption that the grains are equivalent to cubes whose faces correspond with the grains as observed in the micro-section. Measurements on copper, bronze, and a brass showed that a nearly linear relation exists between 3vn and hardness. This is illustrated, for the case of brass, in Fig. 1. The second method, developed independently by Smith and Guttman2 and by Duff in, Meussner, and Rhines,3 is absolute and employs a simple linear intercept count for measuring grain boundary area. It involves no assumptions with respect to the shape and distribution of the grain boundaries. The total surface in unit volume is 2 NL , where NL is the number of intercepts between grain boundary and unit length of a test line passed randomly through the sample. In practice, NL,, the average number of grain boundaries intercepted by unit length of traverse across a prepared microsection, is ob-

Jan 1, 1961

Mother Earth has had a long life extending over two billion years, during which time she has changed from a mass of incandescent gases to her present form, exhibiting a density stratification from the extremely tenuous gases of the stratosphere to the heavy central nickeliron core. Man is now mining all the principal divisions of Mother Earth except the centrosphere. Nitrogen, oxygen, neon, and other rarer gases are being recovered from the air; magnesium, bromium, potash, borates, and other salts from lakes and seas; brines, medicinal mineral waters, and great quantities of water for domestic and industrial uses from surface and subsurface reservoirs; and, from the rocky crust, many minerals and fuels for our present industrial civilization as well as plants and animals for food and shelter. Productivity of soil is influenced both positively and negatively by man. There is some cause to bewail what may be considered a wasteful influence of men on soil. The general situation is bad in spots but not hopeless. The passing of large areas of fertile land in some areas is merely to be noted and not to be mourned. These lands could not have been used without decrease in their fertility. The productivity factor is affected by human activities. Many soils in the eastern and southern states are far richer and more productive now than they were at any previous time. Arctic soils are not productive

Jan 1, 1950

By B. Rao Pothini, Hilmar A. von Schonfeldt

One of the key elements essential to a productive and uninterrupted longwall mining operation is roof control. In several of the Island Creek Coal Company's mining sections, polyurethane has been infused 80 into strata to control severe roof failures in the face and gate entry areas. To date about 50,000 kgs (110,000 lbs) of the chemical have been consumed in a number of applications. Roof-to-floor convergence 60 and differential roof sag have been monitored to determine the need for polyurethane infusion and also to evaluate roof stability following the infusion. Stratascopic observations of the roof formed the basis 40 for confirming the need and also for estimating the required quantities of polyurethane. Both chemical infusion and roof control monitoring techniques have been applied successfully under very adverse roof 20 conditions; substantial production benefits have been realized. Operator acceptance of the system has been very good.

Jan 1, 1981

By G. S. Hume

TuRneR Valley, on the eastern edge of the foothills of Alberta, 35 miles southwest of Calgary, continues to be the major oil field in Canada. This field began production of gas and naphtha from the Mississipian (Madison) limestone in 1924, and until 1936 all wells were drilled for these products. At the end of 1938 there were 104 gas wells. In 1936 proof was found of a crude oil zone in the same horizon but lower on the west flank of the structure, which is a large fold cut off on the east side by an overthrust fault of great displacement. Since 1936 drilling has been done for the development of crude oil and at the end of 1938 there were 64 crude oil wells. On test through a 1-in. choke these flowed at the rate of 50,000 to 60,000 bbl. a day, but on production would not be expected to make this volume. The output has been prorated according to the capacity of the Prairie market. During the harvest season, when the demand for oil and oil products was at its maximum, the allowable production of Turner Valley was 28,363 bbl. per day. With the arrival of winter, this was cut to 11,500 bbl. per day but later was raised to 12,500 bbl. Production in 1937 from Turner Valley was 2,767,221 bbl., which was more than double that of the previous year. Production in 1938 was 6,691,075 bbl., which is considerably more than double that of 1937.

Jan 1, 1939

By F. A. Hill

Coal mining in the State of Washington offers many interesting problems for the mining engineer, due to the varied physical conditions occurring in different fields, and often in, the same mine. The different coal seams worked in the same mine commonly require different mining and transportation methods for economical operation. The coal measures have inclinations ranging from 5° to vertical, and in the same mine the dip of the coal may vary from 30° to 50°. In all fields, the seams are extensively faulted, folded, and sheared. The quality of the coal produced ranges from brown lignite to bituminous- coking coal, the following being typical analyses: Lignite Sub Coking Coal bituminous Moisture 23.5 14.30 0.57 Volatile hydrocarbon 31.0 33.03 23.57 Fixed carbon 37.4 41.30 65.55 Ash 8.1 11.37 10.31 100.0. 100.00 100.00 Very little of the coal contains as much as 0.75 per cent. sulphur. The brown lignites occur mostly in Lewis and Thurston Counties, and, as a rule are very cheaply mined. This coal has been successfully used in locomotives of the Oregon & Washington Railroad, after equipping them with specially designed fireboxes. The sub-bituminous coals occur in all the coal-mining counties. Their cost of production varies widely, according to the character of the formations, the pitch, and the wall conditions. This makes a fairly good steam coal, but the lump is used mostly for domestic trade, after grading into lump, nut, and pea.

Jan 4, 1918

By K. C. Lau

INTRODUCTION The design of engineering structures such as mine openings in and foundations on rock requires a knowledge of the constitutive laws governing the behaviour of discontinuous and layered rock masses. At the present time there are two main approaches for predicting the stress distributions and displacements in such engineering structures. In one method, the whole of the rock mass is discretized. The behaviour of the components of the rock mass, that is, the joints and the intact rock are modelled using analytical techniques such as the finite or boundary element methods. Typically the intact rock is modelled as a linear elastic material bounded by non-linear discontinuities. An alternative method of analysis is to describe the load-deformation properties of the jointed, layered or even reinforced rock mass in terms of smeared or equivalent homogeneous material properties. Such equivalent material properties may then be used to compute the stress distributions around openings and in foundations using standard methods of analysis such as the finite or boundary element techniques. Once the stresses have been obtained for the equivalent material, the stresses in the individual constituent layers or discontinuities may then be determined. Each approach to the problem has particular advantages. The first method is more likely to yield results which more closely represent the behaviour of the rock mass, since the behavioural responses of both the joints and intact rock are modelled. However, for many large or complicated geologic structures such an approach can become unweildy and uneconomical. In such cases, the equivalent

Jan 1, 1984

By G. S. Hume

TuRneR Valley, on the eastern edge of the foothills of Alberta, 35 miles southwest of Calgary, continues to be the major oil field in Canada. This field began production of gas and naphtha from the Mississipian (Madison) limestone in 1924, and until 1936 all wells were drilled for these products. At the end of 1938 there were 104 gas wells. In 1936 proof was found of a crude oil zone in the same horizon but lower on the west flank of the structure, which is a large fold cut off on the east side by an overthrust fault of great displacement. Since 1936 drilling has been done for the development of crude oil and at the end of 1938 there were 64 crude oil wells. On test through a 1-in. choke these flowed at the rate of 50,000 to 60,000 bbl. a day, but on production would not be expected to make this volume. The output has been prorated according to the capacity of the Prairie market. During the harvest season, when the demand for oil and oil products was at its maximum, the allowable production of Turner Valley was 28,363 bbl. per day. With the arrival of winter, this was cut to 11,500 bbl. per day but later was raised to 12,500 bbl. Production in 1937 from Turner Valley was 2,767,221 bbl., which was more than double that of the previous year. Production in 1938 was 6,691,075 bbl., which is considerably more than double that of 1937.

Jan 1, 1939

By L. C. Uren

THE resistance to flow of mixtures of gas and oil in passing up through the flow tubing of oil wells operated by gas-lift or by natural flow is a factor in oil-recovery technic that has received but little attention. Yet accurate design of a tubing installation for a particular set of conditions, where operation is by either of 'these methods, is impossible without quantitative data on the pressure loss suffered by the oil-gas mixture in its passage through the well tubing to the surface. Because of lack of such information, petroleum production technologists have been compelled to approach this problem by "cut-and-try" methods, which, doubtless in many cases, has resulted in the installation and use of tubing too large or too small for most efficient utilization of the expansive force of the gas used in lifting the oil. Impressed with the necessity for information of this character, the authors have conducted a series of tests with large-scale apparatus in the petroleum engineering laboratories of the University of California, designed to be productive of data that would afford a means of attacking the problem of flow-tubing design on a more scientific basis.

Jan 1, 1929

By John Dasher

Extrapolation is a useful technique, but it can be overdone. Seldom is it justified to study over a range of 1 to 6 and extrapolate the results to 150,000. It is especially dangerous if the extrapolation is based on a false assumption. The authors assume settlers scale-up by residence time rather than by area, admit their result (a settler depth of 7 m) is "unreasonable" and suggest longer, wider, shallower settlers might be better. Various authors have noted for a copper-LIX system a total flow basis of 2 gpm per sq ft for sizing settlers. The results of this are compared with those in the paper in [Table 7]. The authors note that flooding of their settlers was never approached. Thus the smallest unit calculated is understandably twice too big. The largest however, is 5% of the required size. I note that the figures in [Table 6] for 1/min/cm2 are based on plan area rather than cross section as titled and are wrong by l0 4. A flow of 2050 1/min/cm2 is about Mach I. It is also 10 5/3 or 46.5 times that of the little one, although the abstract says the design was based on constant flow rate per unit cross section.

Jan 1, 1977

By Werner Goldsmith, Akihiko Kumano

An experimental investigation was conducted to study the response of soft, porous rock, green shale, under dry and liquid-filled conditions to normal impact of hemispherically-tipped cylindrical steel projectiles with diameter and mass of 6.35 mm and 31 g, respectively. Disk-shaped green shale specimens with nominal thickness and diameter of 32 mm and 127 mm, respectively, were tested in the initial projectile velocity range of 18 to 42 m/s. For the liquid-filled tests, the green shale specimens were saturated with kerosene. A total of eight impact tests were conducted. Information on the extent and pattern of the damage in the rock and velocity histories of the projectiles were collected. It was found that while the penetration depth was quadratically related to the initial projectile kinetic energy for the dry case, the penetration depth for the liquid-filled case was directly proportional to the initial projectile kinetic energy. The results of the impact tests under dry and liquid-filled conditions conformed well to a linearly viscous model and a Coulomb frictional model, respectively. The major deformation processes in the dry specimens were found to be compaction and equivolumnial distortion of the material. In the liquid-filled case, however, formation of cracks and equivolumnial distortion with less material compaction were observed. Furthermore, craters were formed as a result of the crack formation in the liquid-filled specimens.

Jan 1, 1982

By John C. McDonald

CONTROLLED cold work is used between solution heat treatment and precipitation heat treatment for producing certain tempers of the commercial aluminum base alloy 2219 (designation of the Aluminum Association, U.S.A.) which contains 6.3 pet Cu as the major ingredient responsible for the age hardening. The complete composition limits for this alloy are listed in Table I. The alloy has been described in detail,' and the control of the heat treatment has also been published.2 Beneficial effects of such cold work in other alloys have also been pointed out.3'4 NO data have been published on the effects of varying amounts of cold work under fixed aging conditions. In connection with an investigation of the possibility of providing the desired cold work by explosively generated shock waves, it became desirable to investigate the effect of variable cold work, and to compare the re -sults with those obtained from explosives. The general principles of explosive hardening are well-described in the literature.' All material used was guaranteed by the supplier

Jan 1, 1968

By A. Arrott, G. S. Ansell

A model is proposed to account for the observed strengthening behazlior of ferrous martensites. me model is based upon the inheritance of carbon-rich regions by the martensite which were present in the FERROUS martensite is formed by a nucleation and shear mechanism when austenite is cooled, at a rate which is fast enough to suppress the formation of pearlite, below a critical temperature (Ms ). Although the mechanism of the transformation process appears to be well understood,1,2 the mechanism re- austenite prior to transformation. These carbon-rich regions strengthen the martensite in a manner analogous to the strengthening effect due to a finely dispersed second phase. sponsible for the observed high strengths exhibited by ferrous martensites is uncertain. In this paper, a model is proposed to account for the strengthening of ferrous martensite. MODEL The maximum solubility of carbon in austenite is 1.98 wt pct as compared with a maximum solubility of 0.025 wt pct in ferrite. Prior to transformation, the carbon in the austenite is nonuniformly dis-

Jan 1, 1963

By L. D. Hall, S. J. Rothman

DIFFUSION coefficients of RaD (PD) and RaE (Bi) in a Bi-0.255 atomic pct Pb alloy have been measured by the methods outlined in a previous paper.' The following changes were made in the experimental procedures: the bath was made up of about 400 to 500 g Bi; and no correction was made for the volume change of bismuth on melting. The data are presented in Table I and Fig. 1. A least-squares analysis of the data yielded D = (0.120 t 0.09) exp ( -9680 + 1070/RT) D- (0.0465 0.001) exp (-8100 + 466/RT). Statistical analysis of the data indicated that the activation energies are significantly different at the 50 pct level, but not at the 75 pct level, while the D values are significantly different at the 97.5 pct level, but not at the 99 pct level. The differences are thus not as clear-cut as they were for lead. However, bismuth diffuses faster than lead in high bismuth alloys as well as in lead. The high activation energies, more than twice the value calculated from viscosities, are in good agreement with the results of Grace and Derge.' No data were obtained at higher temperatures because of gas bubble formation in the capillary. Acknowledgments This work was supported by the Office of Ordinance Research under contract DA-04-200-ORD-178. The authors thank 0. P. Vieria and M. Volpe for help in the experimental work.

Jan 1, 1957

By H. R. Gardner

THE wide variation in tension and compression properties' which exist between the a,ß and ? phases of plutonium indicate that a study of the impact properties would give a greater insight into the variables affecting the mechanical properties and formability of plutonium. In tension the a phase is quite brittle with elongations less than 1 pct. The ß phase at normal test speeds is unusually ductile; elongations up to 621 pct have been obtained. However, the ß phase is quite sensitive to strain rate; elongations decrease rapidly as strain rate is increased. The y and 6 phases are less ductile than the ß phase, with the 5 phase the more ductile of the two. Neither are very sensitive to strain rate. Considering the brittle nature of a Pu in tension and compression and the strain rate sensitivity of ß -phase Pu, both unnotched Charpy specimens and standard V-notched Charpy specimens were fabricated for testing. In addition, since iron in amounts greater than 500 ppm forms a Pu-PlgFe eutectic network which inhibits microcracking in as-cast plutonium,' it was decided to prepare impact specimens with low and high iron contents. Chemical analysis and density data for the impact specimens are presented in Table I. A total of 55 impact specimens, 32 unnotched and 23 with the standard Charpy V-notch were tested at temperatures from —45' to 330°C. The test results for both unnotched and notched specimens are illustrated in Fig. 1.

Jan 1, 1962

By Andrew Button

INTRODUCTION This review deals with the controls exerted by unconformities on the stratigraphic and areal distribution of gold (and uranium) in Precambrian conglomerates. The relations described are drawn mainly from Precambrian basins in southern Africa, particularly the Witwatersrand Basin. The mining industry of South Africa started in earnest with the discovery of diamonds in 1866. Gold was first discovered in 1870, and in March of 1886, two out-of-luck prospectors stumbled across what was to become the world's greatest goldfield, in the vicinity of Johannesburg. George Harrison and George Walker sold their claims for a pittance and were heard of no more. The Witwatersrand goldfield has been in continuous operation since that time, some 150 mines having operated at one time or another. Deep mining technology developed here has allowed operations to proceed to depths approaching 13,000 feet. The Witwatersrand has produced some 55% of all the gold ever mined, and currently produces 60% of the world's supply, some 650,000 kg Au per year. To 1971, the Witwatersrand had produced some $32 billion of gold and $2 billion of uranium (when average prices were less than $35/oz. for Au and $10/lb. for U308). At present prices, the annual Witwatersrand production of close to 700,000 kg would be worth about $10 billion. Uranium was discovered in the Witwatersrand in 1923. In the $15-30/lb. bracket, the basin contains a reasonably assured plus

Jan 1, 1983

By D. A Dahlstrom

THE necessity for slime elimination from valuable mineral and coal products has become increasingly significant within the past 5 years.' , Most of the mechanized mining and present beneficiation methods have resulted in larger tonnages of extreme fines, silts, and clay, commonly called slimes, processed by the preparation plant. Economics in turn have forced the plant operator constantly to lower the bottom size of effective beneficiation, necessitating an almost complete recovery of valuable solids regardless of particle size. When these important factors are considered, the need for an efficient slime removal method for fine solids becomes self-evident. Ordinarily slimes have been classified as ranging from 75 microns, or 200 mesh, down to colloidal dimensions of less than one micron. At the same time there is general agreement that the most troublesome slimes are primarily clays, silts and extreme fines, so that the actual top size may be placed at approximately 30 to 40 microns. This immediately restricts any desliming operation to classification, as screening or other methods would be both uneconomical and grossly inefficient at such dimensions. The liquid-solid cyclone has been recognized as one of the most efficient fine size classifiers available to the mining industry. Applications of cyclones to thickening, high efficiency solid recovery, degritting,

Jan 1, 1953

By O. N. Carlson, K. E. Solie

The brittle-ductile transition temperatures of single and poly crystalline chromium metal were studied as a function of nitrogen concentration and chromium nitride distribution. It was observed that In recent years there has been an increasing interest in chromium-base alloys for high-temperature applications. The principal disadvantages, however, have been the difficulties of fabrication and the design problems associated with a material of such limited ductility. Various studies have been the effects noted in the poly crystalline material are essentially reversed in the single crystals. These observations are discussed in terms of existing theories for the brittleness of chromium. conducted recently directed toward a determination of the cause of this brittleness and to find ways for minimizing its effects. Allen et al.,' Wain Abrahamson and rant,' and weaver4 have carried out studies on the effects of interstitial impurities on the brittle-ductile transition of chromium metal of various degrees of purity. These investigations have shown that oxygen has little or no effect on the transition temperature of chromium in all conditions studied but that carbon increases the transition temperature under all conditions tested. Nitrogen was found to increase the transition temperature in the wrought condition and in the quenched or cast conditionS but reportedly has no effect in the furnace-cooled condition.

Jan 1, 1964

By A. Donald Kelmers, Forest G. Seeley, B. Zane Egan

INTRODUCTION Coal ash, presently the fifth most abundant of the solid minerals produced in the United States, is expected to become the fourth most abundant by the end of this decade (1). The production of fly ash from the combustion of pulverized coal amounted to a total of 44 million metric tons (Mt) in 1977 and is expected to Increase to 91 Mt by 1985. Coal ash, which results from the Inorganic clay and mineral content of the coal, contains several elements and thus can be considered as a mined and crushed mineral resource rather than a waste material Furthermore, potential problems associated with fly-ash disposal ponds and the leaching of potentially hazardous elements through groundwater infiltration and/or rainfall provide additional incentive for processing fly ash for environ- mental control as well as for the recovery of certain metal values. Fly ash could provide an abundant domestic source of aluminum and several other metals Aluminum is now recovered from bauxite, and over 90% of this ore is imported since domestic sources are limited and cannot meet the U.S. demand There is a close relationship between the aluminum content of fly ash and the domestic consumption of this metal (Table 1).

Jan 1, 1981