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By Gustaf Ising

For relative gravity measurements, the author in 1918 described an instrument1 of which the essential part consists of a highly astatized, standing pendulum turning about a horizontal elastic axis. This type of instrument has been used recently in practical field work, therefore a description of its principle and technical development is given herein. Part I, describing the principle, is a direct translation of the original Swedish paper.1 Part II gives an account of the practical elaboration of the instrument, together with some description of measure-ments performed.

Jan 1, 1937

By Ralph Arnold

The lure of possible new oil fields shut off development of the older Montana fields during the year 1928, cutting down the total production to less than the 1927 mark. However, with the production of oil worth approximately $7,000,000 during the past 12 months, Montana oil producers pushed their total up to $44,000,000 taken from two principal fields during the past 8 years. The highest prices in the United States for oil of similar gravity gave northern Montana producers a decided advantage and brought up the value of the oil to about the same value as the 1927 production, although the oil runs were 1,000,000 bbl. less. Production by Fields The discovery of two new oil fields in the Sweetgrass Arch, in north central Montana, in 1927, diverted attention from the Kevin-Sunburst field. Many operators turned their attention to wildcats and practically all of the drilling contractors were called into the new Pondera and Bannatyne fields. Although discovered in 1927, the Pondera field developed its first commercial production in March of 1928. Mild interest was followed four months later by a rush of operators, and by August practically every string of tools had been moved from the Kevin-Sunburst field to Pondera. The fall months found 40 wells drilling in this field and as the year closed there were 100 producers. Pondera field is remarkable in that every well thus far drilled within the structure proper has been a producer. Dry holes have been drilled around the field, but none within an area of four sections. Experts estimate that Pondera will produce 5000 bbl, of oil to the acre. The producing area now outlined by wells drilled is expected to produce around 15,000,000 bbl. of oil. Pondera crude brings $1.75. This field has one pipe line and a second line is being laid. Lack of a pipe line delayed development of the new Bannatyne field, south of Pondera, and also in the Sweetgrass Arch. Bannatyne has 11 producing wells scattered over an area of approximately three sections. Bannatyne is a sand field with a 70-ft. sand in the lower Jurassic, which core-drill tests show to be 60 per cent. saturated. With the completion

Jan 1, 1929

By D. T. MacRoberts

This paper embodies the results of theoretical studies concerning gas reservoirs, especially the effect of drilling programs of various intensities upon pressure depletion and ultimate recoveries. The primary objective has been to determine the net quantity of recoverable gas that could be obtained as a result of each additional well, in comparison with the gas . that might be secured from a single well ideally placed with respect to both acreage and geological structure. No method is yet known whereby the relative merits of intensive and sparse drilling can be compared experimentally; a reservoir must either be drilled closely or developed with wide spacing, but both programs cannot be conducted simultaneously. Hence, the analytical method seems to be the only approach to the problem. While the present state of our theoretical knowledge does not offer a precise solution to the problem of gas flow in sand bodies, it takes such appropriate cognizance of the limitations of the methods used as to restrict any answer obtained to the realm of engineering accuracy. In solving the problem for the average gas field, it was found that practically the same answers resulted as to pressure distribution, regardless of the size of the drainage radius, even though the latter was assumed to vary from a few feet as a minimum to that of the entire reservoir as a maximum. Such limits represent extreme possibilities; therefore, the practical conditions that are associated with normal development programs, in which wells are placed in the center of tracts varying in size from 40 to 640 acres, will of necessity result in less extreme variations than those indicated in the tables accompanying this paper. Stated more concisely, the amount of gas unrecovered at abandonment (of the particular field used for illustrative purposes) will lie somewhere between 4.6 and 6 per cent of the total original content, no matter how intensively the field is drilled. Gas reservoirs may be divided into two general types, those in which the energy is intrinsic, and those of which the energy is extrinsic. † The first type contains energy in the form of a compressed gas, which expands

Jan 1, 1938

US 4,190,434 - In the thermal production of magnesium metal, a mixture of calcined dolomite, an iron- silicon-aluminum alloy as a reductant, and residual slag from the production of ferrochromium is smelted to evolve magnesium vapor, which is then condensed. The use of bauxite is lessened or eliminated because of the relatively high alumina content of the residual slag. R. Bonfils, A. Mena, C. Payn, and L. Septier, assigned to Ste. Francaise d’Electrometallurgie (SOFREM). Feb. 26, 1980. 6 pp. (75-10R). Filed: 6-14-78 (915,387). Priority: France, 6-24-77 (77/20,227).

Jan 1, 1982

By A. Kavetsky, W. J. Whiten

Data from ball mills with a wide range of diameters are analyzed using detailed mathematical/ numerical models. Analysis shows the relative power inefficiency of large ball mills is due to their inefficient breakage of coarse particles. The models developed can be used to scale-up mill behavior. The behavior of large mills at Bougainville and Pinto Valley is compared. It is concluded that the mills are equally inefficient at grinding coarse particles. Differences in coarseness of total mill feed are shown to account for the fact that Pinto Valley mills achieved design throughput whereas Bougainville mills did not.

Jan 1, 1985

By J. L. Weeks, K. F. Smith

IN order to determine the magnitude of thermal conductivity changes resulting from alloying vanadium with titanium and a few other elements, several sam~les were PrePared and measured. The thermal conductivity -values reported herein in Table I were determined with an apparatus previously described.' As in recently reported2 determinations on uranium and uranium alloys, whose thermal conductivities are in the same range as vanadium," the accuracy of the values was checked by using synthetic sapphire." The error in the measurement is estimated to be '-3 pct or 0.003 cal sec-1 cm-l "C-1, whichever is larger. The vanadium used in preparing the samples was the calcium-reduced type and was supplied by the Electro Metallurgical Co. as 99.6+ pct pure. All alloying elements used in the preparations were 99+ pct pure. A nonconsumable tungsten electrode arc furnace was used for melting the alloys and, without opening the furnace, each ingot was re-melted a number of times to insure homogeneity. The samples as prepared by the Armour Research Foundation were machined from as forged material without annealing. Acknowledgment The note is based on work performed under the auspices of the AEC. References 'J. L. Weeks and R. L. Seifert: Apparatus for the Measurement of the Thermal Conductivity of Solids. Review of Scientific Instruments (1953) 24, pp. 1054-1057. 2 J. L. Weeks: Thermal Conductivity of Uranium and Several Uranium Alloys. Trans. AIME (1955) 203, p. 192; Journal of Metals (January 1955). 3C. A. Hampel: Rare Metals Handbook. (1954) p. 593. New York. Reinhold Publishing Corp. Thermal conductivity of vanadium is given as 0.074 cal sec-1 cm- '°C-1 at 100°C. 4 J. L. Weeks and R. L. Seifert: Note Regarding the Thermal Conductivity of Synthetic Sapphire. Journal Amer. Ceramic Soc. (1952) 35, p. 15. At 70°C, K = 0.071 cal sec-l cm-l °C-1.

Jan 1, 1956

The income of the Institute is derived from dues, subscriptions to MINING AND METALLURGY and sale of publications. These sources are fortunately supplemented by the interest from invested funds now amounting to over $500,000, a considerable portion constituting endowments for especial purposes. Aside from the medal funds the principal endowments are the James Douglas Fund for support of the Library, the Rocky Mountain Fund and the Seeley W. Mudd M.emoria1 Fund. The income from the two last named is available for the support of research and a variety of other purposes. It is allocated by the Board of Directors upon recommendation of standing committees in each case. An active effort is being made to increase the endowments of the Institute, it being felt that unusual opportunities exist for research and public and professional service through the organization and at a minimum of expense.

Jan 1, 1932

The income of the Institute is derived from dues, subscriptions to MINING AND METALLURGY and sale of publications. These sources are fortunately supplemented by the interest from invested funds now amounting to over $500,000, a considerable portion constituting endowments for especial purposes. Aside from the medal funds the principal endowments are the James Douglas Fund for support of the Library, the Rocky Mountain Fund and the Seeley W. Mudd Memorial Fund. The income from the two last named is available for the support of research and a variety of other purposes. It is allocated by the Board of Directors upon recommendation of standing committees in each case. An active effort is being made to increase the endowments of the Institute, it being felt that unusual opportunities exist for research and public and professional service through the organization and at a minimum of expense.

Jan 1, 1932

By David J. Mack

A survey and critical appraisal of published information about Young's modulus was originally made by the writer because of a complete lack of information about this very important quantity in works on. mechanics, physical metallurgy, physics, and other sciences. It was felt that a comprehensive summary of such information about Young's modulus might be of general interest and may suggest new problems or lines of attack on other problems that involve E. Hence this paper has been prepared even though it is only a review, with no new ideas or experimental data. The references are only those used in assembling the paper. No attempt was made to compile a complete bibliography on the subject of Young's modulus. CalculatioX oP YouNg's Modulus from Theoretical or Empirical CoNsidera-tions Many attempts have been made to compute E from theoretical considerations. The earliest calculations were probably those of Tomlenson (1883) and Souther-land (1891), but Fess'enden4',~ made extensive calculations a few years later and arrived at the relationship: £ = 78.TOw(i)* where V is the atomic volume. In 1923, Peczalski, working from the same standpoint but with more information available on atomic structure, arrived at an identical relationship, which he expressed as: where B is a constant of value about 8 . 107, p is density and mis atomic weight; the atomic volume, of course, being ml p. Portevind4 immediately pointcd out that while the equations of Fessenden and Peczalski were true of the common metals, they gave low values for the refractory metals with high moduli (Fig. I). He showed (Fig. 2) that much better concordance was obtained by means of an empirical equation of the form: F- KT" where K is a constant; T the absolute melting point; V, atomic volume, and a and b constants of value approximately I and 2 respectively. This constant K in the Portevin equation is not necessarily the same for all elements, as shown by Thompson. Other equations for E based upon theoretical considerations have been derived by Honda and Yamada49 and Lasareff.50 The most recent calculations of elastic moduli based upon quantum mechanics are probably those of Fuchs He extended the method of Wigner and Seitz for calculating the lattice energy and compressibility of monovalent metals and computed the elastic constants of lithium, 18

Jan 1, 1946

ELECTROREFINING Canadian 1,023,691 -Removal of bismuth from slime filtrate in the Betts process refining of lead. The filtrate is subjected to electrolysis in a cell having an anode of crude lead and a cathode of refined lead under operating conditions to preferentially deposit bismuth on the cathode. The substantially bismuth-free filtrate is recycled for use in the process as the electrolyte for producing high-purity lead. S. Hirakawa and R. Oniwa, assigned to Mitsui Mining & Smelting Co., Ltd. Jan. 3, 1978. 8 pp. (204-73). Filed: 2-18-74 (192,810). Same: U.S. 4,026,776, dated May 31, 1977.

Jan 1, 1979

By R. V. Ramani, G. W. Luxbacher

Computer simulation of mine ventilation system is rapidly becoming an essential tool in mine planning and design. This Paper examines the utilization of ventilation simulation techniques to evaluate the number, shape, size and layout of mine entries in a typical coal mining system. Since the mains and sub-mains serve primarily for transportation and ventilation and the ventilation system is critically important to the health and safety of the workers, there exists a great need for optimal designs in this area. Evaluation criteria could include, among others, minimization of power costs, shaft requirements and leakage. Constraints of this optimization problem include health and safety regulations and production and mine infrastructure requirements.

Jan 1, 1980

By K. D. Hester, A. C. Anderson

The Elliot Lake uranium deposits are contained in a pebble conglomerate which is similar throughout the basin. This paper compares the solid-liquid separation circuits of two nominal 3000 T/d acid leach uranium concentrates treating Elliot Lake ore. One concentrator employed rotary vacuum drum filtration for solids removal and washing, the .other used counter current decantation in torque arm thickeners. Capital and operating costs, operation and maintenance, and metallurgical performance of the two solution recovery methods are compared and contrasted. A recent development, removal of the sand fraction ahead of C.C.D. and separate sand washing in hydraulic cyclones, is also discussed.

Jan 1, 1973

By George H. West, Ross Cummings, L. V. Steck, B. P. Little, Robert D. Pike

The drilling of constantly deeper oil wells has made it imperative that the manufacturer of casing be ever searching for new methods and new materials to meet the increased demands. One phase of this search constitutes the subject matter of the present paper. Starting from the original Drake well in 1859, the depth of wells has advanced by leaps and bounds, until today depths of 6000 to 8000 ft. are common. Conditions point to the necessity for drilling to greater depths, and it is not at all improbable that much of the future oil produc- tion will be from wells around 10,000 ft. deep. The trend to deeper wells is nicely illustrated by the curve in Fig. 1.l The points plotted are the maximum depths attained in the various pools which were at their peak for the years given. It may be of some interest to observe the change that has taken place in the tensile and collapsing stresses over the last 25 years. The pressure at the bottom of a 900-ft. hole, equivalent to the pressure caused by an equal column of water, is only 450 1b. per sq. in. The equivalent water pressure corresponding to the depth of the deepest hole today would be 4762 1b. per sq, inch.

Jan 1, 1930

By W. I. Duvall, L. D. Sadwin

Three explosives with different detonation characteristics were tested by studying their cratering ability in a granite-gneiss. The strain wave generating characteristics of these explosives were also studied in the same rock medium. Correlations between the relative performance of three explosives as evaluated by crater studies and other methods of evaluation are indicated. Numerous test methods have been employed to evaluate the output performance of explosives; for example, the underwater explosion method, the airblast method and the ballistic pendulum method.'*' For blasting applications, the study of explosion produced craters and explosion generated strain waves are the most meaningful. This laboratory has employed these techniques extensively for many years and has shown that the detonation properties of explosives and their ability to generate strain waves in rock are related and that the amplitude and shape of the strain wave is related to some of the crater parameters such as slab thickness and fly rock velocity.3'11 However, a good comparison between the relative performance of explosives as determined by the crater and strain wave methods had not been made. The purpose of this investigation was to determine if the relative performance of three explosives as determined by the crater method shows a correlation with the relative performance as determined by the strain wave method. If a good correlation exists between these two sets of relative performance, it should then be possible to relate the detonation properties of an explosive to its ability to break rock in a crater test. In most commercial blasting operations, the diameter of the blast hole remains constant even though the type of explosive may change. In general, it is the explosive volume rather than the weight which remains constant when two or more explosives of different density are compared. Therefore all tests in this investigation were conducted on a constant volume basis rather than on a constant weight basis. TEST SITE AND ROCK PROPERTIES The tests described in this paper were conducted at a granite quarry owned and operated by the Consolidated Quarries Div. of the Georgia Marble Co. at Lithonia, Ga. The tests were performed in an area where the exposed rock surface was nearly horizontal and where the general rock mass had few joints or faults. The rock has an apparent sp gr of 2.6 and a longitudinal propagation velocity of 18,000 fps. The characteristic impedance of Lithonia granite gneiss is 53(lb - sec/in3). EXPERIMENTAL PROCEDURE There are many parameters which must be considered in the study of explosion-produced craters. The role played by each variable in the explosive-rock-crater system can be determined by experimental techniques in which one parameter is varied while others are maintained constant. In this investigation, the crater geometry was studied as the depth was varied for each of three explosives. The explosive volume and rock-type were held constant for all crater tests. The experimental arrangement used in performing the crater tests is illustrated schematically in Fig. 1.

Jan 1, 1965

By F. Julius Fohs

WITH portions of two coal basins within its borders and a few scattered fields already developed, the question arises: What is the future of Ken-tucky as an oil-producing State? Is the long list of failures due to lack of 'commercial pools, or unintelligent prospecting? A study of its beds and irregularities of structure points not only to a large waste of development money on unpromising areas, but also to the presence of a few structures well worthy of development. The surface rocks of Kentucky show in succession more than 4,000 ft. of Paleozoic sediments and more than 2,000 ft. of Cretaceous, Tertiary, and more recent deposits. Folding and erosion have brought these beds to the surface, where they have been observed and studied: in detail by my associate, James H. Gardner, myself, and others. This has given opportunity to observe the beds offering suitable reservoirs and having the proper impermeable covering; also the mapping of outcrops and outcrop lines, taken in conjunction with available well records, indicates that certain areas are worth testing, and with even greater definiteness shows areas which should be excluded, as devoid of possibilities. West of the Tennessee River, Cretaceous, Tertiary, and Quaternary sediments occur so that all trace of ancient folding is obliterated, the sediments overlapping unconformably Mississippian rocks. This area embraces 2,000 square miles, or one-twentieth of the area of the State, the Paleozoic rocks covering the remainder. Since there is nothing upon which to base the location of tests for oil and gas in the Cretaceous-Tertiary beds of Kentucky, the Paleozoic area will be chiefly considered.

Jan 3, 1915

By Y. C. Liu

The orientation relationship between the dejormation and recrystallization textztres of binary Cu-P alloys of high phosphorus content was observed to he a ± 14-deg (110) rotation. According to the ori-ented-gvowth hypothesis, the same relationship should exist between a successfully flowing pain and the strained single-crystal matrix of alloys of corresponding composition. The orientations of thirty successfully growing grains were obtained in a Cu-1.0 at. pct P alloy. Both a conventional analysis and the more detailed analysis advanced in the present study demonstrate that the observed orientation relationship is not comparahle to that predicted by the oriented growth hypothesis. IT has been shown experimentally that the formation of recrystallization textures in metals may be explained on the basis of the oriented-growth hypothesis. This conclusion is based primarily on the results of cooperative experiments carried out by various investigators in aluminum. Beck and HU' suggested that the orientation relationship between the recrystallization and deformation textures of aluminum is a 38-deg(111) rotation. A similar relationship, i.e., a 40-deg(111) rotation, was observed between the primary and secondary recrys-tallization textures.' Since the secondary grains result from a process of selective growth, this naturally implies that the same mechanism is also responsible for the formation of the primary re-crystallization texture from the deformed matrix. Further evidence was provided by the experiments of Liebmann, Liicke, and Massing3 and Yoshida, Liebmann, and Lucke.4 They observed that grains which could successfully grow into strained aluminum single crystals invariably exhibited the same orientation relationships with their matrix. Thus, regardless of other opinions,5'9 these results offered good evidence in favor of the oriented-growth hypothesis. In order to examine broader applications of this oriented-growth hypothesis, experiments should be carried out in metals other than aluminum. In a recent investigation on the recrystallization textures of binary copper alloys with phosphorus, arsenic, and antimony,7 it was found that the predominant recrystallization components were related to the deformation textures by a (110) rotation. The (110) rotational relationship is different from the (111) relationship generally proposed between the recrystallization and deformation components of other binary copper alloys. 1,8,9 Applying the observations made for aluminum, the oriented-growth hypothesis predicts that the orientation relationship of grains successfully growing into the strained single crystals of either one of these copper alloys should correspond to that observed in the textural study. Verification of this prediction would provide a critical test of general applicability of the oriented-growth hypothesis to the formation of recrystallization textures in fcc metals other than aluminum. The Cu-1.0 at. pct P alloy was selected in the

Jan 1, 1964

By C. N. J. Wagner, E. N. Aqua

The bee alloys of the terminal solid solution of rhenium in niobium were investigated by X-ray diffraclion methods. The analysis of the broadening of the powder pattern peaks from the niobium-rich alloys, cold-worked by filing, showed evidence for faulting on (211) planes. The alloys with larger rhenium concentrations were brittle, and fractured when filed. The analysis of the shapes of the diffraction profiles from powders produced by hammering with steel plates) of these brittle alloys indicated that the broadening was due predominantly to platelets bounded by clibe planes. This result was consistent with the Laue patterns from single-cleazlage facets which showed evidence for clearage fracture on {100} planes. The influence of faulting on the mechanical properties of face-centered cubic (fcc) metals and alloys, i.e., how faulting affects the various dislocation configurations in fcc metals, is well-known.' The important question is whether or not faulting occurs in body-centered cubic (bcc) metals and alloys, and, furthermore, if faulting does occur, to what extent it affects the mechanical properties. Theoretical calculations indicate that the stacking-fault energy is rather high in most bcc metals.2 The results of sev-eral studies using transmission electron microscopy have indicated that faults are present in well-annealed and lightly deformed bcc metals and alloys, such as tungsten,3 vanadium,4 and Mo-Re alloys.5,6 These faults, as have been observed, may be stabilized by the presence of interstitial (C,N,O) atom segregation to the extended dislocations. In addition, there is considerable X-ray diffraction evidence for faulting in bee metals,7-8 using the same techniques that were successful for the study of faulting in fee metals and alloys.7 This X-ray diffraction method is currently the only technique applicable for the investigation of faulting in metals with high stacking fault energies, i.e., when severe amounts of deformation are required to produce sufficient amounts of faulting to be detectable by X-rays. The thinned films of heavily deformed metals will become opaque in the electron microscope due to the high dislocation densities present. In a previous investigation of faulting8 in bee metals of group Vb and VIb, the authors observed that niobium was ductile when filed at room temperature, and showed the highest density of faults on the (112) family of planes. A niobium-base alloy system was therefore chosen to study the effect of alloying on the occurrence of faults in a bcc alloy. There is a large range of terminal solid solubility of rhenium in the alloys of the bee refractory metals. All of the Group VIb-rhenium alloys, i.e., Cr-Re, Mo-Re, and W-Re, exhibit solid solution hardening without loss of ductility.9 In fact, the ductility reaches a maximum for alloys with compositions near to the limits of solubility. This enhanced ductility has been attributed to the lowering of the stacking-fault energy in the alloy; i.e., the increased amounts of twinning provide an additional mode of deformation, resulting in the observed high ductility.' Because of this demonstrated effect of rhenium in bee alloys, it was decided to study a series of alloys of Nb-Re. Using the same X-ray diffraction methods as described in the previous investigation,' one is able to identify the possible causes of broadening of the powder pattern peaks, e.q., particle size, microstrains, stacking faults, and/or twin faults. The separation of these various contributions to the measured peak shape is accomplished by the Warren-Averbach analysis.7 I) EXPERIMENTAL PROCEDURE A series of seven bee solid solution alloys containing from 2.5 to 21.5 at. pct Re (remainder niobium) were prepared at the General Electric Research Laboratory. Buttons, weighing 25 g, were alloyed from electron-beam-melted niobium chips and random rhenium sheet by arc melting in a water-cooled copper crucible, under an argon atmosphere. The buttons were inverted and completely remelted to promote homogenization. The nominal alloy compositions are listed in Table I. Samples of the cold-worked alloys were obtained by filing to produce a powder for the X-ray study. Alloys too brittle to be filed were hammered with steel plates. The resultant filings or brittle impactings were screened through 150-mesh classifiers and compacted to the required shape for the diffractometer holder. The X-ray diffraction peaks were automatically recorded by fixed time counting at uniform 28 intervals, or by continuous registration with a ratemeter. In all cases, the (110)-(220) and (200)-(400) pairs of peaks and the (211), (310), (222), and (321) reflections were measured on a GE-XRD5 diffractometer using CuKa radiation with nickel filter or MoKct radiation and a LiF monochromator in the diffracted beam. The first part of the data reduction, completed with the aid of a series of programmed computations,10 was the analytical resolution of the Kol component of the diffraction profile. Subsequent computations were then made with reference only to the resolved Kol peak shape. These included the measurement of the

Jan 1, 1967

By Marshall B. Standing, Donald L. Katz

DENSITY data are reported on 16 saturated hydrocarbon vapors at pressures ranging from 1000 to 8220 lb. per sq. in. and at temperatures ranging from 35° to 250°F. These data have been used to extend the compressibility-factor chart for natural gases up to 10,000 lb. per sq. in. The relatively large quantity of high-boiling constituents present in high-pressure vapors in equilibrium with crude oils makes it necessary to include in the analysis of the gas the molecular weight, density, and possibly boiling range of the heptanes and heavier fraction. Relationships have been presented by which the density of gases may be obtained directly from the temperature, pressure, and gas gravity provided the gases have a common source or are similar in composition. INTRODUCTION The densities of natural gases are necessary in many engineering computations in petroleum production and utilization. Gas reserves, changes in reservoir pressure, gradients in gas wells, metering of gases, pipeline flow, and compression of gases are typical problems requiring the density of the gas. A decade ago, engineering computations used ideal gas laws with deviations up to 500 lb. per sq. in.4 Recent discoveries of pools having pressures up to 7500 lb. per sq. in., and installation of pressure-maintenance and recycling plants, have increased the need for data on gas density at high pressures. METHODS OF COMPUTATION The accepted method of computing the density or specific volume of natural gases is the use of the ideal gas law corrected by a compressibility factor. The method proposed by Kay7 of correlating compressibility factors for gaseous mixtures on pseudocritical properties5 appears to be satisfactory for natural gases.2 The methane-compressibility factor has been shown to deviate systematically from the behavior of natural gases2 and a chart giving these corrected factors is available. A method of computing specific volume of gaseous mixtures from partial molal volumes has been reported by Sage and Lacey.8 Complete data for the computation are not yet available for all hydrocarbon gases. Most of the reported data on gas densities have been in the single-phase region removed from the dew point or saturation condition. Since most gases in the reservoir or while on contact with liquid during flow are saturated, the determination of densities under conditions of saturation is particularly important. Although there is no reason to believe that the saturated gases differ in behavior from those considerably removed from their dew points, the usual experimental determinations find difficulty on approaching the dew-point conditions. This paper reports the density of 16 saturated gases in equilibrium with crude oils. The relationships developed to compute the density of gases to high pressure' have been modified and enlarged. A simplified method of obtaining gas density is presented in the form of charts, which apply for specific groups of gases.

Jan 1, 1941

By John B. Mertie

More than 200 minerals are known that contain the rare-earths and thorium. Monazite and bastnaesite, however, are the principal commercial sources of the rare-earths, and monazite is the principal source of thorium. Monazite was in demand in earlier years mainly for its content of thorium, which was used in the manufacture of Welsbach gas mantles; but beginning in the latter part of the nineteenth century, the rare-earths became progressively more important than thorium. Recently, however, the tenor of thorium in monazite has again become a matter of commercial interest. Rare-Earths and Thorium The rare-earths proper are defined by spectroscopists as the oxides of 14 elements with atomic numbers ranging from 58 to 71; but more commonly lanthanum, with an atomic number of 57, is also included, in which case these 15 elements are often designated as the lanthanides. Chemists also include scandium and yttrium as elements of the rare-earths. A second group of elements, beginning with actinium and including thorium, protactinium, uranium, and all the transuranium elements so far produced, with atomic numbers ranging from 89 upward, are chemically and structurally related to the lanthanides, and are known as the higher rare-earths or actinides. Berzelius discovered that the lanthanides could be separated roughly into three groups, based upon the solubility of their double salts, R2(SO4)3-K2SO4-2H2O, in excess of K2SO4. This separation, with the substitution of sodium for potassium, is still used commercially. The double salts of the cerium earths were found to be almost insoluble; the terbium earths, partly soluble; and the yttrium earths, completely soluble. Based upon the degree of solubility, scandium belongs with the cerium earths; and yttrium belongs with, and gives its name to, the yttrium earths. These three groups with their atomic numbers are shown below. [ ] The prevailing state of oxidation for the rare-earths is R2O3, but cerium may readily be oxidized to the tetravalent state, in which condition it may be separated chemically from the other cerium earths. Praseodymium and terbium may also exist with the valence IV, and samarium, europium, and ytterbium may have the valence II. Most of the elements of the rare-earths, however, are very difficult to separate, and their initial isolation required the work of many chemists over a period of 150 years.20 Fractional crystallization, fractional precipitation, and ion exchange are the principal methods so far used, and fractional precipitation is now employed commercially on a large scale. Ion exchange columns are

Jan 1, 1960

By Richard H. Willey

EFFICIENT handling of large tonnages in open-pit mining demands, primarily, an abundance of well fragmented rock. To accomplish this, a drilling and blasting department composed of a well-knit, versatile group of workers and supervisors must be established. Some costs will remain relatively on the same level over a period of years, while others can be greatly lowered as will be shown. The Utah Copper Division, Kennecott Copper Corp., Bingham Canyon, Utah, has been ever alert for improvements in operating methods and equipment to gain increased efficiency and lower costs. BINGHAM CANYON MINE The greatest dimension of the mine is 8000 ft northeast-southwest with a width of 5000 ft southeast-northwest. From the lowest level, at an elevation of 6040 ft above sea-level, the mountain rises in 27 benches on the west side to W level (elevation 7800 ft) and 21 benches on the east side to Q level (elevation 7460 ft). At the inception of open-pit mining in 1906, the overcapping of leached porphyry had to be removed to reach a commercial grade of sulphide ore. The overcapping or waste now remaining is quartzite with intercalated limestone beds. The limestones are usually soft in nature except in the south-middle portion of the mine where they have been metamorphized along the contact zone. This area usually gives drilling and blasting operations a great deal of trouble. Here occurs the greatest amount of secondary blasting, as the well-established fracture planes cause the altered beds to break into large boulders. Several massive quartzite "ribs" occur in the overburden, and as a result, the uniform breakage is difficult to obtain. The major quartzite areas have been subjected to complex folding, fracturing and faulting because of the intrusion of the underlying stock. The monzonite porphyry, which carries the commercial values, presents no serious drilling problem because of its softness and extensive minute fracturing throughout the mass. A series of major slips or faults pass through the ore body which, although of considerable advantage to the drilling and blasting department, sometimes works to the disadvantage of the track department. Drilling and blasting of the porphyry apparently becomes easier as depth is attained, but highly siliceous streaks throughout the pit still present difficulties. At no place is the rock of such character as to allow excavation without preparations. On certain higher elevations or levels, old fill material can be dug by the shovels, but only at some risk to equipment because of bank slippage. PAST METHODS At the outset of shovel operations in 1906, drilling was done with the Ingersoll-Rand F-24 piston drill mounted on an un-

Jan 1, 1947