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By B. H. Caudle, A. B. Dyes

In a recent publication' it was shown that wells with a free surface in a homogeneous gravity-drainage reservoir have a hyperbolic decline with index n '. This paper reports efforts to extend this theory to practical field cases. As a first step in making the extension, a large number of lease production curves from gravity-drainage fields in the stripper stage were fitted with the general hyperbolic decline equation, q/q, = 1/(1 + y) y and n in each case being determined by statistical methods. It was found that this equation is reliable for decline curve extrapolation for periods up to at least 25 years. The resrilts obtained were disturbing in the sense that values for the index, n, were often smaller than one, which fact leads to the prediction that a well would produce all infinite amount of oil in infinite time. A theoretical investigation based on the results of the previous paper provides a suitable explanation for these low values of n. It suggests that these are obtained if production occurs from two or more layers of diflerent permeabilitv and thicktress or two lnyers having different skin effects. It is predicted that as the more permeable layers are exhausted, the index of decline, n, will rise from a value smaller than 2, to n = 2. A practical method is given for fitting the general hyperbolic decline Eq. 6 to production decline data. When this method is used, the index of decline observed in gravity-drainage reservoirs in the stripper stage when wing only data over early years 01 decline usually agrees quite closely with that determined using data over 25 years or more. This indicates that the hyperbolic decline equation is reliable for predicting behavior of such reservoirs. A method is also suggested for taking into account any changes in the value of the index INTRODUCTION As a result of both experimental work with models and theoretical deductions, it was recently concluded' that wells having a free surface in a homogeneous reservoir producing by pure gravity drainage should have a hyperbolic decline with n = 2. The present report details efforts to extend this work on ideal homogeneous reservoirs to actual field cases. It should be remembered that both the previous work and the present extension are based on the assumption that the reservoir is at very low pressure, and hence, nearly all the potential available for driving fluid to the well is the gravity head. Attempts to apply conclusions of this study to reservoirs which have considerable pressures supplementing the gravity drive may lead to difficulty. WELLS WITH NO FREE SURFACE In a dipping gravity-drainage reservoir such as that shown in Fig. 1, some of the down-dip wells have no free surface. The previous study' showed that the up-dip wells, which have a free surface, should follow Eq. 1. The following approximate analysis, of a type which was justified experimentally for up-dip wells in the work just mentioned, leads to results for the down-dip wells.

One of the most unusual assignments in the his¬tory of Loffland Bros. Co. is now in progress with the drilling of a 72-in. diam. shaft in Nevada for the United States Atomic Energy Commission. Projected depth being 3200 ft, by volume, this is the same as a 216,672-ft hole 83/4 in. in diam. Every aspect of the operation is king-sized. The 15,000-lb bit moves into position over the well on a specially-made railroad car riding on rails 14 ft apart. The single drill collar weighs 300,000 lb, is 60 in. in diam., and 43 ft long. The drill pipe is 133/s-in. 72-in. N-80 casing fabricated with special tool joints. The bit chews up 1.05 cu yd of rock for every ft of penetration (This is equal to the volume of 67.71 ft of 83/4-in. hole.

Jan 9, 1964

By J. R. Ross, J. B. Rosenbaum

Bureau of Mines research has resulted in the development of fluid- bed ion-exchange columns for recovering uranium from slime pulps. In pilot plant tests, slime slurries containing up to 6 percent solids were processed at flow rates of 10 gallons per square foot per minute with high uranium recoveries and efficient resin loadings. Uranium was effectively eluted in a laboratory fluid-bed elution column at eluate-to-resin ratios of less than 5:1 and eluate flow rates of 3 gallons per square foot per minute. Construction costs of mills using these improved ion exchange techniques are estimated to be 25 percent less than for mills using solvent extraction of clear solutions. For mills having a capacity of 2,000 to 2,500 tons of ore per day, the saving would be in the range of $2.5 million. In addition, a saving of about $0.80 per ton of ore in total operating costs is indicated.

Jan 1, 1973

By C. H. Noren

For some years the Du Pont Company has utilized computer calculations to study the various theoretical properties of explosives. These studies have yielded valuable information on the effects of density changes or formulation changes on detonation rate, detonation pressure, explosion pressure, heat of explosion and numerous other properties, and have aided in evaluating the theoretical potential of explosives. In addition, a multitude of laboratory tests have been utilized for the evaluation of explosives. When comparing the computer data and the voluminous test data it became evident that numerous anomalies existed. Tests in rock were required to study explosives under borehole confinement. This fact was further emphasized after numerous field measurements showed that the borehole velocity of commercial explosives did not match the theoretical value but was dependent on conditions of field use. Since we are interested in the practical aspects of blasting, a program was initiated to evaluate explosives as used in commercial blasting. INSTRUMENTATION Most of you are familiar with the extensive work that has been done by the U. S. Bureau of Mines in their studies of strain measurements in rock. Early in our work we adopted procedures similar to those used by the Bureau of Mines. Strain pulses were measured by gages cemented in boreholes. Since we were primarily interested in the effect of explosives in the zone where fracture might occur, this system offered several disadvantages for Du Pont: 1. Cemented gages were expensive and not reusable. 2. When gage holes were used for several shots, there was considerable question as to the condition of the rock after the first shot.

Jan 1, 1968

By Richard C. Timberlake

The disposal of phosphatic clays has presented a problem to the phosphate industry since the mining of phosphate rock first began in Polk County. As the flotation process was introduced in the late 1920's the problem of clay disposal was increased significantly since clay is present in proportionally greater quantities in reserves yielding flotation concentrates. Because of their physical character and the tremendous surface area per unit volume, these clays have the characteristic of retaining large volumes of water as they are slurried during processing. The disposal of clay and the recovery of a portion of the water require settling areas with a capacity ranging up to 2 cu ft for each cubic foot of phosphate matrix mined. According to a recent study by the Bureau of Mines, the average cost for disposal of these wastes is 24.5[c] per ton of product. This is a major cost of phosphate rock production.

Jan 12, 1969

By Wheeler P. Davey

When metals are subjected to mechanical working, such as rolling, one of the phenomena that take place is a movement of the crystals of the metal into a system or systems of orientation which bear an angular relation to the direction of working. In rolled metal the crystals may orient themselves with respect to the rolling plane or the rolling direction, or both. Direct evidence of the existence of preferred orientations in rolled metal has been obtained by numerous investigators from X-ray patterns of the rolled metal. Most of these workers used a monochromatic pinhole method. Where the degree of preference for a single orientation is high the monochromatic pinhole pattern may be interpreted by a geometrical calculation based on the angular relationships of the planes in the crystal and the diffraction arcs on the X-ray pattern. This process may be aided by the geometrical construction of the locus sphere (Lagenkugel), and reflection circles of Polanyi,l Polanyi and Weissenberg,2 and Mark and Weissenberg,3 and of the plane polar figures (flachenpolfigur) of Franz Wever.4 R. M. Bozorth5 solves X-ray patterns from metals having a single preferred orientation by means of a series of charts which when placed over the X-ray pattern give directly certain angular relationships, between the crystal planes and the surface of the specimen.

Jan 1, 1930

By A. E. Dwight

Lattice parameters were determined for eighteen equiatornic alloys of the CsCl-type structure, ten of which were previously un-reported. It was found that fomation of the CsCl-type structure in binary alloys of the transition elements is largely dependent on position of the elements in the periodic table. The relative size of the two elements was not found to be a controlling factor. A recent paper by Beck, Darby, and Arora1 corre-lates the occurrence of CsC1-type ordered structures with the position of the constituent elements in the periodic table for the first long period. It was also suggested that a definite increase in relative bond strength between unlike atoms occurred when, in binary alloys of iron-group elements, the other component is changed from a chromium-group element, to a vanadium-group element, to titanium. A later paper by Philip and Beck2 noted that the lattice contraction increased in the order CrFe, VFe, and TiFe. It was also noted by Philip and Beck2 that the lattice contractions of CsC1-type alloys decreased in the order: TiFe, TiCo, and TiNi, which is an apparent reversal of the contractions expected from the position in the periodic table. It was suggested that the increasing lattice contraction is an indication of increased stability, i.e., greater A-Bbond strength. The present investigation was carried out to determine whether the relation of the position in the periodic table to the formation of the CsC1-type structure was also correct for alloys involving the second and third long-period elements. A systematic search was made for CsC1-type structures among equiatomic alloys and for those found, the lattice contraction was determined. EXPERIMENTAL TECHNIQUE The elements Y, Gd, Ti, Zr, Hf, V, and Cb are designated the A group and the elements Mn, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, and Au are designated the B group. Equiatomic alloys were prepared for 57 AB combinations. The alloys were arc melted in a multicrucible furnace3 in buttons ranging from 5 to 20 g. Chemical analyses were not made, as the charge weights agreed closely with those of the buttons after melting. The alloy buttons were homogenized at 800° to 900°C. Metal log raphic and X-ray specimens were prepared and heat treated at temperatures from 600° to 1200°C. Specimens for X-ray diffraction were usually ground to a powder in an agate mortar; however, needle-shaped solid specimens were used when the alloy was sufficiently ductile to permit their preparation. Diffraction patterns were taken with a Straumanistype Debye-Scherrer camera using filtered Cu or Co radiation. The lattice parameters were obtained in A by plotting the calculated a0 values against the cos29/sin 0 + cos2?/? function and extrapolating linearly to ?= 900. Metallographic control specimens were polished on cloth wheels with diamond paste and etched with various phosphoric and nitric acid reagents. RESULTS The eighteen equiatomic alloys listed in Table I gave evidence of a cubic structure with two atoms in the unit cell, although two of these cubic structures exist only at elevated temperatures and transform to a tetragonal structure on quenching. Nine of these eighteen alloys gave diffraction patterns with super-lattice lines showing that the structure is of the CsC1-type. The lack of superlattice lines in patterns of the other nine alloys may be attributed to the small difference in atomic scattering power of the components. Metallographic study indicates the occurrence of nine narrow single-phase fields at the AB composition. Any or all of these nine may also have a CsC1-type structure. The VFe alloy was found to have a CsCl-type structure by Philip and Beck2 through the use of CrKa radiation (for which the scattering factor of V is anomalously low), whereas the Cu radiation used

Jan 1, 1960

By Frank A. Herald

Generally in Table 1 the unit for presentation of data is a field. For our purposes a field is defined as the whole of a surface area wherein productive locations are continuous. Such unit commonly includes and surrounds nonproductive areas. Such unit commonly includes a great variety of geologic conditions-—several units of continuous productive reservoirs of distinctly different structure and of distinctly different stratigraphy. Therefore it is hoped that our authors will subdivide "field" so as to enable students to make analyses that may have scientific and /or commercial value. As to each space in the tabulation, it is either (I) not applicable, (2) the proper entry is not determinable, (3) the proper entry is determinable, but not determinable from data available to the author, (4) the proper entry is determinable by the author. In spaces not applicable, the author will please draw horizontal lines; in spaces where the proper entries are not determinable, the author will please insert x; in spaces where the proper entries are determinable but not determinable from data available to the author, the author will please insert y; in spaces where the proper entries are determinable by the author he will, of course, make such entries. Generally, y implies a hope that in some future year a definite figure will be available. Inability to determine precisely the correct entry for a particular space should not lead the author to insert merely y. Contributions of great value may be made by the author in many cases where entries are not subject to precise determination. In such cases the author should use his good judgment and make the best entry possible under the circumstances. For many spaces, the correct entries represent the opinion of the author (for example, "Area Proved") and in such cases the entries need not be hedged to such extent as in cases where the quantities are definite yet can be ascertained only approximately by the author. In cases under definite headings but where figures are only approximate, the author may use 2. For example, if the total production of a field is known to be between 1,800,000 and 1,850,000, the author may report 1,8xx,xxx; or if the production is between 1,850,000 and 1,900,000, the author may report 1,9xx,xxx. Where a numeral is immediately to the left of x or y, such numeral represents the nearest known number in that position. As to quantity of gas produced from many fields the question will arise as to whether the figures should include merely the gas marketed or should include also estimates of gas used in operations and gas wasted. Although rough approximations may be involved, our figures should represent as nearly as possible the total quantity of gas removed from the reservoir. Wile we have not provided a column for showing the thickness of the productive zone, generally the difference between average depth to bottoms of productive wells

Jan 1, 1935

By Elliot P. Rexford

IN the early days of concrete construction, the question of quality of sand or gravel to be used as aggregate in concrete was given little or no consideration. If the construction engineer had sufficient quantity for his structure within a reasonable distance, he was contented and gave no thought to the possibility that the material might have adverse physical, chemical, or thermal properties which could cause future deterioration of his concrete and possible failure of his structure. Today a very different situation exists. With the building of larger and larger concrete structures, with a longer and longer life expectancy, the quality of the aggregate material has become of major importance. Even in small concrete structures aggregate quality cannot be passed off lightly and the quality of the aggregate must be such as to give the anticipated life without costly maintenance. The first question to arise in the selection of an aggregate is what makes a sand or gravel suitable or unsuitable for use in concrete, and how can its quality be judged. No one rock type can be depended upon to furnish sound durable material in all instances. Granitic rocks, for example, make very satisfactory aggregates in some cases, but they are among the most unsuitable of materials when they are fractured, weathered, or highly micaceous. Limestones make excellent concrete aggregates on the one hand, and on the other they may be unsound and lack durability if they contain appreciable clay, they may have a harmful chemical reaction with the cement if they contain amorphous silica, or they may have thermal characteristics which make them highly unsuitable for use in concrete. Each rock, gravel, or sand must be proved on its own merits for the particular job under consideration. The selection of suitable aggregate materials may be divided into two major phases, the geological phase which is carried on largely in the field, and the testing phase which of course is a laboratory problem; both are important. Very often the geological phase alone is sufficient for the selection of satisfactory aggregates for minor structures but for major structures both phases must be thoroughly investigated. Geological Phase In the southwest part of the country nearly every major rock type, igneous, metamorphic, and sedimentary, may be found with all imaginable intermediate phases and in all imaginable stages of alteration. Frequently very different rock types, different as to geological age, composition, and condition occur very close together. Alluvium and stream-bed sands and gravels will consist of many different rock types and even ledge rocks may vary radically as to texture and composition within the area of a quarry site. Some of the rocks make suitable aggregate materials whereas others are highly deleterious in concrete. Too often the good and the bad occur together and more than ordinary caution is required in aggregate selection. Aggregate Sources: Concrete aggregates are usually obtained from stream-bed sands and gravels or from ledge rocks. Each has certain favorable and unfavorable characteristics and it is sometimes necessary to investigate both types to determine the most suitable source for a specific structure. Stream Beds: The predominant sources of aggregate materials in southern California and Arizona are stream beds. Vast quantities of sands and gravels are brought from the mountain ranges by the rivers during times of flood but most of these streams are dry a large part of the time and hence these deposits make easily accessible sources of aggregate materials. From many standpoints stream-bed materials make very acceptable aggregates. The gravel pebbles and the sand grains are

Jan 1, 1951

By Elliot P. Rexford

IN the early days of concrete construction, the question of quality of sand or gravel to be used as aggregate in concrete was given little or no consideration. If the construction engineer had sufficient quantity for his structure within a reasonable distance, he was contented and gave no thought to the possibility that the material might have adverse physical, chemical, or thermal properties which could cause future deterioration of his concrete and possible failure of his structure. Today a very different situation exists. With the building of larger and larger concrete structures, with a longer and longer life expectancy, the quality of the aggregate material has become of major importance. Even in small concrete structures aggregate quality cannot be passed off lightly and the quality of the aggregate must be such as to give the anticipated life without costly maintenance. The first question to arise in the selection of an aggregate is what makes a sand or gravel suitable or unsuitable for use in concrete, and how can its quality be judged. No one rock type can be depended upon to furnish sound durable material in all instances. Granitic rocks, for example, make very satisfactory aggregates in some cases, but they are among the most unsuitable of materials when they are fractured, weathered, or highly micaceous. Limestones make excellent concrete aggregates on the one hand, and on the other they may be unsound and lack durability if they contain appreciable clay, they may have a harmful chemical reaction with the cement if they contain amorphous silica, or they may have thermal characteristics which make them highly unsuitable for use in concrete. Each rock, gravel, or sand must be proved on its own merits for the particular job under consideration. The selection of suitable aggregate materials may be divided into two major phases, the geological phase which is carried on largely in the field, and the testing phase which of course is a laboratory problem; both are important. Very often the geological phase alone is sufficient for the selection of satisfactory aggregates for minor structures but for major structures both phases must be thoroughly investigated. Geological Phase In the southwest part of the country nearly every major rock type, igneous, metamorphic, and sedimentary, may be found with all imaginable intermediate phases and in all imaginable stages of alteration. Frequently very different rock types, different as to geological age, composition, and condition occur very close together. Alluvium and stream-bed sands and gravels will consist of many different rock types and even ledge rocks may vary radically as to texture and composition within the area of a quarry site. Some of the rocks make suitable aggregate materials whereas others are highly deleterious in concrete. Too often the good and the bad occur together and more than ordinary caution is required in aggregate selection. Aggregate Sources: Concrete aggregates are usually obtained from stream-bed sands and gravels or from ledge rocks. Each has certain favorable and unfavorable characteristics and it is sometimes necessary to investigate both types to determine the most suitable source for a specific structure. Stream Beds: The predominant sources of aggregate materials in southern California and Arizona are stream beds. Vast quantities of sands and gravels are brought from the mountain ranges by the rivers during times of flood but most of these streams are dry a large part of the time and hence these deposits make easily accessible sources of aggregate materials. From many standpoints stream-bed materials make very acceptable aggregates. The gravel pebbles and the sand grains are

Jan 1, 1951

By Fred Witt, Milton Schwartz

ESTABLISHED methods for obtaining quantitative pole figures for flat sheets1"5 can be extended to apply to thin films on a substrate. The mode of scanning the sample is exactly the same as described in the references? but consideration is given to the fact that the scattered X-ray intensities are due to both the thin film and its substrate with appropriate attenuation factors. The purpose of this paper is to describe a method to obtain the scattered intensities from the film alone for subsequent pole-figure determinations. Fig. 1 shows the four possible general positions of the film (f) and its substrate (s) with respect to the incident X-ray beam (I,). In this paper it will be assumed that the plane of the sample is normal to the plane of the diffractometer. In the diagrams the line jV is the normal to the flat sample and the line P is the trace of the diffracting crystallographic planes in the plane of the diffractometer. The angle of tilt, a, is the positive acute angle measured from the line N to the line P; if this angle is measured clockwise then a is said to be in the positive a region; if this angle is measured counterclockwise then a is said to be in the negative a region. For the reflection cases, the total scattered intensity, at the proper Bragg angle for a particular set of planes, is due to that scattered by the film Vf) and that scattered by the substrate. The beam incident on

Jan 1, 1967

By C. O. Dale, W. J. Rundle

THE upper Mississippi Valley zinc-lead area was the first major lead-producing section in the United States. The lead ore, found near the surface in crevices, was relatively pure galena that could be smelted directly into lead, at first in log hearth furnaces and later in more efficient blast type furnaces. French Canadian fur traders encouraged the Indians to mine the lead ore and showed them how to smelt it into lead that had a high value for bullets1 Nicholas Perrot found lead ore on the Mississippi River bluffs near the junction of Wisconsin and Illinois and in 1690 established a trading post on the Wisconsin side of the river opposite the present site of Dubuque, Iowa.2 Shortly after 1720 discovery of Mine La Mott in Missouri diverted considerable attention from the Upper Mississippi area. Mining continued on a desultory basis with operations concentrated in the Galena, Illinois-Dubuque, area. In 1740 at least 20 miners were at work in the Fever River area around Galena and are reported to have shipped 2500 70-lb pigs of lead to Kaskaskia in 1741." Julien Dubuque established a mining and smelting operation in 1790 near the city that bears his name and was granted sole right to exploit the mining operations on the lands of the Sauk and the Fox Indians. He is reported to have produced 30,000 70-lb pigs of lead in 1805. Following the death of Dubuque in 1810 the Indians refused to let the white miners enter their lands, and little was done on the Iowa side of the river until the Indians were removed by treaty with the United States government in 1832." Early mining was entirely for lead but as the crevices were followed down, increasing percentages of zinc sulphide and zinc carbonate were encountered and at first discarded. Later a market became available for the zinc ores, and hand jigging devices were made to separate the lead, the zinc, and the rock or waste materials. The first record of zinc production from the area is for 1860. Production of zinc passed that of lead before 1900, reached a peak of 64,000 short tons in 1917, fell off rapidly and continually to about 2000 short tons in 1938, and since 1940 has ranged from 11,000 to 19,000 short tons. Lead has been of considerably less importance since 1900, and at present only about 10 pct as much lead as zinc is produced. Practically all of the zinc ore has come from orebodies that are rather flat and wide with considerable length as compared to width. Most of the early lead came from the crevice type deposit, but present production is from the predominately flat zinc orebodies. The Graham-Snyder orebody, scene of Eagle Picher operations, is practically all zinc with little or no lead being recovered. Marcasite, present in varying amounts, makes production of finished concentrates by gravity separation impractical. Satisfactory lead and zinc concentrates have been produced since flotation was introduced in the area in 1927. An acid recovery plant was operated for about 20 years after World War I, but it has been dismantled, and no recovery of the iron sulphides in the ores of the district is being made at the present time. In June 1950 there were three companies operating mines and mills, Tri-State Zinc Co., Calumet & Hecla Consolidated Copper Co., and Eagle Picher Mining and Smelting Co. The Vinegar Hill Zinc Co. had completed a shaft at a new orebody and had started to develop the mine which will supply the Cuba City mill. The Cuba Mining Co. was holding the Andrews Mine inactive. The Dodgeville Mining Co. was not operating but was exploring for additional reserves. Several small mines were selling ore to the Eagle Picher mill. A general area map is given in Fig. 1. The Eagle Picher Mining and Smelting Co. entered the area in 1946 with an active exploration campaign. Leases on a block basis were secured for the area south from the Wisconsin-Illinois line near

Jan 1, 1953

By C. O. Dale, W. J. Rundle

THE upper Mississippi Valley zinc-lead area was the first major lead-producing section in the United States. The lead ore, found near the surface in crevices, was relatively pure galena that could be smelted directly into lead, at first in log hearth furnaces and later in more efficient blast type furnaces. French Canadian fur traders encouraged the Indians to mine the lead ore and showed them how to smelt it into lead that had a high value for bullets1 Nicholas Perrot found lead ore on the Mississippi River bluffs near the junction of Wisconsin and Illinois and in 1690 established a trading post on the Wisconsin side of the river opposite the present site of Dubuque, Iowa.2 Shortly after 1720 discovery of Mine La Mott in Missouri diverted considerable attention from the Upper Mississippi area. Mining continued on a desultory basis with operations concentrated in the Galena, Illinois-Dubuque, area. In 1740 at least 20 miners were at work in the Fever River area around Galena and are reported to have shipped 2500 70-lb pigs of lead to Kaskaskia in 1741." Julien Dubuque established a mining and smelting operation in 1790 near the city that bears his name and was granted sole right to exploit the mining operations on the lands of the Sauk and the Fox Indians. He is reported to have produced 30,000 70-lb pigs of lead in 1805. Following the death of Dubuque in 1810 the Indians refused to let the white miners enter their lands, and little was done on the Iowa side of the river until the Indians were removed by treaty with the United States government in 1832." Early mining was entirely for lead but as the crevices were followed down, increasing percentages of zinc sulphide and zinc carbonate were encountered and at first discarded. Later a market became available for the zinc ores, and hand jigging devices were made to separate the lead, the zinc, and the rock or waste materials. The first record of zinc production from the area is for 1860. Production of zinc passed that of lead before 1900, reached a peak of 64,000 short tons in 1917, fell off rapidly and continually to about 2000 short tons in 1938, and since 1940 has ranged from 11,000 to 19,000 short tons. Lead has been of considerably less importance since 1900, and at present only about 10 pct as much lead as zinc is produced. Practically all of the zinc ore has come from orebodies that are rather flat and wide with considerable length as compared to width. Most of the early lead came from the crevice type deposit, but present production is from the predominately flat zinc orebodies. The Graham-Snyder orebody, scene of Eagle Picher operations, is practically all zinc with little or no lead being recovered. Marcasite, present in varying amounts, makes production of finished concentrates by gravity separation impractical. Satisfactory lead and zinc concentrates have been produced since flotation was introduced in the area in 1927. An acid recovery plant was operated for about 20 years after World War I, but it has been dismantled, and no recovery of the iron sulphides in the ores of the district is being made at the present time. In June 1950 there were three companies operating mines and mills, Tri-State Zinc Co., Calumet & Hecla Consolidated Copper Co., and Eagle Picher Mining and Smelting Co. The Vinegar Hill Zinc Co. had completed a shaft at a new orebody and had started to develop the mine which will supply the Cuba City mill. The Cuba Mining Co. was holding the Andrews Mine inactive. The Dodgeville Mining Co. was not operating but was exploring for additional reserves. Several small mines were selling ore to the Eagle Picher mill. A general area map is given in Fig. 1. The Eagle Picher Mining and Smelting Co. entered the area in 1946 with an active exploration campaign. Leases on a block basis were secured for the area south from the Wisconsin-Illinois line near

Jan 1, 1953

By David Mitchell

THE production of fluorspar is one of the smaller nonmetallic indus-tries in the United States with a capital investment-about $10,000,000. Shipments from United States mines' in 1936 totaled 176,231 short tons valued at $3,111,268, an average price of $17.65 per ton. The United States produces about 40 per cent of the world's fluorspar, of which about 90 per cent comes from the Illinois and Kentucky deposits along the Ohio River.2 Further detailed information on the fluorspar industry in the United States is given by Hatmaker and Davis.28 Fluorspar is marketed according to the following relative quantities and specifications: Consump- Specifications, Per Cent Use Form tion in 1936, Per Cent CaF2 SiO2 Fe2O3 Metallurgical Gravel 79 +85 -5 or lump Ceramic,. Ground 10 +95 -3 -0,1 Acid Ground 11 +98 -1 The concentration of the coarser sizes presents relatively little diffi-culty, good recoveries being obtained with jigs and tables. However, sizes smaller than about 10 mesh cannot be successfully treated by ordinary gravity separation methods and so have been accumulating as

Jan 1, 1938

By R. A. Kinzie

THE major operating costs in a cement plant are labor, power, and fuel. The opportunities and methods of savings in labor and power parallel other industries. Because our industry's use of fuel is large and its method of use is unique, the devices adapted for saving fuel are of interest. In normal practice the raw material in the form of a dry powder or a mud is fed to a rotating inclined cylinder where it is dried, calcined, and clinkered. In a Lepol kiln the raw material is rolled up into little balls with water in the nodulizer, fed to a traveling grate on which it is dried and partially calcined and tben to a short kiln where the process is finished. The more usual methods of saving heat have been the use of long kilns with chains in wet process plants and the use of waste heat boilers in dry plants (fig. 1). At the Santa Cruz plant we have used a Lepol system kiln and achieved a fuel 'economy of 4.7 gal per bbl of clinker or about 704,-000 Btu per bbl. This can be compared with our old kilns using the same fuel and raw material which consume 7.8 gal per bbl or 1,130,000 Btu per bbl. These are gross Btu and not the net figures usually used in reports of foreign companies. Our average consumption for 1948 was 708,000 Btu per bbl of Lepol clinker, based on cement sold, and oil purchased. The overall fuel consumption for 1948 was 6.61 gal per bbl. The Lepol system consists of a nodulizer, a grate, and a kiln. There is the usual accessory equipment which is similar to that used in other cement plants. The following description covers the equipment in operation at our plant. The nodulizer is a cylinder 8 ft 10 in. in diam by 18 ft long set on a slope of 1/2 in. per ft, and rotated at about 10 rpm. It is driven by a 50 hp wound rotor motor drawing about 9 kw. The inside of the shell is cleaned by a continuously operating scraper which draws 0.1 kw. The dry raw material is fed to the nodulizer where, being sprayed with water, it rolls into small spheres about 90 pct being between 1/2 and 1 in. in diam and containing about 15 pct water. The nodules fall on the traveling grate where the hot gas from the kiln is pulled down through the

Jan 1, 1951

By R. A. Kinzie

THE major operating costs in a cement plant are labor, power, and fuel. The opportunities and methods of savings in labor and power parallel other industries. Because our industry's use of fuel is large and its method of use is unique, the devices adapted for saving fuel are of interest. In normal practice the raw material in the form of a dry powder or a mud is fed to a rotating inclined cylinder where it is dried, calcined, and clinkered. In a Lepol kiln the raw material is rolled up into little balls with water in the nodulizer, fed to a traveling grate on which it is dried and partially calcined and tben to a short kiln where the process is finished. The more usual methods of saving heat have been the use of long kilns with chains in wet process plants and the use of waste heat boilers in dry plants (fig. 1). At the Santa Cruz plant we have used a Lepol system kiln and achieved a fuel 'economy of 4.7 gal per bbl of clinker or about 704,-000 Btu per bbl. This can be compared with our old kilns using the same fuel and raw material which consume 7.8 gal per bbl or 1,130,000 Btu per bbl. These are gross Btu and not the net figures usually used in reports of foreign companies. Our average consumption for 1948 was 708,000 Btu per bbl of Lepol clinker, based on cement sold, and oil purchased. The overall fuel consumption for 1948 was 6.61 gal per bbl. The Lepol system consists of a nodulizer, a grate, and a kiln. There is the usual accessory equipment which is similar to that used in other cement plants. The following description covers the equipment in operation at our plant. The nodulizer is a cylinder 8 ft 10 in. in diam by 18 ft long set on a slope of 1/2 in. per ft, and rotated at about 10 rpm. It is driven by a 50 hp wound rotor motor drawing about 9 kw. The inside of the shell is cleaned by a continuously operating scraper which draws 0.1 kw. The dry raw material is fed to the nodulizer where, being sprayed with water, it rolls into small spheres about 90 pct being between 1/2 and 1 in. in diam and containing about 15 pct water. The nodules fall on the traveling grate where the hot gas from the kiln is pulled down through the

Jan 1, 1951

By J. D. Audley Smith

Heine's " blue test" for copper, as described by the authorities generally, calls for a set of standard colors; and there has been some discussion concerning the relative superiority, for this purpose, of sulphate and nitrate solutions. The whole matter evidently hinges on the preservation of the standard colors in well-stoppered bottles. The apparatus described by Q. L. Heath* cannot be much improved, when very accurate readings are required. The following method was devised for the purpose of doing away with preserved sets of standard colors, by making a fresh standard for each batch of assays. The solutions are prepared in the usual way, each ammoniacal solution being filtered into its separate bottle, and then filled up to the containing-mark and thoroughly mixed. A similar color-bottle, with an " S " etched upon it, to distinguish it from the other bottles, which are numbered to correspond with the samples, is kept to run the standard. About 150 C.C. of water is put into it, and then the amount of acid (sulphuric or nitric) present in each determination, followed by 30 C.C. of ammonia (s. g. 0.90), which should make the mixture strongly ammoniacal. The liquid is now made up almost to the containing-mark (200 c.c.), say within 1 C.C. The lowest assay is selected first and placed alongside the standard, which, at the beginning, contains no copper. A copper-solution is then dropped into the standard from a burette ; and after each addition the bottle is well shaken and compared with the assay-sample. This operation is repeated until the two shades match exactly, when the burette is read and the assay-result is calculated. The assay next in order of depth of color is now taken and treated in the same way, and so on, until the batch is completed. It

Jan 1, 1901

By Gordon H. Geiger, J. Bruce Wagner

Electrical conductavity and therrnoelectvic nzeasuretnents on synthetic hematite slabs with 0.01 to 0.90 at. pet Ti and with 0.30 at. pet Ca were made. Additions of titanium and of calcium both increased the electronic conductivity with titanium yielding greater n-type behavior and calciurn p-type behavior. Reduction studies of hematite to magnetite in CO-CO2 atmospheres between 600° and 900°C initially exhibited linear kinetics. These linear rates were increased by additions of titanium and decreased by calcium. IN recent years many studies have been reported in the literature on the kinetics of the reduction of hematite and magnetite to iron. In addition, Hansen and Josephl and Schenck and Schultz2 have reported studies on the reduction of hematite to magnetite, the first step in total reduction to iron. In order to evaluate the results of the studies of over-all reduction in terms of the actual mechanism of the reaction and to define further the important factors in the rate- controlling mechanism of the magnetic roasting reaction, the following experiments were undertaken. Specimens of undoped hematite and hematite containing titanium or calcium in solution as doping agents were reduced to magnetite in CO-CO2 mixtures. In addition, electrical-conductivity measurements were correlated with the reduction kinetics using concepts of defect solid-state chemistry. EXPERIMENTAL Fisher certified Fe2O3 powder was used to make specimens for both the electrical and kinetic studies (see Table I for analysis). Doping with titanium and calcium was accomplished by adding TiO2 and CaO powders to the Fe2O3 powder. The powders were mixed in a Waring blender for minimum times of 1/2 hr. Satisfactory blending was achieved based on comparison of analyses of individual specimens af- ter reduction. The specimens were formed in a steel die using opposed punches with a rectangular opening 10.0 by 40.0 mm. The Fe2O3-TiO, platelets were pressed cold at 16,000 psi. They were sintered for approximately 16 hr at 1075°C in air, in accordance with information in the literature3, 4 on the time and temperature needed to obtain solution of the titanium in the hematite. The Fe2O3-CaO mixtures were first cold-pressed at 20,000 psi and sintered for 3 hr at 1225°C to insure solution of CaO. This material was then ground to -325 mesh in a 6-in. ball mill and the resulting powder was used to make platelets in the same manner as above. The sintered platelets were usually between 1/16 and 1/8 in. thick. They were ground on a carborundum wheel and polished on 2/0 paper. Typical dimensions of the kinetic-study specimens were 1.6 by 0.8 by 0.05 cm, and a typical weight was 0.3 g. Conductivity and thermoelectric specimens were approximately the same size, but were subjected to further sintering in order to ensure maximum densification. Finally, all specimens were measured to the nearest 0.0005 in. and weighed on a Mettler H-15 balance to the nearest 0.0001 g and the density calculated. The average density of the specimens used for the reduction studies was 4.87 g per cc, or 7.1 pet total porosity. The standard deviation ranged from 0.14 to 0.063 g per cc within a composition group. In the present study, the apparent surface area as measured with a micrometer was taken as the true surface area. The chemical analyses for calcium and for titanium within a group showed maximum variations of 50.04 pet from the average values used in Figs. 9 and 11. In order to suspend the specimen from the balance for the kinetic studies, a hole, 0.03 in. in

Jan 1, 1965

By D. Weinstein, F. C. Holtz

AS a possible method of improving the elevated temperature strength properties of zirconium, an investigation was initiated on the feasibility of producing a dispersion-strengthened material. Because of the high reactivity of zirconium, its high solubility for oxygen, and the stability of the Zr-0 solid solution, the major problem in such a development is choice of a suitable dispersant. Thus, in the present investigation we were concerned primarily with the stability of various dispersants in the zirconium matrix. The experimental procedure consisted of blending powders of zirconium and a dispersant, followed by cold compaction and extrusion. The best available source of -325 mesh zirconium powder contained between 1500 and 3500 ppm Oz; to this material, powders of zirconium carbide (5 p max), vanadium carbide (5 p max), alumina (0.03 p average), lan-thana (0.8 to 2 p), ceria (0.8 to 2 p), yttria (0.8 to 2 p), calcia (44 p rnax), or thoria (0.6 to 0.8 p) were added in amounts of 7 vol pct and compacted at 65 tsi. A cylindrical compact having a density between 70 and 80 pct of theoretical and dimensions of 1 in. diam by 1-114 in. high was thus produced. After canning in copper, these billets could be extruded (5: 1) on a 54-ton capacity, slow-traverse hydraulic press with the billet temperature at 1550°F and the extrusion die at 900°F. However, lack of densifica-tion of some of the extruded billets necessitated ratios of at least 23 :1. Ultimately, all billets were successfully extruded at 1500°F to 0.190 in. diam (32 :I), fully dense rods using a 200-ton capacity press and a ram speed of 90 ipm. The microstructures of as-extruded Zr-7 vol pct LazOS and Zr-7 vol pct Y2Os are shown in Fig. l(a) and (c), respectively. These structures are similar to all the as-extruded materials and consist of an elongated, single-phase zirconium matrix dispersed with oxide or carbide particles. Very little porosity is observed, and the interface between matrix and particles appears satisfactory. The size and distribution of particles, however, are not ideally of the type desired for dispersion strengthening. Since the primary study was of particle stability with respect to zirconium, no attempt was made to overcome agglomeration during powder blending and fabrication. Some areas exhibit fine, well-distributed particles; undoubtedly, a small proportion is submicroscopic and has the

Jan 1, 1963

By H. W. Mossman

Three aspects of magnetite smelting are discussed. The first is the working out of equilibrium conditions for eliminating sulfur. The second is the influence of magnetite solubility on the difficulty of tapping the reverb matte. The third is an approximation of the equilibrium conditions in the reverb gases which govern whether magnetite is mode or reduced in the reverb slag by these gases and by any iron sulfide in the slag. MAGNETITE has had a varied history in the Hurley Smelter since its start in 1939. Magnetite determinations on the smelter products are made regularly only on the monthly composite samples. Variations on the monthly averages are shown in Table I. Magnetite which drops from the slag and matte in the reverb has some slight bottom buildup which comes and goes, but no substantial accumulation from this source has been found at the end of a normal nine months' furnace campaign. However, there has been some low grade magnetite bearing material mixed with considerable A1,0,, which has slid down from the bottom of the sloping flue between the reverberatory furnace and the waste heat boilers. This accretion has required drilling and blasting near the skimming end of the furnace. The magnetite has interfered with tapping at times. When the smelter was first started, tapping trouble from magnetite was extremely severe. Increasing the reverberatory furnace temperature by putting in an air preheater and a Dutch oven has helped greatly, although there still is occasional tapping trouble. When the present series of physical chemistry articles on copper smelting started coming out in 1950, they were read with interest, but no immediate application was seen for them. Results of some laboratory work in 1952 aroused a much stronger interest in this physical chemistry. A series of melts was made on some converter slags, which had magnetite in very large grain sizes, with the object of reducing the grain sizes in the slag, as it was known that it was easier to handle in the reverb in that condition. Anything done in the tests greatly reduced the grain sizes—even in the controls, where nothing was done except melt the slag and cast it. There was more magnetite in the slags after the tests than before, and with wide variations. There were no obvious reasons lor much of what happened in these tests. Much of the base material published in English in this field was made available for study. Recalculations were made on many of the type problems, and part of the data was reduced to local temperatures and compositions. Explanations were found for what happened in the 1952 series of tests on converter slags, and the same principles turned out to be a description of much of what magnetite does in the reverb. This article is to present the results of that study, from the viewpoint of applying the technical material in definite numerical form to the operating conditions in both the converters and the reverberatory furnaces at the Hurley smelter. Table I. Magnetite Variations on Monthly Averages, 1939 to 1955 Pet Magnetite Lowest Highest Average Converter slag 13.6 43.3 25.4 Roverb slaa 2.7 20.9 8.7 Matte 28 15.9 98 In general it was found that magnetite is made or reduced in both the converters and the rever-beratory furnace, depending on variations of temperature, matte composition, and reverb gas composition occurring in ordinary plant operation. Within reasonable limits, the field conditions for formation or reduction can be predicted, and probably can be set up and maintained. Converter conditions affecting magnetite formation can be put into numerical values better than for the reverb from purely technical calculations. The converter can be operated so as to keep the magnetite in the slag down to between 12 and 14 pct and still give satisfactory life for the converter brick. This depends upon having converter flux available which will make a slag with a good separation without raising the temperature too high. In the Hurley reverb and others with similar conditions, it is likely that a compromise of conditions will give a reasonably good control of combustion and still keep the magnetite from building up on the bottom. This discussion consists of three main parts. The first is the working out of the equilibrium conditions in the converter for determining in which direction the reaction 3 Fe,,O, (s) + FeS (1) F? 10 FeO (1) + SO, will go under actual converter operating conditions. The second deals with the influence of the solubility of magnetite in the slag and matte in the reverb on the difficulty of tapping matte. The third is an approximation of the equilibrium conditions in the

Jan 1, 1957