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By I. E. Puddington

The property of surface tension in liquids is said to have been known to Leonardo de Vinci in about 1500. Approximately'300 years later Thomas Young and others provided the ground rules relating surface tension to the wetting of solids and to the pressure drop across curved surfaces. In retrospect it seems remarkable that more than 100 additonal years were required for substantial technological use to be made of the-information. Thus super critical and freeze drying to avoid shrinkage of finely divided solids have only seen industrial use since the 1930's and doubtless additional possible applications will be equally slow in finding concurrence of conditions to make them attractive economically. The use of a second liquid phase that preferentially wets ,a suspended solid as a flocculant for that solid was pointed out in 1943 (1). Combining this phenomenon with mechanical energy to alter the morphology of the flocs or with surface chemistry to utilize it in the selective flocculation in mixed solids required more than an additional decade. A major stimulant in advancing surface energy based technology 'of suspensions was the report by D. I. Stock in 1952 (2) that mechanical agitation of a dry suspension of barium sulphate in benzene produced dense microspheres of the solid with highly desirable sedimentation characteristics. Investigation of this observation revealed that it resulted from small quantities of water in the system and mechanistically the phenomenon was identical with that reported in 1943.withthe addition of mechanical packing (3). Here then was a base from which to separate more efficiently suspended solids, to make small spheres from powders, to separate selected components from mixtures of finely divided solids or to break emulsions. Each of these possible branches of technology has been slow in developing on other than an experimental scale although considerable

Jan 1, 1979

By R. T. Southin

Cast ingots of 99.99 pct purity A1 and aluminum/copper alloys containing up to 2 pct Cu have been found to contain four zones rather than the three previously accepted, i.e., chill, colummar, and equiaxed zones. The fourth zone consists of a coarse dendritic layer across the top surface of the ingot which is open to the atmosphere. It is also found that the grains in the equiaxed region have a "cornet" shape, with a head which is coarsely dendritic and a tail which grew with the same structure as the columnar grains. Experiments using mechanical barriers, and others involving the elimination of the surface dendrile layer, have indicated that nucleation of the equiaxed zone is caused by the showering of dendritic particles from this surface dendrite layer. These particles are the dendritic heads found in the comet grains. A mechanism of nucleation and growth of these comet grains is put forward. Experiments with a number of other metals and alloys suggests that these conclusions may apply generally to ingots cast without the addition of nucleating agents, and solidified under normal conditions. THE macrostructure of cast ingots may contain the following three zones: i) a peripheral zone of fine equiaxed grains, commonly called the chill zone; ii) a zone of columnar grains extending inwards from the chill zone; iii) a central zone of equiaxed grains; these are normally larger than the chill grains. All three zones are not necessarily present in any particular ingot since their existence and magnitude depend upon the casting conditions and composition of the cast material. The mode of formation of zones i and ii is fairly well understood. However, the cause of the central equiaxed zone remains a matter of conjecture. Previous theories put forward to explain the mechanism of nucleation in the equiaxed zone have been examined by Chalmers1 and Winegard.2 At the time when the present work was carried out the most re -cent hypothesis was that due to Chalmers,1 who recognized more fully than previous workers that conditions in this zone during solidification were not conducive to nucleation. In his hypothesis, he suggested that nuclei were formed near the mould wall during the very early stages of solidification, and that they can drift into the central zone by convective motion. This was supported by evidence from experiments using mechanical barriers to stop the drift of nuclei. A similar hypothesis had previously been put forward by Genders.3 More recently, Jackson et al. 4 have observed that dendrite arms in organic compounds can melt off during solidification. They have postulated that this occurs in metals and alloys, and that the dendrite arms which have been freed from the main dendrite act as nuclei for the equiaxed zone. In the present work, critical metallographic examination has shown that there is a fourth zone in the macrostructure of cast ingots which is a dendritic layer over the top surface of the ingot. It is also shown that there is a relationship between this zone and nucleation of the equiaxed zone. EXPERIMENTAL DETAILS The alloys examined were prepared from super -purity aluminum of 99.99 pct min purity (spectro-graphically detected impurities of Cu, Fe, Si, and Mg) and copper of 99.98 pct min purity (spectrographically detected impurities of Si, Zn, As, Fe, Pb, Bi, Ni, Sn, Mn, Ag, Cr, and Al). Three compositions of ingots were examined, containing 0.0, 0.1, and 2 pct Cu, respectively. The alloys were melted in an alumina-lined salamander crucible using a medium-frequency electric induction furnace; when the appropriate casting temperature was reached, the alloys were cast without degassing or fluxing treatment. The mould used was made of electrode graphite and had the following dimensions: external diameter 6 in., height 9 in., with a mould cavity 8 in. deep and a diameter tapering from 5 in. at the top to 4 in. at the bottom. Casting temperatures used were generally in the order of 70" to 90°C above the liquidus and the mould was at room temperature before casting. Inserts kere placed in the mould cavity in some experiments. These consisted of either an 18-g stainless-steel tube of 2 in. diam held axially in the mould i in. off the bottom and extending 1 in. out of the top of the mould or a "trap-door" barrier of stainless-steel gauze of 24-mesh held horizontally in the mould 31/2 in. down from the top. The construction of this insert is shown in Fig. 1. All inserts were preheated prior to casting to prevent chilling. RESULTS The macrostructures of ingots of the three compositions are described, in terms of the three generally recognized zones, in Table I, and illustrated in Figs. 2(a) to (c). The most interesting observation in this table is that relating to the shape of the equiaxed grains, which were not in fact equiaxed but of almost tear-drop shape. Closer examination of these grains showed that each consisted of a head which had a coarse dendritic structure and a tail which always grew in the opposite direction to heat flow, and which had the same structure as that of the columnar material of the ingot concerned; i.e., in the pure aluminum and 0.1 pct Cu alloy it was cellular and in the 2 pct Cu alloy it was cellular-dendritic. Identification of original cast grains was greatly hampered in the super-purity aluminum ingots, and to a lesser degree in the 0.1 pct Cu alloy,

Jan 1, 1968

By I. N. Knapp

I Herewith present some notes on the use of Portland cement to cement in the casing, and for plugging, to exclude water from oil and gas wells, and the methods employed. I have used my best efforts to. make each step of the operation of cementing wells perfectly clear. The information is the result of actual experience and observation. The illustrations are from original drawings made especially for this paper. Portland Cement It is not necessary to discuss here the manufacture of cement. Any established brand of the slower setting Portland cements may be purchased with the confidence that it will harden, if properly used, and exclude water from and plug wells efficiently. Setting.—By the setting of cement is meant its initial change from a soft or plastic mortar to a friable solid. After the cement has become thoroughly set it is still very weak and can be readily pulverized in the fingers. Setting is thought to be effected by the crystallizing out of the silicate and the aluminate of lime, which are soluble in water in their anhydrous form. After dissolving in the water they pass to the hydrated state, in which they are insoluble, and hence are precipitated in a crystalline form. Ordinarily neat Portland cement mortar remains perfectly plastic for from 1 to 1 1/2 hr. after mixing with water at about 70" F. A higher temperature accelerates and a lower retards setting.. Hardening.—This is due to a continual crystallization of salts from solution, and to further chemical and physical changes which develop slowly, but which continue for long periods of time. Testing.—It is no more necessary for an operator to go into the scientific testing of cement to be used in a well than to so test the pipe used. He must depend for the quality of each on the tests and reliability of the manufacturer. Cement or pipe may be damaged in shipment so

Jan 1, 1915

By G. Derge, Lo Ching Chang

The chemical and physical propertties of slag systems are of special interest to metallurgists, for nearly all metals are in contact with molten slags during the primary reduction from their ores and then during the subsequent refining and alloying processes that determine their ultimate use. These processes are carried out at high temperatures and involve such complex chemical systems that funda-mental scientific knowledge of the Properties and behavior of these slags is inadequate. Various hypotheses have been Proposed to explain known slag characteristics. The commonest of these regard the molten slag as constituted of compounds that are dissociated in varying degrees into their constituent oxides, as illustrated by Schenckl and the recent Papers of Chipman and co-authors. Another proposal is that these compounds dissociate by com-plete6 or partial ionization, the evidence for which has been reviewed by Martin and Derge.? whatever hypothesis is favored, the exact formulation of these compounds is incomplete. It is based on three principal types of information: 1. Studies of solidified 51% samples by X ray diffraction, petrography, and similar methods that can be used at room temperature. The correlation of this information with the high-temperature properties of the molten slag is uncertain. 2. Studies of slag-metal equilibria, which have the advantage of providing observations on the molten slag at high temperature. However, even these data present problems of interpretation because they require a complete knowledge of the metal phase. 3. Direct measurements of properties of molten slag at the temperature of greatest metallurgical interest. Viscosity, electrical conductivity, specific heats, and similar properties have been measured, but the data of this type are widely scattered and frequently difficult to interpret. Additional direct measurements of properties of molten slag that can be interpreted in terms of chemical behavior are required, and this paper shows that the standard physical-chemical measurement of reversible electrode potentials, which measure the activity of specific constituents, is a fruitful source of such information. The purpose of this investigation, therefore, was to find an electrode combination that would yield reversible electromotive force measurements when dipped into the molten slag to be studied. Slags of the systems cao-sio2 and cao-120,-SiO2 were chosen for study because graphite containers could be used and the data could be correlated with those for viscosity, conductivity, and other proper-

Jan 1, 1948

By G. Derge

The chemical and physical propertties of slag systems are of special interest to metallurgists, for nearly all metals are in contact with molten slags during the primary reduction from their ores and then during the subsequent refining and alloying processes that determine their ultimate use. These processes are carried out at high temperatures and involve such complex chemical systems that funda-mental scientific knowledge of the Properties and behavior of these slags is inadequate. Various hypotheses have been Proposed to explain known slag characteristics. The commonest of these regard the molten slag as constituted of compounds that are dissociated in varying degrees into their constituent oxides, as illustrated by Schenckl and the recent Papers of Chipman and co-authors. Another proposal is that these compounds dissociate by com-plete6 or partial ionization, the evidence for which has been reviewed by Martin and Derge.? whatever hypothesis is favored, the exact formulation of these compounds is incomplete. It is based on three principal types of information: 1. Studies of solidified 51% samples by X ray diffraction, petrography, and similar methods that can be used at room temperature. The correlation of this information with the high-temperature properties of the molten slag is uncertain. 2. Studies of slag-metal equilibria, which have the advantage of providing observations on the molten slag at high temperature. However, even these data present problems of interpretation because they require a complete knowledge of the metal phase. 3. Direct measurements of properties of molten slag at the temperature of greatest metallurgical interest. Viscosity, electrical conductivity, specific heats, and similar properties have been measured, but the data of this type are widely scattered and frequently difficult to interpret. Additional direct measurements of properties of molten slag that can be interpreted in terms of chemical behavior are required, and this paper shows that the standard physical-chemical measurement of reversible electrode potentials, which measure the activity of specific constituents, is a fruitful source of such information. The purpose of this investigation, therefore, was to find an electrode combination that would yield reversible electromotive force measurements when dipped into the molten slag to be studied. Slags of the systems cao-sio2 and cao-120,-SiO2 were chosen for study because graphite containers could be used and the data could be correlated with those for viscosity, conductivity, and other proper-

Jan 1, 1948

The total crude production from the Dutch East Indies, and the British Protectorates of Sarawak and Brunei for 1932 is given in the following table: Production, which had shown a rapid increase from 1921 to 1929, has since been reduced. Exploitation drilling in the majority of the larger fields was suspended and existing production kept within predetermined limits by beaning. Most of the smaller fields were shut down entirely. The depth of producing levels varies widely in the different fields. Shallow fields with drilling depths to 500 meters (1650 ft.) are still numerous as well as those with depths between 500 and 1000 m. (3300 ft.). A few of the newer fields reach greater drilling depths up to 1600 m. (5250 ft.). The deepest exploration well drilled to date (Djambi field, South Sumatra) reached a, depth of 2332 m. (7650 ft.) before abandonment in March, 1930. The specific gravities of the various crude oils produced range between 0.65 (86.2° A.P.I.) and 0.95 (17.5° A.P.I.). The lighter crudes have a high gasoline content and fuel oils are derived from the heavier crudes, which usually are rich in paraffin. Producing companies are: De Bataafsche Petroleum Maatschappij (Royal Dutch-Shell combine in Dutch territory); The Anglo-Saxon Petroleum Co. Ltd. (Royal Dutch-Shell combine in British territory); De Nederlandsch-Indische Aardolie Maatschappij (De Bataafsche Petroleum Maatschappij-Dutch East Indian Government combine); De Nederlandsche Koloniale Petroleum Maatschappij (Standard Oil Co. of

Jan 1, 1933

By Richard H. Terhune

The use of water-cooled breast-jackets or cinder-tap blocks is a great convenience in lead-smelting, even when siliceous slags are made. If the charges are at all basic it is almost imperative. Jackets of riveted wrought-iron or steel are expensive; those of cast-iron are liable to crack; those of bronze are costly and not durable, being easily penetrated by tapping-bars or destroyed by streams of matte impinging against them. To overcome these objections I introduced at the Hanauer works, in April, 1886, castjackets of steel, which have been in constant use since that time and are to-day as good as new. These jackets were made for us by the Chester Steel Castings Company, of Chester, Pa., at a cost of ten cents a pound at the works of that company. The metal is 5/8-inch thick, and the jackets were cored and tapped for l1/2-inch bushings, affording two large holes for the removal of dirt and incrustations. The same holes are used for feed- and discharge-water through 3/4-inch pipe. I hope the successful introduction here of cast-jackets of steel will lead to their more extended use in all branches of metallurgy where water-cooled surfaces are severely taxed, and where the size and thickness of the castings are not unfavorable to the production of a sound article, impervious to water and of high tensile strength.

Jan 1, 1889

By Bunting S. Crocker

In the summer of 1961, the Anaconda Research staff and Kilborn Engineering Ltd. began a study to investigate the possibilities of using some form of autogenous grinding in the new concentrator which Anaconda was planning to erect at Butte, adjacent to their Berkeley pit. The following criteria applied to the project: 1) The Butte mill was to be able to handle 36,000 to 42,000 tpd of copper ore, taken from the Berkeley pit and adjacent underground mines. 2) The plant was to be built in six units. 3) It would be started up two units at a time. 4) Equipment from the Anaconda mill was available for use in the new location. 5) Tonnage would be maintained at Butte and Anaconda, with equipment being moved down as required. 6) The ore from the Berkeley pit was known to vary widely from place to place in the pit and to be generally soft and friable.

Jan 5, 1964

By N. A. DeCecco, H. M. Meyer

IN the early stages of a titanium brazing investigation, binary titanium systems partially or completely known and fundamental metallurgical data were surveyed to select the pure metal most likely to be satisfactory for producing a ductile high strength joint. The phase diagrams for the purpose of this survey were classified into two groups: 1—systems with large solubility in ß titanium, but negligible solubility in a titanium, and 2—systems with large solubility in a titanium. Those metals with melting points believed to be too high or too low for titanium brazing (Tim = 1730°C) were eliminated from consideration. The melting points of vanadium, tungsten, tantalum, hafnium, zirconium, and the platinum group are too high and those of zinc, lead, cadmium, and tin are too low. The remaining metals were grouped as follows: 1—large ß solubility: Cr,¹ Mn,² Fe;³ CO,4 Ni,5 Cu,6 Be,' Si." —large a solubility: Al.9

Jan 1, 1954

By Carl E. Williams

A computer program has been developed which will locate the economic limits of an open-pit mine and also designate which ore and waste blocks to remove per period (years or quarters) to maximize the discounted cash flow over the life of the mine. A set of operating constraints was carefully selected so that the following functions are controlled: (1) the removal of overburden by preproduction and production stripping exposes a fixed amount of ore; (2) a constant manpower and equipment usage is insured (except for trucks); (3) the tons of mill ore, concentrate, and stockpiled ore are regulated; (4) the number and extent of shovel moves are minimized; (5) the grindability of the rock is considered as well as the variable haulage cost caused by variable haulage distances and depths; and (6) the size of the shovel working area is regulated. As many as 50 alternate schedules can be produced per computer run. They are arranged in descending order starting with the best solution.

Jan 1, 1975

By H. F. Winham

The history, development, subsurface geology, production, economics and estimated reserves are discussed in this paper. The Magnolia structure is an anticline with a known maximum structural relief at 372 ft., and the areal extent of the producing acreage is 4494 acres. Production is obtained from the Smack-over oölitic lime and 116 successful wells have been drilled. The field, which was developed on 40-acre spacing, has been under strict control. It is believed to be producing with a strong water drive, To date it has produced more than eighteen million barrels and the estimate of ultimate recovery is 220 million barrels. Early History The Magnolia field is in colurnbia County, Arkansas, T. 17 s., R. 19 and 20 W. Various geologists had long been interested in this general area, and as early as 1921, John F. Magale was able to define a surface structure. The first wildcat, one of the first in Columbia County, was drilled in 1923 by Mid-States Oil Co., in sec. 10, T. 17 S., R. 20 W. This well was about 11/2 miles northwest of the Kerlyn oil Company's discovery well and was based on surface geological work done by Jewel and Dobie. Subsequently, several shallow wells that were not carried below the Upper Cretaceous beds were drilled in the immediate area of the discovery well, but none of them contained any commercial showings of oil Or gas. In the latter part of 1935, Elam and Magale (or Southwood) Garrett NO. I was located in sec. 13, T. 17 S., R. 20 W., 3/4 mile east of the discovery well. It was drilled to a total depth of 4018 ft. in the lowermost Glen Rose beds but failed to obtain any showings of oil or gas. Interest had been stimulated in this general area, however, by the discovery of several oil fields, mainly Glen Rose oil production in the Rodessa field in Louisiana in 1935, Smackover lime productioil in Snow Hill in May 1936, production from the Cotton Valley formation in Schuler in 1937, and Smackover lime production from the Buckner field in November 1937. With this background and subsequent seismic work, which was carried on partly because the old shallow wells drilled in the township had shown evidence of closure in the Upper Cretaceous beds, the discovery well, Kerlyn Oil Company's Barnett No. I, Sec. 14, T. 17 S., R. 20 W., was originally projected to a total depth of 6300 ft., to test the equivalents of the Morgan sands of the Cotton Valley series, then producing at Schuler. The well was carried to a depth of 6325 It. and tested the objective beds without finding commercial production. In the meantime, however, one well had found production in the Jones sand and another in the Smaclrover lime at Schuler. Kerlyn immediately made arrangements to deepen the Barnett well to the Smackover lime. The top of the Smackover lime was encountered at 7618 ft. and the well

Jan 1, 1943

By H. F. Winham

The history, development, subsurface geology, production, economics and estimated reserves are discussed in this paper. The Magnolia structure is an anticline with a known maximum structural relief at 372 ft., and the areal extent of the producing acreage is 4494 acres. Production is obtained from the Smack-over oölitic lime and 116 successful wells have been drilled. The field, which was developed on 40-acre spacing, has been under strict control. It is believed to be producing with a strong water drive, To date it has produced more than eighteen million barrels and the estimate of ultimate recovery is 220 million barrels. Early History The Magnolia field is in colurnbia County, Arkansas, T. 17 s., R. 19 and 20 W. Various geologists had long been interested in this general area, and as early as 1921, John F. Magale was able to define a surface structure. The first wildcat, one of the first in Columbia County, was drilled in 1923 by Mid-States Oil Co., in sec. 10, T. 17 S., R. 20 W. This well was about 11/2 miles northwest of the Kerlyn oil Company's discovery well and was based on surface geological work done by Jewel and Dobie. Subsequently, several shallow wells that were not carried below the Upper Cretaceous beds were drilled in the immediate area of the discovery well, but none of them contained any commercial showings of oil Or gas. In the latter part of 1935, Elam and Magale (or Southwood) Garrett NO. I was located in sec. 13, T. 17 S., R. 20 W., 3/4 mile east of the discovery well. It was drilled to a total depth of 4018 ft. in the lowermost Glen Rose beds but failed to obtain any showings of oil or gas. Interest had been stimulated in this general area, however, by the discovery of several oil fields, mainly Glen Rose oil production in the Rodessa field in Louisiana in 1935, Smackover lime productioil in Snow Hill in May 1936, production from the Cotton Valley formation in Schuler in 1937, and Smackover lime production from the Buckner field in November 1937. With this background and subsequent seismic work, which was carried on partly because the old shallow wells drilled in the township had shown evidence of closure in the Upper Cretaceous beds, the discovery well, Kerlyn Oil Company's Barnett No. I, Sec. 14, T. 17 S., R. 20 W., was originally projected to a total depth of 6300 ft., to test the equivalents of the Morgan sands of the Cotton Valley series, then producing at Schuler. The well was carried to a depth of 6325 It. and tested the objective beds without finding commercial production. In the meantime, however, one well had found production in the Jones sand and another in the Smaclrover lime at Schuler. Kerlyn immediately made arrangements to deepen the Barnett well to the Smackover lime. The top of the Smackover lime was encountered at 7618 ft. and the well

Jan 1, 1943

By H. F. Winham

THE history, development, subsurface geology, production, economics and estimated reserves are discussed in this paper. The Magnolia structure is an anticline with a known maximum structural relief at 372 ft., and the areal extent of the producing acreage is 4494 acres. Production is obtained from the Smackover oölitic lime and 116 successful wells have been drilled. The field, which was developed on 4o-acre spacing, has been under strict control. It is believed to be producing with a strong water drive. To date it has produced more than eighteen million barrels and the estimate of ultimate recovery is 220 million barrels. EARLY HISTORY The Magnolia field is in Columbia County, Arkansas, T. 17 S., R. 19 and 20 W. Various geologists had long been interested in this general area, and as early as 1921, John F. Magale was able to define a surface structure. The first wildcat, one of the first in Columbia County, was drilled in 1923 by Mid-States Oil Co., in sec. 10, T. 17 S., R. 20 W. This well was about 1 ½ miles northwest of the Kerlyn Oil Company's discovery well and was based on surface geological work done by jewel and Dobie. Subsequently, several shallow wells that were not carried below the Upper Cretaceous beds were drilled in the immediate area of the discovery well, but none of them contained any commercial showings of oil or gas. In the latter part of 1935, Elam and Magale (or Southwood) Garrett No. I was located in sec. 13, T. 17 S., R. 20 W., ¾ mile east of the discovery well. It was drilled to a total depth of 4018 ft. in the lowermost Glen Rose beds but failed to obtain any showings of oil or gas. Interest had been stimulated in this general area, however, by the discovery of several oil fields, mainly Glen Rose oil production in the Rodessa field in Louisiana in 1935, Smackover lime production in Snow Hill in May 1936, production from the Cotton Valley formation in Schuler in 1037, and Smackover lime production from the Buckner field in November 1937. With this background and subsequent seismic work, which was carried on partly because the old shallow wells drilled in the township had shown evidence of closure in the Upper Cretaceous beds, the discovery well, Kerlyn Oil Company's Barnett No. I, sec. 14, T. 17 S., R. 20 W., was originally projected to a total depth of 6300 ft., to test the equivalents of the Morgan sands of the Cotton Valley series, then producing at Schuler. The well was carried to a total depth of 6325 ft. and tested the objective beds without finding commercial production. In the meantime, however, one well had found production in the Jones sand and another in the Smackover lime at Schuler. Kerlyn immediately made arrangements to deepen the Barnett well to the Smackover lime. The top of the Smackover lime was encountered at 7618 ft. and the well was cored and drilled to a depth of 7740 ft.

Jan 1, 1942

By I. P. Pardee

In our mixture at Musconetcong Iron Works we have an exceedingly hard, dense, magnetic ore, which contains some iron pyrites. The sulphur runs from 0.5 to 1.5 per cent. To prepare this ore better for the furnace, and with a view of making a softer iron, we tried roasting the ore in a Gjers kiln. When it worked well, the improvement in the iron was very perceptible ; but the ore was continually sintering and forming scaffolds across the bosh of the kiln.

Jan 1, 1887

By I. N. Knap

Discussion of the paper of HOWARD R. HUGHES, presented at the Now York meeting, February, 1915, and printed in Bulletin No. 99, March, 1915, pp. 629 to 635. I. N. KNAPP, Ardmore, Pa.-The claims made in the paper for the Sharp & Hughes cone bit are modest. I have used it with satisfactory results. It is a wonder for eating through hard, brittle rock; it will drill through iron pyrites that the fish-tail bit cannot enter. Soft ground is apt to contain concretions that are much harder than the containing ground. ?We have at times in drilling with a fish-tail bit thought the hole was partly in such hard material and partly in soft, thus making a difficult place to drill past in the ordinary way. By changing to a Sharp & Hughes cone bit such obstructions were easily overcome. This cone bit has greatly widened the range of work that may now be profitably accomplished by the hydraulic rotary method of drilling. It is not, however, adapted to drill soft or sticky ground, the old fish-tail bit being better for such purposes. The fish-tail bit usually scrapes its way through the material drilled, but not always. I believe at times it cuts and chips in soft friable rock. That is, the bit seems to bite into the rock, and when sufficient torsion is put on the drill stem it breaks its hold and jumps around and chips the rock from the bottom of the hole, like a stone cutter's chisel, and then takes another hold. This condition occurs only in friable material when the bit is sharp and the feed properly controlled. The Sharp & Hughes cone bit is a most valuable -tool for the rotary driller.

Jan 5, 1915

By E. A. Hopkin

Laboratory tests conducted by the author. together with actual field experience in Canada. have indicated the magnitudc of some of the factors affecting ability of drilling mud to clean the hole. A correlation was observed between funnel viscosity and particle slip velocity. A relationship was also observed between the Bingham yield value of the mud and the particle .slip velocity. Laburatury tests indicated little change in slip velocity with funnel viscosities up to ahout 80 sec/qt or to yield values of aboul 15 lb/100 .sq ft. The lip velocity of the partic1e.s. studied vuried from 160 ft/min with water to neerly zero for high mud viscositie. lncreasing the mud density, creating laminar annular mud flow or rotating the drill pipe Mlay also improve the carrying capacity of mud. Field tests indicated that during fast upper-hole drilling, the rate of cutting removal must he sufficien to maintain the concentration of cuttings in the annulus at less than 5 percent by volume to prevernt balled-up drill collars and .stuck drill pipe. INTRODUCTION In the Mid-Continent area, hole cleaning during rotary drilling normally involves the use of low-density drilling muds with funnel viscosities varying from 26 to 80 sec/qt. However, frequently it is necessary to raise the mud viscosity in excess of 200 sec/qt to clean the hole. In addition, field experience has indicated that during very fast upper-hole drilling, annular mud velocities considerably in excess of the maximum slip velocity of the cuttings (normally considered to be 120 to 150 ft/min) are necessary to prevent balling the bit and drill collars. In view of these variations in mud properties and circulation rates necessary to clean the wellbore, a study of factors affecting hole cleaning and the relative magnitude of each was undertaken. The study was also prompted by the knowledge that a drilling mud with properties close to those of water would drill at rates several times that of a viscous mud. The carrying capacity of these near-water muds was not clearly understood, however, and many drillers were reluctant to use them. DISCUSSION EFFECT OF MUD PROPERTIES ON DRILLING RATE The effect of mud properties on drilling rate has been studied by a number of investigators. 1t is clear from their work that mud properties close to those of water will significantly improve drilling rate and bit life. If the water-type mud will also effectively clean the hole and cause no logging or formation impairment problems, the choice of an appropriate drilling fluid is clear—use water. Often, however, a water-type drilling fluid is not capable of effectively cleaning the hole. THEORY OF PARTICLE SETTLING The forces acting on a particle that is allowed to settle through a fluid quickly reach equilibrium, and the particle settles at some constant velocity referred to as the slip velocity. The slip velocity of any particle depends upon a number of factors such as density and viscosity of the fluid, the volume, specific gravity, shape and roughness of the particle, and upon the shape and area of the projected face of the particle at right angles to the direction of relative fluid solid movement. Brown' expressed this relationship for spheres in Newtonian fluids in the following equation. where v, = slip velocity D, — diameter of sphere p, = density of spheye p, = density of liquid /a = friction factor g = constant. The friction factor f, varies as the size, shape, surface roughness and slip velocity of the body, and as the density and viscosity of the fluid varies. WaddelV ound experimentally that where dynamic similarity exists. f, was a function of the particle Reynolds number (NRe) of the sphere (Fig. 1). Fig. 1 shows that f, for spheres varies from over 10 for low NKe numbers to 0.44 for N,,. over 600.

By R. W. Armstrong, D. H. Feisel

Self-diffusion in pure crystalline solids has been described through extension of the Cohen and Tum-hull volume -fluctuation model originally proposed for diffusion in simple liquids. It is shown, for a number of crystalline solids, that the self-diffusion coefficient, D, obeys the relationship where a is the lattice spacing, v the Debye frequency, Z' the lattice-volume fluctuation per atom required for a diffusion jump, and (?V/Vo) the relative increase in the lattice volume resulting from thermal expansion between O°K and the temperature under consideration. The calculated value of Z' is dependent upon the difiusion mechanism and the lattice geometry. ThE need for an increased understanding of mass-transport processes in crystalline solids has resulted in much research to determine rates of self-diffusion.' For several metals (e.g., copper, silver, and iron), the experimental values of the self-diffusion coefficient, D, have been determined over a large interval of temperature and the accuracy of D has been investigated through repeated experiments. Also, a number of empirical and theoretical diffusion studies have established a rational basis for understanding the D values for the different elements.2"6 The empirical diffusion analysis by Sherby and simnad6 supplied the main stimulus for the present study. Sherby and Simnad, reviewing the self-diffusion data for a substantial number of pure crystalline solids, suggested that sufficient data were available to establish with some certainty the apparent intrinsic material properties which influence D. Without explicit regard for any mechanism of diffusion, these investigators obtained an empirical relationship for D which correlated the self- diffusion coefficient for each element with the melting temperature, crystal structure, and valence of the particular element. Their analysis is only unsatisfactory in that the effect on D of crystal structure is not very clear and the valence to be assigned to an element is not always straightforward. The present study is an attempt, from a very different viewpoint from that of Sherby and Simnad, to establish a basis for understanding the self-diffusion coefficients for crystalline solids. This analysis was undertaken for the purpose of developing a general expression for D which would explicitly depend on the mechanism of diffusion. The main result of the study is that diffusion in crystalline solids may be described in terms of a volume-fluctuation model which was originally proposed by Cohen and Turnbull7 to describe diffusion in simple liquids. The model appears to be useful for predicting self-diffusion coefficients in crystals. The following sections describe the volume-fluctuation model for diffusion, the application of this model to crystals, and the resultant agreement with experimental data. 1) THE VOLUME-FLUCTUATION MODEL FOR DIFFUSION Cohen and Turnbull7'8 developed their model for liquid self-diffusivity for the purpose of describing certain properties of liquids, glasses, and the liquid-glass transition. A hard-sphere model for the liquid structure is used. In this model, the size of a spherical molecule or atom is fixed for all temperatures by the interatomic spacing at the absolute zero of temperature. At any temperature above O°K, the atom is viewed as being contained within a larger spherical cage defined by the interatomic spacing of the atoms at that temperature. A random distribution of varying cage sizes is assumed to exist in the liquid. An individual diffusion jump occurs when the free volume of an atom (the volume of the cage containing the atom minus the volume of the atom) is large enough for the atom to jump out of its cage. With this physical picture of diffusion in liquids, Cohen and Turnbull derive the following equation for self-diffusivity: D=Doe-yv*/vf [1] where Do is the product of three factors which are the diffusion-path geometry, the diffusion-jump distance, and the velocity of the diffusing atom, v*

Jan 1, 1964

By S. I. Liu

THE effects of strain histories, consisting of several prestrains in opposite directions, on the flow and fracturing characteristics of metals determined in a final test have been investigated previously.'" Such strain histories vary from a single prestrain in tension or compression to the number of strain cycles leading to fatigue failure.' Between these two limits, various strain histories could be visualized and some can be attained readily. One such example is a strain history consisting of a first prestrain in tension of various magnitudes and a second prestrain in compression also of various mag-nitude. In this investigation the strain history was extended to the combination of these two limits, i.e., a single prestrain in tension or compression followed by balanced strain cycles of a selected magnitude e, = k0.12. It was found in this case that only compressive initial prestrains could be investigated with sufficient accuracy.* Such strain histories can be considered also as (low cycle) fatigue tests of a metal subjected to various amounts of cold working. It appears from previous publications that cold working within a wide range of reductions usually raises the un-notched fatigue strength of many metals.'-' This effect, however, has been found to be inconsistent and sometimes reversed for other metals?.7 Furthermore, Ludwik reports that the yield strength of cold-worked specimens may be reduced by cyclic strains, while that of materials without cold work is generally increased in the initial cycles." " In addition to the above tests, a study was made of the effect of intermediate re-solution heat treatment on low cycle fatigue behavior. Such anneals should eliminate the strain hardening induced by the cyclic strains. As far as their effect on the fracture characteristics is concerned, a few previous tests seemed to indicate that the damage resulting from cyclic strains is retained only partially after heat treatment." A further investigation was made in which one specimen was subjected to repeated unbalanced tension cycles in which the strain interval was approximately $ 0.013. This repetition of plastic tension damages the material slightly. This result appears to confirm Ludwik's observations." " Commercial 3/4-in. rod of the aluminum alloy 24ST4 was selected for this investigation. The material was subjected to the following treatments before machining: 1—Re-solution treatment at 920" ± 10°F for 45 min, 2—water quench at room temperature, and 3—aging for four days at room tem-perature.? The treated material then was machined to desired specimen contour and tested. A coolant was used during machining to minimize any artificial aging effects of heating during machining. In some cases the 24ST4 specimens were reheat treated after having been strained. In these cases, the heat treatment was the same as the re-solution heat treatment described above. Procedure As shown in Fig. 1, threaded end specimens with a minimum diameter of 0.266 in. and a contour radius of 2 in. were used for prestraining to an axial compressive strain ranging from 6, = —0.10 to E, = —0.48. For large prestrains, two consecutive corn-

Jan 1, 1952

By Milton E. Wadsworth, J. Brent Hiskey

Galvanic interaction between particulate chalcopyrite (CuFeS2) and copper results in the rapid conversion of chalcopyrite to chalcocite. The effects of temperature, surface area, concentration of sulfuric acid and agitation were systematically evaluated. The kinetics were found to be controlled by a steady-state current flow controlled by the effective anodic and cathodic surface areas involved in the galvanic couple. The experimental activation energy was 11.5 and stoichiometric data and reaction products have been characterized. The overall kinetic system has been evaluated based upon an electrochemical model.

Jan 1, 1974

By R. J. Lloyd

INTRODUCTION The Mount Isa Mine is a large modern underground mine located in North-Western Queensland, Australia. Two ore types are mined and treated separately. Currently silver-lead-zinc ore is mined at the rate of 2.6 million tonnes per annum and copper ore at the rate of 4.6 million tonnes per annum. The silver-lead-zinc orebodies are mined by sub level open stoping and cut and fill methods whilst all copper ore is extracted by various forms of sub level open stoping. The mining operations are highly mechanised and utilise diesel powered load-haul-dump units of various sizes, two and three boom face drilling jumbos, electric-hydraulic rotary-percussive ring drills, in-the-hole hammer drills, rotary blasthole drills, raiseborers, battery/trolley locomotives, a large fleet of rubber tyred service and supply vehicles plus light rockdrills mounted on airlegs, rail mounted overshot shovels and battery and diesel powered locomotives. All stoping production ore is extracted with diesel powered load-haul-dump units. The ore is tipped into orepasses which connect to the main rail haulage levels. On the haulage levels electric battery/trolley locomotives are used to pull rakes of bottom dump or side dump trucks which feed the ore into primary crushers. Following two stage crushing the ore is conveyed to the shaft and hoistod to surface in bottom dump skips. Each ore stream has its own rail transport system, crushing stations and hoisting shaft feeding separate concentrators. This paper will consider some aspects of the role of equipment and machinery in the growth of the mine, will discuss in some detail the machinery and equipment in use today and will conclude with a look at some possible developments in mining equipment for the future, with particular reference to the Mount Isa Mine. A summary of mining equipment in use at Mount Isa is given in the Appendix. THE PAST Silver-lead-zinc ore was discovered at Mount Isa in 1923 and within a very short time many small mines were being developed. However the rich surface ore traces did not continue and by 1928 Mount Isa Mines Limited had acquired sufficient leases to plan for a large scale mine to exploit the low grade orebodies. At this early stage it was recognised that the mine would need to adopt the most mechanised mining techniques then available in order to overcome its twin disadvantages of low graaes and extreme remoteness. The Company introduced bar mounted drifters and overshot shovels to replace hammer and tap and hand shovelling in development work and by 1930 headings were advancing at the rate of 30 metres per week. In keeping with the concept of mechanisation the early engineers designed the Man and Supply shaft with a very large, for those days, cage compartment measuring 3.8 m x 3.4 m. This shaft was the main means of access into the mine for 36 years until the K57 shaft (now R62 shaft) was commissioned in 1966. Man and Supply is still in regular use. Production commenced in 1931 at an annual rate of approximately 660 000 tonnes of silver-lead-zinc ore. The mine was mechanised to an extent which was previously unknown in Australia; whilst the concentrator, smelter and power house utilised the most modern and efficient equipment available. Even so, the mine was very near to closure on several occasions and did not return a dividend to its shareholders for many years. Production levels remained at or slightly below 660 000 tonnes until a separate copper ore streani and mill was commissioned in 1953, doubling the existing production levels. The first underground crushers were installed at this time. Production rates expanded in the years between 1953 and 1973. By 1960 production reached 2740 000 tonnes of ore. In 1965-66 total production was 3650 000 tonnes and in 1973 the production rate plateaued at the current level.

Jan 1, 1981