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By Raymond D. Sloan

Dropping from third position among the oil-producing states of the nation in 1942, Oklahoma ranked fourth in 1943 with a total output of 121,431,ooo bbl., a decline of 11.9 per cent from the previous year's total of 137,792,000 bbl. Production ranged from a maximum of 346,900 bbl. daily in February to a low of 322,800 bbl. daily in October, and at the close of the year was averaging 330,000 bbl. daily from 52,096 wells, or an average of 6.3 bbl. per well. The state's well, average at the close of 1942 amounted to 6.7 bbl. At the turn of the year, it appeared reasonable to assume that Oklahoma's producing rate would continue its downward trend during 1944 unless reversed by greater than normal discoveries. To Jan. I, 1944, Oklahoma has produced 5,188,466,-ooo bbl. of crude oil. Development and Exploration A total of 1287 wells was drilled in 1943, representing an increase of 77 wells, or 6.4 per cent over the preceding year's total of 1210. Of the wells completed, 587 (45.6 per cent) were oil wells with an average initial production of 319 bbl.; 127 (9.9 per cent) were gas wells with an average initial of 8,639,000 cu. ft.; and 573 (44.5 per cent) were dry. A total of 333 wildcats was drilled (25.9 per cent of all wells), an increase of 13 (4.1 per cent) over the 1942 total of 320. Of the*wildcats drilled, 46 (13.8 per cent) were oil wells with an average initial production of 235 bbl.; 27 (8.1 per cent) were gas wells with an average initial of 8,249,-ooo cu. ft.; and 260 (78.1 per cent) were recorded as failures. Reconditioning of wells throughout the state led to a total recompletion of 230 wells. Of these, 131 were oil wells with a combined initial production of 8360 bbl., 31 were gas wells with a total initial of 211,950,000 cu. ft., and 68 were abandoned. The 46 successful wildcats opened 33 new producing areas, one of which produced from three separate horizons, and led to the development of production in new horizons in 11 old pools. While none of the 1943 discoveries have as yet developed into what might be termed major pools, the West Moore pool, in Cleveland County, and the West Edmond pool, in Oklahoma County, are the two outstanding new areas opened to production. The West Moore pool, sec. 29, 10 N., 3 W., discovered in December 1943, was completed for an initial production of 248 bbl. of oil in 3 hr. through small tubing chokes in the second Wilcox sand from 8787 to 8800 ft. One well was drilling in this area at the close of the year. The West Edmond pool, an April discovery in sec. 32, 14 N 4 W., is producing from the Hunton lime at a depth of approximately 6950 ft., the world's deepest Hunton lime pool. To the end of the year, 15 oil wells had been completed, with no gas wells and no failures. Accumulated production to Jan. I, 1944, amounted to 474,300 bbl. of 41" gravity oil. There were 29 active operations in the field at the end of the year. The West Edmond and West Moore pool discoveries established the first commercial production west of the Granite Ridge,

Jan 1, 1944

William M. Courtis, Detroit, Mich. (communication to the Secretary*):—I have a few items to add to the history of the Lake Valley mines. In December, 1879, I was sent to the Bassic mine of Colorado and then to Lone mountain, near Silver City, N. M., and to various copper-camps in Arizona. I staged from Glorietta, N. M., to Tucson, Ariz., stopping at Silver City to see the Cosette mine. This mine led to the opening of the Lake Valley mines, and is a deposit of similar formation. New Year's day, 1880, found me crossing the Rio Grande above the Jornado del Muerto. At Aleman, Victorio's band crossecl four hours ahead of us. We picked up four wounded soldiers to take to Fort Bayard, for during the day the colored troops under General Hatch had been driving the Indians back through the San Andreas mountains. The traveler of to-day little realizes the dangers of these trips, when over very rough roads we made about 100 miles in a day and a night. I subsequently made this trip six times, up to 1882, and each time I missed an Indian attack by from one to four days. The day I arrived at Silver City news had come of the massacre of 75 women and children at the San Francisco ranch. The fighting-men of' Silver City had gone to rescue others. I was the only passenger from Socorro, N. M., until we picked up the soldiers. The next day we came suddenly on 5 of Victorio's band, but we had picked up several miners, so our stage bristled with guns, and we mere let alone. At or near my stone quarry, 6 miles from Socorro, 9 men, were killed by the band that, a day or two after, killed George. Daly, Lieutenant White, and all their men. During this raid, our miners and women at the mine slept in the tunnel. At the Cosette mine I had 35 men at work. These Indian raids had

Jan 1, 1910

By J. H., R. W. Guard, Westbrook

In 1953 Kornilov and Mints' presented data on thermal expansion and electrical conductivity of the compound Ni3A1 which indicated the possibility of a transformation in Ni3A1 at about 600°C. The present paper gives results of some observations

Jan 1, 1960

By Alexander L. Field

The rate of elimination of carbon largely controls the time required to make a heat of steel by the basic open-hearth process and to an important degree determines the cost of refining. Practical experience has led to the generally accepted belief that the use of slags relatively high in iron oxide, such as are required to bring about rapid refining, leads to a certain sacrifice of quality in the product. As a consequence, a compromise must be made between the exceedingly slow rate of carbon drop which would correspond to the ideal case and the rapid rate which would best satisfy the condition of minimum cost. An increase in rate of refining necessarily implies an increase in the concentration of iron oxide dissolved in the metal. However, even for the infinitely slow rate that corresponds to slag-metal equilibrium, the metal would contain a certain definite concentration of dissolved iron oxide. It is a matter of great practical importance, therefore, to determine the quantitative relation between the minimum or equilibrium concentration of iron oxide in the metal and the higher concentrations which must actually obtain in practice. The present paper is devoted to the development of certain equations, derived from the established laws of physical chemistry, which will enable this relation between rate of refining and the degree of oxidation of the metal bath to be computed from operating data. So attempt is made to exhaust the possibilities of this general method of treatment. In considering rate of refining, attention is mainly confined to rate of carbon elimination. However, the equations are of a more general nature and their application may readily be extended. The results of the preliminary calculations given herein indicate that increased rate of refining may have a decided effect in increasing the concentration of iron oxide dissolved in the metal. The uncertainty which attaches to the calculated value for this relationship arises in part from probable errors in experimental data on which the calculations are based, and in part from the lack of complete or favorably disposed information on basic open-hearth practice. When the relation between rate of refining and degree of oxidation of the metal has been more accurately established than has been done in the present paper, it will then become possible to consider what comprises

By W. N. Poundstone, P. C. Thakur

Introduction Horizontal drilling in coal mines is a relatively new technology. The earliest recorded drilling in the United States was done in 1958 at the Humphrey mine of Consolidation Coal Co. for degasification of coal seams. Spindler and Poundstone experimented with vertical and horizontal holes for several years. They concluded in 1960 that horizontal drilling in advance of underground mining appeared to offer the most promising prospect (for degasification) but effective and extensive application would be dependent upon the ability to drill long holes, possibly 300 to 600 m, with reasonably precise directional control and within practical cost limits (Spindler and Poundstone, 1960). Mining Research Division of Conoco Inc., the parent company of Consolidation Coal Co., began a research program in the early 1970s to achieve the above objective. The technology needed to drill nearly 300 m in advance of working faces was developed by 1975 and experiments on advance degasification with such deep holes began in 1976. Preliminary results of this research have already been published (Thakur and Davis, 1977). To date nearly 4.5 km of horizontal holes have been drilled for advance degasification and earlier results were reconfirmed. In summary, these are: • The greatest impact of these boreholes was felt in the face area where methane concentrations were reduced to nearly 0.3% in course of two to three months from original values of nearly 0.95%. • The methane concentration in the section return reduced to 50% of its original value immediately after the boreholes were completed, indicating a capture ratio of 50%. • The total methane emission in the section (rib and face emission plus the borehole production) did not increase but rather gradually declined with time. • Initial production from 300 m deep boreholes in the Pittsburgh seam varied from 3 m3/min to 6 m3/min but then slowly declined as workings advanced inby of the drill site (well head) exposing a larger surface area parallel to the borehole. Encouraged by these results, it was decided to design a horizontal drilling system that would be mobile and compatible with other face equipment. A mobile horizontal drill can be divided into three subsystems: the drill rig, the drill bit guidance system, and borehole surveying instruments. The drill rig provides the thrust and torque necessary to drill 75- to 100-mm diam holes up to 600 m deep and contains the mud circulation and gas cuttings separation systems. The drill bit guidance system guides the bit up, down, left, or right as desired. Borehole surveying instruments measure the pitch, roll, and azimuth of the borehole assembly. Additionally, it also indicates the thickness of coal between the borehole and the roof or floor of the coal seam. Thus, it becomes a powerful tool for locating the presence of faults, clay veins, sand channels, and the thickness of coal seam in advance of mining. In recent years, many other potential uses of horizontal boreholes have come to light, such as in situ gasification, longwall blasting, improved auger mining, and oil and gas production from shallow deposits. The purpose of this paper is to describe the hardware and procedure for drilling deep horizontal holes. The Drilling Rig [Figures 1 and 2] show the two components of the mobile drilling rig: the drill unit and the auxiliary unit. The equipment (except for the chassis) was designed by Conoco Inc. and fabricated by J. H. Fletcher and Co. of Huntington, WV. The drill unit. It is mounted on a four-wheel drive chassis driven by two Staffa hydraulic motors with chains. The tires are 369 X 457 mm in size and provide a ground clearance of 305 mm. The prime mover is a 30-kw explosion-proof electric motor which is used only for tramming. Once the unit is Crammed to the drill site, electric power is disconnected and hydraulic power from the auxiliary unit is turned on. Four floor jacks are used to level the machine and raise the drill head to the desired level. Two 5-t telescopic hydraulic props, one on each side, anchor the drill unit to the roof. The drill unit houses the feed carriage, the drilling console, 300 m of 3-m-long NQ, drill rods, and the electric cable reel for instruments. The feed carriage is mounted more or less centrally, has a feed of 3.3 m, and can swing laterally by ± 17°. It can also sump forward by 1.2 m. The drill head has a "through" chuck such that drill pipes can be fed from the side or back end. General specifications of the feed carriage are: [ ] The auxiliary unit. The chassis for the auxiliary unit is identical to the drill unit but the prime movers are two 30-kW explosion proof electric motors. It is equipped with a methane detector- activated switch so that power will be cut off at a preset methane concentration in the air. No anchoring props are needed for this unit. The auxiliary unit houses the hydraulic power pack, the water (mud) circulating pump, control boxes for electric motors, a trailing cable spool, and a steel tank which serves for water storage and closed-loop separation of drill cuttings and gas.

Jan 1, 1981

By John B. Knaebel, Robert J. Grant

This paper outlines the trends in gold production since the discovery of America, in the world as a whole, and in the principal producing regions as well. World production climbed at an average rate of about 20,000,000 oz. per 5-year period until the record all-time output of 111,307,000 oz. in the period ending with 1915. Production fell off during the war period, but has been mounting since 1925, and will probably be nearly 100,000,000 oz. for the 5-year period ending in 1930. Total world production of gold from 1492 to the end of 1930, as closely as can be determined, is more than 1,061,000,000 fine ounces. More than one-half of this total, or about 575,000,000 oz., has been mined since 1900. In percentage of world production, the United States jumped from 4.8 per cent for the decade 1831-1840 to 44.5 per cent for the five years ending with 1855. This is the highest figure ever reached by this country, although, with the exception of the 10-year period ending 1865, it ranked first among the nationa from 1849 until the end of 1905. During the 5-year period ending with that year, the United States produced 24.7 per cent of the world's gold. The tremendous increase from South Africa following 1890 resulted in that country's becoming the largest contributor for the five years 1906-1910, a position it has held with increasing dominance ever since. Relegated to second place in the period 1906 to 1910, the United States produced nearly 20 per cent of the world's new gold until 1920. From 1921 to 1925 it averaged 13.6 per cent and since then it has continued to decline in relative importance, accounting for only 10.9 per cent in 1927. Final figures for 1930 may place Canada second among the gold producers of the world.

Jan 1, 1931

By H. M. Fisher, R. E. Snow, S. C. Sun

SEVERAL constructive and fundamental studies have been made in the analysis of data obtained from experiments carried on with batch ball and rod mills. The operating characteristics of ball milling in small continuous circuits have also been appraised. It is from these analyses that some of the theories of comminution have been developed. Relatively few studies of continuous rod milling have added significantly to the fundamental concepts, because seldom have they yielded sufficiently consistent results. Perhaps they have been too limited in their scope. Careful control of the variables in batch grinding is simple compared with that encountered in a continuous operation. This factor alone has discouraged many investigators. Occasionally results of systematic changes made in industrial rod mill circuits have been published, but usually the data are sketchy and are restricted because of the unwieldiness of the equipment used. The work, in general, has not been comprehensive; nevertheless it has provided empirical relationships that have bridged the gap between postulate and practice so that by proper manipulation of formulae, a mill designer can anticipate mill size and power requirements.14 Although operating variables of a small continuous mill are not so easy to control as with the batch mill, with present day devices, and with careful experimental work, consistent results can be obtained. Nearly four years ago, in the Process Laboratory, Allis-Chalmers Mfg. Co. began a systematic study of the effects of several variables upon the performance of the pilot rod mill. A mill was built in the laboratory to provide the versatility required for the proposed study. It was constructed in sections so that it could be operated, with a few modifications, as a rod mill 30 in. x 8 ft or 30 in. x 4 ft. The discharge end of the shell was flanged so that either an end peripheral discharge or an overflow discharge could be installed. Thus the performance of at least four types of mills could be studied merely by changing the type of discharge or the length of the mill shell. The grinding experiments were designed so that a study could be made of the way in which the mill speed, feed rate, and pulp density influenced the performance of both overflow and end peripheral discharge rod mills. Four sets of experimental data were collected from the four mill arrangements. The mill in each set of experiments was fed at four rates of feed depending on the length of the mill, at four pulp densities, and at five percentages of critical speed. Electrical and mechanical controls were in- stalled to regulate all these independent variables, and auxiliary devices were used to verify the precision of the controls at each point. The dependent variables used to quantify the experiments were the reduction ratio and the hew surface area produced as calculated from sieve analyses. These were incorporated with the energy factor by the calculation of both the new surface produced per unit of energy and the Bond work index.' Rod wear, as a dependent variable, was not studied because of the short period of operation for each run. Exclusive of repeat runs, each set of experiments yielded 80 products, and the total study at least 320 products, all of which were quantified. With the operating information collected, these data presented a bewildering accumulation. Statistical analysis has been invaluable in unraveling the confusion and in presenting a means of establishing the nature and the magnitude of the significant variables. Data presented in this paper are those from the 30 in. x 4 ft end peripheral discharge rod mill, Fig. 1, when limestone was ground at feed rates of 1000, 2000, 4000, and 5000 lb per hr, at pulp densities of 50, 60, 70, and 80 pct solids, and at mill speeds of 50, 60, 70, 80, and 90 pct of the critical speed. These 80 tests have all been run at least twice, and occasionally a third time, to prove that the data obtained were reproducible. The techniques of operation and the methods of quantification of results are described in the following pages and the results analyzed statistically to show the significant variables. The variables are plotted to show the relationships that exist. A massive dolomitic limestone from Waukesha Lime and Stone Co. was used for feed during these experiments because of its availability and its tex-tural uniformity. This limestone analyzed 28.7 pct CaO, 21.0 pct MgO, 6.0 pct SiO2, 0.4 pct A1²O³, and 0.3 pct Fe²O³ and had a loss on ignition of 44.1 pct. It had a rod mill grindability at 14 mesh of 9.6 grams per revolution from which a work index of 13.9 was calculated. The ball mill grindability at

Jan 1, 1955

By Warren J. Jackson, John L. P. Campbell

Automatic recording of the radioactivity of the earth's formations provides a log of relative intensities that, if properly interpreted, can be applied to oil-field engineering. Production, engineering, and geological departments regard the radioactivity log as a forward step in the securing of more conclusive information for successful well completions. Explanations of the technique, together with some of the problems to which radioactivity logging have been applied, are presented in this paper. Introduction Those responsible for the completion of new oil and gas wells, or with planning workover operations on old wells, have followed closely the development of radioactivity well logging because they are interested in reducing the number of unknowns that usually are present in such work. Many operators have made use of the log, or are acquainted with at least one of the applications, but it is unlikely that any one operator is familiar with all of the many applications that are possible. The purpose of this paper is to present a representative example of each of the many applications, wherever the information has been released by an operator, and to illustrate by hypothetical examples other applications, releases for which have not been given. In this way, it is hoped that a better understanding of the scope of this new engineering tool may be obtained. Athough the literature contains many references that describe in detail the theory, development, and application of radioactivity well logging, a brief discussion of the technique may be helpful to those who are investigating the subject for the first time, All rocks contain radioactive material in varying concentrations. In general, shales contain relatively more radioactive material than sandstones or limestones. These radioactive materials disintegrate with time into other materials of lower atomic weight, and in that process of disintegration the rocks are emitting many rays, the most penetrating of which is the gamma ray. The intensity of emission of the gamma ray is proportional to the quantities of radioactive materials present. A higher rate of emission would be observed, therefore, opposite a shale than opposite a sandstone or limestone. Since measurable intensities of gamma rays are capable of penetrating as many as five concentric strings of casing, and as the gamma-ray intensity is relative to the formations, the measurements of variations in gamma-ray intensities offer a means of identifying cased-off formations in their proper stratigraphic sequence. TEe Gamma-ray Curve The measurement of gamma-ray intensi ties is accomplished by means of an ioniza-tion chamber that consists of a heavy cylinder, about 3 ft. long, that contains two insulated electrodes and is Med with an inert gas under high pressure. Under normal conditions no current will flow through the gas when an electrical potential is set up between the electrodes, but when

Jan 1, 1946

By John L. P. Campbell, Warren J. Jackson

Automatic recording of the radioactivity of the earth's formations provides a log of relative intensities that, if properly interpreted, can be applied to oil-field engineering. Production, engineering, and geological departments regard the radioactivity log as a forward step in the securing of more conclusive information for successful well completions. Explanations of the technique, together with some of the problems to which radioactivity logging have been applied, are presented in this paper. Introduction Those responsible for the completion of new oil and gas wells, or with planning workover operations on old wells, have followed closely the development of radioactivity well logging because they are interested in reducing the number of unknowns that usually are present in such work. Many operators have made use of the log, or are acquainted with at least one of the applications, but it is unlikely that any one operator is familiar with all of the many applications that are possible. The purpose of this paper is to present a representative example of each of the many applications, wherever the information has been released by an operator, and to illustrate by hypothetical examples other applications, releases for which have not been given. In this way, it is hoped that a better understanding of the scope of this new engineering tool may be obtained. Athough the literature contains many references that describe in detail the theory, development, and application of radioactivity well logging, a brief discussion of the technique may be helpful to those who are investigating the subject for the first time, All rocks contain radioactive material in varying concentrations. In general, shales contain relatively more radioactive material than sandstones or limestones. These radioactive materials disintegrate with time into other materials of lower atomic weight, and in that process of disintegration the rocks are emitting many rays, the most penetrating of which is the gamma ray. The intensity of emission of the gamma ray is proportional to the quantities of radioactive materials present. A higher rate of emission would be observed, therefore, opposite a shale than opposite a sandstone or limestone. Since measurable intensities of gamma rays are capable of penetrating as many as five concentric strings of casing, and as the gamma-ray intensity is relative to the formations, the measurements of variations in gamma-ray intensities offer a means of identifying cased-off formations in their proper stratigraphic sequence. TEe Gamma-ray Curve The measurement of gamma-ray intensi ties is accomplished by means of an ioniza-tion chamber that consists of a heavy cylinder, about 3 ft. long, that contains two insulated electrodes and is Med with an inert gas under high pressure. Under normal conditions no current will flow through the gas when an electrical potential is set up between the electrodes, but when

Jan 1, 1946

By O. D. Gonzalez, R. A. Oriani

The migration of hydrogen and of deuterium dissolved in a iron and in nickel induced by an applied electrical potential has been measured over a range of temperature. In all cases the intevstitial solute migrates to the cathode. The deduced charges of transport are positive, independent of or slightly dependent on temperature, and markedly larger for the beavier mass. These results are interpreted as showing predominating momenlum transfer between electron holes and the acticated complex of the elementary diffusion act. THE migration of components of a metallic system under the action of an applied electrical potential is called electromigration or electratransport. This phenomenon has been known since 1861 and is becoming of increasing interest to metal scientists because of the opportunity it offers to explore the connections between mass transport and electron transport. Until recently, reliable data have been very scarce because of the difficulties inherent in the measurements. In addition, theoretical understanding has been either nonexistent or rudimentary and at present this situation is only moderately improved. Whereas the prevalent notion had been (and is still widely held) that electromigration directly reflects the state of ionization of a component in its equilibrium state in the metal, it is now becoming clear that the major, if not the sole, factor is the momentum transfer between the charge carriers, themselves in motion because of the applied field, and the metallic components in their activated state. It becomes important therefore to obtain reliable data over a range of temperature on electrornigration in systems where only one component moves, that is, either in pure metals (vacancy motion) or in interstitial solid solutions. Our choice of systems was dictated by our measurements' of the Soret effect in solid solutions of hydrogen and deuterium in iron and nickel. Indeed, the main reason for making measurements on electromigration at all is that we suspected a mechanistic connection between thermal diffusion and electromigration. In our former paper' we proposed that what is common to both phenomena is the momentum transfer between the charge carriers in the metal and the atom as it jumps from one equilibrium position to another. In Soret diffusion, however, there is in addition the dissipation of the energy of the jumping atom via pho-nons. We have since found that similar ideas for this interconnection have been developed by Fiks.2 In the present paper we will discuss in more detail our understanding of the mechanism of electromigration itself, but we turn first to a presentation of the experiments and results. EXPERIMENTS AND RESULTS Let us consider a metallic system in which only one component, m , can diffuse at the temperature in question, and to which are applied simultaneously an electrical potential gradient, grad cp, and a chemical potential gradient, grad p,. One may write3 for the material flux Jm and the electronic charge flux Je by applying the condition, grad = 0, to Eq. [I] and evaluating grad(um/T) for the isothermal case and for activity coefficient independent of composition over the relevant composition range. ere, c is the concentration and D the diffusivity of the mobile component. The experimental technique that we have used to measure Z* for the isotopes of hydrogen individually dissolved in each of two transition metals has been developed from a method used by Wagner and Heller.4 (A somewhat similar method was also used by Herold.5) A wire or thin rod of the metal under study connects two volumes of gaseous hydrogen at identical pressures; hence grad um = 0. A direct current is made to pass through the specimen, serving to maintain the specimen at the desired temperature and also to produce the electromigration of the hydrogen dissolved in the metal in equilibrium with the gaseous hydrogen. Under these conditions, the flux of hydrogen from one volume to the other is given, from Eq. [I] for grad( um/T) =0by

Jan 1, 1968

By David White

THE search for potash salts in the great "Red Beds? region of the Southwest, conducted for several years by the U. S. Geological Survey, the work being carried on for a part of the time in coöperation with the Bureau of Economic Geology and Technology of the University of Texas, has resulted in the discovery, within shafting depth, of potash salts, apparently of workable thickness and commercial quality, and prob-ably of great extent. Definite information is lacking as to the exact thickness of the potash beds, the size and boundaries of the areas underlain by workable strata, and the locations of the deposits richest and most favorably situated for exploitation. Briefly to review the salient features, of the general situation: We have in the great Red Beds region of the southwestern United States, embracing portions of central Kansas, western Oklahoma, eastern New Mexico, and northern and western Texas, .a series of sandstones. shales, anhydrite beds, clays and limestones, which; through an interval of 1000 ft., more or less, carry beds of salt, estimated by Darton1 to contain over 30,000 billions of tons of rock salt. It is the greatest known salt field of the world. At some points the intercalated beds of rock salt, one of which is reported by the driller to exceed 300 ft. in thickness, aggregate, accord-ing to the drillers' records, over 1000 ft. The sedi-mentary strata are similar in composition to those carrying the potash deposits of western Europe, and they were laid down at the same time and under condi-tions which, in many respects at least, were similar The stratigraphy and character of the beds are des-cribed by Darton2 and a, part of the area and the reported aggregate thicknesses of salt are shown, with some revision after Darton, in the accompanying map Fig. 1. The assumption that in the great areas of shallow evaporation basins spread over -the vast base-level region of saline deposition in the Southwest during Permo-Triassic time, potash salts were in some places, and at different stages, thrown down in crystalline deposits associated with the beds of rock salt, anhydrite, and gypsum, is, geologically speaking, more than reason-able. They are to be expected, and the conviction that they are probably present has long been held both in the Texas Bureau of Economic Geology and Tech-nology, under Dr. J. A. Udden, and in the- U. S. Geological Survey. Accordingly, for many years, efforts to determine whether potash deposits are present in this region have been made, though under very great difficulties, such as insufficient funds for boring, hack of drilling on private initiative in the more promising regions, hack of interest at first on the part of the drillers and companies, and, hater, inadequacy both of the methods of boring and of the sampling, to reveal in definite terms the thickness-of any saline stratum of given composition.

Jan 4, 1922

By E. H. Sellards

PHOSPHATE rock like most other mineral substances is found in nature in varying degrees of purity. Of the impurities that are present some are constituents of the rock itself; others are inclusions of a foreign substance within the rock; while still others represent merely associated materials or minerals, either clinging to the rock or found in cavities and natural depressions, and hence largely removed in mining. Some of these impurities are distinctly deleterious to the processes of manufacture for which the phosphate is mined, while others, although neutral in action or nearly so, yet by their presence reduce the average grade of the rock and thus acid useless bulk to the shipment. It is the object of refined processes of mining to bring the product, as delivered from the mine, to the highest possible grade consistent with the market requirements and demands. This, however, is not accom-plished without actual loss in the form of discarded phosphate. It is evident, therefore, that the devising of methods for reducing this loss in mining, and yet maintaining the grade of the rock which the market requires, is one of the serious problems that the producers have to face.

Jan 9, 1914

By L. Adler

Analysis of a mine roof can be based on fixed-end beam behavior. The author here analyzes the effects of zero restraint at deflecting beam supports. Formulae are given for determining permissible support deflections. Analysis of a mine roof in a bedded deposit usually follows the assumption that the behavior of the roof is analogous to a beam with both ends fixed. Yet it is recognized that the end restraint itself varies with the thickness of cover, so that at shallow depth the restraint is minimum, and at great depth, maximum.' Consequently, an analysis on the basis of fixed ends or full restraint represents only one extreme in the possible range of conditions. Since the actual amount of restraint is difficult to ascertain, a more rational approach is to consider the two extreme cases of end restraint. Such situations regarding uncertainty of the restraining effects of supports are not uncommon in structural analysis, and are handled in a like manner.' Since previous studies9)4 have dealt with full restraint, this paper will analyze the effects of zero restraint at deflecting beam supports. In such a case a mine roof with several intermediate supports becomes analogous to a uniformly loaded continuous beam on simple supports, as shown in Fig. 1A. Such a structure is statically indeterminate to a degree equal to the number of intermediate supports, n. Therefore, with the three equilibrium equations, n additional equations are needed. A number of methods exist to analyze this problem, but The Theorem of Three Moments is Simplest. The continuous beam is divided at each support into a sequence of simply supported single span beams, with the unknown end moments, as appears in Fig. 1B. Continuity requires that the common ends of adjacent beams have the same slope (Fig. 1C). eiB= B(i+l)~= ei(i+l)and MiB= Mti+I)A= Mi(i+i). [1I A Glossary of all terms is given in Table I. Furthermore, if we first consider that the supports do not deflect, the slope at a support is the sum of the slopes due to each of the individual loads shown in Fig. 2, yielding:

Jan 1, 1961

By P. A. E. Armstrong

For hardening, the steel should be heated just above the critical temperature, as a properly forged steel quenched from this heat has some toughness, with maximum hardness and density. The quenching bath should be kept at approximately a constant temperature. In drawing or tempering, longer time periods at lower temperatures are better than the shorter periods at higher temperatures. A recent questionnaire brought out the following facts: The double-arc, double-taper bit and cross bit give the best service; resharpening of the drill steels most frequently was caused by wear of gage; chipping of bit was, with one exception, the second cause; breakage of shank was with one exception, the third cause; upsetting of bit, upsetting of shank, and breakage of body were the fourth cause. The direct cause of the necessity of resharpening given was poor heat treatment first, and faulty steel and severe rock conditions second. Rock-drill Steel By N. B. Hoffman Much of the drill steel produced in America is manufactured into hollow rods. After all forging has been finished the entire bar should be thoroughly annealed and heat trcated before the point is hardened and tempered, at least where the drill has heavy duty, such as working in deep holes and hard rock. A large number of tools of like character and doing work requiring similar properties are now being made of alloy steels; for instance a steel with a carbon content of 0.75 to 0.85 per cent., manganese 0.25 to 0.35, phosphorus under 0.020, sulfur under 0.030 and vanadium 0.18 to 0.23 has proved very satisfactory for chisels. A steel of this type properly manufactured will be far superior to the ordinary carbon steels, while at the same time is one whose price range should not prove prohibitive. Much of the cutting efficiency of a drill depends on proper heat treatment. This vanadium steel has a far greater safe hardening and forging range than ordinary carbon steels, making it more nearly foolproof. It will harden nicely at 1400" I?. but will also harden well and satisfactorily at 1550" F. retaining its quality of hardness and toughness in either case. Drill Steel from Hollow Ingots BY P. A. E. ARmstrong Hollow drill steel is made from a drilled billet with a sand-filled core or the drilled, pierced, or the drilled and pierced billet, not sand-filled, is rolled down over a projectile or ball much the same as in ordinary pipe manufacture. The first is the method generally used in this country; the second is used largely in Sweden. Swedish hollow drill steel has a

Jan 1, 1922

By R. H. Wightman, G. H. Adams

In order to secure good results in the prevention of accidents, it is generally recognized that the desire for such accomplishment, as well as the aggressive and constructive action to achieve it, must emanate from the Top Management and permeate successively down through the "Chart of Authority" to the workmen. Several years ago, with the above as a basis and with full support of the Top Management, the Mining Department started a program of selling the foremen and bosses the idea that safety could be achieved and that it was desired and required. Using psychology, persistence and numerous other methods, the foremen and bosses were finally impressed with the idea that "It can be done" and "It will be done." With this in mind, new ideas were brought forth by the foremen and bosses regarding the caving operation and the specific jobs in the operation. These new ideas were taken up in round-table discussions and resulted in certain changes in the undercutting method and the actual drawing of the blocks. These changes resulted in increasing fragmentation of the blocks which prevented the usual hang-up areas in the blocks. With the rock smaller in size and within reasonable reach from the tapping drifts, accidents were prevented in the tapping section. At the same time, an enforced campaign of housekeeping throughout the mine was undertaken with very beneficial results. The foremen and bosses then, in turn, educated and trained the workers themselves to become safety conscious. In so doing, a constant reminder was given on all jobs assigned that the job was to be done safely as well as efficiently. No man is assigned a job who is not qualified for the type of work required. Efficiency and safety go hand in hand. Safety Rules To supplement and aid this safety conscious attitude, certain safety rules applicable to our operation, a modified block caving system of mining limestone, in addition to the established state regulations, were put into effect and enforced. The specific rules referred to above and which will be mentioned below are in most cases simply a means of applying and complying with the very adequate "Mine Safety Orders" issued by the Industrial Accident Commission of the State of California. Some of the safety rules and policies are as follows: All men are required to wear safety

Jan 1, 1950

By K. R. Y. Simha

Successful explosive gas well stimulation requires a thorough understanding of explosively driven cracks under confining in-situ stresses. In a previous paper (Simha, et a1 1983) the problem of explosively driven cracks was experimentally investigated to reveal the features of crack propagation. It was observed that the explosively driven crack propagation is the result of two different but overlapping phases. The first phase involving the initiation and early time crack propagation is entirely governed by the explosively generated stress transients. The rapidly decaying stress transients then lead to the second phase of crack propagation largely controlled by the in-situ stresses. The purpose of this paper is to more fully understand the characteristics of the first phase concerning the initiation and early time propagation of explosively driven cracks. Experiments are conducted with plastic models under biaxial compression and the dynamic event is observed with a high speed multiple spark gap camera of the Cranz-Schardin type. The experimental observations are utilized to propose analytical models of crack initiation under explosive loading to aid in the design of multiple fracturing necessary for successful application of modern well stimulation techniques.

Jan 1, 1984

By F. V. Lenel, G. S. Ansell

The creep behavior of an aluminum -aluminum oxide alloy, A T 400, fabricated by compacting an atomized aluminum powder, extruding the compact, cold working, and recrystallizing the extrusion, was investigated. This alloy has a dispersion spacing of 1 . Previously Ansell and Weertman determined the steady-state creep rate of a recrystallized aluminum-aluminum oxide SAP-type alloy, MD 2100, with a 0.48-p dispersion. This alloy was found to have a steady-state creep rate of less than 10-6 min-1, too small to be measured accurately. By employing a more sensitive method of measuring creep rate, it was possible to determine the steady-state creep rate of AT 400 alloy, which is somewhat faster than that of MD 2100, at a series of temperature and applied stresses. Above a stress of Burger's vector, A = dispersion spacing, u = is a shear modulus) the rate follms an equation of the type: Steady-state creep rate K = A exp. where A is a constant, Q is the activation energy for sey-diffusion, and is the applied stress. At stresses lower than the steady-state creep rate drops off sharply and is no longer in agreement with this equation. This behavior is in good agreement with that predicted by the model for dispersion strengthened alloys in the stress and temperature range investigated. The absolute value of the creep rate is, however, four orders of magnitude lower than that predicted if the normal number of active dislocation sources are assumed to be present. It is concluded that in this SAP-type alloy the usual three-dimensional dislocation network is not present. Instead, short dislocation segments extending from one dispersed particle and terminating at a neighboring particle may act as dislocation sources. With this provision the creep model proposed by Ansell and Weertman reasonably accounts for the creep behavior which was observed. RECENTLY, Ansell and Weertman1 proposed a dislocation model from which they derived creep equations to describe the steady-state creep behavior of dispersion - strengthened alloys. Following Schoeck,2 they assumed that the rate controlling process for steady-state creep is the climb of dislocations over the dispersed particles. In order to verify their creep model, Ansell and Weertman determined the steady-state creep behavior of an aluminum-aluminum oxide SAP-type alloy, MD-2100, in both the fine-grained as-extruded, and coarse-grained recrystallized conditions. Since the grain size was the order of the dispersion-spacing, their model was not applicable for the as-ex- truded alloy. It should, however, be applicable to the coarse-grained recrystallized alloy. The results they obtained were rather unexpected. No meas-ureable steady-state creep was observed for the recrystallized MD-2100 alloy. If their model is correct, and if the second-phase particles act solely to hinder dislocation motion, then some measureable steady-state creep would have been expected. On this basis, they postulated that, in this SAP-type alloy, the main effect of the fine dispersion was to inactivate dislocation sources rather than to hinder the movement of dislocations. In order to understand more fully this unusual creep behavior, and to determine the validity of the model proposed,' the steady-state creep behavior of an aluminum-aluminum oxide recrystallized SAP-type alloy, with a somewhat coarser dispersion spacing, was investigated. The results of this study are presented in this paper.

Jan 1, 1962

By P. E. Cavanagh

SINCE the 1930's' the production of iron ore in Canada has increased from zero to about 15 million tons per year. In the same short period of about 25 years, the steel industry has doubled in output, while the consumption of steel has also doubled. In the 1930's all Canadian steel was made from imported iron ore, whereas today, Canada is exporting considerably more iron ore than she imports. It appears certain that the production of iron ore in Canada will at least double in the near future, and should be over 45 million tons per year at the end of the next 25 years, in 1980. It also appears certain that most of this iron ore will be exported to the United States, with some proportion going to Europe. In this situation, it is logical and proper at the present time for Canadians to consider means of converting some of all of this Canadian iron ore into semi-finished or finished products in Canada.

Jan 6, 1958

By L. B. Underwood, C. J. Distefano

NORAD, when completed, will be housed in large chambers excavated out of the granite beneath the Cheyenne Mountain near Colorado Springs. A room and pillar layout for the chamber excavation was selected and executed. Many complex problems arose in designing a rock bolt system; this paper includes discussions on: rock strengthening following excavation, excavation and ground support problems, orienting rock bolts with respect to jointing systems, conducting pull tests, four-way chamber intersection problems, the need for grouting rock bolts, and loss of tension and permanency of anchorage in a rock bolt system. In the event of a sudden nuclear attack upon the United States, it is imperative that vital command and control centers have a high probability of survival. One such vital facility is the North American Air Defense Command Combat Operations Center at Colorado Springs, Colo. Known briefly as NORAD, this installation when completed will be housed in large chambers excavated out of granite beneath the eastern slope of Cheyenne Mountain (Fig. 1). The NORAD COC, a U.S. Air Force sponsored project, will serve as the primary collection and evaluation center for data concerning unknown aircraft, missiles, or space vehicles, which might bring destruction to North America. The data will be fed into high-speed computers and electronic equipment from outpost sources: radar, ballistic missile early warning stations and picket ships throughout the world. Electronically controlled display boards will make it possible to evaluate the tracking data instantaneously and to take appropriate defensive action.'

Jan 1, 1968

By P. R. Sahm, T. V. Pruss

Mixtures of fine GaSb and Gds as well as preal-loyed GaSbl,As, powders were hot-pressed at 690°C and 25,000 psi. Dense alloys with compositional gradients of less than 5 pct were obtained from mixtures containing about 20 mol pct GaAs. For x < 0.2, there were increasing compositional gradients, and for x > 0.2 a GaAs-rich second phase appeared in the microstructure. Densification as well as alloying wlechanisms were enhanced by dissociation and, possibly, oxidation reactions of the powders. Densification of coarse prealloyed material, however, primarily depended on plastic flow phenomena and required temperatures just below solidus and pressures of 50,000 psi Thermal and electrical properties were measured. Although in no case was the figure of merit of melt growth materials approached closer than to within 25 pct, the better overall thermoelectric properties were found in coarse-grained, prealloyed materzals which had been compacted to near theoretical density and where grain regrowth had been induced. Similar results are believed to hold in other binary 111-V compound systems if processed under similar conditions. The densification of unalloyed GaSb powders during pressure sintering (= hot pressing) was shown to depend strongly on powder particle size.&apos; Fine powders displayed a "liquid skin effect" that enhanced compaction through the presence of liquid gallium, whereas coarse powders compacted predominantly by plastic flow. The liquid skin effect, in particular, appeared attractive for alloying GaSb with other, higher-melting, III-V compounds, and to densify these in a one-step operation. This is of special interest in the case of III-V compound alloys as the conventional techniques of melt growth or long-time annealing of powders2 is very time-consuming, especially in cases where a large separation of liquidus and solidus can be expected, such as in GaSbl alloys.2 It was felt that experimentation with this system, a particularly unfavorable example, would allow us to extrapolate to several other, more favorable, cases. Uses of Ill-V alloys are most evident in thermoelectric energy conversion devices.&apos; For this reason certain thermal and electrical properties were measured and compared to those of melt-grown material and to hot-pressed prealloyed powders. EXPERIMENTAL PROCEDURE The pressure-sintering apparatus has been previously described.&apos; Using this equipment, both powder mixtures of GaSb with GaAs and prealloyed GaSbl-,As, powders were hot-pressed. The mixtures were pre- pared from cast GaSb and melt-grown GaAs. The prealloyed material was obtained from stoichiometric melts, initially heated to 1200°C in an evacuated quartz ampoule, and then annealed in the solidus-liquidus interval. A typical annealing cycle consisted of a heating to 850°C (1 hr), extended successive annealing at 750°C (65 hr), and slow stepwise cooling (25 hr) to below solidus. The GaSb, GaAs, and GaSbl-,As, materials were ground in a vibrational mill to particle sizes below 500 . A jet mill reduced these further where necessary. Fine powders were analyzed by Coulter counting for their size distribution. Average sizes by volume were calculated from the data. Mixing of the powders, where necessary, was carried out through rapid vibrational motion. The hot-pressing operation consisted of a degassing period of 15 hr, in most cases at 690°C, followed by several hours of compression, normally 25,000 psi at 690°C for powder mixtures and 50,000 psi at 710°C for prealloyed powders. The chemical compositions were confirmed by X-ray fluorescence analysis. To estimate the degree of solid solution achieved, lattice parameters were determined and interpreted according to Vegard&apos;s rule. In addition, optical microscopy helped to correlate the relative amounts of the phases present as well as the degree of porosity to the measured density. To reveal grain boundaries, polished surfaces were etched4 with H 2 O:H 2 O:HCl = 2:l:l. In several cases microscopic concentration gradients were monitored by electron-probe analysis-. RESULTS AND DISCUSSION Alloying and Densification of GaSn-GaAs Powder Mixtures. After preliminary experiments showed that no appreciable alloying took place in mixtures of coarse GaSb (22.5 p) and fine GaAs (2.5 p) powders, hot pressing of mixtures was confined to fine powders only (3.1 and 2.4 p, respectively). Alloying and densification apparently occurred simultaneously with a grain regrowth mechanism which depended on the presence of a liquid phase.&apos; The liquid phase was provided by the dissociation of GasbS particles into liquid gallium and antimony above 555°C. This not only enhanced grain regrowth and densification, as in unalloyed GaSb,&apos; but took on additional importance here for the alloying process. Alloying was speeded up by the resulting liquid-solid interaction as compared to the very slow solid-state diffusion process normally expected at these temperatures.&apos; The results obtained with a series of powder mixtures have been compiled in Table I. It is seen that for mixtures with less than 20 mol pct GaAs, x < 0.2, the compositional ranges increased and for x > 0.2 a GaAs-rich phase and free antimony appeared in the microstructure in sizable amounts.

Jan 1, 1968