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By Jasper Stuckey

THE object of this paper is to record and interpret field and laboratory observations made by the writers during five years of study of the barite deposits of North Carolina. Deposits of barite are known to occur in three localities in North Carolina (Fig. 1) two of which-the Hot Springs and Kings Mountain -contain material of economic value. The Hot Springs area begins near Bluff, some 6 miles south of Hot Springs, and continues northeast by Stackhouse; a total length of 7 miles. The Kings Mountain deposits lie along a belt that extends from the north end of Crowders Mountain in a southwestward direction, along the east side of this and Kings Mountain, to Kings Creek, South Carolina. The third locality is 3 1/2 miles southeast of Hillsboro, Orange County, a short distance west of the highway leading from Hillsboro to Chapel Hill. It is not known when barite was first discovered in North Carolina, but production from the Hot Springs area began some 50 years ago. The state has never produced large quantities of barite-usually there have been less than three producers-and definite figures are not available, but reasonably reliable estimates indicate a total production of 300,000 tons. From 1901 through 1920 barite mining was on a seemingly prosperous basis and a large tonnage. was shipped from the Hot Springs and Kings Mountain areas. With the depression of 1920 the industry began to decline and production practically ceased in 1926.

Jan 1, 1933

By Kirtland Marsh

THE manufacture of gas masks by the Chemical Warfare Service, U. S. A., required preparation of the carbon used in the canisters. The largest plant for the production of this carbon was situated at the works of the Astoria Light, Heat and Power Co., at Astoria, N. Y.; this paper will deal1 with the pyrometry equipment at that plant. Commercial charcoal was found unsuitable for use in gas masks because of its low power of absorption and its poor resistance to abrasion. The best raw material for the production of carbon was found to be coconut shells, but any kind of nut shells or fruit pits were used when sufficient quantities of coconut shells could not be obtained. The shells were first carbonized in retorts, the carbon was then crushed and screened between 8 and 16 mesh, and finally submitted to a special heat-treatment in air; steam treatment was later substituted for treatment in air. The production of gas-mask carbon on a commercial scale was begun at Astoria about Aug. 1, 1917. Temperature control was essential during the initial carbonization of the shells, as well as during the air or steam treatment, and pyrometers were installed for this purpose. The installation and maintenance of all pyrometry equipment was done by the pyrometry department, consisting of an officer in charge, an assistant, and two men. A special pyrometry laboratory was maintained in which all repairs were made.

Jan 9, 1919

By R. Stefanko, Y. J. Wang, H. R. Hardy, R. Y. Kim

Since 1964, the Dept. of Mining at The Pennsylvania State University has been carrying out extensive studies associated with the phenomena of microseismic activity and inelastic behavior in geologic materials. Briefly, the program to date has involved the following stages 1) Study of the microseismic noise and energy rates for selected geologic materials under incremental, uniaxial tension.1,2 2) Investigation of the frequency spectra of microseismic activity of selected geologic materials under incremental, uniaxial tension.3,4 3) Investigation of the time-dependent inelastic deformation of geologic materials and the analysis of such deformation in terms of mechanical models.5, 6 4) Simultaneous study of microseismic activity and time-dependent inelastic deformation in geologic materials under incremental, uniaxial compression.7,8 Details of the research involved in stage 4 of the program constitute the subject of this chapter. It should be noted that the majority of the experimental data quoted in this chapter forms part of a thesis to be presented by one of the authors (Kim) in partial fulfillment of the requirements for the Ph.D. degree in mining engineering at The Pennsylvania State University. During the last two or three years, a number of important papers have been published which deal primarily with the fundamental structure and mechanical behavior of geologic materials. Recent papers 9,10 have provided research workers in the rock mechanics field with a meaningful overall picture of rock as a structural material. The concept that many

Jan 1, 1970

By William H. Kobbé

The word recovery as used in this paper is applied in its broader sense and not limited to wells producing from horizons of unconsolidated sands. Certain problems connected with the winning of petroleum from such horizons present themselves while drilling is in progress and should be considered before drilling is commenced wherever unconsolidated sands are expected. Maximum recovery depends not alone. upon efficient pumping methods but also upon the selection of a proper drilling system and the completion of a well especially adapted to the extraction of these oil-bearing sands. 11. DRILLING Determining Factors in Selection of Method The selection of a drilling method for the development of a region in which the oil reservoir consists of unconsolidated sands is based on the following considerations: (1) Character of the formations overlying the reservoir; (2) thickness of the oil-bearing stratum or strata; (3) thickness and character of water or gas sands; (4) gas pressure to be encountered or expected; (5) total depth of well. 1. Character of the Formations Overlying the Reservoir The strata overlying the reservoir may consist of beds of shales, clays, sands and other soft materials, or they may be slates, limestones and sandstones consolidated to all degrees of hardness. Very often the overlying strata are predominantly of soft materials but interbedded with harder formations. Likewise, soft strata are encountered at different horizons in an overburden consisting almost entirely of the harder sedimentaries. The physical character of this overburden is frequently

Jan 1, 1917

By A. G. McGregor

DURING the past 5 years, five new copper-smelting plants have been built and put into operation in the State of Arizona. The monthly copper output from these plants averages from 5,000,000 to 18,000,000 lb. Previously, there never was as much activity in copper-smelting plant construction in the same length of time in all the rest of the world. Naturally, in this amount of work, some new problems were met and new features in plant design and. equipment developed. Some of these features are described in this paper. CONCENTRATE HAULING, UNLOADING AND SAMPLING SYSTEM (a) Concentrate Car The International Smelting Co. has provided at its plant at Miami specially designed cars for hauling the concentrates from the mills of the Inspiration Copper Co. and the Miami Copper Co.. The car has a bottom that is readily made tight to hold flotation concentrates and is quickly and cheaply unloaded. Figs. 1, 2 and 3 show views and details of the car. The main feature of this car is the slot in the bottom throughout its length, which is closed by means of short planks that overlap like ship-lap as shown by Fig. 1. At one end of the car an iron gate operated by a screw and hand wheel is provided, which clamps or presses the planks together, making the bottom tight. A removable tapered plug rests vertically over this gate when the loading of the concentrates at the mill commences.

Jan 8, 1916

By J. L. Bray

IT is well known that iron markedly improves the physical properties and casting characteristics of aluminum bronzes. The use of 1 to 4 per cent iron as the principal modifying addition has become common practice in many foundries melting aluminum bronzes. Although the beneficial effects of iron are unquestioned, there is some uncertainty regarding the structural changes caused by it in the basic copper-alumi-num system. It is agreed that a new constituent appears in abundance when the iron content reaches 2 to 4 per cent. This constituent, which frequently occurs in shapes resembling clover leaves, is sometimes assumed to be an aluminum-iron intermetallic compound. If this were correct we might expect a change in the structural relationships of the matrix in the direction of decreased aluminum content. On the other hand, it has been reported that iron has a negligible effect in altering the fundamental relationships of copper-aluminum alloys1. Others2,3 have reported an additive coefficient. Apparently it will be necessary to know the equilibrium relationships between the phases of the copper-aluminum-iron alloy system to establish any such theory as fact. When this has been done it may very well be that a further revision in the structural relationships may be necessary to describe the changes to be expected in commercial cast alloys. It was with this latter problem before them that the authors attempted to

Jan 1, 1936

By W. F. Brace, James D. Byerlee

Although prediction of failure of rocks may be ultimately possible without knowing in detail how failure occurs, understanding of this process is certainly of fundamental interest in rock mechanics. Of the various failure mechanisms, probably brittle fracture is of greatest interest. Recent reviews have brought this subject nearly up to date (Hock,1 Price,2 and Jaeger 3) and here, we summarize certain recent developments. As our understanding of brittle fracture is derived almost solely from laboratory studies this will amount to a review of certain laboratory experiments. New studies in four areas are pertinent; these concern 1) the volume changes which accompany brittle fracture, 2) the propagation of cracks in compression, 3) certain frictional characteristics of rocks and minerals at high pressure, and 4) the law of effective stress for crystalline rocks. Our objective here is less to present an entirely consistent, complete picture of how a rock fractures than it is to emphasize gaps in our understanding and, thus, suggest areas that need further study. Progress is still painfully slow in this field and perhaps this approach will stimulate new work. OBSERVATIONS Although the behavior of large rock masses is most often the concern in rock mechanics, the number of large-scale experimental tests is still vanishingly small. Our experimental observations arc, by and large, still made on small, relatively flaw-free, rock samples. Here also we report the behavior of small samples.

Jan 1, 1967

By G. W. Elger, H. E. Bell, J. E. Tress, J. B. Wright

This paper describes laboratory techniques and subsequent results of US Bureau of Mines (USBM) research to produce chlorination-grade feed- stock from an abundant, low-grade, domestic, rock ilmenite ore. The research is part of the Bureau effort to devise technology that may help decrease US dependence on imported raw materials. A rock ilmenite containing about 46 wt % TiO2 was smelted in an electric arc furnace with coke, wood-chips, and Na2CO3 to separate most of the iron as pig iron and to form a low-iron, titanium-enriched slug. The slug was ground, pelletized, oxidized, and then sulfated with mixtures of SO2 and air in a continuous 4.5- to 9.1-kg/h (10- to 20-lb per hour) apparatus at 1023° to 122J0 K (1380° to 1740° F). The sulfated slug, containing 60% to 65% TiOb, was reground and leached in water at ambient temperature to decrease the combined levels of the troublesome calcium, magnesium, and manganese impurities from 7.0 to 1.7 wt 70. The final product was upgraded to about 8.4 wt % TiO2. This material is potentially suitable for chlorination in a fluidized bed reactor. The most favorable results were achieved with leached slug sulfated at a feed rate of 4.5 kg/h (10 lb per hour) and at temperatures of 1073° to 1123° K (1470° to 1560' F).

Jan 1, 1986

By Matti J. Saarivirta

Two new precipitation hardening copper-base alloys, Cu-1.5pct Ti-2.5 pct Sn and Cu-1.5 pct Ti-2.5 pct Sn-0.4 pct Cr were developed. High strength and medium conductivity are obtained by solution annealing and subsequent heat treatment. Combination of solution annealing, cold working, and heat treatment increases the strength further. Good elevated temperature strength and ductility makes these alloys superior to copper-beryllium-cobalt alloys. A considerable amount of research work is being done throughout the world to develop new and improved copper-base alloys. In many cases, the object is to develop alloys having a combination of high electrical and thermal conductivities, and high strength. The problem is complicated by the fact that any alloying element added to increase strength, invariably decreases conductivity. Among the few commercial precipitation hardening type copper-base alloys, the Cu-Be-Co alloys are best known. These alloys are used in many applications that require good spring characteristics cornbined with high strength and moderately high electrical conductivity. They can be formed readily after solution annealing, then heat treated to obtain high strength and conductivity. Because of the relatively high cost of the Cu-Be-Co alloys, considerable research has been aimed at developing new lower cost alloys having similar properties. As far as is known today, the binary Cu-Ti alloy is the only one whose properties are

Jan 1, 1962

By William E. Bonini, Eugene A. Hickok

IN the course of an investigation directed toward expanding ground-water facilities in Essex and Morris counties, New Jersey, the Board of Water Commissioners of the city of East Orange authorized a seismic-refraction survey1 for the purpose of delineating bedrock topography below unconsolidated overburden. Results of the survey were highly satisfactory and led to the preparation of a comparatively detailed bedrock contour map. Knowledge of the bedrock depth and configuration was an important aid in selection of sites for test drilling. The portion of the East Orange Water Reserve under consideration is in the flood plain of the Passaic River about 10 miles west of Newark, N. J. The flood plain is about 175 ft above mean sea level and is bordered by low hills rising to elevations of approximately 250 ft. The bedrock underlying the Water Reserve consists of sandstone and shale of the Triassic Brunswick formation and is covered everywhere by deposits of unconsolidated glacial outwash sand and gravel, lacustrine clay, and recent river silt as much as 150 ft thick. Yield of wells in the sandstone and shale averages 100 to 200 gpm. Since production wells constructed in the sand and gravel aquifer in the buried river valley shown on the contour map (Fig. 1) yield 300 to 1400 gpm, it was proposed to locate additional production wells in this buried valley, where the yields per well would be maximum.

Jan 4, 1958

By Joe L. Ratigan

INTRODUCTION Rock mechanics engineers are seldom concerned with obtaining the tensile or fracture strength of brittle rock at low mean stresses. The reason for this is two fold. Firstly, the behavior of many excavations in brittle rock is controlled by the inherent discontinuities in the rock mass. Because of the jointing and faulting, tensile strength is usually taken to be negligible. The second reason that tensile strength is seldom obtained in the laboratory is that the technology of utilizing this strength measure in design is undeveloped. Despite the fact that tensile strength of brittle rock is often ignored, there are a number of applications in rock mechanics wherein the knowledge of tensile strength is of fundamental importance. The apparent tensile strength must be known in a hydraulic fracture experiment if the state of in situ stress is to be determined from the initiation of the hydraulically induced fracture. In certain underground situations, the apparent tensile strength of intact rock beams defined by jointing or bedding planes is important in determining required rock bolting. Numerous other situations require a knowledge of apparent tensile strength including such high technology uses of underground space as geothermal energy extraction and LPG storage. Three observations are invariably made when intact rock samples are taken into the laboratory and tested to determine tensile strength. (1) The apparent tensile strength depends on the sample size (the 1 arger the specimen, the lower the tensile strength)

Jan 1, 1982

By A. Soundraraj, S. Singh, R. C. Deshpande

THE detonation of a high-explosive charge having a metal-lined conical cavity (shaped charge) results in a fast-moving jet and a slow-moving slug.1-4 Clark and Bruckner reported the metallographic studies of a cast-iron slug. The present note describes the metallographic studies of a copper slug and discusses the principle of flow involved. The shaped charge consisted of a 5-cm diam cylinder of cast high explosive (60-40 RDX-TNT mixture) having a 45 deg and 0.16-cm thick copper cone. The copper (99.5 pct purity) had a grain size of 0.06 to 0.08 mm diam and a hardness of 65 to 75 Hv. These were fired into a deep container of water and the slugs were recovered undamaged. The longitudinal and transverse sections of the slug were polished, etched, and examined for mi-crostructural changes. Macroexamination revealed a radial grain flow inwards towards the center and a downward component of flow towards the base of the slug. Fig. 1 shows schematically the micro-structural changes observed on the longitudinal section of the slug. The region D near the apex and also along the outer surface of the slug was characterized by the presence of heavily deformed and twinned grains. Some of the grains were having bent or crossed twins, Fig. 2. The grain size in this region was of the same order as that of the

Jan 1, 1960

PRESIDENT BENJAMIN B. THAYER,2 NEW YORK, N. Y. PAST PRESIDENTS JAMES F. KEMP,1 NEW YORK, N. Y. CHARLES F. RAND,2 NEW YORK, N. Y. FIRST VICE-PRESIDENT SIDNEY J. JENNINGS; NEW.-YORK, N. Y. TREASURER ' GEORGE C. STONE,1 .NEW YORK, N. Y. SECRETARY EMERITUS ROSSITER W. RAYMOND, NEW YORK, N. Y. SECRETARY BRADLEY STOUGHTON NEW YORK, N. Y.

Jan 8, 1914

By William E. Hubbard

During the last decade the known reserves of petroleum in the United States have increased from about five billion to over thirteen billion barrels. From the standpoint of public welfare the existence of these known reserves presents an undeniably favorable picture, but viewed from the position of many a harassed operator the blessing has not always been considered an unmixed one. Along with this increase in excess reserves, curtailment of production has come into being as a matter of necessity and the principle of proration as a matter of equity. As a practical matter it has been considered necessary to curtail the production of old wells as well as that of new wells in a pool. The right of new pools to produce has been recognized, and the allowable for them has come partly from increased market demand and largely from the allowables already enjoyed by the developed pools. The natural result—a downward trend in daily per-well allowables—has been especially felt by Texas operators. This trend may be illustrated by Table 1, which comprises the five active areas in Texas, and from which may be noted the following: 1. The average daily allowable per well has decreased about 53 per cent in three years. 2. Of the 184,000-bbl. increase in total allowable for the five areas, 29,000 bbl. came from the increase in state demand and 165,000 from the combined allowables of the remaining pools in the state.

Jan 1, 1937

By T. R. Cass, M. R. Achter

A technique for measuring the creep and rupture strength of nickel specimens bonded by sintered oxide layers has been developed for the investigation of the role of grain-boundary oxide in the oxidation strengthening of nickel during creep at 817 °C. Prom the inverse dependence of the rate of bonding on the thickness of the starting oxide, it is suggested that the rate of diffusion of Ni++ through NiO is the controlling process at the start of sintering. Cornparisons of the creep and rupture strength and of the microstructure of sintered couples with conventionul creep specimens suggest rupture in nickel is prevented by load-bearikzg, ikltergranular layers of oxide. A number of recent investigations have shown that at high temperature and low stress the creep-rupture strength of nickel and nickel-base alloys may be much greater in air than in an inert gas or vacuum.'-7 For example, at 817°C and 2500 psi, nickep failed in vacuum in 48 hr but not in air after 4000 hr, and a Ni-Cr-A1 alloy5 at 1038°C and 3000 psi failed in vacuum in 4 hr but not in air after 731 hr. Fig. 1 is a typical creep curve in air for materials experiencing this pronounced environmental strengthening. A common feature of these curves is the entry into a third stage of accelerating creep, concurrent with the for-

Jan 1, 1962

By Frederick Prime

In this second supplementary list no titles to which an * is pre fixed hare been seen by tlie compiler; and he will be most thankful to have any omiesisne or inaccuracies in the list sent to hiin to be ptiblisi~cd as a third supplement in the next volume of the actiotra. The author is indebted to Prof. J. J. Stevenson, of New Tork, Prof. P. R. Uhlcr and John 'CV. M. Lee, Esq., of Balti more, and Lloyd P. Smith, Esq., of Philadelphia, for valuable assistance. office, allkntorn iron compaxy, 30 South Third Street, Philadelphia, September 5th, 1881. Alabama. Geologiml Survcy of Alabama. report of Progress for 1879 and 1880, by Eugene A. Smith, State Geologist. Montgomery, 1881. 8vo., 158 pp., and 2 maps. California. Omit Report of Hon. T. Butler Ring, iu sopplemeut I. For Trask's Geology and Illdustrial honrecp, etc., in Supplenlvut I., read Tyson's, etc. Fremont's Menloir on Upper Califijrnia, is also published as XXXth Congress, lat Session. Senate Ms. Doc., No 148, and has a map. For Randall's Report in Supplement I, rend Report of the Special Committee in favor of a Geological Snrvey, subrn-itted by Mr. Randall, April 24th, 1861. n.d., 1851. 8cWo., 19 yp. XXXIst Congress, 1st Session, Sen. Ex. Doc., No. 47, Part 2 [Part 1 is Tyson's Report.) RejW of the Secretary of War in further compliance with the Resolution of the Senate?, calling for Colbies of

Jan 1, 1881

By V. Damiano, M. Herman

CELLULAR substructure observed in metal crystals grown from the melt. has been studied extensively'-' and is attributed to the existence of a constitutionally supercooled zone in the liquid ahead of the solidifying interface. The mathematical description of this process has been given in terms of the concentration of solute in the liquid phase, the rate of solidification, and the temperature gradien.t in the liquid as the only variables.5 This technical note presents some evidence of 1) the effect of crystal orientation on some aspects of cellular growth, and 2:) the degeneracy of these cells into dislocation arrays. The zinc single crystals used in these studies were alloyed with cadmium sufficient to produce the constitutional supercooled cellular substructure. Crystals containing 0.05 pct Cd exhibited substructure formation for a growth rate of 10 cm per hr and a temperature gradient of 15°C per cm in accord with the theory. The growing liquid-solid interface was examined after we liquid had been decanted away in a fashion similar to that described by Rutter and Chamers.' The cellular substructure was also observed after polishing and etching the surface directly behind the decanted interface with a solution of HNO, and water. Fig. 1 is a photomicrograph of a typical polished and etched surface revealing substructure, the cleavage plane, and twins. The crystal has been grown with its basal plane parallel to the direction of growth and the plane of the micrograph is per-

Jan 1, 1960

By Myron Rodgers

IN rock- or ore-crushing tests all data, in order to be valuable for study and comparison, should be obtained and tabulated under conditions as uniform as possible. The results of many such tests have no value for comparison, because of incomplete data and the lack of uniform conditions, screens and scale of sizing, etc. The purpose of this paper is to suggest a form of standard specifications which may be developed by the Milling Committee and approved by the A. I. M. E. for rock-crushing tests. It is not intended to discuss any theories of rock crushing. Reports of rock-crushing tests should include the following details: 1. Description of the machine employed (jaw or gyratory crushers, rolls, stamps, tube mills, Chilean mills, etc.). 2. Method and material (timber, concrete, etc.) of foundation. Much power is dissipated in the vibration of poor foundations. 3. Locality from which the rock or ore was obtained, and geological, mineralogical, and physical characters of the material. 4. The power consumption of the machine running with no load and with full load, the unit of power being 1 hp, per 24 hr. 5. The capacity of the machine in tons (of 2000 lb.) per 24 hr. 6. The duty in tons per horsepower-day. 7. The screen analysis of feed and product by the proposed A. I. M. E. standard screen scale. On the foregoing statement, the following remarks are offered.

Jan 9, 1915

By G. Barbery

Since the original paper, two methods have been introduced to compute the parameters of the three parameter size distribution equation: [ ] Both of them are based on graphical means, which are time-consuming and of little statistical significance. A program has been developed, using the Gauss-Newton method to compute by nonlinear regression analysis the parameters of the equation. Although the method is quite general in curve-fitting applications, it does not appear to be used in the field of size analysis, and a brief description is given. As applied here, the Gauss-Newton method involves the minimization of the least squares: [ ] where n is the number of sieves used. The second member of Eq. 2 can be approximated by a multiple Taylor's series expansion of first order about a starting value [ ] The minimization of Q (r,s,Xo) means: [ ] Putting Eq. 3 into Eq. 2 and differentiating, we obtain a system of equations which can be represented in matrix symbolism (box) The system can be solved for: [ ] and the operations repeated with new values: [ ] The starting values for r and s are taken as 1, for Xo, a value higher than the maximum sieve opening value. Applied to the data given by Herbst 5,6 for batch grinding of 7 X 9 mesh dolomite, the parameters given in Table 1 were obtained. The discussion of the significance of the residual sum of squares is a difficult subject in multiple nonlinear

Jan 1, 1972

By F. M. Lewis, Johnson. E. C.

BY now application of the liquid-solid cyclone to various classification problems in the chemical and metallurgical fields is more or less familiar. A less publicized application receiving wider consideration as time goes on is its use as a classifier in closed-circuit grinding operations. This paper presents the costs involved and the experience gained from operating a unit of this kind. In May 1951 the Tennessee Copper Co. installed in its London mill at Copperhill, Tenn., a liquid- solid cyclone in closed circuit with a 6x12-ft ball mill. The circuit in which this cyclone is used is the regrind or secondary grinding circuit of a copper flotation plant. Originally it consisted of a 7x1-ft conical ball mill in closed circuit with a bowl classifier. Changes made in the primary grinding circuit of the mill necessitated a regrind circuit of greater capacity. The bulk concentrate to be ground was raised from 900 or 1000 tpd to 1200 or 1300 tpd, and to accommodate this increase a 6x12-ft ball mill which had been in the primary grinding circuit was moved into the regrind circuit. When this was done it was found that the classifier was too small to give efficient operation. Space in the plant was at a premium, and since use of the cyclone offered considerable economy the installation shown in Figs. 1-3 was made.

Jan 6, 1954