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By W.C Ellis, Earle E. Schumacher

Nonferrous alloys upon which desirable properties can be conferred by heat treatment are becoming of increasing industrial importance. The alloys of copper with a constituent which has a solubility varying with temperature are materials of this character. Some of the constituents which are effective in producing a change in the mechanical properties of these alloys upon heat treatment are, according to Corson,' nickel and silicon, iron and silicon, cobalt and silicon, and chromium and silicon. In addition to these elements, Gregg2 states that the combination of beryllium and silicon is effective in producing age-hardening characteristics in copper. The effect of these elements, however, as dispersion-hardening constituents in the copper alpha solid solutions does not seem to have been studied in any considerable detail. This paper deals with the heat treatment and properties of three alpha brasses containing 3 per cent. of nickel plus silicon in the proportion necessary to form the compound nickel silicide, Ni2Si. Some information of a preliminary nature in regard to the hardening by heat treatment of phosphor bronze containing the same percentages of nickel and silicon is included. The method of hardening the alloys, which is effective in increasing the tensile strength and proportional limit, is similar to that used in the case of duralumin type aluminum alloys. It consists of a quench from a temperature at which the hardening constituent is in solid solution, followed by an aging at a lower temperature to precipitate the dissolved constituent in a dispersed condition. This results in an increased resistance of the alloy to deformation with an attendant improvement in the tensile properties.

Jan 1, 1929

By Earle E. Schumacher, W. C. Ellis

Nonferrous alloys upon which desirable properties can be conferred by heat treatment are becoming of increasing industrial importance. The alloys of copper with a constituent which has a solubility varying with temperature are materials of this character. Some of the constituents which are effective in producing a change in the mechanical properties of these alloys upon heat treatment are, according to Corson,' nickel and silicon, iron and silicon, cobalt and silicon, and chromium and silicon. In addition to these elements, Gregg2 states that the combination of beryllium and silicon is effective in producing age-hardening characteristics in copper. The effect of these elements, however, as dispersion-hardening constituents in the copper alpha solid solutions does not seem to have been studied in any considerable detail. This paper deals with the heat treatment and properties of three alpha brasses containing 3 per cent. of nickel plus silicon in the proportion necessary to form the compound nickel silicide, Ni2Si. Some information of a preliminary nature in regard to the hardening by heat treatment of phosphor bronze containing the same percentages of nickel and silicon is included. The method of hardening the alloys, which is effective in increasing the tensile strength and proportional limit, is similar to that used in the case of duralumin type aluminum alloys. It consists of a quench from a temperature at which the hardening constituent is in solid solution, followed by an aging at a lower temperature to precipitate the dissolved constituent in a dispersed condition. This results in an increased resistance of the alloy to deformation with an attendant improvement in the tensile properties.

Jan 1, 1929

By H. S. Munroe

The native copper of Lake Superior occurs in the form of fine grains and scales, disseminated in small percentage through the copper-bearing rock ; and in large and small masses, from a few pounds to several hundred tons in weight. Formerly the bulk of the copper came from the mines of Ontonagon and Keweenaw counties, producing mass copper. At present these mines furnish less than one-tenth of the total product, and fully one-half of this is from a single mine. The masses are usually found irregularly distributed in nearly vertical fissure veins, and require much dead work; in sinking, drifting, and stoping for their development. The risk and expense attending the working of these mines have made them, with few exceptions, anything but profitable.

Jan 1, 1880

By F. S. McNicholas, M. S. Walker, V. C. Rogers

During the year of 1944 and the first half of 1945, the Climax Molybdenum Co. made a study of some of the problems in block and panel caving, with the use of a scale model. The experiments dealt essentially with the type of rock and conditions at Climax, but some experiments were carried out to simulate conditions found in other mines. Most of the previous experiments on the caving characteristics of rock have dealt with sedimentary or broken igneous material. The series of experiments described here was designed to show the caving action of unbroken igneous rock. Con- siderable difficulty was experienced in duplicating unbroken material in the model. The results obtained are believed to be relatively correct, but verification must necessarily come from future mine operation. Observations in the mine and glory hole, together with statistical data, were used as criteria for creating similar conditions in the model. In 1913, George R. Lehman' experimented with broken material in a model for the Inspiration Consolidated Copper Co. and, more recently, P. B. Bucky2 experimented with broken material with a capping of mill tailings. Mr. Lehman's model represented a maximum ore height of 70 ft. capped by 55 ft. of waste. He varied the draw-hole spacing from 6¼ ft. to 8? ft. and 12½ ft. The material used graduated from fines to 30-in. maximum size. Some of his conclusions were: "(I) The less the distance between chute centers, the greater the extraction (Fig. I); (2) the higher the ore column, the greater the extraction; (3) the less the amount drawn at a time from each chute, uniformly, the greater the extraction of clean ore before the capping appeared, but not the greater the total extraction to a I per cent copper final product." (Fig. 2.) Professor Bucky concluded, in part: "(I) Drawing of ore may take place at any time from any finger and in any amount without affecting materially: (a)

Jan 1, 1946

By Carville E. Sparks, Rollin Farmin

Edward Thomas (U.S. Bureau of Mines, Washington, D. C.)—This excellent article on an ingenious and successful installation of wooden rock bolts loses much of its effectiveness through an attempt by the authors to establish the general adaptability of this type of support. Possibly because they have only local experience as a guide, they imply erroneously in the first paragraph that the Bureau of Mines has been opposed to wooden bolting, although later in the article reference is made to a Bureau publication on the subject. In 1947 the Bureau of Mines decided to sponsor experiments in roof bolting in coal mines because the experience of the St. Joseph Lead Co. had indicated that this type of roof support appeared to be a roof-fall accident-prevention measure that might be adopted and also effect economies in operating cost. Justification for this belief has been borne out, particularly in coal mining. This program has been carried out under the following general program: 1—The Roof Control Section of the Bureau of Mines has advocated and initiated underground experiments under controlled conditions with many different ideas related to rock bolting since 1947. In no instance has cooperation in developing an idea been refused, no matter how ridiculous it may have seemed at first glance, if it has been requested by a mining company. 2—The Bureau of Mines has no police powers over the selection of roof-support devices and seeks none. 3—At the request of an operator, the Bureau of Mines will make comparative tests on various types of bolts underground and will submit resultant data for the operator's consideration. 4—Wherever possible, the Bureau publicizes successful installations, so that others may benefit from this experience; however, it is careful not to discriminate between manufacturers of bolts or bolt-installation equipment. Unsuccessful experiments probably should also be publicized, but from a practical standpoint it is usually not feasible. In other words, the role of the Roof Control Section of the Bureau is in line with the original purpose for which the Bureau was first organized: to serve industry through gathering, analyzing, and disseminating factual data. It would seem to be logical that the starting point for any experimentation on roof bolts in coal mines should be the time-proved practice of the

Jan 1, 1955

By Clinton M. Ball

Magnetic iron-ore is found in many localities throughout this and other countries, in large bodies and in convenient proximity to other materials required for its conversion into iron and steel; and these bodies of ore would have great commercial value on account of their nearness to consuming markets if they were generally suitable in their natural state for use in the larger operations of steel-making. In the manufacture of iron and steel it has been found, however, that not all ores are equally valuable as sources of raw material for the finished products of furnace, forge and foundry; and, as is now well understood, this is because of the intrusion, in the process of formation of the ore-bodies, of substances which can enter into deleterious combinations with the iron itself, or form compounds associated with the iron oxide which will hinder, if they do not altogether prevent, the production therefrom of the higher grades of finished metal. It is only since the development of the modern method of steel-making by the Bessemer process that the art of the chemist has been called to a critical study of the nature and effect produced by the presence of these pernicious substances in the furnace while the iron is undergoing reduction to the metallic state. Phosphorus and sulphur are the most common and obnoxious elements, and the admixture of one or the other, or both of these, in small percentages and varying proportions, will greatly modify the final results of manufacture. It so happens that generally, although not always, these hurtful elements are found in compounds in the ore which are not magnetic, and this circumstance has led to the expenditure of much ingenuity and money over a long period of time, in attempts to utilize the attractive power of magnets to separate the magnetic oxide of iron out of its crushed ores and from sands, in

Jan 1, 1896

By H. Cecil Spicer

The results described in this article are based on field work conducted during the periods APril-May, 1939, and MaY-JulY, 1940. The United States Potash CO. is mining potash on Government land under a permit from the Department of the Interior and the geophysical investigation mas completed under a cooperative arrangemerit made between that company and the Conservation Branch of the Geological Survey. The writer, a member of the Section of Chemistry and Physics of the Geologic Branch, was assigned to this investigation. Four definite objectives were in mind for the geophysical work in the studies over the salt deposits. The first was to determine the measure of success that could be attained in this type of work with the resistivity methods that were to be employed. These methods had been introduced into the work of the Conservation Branch by Benjamin E. Jones for the investigation of dam sites, and have been used under his direction by the author for such work. If the method proved to be applicable, an l was to be made to contour the top of the salt beds and also the other formation boundaries known to be present in this area. Salt-water aquifers were to be studied in an effort to determine their boundaries, and an attempt was to be made to delineate the potash-bearing beds. Others have made, and reported, resistivity studies over saliferous deposits in different areas. Friedell and Messrs. Schlumberger2 reported geophysical work performed in the disrovery of the salt domes of Alsace; Carrette and Kelly3 described the geology of the same area. Leonardon and Kelly4 published a resistivity curve obtained over the Hettenschlag dome, and a further discussion of this same area was given by the Messrs. Schlum-berger5 in a communication. Messrs. Alty6 described studies 0" salt deposits in which the sing[e-probe method was used. Sinerez7 mentions that electrical methods were tried over salt deposits in Spain. Geoffrey and Charrin8 show a resistivity curve obtained over marl, gypsiferous marl and salt which is similar to that obtained over the New Mexico salt deposits. Kelly9 reported resistivity work performetl with the ground comparator of Zuschlag over the salt deposits near Syracuse, N. Y., where the Salina formation is at a depth of 700 to 800 ft. Some structural studies on the potash basin of Alsace are described by Poldini.10 Another single-probe resistivity study, made over salt deposits in New Mexico, is briefly described by Heiland,ll through the courtesy of Harry Aurand, of the Midwest Refining CO.

Jan 1, 1942

By H. Cecil Spicer

The results described in this article are based on field work conducted during the periods APril-May, 1939, and MaY-JulY, 1940. The United States Potash CO. is mining potash on Government land under a permit from the Department of the Interior and the geophysical investigation mas completed under a cooperative arrangemerit made between that company and the Conservation Branch of the Geological Survey. The writer, a member of the Section of Chemistry and Physics of the Geologic Branch, was assigned to this investigation. Four definite objectives were in mind for the geophysical work in the studies over the salt deposits. The first was to determine the measure of success that could be attained in this type of work with the resistivity methods that were to be employed. These methods had been introduced into the work of the Conservation Branch by Benjamin E. Jones for the investigation of dam sites, and have been used under his direction by the author for such work. If the method proved to be applicable, an l was to be made to contour the top of the salt beds and also the other formation boundaries known to be present in this area. Salt-water aquifers were to be studied in an effort to determine their boundaries, and an attempt was to be made to delineate the potash-bearing beds. Others have made, and reported, resistivity studies over saliferous deposits in different areas. Friedell and Messrs. Schlumberger2 reported geophysical work performed in the disrovery of the salt domes of Alsace; Carrette and Kelly3 described the geology of the same area. Leonardon and Kelly4 published a resistivity curve obtained over the Hettenschlag dome, and a further discussion of this same area was given by the Messrs. Schlum-berger5 in a communication. Messrs. Alty6 described studies 0" salt deposits in which the sing[e-probe method was used. Sinerez7 mentions that electrical methods were tried over salt deposits in Spain. Geoffrey and Charrin8 show a resistivity curve obtained over marl, gypsiferous marl and salt which is similar to that obtained over the New Mexico salt deposits. Kelly9 reported resistivity work performetl with the ground comparator of Zuschlag over the salt deposits near Syracuse, N. Y., where the Salina formation is at a depth of 700 to 800 ft. Some structural studies on the potash basin of Alsace are described by Poldini.10 Another single-probe resistivity study, made over salt deposits in New Mexico, is briefly described by Heiland,ll through the courtesy of Harry Aurand, of the Midwest Refining CO.

Jan 1, 1942

By Waldemar Lindgren

I. Introduction............790 II. Geological Feature*:........793 The Gold-Bearing Fissure- Veins........793 Contact Melamorphic Deposits.........798 Classification According to Age........ 799 Introduction...........799 Pre-Cambrian Deposits.........800 Cretaceous Veins of the Pacific Coast...... 801 Late Cretaceous or Early Tertiary Deposits (Central Belt).. 802 Tertiary Deposits..........804 Conclusions,...........808 III. Detailed Descriptions:.........811 United Stater...811 Alaska.. ..812 Arizona,..814 California ..816 Colorado .. ..818 Idaho...823 Montana...825 Nevada...829 New Mexico,..........831 Oregon...833 South Dakota..834 Utah...836 Washington.. 837 Wyoming..838 Appalachian States..........839 British North America..........840 Mexico ....843 I. Introduction. The precious metals. gold and silver. are the basis of the monetary systems of the world. It is. therefore. natural arid inevitable that widespread interest should be manifested in their

Jan 1, 1903

By R. E. Reed-Hill

Recently Levine applied the Conrad-Wiedersich17 equation where H is the activation enthalpy, v the activation volume, T* the effective shear flow stress, T the absolute temperature, and ? the strain rate, to an analysis of titanium single-crystal data. The activation energy as a function of testing temperaturs obtained from specimens oriented for single (1010) prismatic slip is shown in Fig. 12. This diagram indicates a different linear dependence of H on T in the temperature interval from 220° to 300°K than from 0° to 220°K. Levine interpreted the break in this curve as indicating a change in the thermally activated mechanism controlling the flow stress. The purpose of this communication is to point out that the data in Fig. 1 is not consistent with the concept of a flow stress controlled by a simple thermally activated mechanism between 220° and 300°K. The Conrad-Wiedersich relation assumed that the strain rate can be expressed by:

Jan 1, 1968

By P. J. Connors, William J. McCormick, F. B. Olender, Jerome F. Sheldon, Donald T. Mylar, Edgar T. Gregory, Owen S. Roberts, H. Colijn

A quiet revolution has taken place in the conveyor belt industry. Man-made materials, improved production facilities, better splicing techniques and emphasis on repair and maintenance have all contributed substantially to lowering material handling costs for the mining industry. Formerly the rubber industry had only cotton for a belt carcass and tree grown rubber for the protective cover. Monofilament rayon, with desirable elongation and elastic properties, was the first synthetic fiber to be used in place of cotton. But wet strength and other limitations restricted its use, and the conveyor belt industry turned to nylon.

Jan 3, 1972

"Butte originated as a placer mining camp. The first gold discovery was made in the year 1864, near what is now Main Street. Placer mining was vigorously prosecuted along Silver Bow Creek and in Missoula, Buffalo, Town and Parrot gulches for a period of five years, at the end of which time, in 1870, the camp was practically deserted. In the meantime, the quartz veins so prominently traceable over the hillsides were located, the first location being made by W. L. Farlin and called the Black Chief claim, and later restaked as the Travona. Reasoning from the presence of the gold placers, free-milling gold ores were eagerly looked for by the early prospectors. Claims covering the great Rainbow and other silver lodes were located in the sixties. The presence of valuable silver ores in these veins caused the staking out of many claims, believed to be valuable only for silver, but which later proved to be enormous copper producers.Treatment of these early discovered rich ores was first attempted in arrastres. Later, stamp mills were built. The Centennial dropping 10 stamps, was the first, and in 1875 Mr. Farlin built the Dexter 10-stamp mill, intro¬ducing chloridizing-roasting. More successful processes were soon introduced and several large mills built, among which were the Alice, Lexington, Silver Bow, Moulton and Bluebird, in all representing a total of 290 stamps. The silver mining industry reached its zenith in 1887 and declined rapidly in the early nineties, following the sudden drop in the price of silver in 1892.During this period of silver mining activity the business of copper mining was making rapid strides. Development of the veins, located as silver veins, had uncovered copper ore in many instances. There was great activity in ""claim staking'' in the years from 1871 to 1879, during which period most of the claims covering the present productive copper area were located."

Jan 1, 1913

By H. G. Papacharalambous, S. C. Sun

Experimental results indicate that wet cyclones could be effectively used for the preliminary classification of the tested synthetic abrasive materials, thus supplementing the currently used sedimentation method. An empirical formula is also proposed on the basis of the test data to calculate the particle size of separation. One of the basic operations in the abrasive industry is the classification of the crushed and ground materials into different sized products. The relatively coarse grains, plus 325 mesh, are commonly sized by dry screening with satisfactory results. On the other hand, however, the currently used grading tank, for classifying grains finer than 325 mesh, is intermittent. Consequently, it is difficult to operate efficiently and keep pace with erratic market requirements. Little success was made in an attempt to substitute air settling and continuous hydraulic settling for the grading tank, because size specifications1 for abrasive powders are very stringent and difficult to meet. Finally, a wet cyclone was chosen for experimentation. Even though wet cyclones have not been extensively used in the classification of abrasives; however, their performance as a classifier has been verified by Driessen2,4 on coal, McCarrel5 with manganese, and Herkenhoff6,7 on iron ore. Experimental work on silicon carbide, boron carbide, and fused alumina has shown that the cyclone

Jan 1, 1963

By W. S. Ayres

By Carl H. Samans

THE INFORMATION AVAILABLE on the rolling characteristics of the precious metals-gold, silver, the platinum metals and their alloys-is incomplete and mostly from scattered sources. In the present paper an effort has been made to assemble and correlate it and to fill in some of the gaps that exist. GENERAL ROLLING CHARACTERISTICS SOME EFFECTS OF IMPURITIES Gold and its alloys are generally considered to be hot short and hence are usually rolled cold. Cold rolling of the yellow, green, and pink gold alloys. Which customarily contain gold, silver, copper and zinc and frequently some nickel as well, introduces no new problems since reasonable reductions are quite feasible and the alloys show little tendency to fire crack in subsequent annealing. The white gold alloys. which usually contain little or no silver and 10 pct or more nickel, are very susceptible to fire cracking1 and hence wrist he given relatively heavy reductions, i. e., 8-10 pct or more per pass with a total reduction of about 50 pct between anneals, to minimize this tendency. In addition, it is preferable to keep the bar as flat as possible during rolling. Although no comprehensive study appears to have been made of the effects of impurities on the cold rolling characteristics of gold alloys, the observations of Nowack2 on the effects of small

Jan 1, 1948

By R. Lyndon Arscott, P. Hackett

This chapter reviews the early stages of a study designed to investigate the physical behavior of the coal measure rocks around longwall panels over a relatively large area. The aim of the work is to attempt to explain a directional tendency for a certain type of underground fracture. The geological structure of the area is reasonably uniform but the effect of some local anomalies is also discussed. Although some definite tendencies have been recorded, the results so far achieved need confirmation by further experiments. The chapter deals first with some in-situ strain measurements carried out in longwall panels and continues with a discussion of the relationships between induced fractures and the natural variations in the structure of the rock mass. Finally, some light is shed upon the gas outburst phenomenon although eradication of the hazard is far from assured. STRESS AROUND A LONGWALL PANEL Considerable progress has been made during the last few years towards the determination of the mechanism of failure of small samples of rock under varying environmental conditions. Much more laboratory testing needs to be done in this field but an even greater amount of study needs to be devoted to the extrapolation of laboratory phenomena to failure around underground excavations. The problem is made more difficult because the stress redistribution around an excavation is often difficult to define, particularly when part of the rock mass fails and a

Jan 1, 1972

By Samuel Wyer

1. THE following is an abridgment of a recent report made by the author, covering an investigation of (A) The necessary use of natural-gas compressors; (B) The effect of gas compressors on natural-gas field operating conditions in Ohio, with special reference to the working pressure relations of gas wells of one company discharging by natural rock pressure flow without compressors, and adjacent wells of other companies, discharging into intake lines to gas-compressing stations. Tests were made at 107 different places in the counties of Fairfield, Licking and Knox, Ohio, which required 7,000 miles of automobile driving, and consumed 6 months' time. 2. A proper conception of. the necessary use and effect of natural-gas compressors in natural-gas production necessitates a clear understanding of certain fundamental definitions and judicial doctrines, which are given herein. 3. Gas is a fluid composed of a large number of molecules which are vehicles of energy continually in motion, and having an inherent. tendency to get farther and farther apart. The range of motion of the molecules is limited only by the volume of the closed containing vessel in which they constantly move to and fro. The most distinguishing characteristic of gas is its universal property of completely filling an inclosed space.

Jan 2, 1916

By H. C. H. Darley

The influence of particle size and concentration on the development of chip hold-down pressure (CHDP) was studied in an apparatus designed to measure the change of filtration rate during the first second of the filtration process. CHDP is controlled by the "bridging" particles (i.e., particles in the 50 to 0.2 micron range), whereas filter loss is controlled by the colloid fraction. The results indicated that a fast drilling fluid with a low filter loss could be obtained if the concentration of bridging solids and the viscosity were kept very low. A novel group of drilling fluids, which we have named colloid emulsions, was developed to meet the above requirements. These colloid emulsions are made by dispersing art oleophilic colloid in oil and emulsifying about 5 per cent of this dispersion in water or a dense brine. Good results have been obtained in field trials with emulsions which use asphalt as the oleophilic colloid. INTRODUCTION In recent years it has been found that fast rates of penetration can be maintained in hard formations by using "clear" water as a drilling fluid. In some cases, however, water cannot be used because the very high down-hole filter loss creates various difficulties in drilling, in logging, or in producing the well. It then becomes necessary to "mud up", which results in a decrease in drilling rate. The reason that mud decreases drilling rates is a complex subject which has been well covered by such authors as Garnier and van Lingen, Cunningham and Eenink,' and van Lingen.3 One of the principal factors involved is the tendency of the drilling fluid to develop a filter cake on the bottom of the hole. The pressure differential which develops across this filter cake opposes the action of the bit in dislodging chips from the rock. This pressure differential is referred to by Garnier and van Lingen' as the chip hold-down pressure, which is denoted by the initials CHDP in this paper. The work described in this paper was undertaken to develop a drilling fluid which would minimize CHDP but which would still have a low filter loss—in other words, a fluid which would deposit a filter cake on the sides but would lay little or no filter cake on the bottom of the hole. EVALUATION OF CHDP EXPERIMENTAL Conditions governing the growth of filter cake on the sides of the hole are obviously different from those on the bottom of the hole. On the sides of the hole, cake will form continuously but at a decreasing rate, until eventually the rate of growth will equal the rate of cake erosion by the mud stream.' On the bottom of the hole, each time a bit tooth dislodges a chip the cake is removed, a fresh rock surface is exposed, and the filtration process must start over again. Thus the CHDP is determined by the amount of cake which can form in the interval between successive tooth strikes at a particular spot, normally a fraction of a second. Our first step therefore was to study filtration rates over the first second or so of the filtration process. These tests were conducted in the simple type of dynamic filter cell shown in Figs. 1 and 2. In this cell the mud was filtered through a train of rock cores while rotating blades kept the mud flowing over the surface of the core. The procedure was to evacuate the cores to 0.05 mm of mercury, saturate with brine, and assemble in the holder under brine. The permeability of the core train was then determined. A plastic seal was placed on the face of the core train, and a rip cord was attached from the seal to one of the blades. At the start of the test, 500 psi was applied to the mud, and the meniscus in the capillary measuring tube was adjusted to zero. When the blades were started, t,he seal was ripped from the face of the core, and filtration began. The filtration rate was at first measured by photographing the advance of the meniscus in the capillary tube. Using

Jan 1, 1966

Jan 1, 1905

By Richard Moldenke

A. E. OUTERBRIDGE, JR., Philadelphia, Pa. (written discussion).¬ The fact that iron castings improve with age has long been known. Many years ago the late Sir Frederick Bramwell, a distinguished engineer, formerly in charge of the metallurgical and gun-making department of the Woolwich Arsenal, England, determined to break up a large number of cast-iron mortars of an obsolete type that had been in stock for years. It was then reported to biro that it was found to be much more difficult to break these old gun castings under the "drop" than it was to break similar gun-castings recently made, under his own supervision; he changed the.. composition of the iron and still found that whenever castings made recently were broken up (on account perhaps of superficial defects) great disparity was observed in apparent strength between the old and new castings. Sir Frederick then made many other comparative tests, such

Jan 4, 1917