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By Lysle E. Shaffer

TEACHING engineering students how to write and speak effectively -is one of the greatest problems facing the technical schools today. No phase of engineering education has received more criticism, and rightly so, for the criticism is justified. Year after year we continue to graduate men that are indifferent to the use of a tool they will need every day of their lives. Our young engineers cannot write a clear, concise report, and their business letters are a disgrace to the profession that takes pride in precision. The problem is not new. The remark ascribed to Sir James Barrie, that "The man of science appears to be the only man who has something to say, just now-and the only man who does not know how to say it" is as uncomfortably true today as it was thirty years ago. The records of meetings of engineering educators and the transactions of the engineering societies show that the inability of the engineer to communicate his ideas has been discussed for years. Engineering educators, prodded by industry, have recognized that the problem exists, but they have not solved it. Instead they continue to expose the student to composition and rhetoric, hustle him through English and American literature, and then blame his high school because he does not know enough English grammar to write a clear sentence. We must face the fact that the graduate is not going to reflect on the high school, but on his college. If the high school has shirked the job, the responsibility for correction rests on the faculty of the professional school.

Jan 1, 1948

The Mascot-Jefferson City zinc mining district in eastern Tennessee has been a major zinc producer for over 60 years. The district lies within the Tennessee division of the Appalachian Valley and is underlain by folded and faulted Paleozoic rocks. The local formations are composed of limestones and dolomites with occasional shales, and sand- stones, and thin and scattered chert nodules. The regional structure of the district is unique in that it is complicated by irregular, distorted, and broken anticlines, synclines, domes, and major and minor post-ore folding and faulting.

Jan 5, 1976

By E. W. Wagy

The year 1927 witnessed numerous developments of significance in California. The State's shut-in production increased from an average of 58,000 bbl. daily in January to a maximum of 93,000 bbl. daily in August, and a total of about 25,000,000 bbl. was withheld from the market during the year. This not only lessened the effect of large production at Hunt-ington Beach, Seal Beach and Alamitos Heights, but also was a most effective conservation move. Since 1922, it is estimated that approximately 100,000,000 bbl. of oil that would otherwise have been produced have been held in the ground. I. Outstanding Field Developments of 19271 1. Long Beach Deep Sand. 2. Rincon (Seac1iff)Discovery. 3. Alamitos Heights Discovery. 4. Ventura Avenue Extension. 5. Round Mountain Discovery. 6. Mt. Poso Extension. 7. Potrero (Cypress) Discovery. 8. Buttonwillow Gas Development. 9. Goleta Discovery. 10. Union Avenue, Edison and Fruitvale Areas. (See Fig. 1.) II. Crude Production The most important factor in new crude production in 1927 was the Seal Reach field with its adjacent Alamitos Heights townlot area. Production increased from about 10,000 bbl. daily in January, to a peak of 66,000 bbl. in June. Huntington Beach finished the year 1926 with a production of 102,000 bbl. daily, which declined to 60,000 bbl. by the end of 1927. Due to production in these three areas and the tempering effect of shutting in numerous wells, the California production curve for 1927 was held at a fairly even level. Fig. 2, shows the State's production in 1927 and 1926 as compared with 1923, which was the year of excessive

Jan 1, 1928

By C. G. Fink, G. L. Putnam

The dissolution of gold by cyanide solutions was studied by determining the time required for the solvents to dissolve gold leaf. Minute traces, even 0.5 ppm, of sulphide ion retard the dissolution of gold, and this behavior cannot be accounted for by the presently accepted hypotheses involving oxygen-depletion or thiocyanate formation. On the other hand, traces of the salts of lead, bismuth, mercury, and thallium considerably accelerate the dissolution. The beneficial effect of lead is dependent upon the pH and cyanide ion concentration of the solution. ALTHOUGH cyanide solvents are used very ex-x*. tensively for the recovery of gold from ores and concentrates, the normal rate of solution of the precious metal as determined by Barsky, Swainson, and Hedley,1 and others2 is less than about 3 mg per sq cm of exposed gold surface per hour, corresponding to a corrosion depth of approximately 1.5 microns (0.00006 in.) per hr. Although the slow rate may be increased to some extent in certain cases, as, for example, when the the gold is partially imbedded in iron pyrites,3 the leaching operation is generally the most time-consuming step of the cyanide process. Frequently it is necessary for the leaching solvents to remain in contact with the ores for 50 to 200 hr in order to dissolve all of the gold particles.' Not only does the slow solution rate cause some increase in the capital costs, but the cyanide consumption also may be increased because of vaporization of hydrocyanic acid and secondary reactions with minerals such as malachite (CuCO3 • Cu(OH)2), and pyrrhotite, which often are associated with gold. It is not surprising that numerous attempts have been made to accelerate the dissolution of gold in cyanide solutions. Experimental Gold Leaf Test: The gold leaf test was apparently originated by M. Faraday, who, by means of it, discovered that dilute cyanide solutions would dissolve gold readily in the presence of oxygen. The usefulness and reliability of the test have been discussed elsewhere.5,6 Essentially, the method consists of determining the time required for 5-ml portions of cyanide solvents to dissolve squares of 23 carat gold leaf, 0.5 cm on edge, when shaken in 10-ml test tubes with the solvents. The weight of gold leaf per test was 0.051 mg as determined by the direct weighing of a leaf 8.6x8.6 cm (weight = 15 mg) and measuring the area of the test sample (0.25 sq cm). Gold leaf is of remarkably uniform thickness.6 Since gold leaf, like native gold, contains small amounts of copper and silver, the results are comparable with those one might expect in cyaniding gold ores. As six or more tests can be made simul- taneously, the relative efficiencies of the solvents can be evaluated readily. All dilute solutions of lead, bismuth, thallium and mercury salts were prepared by the ordinary dilution method used by chemists. Our C.P. sodium cyanide and buffering reagents had no detectable amounts of either sulphide ion or heavy metals. Soluble Sulphides in the Cyanide Process: The action of soluble sulphides is of interest in the study of the dissolution of gold in cyanide solutions. That gold ores which contain compounds of arsenic and antimony often are not amenable to direct cyanide treatment is well known, and it said that arsenic and antimony are "cyanicides."7 It is commonly believed that part of the sulphur content of such ores is soluble in alkaline solutions to give sulphide ion, which reacts with the free cyanide content of the leaching solutions to form inert thio-cyanates or reacts with the dissolved oxygen to form sulphites or sulphates.8 A purpose of this paper is to demonstrate that sulphide ion may behave in a manner that cannot be explained by either the oxygen-depletion or thiocyanate formation theories and to prove directly that concentrations of sulphide ion which cannot be detected even by colorimetric methods may retard the dissolution of gold.

Jan 1, 1951

By C. G. Fink, G. L. Putnam

The dissolution of gold by cyanide solutions was studied by determining the time required for the solvents to dissolve gold leaf. Minute traces, even 0.5 ppm, of sulphide ion retard the dissolution of gold, and this behavior cannot be accounted for by the presently accepted hypotheses involving oxygen-depletion or thiocyanate formation. On the other hand, traces of the salts of lead, bismuth, mercury, and thallium considerably accelerate the dissolution. The beneficial effect of lead is dependent upon the pH and cyanide ion concentration of the solution. ALTHOUGH cyanide solvents are used very ex-x*. tensively for the recovery of gold from ores and concentrates, the normal rate of solution of the precious metal as determined by Barsky, Swainson, and Hedley,1 and others2 is less than about 3 mg per sq cm of exposed gold surface per hour, corresponding to a corrosion depth of approximately 1.5 microns (0.00006 in.) per hr. Although the slow rate may be increased to some extent in certain cases, as, for example, when the the gold is partially imbedded in iron pyrites,3 the leaching operation is generally the most time-consuming step of the cyanide process. Frequently it is necessary for the leaching solvents to remain in contact with the ores for 50 to 200 hr in order to dissolve all of the gold particles.' Not only does the slow solution rate cause some increase in the capital costs, but the cyanide consumption also may be increased because of vaporization of hydrocyanic acid and secondary reactions with minerals such as malachite (CuCO3 • Cu(OH)2), and pyrrhotite, which often are associated with gold. It is not surprising that numerous attempts have been made to accelerate the dissolution of gold in cyanide solutions. Experimental Gold Leaf Test: The gold leaf test was apparently originated by M. Faraday, who, by means of it, discovered that dilute cyanide solutions would dissolve gold readily in the presence of oxygen. The usefulness and reliability of the test have been discussed elsewhere.5,6 Essentially, the method consists of determining the time required for 5-ml portions of cyanide solvents to dissolve squares of 23 carat gold leaf, 0.5 cm on edge, when shaken in 10-ml test tubes with the solvents. The weight of gold leaf per test was 0.051 mg as determined by the direct weighing of a leaf 8.6x8.6 cm (weight = 15 mg) and measuring the area of the test sample (0.25 sq cm). Gold leaf is of remarkably uniform thickness.6 Since gold leaf, like native gold, contains small amounts of copper and silver, the results are comparable with those one might expect in cyaniding gold ores. As six or more tests can be made simul- taneously, the relative efficiencies of the solvents can be evaluated readily. All dilute solutions of lead, bismuth, thallium and mercury salts were prepared by the ordinary dilution method used by chemists. Our C.P. sodium cyanide and buffering reagents had no detectable amounts of either sulphide ion or heavy metals. Soluble Sulphides in the Cyanide Process: The action of soluble sulphides is of interest in the study of the dissolution of gold in cyanide solutions. That gold ores which contain compounds of arsenic and antimony often are not amenable to direct cyanide treatment is well known, and it said that arsenic and antimony are "cyanicides."7 It is commonly believed that part of the sulphur content of such ores is soluble in alkaline solutions to give sulphide ion, which reacts with the free cyanide content of the leaching solutions to form inert thio-cyanates or reacts with the dissolved oxygen to form sulphites or sulphates.8 A purpose of this paper is to demonstrate that sulphide ion may behave in a manner that cannot be explained by either the oxygen-depletion or thiocyanate formation theories and to prove directly that concentrations of sulphide ion which cannot be detected even by colorimetric methods may retard the dissolution of gold.

Jan 1, 1951

By C. O. Brawner

The advent of larger drilling, excavation, and milling equipment is resulting in a tremendous increase in the scale and annual tonnage of open pit mining. At the present time, open pits up to 3000 ft. deep, and tailings dams and waste dumps up to 600 ft. high are being planned. One of the major problems that projects of this magnitude create is stability. Stability at open pit mining developments must be assessed for tailings dams, waste dumps, and open pit slopes in overburden soil and in rock. Soil mechanics principles are used to assess the stability for the first three. This science was developed by Dr. Karl Terzaghi in the 1920’s, and since that time the theories and principles have been tested and evaluated. This experience has resulted in the development of sound theoretical concepts, workable sampling and testing techniques, and accurate methods of analysis. Typical problems that can be analyzed include: -bearing capacity of soil under dams and waste dumps. - amount of seepage under and through dams. - stability of slopes and determination of safe slope angles for tailings dams, waste dumps, and open pits. - influence of earthquakes on stability. - influence and cost of different excavation and construction techniques. To assist in comparing engineering experience, an international soil classification system has been developed and used for several decades. In addition, many excellent text books are available outlining soil mechanics principles and techniques. A high degree of technology exists in soil mechanics. This, the mining engineer cannot afford to ignore. If soil mechanics principles had been applied, many major failures involving tailings, tailings dams, or waste dumps, such as those at Aberfan, Mufulira, Luanshya, and El Cobre would not have occurred. Tailings dams are planned in Canada that will be up to 600 ft. high. Construction procedures used in the past have paid little attention to the compaction of the shell material or to the influence of earthquakes on stability. This neglect has led to failures. While failures in low dams may not be too serious, for high dams such failures could have catastrophic results. Another major area of concern is the stability of rock slopes. From the standpoint of long

Jan 1, 1971

YEAR OF ELECTION 1913 FRANK DAWSON ADAMS Montreal, Canada 1921. WILLIAM CUTHBERT BLACKETT Sacriston, Durham, England 1923 GELASIO CAETANI Washington, D C 1920. HENRY STURGIS DRINKER Merion Station, Pa 1921 FERDINAND FOCH Paris, France 1922. FEDERICO GIOLITTI . Torino, Italy 1888. HATON DE LA GOUPILLIERE Paris, France 1906 SIR ROBERT A. HADFIELD London, England 1921. FRANK WILLIAM HARBORD London, England 1921. HEINRICH O HOFMAN Cambridge, Mass 1917 HERBERT HOOVER . Washington, D C 1915 JAMES FURMAN KEMP New York, N. Y 1905 HENRI LECHATELIER Paris, France 1921. C. McDERMID London, England 1913 EZEQUIEL ORDONEZ Mexico City, Mexico 1909 ALEXANDRE POURCEL Paris, France 1911 ROBERT H RICHARDS Cambridge, Mass 1907 CHARLES D WALCOTT Washington, D C

Jan 1, 1923

By Z. T. Bieniawski, E. Unal, H. Reginald Hardy

INTRODUCTION Rock bolts are a major means of support in underground coal mines in the United States. However, two of the most crucial problems facing the mining engineer today are that of finding a well defined and standard method for testing the anchoring ability of rock bolts, and of selecting the most suitable type of rock bolt and bolting pattern for a particular mine or specific mine section (Anon., 1982). Such selection requires not only an understanding of the behavior of the rock mass and the rock-bolt unit itself, but also a knowledge of the basic mechanisms by which rock bolts provide support while they interact with the rock mass during various field loading conditions. A recent study in this area has shown the inadequacy of present methods used in selecting and testing of rock bolts and the lack of clearly defined guidelines for safe and economical design of bolting patterns (Bieniawski, et al., 1980). The present paper describes a research study aimed at developing laboratory instrumentation and associated techniques for the evaluation of bolt-rock interaction. The instrumentation system developed, procedures followed during various experiments, and typical results from a series of studies carried out on mechanical bolts are presented. DEVELOPMENT OF THE ROCK BOLT TESTING FACILITY General A block diagram of the experimental facilities are shown in Fig. 1. The system consists of three main sections. The first

Jan 1, 1982

By William Garrett

I have heard it said that the late Mr. Holley made use of this remark: " There is an inherent, cussedness about rolls which, so far, no man has been able to find out." I think this can be safely claimed in reference to steel, as there are certain peculiarities about it that are pretty hard to account for. Previous to the introduction of the Bessemer process there was, as it were, a great chasm between iron and crucible steel; and, outside of what futile attempts had been made in puddling steel, nothing had been done to fill this gap. The Bessemer steel struck a medium between the two, the softest of it not being able to take the place of good iron, while the hardest was not suitable to encroach very far upon the crucible-steel trade. The open-hearth process made quite an inroad into the latter, but only for the lower and cheaper grades; and, beyond a doubt, for the finest grades of tool-steel, the cruciblesteel business has a long life before it. On the other side of the line comes the " basic " process, which brings us a step nearer iron ; but to fill up the gap completely, comes the Clapp-Griffiths process, which makes a grade of material—call it what you will—that is as soft as iron, welds as readily, and is in a fair way to supersede iron altogether. For fifteen years, I was in the employment of the Cleveland

Jan 1, 1886

By J. Chipman, H. Towers, M. Paris

A simple radioactive tracer technique is used to measure the diffusion coefficient of calcium ion in molten slags. In a slag of 40 pct Ca0-40 pct Si0,-20 pct Al203, Dc " at 1450°C is 1.3x10-6 cm' sec-'. THE application of the principles of thermodynamics to steel and iron making problems has proved so fruitful that the kinetic approach has tended to be neglected. It seems probable that in some reactions the rate-determining step is the dif-fusivity of the reactants or of the products. But knowledge of the diffusion coefficients of the constituents of liquid slag and metal is singularly lacking. The present work was undertaken as a first step toward supplying such data for slags. Furthermore, any additional information on the physical properties of liquid slags might be expected to help in elucidating their structure. It is essentially a preliminary investigation, the course of which was determined more by the necessity of establishing a method than by the immediate intrinsic interest of the results. For example, the selection of calcium ion to be studied was dictated by the suitability of the isotope Ca45 in that it is a simple emitter with a long half-life. Of the other ions commonly encountered in slags, the isotopes of iron and manganese have relatively complex radiations as well as the normal disadvantage of requiring control of the oxygen potential of the atmosphere; Mg27 and Al29 have half-lives measured only in minutes; Si3' has a simple decay process but its half-life of 2.8 hr is too short for preliminary studies; the only useful oxygen isotope is the stable O18; and there remain only sulphur and phosphorus both of which have suitable isotopes but were rejected as being of less fundamental interest than calcium. Similarly a lime-alumina- silica slag was used in preference to calcium silicate primarily because of its low melting point and its capacity to form a glass on fairly rapid cooling. Literature Review Very few studies of diffusion in liquid silicate systems have been reported. In order to determine the origin of diopside inclusions in felspathic rocks, Bowen1 investigated the diffusion between diopside and various mixtures of albite and anorthite. Platinum crucibles were used with diopside, the heavier of the two liquids, forming the lower half of the cell and diffusion taking place against gravity. Change in concentration along the diffusion path was found by measuring the refractive index of the quenched glass. Nearly thirty years later McCallum and Barrett2 used essentially the same method to determine the diffusion coefficient of lime in lime-alumina-silica slags. In this case the interest was to find the rate-determining step in the process of slag attack on refractory materials. In an investigation of the kinetics of the sulphur reaction, Derge, Philbrook, and Goldman8 determined the diffusion coefficient of sulphur in a typical blast furnace slag by the simple procedure of melting a slag containing 2 pct S over an identical slag sulphur-free. They make no claim to a high degree of accuracy but suggest that D, is of the order of 10-6 cm2 sec-l. Other high temperature liquid diffusion studies have been concerned with metals. Holbrook, Furnas, and Joseph4 determined the diffusion coefficients of silicon, phosphorus, sulphur, manganese, and carbon in liquid iron by immersing a small carbon crucible containing pure iron-carbon alloy in a large vessel containing iron with a high concentration of the particular element. Their results were confirmed by Paschke and Hauttmann5 using a similar method. Diffusion coefficients in silicates in the glassy state have been studied by Johnson, Bristow, and Blau6 Both Na24 and Ca45 were used as tracers but only the

Jan 1, 1954

By R. A. Bergier

The Transactions of the Institute contain nothing, as yet, on the subject of pocket-compasses; and in the belief that American miners, explorers, geologists, and engineers will gladly welcome any infor mation about new forms of apparatus, simple in construction and adapted to rapid use, I offer a short description of an improved French combination pocket-compass, which, if once introduced into use, would seem likely to supersede similar instrumens of older pattern. The instrument in my possession I owe to the kindness of M. G. de.La Bouglise, of Paris. The frame of the compass is a double-bottomed box, 2 1/2 inches square and 9/16 of an inch high, made of white metal, and with its sur faces very carefully planed. The sides of the box make true right angles with each other. Two sides are parallel with, and two are normal to, the north and south line of the principal graduation. The bottom is accurately planed, so that the instrument will lie true on a plane surface. A glass, 2 3/8 inches in diameter, is set in the top plate. The graduation for the needle is engraved on the upper face of a ring, connected with the flat disk, in which the center-pin is in serted. Between this disk and the bottom of the box there is a hollow space a quarter of an inch deep. The needle is 1 7/8 inches in length, and can be balanced by means of a small sliding piece of metal. The graduation extends from 0° to 360°, reading from right to left. The stopping of the needle is effected by a screw, A, on the side of the box near the handle, H (Fig. 1). There is also a clinometer attachment, the graduation for which is engraved on the upper face of the silver-plated disk. The compass has two sights. The north sight, B, is a simple pin, a little more than an inch high, which, when not in use, is kept folded down, and is partially protected by the exterior sliding-plate, C. When raised for use, the sight is stopped in a vertical position by a projecting pin attached to the side of the box.. The south sight, D, is connected with the handle, H, and the sight and handle

Jan 1, 1890

By R. A. David, D. J. Vink, D. L. Katz

A phase diagram showing boundary curve and quantity of liquid in the two-phase region was determined for a mixture of natural gas and natural gasoline in the region of its critical conditions. The temperatures and pressures of phase measurements were in the range of 85 to 212 F. and 1300 to 2600 Ib. per sq. in., respectively, with the critical conditions at 169.5 F. and 2615 Ib. per sq. in. abs. Color phenomena were observed in the region of the boundary curve from 102' to 192 F. Approximate densities of the single-phase and two-phase regions and analysis of the system are included. Boundary curves between the single-phase and the two-phase regions have been determined for several binary mixtures containing hydrocarbons. 2,3,4.6,7,10,11,12,14 These investigators did not report the relative amounts of liquid and vapor within the two-phase region. The equilibrium values obtained from the dew-point and bubble-point data can be used to compute the lines showing percentage of liquid on the pressure-temperature phase diagram8 but the positions of the lines near the critical temperature and pressure are uncertain. Relative amounts of vapor and liquid were obtained for a gasoline and a naphtha1 within the two-phase area but not in the region of the critical temperature and pressure. The bubble-point and dew-point lines, as well as the percentage liquid lines within the two-phase region, were determined by visual observations in glass apparatus. Apparatus An arrangement of the apparatus is given in Fig. 1, showing the Jerguson gauge A with glass windows B. Pressure was supplied by the

Jan 1, 1940

By R. A. David, D. L. Katz, D. J. Vink

A phase diagram showing boundary curve and quantity of liquid in the two-phase region was determined for a mixture of natural gas and natural gasoline in the region of its critical conditions. The temperatures and pressures of phase measurements were in the range of 85 to 212 F. and 1300 to 2600 Ib. per sq. in., respectively, with the critical conditions at 169.5 F. and 2615 Ib. per sq. in. abs. Color phenomena were observed in the region of the boundary curve from 102' to 192 F. Approximate densities of the single-phase and two-phase regions and analysis of the system are included. Boundary curves between the single-phase and the two-phase regions have been determined for several binary mixtures containing hydrocarbons. 2,3,4.6,7,10,11,12,14 These investigators did not report the relative amounts of liquid and vapor within the two-phase region. The equilibrium values obtained from the dew-point and bubble-point data can be used to compute the lines showing percentage of liquid on the pressure-temperature phase diagram8 but the positions of the lines near the critical temperature and pressure are uncertain. Relative amounts of vapor and liquid were obtained for a gasoline and a naphtha1 within the two-phase area but not in the region of the critical temperature and pressure. The bubble-point and dew-point lines, as well as the percentage liquid lines within the two-phase region, were determined by visual observations in glass apparatus. Apparatus An arrangement of the apparatus is given in Fig. 1, showing the Jerguson gauge A with glass windows B. Pressure was supplied by the

Jan 1, 1940

By H. Cecil Spicer

The results described in this article are based On field work conducted during the periods April-May, I939, 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 was 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 be an effort 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. Earlier Studies Others have made, and reported, restivity studies over saliferous deposits in different areas. Friedell and Messrs. Schlumberger2 reported geophysical work performed in the discovery of the salt domes of Alsace; Carrette and Kelly? described the geology of the same area. Leonardon and Kelly' published a resistivity curve obtained over the Hettenschlag dome, and a further discussion of this same area was given by the Messrs. Schlumberger6 in a communication. Messrs. Alty6 described studies on salt deposits in which the single-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 performed with the ground Comparaor 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,11 through the courtesy of Harry Aurand, of the Midwest Refining co, Geological Features OF Area Covered The area discussed in this paper is in Eddy County, southeastern New Mexico, a

Jan 1, 1946

By H. Cecil Spicer

The results described in this article are based On field work conducted during the periods April-May, I939, 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 was 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 be an effort 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. Earlier Studies Others have made, and reported, restivity studies over saliferous deposits in different areas. Friedell and Messrs. Schlumberger2 reported geophysical work performed in the discovery of the salt domes of Alsace; Carrette and Kelly? described the geology of the same area. Leonardon and Kelly' published a resistivity curve obtained over the Hettenschlag dome, and a further discussion of this same area was given by the Messrs. Schlumberger6 in a communication. Messrs. Alty6 described studies on salt deposits in which the single-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 performed with the ground Comparaor 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,11 through the courtesy of Harry Aurand, of the Midwest Refining co, Geological Features OF Area Covered The area discussed in this paper is in Eddy County, southeastern New Mexico, a

Jan 1, 1946

United Engineering Trustees, Inc. W. D. B. MOTTER, JR., '44 A. L. QUENEAU, '45 ALBERT ROBERTS, '43, President The Engineering Foundation GEORGE D. BARRON, '44 F. F. COLCORD. '46 A. L. QUENEAU, '45, Chairman

Jan 1, 1943

By S. S. Arentz

PLANNED health and safety programs have become an essential part of American industry because such programs lead to increased operating efficiency, improved labor relations, better public relations, and to substantial savings in compensation insurance. Those of you who have had the unpleasant duty of informing the wife or widow of one of your men of his serious injury or death while on the job, know that all the benefits of a successful safety program do not show on the balance S. S. ARENTZ, Member AIME, is General Superintendent, Nevada Operations, Combined Metals Reduction Co., Pioche, Nevada. AIME San Francisco Meeting, February 1949. TP 2741 A. Discussion of this paper (2 copies) may be sent to Transactions AIME before March 31, 1950. Manuscript received Jan. 6, 1949. sheet. These programs are of particular importance to the mining ,industry because mining's reputation as an unusually hazardous industry and the commonly isolated location of mining operations tend to focus attention on these problems. Description of Operations: Before proceeding with a discussion of our health and safety programs at Pioche, it may be proper to give a brief description of Pioche and of our operations there. Pioche is one of the early Nevada mining camps. It was founded shortly after the discovery of high grade silver ore in 1863 and mining has continued with more or less regularity to the present day. In an era of lawlessness, Pioche was notorious. The story persists that 75 men died with their boots on before one died a natural death, and old payroll records show that nearly as many gunmen were employed to stand off claim jumpers as there were miners working the mine. That was probably as close to a safety program as the times permitted. Pioche is situated in southeastern Nevada on the main highway between Ely and Las Vegas. The camp is on the flank of "Treasure Hill," near the original silver discovery, at an elevation of about 6000 ft. The present day population of about 2000 is primarily dependent upon the mines of the area, although Pioche also serves as the county seat of Lincoln Couqty and as the center of the surrounding livestock industry. The camp is served by a branch of the Union Pacific Railroad and receives power from the generators at Hoover Dam. The Pioche operations of the Combined Metals Reduction Co. were started in 1923 when the first complex lead-zinc ore was shipped to the company's mill at Bauer, Utah. The modern mill at Pioche was completed in 1941. The operations are medium sized in the nonferrous field, employing an average of 350 men in the mine, mill, and related works. The complex lead-zinc ore is mined from replacement deposits in a comparatively flat, extensively faulted, limestone horizon. Mining methods vary from stull-supported open stopes to filled square-set stopes. The thin bedded limestone and shale overlying the ore is allowed to cave as areas are mined out and caving frequently follows closely upon ore extraction. The relatively heavy ground and the numerous faults add to the problems of safe mining. The mine is well mechanized and the mill and surface plant are modern and well equipped. Labor is organized in a C.I.O. union and labor-management relations have been unusually harmonious. During most of the period since 1923 a competent supervisory staff worked to reduce safety hazards but the primary responsibility for safety rested on the individual workman. Accidents happened and all too frequently they were regarded by all concerned as unavoidable. In October 1939, the late Robert L. Dean became superintendent at Pioche. Most of his previous experience had been in the fields of iron and coal mining and from that experience he brought the concept that no accident is unavoidable. Many of the features of our present health and safety programs were initiated by Mr. Dean during his term as superintendent. Health Program: Our health program centers in Dr. Q. E. Fortier and his new, well-equipped, and well-staffed, modern hospital in Pioche. The program starts with a thorough pre-employment physical examination and is followed by yearly re-examinations at the expense of the company. The Pioche Mutual Benefit Association, to which all Pioche mine operators and employees belong, pays benefits covering hospitalization and surgery expense incurred by employee members and their families. The Association is governed by a board of directors elected by its members. The mine operators of the district donated the original capital and pay the monthly dues of the employee members. The employees pay the dues covering members of their families. Though not strictly a part of the

Jan 1, 1951

By S. S. Arentz

PLANNED health and safety programs have become an essential part of American industry because such programs lead to increased operating efficiency, improved labor relations, better public relations, and to substantial savings in compensation insurance. Those of you who have had the unpleasant duty of informing the wife or widow of one of your men of his serious injury or death while on the job, know that all the benefits of a successful safety program do not show on the balance S. S. ARENTZ, Member AIME, is General Superintendent, Nevada Operations, Combined Metals Reduction Co., Pioche, Nevada. AIME San Francisco Meeting, February 1949. TP 2741 A. Discussion of this paper (2 copies) may be sent to Transactions AIME before March 31, 1950. Manuscript received Jan. 6, 1949. sheet. These programs are of particular importance to the mining ,industry because mining's reputation as an unusually hazardous industry and the commonly isolated location of mining operations tend to focus attention on these problems. Description of Operations: Before proceeding with a discussion of our health and safety programs at Pioche, it may be proper to give a brief description of Pioche and of our operations there. Pioche is one of the early Nevada mining camps. It was founded shortly after the discovery of high grade silver ore in 1863 and mining has continued with more or less regularity to the present day. In an era of lawlessness, Pioche was notorious. The story persists that 75 men died with their boots on before one died a natural death, and old payroll records show that nearly as many gunmen were employed to stand off claim jumpers as there were miners working the mine. That was probably as close to a safety program as the times permitted. Pioche is situated in southeastern Nevada on the main highway between Ely and Las Vegas. The camp is on the flank of "Treasure Hill," near the original silver discovery, at an elevation of about 6000 ft. The present day population of about 2000 is primarily dependent upon the mines of the area, although Pioche also serves as the county seat of Lincoln Couqty and as the center of the surrounding livestock industry. The camp is served by a branch of the Union Pacific Railroad and receives power from the generators at Hoover Dam. The Pioche operations of the Combined Metals Reduction Co. were started in 1923 when the first complex lead-zinc ore was shipped to the company's mill at Bauer, Utah. The modern mill at Pioche was completed in 1941. The operations are medium sized in the nonferrous field, employing an average of 350 men in the mine, mill, and related works. The complex lead-zinc ore is mined from replacement deposits in a comparatively flat, extensively faulted, limestone horizon. Mining methods vary from stull-supported open stopes to filled square-set stopes. The thin bedded limestone and shale overlying the ore is allowed to cave as areas are mined out and caving frequently follows closely upon ore extraction. The relatively heavy ground and the numerous faults add to the problems of safe mining. The mine is well mechanized and the mill and surface plant are modern and well equipped. Labor is organized in a C.I.O. union and labor-management relations have been unusually harmonious. During most of the period since 1923 a competent supervisory staff worked to reduce safety hazards but the primary responsibility for safety rested on the individual workman. Accidents happened and all too frequently they were regarded by all concerned as unavoidable. In October 1939, the late Robert L. Dean became superintendent at Pioche. Most of his previous experience had been in the fields of iron and coal mining and from that experience he brought the concept that no accident is unavoidable. Many of the features of our present health and safety programs were initiated by Mr. Dean during his term as superintendent. Health Program: Our health program centers in Dr. Q. E. Fortier and his new, well-equipped, and well-staffed, modern hospital in Pioche. The program starts with a thorough pre-employment physical examination and is followed by yearly re-examinations at the expense of the company. The Pioche Mutual Benefit Association, to which all Pioche mine operators and employees belong, pays benefits covering hospitalization and surgery expense incurred by employee members and their families. The Association is governed by a board of directors elected by its members. The mine operators of the district donated the original capital and pay the monthly dues of the employee members. The employees pay the dues covering members of their families. Though not strictly a part of the

Jan 1, 1951

By Harlowe Hardinge, R. C. Ferguson

Laboratory and plant data covering 12 different operations show that lower than "standard" ball mill speeds increase grinding efficiency. In the case of high pulp-level mills, the gain is so great that the increase in capital cost of the larger lower speed mill will pay for itself in less than a year's time.

Jan 1, 1950

By August Wendel

weight, and deflection, and recommends that the Pennsylvania Railroad Company denland that rails be made on specifications, based on these six variables, so narrow, that to fill them would cause the constant rejection of enormous quantities of steel, and a consequent enhancement of the price of rails, probably ten or twenty per cent., without any certainty that such rails would be any better than those the steel-mills are now making. I earnestly hope that the investigation which Dr. Dudley has so ably carried on will be continued. I hope the Pennsylvarlia Sailroad Company, or preferably a combination of several railroads, will institute the prolonged investigation which I think will be necessary to solve this deep problem; that they will take a hundred or more rails, watching and noting down carefully every detail of their manufacture as well as their analysis; that they will be carefully weighed before, during, and after service; that their crop-ends will be tested before service, and the rails themselves after removal; that all the sources of error which Dr. Dudley admits in the present investigation may be removed, and that enough facts may be gathered and tabulated so that the conclusions which may be drawn from them may be apparent to every one without labored discussion or heated argument. But I venture to prophesy that after this investigation shall have been completed, and a formula adopted which shall be satiefactory to both manufacturers and consumcrs, that formula will not be the one now under discussion. I hope Dr. Durlley will pardon me if I have been unduly severe in my criticism, and consider that I have written my remarks hastily and at a time which should have been given to needed rest. I differ with him only as regards the conclusions which he has drawn. I appreciate the value of his labors, and only make public my own conclusions in the hope of contributing to the advancement of the science of steelmaking, in which we are ail so deeply interested. Dr. August WENDEL, Troy, K. Y.: Dr. Dudley's last paper gives, certainly, very valuable and interesting information regarding the wear of rails under different conditions. His results concernillg the composition of rails, explotle, rather startlingly, some old theories regarding the wear of rails, and 1 think after his formula is silnplified it will be one good formula to work by. As he now arrives at the same conclusions reached ill his first paper, some of my remarks will apply to both, althougl~ I would

Jan 1, 1881