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By W. C. Schroeder

PRACTICAL experience has shown that at elevated temperatures solu-tions containing sodium hydroxide may attack stressed steel in a manner that cannot be explained in terms of ordinary corrosion. Because the ductility of the metal has been greatly reduced during the reaction, the entire phenomenon is usually called "embrittlement." Thus, after several years of operation caustic evaporators have been so badly embrittled that rivets could be cracked off with the blow of a hammer. Since fine intergranular cracks are almost always present in the zone of fracture, it has often been assumed that a process of selective corrosion in grain boundaries was responsible for the failure, although this has not been clearly proved experimentally. Concentrations of sodium hydroxide below those necessary for the uniform, rapid attack of the steel surface are reported to be most effective in producing embrittlement2,3. In the operation of steam boilers a similar type of failure has been found, mainly in riveted seams or other capillary spaces where the solu-tion may concentrate and where high stresses may also exist. It is believed that in such localized areas the dissolved solids may reach a value many times the few hundred parts per million prevalent in the body of the boiler. While this type of boiler failure has been the subject of investigation for a period of 20 years', an understanding of its mecha-

Jan 1, 1936

By Donald E. Crowell

In the fall of 1969, ASARCO and Newmont Mining Co. began the design of the 700tpd concentrator at their Black Cloud shaft located near Leadville, Colo. The concentractor would treat by flotation a Pb-Zn-Ag ore containing minor gold values. Flowsheet design was based on laboratory test work performed at the Minerals Research Testing Laboratory of ASARCO. Since the concentrator is located at an elevation of 11,000 ft, cold weather was a major factor in design considerations. The original capacity was designed as 700 tpd but for various reasons an ultimate capacity of 1,000 tpd was desired. This necessitated special consideration in the design of several areas, particularly the grinding circuit. The grinding circuit chosen was a single 9 X 12 ball mill operating in closed circuit with one 20-in. cyclone. The ball mill will operate at low speed and as an overflow type originally. The mill can be speeded up and converted to grate type for handling the larger tonnage when required. Thickeners and filters were oversized and space was left for additional flotation cells in order to handle the increased tonnage in these areas. Pumps were sized so that they could handle the increased tonnage by increasing their speed. Construction began in May 1970; the Black Cloud concentrator went on-stream in April 1791.

Jan 1, 1974

In the late 19th century Fremont Pass was only a gateway to Leadville, Colo., 12 miles to the north. Some of the silver, lead, and zinc won from this famous camp crossed the Continental Divide at Climax, passing by the huge outcrop of molybdenum on Bartlett Mountain. This element, relatively un- known in the world of commerce, was then nothing more than a joke to play on greenhorn prospectors. Even 30 or 40 years later, after the demand for metals created by World War I had forced temporary use of molybdenum as an alternate for tungsten in tool steels, the Bartlett Mountain outcrop once again became merely a curiosity. With the persistent efforts of Brainerd Phillipson, for years the president of Climax and almost the only employe, use of molybdenum gradually began to grow, first in tool steel and later in the alloy steels required by the growing automotive industry. Mr. Phillipson was first an engineer and second a salesman. The combination of these two qualities is the key to the story, not only of Climax sales but also of the growth of molybdenum from an object of idle curiosity to the point where it is today, along with chromium and nickel, one of the most versatile alloying elements in the iron and steel industries and increasingly important in chemistry.

Aug 1, 1955

By L. O. Bond, R. P. Alger, A. W. Schmidt

Well logging provides valuable information for planning coal mining operations. In addition to locating, defining, and evaluating coal beds, electrical logs indicate the relative competence of roof and floor formations. Electrical well logging is the .recording of various physical, chemical, or physicochemical properties of the strata penetrated by a drill hole. To perform logging operations, borehole measuring probes, or sondes, are lowered on a cable into the drill hole. Insulated conductors in the cable pass power to the sonde and transmit signals to the surface. As the sonde is pulled up the hole, the measurements are recorded as a well log. These measurements serve to define the formation lithology. Common rock minerals exhibit characteristic log values such that computer analysis of the log data defines the mineral content of the formations. Shales, carbonates and sandstones, and coal beds are readily distinguished. Furthermore, preliminary results in coal studies indicate the log data delineates variations in ash and moisture contents. Of major concern in planning mining operations is knowledge of roof and floor competence. Here again the logs provide valuable information. Measurements of formation density and acoustic wave velocity provide data for computation of a compressional modulus. This compressional modulus is an effective index of formation competence. Electrical logging thus efficiently provides information for economic planning of mining operations.

Jan 1, 1972

By Yap Chu-Phay

IN the previous paper, the writer showed how, on the basis of thermodynamic reasoning, it seems probable that when true equilibrium conditions obtain, carbon exists as Fe3C in the liquid state and as elementary carbon in the solid state (7 Fe), in which case the solidus would be a straight line from 0.18 to 1.70 per cent. carbon (Fig. 1). In the same paper he concluded that the solidus obtained by Honda 'and his co-workers1 probably does not represent the same conditions, insuring a complete equilibrium. Except for a downward temperature displacement, the solidus obtained by Gutowsky,2 using the Heycock and Neville method, practically coincides with Honda's solidus as shown in Fig. 1. The writer at first thought that perhaps in some way Gutowsky's thermocouple was improperly calibrated for high-temperature measurements, as his liquidus was also much lower than those obtained by Carpenter and Keeling3 and by Ruer and Goerens.4 However, the eutectic temperature obtained by Gutowsky agrees with the generally accepted value of 1130° C., so that the validity of the inference regarding improper temperature calibrations is to be strongly doubted. In Fig. 1, Gutowsky's solidus is shown both in the original and in the corrected form. In the latter, a correction of 29.2° C. is made for all temperatures above 1416° C. in accordance with-

Jan 1, 1931

By R. C. Davis, R. F. Berry, G. W. White, B. T. O’Connell, L. A. Stacha

P,, and v, may now be solved for by trial and error between Eqs. 2 and 3, by assuming time approaching zero and equating PI, to P12. Observe that the pressure under the slug, P12 of Eq. 3, does not remain equal to the P1, at the valve in Eq. 2 as the slug proceeds up the hole. To plot the profile of pressure vs depth, it is necessary to express P12 in terms of P11. To do so, the extent to which the original submergence length S changes with respect to time must be analyzed. At the end of time t after injection, the actual value of L in Fig. 3 is The fall-back v,(t) is now distributed in the gas and exerts pressure on the bottom. This, in addition to the weight of the gas, amounts to the difference in pressures from point to point. With the average pressure profile calculable, a true numerical value for the average pressure in the tubing may be obtained. The value of v, must be obtained experimentally, and since v,, S and D are known, the basic Eq. 1 may be solved for the amount produced. Knowing P, and the actual volume of tubing occupied by gas (vat), it is possible to calculate the volume of gas at standard conditions which is present in the

By William Plank

In practically all rock-excavation problems there is need for a careful study of the rock structure, its fault, cleavage or bedding planes, and even the texture of the rock itself. These studies should form the bases upon which an excavation method is selected and they should be carefully considered in predicting the amount and extent of the excavation. The need for such studies was forcibly illustrated in the problems involved in a cut made in 1929, along and underneath a 200-ft. high rock projection for a State-highway near the City of Easton, Pennsylvania. The rock mass was badly faulted and also contained a number of cleavage planes at approximately right angles to the fault planes. Much of this structure was visible and could have been studied and analyzed before' the work was begun. The State had rigid specifications as to finished grade and slope of cut, which apparently were made without reference to the geologic structure. The contractor complied with the specifications, under the close inspection of the State engineers. A tunnel blast was, placed in the base of the cliff, with the result that 65 per cent more rock was broken than was intended by the specifications. About four years after the blast, the writers of this paper studied the circumstances surrounding the operation, to determine the cause of this excess excavation.

Jan 1, 1935

By R. F. Marande, R. S. Busk

THE magnesium-aluminum-zinc system contains most of the magnesium-base alloys used commercially, although in practice the ternary, alloys are usually modified by the addition of a small amount [ ] of manganese. Table I contains the magnesium-base commercial sand-casting alloys most widely used throughout the world, together with their typical tensile properties. These alloys may be regarded as a single family of varying aluminum and zinc content, disregarding manganese. A concise means of presenting data for them is by means of iso-property lines plotted on triangular coordinate paper. Constitutional, casting, and mechanical properties are presented in this manner. The data are given with the object of providing reference material, and to aid in the choice of a commercial alloy to serve a particular purpose. Detailed, critical analysis of the commercial alloys has been covered in a previous paper.1 [ ] All alloys reported were made in 15-lb. melts, superheated to 1700°F. for 15 min., cooled to 1400°F. and poured in sand molds. The test bars produced had a ½ in. reduced section and were about 6 in. long. Except for the data represented in Figs. I and 3 the alloys used were of commercial purity and contained 0.1 to 0.2 per cent Mn in addition to the aluminum and zinc. CONSTITUTIONAL DATA Under the heading of Constitutional Data are included all known data on con-

Jan 1, 1946

By Caner Zanbak, Erdogan Yüzer, Mahir Vardar, Kemal A. Erguvanli

The Hasancelebi iron deposit in Eastern Turkey is a very low grade (average 20% oxide) magnetite body consisting of 720 million longtons of proven reserve at a 10% cut-off limit. The ore-bearing scapolitic oclcs cover an area of approximately 4300m x 300m, and the thickness of the outcropping deposit exceeds 300m. Prefeasibility project studies revealed that a one degree decrease in a 45° final slope angle of the proposed pit would require excavation of approximately 10 million cubic meters of excess waste material, for a projected pit bottom 300 meters below the valley floor. There- fore, determination of the final slope angles of the open pit was considered to be the most important task in the feasibility analysis of this project. In this investigation, the main emphasis was given to collection, compilation and evaluation of the engineering geological, hydrogeological and rock mechanics data of the highly fractured and weathered rocks. Due to the presence of intense fracturing, the rock wedge analysis method was used for projected 30m-high benches and the circular failure analysis method was used for the stability of the projected final pit slopes. The proposed bench slope angles ranged between 60° and 80°, whereas the projected final slope angles varied between 30° and 48°, depending on the slope heights and groundwater levels.

Jan 1, 1983

By G. Broughton

For the past few years a great amount of work has been done on the viscosity characteristics and gelation of clay suspensions, much of which has been reported in papers published by the Institute.7,12,18,19,24 Impor-tant reviews have been made elsewhere by Evans and Reid,10 Marshall20 and Clews, Macey and Rigby,8 the last two on the general properties of clay. It is unnecessary, therefore, to recapitulate past work beyond recalling that three explanations for the high viscosity and gelation of clay suspensions have been put forward. For lack of more exact nomencla-ture, these may be called the water hull,16 mechanical interference" and attraction-repulsion" theories. The first pictures the clay particles as surrounded by relatively rigid water envelopes, which increase effective volume; the second emphasizes the mechanical interference of platy particles or their agglomerates; while in the third the particles are assumed to be held relatively rigidly at a distance from each other determined by the balance between the attractive (van der Waal's) forces and the elec-trical repulsions of the charges. 13,14 This article presents fresh data on clay suspensions, particularly on the influence of previous flow history of the suspensions, specific contra-ions, temperature, solvation and particle size, in an attempt to contribute to the solution of the problem.

Jan 1, 1938

By R. W. Raymond

In a paper on the Divining-Rod (Transactions, xi., 411), presented at the Boston meting, in February, 1883,I suggested, among other signs of which the skilled prospector might consciously or unconsciously avail himself in the search for springs of water or mineral deposits, the presence of particular grasses or shrubs, and the general appearance of the flora. There are not wanting, in the literature of our art, indications that greater attention was paid to such signs in ancient days than at present. It is the tendency of a scientific age to ignore, or regard as superstitious, what cannot be classified or explained. But the acute though unscientific observation of earlier times often, doubtless, accumulated facts which it would be worth our while to re-examine. It is highly probable that the mining prospectors of the sixteenth and seventeenth centuries, to go no further back, were close students of nature, and knew, though they could not explain, and, for reasons of private gain, would not communicate, many curious and significant facts. We can generalize better than they could; but for that very reason we are, perhaps, their inferiors in observation. They let nothing pass, because all things were equally significant to them. We take wider views, and miss more. And, no doubt, there still exists among practical millers, prospectors,, hunters, Indians, etc., an unwritten.

Jan 1, 1887

By J. N. Hummel

THE methods of electrical prospecting, which employ contact electrodes to produce an electric field in the ground, furnish information concerning the constitution of the material beneath the surface, as indicated by the distortion of this artificially produced field and anomalies therein. To reveal the distortion of such field of known character, it is only necessary to measure qualitatively the direction of the field, using sensitive compensation methods. In such a case, the survey is relatively simple, and that is an important factor from a practical point of view, The distortion of the normal field thus determined permits an easy interpretation and gives approximate information as to the subsurface conditions, without the necessity of a thorough theoretical knowledge of the electrical field. The true field of application of the equipotential lines and search-coil methods, which are based on this principle of directional determination of the electrical field in the ground, is that of search for deposits of economic minerals for the mining industry, although they can also be used in solution of other problems; for example, in the determination of the strike of anisotropic beds. The distortion of the electric field as represented by the picture of equipotential lines or other measured curves is striking only when bodies having conductivities different from that of the country rock are embedded in the underground, or when the underground is anisotropic.

Jan 1, 1931

By James S. Browning

The Bureau of Mines conducted laboratory and small-scale continuous tests of kyanite ore from Georgia and South Carolina to determine the technical feasibility of recovering commercial grade kyanite concentrates by flotation. The research indicated that combinations if sulfuric acid and petroleum sulfonate may be used effectively for flotation of kyanite from quartzite-kyanite ore. This report summarizes the results of these tests, and demonstrates the feasibility of producing commercial-grade concentrates with a high recovery of the contained kyanite. Extensive deposits of kyanite occur in the southeastern United States. The reserves of these deposits, if developed, are adequate to supply the United States with 35-mesh kyanite concentrate for many years at the present rate of consumption. According to Espenshade and Potter,' the kyanite-quartz rock type deposits in this area contain about 100 million tons of ore averaging 10 to 30% kyanite. The tonnage of kyanite-bearing gneiss and schist is much larger than the tonnage of kyanite-quartz rock, but the kyanite gneiss and schist are appreciably lower in grade. The largest deposits of kyanite-quartz rock are in the Farmville district, Virginia, and Kings Mountain district, North Carolina-South Carolina, and at Graves Mountain, Ga. Of the known deposits, only four were being mined for kyanite in 1 967. These deposits are near Farmville and Dillwyn, Va., Clover, S.C., and Washington, Ga.

Jan 1, 1970

By Sidney H. Loram

As the work carried on by this Company, of which the writer has been in charge for the past two years, is somewhat unique, the following account of it may be of interest, and, on that account, is offered to the Institute without any attempt to claim this practice as the best. Mines. The mines supplying ore to the Company arc situated in three groups: the Guanaco field,.about 80 miles N.E. of the port of Taltal (lat. 25" S., long. 70" 30' W. of Greenwich); the Sierra Overa, about 63 miles S.W. of Taltal; and Paranao, about 42 miles due N. of Taltal (12 miles N. of the small town of Paposo, once famous for its copper-output). Guanaco. This field lies in the center of an absolutely waterless mountainous desert, where not a sign of vegetation can be found for miles. The dryness is such that ivory and horn crack and open, while raw-hide must be used in place of leather, which -would become worthless in a very short time. Water is brought about 21 miles by piping from the Cordillera, but only in small quantities, and costs in the Guanaco $7 (= $1.78 gold) per cubic meter. All supplies and food are sent from the port of Taltal, which in turn draws its supplies from the south of Chile, the

Jan 1, 1900

By Milton E. Wadsworth, J. Brent Hiskey

INTRODUCTION Fifteen years ago a distinguished electrochemist referred to electrochemistry as an "underdeveloped science " In the article in question, Professor Bockris (1) stated that many areas of.natura1 phenomena and applied technology are not perceived as being electrochemically based At that time, this was especially true for much of non-ferrous extractive metallurgy and was a particularly accurate description of hydrometallurgy During the last decade, there has been considerable advancement in applying the theory of electrochemistry to our know1 edge of hydrometallurgical processes and in understanding the mechanisms of underlying electrode reactions. Impressive as these advances are, there is still a growing need for electrochemical research of mineral systems and electrochemical engineering to apply this work in practical situations In a broad sense electrochemistry is defined as the physical chemistry of ions in solution and of phenomena which occur at the electrified interface. Bockris and Reddy (2) refer to electrochemistry as being divided into two fundamental domains, ionics and electrodics ionics is restricted to the behavior of ions in solutions, examples being many familiar redox processes Electrodics represents the main part of electrochemistry, and is the study of charged interfaces and the conditions governing charge transfer reactions across them. Considering hydrometallurgical applications, electrodics suggests the following relationship for a conducting solid (bulk or surface)

Jan 1, 1981

By A. F. Melcher

THE present paper is a progress report. on an investigation of the physical factors of oil and gas and especially of their sands, I such as-pore space, size of pores or permeability, retentivity, viscosity of the oil, temperature, pressure, thickness and area of the pay sand, water relations, and capillarity. The purpose is to determine as many of these physical factors as possible, and to ascertain the relations existing, directly or indirectly, between these physical factors and the production of oil and gas. As yet only pore space2 and size of grains of pay sands have, been investigated, although an apparatus has been designed to determine the permeability of a sand to oil, water, or gas under definite drops of pressure between the entrance face and exit face of the sample. Messrs. E. W. Shaw, R. Van A. Mills, D. Dale Condit, G. B. Richardson, G. C. Matson, and C. H. Wegemann collected the samples upon which the physical determinations were made. Acknowledgment is made to my colleagues of the United States Geological Survey for many suggestions and criticisms; to Mr. Mills for the production data given of the oil wells from which some of the samples were collected; to Mr. A. W. McCoy of the Empire Gas and Fuel Co., Bartlesville, Okla., for many ideas.

Jan 4, 1920

By B. Egeberg

IN A previous paper1 the authors dealt with the physical properties of cold-rolled and heat-treated Britannia metal of the approximate composition Sn, 91 per cent., Sb, 7 per cent. and Cu, 2 per cent. It was found that cold rolling to more than 50 per cent. reduction produced a continuous softening of the metal when measured by the Brinell machine, whereas the Shore instrument indicated increased hardness; that the strength of the material followed the Brinell hardness and that the metal therefore became weaker the more it was cold-rolled; and further, it was found that hardness and strength could be largely restored to the cold-rolled metal by "baking" for about one hour at any temperature, between 200° and 450° F., the melting point. The higher the baking temperature, the more effective was the heat treatment as far as increased hardness was concerned. It seemed to be of little importance whether the metal was soaked or not at the baking temperature for a great length of time and the rate of cooling seemed to be immaterial. The present paper deals with the same alloy and more particularly with the resistance towards various forms of stress - tensile, bend and deep drawing. The metallography of Britannia metal has in part also been covered and an explanation attempted for the abnormal behavior of this alloy.

Jan 1, 1929

By Joel Watkins

THE terms kaolin, china clay, ball clay, and paper clay are more or less loosely and interchangeably applied to a large class of white-burning clays. These clays are made up chiefly of hydrous amorphous (colloidal) aluminum silicates with variable amounts of free silica and other impurities in small quantities. Occasionally also the term kaolinite is wrongly applied to a white-burning clay, for kaolinite, is a mineral of definite chemical composition and definite crystalline form which occurs but sparingly in nature. It is not the purpose of this paper, however, to define or classify clays, or to enter into a discussion of the chemistry of clays. It is rather a general description of the occurrence and methods of mining of a kindred group of clays, and a discussion of their future economic aspect. In the Southern Appalachian States, the mining of white-burning clays has in recent years become an important industry. Although these clays are of several distinct types, which occur in as many localities under different geologic conditions, they are for the most part. primarily of the same origin. They are essentially the same in elementary constituents, and are largely consumed in the same industrial arts. From the standpoint of a mining engineer, therefore, and for convenience in comparison and correlation, it should be interesting to discuss them under one heading.

Jan 2, 1915

By Daniel Martin

THE dendritic pattern of steels shown by deep etching is used exten-sively as a guide in the inspection and control of the great majority of steels used in ordnance construction and for many applications in indus-try. The value of macroexamination lies in the fact that it enables a qualified observer to make deductions concerning the general quality of relatively large pieces of metal. Not the least of these general character-istics is the nature and extent of the dendritic segregation in the steel, either in the cast condition or after mechanical or thermal treatments. PREVIOUS WORK Detailed methods for macroetching were outlined by Yatsevitch1 and have been standardized by the American Society for Testing Materials. A comprehensive study of the occurrence, origin, and the chemical and crystalline nature of the dendritic structure was given by Keshian.2 The marked persistence of dendritic segregation in nickel steels is fully recognized and has been discussed by Sauveur and Reed' and by others. Very little, however, has been written on the effect of the various elements on the macrostructure of steels, and the purpose of this report is to submit evidence concerning the influence of chromium, nickel and molybdenum on the macrostructure of some 4 by 4-in. ingots cast and treated under closely controlled conditions.

Jan 1, 1939

By R. S. Archer

BERYLLIUM has certain properties such as low density, high hardness, good corrosion resistance, low thermal expansion and fairly good electrical conductivity, which would indicate that it, is worthy of consideration as an ingredient of light alloys. It was not until recently, however, that beryllium could be produced with sufficient ease to encourage research along this line. The production of beryllium by electrolysis from a fluoride bath has now developed to the stage where it could be used commercially if there were sufficient demand for the element. Claims made in certain newspapers and technical articles in regard to the strength and corrosion resistance of the aluminum-beryllium alloys are not justified by experimental results. Moreover, beryllium is an expensive metal ($200 a pound at the time this work was done) and, on account of the nature of its ore and the consequent difficulty of its extraction, it will in all probability continue to be a relatively expensive metal, although the cost would undoubtedly be a great deal less than $200 a pound if the metal were produced on a large scale. It seemed, therefore, that low-beryllium alloys offered the greater commercial possibilities except for very special purposes. It was partly for this reason that in the present work emphasis has been placed on beryllium alloys of low beryllium content.

Jan 1, 1928