Search Documents

By D. Harrington

As no cure is known for silicocis after it has developed, prevention is the only effective remedy. There are two main lines of approach to the problem of dust-disease prevention in industry - the engineering, through control of dust production, and the medical, through selection of workers by examination; success probably depends upon a combination of the two. Hatch (146) considers the following measures essential to a complete, well-balanced program of control of the dust hazard in industry: 1. Selection of workers by means of physical examinations in order especially to eliminate those with tuberculosis and other disorders of the respiratory system. 2. Reduction of the duct concentration below the standard of permissible dustiness through adequate moans of dust control and good housekeeping. 3. Limiting the frequency and duration of employment in the dusty occupations, thus reducing the rate of deposition of dust in the lungs. 4. Routine measurement of the effectiveness of the dust-control program by means of periodic medical examinations and duct surveys.

Jan 1, 1935

By E. D. Gardner

This paper discusses prospecting for lode gold and lists the principal lags and. regulations pertaining to locating; lode claims on public lands. It is a preprint of a part of a bulletin being prepared by the United States Bureau o Mines entitled "Equipping, Developing and Operating Small Gold Mines". The increased interest in gold mining manifested during the past few years (1932-1935) bas stimulated prospecting. Many adventurers have taken to the field to search for now gold deposits. A. large percentage of them have had no previous experience in prospecting for lode gold; this paper has been written with the tope that it might assist these newcomers.

Jan 1, 1935

By E. C. Lane

During the past 15 years the Bureau of Mines has made and published several hundred analyses of typical petroleums and has developed a system of interpreting the analyses and of classifying crude oils. In describing crude petroleum frequent reference is made to the "base" of the oil, a usage the petroleum industry has found convenient. As part of its general study of the characteristics of crude oils, therefore, the Bureau of Mines has developed a system of classifying them according to "base." This system as first published in 1927 was limited to four classes and in its original form is no longer considered adequate. Since the system was first published the Bureau has analyzed a large number of crude oil, including representative samples from nearly every important producing field in the world, and has found that the system of classification could be revised and amplified to advantage. The revised system is presented herein.

Jan 1, 1935

By E. C. Lane

During the past 15 years the Bureau of Mines has made and published several hundred analyses of typical petroleums and has developed a system of interpreting the analyses and of classifying crude oils. In describing crude petroleum frequent reference is made to the "base" of the oil, a usage the petroleum industry has found convenient. As part of its general study of the characteristics of crude oils, therefore, the Bureau of Mines has developed a system of classifying them according to "base." This system as first published in 19274 was limited to four classes and in its original form is no longer considered adequate. Since the system was first published the Bureau has analyzed a large number of crude oil-, including representative samples from nearly every important producing field in the world, and has found that the system of classification could be revised and amplified to advantage. The revised system is presented herein. Bulletin 2916 states that many oil producers and refiners use the word "base" much as it is used in pharmaceutical work. For example, the "base" or "basis" of an ointment or salve is the fatty material (lard, petroleum, or lanolin) used as a vehicle or carrier for the active medicinal principles. Apparently many of the pioneers in the petroleum industry considered crude oil similar in nature to these medicinal products in that it consists of a semisolid, nonvolatile base and 1 volatile portion can be distilled off to make gasoline, kerosene, and other products. Many crude oils when chilled slowly deposit a waxy material (paraffin); this fact may have been one reason for the use of the term "paraffin base" in referring to such oils. Almost all of the petroleum first discovered in the United States was of this nature; not until the oil industry was extended to California and along the Gulf coast was petroleum found that contained no wax but apparently did contain asphaltic material Accordingly, these oils were known as "asphalt-base" oils. The use of this term, however, seems unfortunate, as better-grade oils of this type contain little if any asphalt; the descriptive term "naphthene base" now seems to be a more desirable term than "asphalt base." The term "intermediate base" is also used commonly in referring to oils intermediate in oharacteristios between those of paraffin and naphthene base.

Jan 1, 1935

By A. U. Seybolt, C. H. Mathewson

As is well known, many questions affecting the properties and uses of a metal cannot be answered without careful consideration of the state of purity realized in the various operations of preparation, refining, or special treatment that have brought the product to its final state. The occurrellce of an impurity in minute quantity offers no guarantee that its effect will be inconsiderable because dissolved substances often modify the properties of a metal quite out of proportion to their concentration. In such cases the determination of solid solubility must be accepted as a problem of considerable difficulty, requiring the use of especially purified materials and methods not ordinarily used in the metallurgical laboratory. This aspect of the equilibrium between metals and their oxides is especially important and a search for fundamental data reveals little except conflicting opinion even concerning the systems of common occurrence and interest. Rhines and Mathewson1 in 1934 studied the solubility of oxygen in solid copper by annealing to equilibrium in air and gave reasons for the failure of other methods, notably the ordinary procedure of heat-treatment followed by microscopic examination, to yield reliable results. In this paper, a similar study has been made of the solubility of oxygen in cobalt. The simple theory of this method is outlined below. Conditions of Equilibrium between a Metal and Dissolved Oxide at Different Temperatures and Pressures The general conditions of equilibrium in any system are conveniently summarized in a projection of the triple curves of the P, T, X space

Jan 1, 1935

By J. A. Taylor, H. F. Yancey

"INTRODUCTION Froth flotation as applied to coal is a process for separating desirable carbonaceous material from undesirable inorganic matter. In general, the feed must be finer than one eighth inch in size. The principal use of the process in the preparation of coal appears to be in the treatment of the fine sizes produced by breakage during mining and preparation.The Bureau of Vines in Information Circular 6714 has published general information on coal flotation, summarized investigative studies of the process, and described operating plants throughout the world with their tonnage, reagent consumption and operating costs.4ACKNOWLEDGMENTSThe present study of means for depressing pyrite and reducing ash ty froth flotation was conducted at the Northwest Experiment Station of the United States Bureau of Wines in cooperation with the College of vines. University of Washington, under the general direction of A. C. Fieldner, chief engineer, Experiment Stations Division, Bureau of Wines. Grateful acknowledgment is made for suggestions and criticisms received from W. H. Coghill, supervising engineer, U.S. Bureau of Mines Mississippi Valley Experiment Station, Rolla, Mo.; J. B. Morrow, and R. E. Zimmerman, of the Pittsburgh Coal Co.; and Dean Milnor Roberts and Prof. Joseph Daniels, of the College of Mines, University of Washington.FLOTATION AND DEPRESSIONA substance will tend to float if its surface attracts a gas film more strongly than it does a liquid film when both air and liquid are competing for this attraction. On the other hand, a substance will not float if its surface attracts a liquid film more strongly than it does a gas film. All theories of depression depend upon this fact. A wetted particle of floatable size most likely will be found in the tailings after the flotation process has been completed.The crux of flotation is the selective wetting of the undesirable material that tends to float. Two general methods 5, 6, 7 of depression are in use: One combines a chemical substance with the surface to form a wettable compound, and the other employs some colloidal or ionic substance which the surface selectively adsorbs, thereby forming a wettable surface."

Jan 1, 1935

By J. E. Pollock, W. R. Hicks, E. Camp

IN the oil-refining industry, steel comprises by far the greatest proportion of the materials used in construction work, but with an enormous number of alloy steels and nonferrous alloys available, and a greater knowledge of their properties and corrosion resistance, a substitution first in the "hot spots" and then in locations of moderately severe corrosive conditions will be made as the greater expense can be justified. In new construction work, advantage is taken of the experience already gained and appropriate materials used, whether for high temperatures and pressures demanding additional strength or for corrosive conditions. The locations, however, where equipment in operation constantly requires replacement will soon become evident, as will the necessity for replacement in more resistant materials, if considerable down-time is to be avoided. In what direction and how far to go in the matter of alloys then becomes a question of the highest importance. Obviously, any replacement with more costly material must be justified economically by the promise of longer life, thereby saving both material and installation costs besides the reduction of loss of production. Where the equipment is overcapacity and a regular schedule of cleaning periods is in force, the last item frequently must be ruled out and justification made on the basis of the first two only. Installation of material that will outlast the remainder of the equipment and have no recovery value must also be avoided; this is particularly important in temporary construction or in old equipment that will soon become obsolete. TEST METHODS Either one Of two methods or a combination of both, in the absence of reliable data in similar services, may be adopted to determine to what extent replacement with other, and perhaps more expensive, materials is justified. A unit may be constructed incorporating different metals or alloys so that comparative service may be obtained under the same service conditions; this has been applied in many instances, such as condenser and tank construction, but the opportunities for inspection may be few and

Jan 1, 1935

By John Gross

The study of the energy used in crushing operations has advanced from a period of perplexing confusion to one of greater clarity. Only within the last few years has any true conception of the work in crushing been possible, owing to the chaotic state of theoretical knowledge. For some 20 years a controversy existed between those advocating the Rittinger law and those advocating the Kick law. The Kick law now appears to be definitely out of the picture, and crushing efficiency may be based confidently on the Rittinger theory. There also seems to be a generally crystallized conception as to the meaning and nature of sub-sieve material. There is needed a simple, direct method for determining surface on a crushed ore product, and also a simple and accepted method for size determination on minus 400-mesh material. The Crushing Law The Rittinger(l)‡ theory of crushing was advanced in 1867 and the Kick(3) theory in 1885. While the Rittinger theory might have been accepted without much question and actually had been accepted by many investigators, a serious doubt as to its validity was raised by Stadler(10) who upon purely theoretical grounds proclaimed the Kick "law" as the true law of crushing. According to Rittinger the energy required in successive steps in reduction increases geometrically, while according to Kick the energy increases arithmetically. These "laws" therefore are at variance, and the establishment of the true law was recognized as of first importance. Many simple experiments have been made to demonstrate the application of the Rittinger theory to crushing, and it would seem that its simplicity should favor its acceptance. Experimental evidence, however, was not convincing, as no reliable data could be obtained on the finer material from a crushing or grinding operation. Gates,(13) Bell,(19)

Jan 1, 1935

By A. U. Seybolt, C. H. Mathewson

As is well known, many questions affecting the properties and uses of a metal cannot be answered without careful consideration of the state of purity realized in the various operations of preparation, refining, or special treatment that have brought the product to its final state. The occurrence of an impurity in minute quantity offers no guarantee that its effect will be inconsiderable because dissolved substances often modify the properties of a metal quite out of proportion to their concentration. In such cases the determination of solid solubility must be accepted as a problem of considerable difficulty, requiring the use of especially purified materials and methods not ordinarily used in the metallurgical laboratory. This aspect of the equilibrium between metals and their oxides is especially important and a search for fundamental data reveals little except conflicting opinion even concerning the systems of common occurrence and interest. Rhines and Mathewson1 in 1934 studied the solubility of oxygen in solid copper by annealing to equilibrium in air and gave reasons for the failure of other methods, notably the ordinary procedure of heat-treatment followed by microscopic examination, to yield reliable results. In this paper, a similar study has been made of the solubility of oxygen in cobalt. The simple theory of this method is outlined below.

Jan 1, 1935

By John Chipman

RECENT developments in iron alloys containing nitrogen have indi-cated that this element may exert a considerable influence on the proper-ties of the metal. This influence is not always in an undesirable direction and the indications are that nitrogen should be regarded as an alloying element, the amount of which should be subject to control, rather than as an inherently deleterious impurity. In controlling this element in liquid iron to the best advantage, it is necessary to have a reliable background of fundamental data pertaining to solubilities, rates of solution and chemical reactions of nitrogen in liquid iron. Obviously, the first step in such an investigation is the determination of the solubility of nitrogen in pure iron, and this has been the object of the experiments described in this paper. The solubility of nitrogen in solid iron has been measured by Jurich,1 Sieverts,2 Martin,3 and Iwasé4 and the agreement among the first three inspires confidence in their results. No accurate determinations of its solubility in liquid iron have been recorded though several investigators have obtained approximate results. Strauss5 was able to introduce 0.03 to 0.04 per cent nitrogen into steel by the action of either ammonia or nitrogen on the liquid metal. This was accomplished by Eilender and

Jan 1, 1935

By J. E. Pollock, W. R. Hicks, E. Camp

In the oil-refining industry, steel comprises by far the greatest proportion of the materials used in construction work, but with an enormous number of alloy steels and nonferrous alloys available, and a greater knowledge of their properties and corrosion resistance, a substitution first in the "hot spots" and then in locations of moderately severe corrosive conditions will be made as the greater expense can be justified. In new construction work, advantage is taken of the experience already gained and appropriate materials used, whether for high temperatures and pressures demanding additional strength or for corrosive conditions. The locations, however, where equipment in operation constantly requires replacement will soon become evident, as will the necessity for replacement in more resistant materials, if considerable down-time is to be avoided. In what direction and how far to go in the matter of alloys then becomes a question of the highest importance. Obviously, any replacement with more costly material must be justified economically by the promise of longer life, thereby saving both material and installation costs besides the reduction of loss of production. Where the equipment is overcapacity and a regular schedule of cleaning periods is in force, the last item frequently must be ruled out and justification made on the basis of the first two only. Installation of material that will outlast the remainder of the equipment and have no recovery value must also be avoided; this is particularly important in temporary construction or in old equipment that will soon become obsolete. Test Methods Either one of two methods or a combination of both, in the absence of reliable data in similar services, may be adopted to determine to what extent replacement with other, and perhaps more expensive, materials is justified. A unit may be constructed incorporating different metals or alloys so that comparative service may be obtained under the same service conditions; this has been applied in many instances, such as condenser and tank construction, but the opportunities for inspection may be few and

Jan 1, 1935

By D. Harrington

Hatch (260) made the following pertinent statement regarding the present status of engineering design of dust-control equipment: Textbooks on ventilation and engineering handbooks devote little or no space to methods of control of industrial dust, and in the technical journals papers on fundamental engineering design of equipment are conspicuous by their absence. In a recent bibliography of the literature on pneumoconiosis less than 1 percent of the articles dealt with the engineering control of the disease. The science of dust control has not developed beyond the stage of trial and error, and the design of structures for the suppression of dust is based almost entirely upon empirical data together with one or two elementary formulas. The latter were derived from the generalized experience in a limited number of Industries such as woodworking, where conditions and requirements are not at all like those, for example, in a sand-pulverizing plant. Wide experience and good judgment are essential to the proper use of the scanty information that has been collected and systematized. Without attempting to minimize the importance of experience in engineering design, it is necessary to point out that most of the past experience obtained in the empirical design of dust-control equipment was not evaluated by means of quantitative studies of the actual reduction in dust , fence, past experience does not necessarily furnish the proper guide for future design. In fact, recent surveys in certain industries, employing modern methods of investigation, have shown that existing equipment is in many cases inadequate.

Jan 1, 1935

By Harry T. Davis, Jasper L. Stuckley

The object of this paper is to record and interpret field and laboratory observations made by the writers during five years of study of the barite deposits of North Carolina. Deposits of barite are known to occur in three localities in North Carolina (Fig. 1) two of which—the Hot Springs and Kings Mountain —contain material of economic value. The Hot Springs area begins near Bluff, some 6 miles south of Hot Springs, and continues northeast by Stackhouse; a total length of 7 miles. The Kings Mountain deposits lie along a belt that extends from the north end of Crowders Mountain in a southwestward direction, along the east side of this and Kings Mountain, to Kings Creek, South Carolina. The third locality is 3½ miles southeast of Hillsboro, Orange County, a short distance west of the highway leading from Hillsboro to Chapel Hill. It is not known when barite was first discovered in North Carolina, but production from the Hot Springs area began some 50 years ago. The state has never produced large quantities of barite—usually there have been less than three producers—and definite figures are not available, but reasonably reliable estimates indicate a total production of 300,000 tons. From 1901 through 1920 barite mining was on a seemingly prosperous basis and a large tonnage was shipped from the Hot Springs and Kings Mountain areas. With the depression of 1920 the industry began to decline and production practically ceased in 1926. Geology of the Barite Areas In the Hot Springs area barite is found in the Max Patch granite of Archean age and the Snowbird formation of Cambrian age. The Max Patch granite is of two varieties, one gray to whitish and the other red. The gray granite is coarse, at times porphyritic, and composed of quartz, orthoclase and plagioclase feldspar, with a little biotite and muscovite. The red granite is also coarse and differs from the other only in having conspicuous pink and red feldspar. Both varieties have been much metamorphosed and weathered in places, so that they contain secondary

Jan 1, 1935

By James P. Sloss

WHAT is the likelihood if any-that a real gold mining industry will be developed in the southern Appalachian region? Has the increase in the dollar value of gold from $20.67 to $35 per ounce potency to turn the trick? Suppose it be assumed that the price of gold will, at worst, not recede, and that the cost of digging ore and treating it of which the average level of commodity prices and wages is a fair index-will, at most, not exceed that prevailing in 1926. One may or may not accept these as reasonable assumptions; but one must arbitrarily remove some of the potential variables if one is to get anywhere on a problem like this. As a matter of fact, this article is not going to venture a conclusive answer to the question that has been posed; but it will endeavor to present some of the factors that have a bearing on the problem. The writer spent ten days visiting a dozen properties in Virginia and the Carolinas early in April, 1935, and in doing so got a first-hand slant on mining conditions in the domain of King Cotton.

Jan 1, 1935

By LESTER W. STRAUSS

FOR fifteen months after the other dominions of the British Empire and the entire so-called sterling 11loc loosed the shackles that bound the111 to the gold standard, South Africa, giant among gold-producing nations, remained stubbornly attached to gold at the traditional ratio of 85 shillings in currency to one ounce of gold. But eventually even South Africa had to heed the dictates of trade and the obvious interests of its great gold-mining industry. In December, 1932, South Africa's currency severed its golden bonds. Today the South African pound is 011 a par wit11 the British pound.

Jan 1, 1935

By P. P. Gregory

ESTIMATION of re- serves in prorated sand fields has been discussed by S. A. Judson, H. D. Easton, Jr., and W. A. Schaeffer, Jr., in a paper that appears in Vol. 114 (1935), of the A.I.M.E. TRANSACTIONS. The purpose of this present paper is to extend the investigation to prorated flush limestone fields and to outline a method of procedure in determining the amount of oil originally in place and the amount of oil that can be recovered from such fields. Although it is possible to use the decline curves to estimate the amount of recoverable oil in certain limestone fields that are allowed to produce the oil at or near capacity production, such a method cannot be used in fields under severely restricted production rates. The problem is exceedingly complex due to fluctuation in the allowable rates of oil production over a wide range and at frequent intervals, and especially because of the heterogeneous nature of the reservoir itself. A well completed in a large solution cavity, capable of producing great quantities of oil per day, may be offset by a well of very limited capacity. Also, it is di5cult to arrive at an average figure for porosity in a given limestone reservoir due to abrupt variations in the character of limestone, in many instances even between two ad- joining wells. It is a safe statement that uniformity of porosity and permeability in limestone reservoirs .is nonexistent. It is evident, therefore, that the method of estimation of re- serves on the basis of per-acre content can give only approximate results.

Jan 1, 1935

By Sherwin F. Kelly

NEW trend in geophysics has been uncovered in these depression years, made evident through the thinning cloak of commercial activity, which, in better times, would have completely obscured it. I refer to the increasing use of these methods for geological investigations by federal and state geological surveys. This is a trend that has been gathering momentum not alone in the United States, but abroad as well. Thus, in Poland, the Geological Survey has been playing an increasing role in geophysical work since 1927, and now has- its own geophysical department. The government petroleum producing organization of Argentina has its Geophysical Commission; Brasil boasts a completely equipped geophysical department in its Mineral Production Service; the government of Chile has contracted with commercial companies for geophysical surveys; Peru is planning an intensive program of geophysical prospecting in its petroliferous regions; and Canada has, for several years, cooperated with

Jan 1, 1935

By E. C. Truesdale

IN recent years various problems in connection with research work on the preparation and properties of zinc-base alloys have required reliable information concerning the constitution of the zinc-rich portion of the iron-zinc equilibrium diagram. On numerous occasions rather positive indications were obtained that, for example, the solubility of iron in zinc was incorrectly represented on the current equilibrium diagrams. A careful study of all the available literature relating to the iron-zinc system led to the conclusion that much of the early work was unsatisfactory as measured by present standards of experimental accuracy, and as a result it was decided to redetermine the location of the liquidus curve and of adjacent portions of the diagram. Part I of this paper comprises a description of the experimental methods and a summary of the results by means of which the zinc-rich end of the iron-zinc diagram has been revised in the following ways: 1. Measurements of the solubility of iron in liquid zinc by several different sampling methods, leading to a relocation of the liquidus curve. 2. Microscopic, conductivity, and X-ray studies of the solid solubility of iron in zinc, which, together with thermal analyses, have resulted in new values for the solid solubility and the eutectic temperature and composition. 3. Heating and cooling curves, obtained by a refined differential method, leading to new locations for the two peritectic horizontals. In Part II of the paper the attempt is made to review all of the pub-lished work having a bearing on the constitution of the iron-zinc system, and to correlate the present results, and some recently published data

Jan 1, 1935

By James Aston

A PROPER consideration of this subject is not confined to the technical channels of production and metallurgy. It concerns an industry, and should cover economic aspects which are of material importance in any program of development. The discussion may logically be treated under three subdivisions, as follows: (1) manufacture, (2) characteristics related to quality of material; (3) adaptability and exploitation of product. MANUFACTURE OF WROUGHT IRON The manufacture of wrought iron is the most ancient art of the ferrous metal industry. The eighty years or less of existence of processes identified with our modern "Age of Steel" is a relatively brief interval compared with the several thousand years associated with the production of wrought iron by man. From the primitive early methods of production, manufacture for many centuries followed the line of direct reduction. There were developments as experience was gained through the years; but man's needs for a strong, ductile, forgeable product were met by reducing the ore to metallic iron in a single-stage operation. Following the development several centuries ago of what has become our modern blast-furnace operation, manufacture of wrought iron was gradually transformed into a two-stage method of first producing cast iron and then refining this to the desired degree of forgeability; the forerunner in principle of today's scheme of manufacture of steel. The product retained the essential characteristics of highly refined base metal with iron-silicate slag incorporation, which were associated with the material resulting from direct reduction methods. Cort's invention of the puddling process in 1784 is a landmark in wrought-iron manufacture. It consisted essentially in adapting a coal-fired reverberatory furnace to the refining operation; thus lifting the industry out of the slough of

Jan 1, 1935

By James Aston

A PROPER consideration of this subject is not confined to the technical channels of production and metallurgy. It concerns an industry, and should cover economic aspects which are of material importance in any program of development. The discussion may logically be treated under three subdivisions, as follows: (1) manufacture, (2) characteristics related to quality of material; (3) adaptability and exploitation of product. MANUFACTURE OF WROUGHT IRON The manufacture of wrought iron is the most ancient art of the ferrous metal industry. The eighty years or less of existence of processes identi-fied with our modern "Age of Steel" is a relatively brief interval com-pared with the several thousand years associated with the production of wrought iron by man. From the primitive early methods of production, manufacture for many centuries followed the line of direct reduction. There were developments as experience was gained through the years; but man's needs for a strong, ductile, forgeable product were met by reducing the ore to metallic iron in a single-stage operation. Following the development several centuries ago of what has become our modern blast-furnace operation, manufacture of wrought iron was gradually transformed into a two-stage method of first producing cast iron and then refining this to the desired degree of forgeability; the fore-runner in principle of today's scheme of manufacture of steel. The product retained the essential characteristics of highly refined base metal with iron-silicate slag incorporation, which were associated with the material resulting from direct reduction methods. Cort's invention of the puddling process in 1784 is a landmark in wrought-iron manufacture. It consisted essentially in adapting a coal-fired reverberatory furnace to the refining operation; thus lifting the industry out of the slough of

Jan 1, 1935