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By William H. Morris

At the Glen Summit meeting, the question of controlling the silicon in pig-iron WAS raised; and as this has been deemed by most furnace-men for years past a matter of special difficulty, an account of our experience in the matter may be of interest. When running on mill-iron, some years ago, we aimed to keep

Jan 1, 1893

By R. A. Swalin, A. H. Geisler

THIS study represents an investigation of the effect of annealing temperature on the texture of drawn molybdenum, iron, and an iron alloy containing 14 pct Al. The effect of temperature on annealing textures has not been widely investigated in the past. One of the obstacles in making such a study using usual X-ray diffraction techniques results from the

Jan 1, 1957

By H. Reinhardt, P. Haglund, J. Rydberg, B. Lunden

As legislation to minimize pollution in effluent streams becomes stricter, it is important to treat used acid pickling baths before discharge. This is usually achieved by neutralization of the acids and precipitation of the dissolved metals in such a way that neither acids nor metals can be re-used. A process has been designed and tested on a pilot plant scale to recover both acids and metals from a stainless steel pickling bath leaving only Na2SOs in the effluent. In this process, H2SOr is added to the spent pickling liquor and the recovery of the pickling acids HN03 and HF is achieved by solvent extraction, using TBP in kerosene as the organic solvent. The extracted acids are stripped with water, giving an acid concentration high enough for direct use in the pickling bath. Molybdenum is also extracted by TBP and is recovered in a separate step. The other metals, Fe, Cr and Ni, are precipitated from the raffinate as hydroxides, dried and recycled to the metal process. In evaluating this process, comparative experiments with mixer-settler and pulsed column have been performed. The process described is being considered for use by a Swedish company pickling 70,000 tons per annum of stainless steel.

Jan 1, 1973

By Daryl R. Tweeton, Jerry R. Riding, Grant Buma, Frank J. Rosswog

In situ solution mining of uranium has environmental advantages over conventional mining. The leaching of uranium, however, alters the ground-water quality in the aquifer where the mining occurs. Currently, regulations require that the ground water be restored to approximately its original condition. This paper, a summary of a study funded by the Bureau of Mines, reviews the state of the art in restoring ground-water quality after in situ uranium leaching. Current restoration practices discussed include disposal of liquid wastes in deep disposal wells and evaporation ponds, producing from all wells during restoration, and recirculating water purified in surface plants. Methods for predicting the effectiveness and cost of current techniques are presented. Possible alternative techniques are also described. Two restoration operations are discussed.

Jan 1, 1979

By John Devine

DURING the past few years the Bureau of Mines has been studying hydrogen-sulfide corrosion in the petroleum and natural-gas industries. Early work was confined to investigating the various practical, or operat-ing, factors that control the corrosion reaction when ordinary mild steel is being attacked. In that work it was shown that, if the optimum operating conditions1 are obtainable, . gas containing hydrogen sulfide can be handled at ordinary temperatures without serious corrosion resulting. However, frequently "sour" gas must be handled under other than optimum operating conditions, and combating corrosion then becomes a problem to be considered more during the construction of a system than during its subsequent operation. That is, where economi-cally practicable in such cases the designer will seek to substitute for mild steel other steels or ferrous metals more resistant to corrosion by hydro-gen sulfide. The comparative resistance of various commercial steels and alloy steels to corrosion by hydrogen sulfide at elevated temperatures has been reported systematically by previous investigators,2 but similar information for corrosion at ordinary temperatures is available only from scattered sources, representing different methods of testing. As the value of comparative corrosion tests depends largely upon the use of a

Jan 1, 1934

By H. F. Yancey

AT the annual meeting of this Institute held two years ago a new method, of estimating the grindability of coal was described, based on experimental work carried on by the Bureau of Mines at its Northwest Experiment Station. Since that time, several organizations concerned with the testing or utilization of coal as pulverized fuel have adopted and used the method in determining the grindability of several hundred samples of coal. In addition, a series of comparative tests of this method and three others has been carried out in five laboratories under the auspices of Committee D-5 of the American Society for Testing Materials. As a result the Committee has recommended that the Bureau of Mines method, designated as the "ball-mill method," and the Hardgrove method2, previously advanced, be accepted as tentative standards3. Since the ball-mill method was originally developed and published, an opportunity has been presented to apply it to a larger number of coals and to study intensively some of the principles upon which the method is based. This paper presents a resume of these further studies and includes a comparison with the Hardgrove-machine method. Trial runs were also made with another procedure recently proposed-the C.I.T. roll-test method4.

Jan 1, 1936

By A. Aly Selim, Bruce D. Hanson

A computer model capable of simulating the basic production system in a variety of underground mining methods has been developed at the U.S. Bureau of Mines Twin Cities Mining Research Center. The simulation of the basic production system at the working face, which includes drilling, blasting, mucking, and roof bolting, is described in this paper. The model is event-oriented; that is, the status of the system is updated at the occurrence of an event. All event or activity times, including failure and repair of equipment, are treated as stochastic variables. A location dimension, in addition to the time dimension, is used, allowing the simulation of systems with a number of stopes or faces. To aid the user in determining the efficiency of his system, the model provides several reports. An event or activity report gives the frequency of occurrence, total active time, and cumulative delay statistics for each event. An equipment report delineates the availability and utilization of all equipment. A production report provides information on various performance measures such as tons produced and holes drilled. The cost report gives the cost of various elements in the system. Operating data from an actual mining situation were used in validating the model. In addition to the description of the model, examples of simulation experiments which were performed on a room-and-pillar mine system are given. Use of the model to determine methods for improving the efficiency of the system is discussed.

Jan 1, 1976

By R. F. Hollis, C. K. McArthur

PRIOR to the application of anion exchange, all recovery of uranium from acid leach liquors precipitated an impure product requiring further upgrading before it could be refined. The ion exchange process, on the other hand, provides excellent selectivity for extracting soluble uranium from leach liquors, so that high grade concentrates can be produced directly. The discovery that uranium is readily adsorbed by anion exchange resins, together with the experience of resin and equipment manufacturers in water treatment, led to rapid development of ion exchange in a multiple column operation. Many processing plants using fixed bed ion exchange are in operation or under construction in Africa, Australia, and Canada. There are a limited number in the U. S. Although the fixed bed process has been highly successful, the feed to the ion exchange columns must be a clear solution, which is obtained by filtration or by countercurrent decantation of leached pulps. With some ores, poor filtration or settling characteristics make production of a clear solution difficult. Most processing plants in the U. S. receive their ores from a number of small mines, and there is considerable variation in the settling and filtering behavior of the ores. An ion exchange process was therefore desirable in which the uranium could be recovered directly for the leached pulp by adding ion exchange resin, which could be then separated from the pulp by a screening operation. The process would thus resemble the cyanide-charcoal process in which gold is adsorbed from cyanide pulp by means of activated charcoal. Preliminary tests in which leached pulps were directly contacted with resin beads led to the development of the RIP process.

Jan 4, 1957

By Aureal T. Cross

THIS paper is a review of the published literature on research in coal geology, principally exclusive of resource studies, which appeared or became available during 1950 and the latter part of 1949. This report is not to be construed as being complete. The papers referred to in the bibliography are those among many more, which were read either in full or in abstract. Undoubtedly other papers were published' which either escaped the author's notice or were not available to him. Those which were seen in abstract only (about one fourth of those listed) were not available in time for the inclusion of more than a notice. An outline of all papers listed in the bibliography has been arranged by subjects and reasonable subdivisions with some papers cited under more than one subject. Most papers are indexed according to the principal subject of discussion or research only as to an unusual or noteworthy section of the entire report. There will likely be some disagreement as to the quality or merit of some of the papers selected and the specialist may be supercritical of the outline or organization of papers in his field. It may be that attention has occasionally been drawn to papers reporting old information or conclusions of questionable value. Conferences and Meetings One of the best indications of the growing interest in coal geology problems in the United States is the increasing number of times this- field has been the focus of attention at conferences and meetings. Notable among these are the joint meeting of the Society of Economic Geologists and the Geological Society of America at El Paso, November 1949, at which the principal thesis was concerned with low rank carbonaceous fuel deposits, especially of western United States. Among the papers given which are already available were those presented by Barghoorn,16 Parry,180 Roe,153 and Parks.162 At the annual meeting of the Botanical Society of America in New York, December 1949, a joint meeting of the Paleobotanical and Microbiological Sections was held for which a symposium on Microbiology in Relation to the Geologic Accumulation of Organic Complexes was 'organized. Publication of the six papers presented by Ralph G. H. Siu, Elso S. Barghoorn, Irving Breger, Claude E. ZoBell, James M. Schopf, and A. C. Thayson is anticipated. At the regular meetings of the Paleobotanical Section at the same time, several other papers of interest reported on coal ball studies, partial coalification of petrified wood, and floras. In Chicago, April 1950, a symposium on Applied Paleobotany was held by the Society of Economic Paleontologists and Mineralogists in conjunction with the American Association of Petroleum Geologists. The five papers presented at this meeting dealt with the use of Paleozoic plant microfossils for stratigraphic work, J: M. Schopf, Devonian-Mississippian fossils of the black shales, Aureal T. Cross, Mesozoic plants of stratigraphic value, Th. Just, plant microfossils of the Tertiary, L. R. Wilson, and studies of the Brandon lignite, Elso S. Barghoorn. Early publication of these in the Journal of Paleontology is expected. The Nova Scotia Research Foundation and the Nova Scotia Dept. of Mines sponsored an excellent 3-day conference in June 1950, which, dealt with several aspects of coal geology. Papers on coal classification, P. A. Hacquenbard, structure and sedimentation problems in Nova Scotia, T. B. Haites, new techniques of thermal analysis, W. L. Whitehead, geochemical investigations of Nova Scotia coals, Irving Breger, the role of fossil plant spores in coal correlation and the stratigraphy of the coal-bearing strata of the Appalachian Region, Aureal T. Cross, were given. Some discussions of these papers by those in attendance were recorded, and the entire proceedings is being prepared for publication. In September 1950, an unusual 3-day field conference was held by the Ohio and West Virginia Geological Surveys under the sponsorship of the Coal Geology Committee. This study of the stratigraphy sedimentation, and nomenclature of the Upper Pennsylvanian and Permian coal-bearing strata of southeastern Ohio, southwestern Pennsylvania, and northern West Virginia .was augmented by two discussions on associated rocks (clays and shales) and stratigraphic nomenclature at Wheeling, and Morgantown, West Va. An extensive guidebook was prepared, and transcriptions of the Morgantown meeting were made. As a follow-up of the September field conference, a round-table discussion 'was held on this general topic at a special open meeting of the Coal Research Committee in conjunction with the November meeting of the Geological Society in Washington. Short prepared statements to invite discussion were given on each of several topics by L. M. Cline, Carl O.

Jan 1, 1952

By E. S. Leaver

THE presence of soluble base metals in precious-metal ores usually precludes cyanidation as the best method of treatment. The laboratory experiments described in this paper show the possibility of cyanidation of gold-silver ores containing less than 0.5 per cent, of cyanide-soluble copper and the effect of zinc in the cyanide solution. PART I.-COPPER IN CYANIDATION The proposed process of cyanidation of precious-metal ores containing copper is based on the regeneration of about 80 per cent., of the cyanide used in the dissolution of the copper. The method of regeneration involves a combination of the sulfide and the acid precipitation of the copper and silver. The resultant solution is made alkaline with lime, and the gold is precipitated with zinc dust. Solubility of Copper Minerals in Cyanide Solution In order to determine the solubility of copper minerals, including metallic copper, under the usual conditions for cyanidation, experiments were conducted with synthetic ores. Each ore sample was prepared by mixing the particular pure copper mineral with barren sea sand. Both the mineral and sand were ground to pass 100 mesh before they were thoroughly mixed. The percentage of copper in each head sample was determined by direct assay, excepting the metallic copper sample, which was computed on weights before mixing. Table 1 gives the results.

Jan 1, 1929

The discovery of nickel at the Wallace Mine in 1846, recorded in the Report of Progress of the Geological Survey of Canada, 1.848-49, was not the first find in the Sudbury mining district. As long ago as 1770 a company had been formed to work the rich deposits of, copper whose existence was then known. .But it was during the first mentioned year that, incited thereto by fresh finds and a favorable report by Mr. W. E. Logan, then Provincial Geologist, two [ ] groups of Canadians organized "The Montreal Mining Company and "The Upper Canada Mining Company." By the former company the Bruce Mines Location' was purchased and work was immediately commenced upon it. The Wallace Mine acquired by the Upper Canada Mining Company, was abandoned after a shaft had been sunk and a few test pits opened.

Jan 1, 1907

By Arthur F. Colombo, Donald W. Frommer

With the opening of the Tilden mine near Ishpeming, MI, a new era in iron ore beneficiation was begun. A description of a U. S. Bureau of Mines investigation is summarized to illustrate the selective flocculation-deslime-flotation process developed by the Bureau and used at the Tilden concentrator, which is also briefly described. The operating parameters for the selective flocculation-cationic flotation of an oxidized taconite from the Mesabi range are discussed. A water reclamation system using lime and a cationic flocculant was applied to reclaim the effluents from a 900-pound-per-hour flotation pilot plant. About 80 percent of water requirements were recovered, and the calcium content of the reclaimed water was found to be more important than clarity in influencing the selective flocculation and flotation processes. Although reclaimed waters with about 10 ppm calcium registered turbidities of approximately 5,000 ppm SiO2 equivalents, the concentrates produced using these waters contained 64 percent Fe and 55.0 percent SiO2 and had accompanying iron recoveries of 75 percent. Lower grade concentrates resulted from using reclaimed water with higher calcium contents and lower turbidities.

Jan 1, 1976

By Joseph Kaye Wood

A metal is said to be overstrained when it is deformed beyond the elastic limit at a temperature well below the critical range, as in cold working. Quantitatively, overstrain might be considered as that part of the total elastic deformation of the piece of metal, left over after the external load is removed, that added to the permanent deformation due to plastic action will give the total permanent deformation. Ordinarily the effects of this phenomenon, which vary with the internal residual stress probably in accordance with Hooke's law, are more noticeable when the yield point of the metal is exceeded, but they probably also exist to a smaller degree when the load is just large enough to cause the least amount of permanent set. These effects, which we recognize as the result of overstrain, are as follows: 1. An apparent increase of the elastic limit in tension and a decrease of the elastic limit in compression, provided the external load is tensile. The reverse is true when the load is compressive. 2. An elastic after-effeet in which time and temperature are important factors. 3. A state of imperfect elasticity in which Hooke's straight line becomes slightly curved, giving rise to an hysteresis loop. 4. In addition to the apparent increase in the elastic limit, such properties as the hardness, ultimate strength, and resistance to fatigue failure are increased, provided the overstraining has not been carried far enough to make the metal brittle. 5. Correspondingly the ultimate elongation, reduction in area, magnetic quality, ratio of endurance limit (fatigue breaking stress) to elastic limit, and resistance to season cracking (in certain copper alloys) are decreased. The question naturally arises: how do these changes in the properties of a metal resulting from overstrain influence our method of design? The fact that most of the desirable qualities are increased makes overstraining a favorable process, from an engineering standpoint; but on the other hand, the loss of such qualities as perfect elasticity and complete

Jan 1, 1924

By Dan G. Cojocariu, E. Ene-Danalache, I. Huber-Panu

A general model which represents not only batch but also continuous flotation in multi-cell machines is presented. This model considers both the size distribution and the distribution of flotabilities in a size class for valuable mineral particles in the pulp. The general expression is shown to reduce to several previously reported models. In addition, a number of new models are found to arise for different specific assumptions concerning the flotability distribution and/or the size distribution of the particles undergoing flotation. Several of these new models are tested experimentally using laboratory-scale batch and pilot-scale continuous data. Model parameters are estimated from this data and a comparison of calculated recoveries and those experimentally determined are presented. Finally, the influence of the feed rate, aeration rate and valuable mineral content of the feed on the recovery is examined.

Jan 1, 1976

NEW MEMBERS The following list comprises the names of those persons who became members during the period Feb. 10, 1919, to Mar. 10, 1919. ALLEN, ROLLAND CRATEN State Geol., Appraiser of Mines, Lansing, Mich. ALTMAYER, MAURICE ERNEST, Ingenieur des Arts et Manufactures, 145 Rue de la Pompe, Paris, France. AUSTIN, CHARLES L., Assayer, Highland Boy Mine, Utah Cons. Min. Co., Bingham Canyon, Utah. BARTLETT, ARTHUR J., Chief Engr., Louisville Coal & Coke Co. Goodwill, W. Va. BOIES, ORLOW W., Research Chem., Roessler & Hasslacher Chemical Co., 1632 Tenth St., Niagara Falls, N. Y. BRAGG, G. A., Mgr., Experimental Copper Leaching Plant, Mellon Inst. of Industrial Research, Thompson, Nev. BRUSCANTINI, GIOVANNI, Min. Engr., Gen'l Mgr., Sindicato Minero de Cuba, Box 370, Santiago, Cuba. COLONY, R. J Instructor in Geol., Columbia University, New York, N. Y. DAVENPORT, FRANK B., Cons. Engr., 806 Coal Exchange Bldg., WiIkes-Barre, Pa. EATON, S. FORD 120 E. 85th St., New York, N. Y. EBY, J. H., Min. Engr Box 433, Spokane, Wash. ENGELHARDT, EDWARD A., Mgr., Surinaamsche Bauxite Mij, Paramaribo, Dutch Guiana, S. A.

Jan 4, 1919

By R. Michael Craig

Mr. Juvkam-Wold's article is a timely and much needed presentation of the method of depressurization to reduce ground- water inflow into mine shafts. The article is very informative and discusses the effects of depressurization upon shaft inflows adequately. However, the article omits a discussion of another important benefit of depressurization: the reduction of potential for artesian burst or, as it is also called, floor heave. Confined aquifer systems (artesian aquifers) can contain water under several hundred pounds per square inch (psi) of pressure. For example, water levels at elevations of 455 m (1500 ft) or more above the top of the Westwater Canyon member of

Jan 1, 1984

By Aureal T. Cross

THIS paper is a review of the published literature on research in coal geology, principally exclusive of resource studies, which appeared or became available during 1950 and the latter part of 1949. This report is not to be construed as being complete. The papers referred to in the bibliography are those among many more, which were read either in full or in abstract. Undoubtedly other papers were published which either escaped the author's notice or were not available to him. Those which were seen in abstract only (about one fourth of those listed) were not available in time for the inclusion of more than a notice. An outline of all papers listed in the bibliography has been arranged by subjects and reasonable subdivisions with some papers cited under more than one subject. Most papers are indexed according to the principal subject of discussion or research only as to an unusual or noteworthy section of the entire report. There will likely be some disagreement as to the quality or merit of some of the papers selected and the specialist may be supercritical of the outline or organization of papers in his field. It may be that attention has occasionally been drawn to papers reporting old information or conclusions of questionable value. Conferences and Meetings One of the best indications of the growing interest in coal geology problems in the United States is the increasing number of times this field has been the focus of attention at conferences and meetings. Notable among these are the joint meeting of the Society of Economic Geologists and the Geological Society of America at El Paso, November 1949, at which the principal thesis was concerned with low rank carbonaceous fuel deposits, especially of western United States. Among the papers given which are already available were those presented by Barghoorn,'" Parry? Roe? and Parks."' At the annual meeting of the Botanical Society of America in New York, December 1949, a joint meeting of the Paleobotanical and Microbiological Sections was held for which a symposium on Microbiology in Relation to the Geologic Accumulation of Organic Complexes was organized. Publication of the six papers presented by Ralph G. H. Siu, Elso S. Barghoorn, Irving Breger, Claude E. ZoBell, James M. Schopf, and A. C. Thayson is anticipated. At the regular meetings of the Paleobotanical Section at the same time, several other papers of interest reported on coal ball studies, partial coalification of petrified wood, and floras. In Chicago, April 1950, a symposium on Applied Paleobotany was held by the Society of Economic Paleontologists and Mineralogists in conjunction with the American Association of Petroleum Geologists. The five papers presented at this meeting dealt with the use of Paleozoic plant microfossils for stratigraphic work, J. M. Schopf, Devonian-Missis-sippian fossils of the black shales, Aureal T. Cross, Mesozoic plants of stratigraphic value, Th. Just, plant microfossils of the Tertiary, L. R. Wilson, and studies of the Brandon lignite, Elso S. Barghoorn. Early publication of these in the Journal of Paleontology is expected. The Nova Scotia Research Foundation and the Nova Scotia Dept. of Mines sponsored an excellent 3-day conference in June 1950, which dealt with several aspects of coal geology. Papers on coal classification, P. A. Hacquenbard, structure and sedimentation problems in Nova Scotia, T. B. Haites, new techniques of thermal analysis, W. L. White-head, geochemical investigations of Nova Scotia coals, Irving Breger, the role of fossil plant spores in coal correlation and the stratigraphy of the coal-bearing strata of the Appalachian Region, Aureal T. Cross, were given. Some discussions of these papers by those in attendance were recorded, and the entire proceedings is being prepared for publication. In September 1950, an unusual 3-day field conference was held by the Ohio and West Virginia Geological Surveys under the sponsorship of the Coal Geology Committee. This study of the stratigraphy, sedimentation, and nomenclature of the Upper Pennsylvanian and Permian coal-bearing strata of southeastern Ohio, southwestern Pennsylvania, and northern West Virginia was augmented by two discussions on associated rocks (clays and shales) and stratigraphic nomenclature at Wheeling and Morgantown, West Va. An extensive guidebook was prepared, and transcriptions of the Morgantown meeting were made. As a follow-up of the September field conference, a round-table discussion was held on this general topic at a special open meeting of the Coal Research Committee in conjunction with the November meeting of the Geological Society in Washington. Short prepared statements to invite discussion were given on each of several topics by L. M. Cline, Carl 0.

Jan 1, 1953

By Aureal T. Cross

THIS paper is a review of the published literature on research in coal geology, principally exclusive of resource studies, which appeared or became available during 1950 and the latter part of 1949. This report is not to be construed as being complete. The papers referred to in the bibliography are those among many more, which were read either in full or in abstract. Undoubtedly other papers were published which either escaped the author's notice or were not available to him. Those which were seen in abstract only (about one fourth of those listed) were not available in time for the inclusion of more than a notice. An outline of all papers listed in the bibliography has been arranged by subjects and reasonable subdivisions with some papers cited under more than one subject. Most papers are indexed according to the principal subject of discussion or research only as to an unusual or noteworthy section of the entire report. There will likely be some disagreement as to the quality or merit of some of the papers selected and the specialist may be supercritical of the outline or organization of papers in his field. It may be that attention has occasionally been drawn to papers reporting old information or conclusions of questionable value. Conferences and Meetings One of the best indications of the growing interest in coal geology problems in the United States is the increasing number of times this field has been the focus of attention at conferences and meetings. Notable among these are the joint meeting of the Society of Economic Geologists and the Geological Society of America at El Paso, November 1949, at which the principal thesis was concerned with low rank carbonaceous fuel deposits, especially of western United States. Among the papers given which are already available were those presented by Barghoorn,'" Parry? Roe? and Parks."' At the annual meeting of the Botanical Society of America in New York, December 1949, a joint meeting of the Paleobotanical and Microbiological Sections was held for which a symposium on Microbiology in Relation to the Geologic Accumulation of Organic Complexes was organized. Publication of the six papers presented by Ralph G. H. Siu, Elso S. Barghoorn, Irving Breger, Claude E. ZoBell, James M. Schopf, and A. C. Thayson is anticipated. At the regular meetings of the Paleobotanical Section at the same time, several other papers of interest reported on coal ball studies, partial coalification of petrified wood, and floras. In Chicago, April 1950, a symposium on Applied Paleobotany was held by the Society of Economic Paleontologists and Mineralogists in conjunction with the American Association of Petroleum Geologists. The five papers presented at this meeting dealt with the use of Paleozoic plant microfossils for stratigraphic work, J. M. Schopf, Devonian-Missis-sippian fossils of the black shales, Aureal T. Cross, Mesozoic plants of stratigraphic value, Th. Just, plant microfossils of the Tertiary, L. R. Wilson, and studies of the Brandon lignite, Elso S. Barghoorn. Early publication of these in the Journal of Paleontology is expected. The Nova Scotia Research Foundation and the Nova Scotia Dept. of Mines sponsored an excellent 3-day conference in June 1950, which dealt with several aspects of coal geology. Papers on coal classification, P. A. Hacquenbard, structure and sedimentation problems in Nova Scotia, T. B. Haites, new techniques of thermal analysis, W. L. White-head, geochemical investigations of Nova Scotia coals, Irving Breger, the role of fossil plant spores in coal correlation and the stratigraphy of the coal-bearing strata of the Appalachian Region, Aureal T. Cross, were given. Some discussions of these papers by those in attendance were recorded, and the entire proceedings is being prepared for publication. In September 1950, an unusual 3-day field conference was held by the Ohio and West Virginia Geological Surveys under the sponsorship of the Coal Geology Committee. This study of the stratigraphy, sedimentation, and nomenclature of the Upper Pennsylvanian and Permian coal-bearing strata of southeastern Ohio, southwestern Pennsylvania, and northern West Virginia was augmented by two discussions on associated rocks (clays and shales) and stratigraphic nomenclature at Wheeling and Morgantown, West Va. An extensive guidebook was prepared, and transcriptions of the Morgantown meeting were made. As a follow-up of the September field conference, a round-table discussion was held on this general topic at a special open meeting of the Coal Research Committee in conjunction with the November meeting of the Geological Society in Washington. Short prepared statements to invite discussion were given on each of several topics by L. M. Cline, Carl 0.

Jan 1, 1953

By John Wulff, J. H. Hollomon

Service failures in brass condenser tubes are often due to corrosion. One of the commonest types of corrosion reveals a surface structure of redeposited copper.' The study of the effect of alloy addition agents in preventing this kind of corrosion has received impetus from the extensive publication of Bengough and May.2 The mechanism of such inhibition gauged from immersion corrosion,2 cell corrosion,3 and electrolytic potential4 measurements is controversial. This controversy may be attributed in part to a lack of definite knowledge5 of the actual nature of the initial films formed in corrosion experiments. In our own corrosion work on copper and 70-30 brass this lack became apparent and necessitated an examination of surface films by X-ray and electron diffraction methods. The present paper is but an introduction to the subject of inhibition and reports the structure of films formed in active corrodents. Experimental Procedure The arsenical coppers and brasses used in this investigation were made by one of the writers* in the plant of the Revere Copper and Brass Co. at Rome, N. Y. Standard commercial melting practice was followed. O.F.H.C. copper and electrolytic zinc were used and all arsenic additions were made by additions of a master copper alloy. The final analyses are given in Table I. Likewise, the extrusion, cold-rolling, and intermediate anneals employed followed standard usage. Final heat-treatments were given to all materials to produce a similar grain size (0.035 to 0.045 mm. for brass and 0.015 to 0.025 for copper) for the alloys containing various percentages of arsenic. Samples 1/2 by M by 1/4 in. were cut from sheet material resurfaced and finished with 0000 metal-lographic papers. The surfaces were all degreased in alcohol and benzine before immersion. After immersion in the corrodent, they were washed gently in tap water, dipped first in alcohol and then in pure benzine and allowed to dry in the diffraction apparatus. The reflection electron diffraction apparatus used has been described by Burwell and Wu1ff.6 Fig. I is typical of the photo-grams obtained. The X-ray apparatus was

Jan 1, 1941

By E. Lancaster-Jones

THE gravity magnitudes obtained by means of observations with the Eötvös balance in the field are necessarily resultant or total effects due to all abnormalities of mass distribution, including even the effects due to the ellipticity and rotational motion of the whole earth. Since the object of the survey is to isolate the effects which arise solely from some particular subterranean feature, and to deduce therefrom the configuration and extent of this feature, the first step is to eliminate from the observed effects all those due to "disturbing" (i. e., unwanted) features, whether above or below the surface of the ground. The disturbing features have different characteristics, according to their situation relative to the center of the balance and to the horizontal plane through the foot of the balance, or station point; this diversity was recognized by Eötvös, who divided the total effects into so-called Normal, Terrain, Topographical, Cartographical and Subterranean effects. This classification has been adhered to by most subsequent investigators, but the writer prefers to employ the term "three-dimensional," which really indicates the essential character of the class of effect known as "Subterranean," at any rate from the standpoint of the computer of effects. Before disturbing effects can be eliminated, the features must be measured up or surveyed, whether by topographical, mining, or boring methods, and then the effects of each feature calculated and subtracted from-the total observed effects. After this the problem of interpreting the residual effects will itself necessitate the computation of the assumed feature, or even a series of trial features.

Jan 1, 1928