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By E. L. Tucker

PREVIOUS investigations of E. L. Tucker and R. E. Head' related in particular to the effect of cyanogen compounds on galena, sphalerite, and pyrite, and their behavior in the presence of such com- pounds. The present contribution deals with the float- ability of the copper minerals and of pyrite. All experiments were performed on minus 200-mesh material, the method of preparation being the same as that described in the previous article. Flotation tests were made in a small mechanically agitated machine of 50-g. capacity designed in this laboratory by Gates and Jacobsen." General Naval Stores pine oil No. 5 and potassium xanthate were used in constant amount in all of the experiments; these agents were selected because of their present wide use in the flotation of copper minerals. Lime additions were varied to secure four 'final hydrogen ion concentrations, namely, neutral, 0.0005 per cent CaO, 0.003 per cent CaO, and 0.02 per cent CaO. The variation in lime addition was introduced to include the range of alkalinities employed in actual flotation practice.

Jan 1, 1926

By W. A. Thomas

STEAM is, and doubtless always will be, the basic power in the anthracite industry, either directly applied through engines and pumps or electrically. The rapidity with which electric power is being applied to the mining and preparation of anthracite leaves little doubt as to its utility and economy. There is practically no operation, except possibly the drilling of hard rock, that has not been successfully electrified and the matter of drilling is handled economically with electrically driven compressors and the standard compressed-air drills. Conservation and the seemingly ever-increasing cost of production, justify careful consideration of the possible results of the more extensive use of electric power in the industry. It is not planned to discuss, herein, the relative economies of individual applications but to consider the relative economy and flexibility of steam and electric power. The reports available for the year 1920 indicate a production of slightly over 80,000,000 tons of anthracite, of which 8,843,500 tons were used for power and heating purposes; in other words, over 11 per cent. of the production was used at the mines. Some of this was used to generate electric power at the mines, about 160,000,000 kw-hr., while 150,000,000 kw.-hr. was purchased from the public utility companies. One large producer, who is buying some electric power and generating some, used over 13 per cent. of the production for power and heating at the mines. Another producer, where considerable electric power is generated on the properties, is using less than 9 per cent. of the output for power and heating. One of the largest producers has a fuel consumption of over 15 per cent. of the output, besides which considerable power is purchased. A careful study of the field indicates that steam-operated plants use upwards of 13 per cent. of the production for power and heating, while electrically operated plants use about 1 per cent. for heating; so that, for steam-power purposes at least 12 per cent., or 268.8 lb., are used for power out of each ton produced.

Jan 9, 1921

By Mark T. Atwood, Franklin B. Carlson, Louis H. Yardumian

The Oil Shale Corp. (TOSCO) is investigating the application of its oil shale retorting technology to coal processing in its 25-tpd retorting pilot plant. Low temperature char, with a high heating value, plus tar and gas have been produced from high moisture content, low heating value, subbituminous coal. The process, which has been named the TOSCOAL process, uses heated ceramic balls to provide the heat for retorting the coal. One ton of as-mined, subbituminous coal produces approximately 1/2 ton of char, 1/2 barrel of tar, and 1600 standard cubic feet (scf) of gas when the retorting is conducted at 970°F. Properties and yields of the products are presented and compared with Fischer assay yields.

Jan 1, 1975

By J. L. W. Birkinbine

INTRODUCTION. This paper is a discussion of a part of the mineral wealth of the States of Oaxaca and Puebla, Mexico. It does not refer to the precious metals, some miles of which, in these States, are said to have been worked before the advent of the Spanish conquistadores in the sixteenth century, as my purpose is to invite attention to the exploration of deposits of coal and iron-ores in the Mixteca region. The prominence given to coal is warranted by the great effect of the scarcity of fuel upon the industrial development of Mexico. Under the progressive administration of President Porfirio Diaz, the Republic has made wonderful advances in the past three decades; and this progress would have been greater but for the limitations imposed by expensive fuel. In the spring of 1906 I was detailed by the Birkinbine Engineering Offices, of Philadelphia, to accompany A. B. Adams, of New York, in a reconnoissance of reported deposits of iron-ores in the State of Oaxaca. The result of this expedition was the formation, in 1907, of the Oaxaca Iron & Coal Co., of which Mr. Adams became, and has remained, President and General Manager, and I have spent the past three years as Chief Engineer of this company in Mexico, principally in western Oaxaca, where field-headquarters were established. GEOGRAPHY AND POPULATION. Although the geographical anti topographical, features of the Republic of Mexico are well known, few realize that the majority. of its population is domiciled in the States which immediately surround the capital city of Mexico, including the Federal District, Mexico, Tlaxcala, Morelos, Puebla,

Sep 1, 1910

By V. Niemitz

Approximately 30 miles east of Chicago on the southern shores of Lake Michigan stands Bethlehem Steels newest fully integrated steelmaking facility-the billion dollar Burns Harbor plant. The first phase of what will ultimately be the most completely integrated and flexible materials handling system for a steel mill in the western hemisphere is now complete.

Jan 1, 1970

By Hans S. Carlsson

Like most industrial processes, nuclear power production creates wastes, which have to be handled and ultimately disposed of in a safe manner. Some of the wastes contain very long-lived radioactive substances and have to be isolated for very long periods of time before they have decayed to harmless levels. Sweden, like many other countries with similar geology, intends to use crystalline rock for isolating the high-level nuclear waste from the biosphere. The suitability of a rock mass for a repository needs to be investigated extensively. Apart from the political and practical considerations for a site selection, a detailed study has to be performed in terms of geology, hydrogeology, geophysics, geochemistry and rock mechanics. The responsibility of the site selection studies in Sweden is entrusted to the Swedish Nuclear Fuel Supply Company, Division KBS (SKBF/KBS) . The paper gives a brief presentation of the "Standard Program" for the studies that will be carried out during 1980-1990. Modifications of the program are justified on the basis of gained experience or specific circumstances for each site. The program is compiled by the Geological Survey of Sweden (SGU) in cooperation with KBS.

Jan 1, 1982

E. D. Peters, Jr., Dorchester, Mass.: This paper of Mr. Keller's seems to me a step in a direction that has been very little exploited, and iff likely to lead to valuable practical re-

Jan 1, 1899

By Hermann Bach, Walther Hänig, Willi Gehrhardt, Ernst Theurich, Walter Langner

With the construction of the Magdeburg zinc works, the Georg von Giesche's Erben Mining Co. of Breslau has to a certain extent completed the program of reconstruction which it set as its goal after the boundaries of Upper Silesia were drawn by the Treaty of Versailles. During its history, covering.more than two centuries, zinc and lead mining has been its chief activity. Through the new boundaries established, it lost to Poland all its mines and smelters, including five distillation smelters. Of its extensive properties, there remained only an apparently unimportant and unexplored portion of the old Bleischarley ore field which, however, happily made possible the resumption of its old business. In 1925 the Deutsch-Bleischarley shaft-only a few kilometers from the old Bleischarley shaft—was sunk and developed, and in May 1926 production of lead and zinc ore was resumed. As facilities for smelting were lacking, the ore was at first delivered to the neighboring smelters, which had now become Polish. Realization of the plan to build its own zinc works had to be postponed at first for lack of capital. In the meantime, however, plans for the new works were worked out in all details. After extensive experimentation in a semicommercial pilot plant it was decided, at the end of 1928 and the beginning of 1929, to use the electrolytic process and, for economic reasons, to place the works at Magdeburg. With zinc at the approximate price level that had ruled since the Deutsch-Bleischarley mine had begun working, it was hoped that the plan could be completed in 1930 with the company's own resources. However, falling metal prices, already noticeable in 1929, made this impossible, and further postponement for a time became necessary. Finally, at the end of July 1933, the funds for building the works became available, in the form of a loan granted under the first employment

Jan 1, 1937

Jan 1, 1908

By R. W. Bond

The gas-lift is a comparatively recent development in the Oklahoma and Kansas fields. It was used to some extent in the old Dilworth field several years ago, but the first extensive installations were made in the Tonkawa and Garber fields in Oklahoma early in the year 1926. Compressor Equipment During the early development of the system, the equipment used generally consisted of small tandem compressors of about 250 cu. ft. per min. displacement, driven by automotive-type gas engines, using a short belt drive. These compressors were first installed at the individual wells largely as an experiment. After the experimental installations had proved the method a success, it was considered economically advisable to centralize the compressor equipment in strategically located stations. However, as the information in regard to "gas-lift flowing life" was anything but definite, and the most optimistic estimates in regard to it did not exceed six months, portability of equipment was still the first consideration in the minds of many operators, who continued to install srnall semi-portable com-pressors in their centralized stations. As electric power became available in the fields, the electric motor came rapidly into use as the prime mover for the small compressors. The operating cost of this motor is greater than that of the automotive-type gas engine for the same power output, but the greater continuity of service tends to balance the extra cost. Aside from the semi-portable units, a number of strictly portable compressors were used. These consisted of automotive-type gas engines direct connected to vertical compressors. The unit was assembled on one base and could be mounted on wheels or skids as desired. The chief objection to these, in the writer's opinion, was their small capacity— approximately 150 cu, ft. per min.—which made it necessary to use two, three, and sometimes more units per well, thus making the installation rather costly. However, they have been found valuable for test purposes and emergencies, where installation time is an important factor.

Jan 1, 1928

By L. D. Jaffe

IT is now well established that quenched and tempered titanium alloys have much better ductility when the quenching is from a two phase a-B structure, rather than from an all B structure. The corresponding microstructural differences, however, have not been shown in previous publications. Accordingly, specimens were cut from a % in. rod of commercial RC-130A, containing 7.9 pct Mn and 0.12 pct C, which had been previously hot rolled, heated 1 hr at 1100°F, and air cooled. (The same heat has been studied by others." 7 Samples about 1/4 in. cube were heated in helium 1/2 hr at 1450' or 1700°F, quenched in brine, tempered in helium 1 hr at various temperatures up to 1250°F, and quenched in brine. They were then sectioned and metallo-graphically examined, using an etchant of HF-HNO, in glycerine. As quenched from 1700°F, the microstructure observed was clear /3. (Probably also present was U, as the hardness was 400 Vhn, but w is not yet reliably revealed by any metallographic technique.) When the /3 quenched alloy was tempered at a high temperature, a precipitated as a grain boundary film

Jan 1, 1957

By Harvey N. Davis

MUCH has been written and said during the last twenty years about the place of the engineer in modern life, about the fundamental role that he plays both in developing and in maintaining the material foundations of modern civilization, about the advantages, and also the dangers, of the machine age that he has inaugurated, about the Frankenstein problems that he has unconcernedly foisted upon a generation utterly unable to cope with them, and about the obligation that rests upon him to stop inventing machines and turn his almost legendary energy and skill to inventing institutions that will constitute a solution of the problems he has raised, and contrariwise about his utter inability to offer wise or useful counsel in fields outside the narrow boundaries of his technical training.

Jan 1, 1938

By E. W. Engelmann

RAPID progress has been made during the past year in the copper mills throughout the country. Particular efforts have been made to increase the fine-grinding efficiency by the installation of larger classifying units operating in closed circuit with ball mills, such as the 78-in. high-weir Akins installation at the Phelps Dodge plant at Ajo, Ariz.; also the Type "FX" Dorr classifiers of Nevada Consolidated at McGill. Nev. and the "FX" Dorr bowl classifier of the Braden Copper Co. in Chile. Some of the copper milling plants in the Southwest, such as Chino in New Mexico and Ray Con. in Arizona, have replaced rolls operating wet in their fine-grinding circuit by rod mills. At Hollinger primary rod mills were formerly used in open circuit followed by pebble mills in closed circuit with classifiers. They now have primary ball mills in closed circuit with large extra heavy classifiers and no secondary mills. This new installation is producing the same grinding on 5000 tons per day with a reduction in cost of nearly 4c. per ton. At the Braden plant, in Chile, short-head Symons crushers have replaced 54-in. rolls, thereby in- creasing crushing capacity with some saving in maintenance cost.

Jan 1, 1939

By R. W. Waterfill

MANY existing ore deposits of valuable metals have been worked out in their upper surface levels and the continued productivity of these mines is dependent on their extension to greater depths in the earth. The maximum depths at present reached are about 6000 to 8000 ft. below the surface, with no evidence of an impoverished ore vein. These mines are widely distributed; some of the best known are in South Africa, Brazil, India and in the western sections of the United States. Among the factors which increase the difficulty of working these mines at increasing depths are hoisting, rock pressure and temperature. The manner and effectiveness with which these problems are met will, no doubt, determine in a large measure the ultimate depths to which any mine can be profitably worked. The most critical of these three factors at present is the increase in temperature with depth. The high temperature and humidity in many of these mines at present is severely detrimental to the health of the workers and greatly hampers their efficiency. Some have almost reached a condition in which the human system cannot survive. The problems involved in the cooling and ventilation of mines have all been ably analyzed and presented in previous articles. For this reason, only a resume of conditions affecting the cooling and conditioning of deep and hot mines will be given in this paper before attention is directed to possible methods of improving atmospheric conditions in the working levels.

Jan 1, 1929

By R. W. Waterfill

MANY existing ore deposits of valuable metals have been worked out in their upper surface levels and the continued productivity of these mines is dependent on their extension to greater depths in the earth. The maximum depths at present reached are about 6000 to 8000 ft. below the surface, with no evidence of an impoverished ore vein. These mines are widely distributed; some of the best known are in South Africa, Brazil, India and in the western sections of the United States. Among the factors which increase the difficulty of working these mines at increasing depths are hoisting, rock pressure and temperature. The manner and effectiveness with which these problems are met will, no doubt, determine in a large measure the ultimate depths to which any mine can be profitably worked. The most critical of these three factors at present is the increase in temperature with depth. The high temperature and humidity in many of these mines at present is severely detrimental to the health of the workers and greatly hampers their efficiency. Some have almost reached a condition in which the human system cannot survive. The problems involved in the cooling and ventilation of mines have all been ably analyzed and presented in previous articles. For this reason, only a resume of conditions affecting the cooling and conditioning of deep and hot mines will be given in this paper before attention is directed to possible methods of improving atmospheric conditions in the working levels.

Jan 1, 1929

By Robert Bakish, William D. Robertson

AFTER more than fifty years of investigation and continuing failure in service, a satisfactory mechanism to explain stress corrosion cracking in homogeneous alloys is still lacking. The relative chemical activity of grain boundaries and adjacent grains, inferred from the boundary structure, has been used to explain intergranular cracking in a brass.' This concept is probably correct as a general hypothesis, but it requires much more extensive development in order to explain satisfactorily the observed phenomena. For example, the specific function of the solute in an alloy must be considered, because intergranular failure does not occur in pure metals,' which are structurally similar to homogeneous alloys. Also, in this connection, an inter crystalline fracture path in binary copper alloys can be changed to a transcrystalline path by relatively small ternary additions.' The fracture path in ß brass is predominantly transcrystalline,' in contrast with an inter crystalline path in a brass. Whether the two different fracture paths are the result of a difference in composition, crystal structure, or the state of long range order is unknown and cannot be determined with ß brass, because only the ordered state can be obtained at room temperature. The study of chemical activity at structural sites in the Cu-Zn system is restricted by the formation of opaque films in an ammonia environment in which stress corrosion cracking is generally observed. Furthermore, both components of the alloy are chemically active and the interpretation of observations is therefore relatively complicated. The Cu-Au system is a better choice for the purpose of studying structural factors. In particular, CuAu is very susceptible to cracking in ferric chloride and opaque films are not formed in this solution; it may be obtained in different states of long and short range order; and, finally, only copper is oxidized in dilute ferric chloride, which considerably simplifies the chemical problem. To provide information necessary for a more general explanation of stress corrosion cracking in homogeneous solid solutions, the following structural factors have been investigated in a Cu-Au alloy having a composition corresponding to Cu,Au: 1) the effect of long and short range order; 2) the structural sites from which copper is removed from the annealed and cold worked polycrystalline alloy; and 3) the effect of annealing time and temperature on structural reactions in the cold worked alloy. Experimental Procedure A Cu-Au alloy of nominal Cu3Au composition was cast from cathode copper and high purity gold and fabricated into sheet and wire. Chemical analysis for copper and gold indicated 48.92 wt pct Cu and 51.01 pct Au. Quantitative spectrographic analysis indicated 0.01 pct Ag, 0.002 pct Pd, 0.001 pct Pb, and 0.002 pct Fe, with traces of magnesium, silicon, and zinc. Presumably most of the remaining 0.055 pct corresponds to the limits of analytical precision. Heat treatments of wire and sheet were conducted in argon or vacuum. Wire specimens, 0.064 in. diam, were heated for 1 hr at 850 °C to establish a definite

Jan 1, 1957

By THOMAS G. FEAR

THE COAL DIVISION started its share of the annual meeting Monday morning with a study of coal classi fication. A. C. Fieldner was in the chair. The report of the tellers of the ballot for division chairman, stating that Thomas G. Fear had been elected to that office, was read by M. D. Cooper. Mr. Fear acknowledged the honor in a few words. In reviewing the history of the Coal Classification Committee the chairman pointed out that this was its third symposium, the last previous one having been held at the 1930 Annual Meeting. Throughout its work the com¬mittee has had the active cooperation of the Canadian workers who are interested in the subject which should result in a uniform scheme of classification in Canada and the United States. F. E. Lathe, of the National Research Council, Ottawa, abstracted the first two papers of the session entitled "Determination of the Alkali-Soluble Ulmins in Coal," by Edgar Stansfield and K. C. Gilbart, and "Moisture Determination for Coal Classification," by the same authors. The third paper "Condition of Water in Coals of Various Ranks"' was presented by its author, A. W. Gauger. Written discussions of these papers were presented by H. C. Porter and Gilbert H. Cady. In the oral discussion which followed, W. T. Thom, Jr., brought out the advisability of considering age as a factor in classification. Mr. Fieldner favored retaining bed moisture as a partial classification basis, stating that a review of many coal analyses revealed a remarkable consistency in this item in samples from a given mine particularly where the moisture content was not high. Mr. Porter pointed out that the structure and porosity of coal often have much to do with its moisture content and that these vary in different parts of a seam, particularly in anthracite. Mr. Gauger expressed doubt as to whether the Stansfield method gives the true moisture content of coal, which is needed for classification purposes.

Jan 1, 1932

By E. Teghtsoonian, K. G. Davis

THE preparation of cobalt crystals offers problems: on cooling through 400°C a phase transformation takes place whereby the structure changes from face-centered cubic to the low temperature close-packed hexagonal form. There are a few references in the literature which describe the preparation of cobalt crystals for magnetic work1,&apos; where melt-solidification methods were used. Reasons will be given why such methods were found unsuitable for our purposes. The following techniques were tried: 1) Solid state methods. Any mechanical shaping of tensile specimens would lead to uncertainty with regard to residual strains. With this in mind, following Kaa, strain-anneal and grain growth techniques were extensively investigated. In no Case were useful single crystals obtained. The transformation boundaries, which are crystallographically similar to twin boundaries, are probably extremely stable and inhibit the grain growth. 2) Growth from the melt. Normal melt-solidification methods were tried, using recrystallised alumina crucibles, and also a osoft moldo technique in which cobalt rod was packed in alumina powder. Trouble was encountered with gas evolution on solidification of the melt, giving porosity. Some adhesion of cobalt to the alumina also took place. Only a small proportion of the runs gave single crystals. 3) Zone-refining. Much the best results have been obtained using an electron-beam floating zone refiner. The refiner, based on a design by Calverly et Al .5 had a single-turn tungsten filament. It was operated at 600 v with an emission current around 45 ma. Commercial cobalt rod 1/8 in. in diam was given one pass at a rate of zone travel normally 25 cm per hr, under a vacuum approximately 10-5mm of Hg. Over 50 pct of the runs gave long sections of single crystal. Crystals up to 2o Cm long with good uniformity of cross section and straightness have been grown in this way. Increase in the length of the molten zone resulted in higher single-crystal yields, but control of zone stability was reduced. Sub-boundaries in the zoned crystals were few, and Laue X-ray spots were sharp. The success of the method is believed to lie in two factors, namely i) the absence of crucible restraints during the transformation, and ii) extreme axiality of heat flow during cooling. The axes of the zoned crystals were clustered around the [ 1010] pole, the pole of the basal plane being at least 60 deg from the specimen axis. Crystals grown at lower rates of zone travel showed the same orientation range, Fig. 1. This orientation is similar to that for other hexagonal metals grown from the melt, which is a little surprising when the mode of formation of the hexagonal phase is considered. The preferred orientation is probably caused by anisotropy of heat conduction, i.e., that crystal which can most effectively conduct heat away from the transformation interface will be favored. Fig. 2 shows the area on a standard cubic stereo-gram in which there are no poles more than 60 deg from one of the four < 111> directions. This area

Jan 1, 1962

Jan 1, 1920

By R. W. Guard

ALTHOUGH etching techniques have been developed for revealing dislocation sites in several metals and ionic crystals,h t is valuable to extend the technique to new metals. An etch pit method for nickel has been developed on the basis some suggestions of Dr. John R. Cuthill of the National Bureau of Standards who had observed etch pits in creep specimens of nickel. The etchant used was proposed first by wensch2 for revealing grain size in nickel. The present paper describes the evidence that the technique can be used to reveal dislocations and gives the conditions under which etching can be carried out. The specimens examined were vacuum melted high-purity Ni (99.985 pct Ni) and commercial "A" nickel (99.8 pct Ni). Both materials contained greater than 0.008 pet C and had been annealed in nitrogen or dry hydrogen at 1100o to 1200°C. This gave a grain size of 1.5 mm in the high-purity nickel and 0.050 mm in "A" nickel. Tensile specimens (0.254 in. diam) were deformed from 0.25 to 10 pct at room temperature and then heated for 1/2 hr at different temperatures from 400" to 900°C. The specimens were sectioned longitudinally then polished electrolytically in 60 pct H2SO4 and etched in 35 pct H3PO4 solution at 0.2 to 0.4 v for 30 sec to 3 min. The best method for setting the proper voltage for etching is to increase the voltage until gas bubbles are evolved vigorously from the specimen and then cut it back by 10 pct. It is necessary to heat the specimen above 500°C after deformation in order that etch pits will be formed. This "decoration" treatment permits carbon to segregate to the dislocation rendering them sensitive to etching. It was demonstrated that carbon was the decorating impurity by decarburizing some specimens in wet H2 at 1200°C. The susceptibility to etch pitting was lost following this treatment but could be restored by carburizing in contact with graphite. Some rearrangement of the dislocations in the as-deformed structure occurs on heating at 500oC and above so that the technique can not be used to study the nature of dislocation patterns in deformed specimens. Extended etching does not change the number of pits although the background becomes rough and the pits quite large. The polycrystalline specimens with various strains were examined after annealing at different temperatures. Typical patterns are shown in Figs. 1 and 2. In the unstrained specimen, Fig. 1, the density of pits is 2.5 X 10&apos; per sq cm. All grains show pits regardless of their orientation although there is a

Jan 1, 1961