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By Paul F. Kerr

QUARTZ of a certain kind, is one of our strategic minerals, and Brazil is probably the one important available source. Crystals of quartz of suitable size and perfection for piezoelectrical application are rare; their most outstanding use is in radio work. Clear quartz, or "crystal," free from twinning, cracks, foreign particles of other disturbing lines of growth, and gaseous or liquid inclusions, is cut into plates which provide excellent control of frequency in broadcasting. The squares or rectangles are less than a millimeter in thickness and ordinarily on the order of 1 in. along each side. They are cut at definite angles with respect to the axes of the crystal, and ground with opposite surfaces parallel. Each small slab must be a section of one crystal, uniform throughout in atomic alignment. The thickness of the chip controls the frequency of a broadcast and it is most important to have the plates oriented and ground with utmost precision. Opposite surfaces are parallel to within 0.001 mm. and expansion or contraction due to the temperature is limited to one part in a million.

Jan 1, 1942

By D. I. Bardos, Paul A. Beck

A MARK, Boren, and westgrenl in their X-ray diffraction study of manganese alloys with 10 to 25 at. pct Si reported the occurrence of a phase with complex crystal structure in a Mn + 14.5 at. pct Si alloy after annealing at 800° or at 600°C. Recently Kuzma and Gladyshevskii2 identified Mn6Si as an R phase,3,4 the second binary R phase known. (A binary R phase was previously found in the Mn-Ti system by Waterstrat.5) A ternary R phase was reported earlier0 near the Mn-Si binary border of the Ti-Mn-Si system at 1000°C. In the light of the Russian work it now appears that this "ternary" R phase may be in fact an extension of the binary (Mn6Si)R phase. As already found by Amark, Boren, and Westgren, the corresponding binary phase is absent at 1000°C; the effect of titanium is evidently to stabilize it up to higher temperatures. In a recent paper Wieser and Forgeng7 gave the boundaries of this binary phase, which they referred to as 6. In order to re-examine the identity of this phase, an alloy of Mn + 14.5 at. pct Si was prepared by induction melting in helium atmosphere and annealed for 3 days at 800°C. The powder pattern, taken with an asymmetrical focusing camera of large dispersion and shown in Table I, was found to be that of the R phase, in agreement with the results of Kuzma and Gladyshevskii. For comparison, Table I also lists

Jan 1, 1965

By Karl J. Benecke

Though the first patent on a bucket wheel excavator (BWE) was granted in 1881 in the US, this technology was developed in Germany to the high standards of today. However, this development was only possible in parallel with development of shiftable belt conveyors and boom stackers. The combination of these three types of equipment in the open pits of the Federal Republic of Germany has made lignite the cheapest energy source for power generation, despite the low heating value of German lignite on the order of 8500 kJ/kg (3600 Btu/lb) only. Comparing the costs for fuels used in power generating on the basis of their heating value, the relation between lignite, high quality black coal, and imported crude oil is on the order of 1 to 1.5 to 2.5, hence highly in favour of lignite.

Jan 8, 1979

By Edward H. Robie

THE registration badges gave out, there were not enough programs, the Pioneer Hotel's rooms were insufficient, and some hundred applicants for banquet tickets had to be turned down at the Institute's Regional Meeting in Tucson, Nov. 1-5. Minor inconveniences these, however, occasioned by the fact that, optimistic as they are in Arizona, about half again as many partook of the week's activities as were expected. For this, the local program committee can be blamed-both the technical and social features were too attractive in quantity and quality. Seriously speaking, though, the Institute has probably never had a more successful Regional Meeting than this one. It being the first that has been held in Arizona in 22 years, no effort was spared to make it the distinctive gathering that it was.

Jan 1, 1938

All the TECHNICAL PUBLICATIONS and CONTRIBUTIONS published in 1940 are available at Institute headquarters, unless otherwise noted. They are also on file in many public, university and technical libraries and, when so indicated in the list, may be found in the TRANSACTIONS. TECHNICAL PUBLICATIONS in Classes A-Metal Mining, B-Milling and Concen-tration, H-Industrial Minerals, and I-Mining Geology are distributed in MINING TECHNOLOGY, which is issued every other month. Technical Publications in Classes C-Iron and Steel Division, D-Nonferrous Metallurgy and E-Institute of Metals Division are distributed in METALS TECHNOLOGY, which is issued twice quarterly. TECHNICAL PUBLICATIONS in Class G-Petroleum Division are distributed in PETRO-LEUM TECHNOLOGY, which was issued quarterly in 1940 but will be issued every other month in 1941. TECHNICAL PUBLICATIONS in Classes F-Coal Division, J-Mineral Industry Education Division, K-Mining Administration, and L-Geophysical Methods of Exploration are issued as separate pamphlets. An Institute member is entitled to one copy of any TECHNICAL PUBLICATION or CONTRIBUTION. Copies of TECHNICAL PUBLICATIONS listed have been mailed to members of the Institute accord-ing to their registration by classes. CONTRIBUTIONS and other TECHNICAL PUBLICA-TIONS will be sent upon request. A member may purchase an additional copy of a TECHNICAL PUBLICATION or a CONTRIBUTION at one cent a page; minimum charge, 25¢. Nonmembers may purchase any CONTRIBUTION or a TECHNICAL PUBLICATION of the F, J, K, or L classes at the same rate, but the nonmember price per copy for METALS TECHNOLOGY, MINING TECHNOLOGY or PETROLEUM TECHNOLOGY is $1.25 domestic, $1.35 foreign countries. TECHNICAL PUBLICATIONS (separate pamphlet form), $2 per annum domestic, $2.50 foreign. METALS TECHNOLOGY, $7 per annum domestic, $7.80 foreign (Iron and Steel Division and Institute of Metals Division ferrous and nonferrous papers). MINING TECHNOLOGY, $6 per annum domestic, $6.60 foreign (metal mining, milling and concentration, Industrial Minerals Divi-sion, and mining geology papers.) PETROLEUM TECHNOLOGY, $6 per annum domestic, $6.60 foreign. Bound volumes have been mailed to members that have requested them, and MINING and METALLURGY is mailed each month. A member is entitled to one volume a year on his membership and he may purchase for $2.50 one copy of a volume not already received; additional copies of the same volume, $5. Nonmembers may pur-chase the volumes listed, at $5 each, plus 60 cents for Canadian or foreign postage. Extra single copies of MINING AND METALLURGY, 25¢ current issue, back numbers 50¢ each to members; to nonmembers 506 current issue and $1 each, back issues. Subscription price to nonmembers and to members for extra copies, $3 per annum domestic, $4.00 foreign.

Jan 1, 1940

By R. R. Seeber

(Pittsburg Meeting, March, 1910.) IN the copper-mining district of northern Michigan a fair-sized mine usually operates two or more shafts along the strike of the lode, these shafts being usually at least 1,000 ft. apart. The tonnage to be hoisted from each shaft is large-from 13,000 to 25,000 tons per month. The hoisting-engines used are generally steam-driven, non-condensing, duplex engines with Corliss valves, supplied by steam from separate boiler-plants where the distance between shafts is great. In an attempt to centralize power-plants and secure central-station economies, the Winona Copper Co. installed an electric hoist of the Ilgner type, with Ward Leonard control. A brief description of this plant has already been published.1 The only point of variation from the simple Ilgner set lies in the connection of two generators to a single induction-motor by flexible couplings. These generators serve motors which operate hoisting-drums at separate shafts, viz., No. 4 shaft, Winona, and No. 1 shaft, King Philip. , The hoist for No. 4 shaft, is about 1,700 ft. from the power-plant, and in this building the motor-generator set is placed. No. 1 King Philip hoist is 1,500 ft. from the motor-generator set. The equipment of the motor-generator set is as follows: In the middle of the set is a 12-pole, 450-h-p., 600-rev. per min., 2,080-volt, three-phase, 60-cycle, variable-speed induction-motor, connected on each side to a 20-ton fly-wheel which is 10 ft. in diameter, and to a 6-pole, 170-kw, 575-volt, interpole, direct-current generator. On each side of the shaft is placed a separate exciter, which delivers current at 125 volts. The lubrication of the four main bearings that support the fly-wheels * Presented also, by mutual agreement, at the meeting of the American Institute of Electrical Engineers, New York, N. Y., Mar. 11, 1910. Engineering and Mining Journal, vol. lxxxviii., No. 3, p. 110 (July 17, 1909).

Sep 1, 1910

By J. W. Rutter, K. T. Aust

Observations are presented of the formation of annealing twins during the growth of a recrystallized grain into a striated, melt-grown crystal of high-purity lead. The formation of an annealing twin resulted in replacement of the original migrating boundary by a large-angle grain boundary of the caincidence-site type or by a near-twin boundary. The results support the Fullman-Fisher theory of annealing twins and demonstrate the usefulness of the coincidence-site model. FULLMAN and Fisher1 have advanced the following theory to account for the formation of annealing twins during grain growth. Whenever a grain A grows into a matrix of grains S1 and S2, a twin A' of grain A may form, as shown in Fig. 1, if the following energetic condition is satisfied: where "E" and "a" refer to the specific interfacial free energy and the area, respectively, of the boundaries indicated by the subscripts. In effect, the twinned grain will persist when the energy of the boundary between the twin(A') and the matrix grain (S, or S,) is less than that of the boundary between the original growing grain (A) and the matrix grain by an amount which exceeds the energy of the coherent twin boundary between A and A'. Experimental observations on the changes in grain boundary free energy accompanying the formation of twins1 are in agreement with the theory outlined in Eq.[l]. Direct observations of the formation of annealing twins at moving grain corners1"3 and the depend-

Jan 1, 1961

By Graham John Mitchell

In May, 1919, a crosscut on the 1400-ft. level of the Briggs mine, a Calumet, & Arizona property at Bisbee, Ariz., penetrated a deposit of pyrite and chaleopyrite that had replaced quartzite and limestone and was cut, especially in the quartzite, by numerous fractures. As the drift advanced through these fractured portions, they were found to be free from copper-sulfate minerals although '(sooty" chalcocite was present in the fractures and also as coatings and replacements of pyritc. Howcver, sulfate soon made its appearance in certain fractures, filled them, and began to form stalactites. Several centers of incipient growth were noted for subsequent study, observations in the drift at frequent intervals during the past 17 months affording the opportunity of determining the rate of formation of the stalactites. The one to attain the greatest growth during the period of observation measured 27 in. long and averaged 1 in. in diameter. A close study showed it to be composed of small interlocked crystals of chalcanthite radiating from a small central tube-like opening. The trielinic form of the crystals was evident with prism and pinacoid faces recognixable. Assuming that the supply of copper-sulfate solution was constant (luring the 17 months—-and such an assumption is supported by the fact that the number of drops of excess solution falling, per minute, from the tip of the stalactite at the times of observation checked closely—thc stalactite, it has been estimated, grew at the rate of 1.58+ in. per month. DISCUSSION James I?. Kemp," New Yolk City.—J. S. Curtiss, in the monogr:tpll on Eureka, Ncv., say:: that a stalactite formed in limestonc grew 5/8 in. in three weeks and continued to grow as long as it had a drop of water or solution at the lower end. Another grew at the rate of 3/8 in. in the same time. In the case cited by Mr. Mitchell, the growth was about 136 in. in three weeks. A year ago we had an instance of the formation of cubes of galena on a railroad spike. A mine in northeastern Oklahoma had been idle about two years but on account of pumping of neighboring properties, the circulation of water was active throughout the drift. A cube of galena,

Jan 1, 1922

State Mine Experiment Station, College of Engineering, University of Alabama, University, Ala Copies of two bulletins issued by the Mine Experiment Station may be had by writing to the Director of the School of Mmes at the above address: Bulletin 1, Coal losses in Alabama, 2, A specific gravity study of Alabama coals The Cooperative work of the Mine Experiment Station with the Southern Experiment Station of the U S Bureau of Mmes is covered by Bulletins of the U S Bureau of Mines

Jan 1, 1933

By Charles F. King

THE only investigations on record of the reactions occurring during the Bessemer blow are of charges containing a large percentage of manganese, with the exception of two partial analyses by Snelus and Barker of the. English method, where a low percentage of manganese was used. They do not give the analysis of the spiegel, nor do they report any graphitic carbon after the first stage of the process. Both report only traces of manganese after the first stage until the addition of spiegel. The slags corresponding to the samples of metal were not analyzed.

Jan 1, 1881

By S. A. TAYLOR

AN EDITORIAL on the Strike Situation in the Coal mining industry in the New York Evening Post of Nov. 4, 1919, gave what purported to be statistics of the Department of Labor, for a period of two weeks, which showed an average for the year, based on these two weeks, of 32% hours per week. This mode of arriving at the number of hours per week, while not accurate, is not so far off from the facts as to call for any special comment. The report of the U. S. Geological Survey, Department of Coal Statistics, give so the number of days worked in 1917 as 243; reducing the same to hours per week, assuming 8 hours per day, shows a weekly operation of mines at an average of 36J4 hours. But this assumption is not exactly correct, for the reason that it is not very often that the miners work the full 8 hours per day. There are many explanations for this, but it is not pertinent to this statement to discuss them now, as the important thing to consider is whether a 30-hour week would be for the best interest of not only the men themselves, but the public or country in general.

Jan 1, 1920

S., at Niagara Falls, as an expert chemist. There he was engaged in perfect.ing the various kinds of gases, and while thus employed was gassed several times, which so affected his heart and lungs that he was unable to withstand an attack of the influenza which developed into pneumonia, from which he died at the end of 24 hours. He was a member of St. Luke's Episcopal Church, Lebanon, and belonged to the Ancient Accepted Scottish Rite of Freemasonry, Lebanon Lodge 121, I. 0. 0. F. and Camp 65, P. 0. S. of A. Lieutenant Bernhardt Edward Heine Bernhardt Edward Heine, a lieutenant in the Aviation Service of the U. S. Army, died as the result of a fa1I1 in an aeroplane at Fort Sill, Okla., on Aug. 10, 1918. The accident occurred on Aug. 2, when the machine in which he was flying with Lieutenant Carsons fell from a height of 1500 ft.; Lieutenant Carsons was instantly killed, but Lieutenant Heine died from his injuries a week later. Lieutenant Heine was born at Mount Clemens, Mich., in 1895. After attending the local High School he entered the Michigan College of Mines, and became a Junior Member of the Institute while still a student. He graduated in 1916, with the degree of B. S. In 1914 he served as a transitman for the engineering department of the City of Hancock, Mich. Lieutenant Heine had been in the army since 1916, having been with the 'troops at 'the Mexican border. He had been in the Aviation Section since August, 1917.

Jan 1, 1920

By John T., Ryan

THE subject assigned me, "Safety in Mining," is a very broad one and only the high spots can be covered in this short paper. As this is a meeting of the Coal Division, these remarks will be directed largely to coal mine safety, although the principles of safety and effective accident prevention methods are relatively the same in every branch of mining or industrial work. The coal mining industry should take pride in the part it has played in the development of the accident prevention movement, and there is ample proof for the statement that the first real organized accident prevention, work, both abroad and in this country, was con- ducted in the coal mining industry.

Jan 1, 1930

By Donald M. Liddell, G. C. RIDDELL

THE cosmic ray continues to engage the attention of the physicists, and according to Millikan and Compton, experiments of the past summer indicate that these rays must come from interstellar space, but not from the stars themselves. According to press reports of the International Congress of Physicists at Rome, the view was given there that these rays have an initiating potential of over 750,000.000 volts. In the field of spectrographic investigation great strides have been made. The U. S. Naval Research Laboratories (R. F. Mehl and G. E. Doan of Lehigh) have just finished a year's work with a "radium torch" or "shadowgraphic apparatus" in the field of the X-ray, that bids fair to displace the latter to a great extent. The torch is more powerful., easier to operate and cheaper. Penetration of 10 in. of steel has been accomplished, which. is much -beyond the- -scope-, of the X-ray..

Jan 1, 1932

By V. H. Wilhelm

WITH rapidly diminishing oil reserves: a great percentage of which are uneconomical at present prices, some of the existing methods of development and production will have to undergo radical re- visions to meet the changes continually taking place in the petroleum industry. Imagination in an engineer is a great asset. The fancy of today is found to be the realization of tomorrow, and with this thought in mind, there is here presented a more or less imaginative picture which, to my mind, has a meritorious basis. Directed drilling has reached a stage of accuracy sufficient to allow the prediction that this art will be used in the future development of oil structures, especially those \\,it11 thin sand bodies 'and steep dips. Directional drilling in a number of fields in California has gratifying results. Wells which practically laid pipe lines through the oil sands have enjoyed a greater drainage radius with a consequent greater initial and cumulative production. In one field where the vertical thickness of sands was approximately 550 ft., wells drifting at an angle as great as 55 deg. fro111 vertical had over 1100 ft. of perforated pipe in contact with these sands. These wells were, and are, remarkable for their great initial pro-

Jan 1, 1936

By R. W., Ludt

THE use of froth flotation for the separation of minerals has become one of the most important of ore dressing processes. Its particular adaptability to the enrichment of low grade ores has made the process an important factor in the national economy. The methods have been extended to the recovery of a great number of minerals. Among the few minerals which have resisted efforts toward industrial flotation is chrysocolla, a hydrated partly colloidal copper silicate. Chrysocolla, being a product of natural oxidation, has been found to occur in small quantities with many ores which are recovered by flotation methods. In present practice, these small quantities of copper silicate pass off with the tailings and are lost. The advantages to be gained by a satisfactory process for the recovery of chrysocolla is apparent. Any application of principles which points a way toward the satisfactory industrial flotation process for copper silicate would be of advantage. This paper presents an attack on this problem.

Jan 1, 1949

By AIME AIME

THE program of government drilling, conducted jointly by the U. S. Geological Survey and the Bureau of Mines, has demonstrated the presence in Texas and New Mexico of potash-bearing beds of considerable importance. Information regarding the ex- tent and location of the potash deposits as presented at the non-metallic sessions was of great interest to many engineers. These subjects will be covered in greater detail in later paragraphs. The first session, with about 50 in attendance, convened at 10 a.m. on Feb. 18, with Oliver Bowles, chair- man of the Committee on Non-Metallic Minerals, pre- siding. The first paper was on "Soapstone Mining In Virginia," presented by C. W. Ryan of Lynchburg, Va. The nature and extent of the soapstone deposits of Nelson County were described in some detail. In origin, the soapstone is undoubtedly related to a basic peridotite rock though its mode of formation is some- what uncertain. This main soapstone deposit occurs in three veins, the western, middle, and eastern, the middle vein being of greatest economic importance. Methods of stripping, quarrying and milling the rock were described and the uses of soapstone were enum- erated. In discussing this paper, C. P. Berkey, of Co- lumbia University strongly favored the theory of igneous origin of the soapstone and the need for further detailed geological study. J. L. Gillson of Cambridge, Mass., stated that the Vermont and New York talc deposits were always associated with characteristic minerals, such as, a chlorite of one particular variety, siderite, amphibole, magnetite, and biotite. C. H. Behre of Cincinnati, Ohio, raised the question of parallelism in the soapstone structure and Mr. Ryan stated that such parallelism was in evidence in some parts of the deposits. H. A. Wheeler of St. Louis, Mo., also took 'part in the discussion.

Jan 1, 1929

By E. H., Edwerd H. Robie

WILLIAM CHURCH was one of the founders and the first president of the Detroit Copper Mining Co. and was the first man to interest the Phelps Dodge company in the possibilities of the Morenci district, in the '70's. One rather interesting story concerning him is told by James Colquhoun, at one time president of the Arizona Copper Co., in his "History of the Clifton-Morenci Mining District." It seems that a geologist visited the Detroit company's mines and gave Alec McLean, then mine superintendent, quite a lesson on the proper mineralogical terms for what he saw in passing. Later, McLean handed out a few of them to Mr. Church as they walked through the mine on a tour of inspection. The latter had even less regard for a geologist than he did for sulphide ore, which meant little indeed, for in those days the rich ore was all oxidized, and there was no money in the sulphides. So Church was completely unimpressed by the geological and mineralogical terms that McLean had acquired from the visiting geologist. Church turned on him and warned him that so long as he was a member of his staff he was to understand that there were only two kinds of rock in his mines-the one was smelting ore and the other was waste rock, and he was not to forget it.

Jan 1, 1942

By P. H. Brace, N. A. Ziegler

The study of the relations between gases and metals is one of pcren-nial interest to all who are connected with the production of high-grade metallurgical products. The data reported here are the outcome of work of which the object is to determine the effects of dissolved gases upon the properties of metals and to gain a more detailed knowledge of the reactions between gases and molten metals, particularly iron, under definitely controlled conditions. We have attempted to reduce our margin of error by dealing with relatively large quantities of metal, from 4 to 13 Ih. (2 to 6 kg.), and keeping the ratio of refractories to metal as small as practicable. The ingots produced are large enough to provide adequate material for making determinations of magnetic and other physical properties. In choosing the bell-jar type of furnace we were influenced by the results of considerable experimentation along the same general line which indicated that, for the scale on which we were to work, it was important to have the furnace structure independent of the vacuum enclosure. The use of a bell-jar surrounding the entire furnace accomplishes this and also gives great freedom of observation during operation and ready accessibility for the replacements which are necessary after each run. Our choice of analytical method was made in the light of the results secured by H. M. Ryder, who used a method similar in principle for the analysis of very small quantities of gas extracted from strips of metal heated electrically in high vacuum. We have presented some selected preliminary experirnental data as being illustrative of the quantity and nature of the gases which occur in iron of different origins, but do not urgc any hypothesis at this time. The Furnace Our furnace may be described as "a high-frequency induction furnacc of the bell-jar type." It is similar in a general way to that described by Cain and Peterson1 though we have introduced certain refinements of

By Ulick R. Evans

I Should like to commence by saying how much I appreciate the honor which the American Institute of Mining and Metallurgical Engineers has done me in inviting me to visit your country, and to deliver this lecture before you. In choosing a subject, and in deciding what to include and what to omit, I have endeavored to discuss as far as possible work carried out recently in Europe with which you may not be unduly familiar. It would be poor return for your hospitality, and a mistaken sort of compliment indeed, if I were to load the lecture with accounts of researches carried out in your own country—researches with which you are probably better acquainted than I. Not that I have in any way excluded work done on this side of the Atlantic from my survey; one would indeed find it difficult to write on this, or on any other branch of science, without mentioning American work. But I have endeavored as far as possible to concentrate on aspects of the case which will, I hope, be comparatively fresh to you, and I feel fairly certain that this will be in accordance with your own wishes. Films Produced at Elevated Temperatures If a strip of iron is heated strongly at one end, the other end remaining cold, there is produced over the heated portion a layer of oxide scale, the thickness of which diminishes steadily with the distance from the hot end. Somewhere in the middle of the strip, the thickness of the oxidized layer will become comparable to the wave length of light, and over this region the thin films give rise to a series of beautiful interference tints, commonly known as "temper colors." The colors are caused by the fact that two trains of light waves are reflected respectively from the outer and inner surfaces of the oxide film, and the possibility arises that the "crests" of one series of waves may coincide with the "troughs" of the other, thus diminishing the intensity of the light of some particular wave length. The state of affairs in this part of the strip is shown diagrammatically in Fig. 1, in which the film thickness is enormously exaggerated, of course, in comparison with the length of the strip; the

Jan 1, 1929