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By W. K. Hartley

INTRODUCTION AND HISTORY The Kimberley Division of De Beers Consolidated Mines Limited includes four underground mines in Kimberley viz. Dutoitspan, Bultfontein, De Beers and Wesselton Mine and two outside mines, viz. Finsch, an opencast operation and Koffie- fontein, an underground operation. Figure 1 is a map of the Kimberley district showing the location of these mines. Finsch is 150km west of Kimberley and Koffiefontein is 80km south of Kimberley. The head office of the De Beers Company is in Kimberley. The diamond sorting and trading companies for diamonds produced in South Africa are also in Kimberley. Diamonds were first discovered in the Kimberley area at Hopetown in 1866 on the banks of the Orange River. This, and later finds, triggered the start of the great "Diamond Rush". In 1870 the Jagersfontein (now closed) and Dutoitspan pipes were discovered, followed by those at Bultfontein, De Beers and Kimberley Mine (now closed) in 1871, Koffiefontein in 1880 and Wesselton in 1891. Finsch Mine was a more recent discovery in 1961. Finsch, due to go underground in 1986, and Koffiefontein, are fully self-contained with their own treatment plants, housing, services etc. The four Kimberley mines deliver ore by conveyor to a central treatment plant and use joint ser- vices. ,+lining is presently carried out mainly by Block Caving which has replaced the earlier Chambering method. De Beers Mine, on a limited scale, and Wesselton Mine have recently started to use Sub-Level Caving, and both Bultfontein and Du- toitspan are scheduled to use the same method at a later date. The combined ore tonnage produced by the Kimberley Mines is 17 400 tons per day, Koffiefontein 12 000 tons per day and Finsch Mine 17 000 tons per day. THE EVOLUTION OF MINING METHODS Initially, the open-cast mining was carried out to as great a depth as safety would permit. In the early stages of open-cast mining, the Kimberlite was removed in horizontal slices from levels 13m to 20m apart. The rock broken in the workings was raised to the surface by means of endless rope haulage inclines. As lower levels were attained these rope haulages were replaced by aerial hoists, inclined shaft haulages or inclined skip-ways. These methods were dependent upon the strength of the unsupported pipe walls, which became increasingly unstable with depth and a system was adopted whereby the ground mined in open excavations was tipped down passes to tunnels connecting with vertical hoisting shafts sunk in the country rock. As work in the open pit became more and more impracticable due to extensive falls of ground, this system was replaced by a combination of open-cast and underground mining, and eventually by wholly underground methods. Chambering With the advent of underground mining, a system known as "Chambering" (or "Inclined Chambering") was evolved. It was essentially a combination of shrinkage stoping and caving, whereby advantage was taken of the high pressure exerted by the loose rock that had accumulated in the open excavations due to the collapse of the pipe walls. This mining method was introduced around 1890 and was successfully employed, with little change, up to the early nineteen seventies. In this system each mine was served by a main hoisting shaft situated about 300m in the country rock. Main haulage cross cuts were driven from the shaft to the pipe at 200m (600ft) vertical intervals. A sub-vertical shaft, situated close to the pipe provided access to the working levels. Chamber levels were established from the sub-vertical shaft at 13m (40ft) intervals. See figure 2. On each of these levels successive 6,8m wide “cuts" were mined out across the pipe, from one rock contact to the other, and extended vertically to the footwall of the level above. Every 6,8m cut was made up of a chamber and a "back-pillart1, each approximately 3,401 wide. The chamber was mined by overhand shrinkage stoping. The levels were carried "en echelon", with each chamber on a level approximately three cuts ahead of the chamber on the level

Jan 1, 1981

By L. A. Willey

Although the interierometric method for the determination of length changes was devised by Fizeau more than three quarters of a century ago, it has not achieved the widespread use in the metallurgical field that its precision and simplicity would seem to warrant. The interferometer and the basic principle are both very simple. When optically plane surfaces held at a very slight angle to each other are illuminated by monochromatic light, rectilinear, equally spaced interference fringes arc formed. Each fringe corresponds to a defiuitc thikness of the wedge formed by the optical flat.;. The difference in wedge thickness between two consecutive fringes is cqual to one half the wave length of the illuminating light. Instruments for vicwing the intertero~ncter have passed through a number of modifications. Outstanding among the improvements were those Abbe. in 1884. His improved instrument permitted micrometric mcasurements to the order of one-hundredth of the width of an interference fringe (i.e., lengths were measured to the order of one two-hulldredth of the mave length of light ). It also permitted the consecutive use of light of several wave lengths. which made possible the determination of the order number of any fringe and therefore the absolute thickness of the wedge at any point. The Abbe dilatometer and methods of measuretment, including corrections to he applied for the change of index of refraction with change in tempcrature and barometric pressure in an air wedge, have been thoroughly described by Pulfrich.' Pulfrich2 made further improvements in the interference measuring apparatus. His instrument embodied all the features of the Abbe dilatometer but was made more versatile by its complete mechanical separation from the interferorneter. The introduction of an Amici prism in the piece permitted the simultaneous observ tion of the whole set of fringe systems developed in the interferometer from the visible light of a geisler tulle. .Also, the introduction of a direct-vision, reflecting prism made it possible to set the fringes parallel to the two vertical fiducial line. of the instrument without the necessity of rotating the interierometcr. Interferometric methods employed ill this country have been developed and dcscribed by Priest, Pelers and Cragoe," Austin,5 Merritt,= Saunders,? and Nix and MaNair. Since none of these authors used the type of instrument that was employed in the present investigation, they Will not be discussed here. This paper will be limited to the description of the interfernmetric apparatus and method used at the Aluminum Research Laboratories and to the presentation of data so obtained. Apparatus and Procedure A general view of the dilatometer, not including equipment for controlling and

Jan 1, 1945

By D. K. Crampton, H. l. Burghoff, J. T. Stacy

The study of copper alloys of the age-hardening type has received considerable attention, and, among the alloys which the authors have, considered, those containing small amounts of nickel and phosphorus as essential constituents seem especially interesting. Such alloys have attractively great capacity for being hardened and also have relatively high electrical and thermal conductivity in the hardened state. In addition, it has been found that the increase in hardness and strength imparted by aging can be greatly augmented by cold-working, so that excellent combinations of conductivity and strength are obtainnble. In view of the possible importance of the alloys, it was considered desirable to investigate the solubility relationships in the copper-rich portion of the copper-nickel-phosphorus system. This paper present's some of the results obtained in this investigation to date and also gives propertics of typical alloys that appear to be of commercial interest,. Review of literature Copper-nickel System,.—The binary coppcr-nickcl system has long been known to consist of a series of simple solicl solutions, copper and nickel being miscible at all tempcrat'ures and concentrations. This was establisl~cd by Guertler arid Tammannl in 1907 and confirmed by Tafel2 in 1908. Copper-phosphorus System.—The copper phosporus system has been studied by numerous investigators, so that the copper-rich portion is now definitely known. As most recently determined by Lindlief," his system has a cutectic at 8.38 per ccnt P, cuteetic temperature being 714° C. Components of the cutectic are Cu3P and alpha solid solution. Solid solubility of phosphorus in copper, according to Mertz arid Mathewson decreases from a maximum of about 1.75 per cent at 714' C. to about 0.6 per cent at 300' C.

Jan 1, 1940

By D. K. Crampton, H. l. Burghoff, J. T. Stacy

The study of copper alloys of the age-hardening type has received considerable attention, and, among the alloys which the authors have, considered, those containing small amounts of nickel and phosphorus as essential constituents seem especially interesting. Such alloys have attractively great capacity for being hardened and also have relatively high electrical and thermal conductivity in the hardened state. In addition, it has been found that the increase in hardness and strength imparted by aging can be greatly augmented by cold-working, so that excellent combinations of conductivity and strength are obtainnble. In view of the possible importance of the alloys, it was considered desirable to investigate the solubility relationships in the copper-rich portion of the copper-nickel-phosphorus system. This paper present's some of the results obtained in this investigation to date and also gives propertics of typical alloys that appear to be of commercial interest,. Review of literature Copper-nickel System,.—The binary coppcr-nickcl system has long been known to consist of a series of simple solicl solutions, copper and nickel being miscible at all tempcrat'ures and concentrations. This was establisl~cd by Guertler arid Tammannl in 1907 and confirmed by Tafel2 in 1908. Copper-phosphorus System.—The copper phosporus system has been studied by numerous investigators, so that the copper-rich portion is now definitely known. As most recently determined by Lindlief," his system has a cutectic at 8.38 per ccnt P, cuteetic temperature being 714° C. Components of the cutectic are Cu3P and alpha solid solution. Solid solubility of phosphorus in copper, according to Mertz arid Mathewson decreases from a maximum of about 1.75 per cent at 714' C. to about 0.6 per cent at 300' C.

Jan 1, 1940

By Leon Dominian

Page I. Introduction......................237 11. Coal..................239 (a) Western Asia Minor.........239 I-. Lignites of the Marmora-Bgean zone.239 2. The Black Sea basin.............241 (b) Eastern Asia Minor..........244 (c) Syria................246 (d) Mesopotamia................ 246 (e) European Turkey.'.....'..... 247 111. Oil and Allied Hydrocarbons...............248 (a) Early Use of Oil and Bitumen in Turkey........248 (b) Syria........................ 250 (c) Mesopotamia.................... 250 (d) European Turkey.................. 256 I. INTRODUCTION Apart from local needs in the country's development, the interest attached to Turkish fuels grows chiefly out of the importance of the railway industry in Asiatic Turkey. Geographical conditions make of the tracks in this region the most essential link in a chain of world-girdling lines. By its position Asia Minor can be likened to a bridge in the through routes destined to connect European factories with Asiatic and African markets. An uninterrupted right-of-way from points in central Europe to populous Indian cities must necessarily pass through the valleys of Anatolia. Crossing thence the Taurus Mountains, its natural passage is indicated as the Mesopotamian lowland and the shores of the Indian Ocean. Similarly, land connection between Europe and Africa can be obtained only by passage through Asia Minor, Syria and Palestine. The occurrence of fuel within an area of such significance from the

Jan 1, 1917

By C. M. Marquardt

Tramp iron and steel moving on a conveyor belt cause small currents to be generated in a coil situated in a strong magnetic field, which are converted to an alternating current and are amplified. The output voltage from the amplifier fires a thyratron with a relay in its anode circuit, which actuates a howler and simultaneously drops a spot of marker material on the belt.

Jan 6, 1950

By Henry F. Heblby

HOW often has the thoughtful observer pondered the apparent contradictions experienced in the weather? One can take records of two days, one in the winter and one in the summer. The "degree days1' indicate that space heating and domestic load were present in one case and not in the other. The Business Index may be about the same, indicating that the industrial activity of the area and its concomitant use of fuel were about the same. Thus the volume of the products of combustion released to the atmosphere varied only as related to the space heating demand. Yet on one day in winter the atmosphere may be clear and bracing, while on a summer's day the air is thick and murky and the visibility sharply reduced. The situation may be reversed. What are some of the factors that contribute to the creation of these conditions? These few notes have been prepared to indicate some of the influences that are exerted on the problem. The Sources of Atmospheric PolLution The industrial area of Pittsburgh, Pa., has been a dominant center for the production of iron and steel for over one hundred years. In fact, with the growth of the numerous auxiliary processes Allegheny County which contains Pittsburgh is prob- ably the most industrialized county in the world. In addition, the type of manufacture carried out in this area is predominantly dependent on thermal energy (heat). That energy is supplied from coke and coal produced in the vicinity of Pittsburgh Indicative of the stupendous quantities of fuel that are employed in this industrial area's economy, the following (Table I) taken from the U. S. Census (1940) may be of interest. In tonnage consumed in the area, the figures are equally impressive: Annual Tons oF Coal Metallurgical Industries.... 35,000,000 to 40,000,000 Commercial Installations (Pgh.)................. 1,500,000 Domestic hand-fired) (Pgh.)................. 750,000 An influence that has never been fully appreciated by many individuals is the fact that no matter what adventures the gases of combustion experience as they pass through the various processes, uti-mately the spent gases are discharged through chimneys to the atmosphere.

Jan 1, 1949

By H. R. Nelson, Martin S. Maier

The diffusion of metals plays an important role in many metallurgical processes,lJ as, for example, the formation of alloys by the annealing of mixed powders, the homogenization of segregated alloys, and the carburization of steel. Other equally important phenomena, such as recrystalli-zation and creep, are based on the movement of like atoms. Although much is known concerning the effects of diffusion in metals, very little is known concerning the details of the physical processes involved. 1,3-5 The data that should give most information concerning the processes involved in diffusion are those on the diffusion of like atoms—self-diffusion. Very little is known concerning the rates of self-diffusion of metals because before the discovery of artificial radioactivity in 1934 there was no means of detecting the movement of the diffusing atoms through the solvent metal except in the elements possessing natural radioactive isotopes—lead, thallium and bismuth. Using the induced radioactivity of the element as an indicator, atoms can now be "tagged" so that the rate of diffusion of the radioactive isotopes of an element (tagged atoms) into the stable isotopes of the same element can be measured. As the radioactive and stable isotopes of an element differ only in nuclear structure, it is quite certain that all isotopes of an element diffuse at the same rate. Two techniques have been used to measure self-diffusion. In one, a thin layer of radioactive metal is deposited on the face of the solvent metal, and the decrease in the surface activity as the radioactive atoms diffuse into the solvent metal is measured. This method has been used to determine the coefficients of self-diffusion of lead6-l0 and bismuth10 using natural radioactive isotopes, and of gold1' and copper12 using artificial radioactive isotopes. In the other technique a thin layer of the radioactive metal is deposited oil one face of the solvent metal, and after diffusion has occurred the specimen is cut in thin sections to obtain the concentration-penetration curve. This method has been used to determine the coefficients of self-diffusion of gold,13 zinc,14-l6 silver," and copper.17 The second method was used for the work described in this paper. Materials The coefficients of self-diffusion were determined in two grades of polycrystalline copper and in single crystals of copper. Commercial OFHC copper was used in the form of disks I in. in diameter by % in. thick. Samples of high-purity copper described by Phillips and Skinnerl9 were supplied through the courtesy of the American Smelting and Refining Co. The high-purity copper rod was used without remelting by cross-rolling to a thickness of 0.075 in., from which disks 7/8 in. in diameter were cut. A good grade of bus-bar copper was used to make the single crystals.

Jan 1, 1942

By Martin S. Maier, H. R. Nelson

The diffusion of metals plays an important role in many metallurgical processes,lJ as, for example, the formation of alloys by the annealing of mixed powders, the homogenization of segregated alloys, and the carburization of steel. Other equally important phenomena, such as recrystalli-zation and creep, are based on the movement of like atoms. Although much is known concerning the effects of diffusion in metals, very little is known concerning the details of the physical processes involved. 1,3-5 The data that should give most information concerning the processes involved in diffusion are those on the diffusion of like atoms—self-diffusion. Very little is known concerning the rates of self-diffusion of metals because before the discovery of artificial radioactivity in 1934 there was no means of detecting the movement of the diffusing atoms through the solvent metal except in the elements possessing natural radioactive isotopes—lead, thallium and bismuth. Using the induced radioactivity of the element as an indicator, atoms can now be "tagged" so that the rate of diffusion of the radioactive isotopes of an element (tagged atoms) into the stable isotopes of the same element can be measured. As the radioactive and stable isotopes of an element differ only in nuclear structure, it is quite certain that all isotopes of an element diffuse at the same rate. Two techniques have been used to measure self-diffusion. In one, a thin layer of radioactive metal is deposited on the face of the solvent metal, and the decrease in the surface activity as the radioactive atoms diffuse into the solvent metal is measured. This method has been used to determine the coefficients of self-diffusion of lead6-l0 and bismuth10 using natural radioactive isotopes, and of gold1' and copper12 using artificial radioactive isotopes. In the other technique a thin layer of the radioactive metal is deposited oil one face of the solvent metal, and after diffusion has occurred the specimen is cut in thin sections to obtain the concentration-penetration curve. This method has been used to determine the coefficients of self-diffusion of gold,13 zinc,14-l6 silver," and copper.17 The second method was used for the work described in this paper. Materials The coefficients of self-diffusion were determined in two grades of polycrystalline copper and in single crystals of copper. Commercial OFHC copper was used in the form of disks I in. in diameter by % in. thick. Samples of high-purity copper described by Phillips and Skinnerl9 were supplied through the courtesy of the American Smelting and Refining Co. The high-purity copper rod was used without remelting by cross-rolling to a thickness of 0.075 in., from which disks 7/8 in. in diameter were cut. A good grade of bus-bar copper was used to make the single crystals.

Jan 1, 1942

THE Searles Lake orebody is located in the north- west corner of San Bernardino County. It is a dry lake bed with an exposed salt surface covering an area of 12 square miles. Recoverable mineral values are contained in the mother liquor below the surface of the lake. Stratification in the lake bed has separated the brine into two bodies which differ in composition. Although liquor is processed from both bodies, this paper will discuss only the upper structure brine. Fig. 1 illustrates a typical cross-section of the two commercial orebodies. The orebody is composed of a porous salt deposit 70 to 90 ft deep. The upper structure is separated from the lower orebody by a 12 to 16-ft thick impervious mud seam, as shown in Fig. 1. These salt structures are composed of 55 pct solid-phase salts and 45 pct voids which are filled with the original mother liquor.

Jan 2, 1954

By R. Schumann

THE expression "unit process " comes up with increasing frequency in discussions among metallurgists and mineral engineers, especially among those concerned with training the next generation. The unit process approach characterizes a significant advance along the road from metallurgy as an empirical art to metallurgy as a branch of engineering. The purposes of this paper are to define and list the unit processes in specific terms, to indicate the scientific and engineering principles basic to all the unit processes, and finally to show how these ideas have been applied to a reorganization of instruction in chemical metallurgy. UNIT OPERATIONS AND UNIT PROCESSES Metals are extracted from ores and other raw materials by stepwise procedures. In general, each metallic element is extracted by a different procedure. For many of the metals there is a choice of several flowsheets. However, the procedures all have steps in common. In fact, the many different flowsheets are all made up of a relatively small number of steps which are combined in different groups and sequences. For example, crushing, screening, roasting, sintering, melting, and gaseous reduction are steps which each appear in the flowsheets for extracting the majority of the metals. The individual steps or flowsheet units can be designated as unit operations or unit processes. These terms are well established in the field of chemical engineering, as the American Institute of Chemical Engineers' definition of chemical engineering shows: " Chemical engineering is that branch of engineering concerned with the development and application of manufacturing processes in which chemical or certain physical changes of materials are involved. These processes may usually be resolved into a coordinated series of unit physical operations and unit chemical processes. The work of the chemical engineer is concerned primarily with the design, construction, and operation of equipment and plants in which these unit operations and processes are applied. Chemistry, physics, and mathematics are the underlying sciences of chemical engineering, and economics its guide in practice."1a In this definition, the distinction between unit operations and unit processes is that the unit operations are physical while the unit processes are chemical. Table I gives a list of the principal unit operations and unit processes of chemical engineering, taken from Shreve. lb Table 2 lists the principal unit operations and unit processes used for metal extraction. The division between unit operations and unit processes is similar to the chemical engineers' distinction and also corresponds approximately to the division of labor between mineral dressing and chemical metallurgy which has been customary in the past. Furthermore, it will be noted that in the proposed classification the unit processes primarily involve chemical reactions and/or changes in state of aggregation; the unit operations, primarily do not involve either bulk

Jan 1, 1948

Extremes in temperature and weather, along with the highly corrosive nature of acid leach solutions used at open-pit copper mines, necessitates the use of pipeline systems that are both corrosion resistant and impervious to the environment.

Jan 6, 1976

By AIME AIME

MATTERS pertaining to mine ventilation were, taken up at the annual meeting Wednesday morning with E. A. Holbrook in the chair. In the absence' of its author, G. E. McElroy, the first paper, entitled "Economic Size. of Metal Mine %Airways," was read by title by the chairman. The second paper, "Intermittent Mine Ventilation," by Oscar A. Glaeser, was 'abstracted by Dan Harrington. It related to metal-mining practice, being inapplicable to coal mining, of course. B. F. Tillson asked how the ,quantity of air was measured and con- trolled in the different splits and Mr. Harrington stated that an anemometer presumably was used and that split- ting was controlled by adjusting the steel doors to the desired position by means of screws. George 'S. Rice asked if the fan were underground, and Mr. Harrington replied that it was. Although he had at, one time recommended that it be placed' on the surface, certain factors led the management to keep it underground, a. location that has several advantages in this particular case.

Jan 1, 1932

By George Young

DURING the spring of 1910 I visited a number of open-pit brown-coal mines and underground workings in the vicinity of Halle, Halberstadt, Leipsic, Cologne and Bonn. The notes which I took and the observations which I made at the time have been condensed and make up the principal part of this paper. Certain supplementary information has been taken from several sources which are given in the paper. The mining of brown coal is one of the important industries of Germany. The coal varies in color from dark brown to almost black and is soft like loam. Pieces of wood and strips of bark and, even parts of tree trunks are frequently encountered in the excavation although the coal for the most part consists of a pulverulent, more or less matted mass of small particles of vegetal matter. It is a product between peat and lignitic coal. An analysis, taken from Coal Resources of the World shows the approximate composition of the material: Moisture, 53.73 per cent.; ash, 4.98; fixed carbon, 18.08; volatile carbon, 23.31 per cent. The principal characteristic is the amount of moisture. This seldom runs less than 48 per cent. The ash is usually low and ranges from 5 to 10 per cent. The sulphur content is usually less than 0.5 per cent. The heating effect of the fuel ranges from 2,000 to 2,500 calories.

Jan 2, 1916

By D. R. Mitchell

MEETING for the thirteenth time in New York as part of the five-ring circus known as the Annual Meeting A.I.M.E., the Coal Division experienced a wartime boom in attendance. Technical sessions were crowded and whereas 65 seats were set up for the annual luncheon meeting of the Division over 100 members showed up, many of whom had to be fed elsewhere. Possibly the Coal Division should adopt "13" as its lucky number. Discussions at technical sessions, formal and informal, were lively. Those papers containing material directly concerned with the war, or containing information that might be usable for war industries, were enthusiastically received. Some criticism was made in regard to the present method of handling discussions and it was suggested that better success would be had in getting discussions in the record by the use of hired reporters. This is being considered by the executive committee of the Coal Division.

Jan 1, 1943

By Joseph P. Brennan, Robert L. Vines

A historical comparison of the frequency of fatal coal mining accidents occurring underground in mines of various size ranges in the United States and in member countries of the Commission of the European Communities is presented. Frequencies are normalized on hours-worked and tons-produced bases. The comparisons rely on published and confirmed data and on theory for selective treatment of data in an effort to overcome reporting differences and basic differences in the mining conditions and system employed. Trends are identified ad projections made of the effect on accident records of various industry growth patterns. Conclusions are drawn regarding the reasons for differences between the records of U.S. underground coal mines and the records of those mines in European countries.

Jan 1, 1984

APPROXIMATELY 90 per cent of the steel that is melted and refined in the United States and poured into ingots is made in basic open-hearth furnaces, as shown in Table 1-1. The annual ingot capacity of the steel industry reported January 1,1950, by the American Iron and Steel Institute8* was 99,040,160 tons, of which the basic open-hearth process accounted for 85,896,580 tons, 86.7 per cent of the total. The capacity of the individual furnaces varies over a wide range, a large majority falling within limits of 50 to 200 tons (Fig 1-1). Most of the units constructed [ ] since 1942 are in the larger size groups, between 175 and 225 tons capacity.

Jan 1, 1951

By T. A. Wilson, S. L. Hoyt

THE plastic deformation of slender single crystals of zinc has been described in some detail in the paper by Mark, Polanyi and Schmid,1 which has become a classic, and also by one of the present authors in a somewhat shorter account.' The study of single-crystal zinc is termed classical because zinc single crystals offer, perhaps, the best material yet available for the study of atomic behavior during deformation and the effect known as "strengthening" in metals. A considerable amount of additional work has also been done on single-crystal zinc, but as it is not closely related to the present paper it will not be considered. Throughout all the former work, the mechanism of plastic deformation first described by Mark, Polanyi and Schmid has been assumed to hold. This may be said to offer the strongest confirmation of its correctness. Even so, the picture of the process has never been as completely portrayed as is desirable. The first object of the present paper is to describe work that has been done in this field, and which is even yet being carried on, in the hope that a more complete picture may be obtained. Mathewson and Phillips' have recently described a new mechanism of the deformation of zinc based on their study of large rectangular crystals. One of their conclusions was that deformation produced twinning with a rotation of some of the basal planes into positions 94° removed from their original position; a position almost the same as that of the prismatic planes before twinning. A second conclusion was that fracture occurred along these basal planes in their new position, and, therefore that fractures previously regarded as prismatic were in reality basal. Such findings are of great significance and they raise a question as to the generality of such behavior. Professor Mathewson's opinion is that even the slender cylindrical single crystals behave in the same manner as his large rectangular crystals when strained by simple tension.

Jan 1, 1928

By Charles H. Snow

In vol. xxxviii. (1889) of the American Journal of Science, under the heading " Pseudomorphs of Native Copper after Azurite from Grant County, New Mexico," Mr. W. S. Yeates describes a most interesting mineral form. His account is, that a material having the appearance of native copper, but brittle and much lighter than native copper (its specific gravity being but 4.15), was submitted to him by the United States National Museum for examination. The substance was reported to him as occurring in masses, varying in weight from one ounce to seventy pounds, and composed of tabular crystals, variously grouped. The specimens, when submitted, ex hibited on the outride a covering of clay; and they were subse quently found to consist of particles of the same clay, intimately mixed with others of native copper, producing the aspect, without the weight, of pure copper. The forms of the azurite crystals, found at Bisbee, Arizona, having been suggested by the specimens, actual goniometer-measurements were made; and the two crystallizations were thus proved to be identical. To these statements I may be permitted to add some further in formation, derived from personal examination, and illustrated with a suite of characteristic specimens collected by myself (Fig. 2).* Grant County, New Mexico, in which these specimens were found, is a region noted for variety of mineral species. The sixth edition of Dana's Mineralogy mentions many of the silver, copper, and lead minerals, and also turquois, aragonite, wulfenite, barite, fluorite, vanadinite, etc. I have noticed also green and red garnet, molybdenite, native alum, smithsonite, bornite, etc., some of which presented peculiar modes of occurrence. The green garnet, for instance, was in masses formed of separate crystals, each of pea-size and not unlike that vegetable in tint and smooth opaqueness. The crystallization was

Jan 1, 1893

By P. Breidt, E. S. Greiner

THIS note reports a determination of the melting point of germanium, and the liquidus of the Ge-Ga alloys; lattice constants of the a phase are given. The alloys were prepared by melting germanium (>20 ohm-cm resistivity) and gallium (99.6 pct) in evacuated silica tubes. The materials (50 to 70 g) were heated at 1000°C, held in the liquid state for about ¾ hr, and then cooled rapidly in the tubes. Points on the liquidus were obtained by thermal analysis which consisted of obtaining time-temperature data during heating and cooling the materials in high purity graphite crucibles and a helium at- mosphere. Temperatures were determined with a Pt—Pt-Rh thermocouple protected by a silica sheath. The couple was calibrated against a National Bureau of Standards calibrated couple and also against the freezing points of copper, silver, aluminum, and the 28.1 wt pct Cu, 71.9 wt pct Ag alloy eutectic. The samples for X-ray analysis were prepared by heating small pieces of the ingots in evacuated glass or quartz tubes at temperatures between 600" and 900°C for periods ranging from 2 hr to 22 days, periods deemed sufficient for equilibrium to be attained, followed by quenching in water. The heat-treated samples were ground to powder for X-ray analysis. The lattice constants of the germanium-rich phase (a) were determined with a baok-reflection focusing camera. The X-ray reflections (331 and 422 Cr Ka, 422 and 333 Cr KB) were corrected

Jan 1, 1956