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United Engineering Trustees, Inc. H. G. MOULTON, 40 A. L. QUENEAU, '38 ALBERT ROBERTS, '39 The Engineering Foundation GEORGE D. BARRON, '40 A. L. QUENEAU, '38 Engineering Societies Library Board H. K. MASTERS, '38' A. B. PARSONS, Ex-officio F. F. SHARPLESS, '37

Jan 1, 1936

By G. L. F. Powell

g samples of Cu-20 wt pct Ag alloy have been mdercooled to a maximum of 197°C by melting under a slag of commercial soda-lime glass in a vitreous silica crucible. No grain refinement of the primary copper was observed in samples undercooled to the maximum of 197°C. When the samples contained a small amount of oxygen, the copper dendrites were partially recrystallized at undercoolings greater than 97°C. In previous papers'-3 reporting the grain structure of undercooled silver and copper, it was observed that grain refinement was dependent on both undercooling and oxygen content. Grain refinement occurred in undercooled silver when the degree of undercooling exceeded the range 153" to 175"C, while in Ag-0 alloys (0.12 wt pct) fine equiaxed grains were exhibited when undercooling was greater than 50°C. Similarly, copper samples undercooled as much as 208°C displayed fan-shaped growth from a single nucleation site, while the grain structure of Cu-O alloys (0.08 wt pct) was fine and equiaxed at undercoolings larger than 150°C. Thus the presence of oxygen greatly reduced the undercooling at which grain refinement occurred. It was also observed that the change in grain size resulted from recrystallization and was not due to an enhanced nucleation rate in the liquid-solid transformation. It is possible that the influence of oxygen on recrystallization is due primarily to its presence as a solute element. walker4,' reported that, although a grain size change did not occur in pure nickel until the undercooling exceeded 150°C, small grains were observed in samples of Ni-Cu alloy solidified at small and large degrees of undercooling. Jackson et al.6 suggested that the fine grained structure of the Ni-Cu alloy resulted from the melting off of dendrite arms during recalescence. This remelting process may occur in alloys as a result of segregation during freezing which causes a variation in liquidus temperature from point to point within a dendrite. It was therefore decided to undercool copper with a metallic alloying element to ascertain whether the presence of a metallic solute would have a similar effect to oxygen in inducing grain refinement. A Cu-Ag alloy was chosen, since both metals had been shown to behave similarly on undercooling. The alloy Cu-20 wt pct Ag was selected since the eutectic constituent outlines the initial growth form of the primary copper, so that the as-frozen grain structure is not obscured if subsequent recrystallization occurs. This paper describes the results of undercooling experiments carried out with Cu-20 pct Ag samples undercooled to a maximum of 197°C and the effect of oxygen content on the grain structure of the undercooled samples. EXPERIMENTAL Melting was carried out in a small cylindrical resistance furnace using "fine" silver granulate and oxygen-free high conductivity copper. The procedure adopted was to melt the required quantity of silver in air in a clean vitreous silica crucible for approximately 15 min, freeze, and add granulated commercial soda-lime glass to form a complete surface slag cover, after which the sample was melted and frozen several times to reduce the oxygen content. The glass slag cover was approximately 3 in. thick. Pieces of copper (=50 g) were added to the crucible until the required quantity to make 350-g samples of alloy had been charged. Each piece was added quickly to the crucible which was held at a temperature slightly above the melting point of silver. The piece was quickly pushed beneath the glass to minimize oxidation and any oxide coating usually decomposed before the piece had settled down into the silver. After the full quantity of copper had been added, the melt was stirred with a silica rod to hasten homogenization and a Pt/Pt 13 pct Rh thermocouple enclosed in a vitreous silica sheath inserted for temperature measurement. Heating and cooling curves were recorded on a potentiometric chart recorder fitted with a zero suppression unit. The milli-voltage range of the recorder was adjusted so that temperatures could be read to 1°C. Heating and cooling curves were taken every hour until three consecutive readings gave the same solidus-liquidus range, consistent with the solidus-liquidus range for this alloy composition by reference to Hansen and Anderko.7 Metallographic examination of samples frozen at this stage, failed to show any variation in composition from bottom to top of the ingot. Consequently, it was considered that the melt was homogeneous at this stage and undercooling experiments were then car-

Jan 1, 1970

New York Meets first Wednesday after first Tuesday of each month. DAVID H. BROWNS Chairman. JOHN H. JANEWAY, Vice-Chairman. F. E. PIERCE, Secretary 35 Nassau St., New York, N. Y. P. A. MOSMAN, Treasurer. LEWIS W. FRANCIS. BENJAMIN B.. LAWRENCE. Boston Meets first Monday of each winter month. HENRY L. SMYTH, Chairman. ALFRED C. LANE, Vice-Chairman. HENRY A. WENTWORTH, Secretary-Treasurer, 60 India St., Boston, Mass. A. H. EUSTIS, F. G. STANTIAL. Columbia Holds four sessions during year. Annual meeting in September or October. STANLY A. EASTON, Chairman. FREDERIC KEFFER, Vice-Chairman. LYNDON K. ARMSTRONG, Secretary-Treasurer, P. O. Drawer 2154, Spokane, Wash. D. C. LIVINGSTON, FRANK A. ROSS.

Jan 5, 1916

New York Meets first Wednesday after first Tuesday of each month. DAVID H. BROWNE, Chairman, JOHN H. JANEWAY, Vice-Chairman. F. E. PIERCE. Secretary, 35 Nassau St., New York, N. Y. P. A. MOSMAN, Treasurer. LEWIS W. FRANCIS. Boston Meets first Monday of each winter month. HENRY L. SMYTH, Chairman. ALFRED C. LANE, Vice-Chairman. HENRY A. WENTWORTH, Secretary-Treasurer, 60 India St., Boston, Mass. ROBERT H. RICHARDS, ALBERT SAUVEUR. Columbia Holds four sessions during year. Annual meeting in September or October. FRANK A. ROSS, Chairman. RUSH J. WHITE, Vice-Chairman. LYNDON K. ARMSTRONG, Secretary-Treasurer, P. O. Drawer 2154, Spokane, Wash. FREDERIC KEFFER, FRANCIS A. THOMSON.

Jan 8, 1915

EXECUTIVE COMMITTEES OF LOCAL SECTIONS New York Meets first Wednesday after first Tuesday of each month. DAVID H. BROWNE, Chairman, JOHN H. JANE WAY, Vice-Chairman. F. E. PIERCE, Secretary, 35 Nassau St., New York, N. Y. P. A. MOSMAN, Treasurer. Boston Meets first Monday of each winter month. HENRY L. SMYTH, Chairman. ALFRED C. LANE, Vice-Chairman. HENRY A. WENTWORTH, Secretary-Treasurer, 60 India St., Boston, Mass. ROBERT H. RICHARDS, ALBERT SAUVEUR. Columbia Holds four sessions during year. Annual meeting in September or October. FRANK A. ROSS, Chairman. RUSH J. WHITE, Vice-Chairman. LYNDON K. ARMSTRONG, Secretary-Treasurer, P. O. Drawer 2154, Spokane, Wash. FREDERIC KEFFER, FRANCIS A. THOMSON.

Jan 6, 1915

New York Meets first Wednesday after first Tuesday of each month. . DAVID H. BROWNE, Chairman. JOHN H. JANEWAY, Vice-Chairman. . F. E. PIERCE, Secretary, 35 Nassau St., New York, N. Y. P. A. MOSMAN, Treasurer. LEWIS W. FRANCIS. BENJAMIN B. LAWRENCE. Boston Meets first Monday of each winter month. HENRY L. SMYTH, Chairman. ALFRED C. LANE, Vice-Chairman. HENRY A. WENTWORTH, Secretary-Treasurer, 60 India St., Boston, Mass. A. H. EUSTIS, F. G. STANTIAL. Columbia Holds four sessions during year. Annual meeting in September or October. STANLY A. EASTON, Chairman. FREDERIC KEFFER, Vice-Chairman. LYNDON K. ARMSTRONG, Secretary-Treasurer, P. O. Drawer 2154, Spokane, Wash.

Jan 2, 1916

By L. F. Reinartz

FROM the earliest times when our prehistoric ancestors laboriously fashioned crude tools and weapons from meteoric iron until our day when we manufacture steel in 150-ton open-hearth furnaces, the production of iron and steel has played a dramatic and important role in the development of civilization. Progress in the science of refining iron ore into iron and steel was painfully slow for many centuries. The keen scimitars of Damascus, the broadswords of the English knights, the coats of mail of French knights, and the Iron Pillar of Delhi are well¬known examples of medieval metallurgical technique. Expense and the scarcity of raw materials originally limited the distribution of iron and steel products. It was not until the nineteenth century that a determined effort was made to adapt the use of steel to peaceful pursuits. The spectacular and rapid strides made in the manufacture of steel during the last hundred years were hastened by the invention during the decade 1860 to 1870 of two great steelmaking processes-the Bessemer and the open-hearth process.

Jan 1, 1936

By T. Cantwell, N. C. Rasmussen, H. E. Hawkes

Beryl is a mineral that may be difficult to distinguish from quartz by casual field inspection. The easily recognized green color and hexagonal crystal form of coarse-grained beryl are by no means universal, even in beryl from pegmatitic deposits. If it occurred as a fine-grained accessory mineral in an igneous rock, it would almost certainly escape detection unless samples were submitted for petrographic or chemical analysis. There may be substantial deposits of some beryllium mineral, other than beryl, that has been overlooked because that mineral also closely resembles the common rock-forming minerals. A reliable and simple method of identifying beryllium minerals and determining the beryllium content of a rock would be helpful in exploration. This article describes preliminary experiments in applying nuclear reaction to the qualitative identification of beryl and to the semiquantitative determination of the beryllium content of rock samples. Gaudin,1,2 the first to apply a nuclear reaction in detecting beryllium minerals, developed a method that irradiates the sample with gamma rays, which react with beryllium nuclei to produce neutrons. The neutrons are then measured with standard equipment. The cross section for this reaction is about 1 millibarn. The cross section is a measure of the probability that a reaction will take place, for example, between a beryllium nucleus and an incident gamma ray or alpha particles.3-5 At 1-millibarn cross section for the reaction, satisfactory performance required a source strength of the order of 1 curie (3.7 x 10"' disintegrations per sec, where each disintegration releases one or more gamma rays). The reactions will not take place if the gamma radiation is below a minimum energy, in this case 1.63 mev. The size of the source and the energy of the radiation made heavy shielding necessary for these experiments, both to reduce the background count of the neutron counter and to safeguard personnel. The original discovery of the neutron by Chad-wick in 1932 resulted from experiments with another nuclear reaction, induced by bombarding beryllium with alpha particles in which the products are carbon-12 and neutrons. The equation for this reaction is as follows:' " ,Be" + ,He'? 6C12 + 8,n' [1] re-particle neutron In the above nuclear equation (Eq. 1), the sub- script number indicates the number of protons in the nucleus (the atomic number) and the superscript the total number of neutrons and protons (approximately the atomic mass). For the alpha-neutron reaction the cross section is about 250 milli-barns, or 250 times that of the gamma-neutron reaction used by Gaudin. The positively charged alpha particle is repelled by the positive charge of the beryllium nucleus; it must, therefore, have a certain minimum energy in order to approach close enough to the beryllium nucleus to react. For reaction with the beryllium nucleus, the lower limit of the alpha-particle energy is 3.7 mev. The alpha-neutron reaction, with polonium-210 as an alpha source, was selected for the present experiments. Alpha particles are emitted by polonium-210 at 5.30 mev, which is adequate for the reaction with beryllium. Furthermore, this isotope of polonium emits alpha particles with negligible associated gamma radiation, thus eliminating the necessity of shielding. The half-life of polonium-210 is 138 days. Inasmuch as alpha particles carry a possible charge and are large compared with most nuclear particles, their energy is rapidly dissipated in passing through matter. Their range in standard air is 3.66 cm,3 and they penetrate only a few tens of microns into a mineral sample. The short range in air can be minimized by preparation of a flat sample surface that can be brought very close to the alpha source during analysis. On the other hand, short range of alpha particles in air lessens the radiological health hazard and makes it possible to use this method without shielding. It must be emphasized, however, that the alpha emitters are potentially very dangerous if they enter the human body. Polonium must be handled with extreme caution. The literature has reported experiments on the yield of neutrons from reaction of alpha particles with beryllium nuclei. Feld" reports that in intimate mixtures of polonium and beryllium, 3 x 106 eutrons per sec are produced per curie of polonium. Elsewhere in the same reference it is stated that a sandwich-type source yields about one third as many neutrons as an intimate mixture. A table of neutron yields for full energy polonium alpha-particles on thick targets as reported by Anderson7 is the basis of Table I. From Table I it can be deduced that the elements most likely to interfere, i.e., those that also produce neutrons when bombarded by alpha particles, are boron and fluorine. These data also show that it will probably not be possible to determine very small quantities of beryllium in rocks because of the masking effects of the major elements, sodium, magnesium, and aluminum. The neutrons emitted in the alpha reaction are detected by another nuclear reaction. Either of the

Jan 1, 1960

New York Meets first Wednesday after first Tuesday of each month. DAVID H. BROWNE, Chairman, JOHN H. JANEWAY, Vice-Chairman. F. E. PIERCE, Secretary, 35 Nassau St., New York, N. Y. P. A, MOSMAN, Treasurer. Boston Meets first Monday of each winter month. HENRY L. SMYTH, Chairman. ALFRED C. LANE, Vice-Chairman. HENRY A. WENTWORTH, Secretary-Treasurer, 60 India St., Boston, Mass. ROBERT H. RICHARDS,- ALBERT SAUVEUR. Columbia Holds four sessions during year. Annual meeting in September or October. FRANK A. ROSS, Chairman. RUSH J. WHITE, Vice-Chairman. LYNDON K. ARMSTRONG, Secretary-Treasurer, P. O. Drawer 2154, Spokane, Wash. FREDERIC KEFFER, FRANCIS A. THOMSON.

Jan 7, 1915

(There are 70 Student Chapters in the United States, 2 in Canada) University of Alabama-University, Alabama, Mining and Metallurgical Society, Win L Mason University of Alaska-College, Alaska, Mining Society of the University of Alaska, E H Beistline University of Arizona-Tucson, Arizona, Miners Society Birmingham-Southern College-Birmingham, Alabama, Pick and Hammer Club, Daniel D Arden University of British Columbia-Vancouver, British Columbia, G M Dawson Club, H C Gunning University of California-Berkeley, California, Mineral Technology Association, W H Somerton Carnegie Institute of Teehnology-Pittsburgh, Pennsylvania, The Metals Club, Gerhard Derge Case Institute of -Technology-Cleveland, Ohio, Case Metallurgical Engineering Society, Robert F Hehemann

Jan 1, 1956

By Francis S. Kendorski

INTRODUCTION Nuclear waste has been generated since the time of the Curie's and continues to be generated worldwide at an ever-increasing rate as the world will (and should) rely more and more upon fission (and hopefully fusion) for power. Also, the needs for strategic weapons will also generate so-called defense wastes. The largest class of high level nuclear waste (HLW) is spent fuel, the tail end of the nuclear reactor fuel cycle. At present, spent fuel is stored at the reactors producing it or at a few accepting places for away-from-reactor storage. All such storage facilities, as presently constructed, will begin to run out of usable storage space during the next decade or so. Congress enacted and President Reagan signed into law in early 1983 the National Nuclear Waste Policy Act of 1982. This law provides for the permanent isolation of nuclear waste in deep geologic repositories. The Act sets 1998 as the date at which the first repository should be operational. This date is extremely ambitious, and the Department of Energy (DOE), which is charged with the responsibility of constructing and operating repositories, admits that this date will slip by at least a few years. The Act also provides for licensing of repositories by the Nuclear Regulatory Commission (NRC) in a fashion very similar to nuclear power generating reactors. This requirement imposes a very special rigor on the analyses, investigations, designs, construction, and operation of repositories so as to assure the protection of the public and the environment from radioactive contamination. In addition the states and affected Indian Tribes must be consulted, especially concerning siting, and, needless to say, no one wants a HLW repository in their back yard.

Jan 1, 1984

By Hans W. Brodbeck

The main problem in tunneling without the use of explosives lies in the development of tools capable of continuous mechanical destruction of rock, resulting in a fragmentation which lends itself to a smooth, uninterrupted transportation of the broken rock away from the tunnel face. While all moles of U.S. design mainly achieve this by crushing the rock by means of "disk cutters" or "roller bits," a boring system based on the principle of cutting the rock came into being in Europe, whereby the rock is worked in a manner very similar to the milling of metals. For tunneling purposes, this principle was first developed by the late Austrian engineer Wohlmeyer. Between late 1962 and the spring of 1965, the first experimental machine was tested in a German coal mine, working in coal and shale over a distance of some 3000 ft, divided over two runs separated by a period of time to allow for equipment modifications. In 1964, a collaboration was started between Wohlmeyer and the Habegger engineering firm of Thun in Switzerland. The normal Habegger range of equipment consists of aerial ropeways, ski lifts, and certain tool machines, to which in later years have been added monorail passenger-transport systems. One of these was installed as the main mode of transport at the 1967 World Fair in Montreal. After taking over the Wohlmeyer patents, Habegger further developed the original cutting principle, aiming at more robust machines in order to be able to tackle harder rock. A first machine was built and tested at a site near Thun in sandstone averaging 17,000 psi compressive strength and limestone of 25,000 psi. In May 1966 this machine was delivered to Japan for the boring of a pilot tunnel for the Honshu-Hokkaido railway connection under the sea. A second machine, incorporating many improvements based on experience gained with this first mole, was built during 1966 and tested in the same limestone as mentioned previously (25,000 psi), before being installed to bore the head race tunnel of the Julia hydroelectric power scheme near St. Moritz, Switzerland, in the early summer of 1967 (Fig. 1 ) .

Jan 1, 1970

The Atlanta Mine is located in east central Nevada, in Lincoln County, 116 km (72 miles) south of Ely and 80 km (50 miles) northeast of the old mining town of Pioche. From this famous district, high-grade copper ore was mined and shipped to a smelter in Wales in the 1850s; an early day lead blast furnace was also in operation. The Standard Slag Company began operations in May 1975 on the well known Atlanta Mine, which was operated by Roy Hardy in the 1930s. The mill is currently processing 450 mtpd (500 stpd) of gold-silver bearing ore. Mining by open pit is in a brecciated zone occurring between limestone-dolomites on the foot wall and tertiary rhyolites on the hanging wall. The quartz breccia is considered among the most abrasive in the world - shovel teeth must be replaced every week. Stripping ratio is 3.9 to 1.0. Because of the hard abrasive ore, the crushing plant consists of four units: two jaw crushers in series, one Hydrocone, and one Gyradisc. Mine feed to the primary crusher is limited to 610 mm (24 in.) in size. The remaining crushers work in closed circuit with screens to produce a mill feed of 6 to 13 mm (0.25 and 0.50 in.). Hardness of the ore is demonstrated by the fact that the reversible liners of the primary jaw crusher had to be replaced in early 1978 after handling only 39,000 mt (44,000 st) at a cost of $0.095 per mt ($0.086 per st). Another example of the extreme abrasiveness of the breccia ore was the total cost per ton in 1977 for all wear parts in the comminution circuit, including screens and grinding media. This amounted to $2.84 per mt ($2.58 per st). The Atlanta grinding plant consists of three ball mills to grind the 7 mm (1 /4 in.) crushing plant product to 85 to 90% minus 150 microns (100 mesh). Feed rate to the primary Tricone mill is determined by maintaining a cyclone overflow at 28 to 38% solids, which controls the grind mentioned above. A mixture of 90 and 65 mm (3.5 and 2.5 in. ) balls are charged to this primary mill. Both the secondary mills are charged with 50 mm (2 in ) balls. Total ball consumption is 2 kg per mt (4 lb per st). All three ball mills use rubber liners. Primary mill cyclone underflows are fed to the secondary mills close circuited with the same cyclones.

Jan 1, 1981

COMMITTEES Committee on Arrangements DAVID H. BROWNE, Chairman LAWRENCE ADDICKS THOMAS T. READ P. E. BARBOUR BURR A. ROBINSON GEORGE D. BARRON F. T. RUBIDGE KARL EILERS E. MALTBY SHIPP LOUIS D. HUNTOON BRADLEY STOUGHTON H.A. MEGRAW EDWARD B. STURGIS ARTHUR L. WALKER

Jan 4, 1917

By J. V. Gluck, Ping-Wang Chiang

The tellurium-rich region of the Sb-TI-Te ternary system was investigated by means of DTA, metallo-graphic, X-ray, and electron beam microprobe techniques on the sections Sb2Te3-T12Te3, SbTlTe2-Te, SbT1Te2-Sb2Te3, and SbTlTe2-T12Te3. The phase behavior of this region is summarized in terms of four ternary invariant reactions and a schematic reaction diagram is suggested. Isopleths for the sections SbT1Te2-Sb2Te3, Sb2Te,-T12Te3, and SbTlTe2-Te were constructed, and a schematic diagram of the projections of the liquidus lines and invariant planes is presented. No evidence was found to support the existence of the ternary compound "SbTlTe3", or pseudo-binary behavior of the section T12Te3-Sb2Te3, as reported by Borisova and Efremova. Electrical conductivity, Seebeck coefficient, and thermal conductivity measurements were made at room temperature on fully annealed samples. 1 HE phase relationships in chalcogenides are often complex and difficult to resolve, particularly since the approach to equilibrium is a rather slow process. For example, the phase diagram of the T1-Te binary system was in doubt until clarified by Rabenau et al.,1 the phase fields at compositions near Bi2Te3 in the Bi-Te binary system have only recently been satisfactorily elucidated by Glatz,2 and there may still be some question as to the extent of the Sb2Te3 field in the Sb-Te system.3-5 In ternary systems, the existence of the compound "AgFeTe2" was the subject of a number of conflicting reports6-8 and the stoichiometry of the composition "AgSbTe2" was in doubt for a period of time.9 Recently, questions have arisen regarding the existence of certain compounds in the ternary systems Bi-Tl-Te10-14 and Sb-Tl-Te.15 The impetus for studies of these latter systems stemmed from the report of Borisova et a1.10 of a congruently melting ternary compound, "BiTlTe3", which apparently had extremely favorable thermoelectric properties for room-temperature cooling applications. Attempts by other investigators to produce the compound or confirm the transport properties proved to be unsuccessful.12-14 Recently, Chiang and Gluck14 reported studies of the phase relations in the tellurium-rich region of the Bi-T1-Te system which indicated that the section T12Te3-Bi2Te3 was not pseudobinary as suggested by Borisova et a1.10 The contention of Spitzer and sykes12 was supported that the composition "BiT1Te3" was multiphase, with the primary constituent actually being BiTlTe2, a compound whose existence has been well demonstrated.16,17 The investigation reported in the present paper was prompted by a later report of Borisova and Efremova15 on a similar study of the section T12Te3-Sb2Te3 from the Sb-T1-Te system. They also claimed this section to be pseudobinary, and that a ternary compound "SbTlTe," was formed peritectically. Some "preliminary" crystallographic data were given for the compound and thermoelectric transport properties were presented. In view of the questions concerning the behavior of the Bi-T1-Te system and the existence of the compound "BiT1Te3" it was suspected that the Sb-T1-Te system might behave in a similar fashion, particularly in light of the known existence of a compound SbT1Te2, iso-structural with BiT1Te2.17 Consequently, an investigation was undertaken to clarify the phase relationships in the tellurium-rich region of the Sb-T1-Te system. It is the purpose of this paper to present the results of this study, including a representation of the phase relations, isopleths for various composition sections, and the determination of some phase compositions and transport properties. EXPERIMENTAL PROCEDURES Commercially available high-purity (99.999+ pct) elements, purchased from the American Smelting and Refining Co., were used for the sample preparation. All samples were made from thoroughly mixed powders of previously prepared master alloys: SbTlTe2, Te, Sb2Te3, and T12Te3. Stoichiometric quantities of the constituents for each 10-g sample were weighed into a specially cleaned fused silica tube and sealed under a vacuum of better than 5 x 10-5 torr. The sealed constituents were fused and reacted at 650° to 750°C for at least 4 hr under continuous agitation in a "rocking" furnace, and the resulting product was air-cooled. The tube was opened and the sample was ground to a powder. A portion of the powder was rebottled in a DTA tube under vacuum, and the rest of the material was similarly resealed in a separate tube, re-fused in the rocking furnace, and again cooled to make the ingots for electrical and microstructural studies. All samples were subjected to further heat treatments as discussed in the section on experimental results. Each DTA tube was made of 7-mm-OD fused silica tubing with a concentric 2-mm-ID depression about 4 mm long formed in the bottom to accommodate a thermocouple. The size of a DTA sample was 0.5 to 1.0 g. An Aminco Thermoanalyzer whose accuracy was within 2°C18 was used for the DTA measurements. The metallographic samples were prepared by conventional techniques. A solution of FeCL dissolved in a methanol-HC1 mixture was found to be the most satisfactory etchant. Electron beam microprobe scanning and point-count examinations were made on polished and unetched samples using an ARL Electron Microprobe at an electron beam voltage of 20 kv. The detectors were set to receive characteristic La1 radiation. Calibration standards of the pure elements were incorporated in each sample mount; quantitative point counts were calibrated by a method similar to Ziebold

Jan 1, 1969

By E. D. Gardner

When the National Forests were created, all lands embraced in their boundaries were exempted from all forms of entry, except mineral claims. Later, by Act of June 11, 1906, and as amended by Act of Aug. 10, 1912, provision was made allowing homesteads on areas chiefly valuable for agriculture and not necessary for the public use. Patents to mining claims in the Forests are granted the same as on land not in the Forests, irrespective of timber or other values. It is the policy to encourage the highest use of the Forests. As a business proposition, it is a good policy to have mines developed in the Forests. Their development in remote or inaccessible regions causes the country to be opened up and, in addition to the local market which the mines create, means of transportation are afforded to outside markets. No examination of mining claims is made until patent has been applied for, unless they are actively interfering with the administration of the Forest. In this case, an examination is made, and if there is evidence that the claims are being held in good faith they are in no way interfered with. Timber is never sold from a mining claim except with the consent of the claimant, or unless it is clearly shown, after an examination, that the claim is abandoned. In the case of fire-killed timber, which rapidly deteriorates by standing, a contract bond arrangement can be made for the sale of the timber which protects the interests of both the mining claimant and the government. The promiscuous locating of mining claims has in the past caused considerable trouble. It has been, and still is, the custom in some parts of the West to locate a mining claim when the surface rights of any particular area are desired, irrespective of the mineral character of the ground. This has been done to hold power sites, town sites, summer residences, springs, etc. When the ground is desired for any of these purposes, what is known as a Special Use Permit will be issued at a nominal sum, to legalize the occupancy. In most instances, it is far cheaper to take out one of these permits than to do the annual assessment work on a mining claim, but, of course, patent to the ground cannot be obtained in this manner. If mineral were discovered on the land covered by a Special Use Permit, it would ordinarily be the policy to cancel the permit if it were clearly

Jan 1, 1915

By Louis A. Panek

Ground movements in the zone adjoining an active cave were measured at four sites in the San Manuel Mine. Measurements were made to detect extension and inclination, basic components of displacement, which can readily be duplicated by mine personnel using relatively simple equipment. The displacements demonstrated the development of a zone of strain relief surrounding the active cave, within which the ground tends to migrate toward the cave, and extension cracks develop tangential to the cave. This expansion of the ground surrounding an active cave can be exploited to promote future caving; it also creates special problems with respect to the design of an effective ground support system for mine openings in the production area.

Jan 1, 1981

New York Meets first Wednesday after first Tuesday of each month. DAVID' H. BROWNE, Chairman. JOHN H. JANE WAY, Vice-Chairman. F. E. PIERCE, Secretary, 35 Nassau St., New York, N. Y. P. A. MOSMAN, Treasurer. LEWIS W. FRANCIS. BENJAMIN B. LAWRENCE. Boston Meets first Monday of each winter month. HENRY L. SMYTH, Chairman. ALFRED C. LANE, Vice-Chairman. HENRY A. WENTWORTH, Secretary-Treasurer, 60 India St., Boston, Mass. A. H. EUSTIS, F. G. STANTIAL. Columbia Holds four sessions during year. Annual meeting in September or October. STANLY A. EASTON. Chairman. FREDERIC KEFFER, Vice-Chairman. LYNDON K. ARMSTRONG, Secretary-Treasurer, P. O. Drawer 2154, Spokane, Wash.

Jan 3, 1916

New York Meets first Wednesday after first Tuesday of each month: DAVID H. BROWNE, Chairman. JOHN H. JANEWAY, Vice-Chairman. F. E. PIERCE, Secretary, 35 Nassau St., New York, N. Y. P. A. MOSMAN, Treasurer. LEWIS W. FRANCIS. BENJAMIN B. LAWRENCE. Boston Meets first Monday of each winter month. HENRY L. SMYTH, Chairman. ALFRED C. LANE, Vice-Chairman. HENRY A. WENTWORTH, Secretary-Treasurer, 60 India St., Boston. Mass. A. H. EUSTIS, F. G. STANTIAL. Columbia Holds four sessions during year. Annual meeting in September or October. FRANK A. ROSS, Chairman. RUSH J. WHITE, Vice-Chairman. LYNDON K. ARMSTRONG, Secretary-Treasurer, P. O. Drawer 2154, Spokane, Wash. FREDERIC KEFFER, FRANCIS A. THOMSON.

Jan 1, 1916

By L. Burris, C. H. Stockman, I. G. Dillion

Zone melting is a purification process in which separation of impurities is effected by slowly moving a narrow melted zone through a bar of solid material. Equations are presented which 1—predict the concentration profiles after successive passes of the zone and 2—give the limiting distribution of solute along the bar after an infinite number of passes of the molten zone. These equations take into account the effect of normal freezing in the last zone length. These equations were solved numerically using an electronic computer, and the concentration profiles are presented as a function of the solute distribution coefficient and the ratio of molten zone to total bar length. ZONE MELTING is a purification process in which separation of impurities is effected by slowly moving a narrow melted zone through a bar of solid material. Separation occurs if the solid freezing from a solution at any moment has a composition different from that of the liquid from which it is freezing. Solutes which lower the freezing point will tend to remain in solution and will be moved in the direction of zone travel. Solutes which raise the freezing point will preferentially freeze out, and they will be moved in a direction opposite to that of zone travel. After repeated unidirectional passage of a molten zone through a bar of material, impurities will be concentrated in the ends of the bar. A limiting concentration gradient will be reached in the bar after a large number of passes of the molten zone. Both the magnitude of this limiting concentration gradient and the rate of movement of solute in any pass depend on the zone length and on the equilibrium concentrations of solute in the liquid and solid phases. The basic theory of zone melting was thoroughly covered by Pfann.1 The purpose of this paper is to extend the theory of zone melting by presenting 1—equations which relate the concentration profiles in successive passes of the zone and 2—equations which give the limiting distribution of solute along the bar after an infinite number of passes of the molten zone. These equations take into account the effect of normal freezing* in the last zone length concentration of a given solute in the solid to the concentration of the same solute in the liquid. Analytical methods for determining the concentration profiles after any pass have been developed by Lord2 and Reiss. The method developed by Lord does not take into account normal freezing in the last zone and also becomes very complicated when the number of passes becomes large. The method developed by Reiss enables the direct calculation of the complete concentration profiles (including that in the last zone) after any pass for values of k close to unity (0.9 < k < 1.1). Both methods are useful and provide valuable insight into the zone melting process. The equations given in this article are based on the same assumptions used by Pfann. These are: 1—uniform composition in the liquid, 2—negligible diffusion in the solid, 3—constant distribution coefficient, 4—constant length of the liquid zone (except at the ends), and 5—solubility of the solute in the melt is not exceeded at any point. Equations for Concentrations in Successive Passes For a melted zone of length 1 at the left-hand end of a bar of uniform unit cross-section, the amount of solute in the liquid is J0Cn-1(x) dx [1] where the subscript is the number of the pass. Cn-1(x) represents the concentration (expressed as weight per unit volume) obtained in the previous

Jan 1, 1956