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By Westwater, J. S.

The Mather mine of The Negaunee Mine Co. embraces nearly all of Sections 1 and 2, T47N, R27W. within the limits of the cities of Negaunee and Ishpeming on the Marquette iron range of Michigan's Upper Peninsula. Operations of the Negaunee Mine Co., the stock of which is jointly owned by Bethlehem Steel Co. and The Cleveland-Cliffs Iron Co., are under the direction of the latter company. The opening of the Mather mine was described by C. W. A1len. Mather "A" shaft was completed to an initial depth of 2352 ft in early 1943. The shaft capacity of over one million tons yearly is in prospect of being realized by orderly development and mining, and sinking of the second or "B" shaft then started in accordance with previous planning. Mather " B, " also a vertical shaft, was designed as a twin to Mather "A" shaft and the sinking technique developed at Mather "A" was utilized in "B" shaft operation.

Jan 1, 1949

LIST OF THE MEETINGS OF THE INSTITUTE AND THEIR LOCALITIES FROM ITS ORGANIZATION Transactions Number Place Date Vol Page I Wilkes-Barre, Pa * May, 1871 I 3 II Bethlehem, Pa August, 1871 I 10 III Troy, N Y November, 1871 I 13 IV Philadelphia, Pa February, 1872 I 17 V New York, N Y * May, 1872 I 20 VI Pittsburg, Pa October, 1872 I 25 VII Boston, Mass February, 1873 I 28 VIII Philadelphia, Pa * May, 1873 II 3 IX Easton, Pa October, 1873 II 7 X New York, N Y February, 1874 II 11 XI St Louis, Mo * May, 1874 III 3 XII Hazleton, Pa October, 1874 III 8 XIII New Haven, Conn February, 1875 III 15 XIV Dover, N J * May, 1875 IV 3 XV Cleveland, 0 October, 1875 IV 9 XVI Washington, D C February, 1876 IV 8 XVII Philadelphia, Pat June, 1876, V XVIII Philadelphia, Pa October, 1876 V 9 XIX New York, N Y February, 1877 v 27 XX Wilkes-Barre, Pa * May, 1877 vi 3 XXI Amenia, N Y October, 1877 vi 10

Jan 1, 1910

By B. C. Burgess

AFTER many years of close and friendly association with talc and soap-stone, this orthographically distinguished mineral steps forth in this edition, for the first time in a chapter of its own. Pyr, the Greek for fire, and phyllite, a rock or stone, form its name and at the same time refer to the first recorded use of pyrophyllite as firestones or hearthstones. Another derivation of "phyllite" is from the Greek phyllites, "of leaves," alluding to the beautiful white radial crystal aggregates that form when pyrophyllite is heated. Pyrophyllite used by the Chinese for carving is called agalmatolite, from the Greek agolma, meaning an image. COMPOSITION AND PROPERTIES Pyrophyllite has previously been grouped with talc because of the close similarity of the minerals in physical and optical properties. They have the same space group; and chemically they are closely related, pyrophyllite being the aluminum silicate A12Si4010(OH)2 and talc the magnesium silicate Mg3Si4010 (OH) 2. Another arrangement of the pyrophyllite formula is generally given as A12034Si02H20 because it expresses the chemical composition as usually determined (alumina 28.3 pct, silica 66.7 pct, water 5.0 pct). Vanderbilt gives pH values of pyrophyllite 5.6 to 8.4.29 Pyrophyllite usually is white, pale green, cream or pale yellow, buff or light gray. It is found in darker shades and other colors principally due to oxidation of contained iron minerals. It is translucent in thin sections. In hardness it is 1 to 2 in the Mohs scale. Its specific gravity is 2.8 to 2.9. In bulk specific gravity, the powdered mineral ranges from 0.4 to 0.7. Its luster is pearly to dull; it is infusible in the Bunsen burner flame, slightly affected by aqueous solutions of sodium carbonate and hydrochloric acid. It is decomposed by sulphuric acid, with separation of gelatinous silica. It is characterized chiefly by its micaceous structure and cleavage, its softness and greasy feel. Two other varieties occur

Jan 1, 1949

Executive ROBERT E. TALLY, Chairman WILLIAM H BASSETT JOHN A. MATHEWS Louis S. CATER EDGAR RICHARD Finance HENRY KRUMB, Chairman H A GUESS H G. MOULTON Admissions ERLE V. DAVELER, Chairman GEORGE D BARRON H K MASTERS JOHN M. LOVEJOY P. A.-MOSMAN Alternates E. L. ESTABROOK C. E MEISSNER J. A. SINGMASTER FRED H. KAY

Jan 1, 1923

By R. W. Fenn, H. A. Lepper, W. R. Hibbard

THIS paper reports the results of static tension and torsion tests made on single crystals of alpha brass for the purpose of determining its elastic coefficients. 70-30 alpha brass was chosen because it has been used extensively in the study of the plastic deformation and because it has the following desirable characteristics: (1) face-centered cubic structure, (2) marked elastic anistropy, (3) low elastic modulus. In 1928 Masima and Sachs' using static methods reported the following values for the elastic coefficients of 72-28 pct alpha brass: S11 = 19.4 X 10-13' cm2 per dyne S12 = —8.35 X 10"' cm2 per dyne S44 = 13.9 X 10-13= cm2 per dyne These values were obtained from the measurements shown in fig. 1. The experimental points for both tension and torsion lie consistently below the lines drawn to represent them. Fig. 2 shows the stress-strain curves for their specimens. Only a few points in the elastic range of these curves were available to obtain their values for Young's modulus. Therefore, it was considered that a re-evaluation of these data was desirable. In addition a variation of from 1.13 to 1.485 kg per mm2 was found in the values of the critical resolved shear stress for 70-30 alpha brass reported by Burghoff,² Treuting and Brick: Martin,4 Maddin, Mathewson and Hibbard5,6 and von Goler and Sachs.' Therefore, it was desired to evaluate the conclusion of Boas and Schmid8 that a constant resolved shear stress and not a constant elastic shear initiates plastic deformation. Theoretical Considerations*: The elastic deformation of cubic crystals may be defined by three elastic coefficients (S11, S12, S44,) or three elastic parameters (C,,, C,, C,,). These coefficients or parameters are sufficient to define the stress and strain relations for cubic crystals in the generalized form of Hooke's law referred to Cartesian coordinates. Elastic parameters and coefficients in the cubic system are related by the expressions: C11 —S11+S12/(S11-S12)(S11+2 S12) C12=-S12/(S11-S12)(S11+ 2 S12) (S11 — S12) (S11 + 2 S12) [2] C44 =1/S44 PI It is possible to determine all the elastic coefficients for a cubic metal by measuring two of the three elastic constants: Young's modulus (E), torsion modulus (G), or compressibility (S). The following relations exist between crystallographic orientation and E, G and S for cylindrical crystals of the cubic system: 1/E = S11 — 2 [(S11 - S12) — Su] (?1² ?2² + ?2²?83 + ?3² ?1²) [4]

Jan 1, 1951

By Morris M. Fine, Norwood B. Melcher

It is out of the question, at this time, to select any one prereduction process as superior to the others. It is apparent that several share a basic similarity and that within the groups listed in Part 1, the reduction vessel is sometimes the only significant variable. Claims as to the virtues of one machine over another are difficult to substantiate: one may be rapid, another thermally frugal. Based on published data, however, all seem to be performing adequately. It would appear that processes based on carbonized pellets are most applicable to foundry iron at low production rates. Adaptation to large scale manufacture of blast furnace hot metal or to agglomeration of fine concentrates at the mine site is much less likely.

Jan 8, 1966

The Climax Molybdenum Company' s newest operation is the Henderson project, which is located on the east side of the Continental Divide. Ore reserves are estimated at more than 300 million tons at a grade of 0.49% MoS2. For mining the ore a modified panel caving system is used. The ore is transported to the Henderson mill on the west side of the Continental Divide on a 42 in. (1.07 m) gauge railroad through 9.6 miles (15.4 km) of tunnel and 4. 8 miles (7.7 km) of surface track, a total distance of 14.4 miles (23. 2 km). Each train consists of 30 ore cars with capacity of 22 st (20 mt) of ore or 660 st (599 mt) per train. The unmanned trains operate completely automatically. At the 54 in. by 84 in. primary gyratory crusher, the bottom dump ore cars pass over a dump scroll to discharge at a maximum rate of 100 st (91 mt) per minute. Dumped ore falls onto a rock box before passing over a 17 ft long by 46 ft wide (5. 2 m by 14 m) grizzly set at a 40° angle with bar spacings of 7 ½ and 8 ½ in. (191 mm and 216 mm) openings. An estimated 30 to 50% of the ore (which at times is wet and sticky) passes through the grizzly. The operators report that a shallower angle on the grizzly, perhaps 35º to 37º, would have been sufficient and would have prevented impact on the back of the crusher pocket by large boulders. This pocket as well as the crushed ore pocket under the crusher is lined with AR plate. The accompanying drawings show a "future splitter" and the operators are planning the installation of this unit to prevent impact and subsequent damage to the crusher spider. Crushed ore at an 8 to 9 in. (203 mm to 229 mm) size joins the grizzly undersize in the pocket beneath the crusher. This pocket is sized at 660 live st (599 mt) so that it will accept an entire trainload of ore. Crushed ore is removed from the pocket by a four-speed, 84 in. (2. 1 m) apron feeder operating at 9.6 to 29. 3 fpm (2.9 to 8.9 mpm). A 60 in. (1.5 m) takeaway conveyor operating at 480 fpm (146 mpm) delivers the crushed ore to a 58,000 st live and 193,000 st total (52,600 and 175, 100 mt) open stockpile under an A -frame supported tripper gallery. Impact idlers on the takeaway conveyor under the apron feeder discharge are mounted on wood blocks for a cushioning effect and ripped belt detecting bars are located behind each impact idler. The conveyor tunnel is of corrugated and galvanized steel construction rather than concrete. The concrete crusher enclosure is circular in design from its lowest level at elevation minus 110 ft 4 in. (minus 33. 6 m) to elevation

Jan 1, 1978

By R. C. de Lange

An improved replica technique is developed for a nondestructive study of the nucleation and growth of fatigue cracks. Three different growth stages of a fatigue crack were observed. An initial stage of high growth rate is followed by a long period of very slow growth, until finally a third period of high growth rate leads to fracture. THE metal-fatigue process is of a very complex nature. The experimental approach towards fatigue is susceptible to many minor influences which, together with the unavoidable scatter in testing results, makes the interpretation a matter of extreme care. The generally accepted fact that, in a homogeneous material, the fatigue cracks start at a free surface indicates that surface studies may contri-but in an essential way to a better understanding of the fatigue mechanisms. Indeed metallographic observations of the fatigue phenomena have been very fruitful in the last decade. The study of extrusions, intrusions, and persistent slip bands has contributed much to the present knowledge of the early processes in fatigue.' The drawback of the current metallographic techniques lies in the fact, however, that either observations of fatigue phenomena had to be made in a destructive way after an only partly executed test or a sequence of observations on the same test bar was only possible on notched specimens.2 4 In both cases an uncertainty exists as to the nucleation and growth of the fatigue crack in an unnotched test bar, where the crack can start at any place of a large area and develops in a test bar, which is macroscopically

Jan 1, 1964

By M. G. Corson

THE iron-silicon alloy series has always been one of the most puzzling among the binary alloys. Examining the well known mechanical properties of the iron-rich alloys only we meet the following situation: The ultimate strength and yield point of alloys worked and annealed under the usual conditions represent nearly a straight line function of the silicon content up to 4.5 per cent. silicon (Fig. 1). Starting at the ultimate strength of 35,000 lb. and at a yield-point of 16,000 lb. for pure electrolytic iron, one reaches a -maximum strength of 93,000 lb. and a maximum yield point of 74,000 lb. at 4.5 per cent. silicon. This corresponds to an increase in ultimate strength by 13,000 lb. per each per cent. of silicon added and nearly the same rate applies to the yield point. The data mentioned are taken from the investigation by T. D. Yensen,1 and while they do not exactly corroborate the results obtained by earlier investigators, they seem to be the most correct. Plastic properties of the alloys are controlled by a much more complicated relationship. Up to 2.5 per cent. Si, the elongation stays close to 50 per cent. (in 2 in.) and the area reduction amounts to 85 per cent., a situation that forms the usual feature of all alloys representing strictly solid solutions. The plasticity of the latter is always nearly equal to that of their base metal. Beyond 2.5 per cent. silicon, the situation becomes much more complicated Yensen observed an enormous drop in elongation and area reduction at about 2.65 per. cent. silicon, where the first hardly reaches 10 per cent. and the second is still lower; he found, however, a considerable recovery in plasticity at about 2.8 per cent. Si and up to. 4.5 per cent. Si it is represented by 20 per cent. for the elongation and 30 per cent. for area reduction.

Jan 1, 1928

By Marius R. Campbell

Does mine-sampling show the commercial value of a coal, and if so, how should it be done? This question is often asked, but seldom answered. During the past summer, while engaged in securing coal for the Government coal-testing plant at St. Louis, I had an excellent opportunity to obtain information on this subject, and the results seem to furnish an answer to the questions propounded above. Sampling for the Geological Survey Coal-Testing Plant. In organizing the work of the testing-plant, it was decided that coal in car-load lots only would be accepted for testing, also that this coal should be loaded under the immediate supervision of a representative of the plant, so as to be certain that the car-load sample would be representative. As an additional check on the work, two mine-samples were to be collected from each mine visited, and these samples, as well as the sam¬ple from the car when it was received at the testing-plant, were to be carefully analyzed at the chemical laboratory, which was established in connection with the plant and operated under the direction of Prof. N. W. Lord, of the Ohio State University, Columbus, Ohio. Mine-Sanmhling:-Mine-samples were collected with great care by me and my assistants, Messrs. J. Shober Burrows, John W. Groves and Frank W. De Wolf. The dominant idea in the regulations which were adopted for mine-sampling was that it should be done in such a manner that the sample would have the same composition as the commercial output of the mine. .

Sep 1, 1905

By E. N. Harshman

Uranium mining and milling are rather new industries in Wyoming and South Dakota, but, in the past 15 years, ore valued at more than $400,000,000 has been mined and milled in the region. The major uranium deposits are in structural and/ or erosional basins or on the flanks of uplifts. The principal host rocks are medium- to coarse-grained sandstones that were deposited in continental or brackish-water environments and were derived in large part from the granitic cores of the uplifts and the sedimentary rocks that flank the cores. The ages of the host rocks range from Cretaceous to Miocene, but more than 95 per cent of the known reserves in the region are in rocks of early Eocene age. The bulk of the ore in the region is unoxidized and lies below the water table; some oxidized ore has been mined in the Powder River Basin and Black Hills districts. The unoxidized ore comprises pyrite, uraninite and/ or coffinite, marcasite, hematite, jordisite(?), and selenium. Minerals in the oxidized ore include hydrous uranium carbonates, phosphates, and sulfates and hydrous uranium and/ or vanadium silicates. The deposits are in the form of ore rolls that contain from a few hundred to a few hundred thousand tons of ore, ranging in grade from 0.1 per cent to 1.0 per cent U3O8. The rolls are at the margins of large tabular bodies of sandstone that has been altered by the orebearing solutions. The deposits are believed to have resulted from the interaction of an alkaline; oxidizing, ore-bearing ground water and a reducing environment. Exploration guides include the spatial relations of ore to altered sandstone, favorable lithology in the host rock, the content of certain elements and/ or compounds in ground water, and the relation of deposits to major paleodrainages.

Jan 1, 1968

By Richard A. Hawkins

O the American coal man, Australian coal mining most appear to have little, if any, influence on American coal-mining practice and to bear little relation to it. Actually, the relationship has been close, for Australian operators have carefully studied American practice by reading American technical publications, by consulting American engineers, and by visits to Ameriean operations. They have leaned heavily on America for their supply of mechanization equipment and many American mining-machinery manufacturers are active in that country, supplying its needs and furnishing technical assistance. Australia's influence on American coal mining has been obscure and probably negligible. However, it seems reasonable to assume that this influence will increase. The wartime development of air transportation will inevitably bring these two countries into much more intimate contact than existed in recent years. American servicemen. many of them former miners and coal-mining technicians, have visited Australian operation, while stationed in that country, have talked with operators and men over there, and undoubt-

Jan 1, 1945

By John Hall

SOME months ago one of the authors was asked to write a paper on the heat treatment of steel castings that would be more comprehensive than other matter lie had published; this is an attempt to present in condensed form the results of experimental work and actual practice carried out for the most part in 1907, 1908; and 1909. It is not a laboratory research and the work done was carried out for the express purpose of putting in practice the processes discovered as fast as possible. Most of the tests are the result of commercial practice and not of bars annealed in our laboratory; most of the micrographs were made for our own records and not for publication. Certain of the micrographs, therefore, are not as clear as we may wish but they were good enough for our purpose at the time they were made. The tests and micrographs are selected from several thousands in our files. All of these micrographs are magnified 60 diameters. These experiments were conducted almost entirely on steel made in a 3-ton bottom-blown converter, and most of the steel illustrated analyzes about 0.05 in phosphorus and sulfur. Unfortunately, a certain number of specimens are shown of which we do not have the complete analysis, but in most cases in which the phosphorus and sulfur vary much from the figure just given that fact is noted. For purposes of comparison, we have included a certain number of micrographs and tests of steel made in the electric furnace, some of which were from specimens made in other shops and some in our own shop, and some tests of acid open-hearth and tropenas steel.

Jan 9, 1919

The following is an incomplete list of members and guests who called at Institute headquarters during the period Dec. 10, 1918 to Jan. 10, 1919. P. G. Bandy, Mexico City. Wm. B. McKinley, Yonkers, N. Y. Bennett R. Bates, Berkeley, Cal. Captain C. E. McQuigg, Conn. William T. Bates, Mascot, Tenn. Lt. H. G. Mathews, Cal. Lt. Don C. Billick, Alturas, Cal. Lt. M. S. Mazany, Mich. L. E. Booth, Watertown, Mass. Ralph A. Meyer, Hill City, S. D. J. T. Boyd, Denver, Colo. C. F. Moore, Boston, Mass. J. R. Buchanan, Pasadena, Cal. H. W. Nichols, Chicago, Ill. Ensign G. M. Burke. R. B. Olsen, Mays Landing, N. J. Captain E. H. Clausen. M. L. O'Neale, Gouverneur, N. Y. F. L. Cole, Manila; P. I. F. W. Osborn, New York, N. Y. Joules Cousin. Lt. Fred S. Porter, Alaska. A. Faison Dixon, Washington, D. C. G. M. Richards, Palmerton, Pa. James T. Dixon, London, England. T. C. Roberts, E. Orange, N. J. Everett Drennen, Elkins, W. Va. W. E. Ruder, Schenectady, N. Y. F. Eichelberger, Helena, Mont. Ensign W. A. RuKeyser, Boston. R. B. Eldredge, Colorado Springs, Colo. A. H. Sawyer, Boston, Mass W. F. Ferrier, Ottawa. Lt. D. F. Schindler, New York. Martin Fishback, Benson, Ariz. L. G. Sparks, Greenshurg, Kan. T. E. Fisher, Dover, N. J. W. H. Staver, New York N. Y. D. C. Gilbert, Ft. Wayne, Ind. Douglas B. Sterrett, St. Cyr, Canada. Lt. Lauriston B. Herr, Cuba. Warren D. Thompson. G. S. Holmquist, Washington, D. C. Enrique Touceda, Albany, N. Y. Lt. E. Ross Housholder, Ohio. Mathew van Siclen. Hugh C. Ingle, Santa Rosa, Cal. Flying Cadet Christian Vrang, Cal. Lt. M. W. Kishman, Ariz. L. G. Weeks, Bisbee, Ariz. Hugo E. Koch, Watertown, Mass. C. E. Wheelock, Mogollon, N. M. H. M. LaFollette, LaFollette, Tenn. Major A. E. White, Washington, D. C. Clinton R. Lewis, Dawson, Y. T. Lt. J. L. White, Humboldt, Ariz. The Secretary of the Institute has received with sincere appreciation a Christmas card extending the season's greetings from the officers' mess of the 3d Tunnelling Company, Canadian Engineers, B. E. F., France, and takes this means of reciprocating to these officers and men of the company the best wishes of the members of the Board of Directors. Charles E. Addams has removed from Ray, Ariz., to Phoenix, Ariz., where he is chairman and director of the Arizona State Council of Defense.

Jan 2, 1919

New York Meets first Wednesday after first Tuesday of each month. J. E. JOHNSON, JR., Chairman EDGAR RICKARD, Vice-Chairman D. M LIDDELL, Secretary, 7 Wall St., New. York, N. Y C. A. BOHN, Treasurer JOHN V. N. DORR _ LEWIS W FRANCIS Boston Meets first Monday of each winter month. R. L. AGASSIZ, Chairman - JAMES G. CARLETON, Vice-Chairman E. E. BUGBEE Secretary-Treasurer, Mass. Inst. of Technology, Cambridge, Mass. W. E. C. EUSTIS G. A. PACKARD Columbia Holds four sessions during year. Annual meeting in September or October. S. S. FOWLER, Chairman J. C. HAAS, Vice-Chairman LYNDON K. ARMSTRONG, Secretary-Treasurer. P. O. Drawer 2154, Spokane, Wash. W. H. LINNEY

Jan 2, 1918

New York Meets first Wednesday after first Tuesday of each month. J. E. JOHNSON, Jr., Chairman EDGAR RICKARD; Vice-Chairman D. M LIDDELL, Secretary, 7 Wall St., New York, N. Y. C. A. BORN, Treasurer JOHN V. N. DORR - LEWIS W. FRANCIS Boston Meets first Monday of each winter month. R. L. AGASSIZ, Chairman JAMES G. CARLETON, Vice-Chairman E. E. BUGBEE Secretary-Treasurer, -Mass. Inst. of Technology. Cambridge, Mass. W. E. C. EUSTIS G. A. PACKARD Columbia Holds four sessions during year. Annual meeting in September or October. W. H. LINNEY, Chairman OSCAR LACHMUND. Vice-Chairman LYNDON K. ARMSTRONG, Secretary-Treasurer, P. 0. Drawer 2154, Spokane, Wash. STANLY A. EASTON S. SHEDD

Jan 1, 1918

New York Meets first Wednesday after first Tuesday of each month. J. E. JOHNSON, JR., Chairman EDGAR RICKARD, Vice-Chairman D. M. LIDDELL, Secretary, 7 Wall St., New York, N. Y. JOHN V. N. DORR C. A. BOHN, Treasurer LEWIS W. FRANCIS Boston Meets first Monday of each winter month. R. L. AGASSIZ, Chairman JAMES G. CARLETON, Vice-Chairman E. E. BUGBEE Secretary-Treasurer, Mass. Inst. of Technology, Cambridge, Mass. W. E. C. EUSTIS G. A. PACKARD Columbia Holds four sessions during year. Annual meeting in September or October. W. H. LINNEY, Chairman OSCAR LACHMUND, Vice-Chairman LYNDON K. ARMSTRONG, Secretary-Treasurer, P. O. Drawer 2154, Spokane, Wash. STANLY A. EASTON S. SHEDD

Jan 9, 1917

New York Meets first Wednesday after first Tuesday of each month. J. E. JOHNSON, JR., Chairman EDGAR RICKARD, Vice-Chairman D. MI. LIDDELL, Secretary, 7 Wall St., New York, N. Y. C. A. BOHN, Treasurer JOHN V. N. DORR LEWIS W. FRANCIS Boston Meets first Monday of each winter month. R. L. AGASSIZ, Chairman JAMES G. CARLETON, Vice-Chairman E. E. BUGBEE Secretary-Treasurer, Mass. Inst. of Technology. Cambridge, Mass. W. E. C. EUSTIS G. A. PACKARD Columbia Holds four sessions during year. Annual meeting in September or October. W. H. LINNEY, Chairman OSCAR LACHMUND, Vice-Chairman LYNDON K. ARMSTRONG, Secretary-Treasurer, P. O. Drawer 2154, Spokane, Wash. STANLY A. EASTON S. SHEDD

Jan 8, 1917

By C. A. Stetefeldt

FoR the convenience of those who do not care to enter into the details of this long essay, I begin with a summary of the most important results it presents. The extraction of silver by the lixiviation-process from ores which have been subjected to a chloridizing-roasting, is based upon the fact that silver chloride is easily soluble in solutions of sodium or calcium hyposulphite, and that silver is precipitated from such solutions by an alkaline sulphide, with regeneration of the hyposulphite salts. In case the ore contains lead a large portion of the latter is and dissolved, lead sulphate being soluble in hyposulphite solutions. If, at the same time, copper is present, the sulphides precipitated from the solution, contain silver, copper, and lead, a combination of metals not desirable for subsequent treatment. Mr. E. H. Russell, of Park City, Utah, is the inventor and the patentee in the United States and several foreign countries of a new lixiviation-process, based upon the chemical facts discussed in this paper. Mr. Russell has discovered that lead can be completely separated from a sodium hyposulphite solution, as lead carbonate, by sodium carbonate or purified soda-ash, without precipitating any copper or silver. After decanting the solution from the lead carbonate, silver and copper are obtained from it in the usual way. This method of separating lead prohibits the use of calcium poly-sulphide as a precipitant for the sulphides, because any calcium entering the regenerated lixiviationsolution would also be precipitated as a carbonate with the lead by soda-ash. Hence, a sodium sulphide must be employed. A full investigation has demonstrated that this is by no means detrimental. Sodium sulphide and hyposulphite are more advantageously used in the lixiviation-process than the corresponding calcium-salts. Another defect in the lixiviation-process consisted in the necessity of a very perfect chlorination of the silver in the ore, because silver in

Jan 1, 1885

By A. M. Gaudin, C. S. Chang

IN general, fatty acids or their alkali salts do not cause clean quartz to float. However, the presence of multivalent ions, such as the alkaline-earth metal ions and heavy-metal ions, can activate quartz and thus make it respond to soap flotation. The mechanism of activation and soap flotation of quartz has been studied.1-4 The problem was attacked by making flotation tests rather than by careful adsorption measurements on suspensions of ground quartz in solutions containing the activator and the collector. Attempts have been made to determine the adsorption of barium ion and calcium ion on quartz. The results have only qualitative value as the analytical methods were not adequately precise. Artificial radioactivity and progress in radioactivity detection have introduced a new analytical tool, which can have a sensitivity several orders of magnitude greater than that of other methods.5-6 In the experimental work described in this paper the radioactive tracers, barium 140 and carbon 14, were employed. Lauric acid was synthesized, having a radioactive carbon atom and was used with Ba140 to study the adsorption of barium and laurate ions from aqueous solution on ground quartz. Flotation tests, using the vacuum flotation technique,4 were run in conjunction with the adsorption experiments. The object of this investigation was to understand better the reaction mechanism of barium activation and soap flotation of quartz. Methods and Materials Quartz Sample Preparation: Lumps of hand picked quartz, washed free of stains, were reduced in size to -20 mesh in laboratory crushers. The product was boiled in concentrated hydrochloric acid to remove the abraded iron. The cleaned product then was ground dry in a laboratory porcelain mill, using siliceous pebbles, to pass through a 200 mesh screen. The ground product was deslimed by sedimentation at 37 microns. This -200 mesh +400 mesh material was subjected again to boiling with concentrated hydrochloric acid, followed by washing with distilled water and further desliming. The cycle was repeated until no trace of iron could be detected in the wash liquor. During the final washing, the pH of the wash water was checked to insure the complete removal of the acid from the mineral. The quartz then' was rinsed with conductivity water. The resulting product was dried in a drying oven and stored in mason jars. The impurities (spectrographic) were as follows: Al, 0.01 to 0.001 pct; Li, Mg, Mn,, Na, each less than 0.001 pct; Fe and Cu not detected. The specific surface of the quartz sample was determined by the krypton gas adsorption method.7 The average of two measurements was 881 sq cm per g. The calculated specific surface for 37/74 micron quartz particles, using a surface factor of 1.96,8 is 900 sq cm per g. This is in good agreement with the measured value of 881 sq cm per g. Beta-Counting Method: The radioactive isotope of barium used in the experimental work was barium 140. It has a sufficiently long half-life, 12.8 days, emits high-energy beta particles (up to 1.0

Jan 1, 1952