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By A. S. Joy

Vacuum flotation tests carried out according to the method of Schuhmann and Prakash1 have shown that the acid limiting edge of the flotation area for a Brazilian hematite, in the presence of dodecylamine, is a straight line of slope approximately unity. The flotation tests and the structure, surface ionization, and electrokinetic properties of this hematite have been fully discussed elsewhere. 2 The numbers of adsorbed H+, and OH- ions and collector molecules have been determined in the range of critical conditions defining the acid limit of the flotation area. The total amine adsorption is shown in Fig. 1 as a set of contours superimposed on the straight part of the flotation area. These were determined by spectro-photometric estimation of the complex formed between residual amine and the anionic dye Orange II.3 The ionic strength of the solutions was kept constant and at a value in sufficient excess of the amine concentration to ensure that the diffuse part of the double layer was populated predominantly by indifferent ions. Adsorption of H+ and OH- in the absence of amine was found by potentiometric acid-base titration in the presence of hematite.4 The form of the adsorption-titration curves suggested that the hematite surface behaves in an amphoteric manner, and that positively charged sites arise through loss of a hydroxyl ion, and negatively charged sites by loss of a hydrogen ion. On this basis, curves 8 and 9, shown in Fig. 2, were calculated from the titration curves. These show the variation of the numbers of positive (s +) and negative (s—) sites with pH. To distinguish between ionic and other modes of adsorption, zeta-potential determinations have also been made using the streaming potential technique. The influence of amine on the zeta-potential of the mineral over a wide pH range is shown in Fig. 3. The change in charge ?s, due to adsorption of amine ions in the Stern layer, was calculated by applying the Gouy-Chapman theory, as modified by Stem, to the results shown in Fig. 3. The validity of this treatment has been shown by Ottewill and Jaycock.5 The three full lines, Nos. (1) through (3), included in Fig. 2 show the relationship between ?s and pH at three amine concentrations. The general conclusion from the zeta-potential curves is that adsorption of amine causes a reduction in the negative charge on the surface. Comparison of the values shown in curves (1) through (3) of Fig. 2 with the - curve shows that the magnitude of the reduction is comparable with that of s - at any given

Jan 1, 1964

By Luther B. Eames

J. V. N. DORR, New York, N. Y.-I have read Mr. Eames' excellent paper on this' subject with great interest, for besides being connected with the design and installation of the first modern countercurrent decantation plant, he was associated with me in the development of the thickener in the Black Hills some years earlier, and has now been operating the largest plant that has used this method of treatment. His, discussion, of the influence of different factors on the results obtained is quite thorough, but several features I think may not be apparent to the reader who has not studied the subject carefully. 1. Grade of Ore That Can Be Treated.-Mr. Eames has shown graphically that' the assay of all solutions increases directly as the grade of the ore treated. He has not emphasized, however, the fact that, as most operators prefer to keep the assay of pregnant solutions down below a certain figure in order to insure complete precipitation, an increase in ore value beyond a certain point means a proportional increase in solution precipitated and therefore not only an increase in the percentage of dissolved gold recovered, but an actual descrease in tailing loss. The importance of the influence of the percentage of moisture in the underflow on loss is made clear, and I. may add that unless it is quite evident that pulp can be safely settled to 50 per cent. solids, or more, it is usually advisable to use a continuous filter at the end of. a decantation plant to reduce losses in cyanide and gold. Dissolution in Thickeners.-The influence of a change of solution on silver dissolution has long been emphasized and most gold operators have. recognized the annoying way in which a gold ore after being agitated until nothing more can be dissolved will loosen up again when almost ready for the dump after the dissolved metal has been removed by decantation or filtration. Continuous decantation gives favorable conditions for this additional dissolution and a chance to recover most of what is thus dissolved. This is especially true if an extra tank is used in the series and barren solution added at the second tank from the end instead, of the first, as shown in Mr. Eames' Fig. 1. It can be calculated that the use of this tank will reduce the mechanical loss of cyanide by one-third and cut the gold loss as well; but the saving in gold or silver that may dissolve when the pulp is first diluted with weak solution may be as important.

Jan 4, 1917

By Howard I. Smith

The mineral trona was discovered on Government land in 1938, about 18 miles west of the town of Green River, Wyo., in the core of the John Hay, Jr., well, a test well drilled for oil by the Mountain Fuel Supply Co. in sec. 2, T. 18 N., R. IIO W., sixth principal meridian. Although no oil or gas was reported, the drilling led to a discovery of great potential economic importance and exceptional scientific interest. Trona is a relatively rare mineral found at various places in playa deposits but not previously found at any great depth. It is composed of hydrous sodium carbonate and sodium bicarbonate (Na2CO3 NaHCo3.2H2O). Pure trona con-tains the equivalent of 70.35 per cent of sodium carbonate. Total sodium computed to carbonate times 1.42 equals the percentage of trona in the absence of other sodium carbonate minerals in the sample. Analyses Two short pieces of core sent to the author a few days after the completion of the Hay well were analyzed by R. C. Wells† and found to be exceptionally Pure trona. A brief article on this discovery has already been published.1 Arrangements were then made through W. T. Nighten-gale‡ for the author to inspect and sample the core. The company log of the well included notations of sodium salt crystals from a depth of 1190 to 1820 ft. Not being able to identify all the minerals present, the author selected several specimens of the core for petrographic examinations and sampled the sections of trona for analysis. J. J. Fahey, of the Geological Survey, examined the specimens and reported most of the crystals to be a new anhydrous sodium carbonate and calcium carbonate mineral (Na2CO 3.2 CaCO3), which he named shortite,² after Maxwell N. Short." He analyzed the samples of trona, with the results shown in Table I. In addition to the 10 ft. 1 in. of trona in the first section, it is reasonable to assume that the 9 ft. 8 in. for which no core was available for sampling is either i mostly trona or some other soluble salt, but it should not be included in calculating | reserves. In the part of the core between i 1590 ft. 3 in. and 1600 ft. 4 in. the material insoluble in cold water, amounting to about 5 per cent, was estimated petrographically I to contain 70 per cent clay, 25 per cent shortite, and 5 per cent pyrite. Accompanying Minerals Fahey later secured about 600 ft, of the core for a detailed examination and study

Jan 1, 1942

By Howard I. Smith

The mineral trona was discovered on Government land in 1938, about 18 miles west of the town of Green River, Wyo., in the core of the John Hay, Jr., well, a test well drilled for oil by the Mountain Fuel Supply Co. in sec. 2, T. 18 N., R. IIO W., sixth principal meridian. Although no oil or gas was reported, the drilling led to a discovery of great potential economic importance and exceptional scientific interest. Trona is a relatively rare mineral found at various places in playa deposits but not previously found at any great depth. It is composed of hydrous sodium carbonate and sodium bicarbonate (Na2CO3 NaHCo3.2H2O). Pure trona con-tains the equivalent of 70.35 per cent of sodium carbonate. Total sodium computed to carbonate times 1.42 equals the percentage of trona in the absence of other sodium carbonate minerals in the sample. Analyses Two short pieces of core sent to the author a few days after the completion of the Hay well were analyzed by R. C. Wells† and found to be exceptionally Pure trona. A brief article on this discovery has already been published.1 Arrangements were then made through W. T. Nighten-gale‡ for the author to inspect and sample the core. The company log of the well included notations of sodium salt crystals from a depth of 1190 to 1820 ft. Not being able to identify all the minerals present, the author selected several specimens of the core for petrographic examinations and sampled the sections of trona for analysis. J. J. Fahey, of the Geological Survey, examined the specimens and reported most of the crystals to be a new anhydrous sodium carbonate and calcium carbonate mineral (Na2CO 3.2 CaCO3), which he named shortite,² after Maxwell N. Short." He analyzed the samples of trona, with the results shown in Table I. In addition to the 10 ft. 1 in. of trona in the first section, it is reasonable to assume that the 9 ft. 8 in. for which no core was available for sampling is either i mostly trona or some other soluble salt, but it should not be included in calculating | reserves. In the part of the core between i 1590 ft. 3 in. and 1600 ft. 4 in. the material insoluble in cold water, amounting to about 5 per cent, was estimated petrographically I to contain 70 per cent clay, 25 per cent shortite, and 5 per cent pyrite. Accompanying Minerals Fahey later secured about 600 ft, of the core for a detailed examination and study

Jan 1, 1942

Discussion of the paper of Ralph Hayden, presented at the Butte meeting,. August, 1913, and printed in Bulletin No. 80, August, 1913, pp. 1443 to 1467. JOHN V. N. Done, Denver, Colo.:-Mr. Hayden has placed the metallurgical profession greatly in his debt .for this valuable paper. The importance of such a complete description of the research work on which is based the building of a plant to add at least 10,000,000 lb. of copper per year to the production of the Anaconda Copper Mining Co., at small expense, will be appreciated by all our members, and especially those who are facing similar problems. The information given in regard to the treatment methods discarded will be a great help to many workers, as it is often of as much importance to know what ? not to do" as what method to adopt. I Some further comment on the tests of the Dorr thickener may be of interest, as they have led to developments which I believe will prove of great importance. Before the Dorr thickener was installed, I had shown Mr. Laist reports from the Steptoe Valley concentrator, in which it was stated that one thickener 17 ft. in diameter was the equivalent in settling capacity of twelve 8-ft. cones, although the latter-contained double the surface area.. Mr. Laist, had made careful tests on the settling capacity of in 8-ft. cone on Anaconda slime, and we naturally expected the thickener would show a much higher capacity for equivalent area. When, is Mr. Hayden stated, the tests showed no increase, I realized that we were comparing it with a cone under test conditions, while the Steptoe results were based on operative conditions, find the explanation given by Mr. Waddell for the great difference had been, that " there is only one unit to watch instead of twelve, without the constant result of feed to twelve cones becoming unbalanced. Also the one 1 1/8-in. spigot used on the Dow requires no attention compared with the dozen 3/8-in. spigots of the cones.' I realized also as a. result of the tests that the total settling area required to handle the immense tonnage of the Anaconda company would be enormous, and very expensive in view of the housing required by Montana climatic conditions. After studying the matter over, I told Mr. Laist that I believed a thickener operating in a much shallower tank would have nearly the same capacity. I asked him to test it out in the same tank filled 3 ft. deep, and stated that if my idea

Jan 11, 1913

By Geoffrey Gilbert

The Montana Phosphate Products Co., subsidiary of the Consolidated Mining and Smelting Company of Canada, operates three phosphate properties north and northeast of Garrison, Powell County, Mont. Production of all three is from the same phosphate bed, a 3 to 4-ft. member of the Phosphoria formation, whose outcrop is traceable across the mountains of the Garnet Range in a series of southeasterly pitching folds. Because of topographical differences and of variations in the attitude of the bed, each property has its own mining methods and problems. Most of the phosphate rock produced since 1930 has been shipped to the plant of the Consolidated Mining and Smelting Co. at Trail, B.C., where it is treated with sulphuric acid for conversion to phosphoric acid, which in turn is used to produce various fertilizers. History The occurrence of rock phosphate in Montana has been known since 1910, and the Garrison area was mapped by the United States Geological Survey in 1913. In the nineteen twenties William Anderson, owner of a ranch 8 miles north of Garrison, discovered phosphate on his land, and the Montana Phosphate Co., which later became the Montana Phosphate Products Co., was formed to work the deposit. Montana Phosphate Products Co. later obtained United States leases on two adjoining parcels of ground, and this combined property, known as the Anderson mine, has been the main source of Con-solidated's phosphate rock. The mine now includes an adjoining parcel leased from Anaconda and mined from the Anderson workings. In 1940, the Graveley mine, a small privately owned property 6 miles east of the Anderson, was leased from the owner by Montana Phosphate Products Co., and a U. S. lease held by Graveley on some adjoining ground was subleased. In 1943 the Luke mine, on the Mineral Hill property, 1 3/4 miles south-southwest of the Graveley, a U. S. lease, which previously had produced a few thousand tons, was optioned from the lessees by Montana Phosphate Products Co., and is now being developed. At both these mines the rock is appreciably higher grade than at the Anderson mine. Geology The Phosphoria formation is the Permian member of an extensive sequence of Paleozoic and Mesozoic rocks. It is underlain by Pennsylvanian (Quadrant) quartzite and Mississippian limestone, and overlain without any marked unconformity by Jurassic (Ellis) shale and Cretaceous shale and sandstone. In the Garrison area, the Phosphoria itself consists mainly of about 50 ft. of gray to yellow chert. Immediately below the chert is the phosphate, usually 3 to 4 ft. thick. Below the phosphate occur a few

Jan 1, 1948

By Geoffrey Gilbert

The Montana Phosphate Products Co., subsidiary of the Consolidated Mining and Smelting Company of Canada, operates three phosphate properties north and northeast of Garrison, Powell County, Mont. Production of all three is from the same phosphate bed, a 3 to 4-ft. member of the Phosphoria formation, whose outcrop is traceable across the mountains of the Garnet Range in a series of southeasterly pitching folds. Because of topographical differences and of variations in the attitude of the bed, each property has its own mining methods and problems. Most of the phosphate rock produced since 1930 has been shipped to the plant of the Consolidated Mining and Smelting Co. at Trail, B.C., where it is treated with sulphuric acid for conversion to phosphoric acid, which in turn is used to produce various fertilizers. History The occurrence of rock phosphate in Montana has been known since 1910, and the Garrison area was mapped by the United States Geological Survey in 1913. In the nineteen twenties William Anderson, owner of a ranch 8 miles north of Garrison, discovered phosphate on his land, and the Montana Phosphate Co., which later became the Montana Phosphate Products Co., was formed to work the deposit. Montana Phosphate Products Co. later obtained United States leases on two adjoining parcels of ground, and this combined property, known as the Anderson mine, has been the main source of Con-solidated's phosphate rock. The mine now includes an adjoining parcel leased from Anaconda and mined from the Anderson workings. In 1940, the Graveley mine, a small privately owned property 6 miles east of the Anderson, was leased from the owner by Montana Phosphate Products Co., and a U. S. lease held by Graveley on some adjoining ground was subleased. In 1943 the Luke mine, on the Mineral Hill property, 1 3/4 miles south-southwest of the Graveley, a U. S. lease, which previously had produced a few thousand tons, was optioned from the lessees by Montana Phosphate Products Co., and is now being developed. At both these mines the rock is appreciably higher grade than at the Anderson mine. Geology The Phosphoria formation is the Permian member of an extensive sequence of Paleozoic and Mesozoic rocks. It is underlain by Pennsylvanian (Quadrant) quartzite and Mississippian limestone, and overlain without any marked unconformity by Jurassic (Ellis) shale and Cretaceous shale and sandstone. In the Garrison area, the Phosphoria itself consists mainly of about 50 ft. of gray to yellow chert. Immediately below the chert is the phosphate, usually 3 to 4 ft. thick. Below the phosphate occur a few

Jan 1, 1948

By Edward Saibel

THE object of this study is to investigate the effect of prior tensile strain on the fracture stress of a metal. This is done in a theoretical manner starting from the point of view developed by the author in his thermodynamic theory of the fracture of metals. The results are compared with experimental findings and a rational interpretation is given to work that shows the variation of fracture stress with prior tensile strain. THEORY OF FRACTURE In the thermodynamic theory of the fracture of metals developed earlier,1 it was shown that a critical strain energy per unit volume exists. This is characteristic of the material and may be calculated from basic thermodynamic data. When the area under the flow curve reaches this characteristic value, fracture occurs. The general criterion for fracture is expressed in the form u ± uo = JLm?AV/V [1] where Lm, is the latent heat of melting of the unit volume, ?V/V is the ratio of the change in volume of the unit volume to the original unit volume on passing from the solid to the liquid state, [uo] is an initial energy density, and J is a conversion factor, which changes energy from heat to mechanical units. As a first approximation, it will be assumed that the stress-strain curve is the straight line that extends from the point of maximum load onward, extrapolated back to the axis of zero strain, for example, line AC of Fig. 1. If the point of intersection of the straight line with the axis of zero strain is represented by so, and the slope of the straight line is p, the analytic form of the flow curve is [s = s + pd [2]] and the strain energy per unit volume evaluated from [JvdS] becomes (vsod + pd2/ 2). When this latter term reaches the critical value JLm?V/V (designated hereafter by M), it is assumed that fracture occurs. This leads to the following expression for the fracture stress: [s1 = \/C r.2 + 2Mp [31] The strain at fracture may be calculated from Eqs 2 and 3. It is assumed in this paper that the initial energy density is either zero or that it may be neglected. Furthermore, the complicated states of stress and of strain existing in the necked region of the tensile specimen after "necking" has occurred will also be neglected for the present, so that average conditions will be assumed to prevail. FLOW AND FRACTURE CURVES Ludwig2 attributed to materials two fundamental properties: (I) a resistance to flow and (2) a resistance to fracture. He reasoned that at each instant the

Jan 1, 1947

By Fred Wise, C. W. Wark

THE Getchell mine, a comparatively recent gold discovery, is in the old Potosi mining district, Humboldt County, Nevada. All ore is mined from open pits using Diesel shovels and gasoline trucks. Two types of ore are mined, oxide and sulphide. Oxide ores are siliceous or shaly; sulphide ores either gougy, siliceous or shaly. In mining, the sulphide ore is segregated into hard and gougy ore, because the gouge must be dried before it can be crushed. The oxide ore is not segregated. GENERAL METALLURGY The oxide ore is the leached outcrop that overlies the sulphide ore body. All of the iron and arsenic sulphides found in the sulphide ores have been thoroughly oxidized. The sulphur and arsenic have been leached out while the iron is present as hematite and limonite. The oxide ore is amenable to direct cyanidation, and although no visible free gold is present it is released at a comparatively coarse grind. The sulphide ore is more refractory, since the gold is all of micron size and some of it is locked in fine sulphides. It has been established microscopically that the free gold is coated with an impervious shell, which is probably some form of iron compound. The sulphide ores contain from 1.5 to 2 per cent of arsenic, which is present as orpiment and realgar with minor amounts of arsenopyrite. The orpiment and realgar are of a later mineralization than the gold and are barren. Roasting and washing of the sulphide ore prior to cyanidation is necessary to eliminate the arsenic, to alter the gold coating from an insoluble form to a soluble form, and to release the gold associated with the fine sulphides. Washing the ground calcine in weak sulphuric acid, trona, or hot water are beneficial in the order named, but to date the water is the best from an economic standpoint. Metallurgical tests as well as plant practice indicate that a certain amount of gold cannot be recovered even by going beyond economic practices. On this basis metallurgical results are viewed in the light of an optimum tailing rather than a percentage of extraction. MILLING PRACTICE Crushing (Fig. 1).-There are three primary ore bins, one each for oxide ore, gougy sulphide ore, and hard sulphide ore. In front of each bin a substantial yard is maintained, which makes it possible to stockpile 2500 tons of oxidized ore, 1000 tons of hard sulphide ore, and 1000 tons of gougy sulphide ore. The bins are fed by a 60-hp. caterpillar bulldozer from the stockpiles. Fig. 1 shows the method and

Jan 1, 1940

By R. W. Raymond

Franklin Guiterman was born March 7, 1856, in Cincinnati, Ohio, where his father, William Guiterman, was at that time engagcd in the wholesale dry-goods business. Both of his parents were natives of Bavaria, but the inspiration of America was upon them, as they gave to their son a peculiarly American name, symbolizing thrift, individualism and scientific knowledge. Franklin Guiterman received his general education in the grammar schools and the Hughes High School of Cincinnati. He finished the latter course in the early 70's of the last century, when the great demand for mining and metallurgical experts in this country naturally led his parents to direct his further studies in that direction. Accordingly, he went to Europe, and studied at the Royal Saxon Mining Academy of Freiberg, where he completed the course in 1877, at the age of 21, and returned to the United States to engage in mining and metallurgical practice. Going to Colorado, he became assayer for the Terrible mine, at Georgetown, and in 1878, for the Little Chief mine at Leadville. The position of assayer, particularly at that period and in that region, was the door to much valuable knowledge of mines and ores. Besides learning the nature and value of the different classes of ore from the mines of his own company (if he was employed by a company) the assayer, had the first chance, through his outside customers, of seeing and testing the specimens brought by prospectors, and thus learning of important new discoveries. Moreover, if he possessed metallurgical knowledge, he might advance to the position of a metallurgical manager. Guiterman stayed in Leadville four years, and during that period was assayer or chemist for several different companies. Then for about a year he superintended copper-mining operations at Hartville, Wyo. In 1884, he had charge of sampling works at Silverton, colo.—an admirable opportunity for gaining wide knowledge of the varied ores of the San Juan country. In 1885, he was Superintendent of the Mingo plant of the Pennsylvania Lead Co., at Sandy, near Salt Lake City, Utah. The foregoing list of employments, each occupying not more than a year, certainly looks like the history of a rolling stone, gathering no moss. But the cause of these frequent changes was not inefficiency in each new position. In that time and period, a man who lost his place for such a reason was not likely to get another in the same neighborhood might away. And as for gathering "moss," the kind of "moss" that

Jan 1, 1918

By J. B. Cohen

In an investigation of the microstructure of shock-loaded metal specimens1 C. S. Smith found that there was little distortion of grain boundaries or change in external dimensions, although the hardness corresponded to that produced by severe rolling. Furthermore, the hardness of individual grains was independent of the deformation structures present; grains with no markings were as hard as those heavily populated with markings. These markings which resemble twins do not appear in copper until high shock-loads of the order of 200 kb are applied. It appears that due to the high velocity of a shock wave and its sharp front, heavy deformation takes place on a submicroscopic scale. In this work an attempt was made to examine this deformation, particularly at a load below which macroecopic markings appear. The broadening of 200 and 400 diffraction peaks was examined from the face of a poly crystalline sample normal to the direction of the shock wave. These peaks were chosen because the elastic constants in copper are such that residual strains would be greatest in the <100> directions; hence, the strain-broadening contribution to these peaks would be large in comparison to other sets. Also the broadening due to stacking faults and microtwins would be greatest with this set.2 A complete Fourier analysis of these peaks was made, as described by warren,&apos; using the Stokes correction with peaks from an annealed sample.3 With the aid of the U. S. Army Ordnance Corps EDVAC computer and a curve matching program, sixty sine and sixty cosine coefficients were obtained for each peak. The last of these was about 1.5 pct or less of the largest coefficient, indicating good representation. Transverse sections from a 1.5 in. rod of as-drawn electrolytic tough-pitch copper were reduced in cross-sectional area about 50 pct by cross rolling. Disks 1.5 in. in diam were recrystallized at 275 °C for 30 min and then at 300°C for the same time. The faces were polished and deeply etched in nitric acid to remove 25 mils. The grain size was 0.02 mm. Laue back-reflection patterns indicated the sample was well recrystallized. The two diffraction peaks from this sample were recorded on a Norelco diffractometer using filtered copper radiation. Peak intensities were kept less than 600 cps to assure linearity of the counter and circuitry. This sample was then placed between two rods of the same material and diameter. The top rod was 2.25 in. long and the bottom rod 1 in. long. (In

Jan 1, 1961

By Howard I. Smith

THE mineral trona was discovered on Government land in 1938, about 18 miles west of the town of Green River, Wyo., in the core of the John Hay, Jr., well, a test well drilled for oil by the Mountain Fuel Supply Co. in sec. 2, T. 18 N., R. 11o W., sixth principal meridian. Although no oil or gas was reported, the drilling led to a discovery of great potential economic importance and exceptional scientific interest. Trona is a relatively rare mineral found at various places in playa deposits but not previously found at any great depth. It is composed of hydrous sodium carbonate and sodium bicarbonate (Na2CO3.NaHCO3.2H2O). Pure trona contains the equivalent of 70.35 per cent of sodium carbonate. Total sodium computed to carbonate times 1.42 equals the percentage of trona in the absence of other sodium carbonate minerals in the sample. ANALYSES Two short pieces of core sent to the author a few days after the completion of the Hay well were analyzed by R. C. Wells† and found to be exceptionally pure trona. A brief article on this discovery has already been published.1 Arrangements were then made through W. T. Nightengale‡ for the author to inspect and sample the core. The company log of the well included notations of sodium salt crystals from a depth of 1190 to 1820 ft. Not being able to identify all the minerals present, the author selected several specimens of the core for petrographic examinations and sampled the sections of trona for analysis. J. J. Fahey, of the Geological Survey, examined the specimens and reported most of the crystals to be a new anhydrous sodium carbonate and calcium carbonate mineral (Na2CO3.2CaCO3), which he named shortite,2 after Maxwell N. Short.* He analyzed the samples of trona, with the results shown in Table i. [ ] In addition to the 10 ft. I in. of trona in the first section, it is reasonable to assume that the 9 ft. 8 in. for which no core was available for sampling is either mostly trona or some other soluble salt, but it should not be included in calculating reserves. In the part of the core between 1590 ft. 3 in. and 1600 ft. 4 in. the material insoluble in cold water, amounting to about 5 per cent, was estimated petrographically to contain 70 per cent clay, 25 per cent shortite, and 5 per cent pyrite. ACCOMPANYING MINERALS Fahey later secured about 600 ft. of the core for a detailed examination and study

Jan 1, 1942

By F. M. Waring

produced when zinc is substituted for a certain amount of tin are decidedly unsatisfactory. The substitution of aluminum for tin is entirely impractical, and such castings are worthless. This does not, however, exhaust all the possibilities of substituting other metals for tin in the copper-tin-lead alloys, but it is my opinion that the substitution of any other metals, in those alloys, can be made only by sacrificing the quality of the alloy. The possibility of substituting alloys of an entirely different type presents an attractive field for research. The copper-tin-lead alloy has attained its position as the most desirable bronze bearing alloy, but this does not mean that some other alloy may not be found which may give equally good or better results. In the search for such a substitute alloy it should be borne in mind that a bearing metal should possess the following properties: (1) It should be sufficiently rigid to support the load or resist the impact, but yet not so brittle that it will easily crack. (2) It should have as great a yielding or plastic nature as is consistent with its ability to support the load or resist the impact without deformation of the bearing as a whole. (3) The ideal structure combines a hard matrix to support the load and a softer metal or alloy contained within such matrix, to permit the bearing surface to adjust itself to irregularities of service. (4) It should be easy to handle in the foundry and machine shop. (5) It should be capable of being remelted without deterioration. (6) For use in babbitt-lined bearings, it should be capable of being tinned, so that the babbitt can be applied thereto. (7) It should have good heat conductivity in order to dissipate the heat generated by friction. Pennsylvania Railroad Anti-friction and Bell Metals F. M. Waring," Altoona, Pa.—Thc necessity for conserving tin has recently been very forcibly brought to the attention of all consumers, and efforts are now being made to reduce the tin content in certain alloys or to substitute other alloys not containing tin. The approximate composition of the non-ferrous alloys in general use on the Pennsylvania Railroad are given in the accompanying table. Phosphor bronze is used principally for rod bushings, main-rod brasses, and crosshead shoes. Ex. B bronze is used to a small extent for backs of car and coach bearings, but the majority of these are now made of the car-journal bronze, which contains, on the average, about 5 per cent. tin.

Jan 1, 1919

By K. Verghese, R. W. Rousseau, R. P. Gardner

A radioactive tracer method and a size-discretized, mass balance model are formulated and demonstrated in a feasibility experiment for the determination of crystal growth rates in MSMPR crystallizers. The system studied is aqueous KN03 with K-42 as the radioactive tracer. The results indicate that the method should prove to be very valuable for this application, particularly when systems exhibiting size-dependent growth rates are of interest. An indicated refinement to the tracer method is the simultaneous use of an additional tracer in the liquid to determine the amount of radioactivity from the liquid that is adsorbed on the samples of filtered crystals.

Jan 1, 1980

By E. C. Wilson

The knowledge concerning the lubrication of open gearing for mining machinery has contained many unknowns and at its best has relied to a great degree on a "Rule of Thumb" procedure. It will be within the scope of this paper to explain what we have learned to date and what must be learned in the future. Action of Two Gears in Mesh Let us review some of the basic fundamentals concerning the action of two gears during mesh. Most of the gears we use are involute and may be spur, helical, or herringbone. The gear contact is a combination of rolling and sliding action.

Jan 12, 1968

By Leonid Bryner

For many years, geologists have inferred a connection between the evolution of the earth&apos;s crust and ore deposition, a connection coming under the heading of metallogeny. In recent years the concept of metallogeny has assumed major importance in the exploration planning of Russian geologists in their quest for new mineral sources. As defined by Radkevich, metallogeny is "the science which studies the laws governing the distribution of ore deposits in the earth&apos;s crust." However, since it can be argued that metallogeny does not contain enough certitude to be classified as a "science," it would be more appropriately defined as the study of metallogenic provinces, and metallogenic epochs.

Jan 6, 1963

By William Braden

IT is obvious that the choice of the method to be employed in the handling of blast-furnace slags and mattes depends upon local facilities and conditions which may indicate as advisable some particular plan. As a result of the variety of such conditions hardly any two smelters use identically the same method, though they be located only a few hundred feet apart. For instance, of the several plants in Leadville, Colorado, each has a more or less distinctive system. The same is true of Salt Lake City and vicinity. In view of this it is evident that the existing diversity of practice cannot be accepted, prima facia, as evidence

Jan 1, 1897

YEAR or ELECTION 1913. FRANK DAWSON ADAMS Montreal, Canada. 1933. KARL EILERS New York, N. Y. 1922. FEDERICO GIOLITTI Q. Torino,Italy. 1906. SIR ROBERT A. HADFIELD London, England. 1921. FRANK WILLIAM HARBORD London, England. 1917. HERBERT HOOVER New York, N. Y. 1931. WALDEMAR LINDGREN Cambridge, Mass. 1921. C. MCDERMID London, England. 1913. EZEQUIEL ORDOAEZ Mexico City, Mexico 1935. ROBERT PEELE New York, N. Y. 1938. A. M. PORTEVIN Paris, France. 1937. Joan V. W. REYNDERS New York, N. Y. 1937. GEORGE S. RICE Washington, D. C. 1911. ROBERT H. RICHARDS Cambridge, Mass. 1934. T. A. RICKARD Victoria, B.C., Canada. 1933 Cambridge, Mass.

Jan 1, 1938

By Thomas E. Wayland

AN isopachous map is one on which lines connect points of equal thickness of a given unit. This type of map is used by the Florida Phosphate Project of the U. S. Geological Survey to represent the economic phosphate deposits known as matrix and the waste material, or overburden, that overlies the matrix. The top of the bed on which the phosphate was deposited is known as the basement and a subsurface contour map of this old buried erosion surface is known as a basement map. Recent experiments have been made in preparing maps that show tonnages and grades of the phosphate content of the matrix.

Jan 11, 1951

CANADA, which appears to be growing into one big mining camp, may soon be the background for another impressively large iron ore development. And again it will be Fenimore Iron Mines who will be the motivating force. Dr. J. A. Retty, Fenimore president, who was one of the important figures in the development of Labrador iron deposits, predicts a great future for property on the west coast of Ungava Bay in deep northern area of New Quebec. Fenimore properties consist of a 200 sq mile concession in addition to several hundred claims over about 112 miles along the Labrador trough, mainly in the Ungava Bay region.

Jan 5, 1953