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By Sir Robert Hadfield

(New York Meeting, February, 1913.) THE Hadfield method of producing sound steel ingots has been the subject of a paper 1 read before the Iron and Steel Institute, so that it will be unnecessary to describe it fully here. The object of the method is to make possible the production of steel ingots in which the pipe is almost entirely obliterated, and it is applicable particularly to the production of sound ingots, from which good rails could be rolled. The method in brief consists in casting the ingots on cars, usually with the small end down. Each ingot mold is provided with a sand top, rammed up in the well-known manner. After the mold is filled to the desired height with steel, a layer of slag about 0.5 in. thick is placed upon it and the balance of the mold is then filled with charcoal. Then, through suitable piping, an air blast is directed in numerous jets upon the charcoal, which is burned thereby, the combustion supplying additional beat to the top of the ingot, which helps to keep the top fluid and to retard its solidification, while the lower parts are rapidly losing heat by its transfer to the mold. By-one plan the ingots are cast in molds placed upon bogies, movable trucks, or platforms, in the position A, Fig. 1. The ingots are cast vertically on bogies, say four or more ingots on each bogie, as may be found most convenient, and the upper surface of the steel is maintained in a molted condition during the transit of the ingots from the casting pit to the stripper. This is effected by a series of air pipes, for example, three in number, with jets or holes on the under surface of such pipes, placed preferably horizontally, arranged in such a manner as to cause jets of air to impinge on the upper surface of the ingots. These holes or jets are made throughout the entire length of the overhead pipes, the length of such pipes being

Jan 4, 1913

By J. W. Gabelman

A study of spatial relations between uranium and other metal deposits and hydro thermally altered rocks in western Colorado demonstrated districtwide and regional zoning. The pattern was later found repeated elsewhere in the Western Hemisphere Cordillera. District mineralization centers are pipelike bodies of pervasively altered rock from which intensity-temperature-pressure gradients decreased outwardly. Uranium occurs in several zonal environments but usually is economic only in outermost zones. The general similarity of zones throughout the tectoni-cally and metallogenically uniform Cordillera may reflect a consistent hydrothermal process involving zoning. By determining positions of zones it should be possible to select for examination the most favorable small portions of districts or provinces. Mineralogical zoning has been discussed by Lindgren,l3 Graton,lo Emmons,' Blanchard,' Park and many others. It is commonly found to some extent in most mineralized areas. The existence of nonmetallic alteration envelopes around lode metal deposits and their relation to metallization were first emphasized by Lovering,l4 Burbank, Sales and Meyer," Sales,2o McKinstry,I7 Lovering and others15 and Schmitt. Also, large areas of nonmetallic alteration containing porphyry-type replacement metal disseminations have long been recognized and are described by Schwartz,25-28 Kerr and others" and Gilully. In some districts, e. g., Bingham Canyon, Utah, and Santa Rita, N.M., base metal lode deposits and their alteration envelopes are zoned around large altered areas which contain porphyry copper replacement disseminations; however, the spatial and genetic relations between lodes and replacement disseminations and their associated alterations do not seem to have received sufficient attention. Bodies of altered rock containing porphyry-type replacement disseminations are many times larger than the alteration envelopes containing lode deposits. The two types are rarely superimposed. They occur adjacent to or independent of one another, but they are believed to be related through the mechanism of zoning as suggested by Gabelman and Boyer. 5'6 Most of the significant lode metal deposits are distributed around central pipelike bodies of strong, pervasive, nonmetallic alteration which may or may

Jan 1, 1962

By Oswald J. Heinrich

The serious objections to the Leblanc soda process may be enumerated as follows: 1st. The total loss of sulphur employed, equal to about one-third of soda produced. Various processes have been proposed to regain this sulphur, but none have come into practical operation on a large scale. 2d. The great balk of waste products, equal to nearly twice the amount of soda, which forms a serious annoyance about the works. 3d. The complicated series of operations necessary. 4th. The large amount of labor and fuel required. 5th. The prodoction of noxious gases which necessitate extensive condensing arrangements. 6th. The large capital necessary for the . erection and maintenance of the plant, These objections have long been recognized, and many attempts have been made during the last thirty or forty years, to discover and introduce a cheaper and more direct method for the manufacture of this important staple. The reaction between bicarbonate of ammonia and common salt, whereby bicarbonate of soda, insoluble in a solution of chloride of ammonium, is precipitated, has been closely studied for the last twentyfour years, on account of its simplicity and the purity of the product it affords. This ammonia-soda process is now so far developed, that while it is not in position to entirely replace the Leblanc process, yet it can successfully compete with it where the conditions and localities are favorable. The advantages of the ammonia-soda process may be summed up as follows : 1st. It is independent of the essential agent in the Leblanc process, via., sulphuric acid, and hence can be established in those localities where salt is abundant, and yet where sulphuric acid could not be made, or where it could not be transported profitably. 2d. The ammonia-soda process being a " wet" process, the evaporation of salt brines to obtain the solid salt required in the Leblanc process, is rendered unnecessary. 3d. The direct conversion of chloride of sodium into bicarbonate of soda, which can readily be converted into the maketable monocar-

Jan 1, 1879

By Joseph W. Richards

This method of briquetting flue-dust, or flue-dust mixed with fine ores, or, in a few exceptional cases, coke-dust, has come into large commercial use in Europe, and a small plant is already in operation in the United States. It promisea to become of such great importance to the iron industry of the United States that the following description will certainly interest the majority of our pig-iron producers. Discovered in 1908, the process Tests upon the observation of Dr. Schumacher that blast-furnace flue-dust, while possessing of itself no binding or cementing properties, acquires strong cementing properties if mixed with a very small amount of certain salt solutions, the amount of which is so small that the resulting cementation appears to be rather by catalytic action of the salts added than by the mass-action of such chemicals. To be more specific, fresh blast-furnace flue-dust mixed with from 5 to 10 per cent. of its weight of magnesium chloride or calcium chloride solution—that is to say, with from 0.25 to 2 per cent. of its weight of magnesium chloride or calcium chloride—acquires the property of setting within a short time, from 15 to 60 min., and forming a hard cemented briquette. Alkaline solutions appear to have no action such as described, and they even interfere, if present, with the action of the magnesium and calcium solutions. When treated in this way the flue-dust briquette sets very hard, apparently from pure excess of cementing- and setting-power. It is, therefore, possible to mix with the flue-dust a considerable proportion of inert ore or like material, which has no setting-power by this process, and thus to make a compound briquette containing large quantities of ore mixed with flue-dust, but in which the flue-dust may be regarded as the cement or binding-material. A particularly strongly cementing flue-

Jan 1, 1913

By Earl A. Trager

The broad picture of world petroleum production at the present time is one of an excessive supply. In any consideration of corrective measures to be applied in the future, it will be necessary to include all the producing areas of the entire world. To illustrate, United States production during 1931 was 48 million barrels1 less than 1930, whereas world production exclusive of the United States increased, owing principally to increases in Russia, Rumania and Persia. Domestic Peoduction Let us first consider the domestic production situation. Due to the fact that United States production was maintained below current demand, about 40 million barrels of oil were withdrawn from storage during 1931. Consumption increased about 1.5 per cent over 1930, which is less than the recent annual rate of increase of 8 to 11 per cent. If the machinery to prevent waste in the petroleum industry operative for more than a year will continue during the coming year and drilling is held to the 1931 level, there will be a decided improvement in the domestic situation by the close of 1932. This will be due in large measure to the drastic reduction in exploratory work and drilling which has been in effect for more than a year. Looking ahead for two or more years, probably there will be a shortage of domestic production in relation to domestic demand, unless there are discovered several large pools comparable to Oklahoma City or East Texas. Were the United States isolated, our problems in so far as petroleum production is concerned might be considered well along the road to recovery. To maintain this perspective will require the cooperation of foreign producers in the future, or protection of United Statcs markets from foreign invasion. Let us review briefly the present situation in the United States. East Texas has been the most important factor during 1931. The large initial production of individual wells and the rapid rate of drilling

Jan 1, 1932

By T. S. Lundy, J. I. Federer

A graphical method has been developed and tested for separating the effects of grain boundary and lattice diffusion in polycrystalline materials. The method is based on the assumptions that for unidirectional diffusion from a plane source of radioactive material, the penetration of activity far into the specimen from the source is due solely to grain-boundary effects, and 2) pure grain-boundary penetration is described by a linear plot of log activity vs the perpendicular distance x from the source. The former is based on the fact that at any temperature the grain-boundary diffusion coefficient is always very large relative to the lattice diffusion coefficient; and the latter is based on the derivation of Fisher.1 Using these criteria along with appropriate penetration data (in this case, data for the diffusion of Cb95 in pressed and sintered UO2) one first plots the data as log activity vs x2 and as log activity vs x, as shown by curves 1 and 2, respectively, in Fig. 1. A tangent line to curve 2 for large x (curve 3) is then transferred to the x2 plot as curve 4. The subtraction of curve 4 from curve 1 yields curve 5 which represents only lattice diffusion and may therefore be related to the diffusion coefficient by using the appropriate solution to Fick's second law. It should be noted that the method has inherent inaccuracies for small and large values of x2 and only the subtraction at intermediate values can be used. For the illustrated specimen the calculated diffusion coefficient is 3.4 X 10-11 sq cm per sec at1445°C while data using a single crystal of UO2 at the same temperature yielded a value of 2.9 x 10-11 sq cm per sec.2 The same method of subtracting grain-boundary diffusion effects to obtain lattice diffusion coefficients has been successfully used to determine self-diffusion coefficients of Th230 in polycrystalline thoria.

Jan 1, 1962

COLUMBIA SECTION STANLY A. EASTON, Chairman, FREDERIC KEFFER, Vice-Chairman, L. K. ARMSTRONG, Secretary-Treasurer, P. 0. Drawer 2154, Spokane, Wash. D. C. LIVINGSTON FRANK A. Ross The first meeting of the Columbia Section was held on March 24, as a part of the 1916 Northwest Mining Convention which was held under the -auspices of the Spokane Mining Men's Club assisted by the Spokane Chamber of Commerce, the technical program being in charge of the Spokane Engineering and Technical Association assisted by the local sections of the A. I. E. E., A. S. C. E., and A. I. M. E. The program of the successive sessions was carefully arranged with view to its application to mining, and in addition to the technical program there were exhibits of ores, minerals, devices, etc., of interest to the delegates, who numbered over 500. A portion of the program was also arranged with special reference to the requirements of the prospector and miner. A reception, a banquet, a complimentary luncheon, a regular daily call' of the Stock Exchange, a visit to the High Schools and to one of the substations of the Washington Water Power Company and to the Union Iron Works kept the visitors entertained, the ladies being looked after by a special committee of ladies who held open house during the entire week. Several important resolutions were passed by the Convention and one by the Columbia Section, A. 1. M. E. With Stanly A. Easton, chairman, presiding, the Columbia Section, American Institute of Mining Engineers, occupied the time between 2.00 and 5.30 p.m., March 24th, the Moorish room of the Spokane hotel being filled with members and their guests. "The Apex Law and the Mineral Surveyor" was a paper presented by F. W. Callaway and generally dis-cussed because of its local application in the Coeur d'Alenes, the conclusions being reached after expensive litigation between two of the large mining operators in that district.

Jan 6, 1916

By Robert W. Hunt

I have frequently stated that while the chemical composition of steel is important, yet even greater importance is connected with the mechanical and heat treatment of the metal. During the past year I encountered such a positive example of that fact that I deem it worth putting upon record. A prominent railway system divided an order for open-hearth steel rails between two steel works, both of which are under the control of the same corporation; giving to one about 18,000 tons, and to the other 7,500 tons of the same section and to be made under the same specifications. The rolling results obtained in the two mills varied so widely that a study of the figures is intensely interesting and serves to illustrate the advantages obtained by carefu1 ingot casting, and, quite as pertinently, the possible benefits of careful subsequent heating and rolling with moderate reductions in the rolling process. The smaller order was rolled complete in four installments during the same months that the larger order was being made in six separate installments; but, to permit of exact comparisons, the totals of the four installments (completing the order with the mill which I will call A) are given with the totals of the first four installments of the larger order, made by the mill designated as B. These rolling results are: Mill A. Mill B. Number of rollings,............................................ 4 4 Total number of rails rolled................................ 18,278 27,832 Percentage of rails cut to short lengths because of flaws near ends, etc......................................... 0.7 7.6 Percentage of rails made second quality for flaws, etc. 0.9 6.3 Percentage of rails scrapped for flaws, etc............... 0.6 4.5 Percentage of rails scrapped for failure at drop test... none 3.4 It should be stated that the figures given above cover all the reasons for putting the rails in the classes stated, Thus a part of the percentage of rails cut to short lengths may have been

Jan 1, 1914

By L. G. Carpenter, D. E. Garrett

Probably the largest single tungsten deposit in the U. S. is one that has yet to produce any tungsten; it is not even listed in tables showing U. S. reserves. This deposit is at Searles Lake, Calif., where the brine contains about 70 ppm WO,. Small though the concentration is, the amount of brine in the lake is so great that it is estimated at 170 million lb of WO3 (8.5 million units), equaling the total of all other known reserves in the U. S. This dry lake is located in the basin formed by the Argus and Slate ranges in the northeastern corner of the Mojave Desert (Fig. 1). It consists of a massive salt body some 35 sq miles in extent, varying in thickness from 0 to 120 ft and containing more than 3 billion tons of salt. A central section of about 8 sq miles is exposed salt; the remaining area is overlain by mud. Except for the exposed sodium chloride (10 to 15 ft thick) the body consists of a very complex and heterogenous mixture of soluble crystals, containing at least eight major phases. It is only about 53 pct solid, the voids being occupied by a dense brine which is the raw material for two chemical companies operating in the valley. The deposit is believed to be made up of salts present in the runoff waters from the last two ice stages. Searles Lakes was the third in a chain of five lakes that received waters from the Owens Valley drainage of the Sierra Nevada Mts. After leaving Owens Lake the waters could flood in succession into the Indian Wells, Searles, Panamint, and Death valleys (Fig. 2). During the first two ice stages of the Pleistocene Epoch most of the waters eventually arrived at Death Valley; consequently the lower 3300 ft of Searles Valley contain only mud

Jan 1, 1960

Illinois is rightly known as containing the coal deposit of which the first record in the United States was made. Joliet and Marquette saw "charbon de terre" along the Illinois River in 1673;1 LaSalle saw "mines de charbon" along the same stream in 1679; and Hennepin reported having "found in Several Places Some Pit-Coal" in 1682.2 In 1687 Jontel, in writing of the Illinois River country said, "along the river are coal pits, the coal whereof has been try'd and found very good."3 J. Carver reported the northern parts of the Mississippi River valley, "containing lead, copper, iron, coals, etc." in 17664 evidently referring to the Illinois country. Croghan, in the same year, saw coal along the Wabash River, near the mouth of the Vermilion in Indiana, but not far from Danville. Capt. Philip Pittman in his journey up the Mississippi in 1770 reported that "great pieces of coal are constantly found on the sand-banks, from whence it may be concluded, that there are coal-mines on the upper parts of the Mississipppi."5 This coal could only have come from the Illinois or Big Muddy Rivers. Morse, in 1798, refers to great quantities of coal on the upper branches of "the Father of Waters," and "on the Illinois River is a coal mine, which extends for half a mile along the middle of its banks."6 While, undoubtedly, some coal was used locally in various places, no records have been left of it and the first definite one is that in 1809 William Boon shipped some coal from the Big Muddy River, in Jackson County, to New Orleans, which was the first coal exported from Illinois.1 There has been considerable discussion as to this first shipment, whether it was made in 1809, 1810 or 1812. The records of arrivals of: boats in New Orleans in those early years is specific as to date, name of craft and name of captain, but no mention is made of cargo carried. William Boon arrived

Jan 1, 1942

By R. J. Evans

THE Combined Metals Reduction Co.'s plant is at Bauer, Utah. It was built primarily to treat ore from the Combined Metals mine at Pioche, Nevada. Shortly after its completion, the company acquired the old Honerine mine, and ores from this mine, as well as custom ores from widely scattered districts, are now being treated at the Bauer plant. PIOCHE ORE The Pioche ore, which comprises about 50 per cent. of the mill feed, occurs as a replacement of an impure thin-bedded limestone. The lime beddings are separated by thin layers of micaceous shale containing appreciable quantities of sericite and graphite. The ore is an exceptionally fine-grained, dense mixture of minerals and gangue, assaying approximately 0.03 oz. gold, 7.2 oz. silver, 7 per cent. lead, 15 per cent. zinc, 16 per cent. iron, 29 per cent. insoluble and 1.5 per cent. lime. Of the total lead 7 per cent. is in the form of sulfate and carbonate. Approximately 10 per cent. of the ore consists of chert nodules impregnated with barren pyrite; the nodules average 0.8 mm. in size, and are extremely hard, compared with the other constituents of the ore. Microscopic examination of Pioche ore ground to 80 per cent. minus 150 mesh shows pyrite, sphalerite and galena still attached. EARLY ATTEMPTS AT ORE DRESSING Metallurgists, both professional and those working for private companies, have been more or less familiar with the Pioche ore since 1913; in fact, a total of 35 commercial and plant laboratories experimented with the ore between 1913 and 1921. The work during this period was decidedly negative, it being seemingly impossible to effect a satisfactory separation of the valuable minerals into marketable products. In 1913, it was recognized that fine grinding-that is, about minus 200 mesh-was required to liberate the minerals from one another, and from the gangue, but such fine grinding was not considered practicable at this time.

Jan 1, 1928

By J. V. Richards

(Canal Zone Meeting, November, 1910,) THE Altar district, State of Sonora, Mexico, is for the most part a desert with but little rain-fall and few running streams. On account of this scarcity of water it is necessary for the natives to " dry-wash" the placer-gravel, and the object of the present paper is to describe some of the more common Mexican dry-washing devices. My observations were confined to a property known as Las Palomas placers, 15 miles from the Gulf of California and about 150 miles south of the United States border; a brief description of which property may be of interest as illustrating what is, perhaps, a typical Sonora dry placer. It is said that as long as a century ago the Yaqui Indians discovered rich cement-gravel, known as argo masa, at Las Palomas, and that there has been a more or less steady production of gold from the property ever since. The argo masa is a fairly-coarse gravel, the pebbles being quite firmly held together with a lime cement. Gold is scattered through this cement in particles ranging from fine specks to pieces several grams in weight, and occasional large nuggets are encountered. The contents vary so widely that it is difficult to estimate the average value, but returns of from $10 to $50 per cubic yard are common, and it is doubtful if the Indians considered anything less than from $4 to $5 a yard as "pay dirt." This argo masa occurs in channels varying in thickness from a few inches to several feet, and in width up to 300 ft.. These channels are continuous and are probably ancient stream-beds. They are for the most part covered with an over-burden of a more recent gravel, varying from 30 to 50 ft. thick, and the fact that this over-burden contains values as high as $1.50 per cubic yard, and yet was not worked by the Indians, shows that their idea of what constituted pay-ground was high.

Apr 1, 1911

By Oswald J. Heinrich

THE serious objections to the Leblanc soda process may be enumerated as follows : 1st. The total loss of sulphur employed, equal to about one-third of soda produced. Various processes have been proposed to regain this sulphur, but none have come into practical operation on a large scale. 2d. The great bulk of waste products, equal to nearly twice the amount of soda, which forms a serious annoyance about the works. 3d. The complicated series of operations necessary. 4th. The large amount of labor and fuel required. 5th. The production of noxious gases which necessitate extensive condensing arrangements. 6th. The large capital necessary for the erection and maintenance of the plant. These objections have long been recognized, and many attempts have been made during the last thirty or forty years, to discover and introduce a cheaper and more direct method for the manufacture of this important staple. The reaction between bicarbonate of ammonia and common salt, whereby bicarbonate of soda, insoluble in a solution of chloride of ammonium, is precipitated, has been closely studied for the last twenty-four years, on account of its simplicity and the purity of the product it affords. This ammonia-soda process is now so far developed, that while it is not .in position to entirely replace the Leblanc process, yet it can successfully compete with it where the conditions and localities are favorable. The advantages of the ammonia-soda process may be summed up as follows : 1st. It is independent of the essential agent in the Leblanc process, viz., sulphuric acid, and hence can be established in those localities where salt is abundant, and yet where sulphuric acid could not be made, or where it could not be transported profitably. 2d. The ammonia-soda process being a " wet" process, the evaporation of salt brines to obtain the solid salt required in the Leblanc process, is rendered unnecessary. 3d. The direct conversion of chloride of sodium into bicarbonate of soda, which can readily be converted into the maketable monocar-

Jan 1, 1879

By E. E. Malouf

With the continued development of low-grade porphyry copper deposits by open pit mining, substantial amounts of copper-bearing strip material have been accumulated in waste dumps adjacent to the many large mines. Since the end of World War II, the production of copper from leaching these copper-bearing wastes increased from approximately 4% of the total copper production to 10% by the early 1960's. Projected increases will probably raise this figure to 20 to 30% by the early 1970's. Furthermore, a gradual recognition of the economic feasibility of leaching mined-out areas is evident and will undoubtedly contribute additional production. Waste dumps in canyons and gulches on the periphery of open pit mines, mine stopes, caved areas, and abandoned open pits often contain substantial quantities of leachable rock ranging in concentration from 0.1 to 0.4% copper. Recent developments in the leaching of copper, mainly the recognition of bacterial oxidation of sulfide minerals combined with better under- standing of the control of the salt content of the leach solutions, both by adjusting the pH and/or by hydrolysis, are resulting in a greatly expanded recovery of copper from these hitherto uneconomic mine rejects. 11.5-1. Mechanism of Leaching. Leaching processes for the extraction of metal values from mine ore or waste may be classified for convenience as either chemical leaching or bacterial leaching. Chemical leaching is considered to be the extraction of soluble salts by metathesis in acidic, basic, or neutral water solutions. The reactions involved may be evaluated by chemical thermodynamics. Bacterial leaching, although a chemical process, is dependent on biological catalysis and this is generally a much more complex process. This justifies its separate treatment in the application to leaching. Acid ferric sulfate solutions are commonly employed in the mining industry to leach valuable metals from metal sulfide ores. The leaching mechanism is a reduction-oxidation reaction in which minerals are oxidized at the expense of ferric sulfate. Such chemical leaching is profitable when

Jan 1, 1968

By H. C. George

As the basis for a round table discussion of Petroleum Engineering Education for the February, 1930, meeting of the Petroleum Division, A. I. M. E., the following questions were sent to about 60 of the leading engineers and educators in the petroleum industry: 1. Should there be any changes in the curricula of our courses in petroleum engineering to meet the changing demands of the Industry? If so, what changes?] 2. Should courses in petroleum engineering be offered through university extension? 3. Should the universities offer correspondence courses in petroleum engineering? 4. What should be the character of the graduate work offered in petroleum production engineering? 5. Should summer work in the oil fields, on pipe lines, or in oil refineries be required of undergraduates? If so, how much and of what character? The following men replied to the questions: G. B. Corless, Humble Oil & Refining Co., Houston, Texas. J. R. McWilliams, Skelly Oil Co., Tulsa, Okla. W. W. Scott, Humble Oil & Refining Co., Houston, Texas. H. H. Power, Gypsy Oil Co., Tulsa, Okla. L. G. E. Bignell, Oil K. Gas Journal, Tulsa, Okla. E. L. Estabrook, Pan American Petroleum & Transport Co., New York, N. Y. F. P. Donohue, Pan American Petroleum & Transport Co., New York, N. Y. C. 0. Rison, lndian Territory Illuminating Oil Co., Bartlesville, Okla. L. B. Holland, Phillips Petroleum Co., Bartlesville, Okla. H. J. Kemler, Shell Petroleum Corpn., St. Louis, Mo. C. A. Bonine, Pennsylvania State College, State College, Pa. J. 0. Lewis, Dunn & Lewis, Tulsa, Okla. A. G. Heggem, Tulsa, Okla. J. M. Lovejoy, Petroleum Bond & Share Corpn., New York, N. Y. B. B. Boatright, Colorado School of Mines, Golden, Colo. A. C. Ruble, Union Oil Co. of California, Los Angeles, Calif. J. B. Umpleby, Goldelline Oil Corpn., Oklahoma City, Okla. R. S. Knappen, Gypsy Oil Co., Tulsa, Okla. K. C. Heald, Gulf Companies, Pittsburgh, Pa. K. C. Sclater, Exchange National Bank Bldg., Tulsa, Okla. F. G. Tickell, Stanford University, Stanford University, Calif.

Jan 1, 1930

By R. V. Norris

IT was stated in a former paper1 that an intensive study of anthracite costs was being made by the engineers of the United States Fuel Administration. The results of this-study are now available and are offered as a supplement to the former paper. Anthracite costs as reported, for the 6-months period, December, 1917, to May, 1918, inclusive, as compiled by the Federal Trade Commission, were used as a base, and charts similar to those described in the-former paper were made for the standard white ash anthracite and for red ash and Lykens valley coals. ADJUSTMENTS The adjustments of cost from a reported to a price-fixing basis, as described for the bituminous methods, were applied but showed only minor adjustments as necessary. The great spread in anthracite prices on the varying sizes, which for the 6-mo. period under review ranged in average from $5.244 for nut to $2.074 for barley coal, makes the question of the percentage of sizes produced at the different collieries a vital one. The realization with the same prices for each size must be within very wide limits, when it is considered that the percentage of prepared coal reported from different collieries varied from over 80 per cent. to below 30 per. cent. for fresh-mined coal. Hence, as the spread in prices for the various sizes must be predicated on some percentage, it is essential to find some method of adjustment to allow for this variation. The logical method of adjustment is to calculate actual costs to costs as of the standard percentage of sizes, so that the margin between the adjusted costs and the average realization shall be the actual margin for each colliery between its actual costs and actual realization clue to its particular percentage of sizes. As a base for realization the actual percentage of sizes for fresh-mined coal for the 6-mo. period was adopted. This percentage is given in Table 1.

Jan 2, 1919

By Hubert O. DeBeck

The following descriptions and explanations apply specifically to the use of the Hotchkiss Superdip, but there are no apparent reasons why they should not apply to any magnetometer. This paper is a product of work in the practical field for several years with the Hotchkiss magnetometer, mostly on mineral deposits in the southeastern United States. The paper describes the result of an attempt to develop a practical and economical field method that approaches, as nearly as possible, the utmost accuracy of which the magnetometer is capable. As there are many published descriptions of various magnetometers and magnetic methods, it would be superfluous to describe such instruments here, but a limited bibliography on the Hotchkiss and Askania magnetometers is appended. The Hotchkiss and the vertical Askania magnetometers have, respectively, maximum sensitivities of approximately 5 and 30 gamma per instrument scale division. Purpose of New Method The purpose of the method described in the following paragraphs is to eliminate, as far as possible, all corrections of field data that cause complexities and inaccuracies in the results of magnetometer surveys. Magnetometer field observations must be corrected for periodic variations in the intensity of the earth's magnetic field, as well as for temperature variations, both of which take place during the course of a day. These variations do not seriously handicap magnetometer work on highly magnetic deposits, but it is impossible to obtain accurate results, by the conventional methods in use today, over weakly magnetic or diamagnetic deposits. This is due to the physical inability to obtain by such methods sufficiently accurate data in the field to make dependable corrections. The magnitude of the necessary corrections of field observations frequently exceeds the magnitude of local magnetic anomalies obtained over various types of mineral deposits. Therefore if these corrections are neglected or made on the basis of inaccurate data, the entire magnetic picture of the area concerned is at least distorted, and perhaps destroyed altogethcr.

Jan 1, 1934

By P. D. Merica

IN connection with other investigations on the properties and characteristics of chilled iron car wheels, the question as to the best range of annealing temperatures was raised. Chilled-iron wheels are cast with a chill against the tread and the inside of the flange, the remainder being in sand. The composition of the metal is so chosen that under these conditions the tread and inside of the flange will show white iron to a depth of from 5/8 to 7/8 in. (15 to 22 mm.), the remainder of the wheel becoming graphitized or gray. In order to relieve the stresses set up during cooling under such drastic conditions, the wheels are stripped from the mold, while still red hot, piled in a soaking pit, and allowed to cool very slowly from their temperature at stripping. Obviously the most suitable temperature for this annealing is the highest at which no formation of graphite occurs within the white tread and at which the wheels can be stripped from the molds. Inasmuch as no direct determinations have been made of the temperatures at which the' formation, of graphite takes place in white iron of compositions used in car wheels upon annealing, it was considered worth while to determine these temperatures as a means of establishing the maximum temperatures at which the annealing of the wheels may be carried out. In the course of this work, some incidental observations were made which are of interest in connection with the theory of graphitization in white iron. The literature on the subject of the formation of graphite both during cooling at casting and upon annealing is very extensive and can be best studied by reference to a comprehensive discussion of the subject by Hatfield. 1 Perhaps the most important contributions of previous investigation are the following: 1. Whether a given mass of molten iron becomes white, mottled, or gray upon casting, depends on its composition and its rate of cooling through the temperature range of solidification and immediately below.

Jan 7, 1919

By R. E. Reed-Hill, J. L. Martin

Kinking is an important deformation phenomenon in poly crystalline a zirconium. The crjlstallo-gvaphic features of the most important form of kinking have been determined with the aid of twins formed at 77°K in grains previously kinked at high temperatures. It has been .found that the kink-band boundaries correspond to walls of edge dislocations with (1150) Burgers vectors and dislocation lines parallel to (1070). The present observations imply that basal slip is an important secondary-slip mode in polycrystalline zirconium. Previous single-crystal studies13 did not veveal this mode Other evidelzc.e for (0002)(1120) slip is also presented. ThE first studies of kinking in hexagonal metals were made by orowan,1 using single-crystal cadmium wires. He suggested that this was a new de- formation mode in metals, different from ordinary glide or twinning. Next, Hess and Barrett2 studied zinc-crystal rods in compression, and were able to offer an explanation of the phenomenon described by Orowan. They concluded that kinks required no new deformation mechanism and were a special form of deformation band that developed gradually and solely from basal glide. Similar kink bands were then observed by Washburn and parker3 on zinc crystals deformed in tension at low stresses and high temperatures. In titaniun,4 kink bands associated with {1010}<1120> prism slip have been observed in coarse-grained specimens. Magnesium5 and rhenium6 have also been observed to kink in conjunction with their basal- and {1010} prism-slip systems, respectively. Yttrium has (1010) as a predominant slip plane, but no observations of kink bands were reported.7 Since no previous investigations of kink bands in zirconium have apparently been made, this study was proposed. Its aim was to determine the crys-tallographic features of a type of kink band frequently observed in polycrystalline zirconium. EXPERIMENTAL APPARATUS All tests were performed on a type TTC Instron machine. The cross-head speed usually chosen in tension or compression was 0.02 in. per min. Ten-

Jan 1, 1964

By David J. Dunn

GENERAL NOTES Liner Design for Comminution Liners in crushers and mills are the mechanical link between machine and ore. The way liners transfer energy to media and ore determines to large degree the production rate, liner wear rate, maintenance cost, energy use, and availability of the comminution process. Plant capacity and mineral recovery economics, and return on investment, are thus strongly dependent upon these simple, low cost metal shapes of which so much is demanded. The complexity of dynamic relationships between liner configuration, material properties, ore characteristics, and operating parameters defy simplistic generalization. Rules-of-thumb and axioms of years past fall into disuse almost daily as new analytical methods, assisted by computers and sophisticated control systems, are applied to crushing and grinding processes. Recent literature is well supplied with references citing production benefits that improved liner designs produce. This chapter is intended to review especially promising liner designs and material developments and presents cameo case studies showing the benefits derived from their application to comminution circuits (Tables 1,2,4,5,7). Complete discussions of liner design and wear materials are beyond the scope of this chapter. Norman&apos;s comprehensive studies in references (1) and (2) and Mclvor&apos;s analyses of mill speed/configuration effects (3) are especially useful reading for designers and operators of crushing and grinding circuits. Changing trends in ore, product value, and costs of wear materials, interest, labor, and energy, make ongoing evolution of liner design equally important for existing mines and for projects still on the drafter&apos;s board. Original designs supplied as new equipment must, of necessity, be best estimates. These can usually be improved as operating experience replaces engineering forecasts. Advent of new materials or design concepts such as the Angular Spiral Liners (Korpi (4) ) or Norman&apos;s Bimetallic design (2) offer improvement potential that must be evaluated if a given circuit is to be kept competitive versus others making similar products.

Jan 1, 1982