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By C.P. Clingerman

The recent iastallation of a combination dust catcher, gas washer and precipitator at Carrie blast furnaces of the Homestead Steel Works has given very satisfactory results. The following description of the gas-cleaning installation is based on actual operating experience. When Carrie blast furnace No. 3 was rebuilt the decision was made to fine-clean all the gas produced by the furnace, because the management wanted fine-cleaned gas for fuel in the stoves and boilers. In order to keep the installation cost as low as possible, the gas-cleaning system was streamlined. All by-pass lines and goggle valves for bypass lines were eliminated from the system. A radical departure from the use of 8-in. tubes in the Cottrell-type precipitators was made by using 12-in. diameter tubes in a single compartment, the single compartment being divided into two units by a single partition wall in the top header. The Furnace Proper A few of the characteristic points and dimensions of the furnace proper are: Hearth diameter.............. 26 ft. o in. Bosh diameter............... 29 ft. 1 3/4 in. Stock-line diameter........... 20 ft. o in. Large-bell diameter........... 14 ft. 8 in. Small-bell diameter........... 6 ft. 6 in. Height of furnace from center of iron notch to bottom of large bell, closed............ 94 ft. 4 in. Height of furnace from center of iron notch to main platform ...................... 105 ft. o in. The furnace top is equipped with a MC-Kee revolving distributor, the operation of which is electrically interlocked with the skips, bell hoists, and coke-weighing and charging apparatus through a Freyn automatic charging control. The gas leaves the furnace first through four offtakes, 5 ft. 9 in. in diameter, then through uptakes that, are approximately 85 ft. high, which feed into a single down-comer that is 9 ft. in diameter. Dust Catcher The primary dust catcher installed (Fig. I) may be described as a single-cone type. The inlet pipe at the top of the dust catchei is 9 ft. in diameter; it is flared to a conical shape as it extends down inside the dust-catcher shell, which is 35 ft. in diameter, 37 ft. high on the straight side, and has a conical top and bottom. The slope of the bottom is so0 with the horizontal. The cone-shaped pipe inside the dust-catcher shell is 42 ft. high and is 19 ft. 7 in. in diameter at its bottom lip where it releases the gas inside the dust catcher. The ratio of the area of the inside cone at its bottom lip to the

Jan 1, 1943

By C. P. Clingerman

The recent iastallation of a combination dust catcher, gas washer and precipitator at Carrie blast furnaces of the Homestead Steel Works has given very satisfactory results. The following description of the gas-cleaning installation is based on actual operating experience. When Carrie blast furnace No. 3 was rebuilt the decision was made to fine-clean all the gas produced by the furnace, because the management wanted fine-cleaned gas for fuel in the stoves and boilers. In order to keep the installation cost as low as possible, the gas-cleaning system was streamlined. All by-pass lines and goggle valves for bypass lines were eliminated from the system. A radical departure from the use of 8-in. tubes in the Cottrell-type precipitators was made by using 12-in. diameter tubes in a single compartment, the single compartment being divided into two units by a single partition wall in the top header. The Furnace Proper A few of the characteristic points and dimensions of the furnace proper are: Hearth diameter.............. 26 ft. o in. Bosh diameter............... 29 ft. 1 3/4 in. Stock-line diameter........... 20 ft. o in. Large-bell diameter........... 14 ft. 8 in. Small-bell diameter........... 6 ft. 6 in. Height of furnace from center of iron notch to bottom of large bell, closed............ 94 ft. 4 in. Height of furnace from center of iron notch to main platform ...................... 105 ft. o in. The furnace top is equipped with a MC-Kee revolving distributor, the operation of which is electrically interlocked with the skips, bell hoists, and coke-weighing and charging apparatus through a Freyn automatic charging control. The gas leaves the furnace first through four offtakes, 5 ft. 9 in. in diameter, then through uptakes that, are approximately 85 ft. high, which feed into a single down-comer that is 9 ft. in diameter. Dust Catcher The primary dust catcher installed (Fig. I) may be described as a single-cone type. The inlet pipe at the top of the dust catchei is 9 ft. in diameter; it is flared to a conical shape as it extends down inside the dust-catcher shell, which is 35 ft. in diameter, 37 ft. high on the straight side, and has a conical top and bottom. The slope of the bottom is so0 with the horizontal. The cone-shaped pipe inside the dust-catcher shell is 42 ft. high and is 19 ft. 7 in. in diameter at its bottom lip where it releases the gas inside the dust catcher. The ratio of the area of the inside cone at its bottom lip to the

Jan 1, 1943

By C. J. Fleisch, C. P. Clingerman

THE recent installation of a combination dust catcher, gas washer and precipitator at Carrie blast furnaces of the Homestead Steel Works has given very satisfactory results. The following description of the gas-cleaning installation is based on actual operating experience. When Carrie blast furnace No. 3 was rebuilt the decision was made to fine-clean all the gas produced by the furnace, because the management wanted fine-cleaned gas for fuel in the stoves and boilers. In order to keep the installation cost as low as possible, the gas-cleaning system was streamlined. All by-pass lines and goggle valves for bypass lines were eliminated from the system. A radical departure from the use of 8-in. tubes in the Cottrell-type precipitators was made by using 12-in. diameter tubes in a single compartment, the single compartment being divided into two units by a single partition wall in the top header. THE FURNACE PROPER A few of the characteristic points and dimensions of the furnace proper are: [Hearth diameter 26 ft. o in. Bosh diameter 29 ft. 1 3/4 in. Stock-line diameter 20 ft. o in. Large-bell diameter 114 ft. 8 in. Small-bell diameter 6 ft. 6 in. Height of furnace from center of iron notch to bottom of large bell, closed 94 ft. 4 in. Height of furnace from center of iron notch to main platform 105 ft. o in.] The furnace top is equipped with a McKee revolving distributor, the operation of which is electrically interlocked with the skips, bell hoists, and coke-weighing and charging apparatus through a Freyn automatic charging control. The gas leaves the furnace first through four offtakes, 5 ft. g in. in diameter, then through uptakes that are approximately 85 ft. high, which feed into a single down-comer that is 9 ft. in diameter. DUST CATCHER The primary dust catcher installed (Fig. I) may be described as a single-cone type. The inlet pipe at the top of the dust catcher is g ft. in diameter; it is flared to a conical shape as it extends down inside the dust-catcher shell, which is 35 ft. in diameter, 37 ft. high on the straight side, and has a conical top and bottom. The slope of the bottom is 50° with the horizontal. The cone-shaped pipe inside the dust-catcher shell is 42 ft. high and is 19 ft. 7 in. in diameter at its bottom lip where it releases the gas in-

Jan 1, 1943

By I. C. Edwards, W. J. Dengler, D. F. Lillie

By 1959 the milling plant of Bicr oft Uranium Mines Ltd. had been in operation for two years. During this time many changes, both physical and chemical, had been made in an effort to improve plant efficiency. Investigational work had been facilitated greatly by the fact that the Bicroft mill consists to a large extent of two parallel circuits; however, the number of interrelated variables is great, and it is difficult to measure, let alone control, all of them simultaneously. The Bicroft mill staff feels that much progress has been made, but there is much yet to be done and many questions still to be answered. The Addendum outlines noteworthy developments to the fall of 1960. The property of Bicroft Uranium Mines is located in Cardiff Township in the Highlands of Haliburton County, southeastern Ontario, some 140 miles northeast of the city of Toronto and 70 miles due north of Lake Ontario. The ore-bearing dikes are classed as mafic. nonsegregated, syenite and granite pegmatite. Microline, microline perthite, quartz, sodic plagioclase, and pyroxene or biotite are the main constituents with uraninite, uranothorite, fluorite, titanite, cryolite, calcite, pyrite, pyrrhotite, and molybdenite as important accessories. The mill was designed for a nominal capacity of 1000 tpd with all sections except grinding, leaching, and clarification capable of 1500 tons. Feed was entered to one mill unit on Oct. 29, 1956, and to the second parallel line on November 13. The total feed rate was at 1000 tpd on November 15. The first precipitate was produced on November 12. By August 1958 the average entry had been increased to 1410 tpd without the installation of any additional major equipment. The overall recovery has been greater than 93.0 pct on several months, but a recovery of 92.5 pct appears to be most economical. Operating time for eight months in 1958 has been 97.1 pct although all grinding mills were relined during this period. A generalized flowsheet is shown in Fig. 1 and the plant layout in Fig. 2. The ore is crushed in three stages to -3/8-in. and then is wet ground in two stages to approximately 50 pct -200 mesh. The pulp is thickened to 68 pct solids and agitated by air for 33 hr at a pH of 1.9 as maintained by the addition of 93 pct sulfuric acid. Separation of the uranium-bearing pregnant liquor from the residue is accomplished by five-stage countercurrent decantation (CCD), following which the liquor is clarified for removal of fine slimes. The clarified liquor is treated in the ion exchange equipment in which both the upgrading of the solution and the removal of some impurities is accomplished. Addition of magnesia to the high-grade eluate from ion exchange precipitates the uranium as sodium-magnesium diuranate. After being filtered and dried this precipitate is packaged in drums for shipment. The residue from CCD and the barren solution from ion exchange are neutralized by the addition of lime and pumped to the tailings disposal area. CRUSHING All crushing is done on surface in a conventional three-stage unit consisting of a 36x48-in. Birdsboro Buchanan jaw crusher, a 4 1/4-ft standard Symons cone crusher, and a 4-ft Symons shorthead. Both the two primary and the two secondary screens are 4X 8-ft Symons rod decks. Moisture content of the feed ranges from 3 to 4 pct. In the initial installation the primary screens were equipped with 5/16-in. rods at 1 1/4-in. spacing and the secondaries with 5/16-in. rods at 1/2-in. spacing. With this arrangement the average crushing rate was better than 180 tph. To reduce the work required of the grinding circuit as tonnage was increased, several changes were made in the crushing circuit. By September 1957, both secondary screens had been reduced to 3/8-in. spacing, and rod size had been reduced to 3/16-in. to provide increased open area. Average throughput was reduced to 160 tph. Later, 50 pct of one primary screen was decreased to 1/2-in. opening to better balance the load between the two cone crushers. In May 1958,

Jan 1, 1961

By A. E. Zawadzki

A progress report is presented on the development of a process for the removal of sulfur dioxide from flue gases. Catalytic oxidation of the sulfur dioxide in flue gases, with the production of recoverable sulfuric acid, has been demonstrated to be technically feasible. Problems associated with the process are discussed. The need for an inexpensive and efficient process for controlling sulfur dioxide emissions from utility plant stacks has been accentuated by the ever-increasing public demand for elimination of all man-made air pollutants. I would like to describe the results of an investigation of the development of such a process; more important, I would like to present a discussion of the problems associated with the process which remain to be solved. The research work on the BCR catalytic gas phase oxidation process has been jointly sponsored by the Association of Edison Illuminating Cos., Edison Electric Inst. and Bituminous Coal Research, Inc., since 1958. However, work on SO2-pollution abatement was initiated by BCR in 1953. Tieman and Clymer,1 working with ozone and simulated flue gases, evaluated a gas phase oxidation process for removing SO2 from flue gases. Their experimental data indicated that the use of ozone to oxidize SO2 in flue gas concentrations, with subsequent recovery of H2SO4, did not appear to be economical due to the large ratio of ozone to sulfuric acid produced (2.6 to 1). The cost of the ozone would be 6 to 10 times the cost of sulfuric acid produced. As a result of the ozone study, work on a catalytic oxidation process was developed. The following reactions are the basis for the catalytic oxidation process Reaction [I] normally occurs in the combustion of sulfur-bearing fuels. At the high temperature found in the combustion chamber, 95% to 99% of the sulfur in the fuel is oxidized to SO2 and 1% to 5% is oxidized to SO3. The concentration of SO2 in the combustion gases depends on the combustion efficiency and the quantity of excess air used. A commonly used rule of thumb is 0.1 percent by volume SO2 in the flue gas for each 1% sulfur in the fuel. Reaction [2] proceeds at a wide range of temperatures. The rate of the reaction is rapid above l,000°F; however, the equilibrium conversion drops rapidly above this temperature. 2 Reaction [3] occurs rapidly to completion at temperatures below 400°F; above this temperature some SO3 exists in equilibrium with H2SO4. Complete dissociation of H2SO4 occurs above 650°F.3 The simplicity of the proposed process provided added incentive to the development and evaluation of the various component unit operations. The advantages of the process were considered to be as follows: 1) no raw materials were required, 2) the unit operations were not radically new; and 3) a salable product, sulfuric acid, would be produced. The successful development of the process was contingent upon the solution of several major problems: 1) The development of a catalyst which would provide high catalytic activity at reasonable conditions of gas flow and temperature without causing an unacceptable increase in pressure drop. 2) The development of a high temperature dust collection system to provide clean flue gases to the catalytic reactor. 3) The complete recovery of the sulfuric acid produced in the process; the effluent gas must contain less than 20 ppm by volume of sulfuric acid. As of this date, the complete solution to these problems has not been achieved. EXPERIMENTAL Catalyst Development: The use of platinum and vanadium catalysts for the production of sulfuric acid by the treatment of dry gases containing 5% to 20% by volume sulfur dioxide has been known for many years. The application of the basic idea of catalytic oxidation of sulfur dioxide in flue gas concentrations was

Jan 1, 1965

By Walter W. R. May

FOR more than 25 years a few business men who represent virile private enterprise in the Pacific Northwest have been trying to awaken the community to the potential benefits of an open Columbia River. No threat of government com- petition then hung over the industry, which was adjusted to state regulation. Numerous sites were engineered and the findings were laid before the operators of heavy industry in the East, Middle West, and South -even of Europe. These engineering data became, if not the basis, the inspiration upon which the U. S. Army Engineers eventually were to "build the Columbia River Bible" - their great document known as House Document 103, the report on the Columbia River and minor tributaries.

Jan 1, 1940

By Linney, Robert J.

REPUBLIC Steel Corporation's iron-ore properties in the Adirondacks consist of mines, mills, and sintering plants in the Mineville and Port Henry area and at Lyon Mountain. This article will deal with the properties in the vicinity of Mineville and Port Henry. In 1938, when Republic leased the Mineville- Port Henry operations from the Witherbee Sherman Corp., these properties had just come through some hard depression years. As a result, the mine development program was far behind schedule; most of the equipment needed replacement; and above all, the entire system of mining had to be completely changed to reduce operating costs. The concentrator had been in operation for many years; the process was dry and dusty. Machinery and equipment were either badly worn or entirely obsolete. The sintering plant, also long in operation, was badly in need of repairs.

Jan 1, 1943

By E. H. Crabtree

This paper traces the experimental and pilot plant work completed by the authors since 1939 including the various methods which have been developed in applying coarse activated carbon to cyanidation. The methods and results developed by the authors in desorbing gold and silver from carbons are given and the possibilities for the re-use of the desorbed carbons are discussed

Jan 1, 1950

By EDWARAD A. SIVEDENBORMG

REPORTS have been made at different times on the progress of water encroachment in the Frontier sands in the Salt. Creek oil field, Natrona county, Wyoming. All previous reports have, -however, been largely based on the position of water in the sands as determined by various physical tests. Subsequent information has been secured through a preliminary investigation of the porosity, grain size and degree of saturation of the Frontier sands. Also, a closer differentiation has been made between the waters encountered incident to the production of oil by means of chemical analysis. In view of the more recent developments there has been a need of a water encroachment map of the first Wall Creek based on a field survey and additional information acquired since the water encroachment map of the sand of 1926, by J. S. Ross and E. W. Henderson, petroleum engineers of the U. S. Geological Survey. The present report is confined to a study of the first Wall Creek sand and was written in connection with the preparation of the map, showing water encroachment in this sand. The first Wall Creek sand was the discovery sand in the field, the first well having been drilled in 1908. Its thickness averages 120 ft. and, varies between 90 and 160 ft. The sand is in the Colorado group of the Upper Cretaceous series and is further considered as a part of the Frontier formation found in other parts of Wyoming.

Jan 1, 1930

Jan 1, 1888

THOSE NOT MARKED ARE MEMBERS; MARKED THUS ? ARE ASSOCIATES. HEAVY-FACED TYPE SIGNIFIES HONORARY MEMBERSHIP. JUNIOR ASSOCIATES ARE MARKED II. THE FIGURES AT THE END OF THE ADDRESS INDICATE THE YEAR OF ELECTION. ?AARONSON, ALFRED E Pres., Tuloma Oil Co., Unity Bldg., Tulsa, Okla. '18 ABADIE, EMILE R., Min. Engr Box 291, Porterville, Tulare Co., Cal. '76 ABBOTT, CLARENCE E., Gen'l Supt., Iron Mines Div., Tenn. Coal, Iron & R. R. Co. 1405 Minnesota Ave., Bessemer, Ala. '04 ABBOTT, LOUIS BENJAMIN, Chief Engr., Consolidation Coal Co., Elkhorn Div. Jenkins, Ky. 115 ABBOTT, ROBERT R. Met. Engr., Peerless Motor Car Co., Cleveland, Ohio. '12 ABE, ASAKA Fujitagumi Taiwan Office, Taipeh Formosa, Japan. '14 ABEEL, GEORGE H., JR., Cons. Min. Engr., 4111 Lafayette Ave., St. Louis, Mo. '18 ABEY, HIROSHI, Min. & Met. Engr., Arakawa Mine, Mitsubishi Co., Senpoku-gun, Akitaken, Japan. '17 ||ABOUCHAR, S. S., Cia. de Minerales y Metales, S. A. Santa Eulalia Unit, Apt. 70, Chihuahua, Chih., Mexico. '17 ABRAHAMS, A. I 1391 Madison Ave., New York N. Y. '14 ?ACKER, E. O'C., Met., 128 East Washington Lane, Germatown Philadelphia, Pa. '86 ACKER, WILLIAM L., Diamond Drill Contractor... Mears Bldg., Scranton, Pa. '18 ?ACKERMAN, ERNEST R., Pres., Lawrence Portland Cement Co. Plainfield, anion Co.. N. J. '15

Jan 1, 1923

By Louise Reber

THE town of Jerome is located in Yavapai County in north central Arizona. It has a population of over 6000 people and the two important mines of the district, the United Verde and the United Verde Extension, lie almost within its limits. Perched high on the southwest side of the Verde Valley, at elevations of 4800 and 5500 ft.. (1463 and 1676 m.), both mines have long tunnels from their lower levels through which ore is hauled to their respective smelters. The two smelter towns of Clarkdale and Verde, out in. the center of the valley and about 2000 ft. (609 m.) below, form part of the wide panorama that meets the eye at Jerome. This panorama and the topographic and surface features and the geologic formations are shown in a separate pamphlet. In the vicinity of Jerome, the great southern escarpment of the Arizona plateau forms the northeast side of the Verde valley. The general level of this escarpment, or "the rim" as it is called, is about 4000 ft. above the Verde River. A corresponding elevation is reached only by the, highest parts of the Black Hills, which bound the valley to the southwest. The two lava-capped mesas, known as Mingus and Woodschute Mountains, form the culmination of the Black Hills. That part of the old Black Hills mining district which lies between their crests -and the Verde River is now known as the Jerome or Verde copper district. However, if the smelters are not included, a strip about 7 mi. long and 3 mi. wide (11 by 5 km.) embraces practically all the properties belonging to the Jerome district. This strip lies parallel to and along the side of the Verde valley from about First View, 2 mi. northwest of Jerome, to the neighborhood of Allen Spring, near the south end of Mingus. Mountain. The rank of the district in copper production, as well as features of peculiar geologic interest in connection with the ore occurrences, entitle the district to much more consideration than it has received in the literature of copper mining. Arizona stands preeminent as a copper-producing state. In 1918, it produced four-tenths of the total amount produced in the United States, and nearly equaled the, combined production of its three chief competitors, Montana, Michigan, and Utah. The production of the Jerome district places it in the sixth place among the copper

Jan 8, 1920

[A Aall, Christian H., M49 A Dir, Smelt & Ref, Am. Metal Climax, Inc., 1270 Ave. of the Americas, New York 20, N. Y. Aaroe, S. L., A54 A VP, W. S. Tyler Co. of Canada Ltd., P. O. Box 100, St. Catharines, Ont., Canada Abalos, Teodulo Q., J57 A Prod Frmn, Lepanto Cons. Mining Co., Lepanto, Mt. Province, Philippines Abbitt, James M., A54 770 Sole Blvd., Bartow, Fla. Abdullah, M. Y., J53 Dept. of Mines Res. Div., P. O. Box 1016 Tiger Lane,-Ipoh Peram, Malaya Abel, John F., Jr., J53 F Mine Engr, Thompson Creek Coal & Coke, Carbondale, Colo. Abell, Leo M., M31 B Const Supt, Phelps Dodge Corp., Morenci, Ariz. Abendroth, H. E., A57 Mangore Australia Pty. Ltd., 901 Hay St., Perth, W. Aust.,, Australia Abenius, Hakan V., M52 Falun, Sweden]

Jan 1, 1961

JAmes E. Howard, Watertown, Mass.:—In connection with this paper, it is the desire of the Watertown laboratory to receive suggestions as to the lines of work and the particular direction along which the examination of the ingot-metal should proceed, and any suggestions so offered will be noted with care, and the tests conducted so as to embrace such features as it is thought desirable to have investigated. To me the question of structural continuity seems of para-

Jan 1, 1909

By I. R. Kramer, L. J. Demer

Aluminum single crystals were pulled in an electrolytic cell allowing surface removal during the deformation. The extent of Stages I and 11 of the stress-st-aitz curve was increased and the slope decreased as the rate of metal removed from the surface was increased. An increase of the strain rate caused a decrease in the effectiveness of the metal removal. The data indicate that the work-hardening coefficient in Stage I is determined primarily by the conditions which exist on the surface of the crystal. In Stages 11 and 111, both surface effects and internal barriers are important. ALTHOUGH numerous investigations have been conducted on the plastic flow characteristics of metals in an attempt to explain the mechanism of work-hardening, relatively few studies have taken into account the influence of the surface. In all current theories of work-hardening it is assumed that the impediments to the movement of dislocations are within the crystal. The barriers due to the surface and the existence of solid and liquid films have been neglected even though it has been demonstrated that the surface exerts a large effect. A number of investigators1-l8 have shown that solid films on the surface of single crystals markedly affect their mechanical behavior. In general, the presence of a solid film tends to increase the yield stress and increase the work-hardening rate. Often, on single crystals, Stage I and, at times, Stage II regions are completely suppressed. Various mechanisms have been offered for the effects of oxide and metal films as well as the influence of electrolytes. Of these, concepts concerned with the locking of surface dislocation sources and the blocking of dislocations at the surface resulting in pileups appear to be actively considered at present. Barrett,11 Takamura,6 Gilman,19 Lipsett and King,20 Shapiro and Read,10 and Weiner and Gensamer21 are among those who have interpreted their results in terms of piled-up dislocations at the surface, while Adams.22 and Chalmers and Davis23 have explained their experimental observations in terms of locking of surface dislocation sources. In general, the change in plastic flow properties due to electrolytes has been explained in terms of the unblocking or unlocking of dislocations by the removal of the oxide films. In considering the two proposed mechanisms, it appears that the locking of sources of surface dislocations by a solid film should exert a primary influence only on the critical resolved shear stress for flow and not on the slopes of Stages I and 11. However, the blocking at the surface of dislocations from internal sources may also affect the critical resolved stress and furthermore exert an influence throughout the whole plastic range. In certain cases it does not seem feasible to explain the results of experimental observations in terms of locking of surface dislocation sources. The abnormal aftereffects found by Barrettll,12 by removing the oxide by an acid treatment are excellent evidence of the blocking of dislocations at the surface. Additional evidence in favor of a blocking due to a pileup of dislocations at the surface may be found from the observations that the critical resolved shear strength continues to increase with the thickness of the oxide layer until very heavy oxide layers are formed. If the locking of surface dislocations sources were the dominant factor, the critical resolved shear stress would not be expected to increase after all of the surface sources were locked by the formation of the oxide. This may be expected to happen after a few atomic layers of the oxide are formed. In spite of the above evidence on the strong influence of the surface on the plastic flow characteristic, this has been ignored in current theories of work-hardening. Seeger24,25 suggested that most of the dislocations may slip out of the crystal only when the specimen axis is within certain areas of the orientation triangle. In other areas the resolved shear stress in other glide systems is large enough to generate dislocations which can form Lomer-Cottrell locks, thereby decreasing the average slip distance in some directions and causing a larger hardening rate. Friede126 assumed that at the beginning of Stage 11, a large number of Lomer-Cottrell dislocations are formed by a catastrophic process which used up all the Frank-Read sources on the secondary slip-planes. In this manner a fixed number of Lomer-Cottrell locks is formed which act as barriers against which the dislocations can pile up. In Stage 111, Seeger24 and Diehl, Mader, and Seeger25 proposed that Lomer-Cottrell barriers are circumvented by the cross slip of extended screw dislocations. Cottrell and Stokes,27 Friedel,26 Cottrell,26 and stroh29 suggest that the Lomer-Cottrell dislocations collapse under the stress field of the dislocation pileup. It is the purpose of this paper to report the changes in Stages I, II,and III of the deformation process in

Jan 1, 1962

By Edward L. Beutner, Robert M. Crump

Benson Mines low-grade iron ore reserve is a replacement deposit within the Grenville gneisses of the Adirondacks. The average grade of the crude ore is about 23 per cent iron. The iron minerals are principally magnetite and hematite disseminated throughout the gneisses as discrete grains about 1 mm in size. Both the ores that are beneficiated by magnetic means and the non-magnetic ores that are treated by a gravity method of concentration are found in stratigraphically different positions but are mined from one open pit, which is about 2.5 miles long and 800 feet wide and are treated separately. The gneisses are described and named according to the distinctive mineralogy of each. Recognition of the gneissic types permits the interpretation of the structure as a northward-plunging syncline overturned to the west. A large subsidiary anticline-syncline complex occurs on the east limb of the major syncline. Iron minerals in sufficient quantity to be considered ore are confined to areas where the footwall rock has been overturned to become the hanging wall.

Jan 1, 1968

By D. H. Gieskieng

THE advent of curved jaw crusher wearing plates made an approach other than segmental layout analysis desirable for prediction of capacities. For some time it had been known that the drawing board capacities of crushers using these plates had to be considerably modified by complicated experience factors to achieve agreement with results. Because these apparent capacities could be readily increased severalfold by minor crushing chamber shape changes, it was necessary that the utmost precaution be taken in predicting capacities of jaw plates modified for nonchoking, special wear characteristics, or any other reason. To this end the laboratory and field tests outlined by the author in a previous paper1 were made on Blake-type jaw crushers. The results of these tests were summarized in a simple first degree equation applicable to crushers using either straight or curved jaw plates. This equation first outlines the maximum capacity potential of a given crusher, then reduces this figure in accordance with installation circumstances by means of a realization factor. It was found subsequently that this equation, with the addition of an eccentric throw factor, is applicable to standard types of single-toggle or overhead eccentric jaw crushers as far as maximum capacity potential is concerned. However, these crushers have realization factor curves somewhat different from those outlined for the Blake type. While this paper is concerned principally with standard type single-toggle crusher capacities, the evaluation of data obtained with these machines is simplified by comparative reduction to the 10 x 7 in. Blake-type equivalents upon which the summary of the preceding paper was made. Convertibility of data from one type of crusher to the other also tends towards confirmation of both. The agreement of these data is sufficient to be considered complimentary. Consequently the feed factors, f, previously reported for Blake crushers are slightly adjusted to an average with the single-toggle crusher results. Blake-type equation: C = f.d.w.y.t.n.a.r [I] Single-toggle type equation: C = f.d.w.y.t.n.a.e.r [21 where C is the capacity in short tons per hour through the crusher, f is a feed factor, dependent upon the presence of fines in the feed, and the surface character of the jaw plates used. Values of f : Smooth Plates Corrugated Plates With normal fines 0.0000414 0.0000319 Fines scalped out 0.0000368 0.0000252 Large pieces only . 0.0000312 0.0000215 d is the apparent density of the broken product in pounds per cubic foot. (If the true specific gravity of the feed is known, 40 pct voids may be assumed and d becomes 37.4 times sp gr). w is the width of crushing chamber in inches. y is the openside setting of the crusher, in inches. In the case of corrugated jaw plates it is measured from the tip of one corrugation to the bottom of the valley opposite. t is the length of jaw stroke in inches at the bottom of the crushing chamber. It is the difference between open and close-side settings. n is rpm, or crushing cycles per minute, a is the nip-angle factor. It is unity for 26" and 3 pct greater for each less nip-angle degree. A nip-angle of 20" has an a value of 1.18, and an angle of 30" has an a value of 0.88, see Fig. 1. r is the realization factor. It is unity for perfectly uniform choke feeding and usually less for actual operating conditions according to the method of feeding used and the probabilities of hang-ups involving the size of feed and crusher opening. Approximate values are given by the curves in Fig. 2. These values are further reduced by intermittent feeding, e is the throw or diameter of gyration of the single-toggle crusher eccentric in inches. As evident in Fig. 1A, variation of feed size will generally have little effect on nip-angle if both jaw plates have flat areas. Jaw plates having continuous curvature, as in Fig. 1B will have different nip-angles, depending upon the size of feed. For test work as described in this paper this effect was accounted. For general compilation of capacities for average feeds it is suggested that the nip-angle be taken at the various settings computed, at an arbitrary level, such as is indicated in Fig. 1C. Data Evaluation To bring the Blake and single-toggle type crusher capacity test results to common terms for evaluation, all data are converted to terms of 10 x 7 in. Blake-type performance at conditions of 100 lb per cu ft, 10 in. chamber width, 250 rpm, 0.65 in. stroke, 3-in. openside setting, and 18° nip-angle. (The nip-angle of the 10x7 in. Blake is 18° at 3-in. setting.) The single-toggle crusher performances are also divided by the eccentric throw to bring this effect to unity. As outlined,' laboratory and field tests made on Blake-type crushers ranging from 10 x 7 in. to 60 x 48 in. were summarized along the foregoing conditions of speed, stroke, etc. This resulted in groups of data which correspond to feeds with fines, feeds

Jan 1, 1952

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 A. B. Kinzel

ALTHOUGH the iron-carbon diagram has undergone many changes in the last 20 years, the region below the eutectoid line and up to approxi-mately 1.7 per cent carbon has been little affected. This region is generally considered to consist of cementite and ferrite. Graphite has been noted occasionally in the hypereutectoid steel region, and the ready formation of graphite nodules in malleable cast iron is a phenomenon difficult to interpret in the light of cementite, supposedly stable at sub-eutectoid temperatures. In this case the graphite formation has been partly explained by the presence of silicon, and many have believed that silicon acts to change the stable state rather than to accelerate reactions so as to arrive at the stable state in a briefer period of time. Consider-ation of this phenomenon indicates that cementite is not the stable phase in the temperature composition zone referred to. In the course of examining a low-carbon steel tube taken from a petroleum cracking still, which had been in service for approximately three years at temperatures somewhat below the eutectoid temperature, observations were made that shed light on this entire subject. The tube in question analyzed:1 C, 0.15 per cent; Mn, 0.49; Si, 0.02; S, 0.023; P, 0.015. The microstructure of the tube after service is shown in Figs. 1 and 2. From these it is evident that cementite as such is absent, and that in its place nodular graphite has been formed. In order to check this observation further, samples taken from the tube were heated at 850° C. for varying periods of time. The small samples were put into a large hot furnace, and the total time is recorded. The structure of the

Jan 1, 1934

By George J. Young

(San Francisco meeting, October, 1911.) THE nature of slimes handled in the treatment of gold- and silver-ores has been discussed in technical literature to a considerable extent. The subject of slime-filtration from the practical worker's stand-point has also received much comment, and scattered through the literature of the subject are descriptions of many slime-filtration installations. Articles of this nature serve a valuable purpose and assist materially in the design of new and the improvement of old plants. The subject of the physics of slime-filtration has been touched upon to only a slight extent. The underlying principles are worthy of more intensive study and experimentation than they have received, and the main purpose of this paper is to present the results of such study and experimental work as will serve to make clear in part at least many of the principles which control the filtration of slime. Nature of Slime. Much has bean written concerning an accurate definition of the term ? slime," but no comprehensive definition seems to be generally accepted. The reason for this is clear. A slime consists of at least three different substances, each, when separated, possessing distinctly different physical and to a certain extent chemical properties. These substances are extremely fine sand, a colloidal material which may be and generally is in a coagulated condition, and a colloidal material which is in a non-coagulated condition. Suspending a slime in a relatively large volume of water by shaking and allowing sedimentation to take place, results in the fine sand settling out with comparative rapidity, followed by the coagulated material, which settles much more slowly and finally a certain portion remains

Nov 1, 1911