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By S. Terry, J. G. Munro

A unique feature of the recently dedicated pelletizing complex of Hamersley Iron Pty. Ltd. is the dry grinding circuit for the iron ore fines. This facility, located at Dampier, some 800 miles north of Perth, Western Australia, has a rated annual capacity of 2 million tpy of iron ore pellets. The Mt. Tom Price orebody, which supplies the pelletizing plant, is a massive deposit of high-grade hematite containing an estimated 500 million tons of ore averaging 64% iron. The main impurities are ferruginous shales that occur in bands of varying widths in the orebody. An average analysis shows 4.4% SiO2, 2.0% A12O3, 0.05% P and 1.8% LOI.

Jan 5, 1968

By William Kent

During the discussions at the Philadelphia meeting in February last;) several speakers expressed their doubts of the general accuracy of chemical analyses of steel made by "iron works chemists," and especially of determinations of manganese. Since the meeting, the discussion of the " practical value of chemical analyses" has been continued at some length in 'the columns of the Iron Age.

Jan 1, 1882

By William Kent

DURING the discussions at the Philadelphia meeting in February last, † several speakers expressed their doubts of the general accuracy of chemical analyses of steel made by "iron works chemists," and especially of determinations of manganese. Since the meeting,. the discussion of the "practical value of chemical analyses" has been continued at some length in the columns of the Iron Age. †Transactions, vol. ix, p. 529.

Jan 1, 1882

By D. M. Francois-Bongarcon

The idea of parameterizing reserves has only been formalized and scientifically applied for a few years. Its most fully developed application, that of open pits, has been operational only since 1976. Two new versions which have just been issued provide a complete solution to the problem and also a powerful tool for mine planning, and they open up a new field of investigation. This paper describes the basic principles for parameterizing reserves, their application for open-pit mines, the algorithm used, the physical interpretation of the results obtained, their economic use as well as the first prospects offered by a complete parameterization in tm of (I. ti), or of the metal price.

Jan 1, 1984

By D. R. Franklin, L. L. Lien, C. W. Hoffman

The initial operation of a mining facility is a unique and often underplanned phase of the Project development process. The subject of this presentation is a detailed strategy to effectively and efficiently bring a mining facility to design production capacity. This plan has been applied successfully on projects. It addresses developing the initial operation organization, management of information and problem, putting an appropriate management system in place, developing operations and maintenance information, and effectively training personnel.

Jan 1, 1983

By K. P. Stricker, H. Keddeinis, K. Grebe

Recent investigations by Mannesmann Research have shown that disintegration of sinter with widely varying quality levels is subject to a much more complex set of influences than was previously assumed. It was confirmed that disintegration at temperatures between 300° and 600°C (570°and 1,110°F) is triggered by the degradation of hematite. The specific tendency of hematite to disintegrate is, however, not constant: sinters containing the same amount of hematite can show widely differing disintegration tendencies, depending on structural homogeneity, porosity, and gangue quantity. Sinters with heterogeneous structures transmit stress to the hematite phase and this favors disintegration. Another factor is the brittleness of the glassy silicate phase, which can be influenced even by small modifications of minor gangue constituents.

Jan 1, 1984

By F. E. Buch

The smelter is designed for a production capacity of 10,000 short tons of blister copper per month, when operating on the present concentrate grade. The :smelter lay-out is shown in Fig I. The major units of equipment comprise two reverberatory furnaces, three 13 by 30 ft Peirce-Smith converters, two straight line casting machines, one being served by a 13 by 30 ft holding furnace and the other by a ladle tilting quadrant, two converter aisle cranes and two converter blowers. The plant is compact and the general arrangement of standard gauge railway tracks and conveyor belts provides for a smooth flow of incoming materials and metallurgical products. Concentrate is received by conveyor belts and fluxes in standard railway trucks. The local track system is covered by an electric trolley locomotive. The Smelter treats a wet (10 pet moisture) flotation concentrate containing approximately 53 pct total copper and 0.9 pet oxide copper. The predominating minerals are chalco-cite, chalcopyrite and bornite accompanied by small quantities of malachite and cuprite. The gangue is highly siliceous and requires limerock as a flux. Metallurgy would be straightforward were it not for the necessity for eliminating bismuth which occurs as an impurity in the ore along with the copper. Directly or indirectly most of the Smelter problems can be traced to the necessity for bismuth removal. Copper recovery, based on new copper treated, averages 97.5 pct. General Description Flotation concentrate, containing 10 Pet moisture, is conveyed from the filter plant to the smelter storage bins by conveyor belts, the material being weighed in transit by a revolving drum type of weigh-hopper manufactured by Samuel Denison and Son, Ltd. The weigher consists of a steel drum with dished ends carried on a horizontal shaft and rotated by an 8 hp squirrel-cage motor through a worm and Spur reduction gear. A feed mouth in the drum permits of filling and discharging. The whole unit is supported on a framework resting on weighing levers, which in turn connect to transfer levers, thence to an indicator of the steelyard type situated 16 ft from the centre line of the drum. The indicator is of the "Denison" patent equilibrium controlled ticket stamping type, insuring mistake-proof records by a combination of electrical and mechanical movements which Prevent the operator from printing until the cover enclosing the steelyard is closed and until the poise-weights have been Set correctly to the weight of the hopper and contents. The machine is capable of weighing 30 short tons at a time but the usual load is 28 tons. After obtaining the gross weight the drum is rotated and discharged into a receiving bin situated below it. The empty drum is weighed and the net weight re-

Jan 1, 1949

By S. A. Mersol, C. T. Lynch, F. W. Vahldiek

The room-temperature Knoop hardness of single -crystal titanium diboride has been determined. Variations in microhardness have been correlated with orientation and structural imperfections in the crystals. Maximum differences in hardness values of 750 kg per sq mm with respect to orientation and 450 kg per sq mm with respect to substructure were found. The effects of etchants, load on indenter, and degvee of cracking of indentation were studied. The average hardness was determined as 2800 kg per sq mm on the as-grown crystals. Annealing increased the average hardness to 3375 kg per sq mm. ThE microhardness of polycrystalline titanium diboride approximating the stoichiometric composition TiB, has been studied by several investigators. The values for the Knoop hardness number range from 2710 kg per sq mm (Khn = 2710 kg per sq mm) to 3400 kg per sq mm.'-4 Samsonov et al.' reported a Vickers hardness number of 3400 kg per sq mm (Vhn = 3400 kg per sq mm) at 120-g loads for a 98 pct Ti + B material of 96 pct theoretical density. Recently Dunegan measured the Vickers hardness and obtained 2060 kg per sq mm with a 10-g load (Vhnlo = 2060 kg per sq mm), 1425 kg per sq mm for Vhnloo, and 1320 kg per sq mm for Vhnlooo. We have obtained a Khnloo = 3000 * 350 kg per sq mm for hot-pressed polycrystalline TiB2 that was 99.1 pct Ti + B and 96.6 pct of theoretical density. The present investigation has been made on single-crystal titanium diboride boules, and is believed to be the first such study on TiB, crystals of known orientation. EXPERIMENTAL The single crystals were prepared by a Verneuil-type process using an electric arc by the Linde Division of Union Carbide Corp. The largest specimens were 6 mm in diameter by 12 mm long. The crystals were of theoretical density (4.50 g per cm3) with a Ti + B content of 99.8 pct. The major impurities present were: 0.03 pct (by weight) 0, 0.06 pct C, 0.01 pct Si, 0.05 pct Fe, 0.01 pct Cr, and 0.01 pct Ni. The crystals were boron-rich, the average boron content being 31.S7 wt pct (stoichiometric value is 31.12 wt pct), and titanium-poor, the average titanium content being 68.2 wt pct (stoichiometric value is 68.88 wt pct). Titanium was determined gravimetrically by cupferron precipitation and boron by titration of H3B03 from a NaOH-fused specimen after removal of titanium with BaC03. The outer edge of the boule accounted for some of the excess boron. An electron-microprobe analysis showed that the titanium content increased from 60.0 wt pct at the edge to 68.5 wt pct at D, ~ 1000 p, where D, = distance from outer edge (see Fig. 5). X-ray measurements indicate that the boules are single crystals with considerable substructure. Upon etching this structure is seen in the form of a Widmanstatten-type rhombohedral line pattern in the basal (c) plane and a parallel "lines" pattern in the prism (a) planes. A typical WidmanstHtten-type pattern is seen in in Fig. 1. Electron microscopy reveals that the lines are less than 1 p across, which does not allow direct electron probe or microfocus X-ray determination of their composition. The identity of the second phase has not been established. It might be a higher boride or a nonstoichiometric TiB2. On annealing above 2200°C the precipitate is dispersed and dissolves in the matrix. The best etchants found were HF/HNO/HO, KF(CN)$NOH/HO (Murakami's Etch), and A large number of other etchants were previously Studied. The acidic etchant produced an acicular or "needles" pattern in the (a) planes which is an etchant effect on the "lines" pattern.

Jan 1, 1965

By E. S. Davenport, R. J. Hafsten, R. A. Grange

The influence of austenite grain size upon the hardenability of steel is now fairly well understood; for a given austenite, increasing the grain size increases the depth of hardening, and, since the latter is related to the fundamental transformation behavior of austenite, it follows that austenite decomposition must, in general, be retarded by increasing grain size. To date, very little quantitative information bearing directly on the effect of austenite grain size upon the progress and result of isothermal transformation has been published. Davenport and Bain,' and Zimmerman, Aborn and Bain2 have shown that the transformation is definitely relarded in hypereutectoid plain carbon steels at temperatures near and above the upper region of rapid transformation (Ar') when the austenite grains are increased in size. More recently, Griffiths. Pfeil and Allen3 investigated the effect of a series of different heating (austenitizing) temperatures upon the progress of isothermal transformation at 1245°F. (675°C.) and 745ºF. (395°C.) in a medium carbon, low-alloy steel; while they reported no measurements of the austenite grain size, their results suggest that increase in grain size retards austenite transformation at 1245ºF. (675°C), but has no appreciable effect at 745°F (395°C.). The present paper deals with the results of a study of the isothermal transformation of austenite in a single commercial alloy steel in which a fine-grained or a coarsegrained state was induced by appropriate selection of austenitizing temperature. The data are presented in the form of isothermal transformation diagrams, which clearly show that coarsening the grains lessens the rate of transformation of austenite to proeutectoid ferrite and pearlite—that is, at temperature levels above about 1000°F. (540°C.)—but is without significant effect at lower temperatures where the transformation product is bainite or martensite. It is to he presumed that the foregoing statement would be valid, at least in principle, for many other grades of steel; it confirms again that the mechanism of transformation to a pearlitic structure is fundamentally different from that to an acicular structure. A number of related observations were made, which seem to throw some light on the transformation process as it takes place in alloy steels, particularly at temperature levels in the vicinity of 1000ºF. (540°C.), where the transition from lamellar to acicular structures occurs. These data are discussed briefly in the belief that they may lead to a clearer understanding of this aspect of the subject. Material and Experimental Procedure The material investigated was a cornmercial grade of S.A.E. 4140 steel, the composition of which was as follows: 0.37 per cent C, 0.77 per cent Mn, 0.98 per cent Cr and 0.21 per cent Mo. It was hot-rolled to a 1 1/8-in. round bar and normalized by air-cooling from 1800°F. (980°C.).

Jan 1, 1941

By R. J. Hafsten, E. S. Davenport, R. A. Grange

The influence of austenite grain size upon the hardenability of steel is now fairly well understood; for a given austenite, increasing the grain size increases the depth of hardening, and, since the latter is related to the fundamental transformation behavior of austenite, it follows that austenite decomposition must, in general, be retarded by increasing grain size. To date, very little quantitative information bearing directly on the effect of austenite grain size upon the progress and result of isothermal transformation has been published. Davenport and Bain,' and Zimmerman, Aborn and Bain2 have shown that the transformation is definitely relarded in hypereutectoid plain carbon steels at temperatures near and above the upper region of rapid transformation (Ar') when the austenite grains are increased in size. More recently, Griffiths. Pfeil and Allen3 investigated the effect of a series of different heating (austenitizing) temperatures upon the progress of isothermal transformation at 1245°F. (675°C.) and 745ºF. (395°C.) in a medium carbon, low-alloy steel; while they reported no measurements of the austenite grain size, their results suggest that increase in grain size retards austenite transformation at 1245ºF. (675°C), but has no appreciable effect at 745°F (395°C.). The present paper deals with the results of a study of the isothermal transformation of austenite in a single commercial alloy steel in which a fine-grained or a coarsegrained state was induced by appropriate selection of austenitizing temperature. The data are presented in the form of isothermal transformation diagrams, which clearly show that coarsening the grains lessens the rate of transformation of austenite to proeutectoid ferrite and pearlite—that is, at temperature levels above about 1000°F. (540°C.)—but is without significant effect at lower temperatures where the transformation product is bainite or martensite. It is to he presumed that the foregoing statement would be valid, at least in principle, for many other grades of steel; it confirms again that the mechanism of transformation to a pearlitic structure is fundamentally different from that to an acicular structure. A number of related observations were made, which seem to throw some light on the transformation process as it takes place in alloy steels, particularly at temperature levels in the vicinity of 1000ºF. (540°C.), where the transition from lamellar to acicular structures occurs. These data are discussed briefly in the belief that they may lead to a clearer understanding of this aspect of the subject. Material and Experimental Procedure The material investigated was a cornmercial grade of S.A.E. 4140 steel, the composition of which was as follows: 0.37 per cent C, 0.77 per cent Mn, 0.98 per cent Cr and 0.21 per cent Mo. It was hot-rolled to a 1 1/8-in. round bar and normalized by air-cooling from 1800°F. (980°C.).

Jan 1, 1941

Vermont State Geological Survey, Burlington, Vt. G H. Perkins, State Geologist Most of the file reports of the State Geologist of Vermont were destroyed in a flood at Montpelier two or three years ago Full sets of 17 volumes may be seen only in libraries. The Annual Report for 1928 and the Annual Report for 1930 may still be had, as well as a few copies for the following years: 1901-2, 1907-8, 1909-10, 1915-16, 1921-22, 1923-24. These are distributed without charge. Flood-damaged copies of the two vols, Geology of Vermont, by Hager and Hitchcock, cost $3 plus postage For any of these volumes address State Librarian, Montpelier, Vermont.

Jan 1, 1933

Sept. 3-6, AIMS, Fall Meeting, Industrial Minerals, Minerals Beneficiation, Mining, Geology, & Geophysics, Iron and Steel, and Coal Div., Palmer House, Chicago. Sept. 3-13, AIMS, Chicago Section, Centennial of Engineering, Chicago. Sept. 5-6, Engineers' Connell for Professional Development, annual meeting, Hotel Sheraton, Chicago. Sept. 8-15, International Geologic Congress, Algiers. Sept. 11-13, American Institute of Chemical Engineers, Palmer House, Chicago, Ill. Sept. 18, RIME, Utah Section, Newhouse Hotel, Salt Lake City. Sept. 22-25, American Mining Congress, Metal and Nonmetallic Mining Convention and Exposition, public auditorium, Denver. Sept. 23-25, Institution of Mining and Metallurgy, symposium on mineral dressing, Royal School of Mines, London. Sept. 30, AIME, Morenci Sub-section, Longfellow Inn, Morenci, Ariz.

Jan 1, 1952

July 1-Sept. 30, Centennial of Engineering, Chicago. Aug. 28-29, Oak Ridge Summer Symposium, Oak Ridge, Tenn. Sept. 3-8, AIME, Industrial Minerals Div., annual fall regional meeting, Chicago. Sept. 3-6, AIME, fall meeting, Palmer House, Chicago. Sept. 3-13, AIME, Chicago Section, Centennial of Engineering, Chicago. Sept. 5-6, Engineers' Council for Professional Development, annual meeting, Hotel Sheraton, Chicago. Sept. 10-12, Porcelain Enamel Institute, annual shop forum, University of Illinois, Palmer House, Chicago. Sept. 11-13, American Institute of Chemical Engineers, Palmer House, Chicago, ill. Sept. 18, AIME, Utah Section, Newhouse Hotel, Salt Lake City. Sept. 22-25, American Mining Congress, Metal and Nonmetallic Mining Convention and Exposition, public auditorium, Denver.

Jan 1, 1952

Organization Place Date 1913 Mining and Metallurgical Society of America New York, N. Y. Jan. 8 American Institute of Electrical Engineers New York, N. Y. Jan. 11 American Society of Civil Engineers New York, N. Y. Jan. 22-25 American Society of Heating and Ventilating Engineers : New York, N. Y. Jan. 22-25 American Institute of Mining Engineers New York, N. Y. Feb. 18-21 National Society for Promotion of Industrial Educa- tion New York, N. Y. Feb.. American Institute of Architects Washington, D. C. April American Iron and Steel Institute New York, N. Y. May New York Electrical Society New York, N. Y. June National Association of Stationary Engineers Cincinnati, 0. Sept. American Chemical Society Cleveland, 0. Sept.

Jan 1, 1918

[Trans. No. Place Date Vol. Page 1, Wilkes-Barre, Pa.* .... May, '71.. 1 3 2. Bethlehem, Pa Aug., '71.. 1 10 3 Troy, N. Y Nov.,'71.. 1 13 4. Philadelphia, Pa Feb., '72.. 1 17 6. New York, N. Y •.... May, '72.. 1 20 6. Pittsburgh, Pa..:.Oct., '72.. 1 25 7. Boston, Mass Feb., '73.. 1 28 8 Philadelphia, Pa.' May, '73.. 2 3 9. Easton, a Oct., '73.. 2 7 10. New York, N. Y Feb., '74.. 2 11 11. St. Louis, Mo.* May, '74.. 3 3 12. Hazleton. Pa Oct.. '74.. 38 13. New Haven, Conn Feb., '75.. 3 15 14. Dover, N. J.' May, '75.. 4 3 16. Cleveland, 0 Oct., '75.. 4 9] [ ]

Jan 1, 1925

Jan 1, 1947

By Charles H. Hopkins, J. M. Lohr

A commercial development requiring a suitable alloy or alloys for sealing into various grades of glass made it desirable to have a more exact knowledge of the expansion characteristics of the nickel-iron alloys than appeared in the published literature. The expansion of the more common types of glass under consideration varies from 2.7 to 10.4 X 10-6 per degree Centigrade, over the range 20" to 400' C. For reference, the t,hermal expansion curves of several types of glass used for sealing by the lamp and tube industries are given (Figs. 1 and 2). This paper covers a detailed investigation of the thermal expansion of a series of nickel-iron alloys in which the nickel content varies from 30 to 70 per cent. Particular stress is laid on the alloys that contain between 40 and 55 per cent Ni.

Jan 1, 1939

By John T. Grasso

This paper describes the computer-assisted development and implementation of new written examinations for persons desiring to become certified as underground or surface mine electricians in the State of West Virginia under the certification program defined by the WV Department of Mines and the Board of Miner Training, Education and Certification. The procedures used to develop and validate the new certification tests have simplified the administration of the new tests. Future developments in mine electrical work can also be easily incorporated into the certification program by augmenting the existing computerized pool of test questions prior to computer-production of future test forms. Most important, computerization now facilitates continual evaluation of the certification program, to contribute to greater safety in mine electrical work in West Virginia.

Jan 1, 1983

By T. V. Subrahmanyam, A. P. Rao

The adsorption behavior of chalcopyrite has been studied at different xanthate concentrations and flow rates in a column apparatus with potassium ethyl xanthate as the collector. Based upon the experiment results an equation of the type: 1/F = K3 + m3C + k2/t.Cm2.fm1 is proposed to account for the experimental data. Among copper minerals an early study on chalcocite by Gaudin and Schuman (Taggart, 1951) is well known for its research on the kinetics of the reaction by conventional method of mass balance between the products of reaction and xanthate consumed. The results were interpreted by the concept of ion exchange adsorption. Szeglowski (1977) conducted measurements on the adsorption of potassium ethyl xanthate on copper polarized to various potentials, the adsorption being measured by radio-tracer techniques. The adsorption in the range -1800 to 700 mv was found to be a reversible physical adsorption. The potential range in which the primary electrode process could lead to surface coverage with a minimum number of product layers was evaluated. The adsorption density of xanthate on sulfide surface was found to be related to the concentration of xanthate in solution and concentration of depressants as: [ ]

Jan 1, 1983

By Charles H. Hopkins, J. M. Lohr

A commercial development requiring a suitable alloy or alloys for sealing into various grades of glass made it desirable to have a more exact knowledge of the expansion characteristics of the nickel-iron alloys than appeared in the published literature. The expansion of the more common types of glass under consideration varies from 2.7 to 10.4 X 10-6 per degree Centigrade, over the range 20" to 400' C. For reference, the t,hermal expansion curves of several types of glass used for sealing by the lamp and tube industries are given (Figs. 1 and 2). This paper covers a detailed investigation of the thermal expansion of a series of nickel-iron alloys in which the nickel content varies from 30 to 70 per cent. Particular stress is laid on the alloys that contain between 40 and 55 per cent Ni.

Jan 1, 1939