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R. E. Powers (Mellon Institute of lndustrial Research, University of Pittsburgh, Pittsburgh)—Several of the processing methods at the Josephtown smelter might well be considered by plants producing iron blast furnace sinter. In making blast furnace sinter the objectives are much the same as at Josephtown: To produce a strong yet porous agglomerate which has a size consist in a preferred range. The emphasis however is on production rate rather than on the size or other quality characteristics of the sinter. Therefore the technique is entirely different. Blast furnace sinter plants attempt to make their product in one pass with a minimum recirculating load and without sizing treatment after the sinter leaves the machines. Many plants are beginning to feel that more attention paid to quality characteristics would make the product a more desirable blast furnace material. The pelletizing of very fine material before placing it on the bed is not deliberately done at iron sinter plants, although the installed equipment sometimes gives a simila; action. Such pelletizing seems to be a promising way of accommodating the down-draft sintering Drocess to very fine materials. he recirculating load at Josephtown is extremely high. Two plants' producing blast furnace sinter from raw material of comparable size have a recirculating load of about 100 pct of production. At Josephtown it is notable that the size and the rate of feeding of return fines are under control. This is not the case in most blast furnace sinter plants. The sinter slicer appears to be a worthwhile aid in effecting such control. It is similar in action to rakes and plows used at a number of plants, but it has the advantage that the sinter dislodged is positively removed and not left to the inefficient action of a stationary grizzly screen. Blast furnace size specifications for sinter are not at present so rigid as the Josephtown specifications. If the sizing of blast furnace sinter does become important, then the Josephtown crushing practice, in which a large recirculating load is maintained on the crusher in order that minimum fines be produced, may be of interest. H. K. Najarian (authors' reply)—We note that Mr. Powers appreciates some points that we tried to emphasize in our paper as being of importance in making zinc sinter of good quality and which may well be applied to iron blast furnace sinter. Fig. 2 shows the pelletized nature of the feed going on to a Dwight-Lloyd type sintering machine in our plant. Practically, the entire feed consists of more ,or less rounded particles which permit more uniform air passage through the charge, while the larger particles in the charge roll on to the surface of the grate, which helps to keep the grate openings from being clogged by excessive fines. An agglomerated charge of this character may preferably be made by rolling action while being mixed in a rotating drum and wetted by water sprays to bind the fine particles together and give the charge the desired moisture content. From our observations of several iron ore and blast furnace flue dust sintering operations, we believe that if the fines from the sinter discharged from the machines were to be recirculated and agqlomerated with the new feed, not only sinter of better quality but larger capacity from the machines may be realized.

Jan 1, 1952

By Homer Turner

COALS, other than anthracite, have been so thoroughly studied under the microscope during recent years, that we now know what kinds of plants and what parts of plants form the bulk of lower rank coals from peat to bituminous coal. The microscope has also shown the state of preservation of such vegetation as well as the nature and distribution of products of plant decay. These and further details have been ascertained mainly through the employment of two methods of attack, section cutting and maceration. Anthracite has failed to respond to these methods, so well adapted to the study of lower rank coals and, therefore, has been neglected by investigators to such an extent that there is much doubt as to its microscopical characteristics. The object of this paper is to lift anthracite from its realm of obscurity by demonstrating the wealth of microscopical detail that is revealed when reflected light is used on a properly polished and etched surface and, further, to show the relationship between anthracite and bituminous coal.

Jan 2, 1925

By William H. Spice

The fault zone of south central Texas showed renewed activity during I940 along a trend roughly paralleling the old established Balcones fault-line group of producing fields. This was a result of the new discoveries in the Wilcox (Eocene) formation in southeastern Texas and Louisiana. As of the end of the year, one new field producing from the Wilcox formation had been discovered on the Washburn ranch in La Salle County, along the southwestern limits of the district, and several projected tests into that formation were under way. In the western part of the district, par-titularly in the part of the Rio Grande embayment that is in Dimmit, Webb and Zavala Counties, there has been renewed leasing activity with the shallower sands in the Navarro-Taylor formations (Upper Cretaceous) as the objective in several projected tests for the early part of 1941. Three new fields have been discovered along the old fault-line trend, but these have been comparatively small, producing either from Dale lime, Austin chalk or Buda lime. No new fields were discovered during the Year in the Edwards (Lower Cretaceous) lime horizon. Approximately 260 wells were drilled in the district during 1940, which resulted in four new oil fields. Twenty-seven new wells were completed in the Proven Edwards lime fields of Darst Creek, Luling and Salt Flat and seven were added to production in the Pearsall field. Approximately 160 wells in 18 counties were completed as failures during the year. The district produced 7,659,634 bbl. during 1940, which was a 9 per cent decrease under production for 1939. In all, 3559 wells were producing at the end of I940, compared with 3562 wells producing at the end of the previous year; 104 new producing wells were completed and 163 wells were abandoned in the producing fields of the district. During 1940 considerable exploratory work was carried on along the Wilcox trend within the district, particularly by major companies employing various types of geophysical methods, and leasing activity increased considerably. At the end of the year, the total number of acres of nonproducing leases held by major companies in the district increased about 10 per cent. It is anticipated that this activity will continue into the first part of 1941 and will be supplemented by several exploratory test wells. New Fields B,, Creek, Caldwett County.— . R. Ogden NO. 2 Talley, discovery well of the Bee Creek field, in the northeastern part of Caldwell County, was completed on March 16, I940, in Dale lime from 2091 to 2238 ft., pumping 85 bbl. per day, 39° A.P.1. gravity. The discovery of this field can be credited to a combination of subsurface geology and magnetometer work, which indicated the presence of a serpentine intrusion. At the end of the year, ,3 producing oil wells had been completed and the field has produced a total of 47,050 barrels.

Jan 1, 1941

By William H. Spice

The fault zone of south central Texas showed renewed activity during I940 along a trend roughly paralleling the old established Balcones fault-line group of producing fields. This was a result of the new discoveries in the Wilcox (Eocene) formation in southeastern Texas and Louisiana. As of the end of the year, one new field producing from the Wilcox formation had been discovered on the Washburn ranch in La Salle County, along the southwestern limits of the district, and several projected tests into that formation were under way. In the western part of the district, par-titularly in the part of the Rio Grande embayment that is in Dimmit, Webb and Zavala Counties, there has been renewed leasing activity with the shallower sands in the Navarro-Taylor formations (Upper Cretaceous) as the objective in several projected tests for the early part of 1941. Three new fields have been discovered along the old fault-line trend, but these have been comparatively small, producing either from Dale lime, Austin chalk or Buda lime. No new fields were discovered during the Year in the Edwards (Lower Cretaceous) lime horizon. Approximately 260 wells were drilled in the district during 1940, which resulted in four new oil fields. Twenty-seven new wells were completed in the Proven Edwards lime fields of Darst Creek, Luling and Salt Flat and seven were added to production in the Pearsall field. Approximately 160 wells in 18 counties were completed as failures during the year. The district produced 7,659,634 bbl. during 1940, which was a 9 per cent decrease under production for 1939. In all, 3559 wells were producing at the end of I940, compared with 3562 wells producing at the end of the previous year; 104 new producing wells were completed and 163 wells were abandoned in the producing fields of the district. During 1940 considerable exploratory work was carried on along the Wilcox trend within the district, particularly by major companies employing various types of geophysical methods, and leasing activity increased considerably. At the end of the year, the total number of acres of nonproducing leases held by major companies in the district increased about 10 per cent. It is anticipated that this activity will continue into the first part of 1941 and will be supplemented by several exploratory test wells. New Fields B,, Creek, Caldwett County.— . R. Ogden NO. 2 Talley, discovery well of the Bee Creek field, in the northeastern part of Caldwell County, was completed on March 16, I940, in Dale lime from 2091 to 2238 ft., pumping 85 bbl. per day, 39° A.P.1. gravity. The discovery of this field can be credited to a combination of subsurface geology and magnetometer work, which indicated the presence of a serpentine intrusion. At the end of the year, ,3 producing oil wells had been completed and the field has produced a total of 47,050 barrels.

Jan 1, 1941

By T. G. Digges, M. R. Achter

ALTHOUGH zone melting has found favor in recent years because of its convenience and its faster rate of production of single crystals, the older technique of strain annealing still has a number of advantages. It has been reported1 that the lattice of a crystal prepared in this manner has fewer defects than one grown from the melt and, of course, the control of the external geometry is easier. Also, the diameter of the crystal which can be grown by zone melting has a theoretical limit determined by the surface tension, thermal conductivity, and specific gravity of the material, while the size of that which can be grown in the solid state is limited only by practical considerations. In a program for the study of the structure-sensitive properties of niobium and its alloys it was desirable, for ease of handling, to have available single crystals of large diameter. This requirement dictated the choice of the strain-anneal technique. Induction heating was chosen in the present work in preference to other methods because of its deep penetration of large-diameter sections. A five-turn coil, powered by a motor generator operating at 10,000 cps, is contained in a vacuum chamber. The work is lowered through the coil for both the recrystallization and the crystal-growth steps. Starting with electron-beam melted material, the bars are cold-swaged, recrystallized, strained in a tensile machine, and then subjected to the growth step. Single crystals have been grown under the following conditions: Reduction in area during swaging— 79 to 99 pct, recrystallization temperature—1500o to 1667°C at the rate of 1.25 in. per hr, strain—1.0 to 2.5 pct, growth temperature—1600o to 2400°C at rates from 0.15 to 1.25 in. per hr. Starting grain sizes achieved after the recrystallization step varied from 0.6 to 1.55 mm. The starting grain size was found to be critical; if it is too fine and has any residual cold work, as shown by the presence of a fiberlike texture, a single crystal cannot be grown. Using this technique niobium single crystals have been grown from 0.250 in. diameter and 12 in. long to 1.00 in. diameter and 5 in. long as shown in Fig. 1. The 1-in. crystal is the largest to be reported for a refractory metal as compared to 0.500 in. for molybdenum grown by zone melting.2 As with zone melting, control of orientation is possible by the use of special procedures. Other investigators, see for example Williamson and Smallman,3 have reported that orientation control may be achieved by a bending technique. In the present work the strained rod is partially lowered through the coil to start the growth of the crystal. Then it is removed and bent at a point ahead of the interface between the single and polycrystalline portions. Finally, it is returned to the chamber and growth is continued "around the corner". The amount of bending which can be imparted to the rod is limited by coil geometry which up to now has been 10 deg. However, by repeating the bending and growing operations it should be possible to attain any desired orientation. The perfection of these single-crystal specimens as a function of process variables is being measured by X-ray and metallographic techniques and the results will be reported in a forthcoming paper. This work was partially supported by the Advanced Research Projects Agency.

Jan 1, 1964

By W. J. Tait, A. E. Craig, E. P. McCurdy

The Circuitron herein described applies current from the classifier motor circuit and energy from the sound of grinding media to move an oscillating disc. The disc through a photoelectric cell controls the speed of the ore feeder and consequently the amount of ore delivered to the mill. THE Telluride Mines, Inc. at Telluride, Colo., is operating a flotation concentrator recovering lead, zinc, and copper with some gold and silver. The nominal capacity is 500 tons per 24 hr. The ore, which comes from several different mines, is characteristic of the district, changing from extremely tough rhodonite to soft gouge. The ore is crushed and washed, recrushed, and delivered to the mill bin at about % in. to serve as ball mill feed. Details of Grinding Circuit The material from the fine-ore bin is carried over a belt feeder driven by a Reeves vari-speed device. The belt discharges to a No. 86 Marcy ball mill, which operates in closed circuit, with jigs and a 6-ft Dorr classifier. A Massco density controller holds the density of the classifier overflow at a predetermined point. The overflow, which contains about 5 pct + 48 mesh, goes to the flotation section. Manual Operation Before the adoption of automatic control for the grinding circuit, this work was all done manually by the operator. The bin gate was set to deliver 40 to 50 lb of ore per lineal foot of belt, and the speed of the belt was adjusted by the operator to deliver at the rate of about 500 tons per 24 hr. As the ore changed in hardness, specific gravity, or in the amount of moisture, or, as the size of the feed changed due to bin segregation, crusher setting, or other causes, the operator made corresponding changes in the rate of feed by manipulation of the Reeves control. Sometimes these changes occurred so rapidly that they caused sharp, pronounced surges, which created very considerable unbalance from normal conditions in the grinding circuit and, more critically, in the flotation section. Since it is not possible for the operator to anticipate or follow such changes closely, a very considerable unbalance from normal conditions may occur, which will require a drastic change in the rate of feed. These surges upset the fineness of grind and interfere radically with the balance between tonnage and reagent control. All of this tends to reduce the grade of concentrates, increase the loss in the tailing, and thus decrease the recovery of values. The Circuitron Some years ago, The Mine and Smelter Supply Co., in conjunction with the operators at the Telluride Mill, undertook to build a device that would give close control of the rate of feed from the ore bin and to coordinate with this a related device that would regulate the amount of sand load on the classifier rakes. Emphasis was strongly laid on the fact that such a control must apply to the entire grinding circuit and must include the feed to the ball mill, the classifier sand return, and the density of the classifier overflow. If this could be done successfully, we felt that the circuit could be operated under best possible conditions, with compensations

Jan 1, 1951

By E. P. McCurdy, W. J. Tait, A. E. Craig

The Circuitron herein described applies current from the classifier motor circuit and energy from the sound of grinding media to move an oscillating disc. The disc through a photoelectric cell controls the speed of the ore feeder and consequently the amount of ore delivered to the mill. THE Telluride Mines, Inc. at Telluride, Colo., is operating a flotation concentrator recovering lead, zinc, and copper with some gold and silver. The nominal capacity is 500 tons per 24 hr. The ore, which comes from several different mines, is characteristic of the district, changing from extremely tough rhodonite to soft gouge. The ore is crushed and washed, recrushed, and delivered to the mill bin at about % in. to serve as ball mill feed. Details of Grinding Circuit The material from the fine-ore bin is carried over a belt feeder driven by a Reeves vari-speed device. The belt discharges to a No. 86 Marcy ball mill, which operates in closed circuit, with jigs and a 6-ft Dorr classifier. A Massco density controller holds the density of the classifier overflow at a predetermined point. The overflow, which contains about 5 pct + 48 mesh, goes to the flotation section. Manual Operation Before the adoption of automatic control for the grinding circuit, this work was all done manually by the operator. The bin gate was set to deliver 40 to 50 lb of ore per lineal foot of belt, and the speed of the belt was adjusted by the operator to deliver at the rate of about 500 tons per 24 hr. As the ore changed in hardness, specific gravity, or in the amount of moisture, or, as the size of the feed changed due to bin segregation, crusher setting, or other causes, the operator made corresponding changes in the rate of feed by manipulation of the Reeves control. Sometimes these changes occurred so rapidly that they caused sharp, pronounced surges, which created very considerable unbalance from normal conditions in the grinding circuit and, more critically, in the flotation section. Since it is not possible for the operator to anticipate or follow such changes closely, a very considerable unbalance from normal conditions may occur, which will require a drastic change in the rate of feed. These surges upset the fineness of grind and interfere radically with the balance between tonnage and reagent control. All of this tends to reduce the grade of concentrates, increase the loss in the tailing, and thus decrease the recovery of values. The Circuitron Some years ago, The Mine and Smelter Supply Co., in conjunction with the operators at the Telluride Mill, undertook to build a device that would give close control of the rate of feed from the ore bin and to coordinate with this a related device that would regulate the amount of sand load on the classifier rakes. Emphasis was strongly laid on the fact that such a control must apply to the entire grinding circuit and must include the feed to the ball mill, the classifier sand return, and the density of the classifier overflow. If this could be done successfully, we felt that the circuit could be operated under best possible conditions, with compensations

Jan 1, 1951

By Robert L. Marovelli

A recent reorganization placed the health and safety research activities of the Bureau of Mines under a director, Division of Minerals Health and Safety Technology. The new health and safety research organization and its position in the Bureau hierarchy is shown in Table 1.

Jan 11, 1979

By D. H. Baldwin, R. E. Reed-Hill

DURING the course of experiments involving oxygen equilibrations with a high-purity Pd-5 at. pct Rh alloy, the appearance of a subscale was noted. Most of the heat treatments in a pure oxygen atmosphere were performed at 900°C. The presence of the subscale was noted when the oxygen partial pressure was in excess of approximately 95 mm, up to 1 atm, the highest pressure used. According to available thermodynamic information' on the free energy of formation of Rh2O3 (the only reliably reported solid oxide of rhodium), this oxide should not be stable under these conditions, nor, of course, any oxide of palladium. Extraction of the subscale from the matrix was affected by treatment with aqua regia, and the resulting X-ray diffraction powder pattern is shown in Table I. This pattern is not that of Rh2O3, nor that of any known rhodium or palladium oxide. It can be indexed on a hexagonal lattice with a. = 5.22Å and co = 6.0Å. In addition to this unknown material, there was a weak Rh2O3 pattern. An X-ray fluorescence analysis of the powder gave 3214 palladium counts per sec and 5381 rhodium counts per sec, thus indicating the likelihood of a double oxide of palladium and rhodium. In view of the fact that the above result was obtained on a single sample, it is perhaps best not to insist upon the above ratio of about 0.6, but possibly to tentatively assume 0.5 or 1/1. The small amount of Rh2O3 in the X-ray pattern might have occurred on cooling, and it seems possible that the double oxide, below some temperature level, is not as stable as Rh2O3. To examine this point, some of the extracted double oxide was heated on a sheet of pure palladium in air at 900°C, and allowed to furnace-cool over a period of several hours. The X-ray diffraction pattern of the powder showed approximately the same intensity of Rh2O3 and the "hexagonal" oxide as before, but, in addition, a rather faint pattern of another crystalline species made its appearance. This finding again suggests partial transformation of the major (double) oxide to other oxides on cooling from 900°C. Application of the phase rule shows that only one equilibrium oxide (subscale) could have been present at temperature. Vacuum-fusion, oxygen analysis of the extracted subscale showed 7.7 ± 0.7 pct O. Combining this information with that of the X-ray fluorescence analysis suggests the formula PdRhO. This compound should have an oxygen content of 7.07 pct, which is within the range of error of the oxygen analysis. However, until a more careful stoichiometric study is made, it is suggested that the formula be written

Jan 1, 1965

The Palabora ore consists of two types, a carbonatite containing a low titanium magnetite, and a foskorite containing high titanium magnetite. The latter type also contains substantial quantities of phosphate. These two ore types are separately crushed and are kept separate through copper flotation and magnetic separation, for recovery of magnetite, with the low Ti magnetite being shipped as iron ore. High phosphate tailings are pumped to Foskor, a government-owned phosphate plant nearby. The Palabora plant was originally designed in 1966 for 33, 000 tpd using two 54 in. by 74 in. Allis -Chalmers gyratories; two 7 ft (2. 13 m) standards; four 7 ft shortheads; and six grinding lines, each using one 1,200 hp rod mill and two 1,200 hp ball mills. A fifth short- head and one more grinding line were added later; and with flowsheet improvements, the capacity of the plant was increased to 59, 500 stpd. A further plant expansion involving a third 54 in. primary and two 32 ft by 15 ft (9.75 by 4.6 m) 9,000 hp autogenous mills and another flotation section will bring its capacity to 87,500 stpd in 1977. These two fully autogenous mills are constructed entirely out of doors near the primary crusher, and the ground ore will be pumped a mile to the concentrator by a five-stage pumping system. The Palabora ore is mined with 6, 10, and 12 7d (4.6, 7.6, and 9. 2 cu m) shovels and hauled to the crushers in 110 and 165 st trucks. Sixty-five ton trucks were originally used, but the crusher dump pockets were designed for larger units. Dump pockets, crushers, feeders, and take- away belts are offset in order to keep the two ore types separate. Centerlines of the crushers are only 43 ft (13. 1 m) apart; but, because of their being offset, maintenance room is ample. Initially, more carbonatite ore than foskorite was mined; but as the pit has deepened, this ratio has been reversed. The Palabora ore breaks in the pit with a large amount of oversize boulders; and, with the use of larger trucks, a splitter has been installed on one side of each dump pocket to protect the crusher spider. Smaller trucks dump on the opposite side. To accomodate the splitter, the pocket edge has been raised one meter and moved back one meter. Dust is collected through a special vent shaft between the crushers and the mantle relining area; but even so, two high-pressure water spray headers with nozzles are installed under the edge of the pocket at each dumping position. While only one truck dumps at a time, sprays from all four headers are used to suppress dust. Any leakage of water through the seal around the upper bowl of the crusher is caught by a circular trough under the seal and directed to a sump pump. At this point, there

Jan 1, 1978

By V. Apraxine, J. Lakaye, J. J. Saquet, P. Troch

Union Minière du Haut-Katanga owns concessions for extracting copper and associated metals in the high plateau region of Katanga. The concession is about 188 miles long by 44 miles wide and has three principal areas: Southern area-The Prince Leopold mine is an underground operation from which a copper-zinc sulfide ore is extracted. The mine and associated concentrator are at Kipushi. Copper concentrates are smelted and converted to blister copper at the Lubumbashi smelter at Elizabethville.

Jan 12, 1962

By J. L. Huitt, B. B. McGlothlin, D. K. Lowe

Published correlations for the principal aspects of hydraulic fracturing were combined into a digital computer program to facilitate the study of interrelated variables. The computer program includes individual relationships for fracture width during pumping, fracture area generated, propping agent embedment, flow capacities of propped fractures and transport of propping agents in horizontal fractures. The effects of more than 20 treatment and formation parameters on the predicted results of hydraulic fracturing treatments were studied. The effects of these parameters were determined for (I) fracture width during injection, (2) fracture width after the overburden comes to rest on the propping agents, assumed not to be crushed, (3) generated and propped fracture area, (4) location and concentration of propping agents in the fracture when injection ceases, (5) flow capacities of the various propped sections of the fracture and (6) expected increase in the well productivity. The effects of propping agent, formation and fracturing fluid parameters on well productivity are discussed. The parameters that were found to have the most pronounced effects on hydraulic fracturing treat~nents are injection rate, treatment volume, fracturing fluid coefficient, size and amount of propping agent, spearhead volume, well drainage radius and formation capacity. INTRODUCTION Many correlations have been published for predicting effects of various parameters that are considered in the design of hydraulic fracturing treatments. The Carter equation' can be used to predict generated fracture radius as a function of fracture width, fracturing fluid leakoff and other parameters. Fracture width can be determined by use of the Perkins and Kern correlation' in which the fracture width is related to the fracture radius, fluid injection rate and certain formation and fracturing fluid parameters. Wahl and Lowe et aL4 have reported methods of predicting the location of propping agents in fractures when pumping ceases. The former study is applicable to the case where the ratio of propping agent diameter to fracture width is less than 0.1. The latter is applicable when this ratio is greater than 0.1. These studies showed that the propping agent placement in horizontal-radial fractures depends principally on how the individual particles are transported in the fracture by the carrying fluid. Particle transport in fractures is determined by local fluid velocity in the fracture, fluid and particle properties, and the size of the particle relative to the fracture width. The distribution of propping agents, effective overburden pressure and formation rock strength control the propped fracture width6 by controlling the extent to which the propping agent particles embed into the fracture faces. From the distribution of propping agents and the propped fracture width, fracture flow capacities can be calculated or the various regions of the fracture. The flow capacities and the radial extent of these regions can be combined with reservoir information to predict the productivity increases for fractured wells. In all these studies, the effects of certain treatment and/ or reservoir parameters on one facet of fracturing can be predicted only if other facets which the parameters affect are fixed. For instance, fracture width and radius are interrelated; that is, to calculate the value of one, the value of the other must be known. Also, some parameters influence more than one aspect of fracturing. For example, prop-pant transport is a function of both fracture width and fluid viscosity. but fracture width is itself a function of fluid viscosity. Since these calculations are complex and the parameters interrelated, it is not possible to write an equation with which the over-all effects of treatment parameters can be solved explicitly. For these reasons, the correlations for determining the effects of the parameters which are most significant in hydraulic fracturing treatments have been incorporated into a digital computer program. COMPUTER PROGRAM The program, which was written for an IBM 7094 computer, can be used to predict results of most of the combinations and values for the treatment parameters that are ordinarily considered for fracturing treatments. A spearhead of fracturing fluid and a propping agent-carrying fluid with different fluid properties can be taken into account. Also, the total volumes and relative amounts of the spearhead and carrying fluids can be varied. Two different propping agents (as used in tail-in operations) and a wide range of formation properties and injection rates are considered. The computer program (Fig. 12) consists of several sets of calculations. First, the final flooded fracture radius and average fracture width at the cessation of pumping are calculated. This is done by simultaneous solution of the Perkins and Kern fracture width equation and the Carter equation for flooded fracture radius (equations used in the computer program appear in the Appendix). The next step is to determine local fluid velocity in the fracture as a function of time and radius. Since it is not possible to write this function in closed form expression, a table of velocity values is generated by the program and stored for subsequent use. The time span from the beginning of

MORE than 5000 miners and suppliers descended upon Denver to make the American Mining Congress' four-day metal mining show one of the most extravagant equipment displays ever assembled in one place at one time. The most recent developments in equipment for mining, milling, and processing ore were shown by the 146 exhibitors at Denver's new City Auditorium which covers 57,000 sq ft of floor space. Other displays were placed in the open air opposite the auditorium site. Registration desks were opened Sunday, Sept. 21. A field trip to the Colorado School of Mines at Golden was the featured activity of the day. Official opening of the show took place on Monday, and presided over by Howard I. Young, president of American Zinc, Lead & Smelting Co.; Otto Herres, vice president, Combined Metals Reduction Co.; William J. Coulter, vice president, Climax Molybdenum Co.; Charles B. Stainback, Westinghouse Electric Corp.; and Merrill E. Shoup, president, Golden Cycle Corp. Convention welcoming addresses were delivered by a representative of Mayor James Q. Newton, of Denver, and Gov. Daniel V. Thorton of Colorado. Following the formal opening ceremonies a round table discussion dealt with the "Paley Commission Report" formally called Resources for Freedom. Participating in the panel were: Arthur H. Bunker and George R. Brown, members of the Paley commission; H. I. Young, president of the American Mining Congress; Horace M. Albright, president of U. S. Potash Co.; Evan Just, vice president, Cyprus Mines Corp.; Donald H. McLaughlin, president, Homestake Mining Co.; E. H. Snyder, president Combined Metals Reduction Co.; Simon D. Strauss, vice president, American Smelting & Refining Co.; Sen. H. C. Dworshak (R.-Idaho) ; Ira B. Joralemon, consulting engineer; Jess Larson, De fense Materials Procurement Agency; and Andrew Fletcher, president of St. Joseph Lead Co. The panel discussed the report for six hours, adding a great deal of information to the already voluminous amount which has been gathered concerning it. Three objections to the report frequently mentioned were: 1-the multilateral contract; 2-international buffer stocks; 3-international buffer stocks combined with limited quota arrangements. Points on which the panel commended the report were its recommendations for acceleration of topographic and geologic mapping of the United States and Alaska; recognition of the principle of percentage depletion for metals and minerals; and advocation of removal of the present limitations on the expensing of exploration costs applicable to minerals. Technical sessions were held throughout the four days of the meeting. Included in the program were: Progress in Mechanication; Small Mines; Public Lands; Open Pit Mining; Manpower-Labor Relations; Shaft Sinking; Roof Support; Taxation, Gold, Silver and Monetary Policy; Advances in Mill Practices; Special Conference on Strategic Materials; Uranium Mining-Atomic Energy; Prospecting and Exploration; New Metallurgical Processes; and Rock Breaking. About 45 papers and several panels were presented during technical sessions. Formal and informal social functions consumed the remaining time of the convention. Three locations were needed to handle the huge throng attending the Mining Jamboree Monday evening. The only other sponsored social function took place Thursday evening. A great many informal gatherings, chiefly convivial, were held in manufacturers' courtesy rooms-called wet stopes. Field trips included Cripple Creek, Pueblo, Climax -Leadville-Gilman, Colorado Plateau-Grand

Jan 1, 1952

By R. Q. Shotts

Data are presented which show that fractions of varying densities from the same coals are oxidized at different rates by nitric acid. From oxidation data, the approximate quantity of "bright" and "dull" components may be calculated. Definite relationships between oxidation rate and rank are shown for density fractions from at least two bituminous coals. IN 1945, the Alabama State Mine Experiment Station initiated a program on the determination of fusain in certain coals of the state.1 Because of the lack of equipment and personnel necessary for microscopic examination, the chemical method2 was used exclusively. During studies of the distribution of fusain in fractions of various sizes and densities on a medium volatile coal, the author noted a higher rate of oxidation of the nonfusain part of the coal in the lower density fractions and the difference in rate became more marked the shorter the oxidation period used. Since durain and other "dull" components of coal have been reported3,4,5 to have higher densities than vitrain and the bright components, it appeared probable that the observed differences in rates of oxidation in the different density fractions were due to variations in petro-graphic composition. Such effects have been noticed by other workers.2,3 In order to obtain further evidence on this point, several Alabama coals of different rank have been separated into three or more fractions on the basis of density and their rates of oxidation determined, using the procedure specified for the determination of fusain, except that measurements were made at short time intervals as well as for the longer periods specified in the regular procedure. Significant differences in the rates of oxidation of the nonfusain part of the various fractions have been observed, and it is believed that studies of this type may make possible the identification of individual petrographic components or lead to methods for their semiquan-titative estimation. Properties of the Coals: Analyses and some properties of the whole coals studied are given in table I. The range in rank of the coals is not the widest possible within the state, but samples of the low volatile coals that occur in thin beds in the northeastern part of the state, were unavailable. The Clements bed is not, at present, considered workable. The coal is of medium volatile rank, quite friable, and very strongly swelling. Analyses of different size fractions show that the larger sizes are of higher rank than the smaller ones. Material passing the No. 50 sieve (all sieve sizes refer to the U. S. Standard Series) is close to high volatile A in rank, except for the size passing a No. 200 sieve, in which fusain is partially concentrated. Because of the variation in rank of the sizes of Clements coal, oxidation studies were made of two widely different size ranges. The + 1-in. material was crushed on rolls to about 1/8 in. and separated into five fractions by float-and-sink treatment in a benzene-carbon tetrachloride mixture. The — No. 4 + No. 8 and the — No. 4 + No. 50 size ranges tested overlap but the latter size was studied last with the expectation that it would include more oxidizable material than the first size. This proved not to be the case. Yields and properties of the specific gravity fractions oxidized are shown in table II. Milldale bed coal probably represents, as nearly as it is possible to do so, the "average" coal of the state. The material passing a No. 4 sieve was the only size range oxidized. It was divided into four specific gravity fractions. As in every case the heaviest fraction, which was essentially rock, was discarded. The Black Creek is the most extensive in area of

Jan 1, 1951

By R. Q. Shotts

Data are presented which show that fractions of varying densities from the same coals are oxidized at different rates by nitric acid. From oxidation data, the approximate quantity of "bright" and "dull" components may be calculated. Definite relationships between oxidation rate and rank are shown for density fractions from at least two bituminous coals. IN 1945, the Alabama State Mine Experiment Station initiated a program on the determination of fusain in certain coals of the state.1 Because of the lack of equipment and personnel necessary for microscopic examination, the chemical method2 was used exclusively. During studies of the distribution of fusain in fractions of various sizes and densities on a medium volatile coal, the author noted a higher rate of oxidation of the nonfusain part of the coal in the lower density fractions and the difference in rate became more marked the shorter the oxidation period used. Since durain and other "dull" components of coal have been reported3,4,5 to have higher densities than vitrain and the bright components, it appeared probable that the observed differences in rates of oxidation in the different density fractions were due to variations in petro-graphic composition. Such effects have been noticed by other workers.2,3 In order to obtain further evidence on this point, several Alabama coals of different rank have been separated into three or more fractions on the basis of density and their rates of oxidation determined, using the procedure specified for the determination of fusain, except that measurements were made at short time intervals as well as for the longer periods specified in the regular procedure. Significant differences in the rates of oxidation of the nonfusain part of the various fractions have been observed, and it is believed that studies of this type may make possible the identification of individual petrographic components or lead to methods for their semiquan-titative estimation. Properties of the Coals: Analyses and some properties of the whole coals studied are given in table I. The range in rank of the coals is not the widest possible within the state, but samples of the low volatile coals that occur in thin beds in the northeastern part of the state, were unavailable. The Clements bed is not, at present, considered workable. The coal is of medium volatile rank, quite friable, and very strongly swelling. Analyses of different size fractions show that the larger sizes are of higher rank than the smaller ones. Material passing the No. 50 sieve (all sieve sizes refer to the U. S. Standard Series) is close to high volatile A in rank, except for the size passing a No. 200 sieve, in which fusain is partially concentrated. Because of the variation in rank of the sizes of Clements coal, oxidation studies were made of two widely different size ranges. The + 1-in. material was crushed on rolls to about 1/8 in. and separated into five fractions by float-and-sink treatment in a benzene-carbon tetrachloride mixture. The — No. 4 + No. 8 and the — No. 4 + No. 50 size ranges tested overlap but the latter size was studied last with the expectation that it would include more oxidizable material than the first size. This proved not to be the case. Yields and properties of the specific gravity fractions oxidized are shown in table II. Milldale bed coal probably represents, as nearly as it is possible to do so, the "average" coal of the state. The material passing a No. 4 sieve was the only size range oxidized. It was divided into four specific gravity fractions. As in every case the heaviest fraction, which was essentially rock, was discarded. The Black Creek is the most extensive in area of

Jan 1, 1951

By F. G. Stone

A strain anneal process has been developed for the production of iron tensile test specimens, the gauge length consisting substantially of a single crystal. Since the method has been quite successful and the results of general interest, the process will be described in detail. The essential feature of the method is the continuous, slow increase of furnace temperature during the grain growth annealing treatment. Briefly, the procedure is as follows: I. Heat machined bars to 950°C in vacuum, hold I hr, furnace cool. 2. Strain to 3.5-3.8 pct elongation (axial loading). 3. Anneal, continuously raising furnace temperature from 450 to goo°C at a rate of so0 per day. 4. Hold at 900°C for 100 hr, furnace cool. Tensile test bars with a 1/4- X I-in. gauge section have been machined from 35 in. Armco iron plate and from 3/8 in. rounds of Puron, a high purity laboratory iron. The axes of the test bars were parallel to the rolling direction. During the machining operation the bars were polished in the lathe with No. 600 emery paper, and this polished surface proved satisfactory for subsequent macrographic examination. A micrographic examination of the materials showed that both were high in FeO inclusions, those of the Puron being smaller but much more numerous. An initial vacuum anneal of I hr at 950°C followed by furnace cooling resulted in a ferritic grain size of ASTM No. 3 for Armco and No. I for Puron. Special heat treatments which reversed these initial grain sizes produced no marked improvement in single crystal production after subsequent treatments. The strain for subsequent grain growth was determined by measuring the decrease in diameter of the tensile bar during elongation. The change in diameter could be measured with a micrometer to +0.0001 in., corresponding to an accuracy of 0.08 pct for the elongation. The accuracy of the diameter measurement is also dependent on grain size because of surface roughening during elongation, and for this reason, a No. 3 grain size is preferable. Optimum grain growth was obtained for strains between 3.5 and 3.8 pct elongation. Once this critical range had been cstablished, all tests were held within it, and thus only meager data were obtained on grain growth following strains outside this range. In general, grain size decreased with increasing strain to about 5.5 pct elongation. Grain growth was occasionally ohserved with less than 3.5 pct elongation although this may have been the result of error in measurement. The program control device for the grain growth anneal consisted of a I rpm motor and worm gear drive, operating the dial shaft of a pyrometer controller through a pulley. Dial speeds of 33 and 50°C per day were tried, but the results at the slower speed were not sufficiently better to warrant the increased furnace time. The furnace tube was evacuated at intervals during the run and kept sealed the remainder of the time. When the controller reached 900°C, it was stopped and the temperature held for 100 hr. This eliminated most of the numerous minute crystallites of about 0.5 mm dimension usually visible on the etched surface of the single crystal. Since recrystallization occurs at the A3 point, the top temperature of 900°C provided a 10"

Jan 1, 1949

By O. N. Carlson, D. G. Alexander

THE hardness anisotropy of metals and alloys has been of increasing interest in recent years but silicon ferrite,1 niobium,2 and tungsten3,4 are the only bcc metals about which this type of information has been reported. This investigation was carried out on vanadium and chromium single crystals in an effort to determine to what degree the hardness variations observed in these metals are due to orientation effects and to compare their behavior with other bcc metals. In earlier work the authors had observed a small angular dependence in the Diamond Pyramid Hardness of single crystalline vanadium on the (100) plane but no anisotropic effects were noted on either the (110) or (111) planes. At the suggestion of R. G. wheeler5 it was decided to investigate this effect in greater detail using the more asymmetric Knoop indentor. The vanadium metal used in the study was prepared by the aluminothermic reduction of V2O5 followed by electron beam melting.6 The principal analyzed impurities were 230 ppm C, 230 ppm O, 65 ppm N, 90 pprn Al, Cr not detected, 50 ppm Fe, 60 ppm Ni, and 200 ppm Si. The chromium was an iodide-refined product obtained from the Chromalloy Corporation. Analysis of this material showed the following amounts of impurities present: 10 ppm C, 9 ppm O, 2 ppm N, 0.4 ppm H, 3 ppm Al, 2 ppm Ca, 2 ppm Cu, 20 ppm Fe, 1 ppm Mg, 0.3 ppm Mn, 1 ppm Mo, 3 ppm Ni, 10 ppm Si, and 1 ppm V. Single crystals of both metals about 1 cm in diam and 10 cm in length were grown by an arc-zone melt- ing technique.7 The chromium crystal was annealed at 1600°C for 6 hr in a purified argon atmosphere to remove any strains or inhomogeneities, but the vanadium was tested in the as-grown condition. The crystals were oriented by the Laue back-reflection method and then sectioned with a spark cutter into individual specimens with a (loo), (110), or (111) plane parallel to the crystal surface. They were mounted in Lucite and carefully ground to a flat surface. The vanadium specimens were then electropolished in a 6 pct perchloric acid-methanol mixture while the chromium specimens were mechanically polished on a Syntron vibratory polisher using an alumina abrasive. The orientation of each crystal was then rechecked by the back-reflection X-ray method. All of them were found to lie within 2 deg of the desired orientation with the exception of the (110)-Oriented chromium crystal which was within 4 deg. Microhardness impressions were taken at 10 deg intervals from the common (110) direction by rotating the crystal in the plane of the crystal surface. A Knoop indentor was used with a 400-g load on the vanadium crystals and an 800-g load on the chromium. The hardness values are averages of 6 impressions and standard deviations were calculated for each set of data. The values reported for the (111) plane of vanadium are based on from 10 to 15 measurements for each point. The microhardness results for vanadium and chromium are plotted as a function of the angular rotation of the long axis of a Knoop indentor from the (110)

Jan 1, 1970

Elected Died 1895 ABBOTT, AI ATTHUR 1908 1882 ABBOTT, ARTHUR V 1906 1905 ABE, MASAYOSHI 1909 1903 ADAMS, CHARLES C. 1905 1906 ADAMS, JOHN C. 1913 1905 ADAMS, WILLAMS 1909 1903 ADAMS, W. EDWARDS 1910 1884 ADDY, MATTHEW 1896 1906 AFFLECK, WILLIAM A. 1911 1889 AKERS, WILLIAMS A. 1906 1905 ALABASTER, RUPPERT C. 1911 1899 ALBERGER, LOUIS R. 1911 1894 ALLEN R B 1896 1905 ALLEN, R. SCOTT 1906 1886 ALLISON, ROBERT 1916 1874 AMIOT, H. 1892 1886 AMSLER, CARL 1894 1898 ANDRSON, JOHN W 1905 1895 ÅNGSTROM, CARL 1901 1887 ARCHBALD, JAMES 1910 1900 ARLETT, GEORGE H 1906 1895 ARMSTRONG, JOHN F 1898 1905 ARNOLDS, LEO F. 1917 1882 ARNOLDS, HUGO 1886 1875 ASHBURNER, CHARLES A 1889 1872 ASIIBURNER, WILLIAM 1887 1883 ATKINS, C M , JR 1885

Jan 1, 1923

Lead-zinc production in Canada accounted for 19% of the total value of metals and minerals produced in 1976, says Keith C. Hendrick, president of Noranda Sides Corp. Mine production of recoverable zinc w as 1. 158 million toils of 27.4% of free world production in 1976. Slab zinc pro¬duction was placed at 472,000 tons that year. Canadian mine production of recoverable lead was 247,000 tons or 10.6% of the free world production. Refined lead that year was at 177,000 tons.

Jan 11, 1977

By Casimir Constable

DURING the years 1875 to 1879 I had charge of the Rockwood furnaces and mines, situated forty miles from the nearest railway communication at that time, and one hundred miles north of Chap tanooga, Tenn., by the Tennessee River. The small furnace with old-fashioned stoves, then in blast, was built under great difficulties by General Wilder. The early conditions were somewhat as follows: The ore was fossil ore of the Clinton group ; very fine and generally wet, without other admixture. The coke had a large amount of ash, and the fur" nace appeared to be badly scaffolded at times. On many days only a few tons of iron could be obtained. The founder generally id creased the revolutions of the engine when signs of chilling appeared,. The cinder at such times was black, very scoriatious, often closely resembling mill cinder. When the pressure was increased (the joints being the old-fashioned rust joints), leaks in the blast-pipe occurred It was noted that when the blast was stopped, and the leak bolt imperfectly remedied, the furnace improved a little. This set me thinking on the right track; and I took the responsibility of be coming my own founder for a time. A scaffolded condition had existed, and the situation was a trying one. Strange to say the negroes proved excellent furnace-men. Conceiving the hearth of the furnace to be similar to the grate area of a steam-boiler, capable of disposing of but so much fuel per hour, and requiring only a corresponding amount of air, it follows that an excess of air will burn the fuel not yet arrived at the hearth!, and raise the melting-point far above the tuyeres. This might pro duce scaffolding or at any rate choke the boshes, and leave less fuel to be consumed in the hearth. Thus for the time being less ail;. would be needed, as the continued burning of fuel in and above the boshes, would only aggravate the trouble. This condition of affairs accounted for the black cinder; the heat above having melted ore not yet perfectly reduced. This view decided me to reduce the revolutions of the engine; thefurnace finally became gray, as might have been expected. Any attempt to increase the speed produced black cinder and hard iron ;

Jan 1, 1883