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C. A. ROSE, New York, N. Y. (written discussion *).-Without doubt the excellent results obtained at Ajo will cause surprise among metallurgists; 75 per cent. average capacity and 80 per cent. extraction during the first year of operation of a plant using a new metallurgical process are figures that speak for themselves. It is obvious that the most troublesome feature of the process is the fouling of solutions. The effects of this are most evident in the electrolytic tank house; but apparently the solutions are so heavily loaded with salts that their dissolving power is also impaired. This is indicated by the fact that copper comes into solution during washing after the leaching of the ore is completed, as shown by the decreasing ratio of acid to copper in the various washes tabulated in Table 4, and also by the fact that 4.9 per cent. of the total copper in the ore remains in the tailings in a soluble form. Even though the extraction in leaching and the ampere efficiency in electrolysis would be benefited by keeping the salts in solution at a lower concentration, it is doubtful whether it would pay to decrease these salts by discarding more electrolyte without other changes in the, process, since this would increase the amount of cement copper produced, which is already very large. If, however, it would not disturb the process otherwise, this object could be accomplished by increasing the range of electrolysis, so that solution going to the tank house would contain, say, 4 per cent. copper and 1 per cent. acid, and the solution returned to the leaching plant 1 1/2 per cent. copper and 4.8 per cent. acid, and by increasing the volume of solution to be discarded, this to be taken from the electrolyzed solution returned to the leaching plant. By this arrangement, more salts will be removed from the system per ton of cement copper produced; and if sufficient solution is discarded to keep the iron content down to 1 1/2 per cent. it would he feasible to recover the copper from

Jan 4, 1919

By Francois E. Heuze

INTRODUCTION Rock slope stability typically is governed by the geological discontinuities. This stability can be improved by drainage, unloading, adjustment in slope orientation, adjustment in slope angle, and also by reinforcement such as bolts or tendons. This paper addresses the modeling of bolt reinforcement in rock slopes. Most geological discontinuities such as joints have rough surfaces; they dilate during shear displacement. Their shear strength is characterized by two envelopes (Fig. 1); the peak envelope is distinct from the residual envelope when the joints can dilate. If the dilation is restrained transversely, such as with bolts, the normal stress will increase and the joint strength also will increase. It has been demonstrated that this increase may be considerable (Obert et al., 1976). The new normal stress at peak strength is a com- posite function of the properties of the rock mass and of the steel (Heuze, 1979). Hence, the dilation and its resultant effects on joint shear strength must be included in the analysis and design of the reinforcement. We present a model which can be used to perform such an analysis. Early studies of rock reinforcement in mining and civil applications (Lang, 1957 - Panek, 1962 - Osen and Parsons, 1966 - Lang, 19721, did not consider the specific effects of bolts on joint shear strength. In 1973, Heuze and Goodman reported direct shear tests on rough sandstone joints with bolts perpendicular to the joint plane (Fig. 2). The peak shear strength of such joints was greatly in excess of the shear strength of the unbolted joints. The excess

Jan 1, 1983

THERE can be little doubt in the mind of anyone of the great interest which has been provoked in the mining and petroleum industry by the com-paratively new geophysical methods of prospecting, after the sessions at this year's meeting of the Institute. Not only were the sessions very well attended but every¬one seemed most attentive. Although the discussion was somewhat limited in general, that may well be at-tributed to the newness of the subject. Two sessions on this subject were planned originally, but these gave insufficient time for the presentation of all the papers prepared and a third session was abso-lutely necessary. The first meeting dealt entirely with the gravity methods and was completed in the scheduled time owing to the fact that but two of the five papers listed were read. The second session was devoted to magnetic and electrical methods, the completion of which had to be carried over into the third period of geophysics. The first session on geophysical prospecting, and in-cidentally the first scheduled Institute meeting devoted entirely to this subject, was most appropriately opened by E. L. DeGolyer, the chairman of the session. It was through the efforts of Mr. DeGolyer that the first gravity work, as applied to prospecting, was under-taken in this country. Again most appropriately, the first paper presented was given by Donald C. Barton, who carried on the first work with the Eötvös torsion balance in America and aided materially in its development. A subject, the theory of which is so difficult to understand as it is generally presented, was so clearly illustrated and ex-plained by the speaker that even a novice could grasp the fundamentals. Dr. Barton, in showing actual re-sults obtained in torsion balance surveys with the in-terpretation of the sane and later drilling records, was free in stating that there are many limitations to the field in which this and the other geophysical instruments may be successfully employed. This paper called for considerable discussion relative to the application of the torsion balance to gravity surveys over various types of structures. During the course of this discus-sion a very important point was emphasized by the chairman, namely, that for successful application of any or all of the scientific methods of prospecting, a back-ground of experience is absolutely necessary to serve as a basis for further work. This can only be secured by contributions from the results of actual prospecting work.

Jan 3, 1928

By Raymond D. Sloan

Dropping from third position among the oil-producing states of the nation in 1942, Oklahoma ranked fourth in 1943 with a total output of 121,431,ooo bbl., a decline of 11.9 per cent from the previous year's total of 137,792,000 bbl. Production ranged from a maximum of 346,900 bbl. daily in February to a low of 322,800 bbl. daily in October, and at the close of the year was averaging 330,000 bbl. daily from 52,096 wells, or an average of 6.3 bbl. per well. The state's well, average at the close of 1942 amounted to 6.7 bbl. At the turn of the year, it appeared reasonable to assume that Oklahoma's producing rate would continue its downward trend during 1944 unless reversed by greater than normal discoveries. To Jan. I, 1944, Oklahoma has produced 5,188,466,-ooo bbl. of crude oil. Development and Exploration A total of 1287 wells was drilled in 1943, representing an increase of 77 wells, or 6.4 per cent over the preceding year's total of 1210. Of the wells completed, 587 (45.6 per cent) were oil wells with an average initial production of 319 bbl.; 127 (9.9 per cent) were gas wells with an average initial of 8,639,000 cu. ft.; and 573 (44.5 per cent) were dry. A total of 333 wildcats was drilled (25.9 per cent of all wells), an increase of 13 (4.1 per cent) over the 1942 total of 320. Of the*wildcats drilled, 46 (13.8 per cent) were oil wells with an average initial production of 235 bbl.; 27 (8.1 per cent) were gas wells with an average initial of 8,249,-ooo cu. ft.; and 260 (78.1 per cent) were recorded as failures. Reconditioning of wells throughout the state led to a total recompletion of 230 wells. Of these, 131 were oil wells with a combined initial production of 8360 bbl., 31 were gas wells with a total initial of 211,950,000 cu. ft., and 68 were abandoned. The 46 successful wildcats opened 33 new producing areas, one of which produced from three separate horizons, and led to the development of production in new horizons in 11 old pools. While none of the 1943 discoveries have as yet developed into what might be termed major pools, the West Moore pool, in Cleveland County, and the West Edmond pool, in Oklahoma County, are the two outstanding new areas opened to production. The West Moore pool, sec. 29, 10 N., 3 W., discovered in December 1943, was completed for an initial production of 248 bbl. of oil in 3 hr. through small tubing chokes in the second Wilcox sand from 8787 to 8800 ft. One well was drilling in this area at the close of the year. The West Edmond pool, an April discovery in sec. 32, 14 N 4 W., is producing from the Hunton lime at a depth of approximately 6950 ft., the world's deepest Hunton lime pool. To the end of the year, 15 oil wells had been completed, with no gas wells and no failures. Accumulated production to Jan. I, 1944, amounted to 474,300 bbl. of 41" gravity oil. There were 29 active operations in the field at the end of the year. The West Edmond and West Moore pool discoveries established the first commercial production west of the Granite Ridge,

Jan 1, 1944

By Raymond D. Sloan

Dropping from third position among the oil-producing states of the nation in 1942, Oklahoma ranked fourth in 1943 with a total output of 121,431,ooo bbl., a decline of 11.9 per cent from the previous year's total of 137,792,000 bbl. Production ranged from a maximum of 346,900 bbl. daily in February to a low of 322,800 bbl. daily in October, and at the close of the year was averaging 330,000 bbl. daily from 52,096 wells, or an average of 6.3 bbl. per well. The state's well, average at the close of 1942 amounted to 6.7 bbl. At the turn of the year, it appeared reasonable to assume that Oklahoma's producing rate would continue its downward trend during 1944 unless reversed by greater than normal discoveries. To Jan. I, 1944, Oklahoma has produced 5,188,466,-ooo bbl. of crude oil. Development and Exploration A total of 1287 wells was drilled in 1943, representing an increase of 77 wells, or 6.4 per cent over the preceding year's total of 1210. Of the wells completed, 587 (45.6 per cent) were oil wells with an average initial production of 319 bbl.; 127 (9.9 per cent) were gas wells with an average initial of 8,639,000 cu. ft.; and 573 (44.5 per cent) were dry. A total of 333 wildcats was drilled (25.9 per cent of all wells), an increase of 13 (4.1 per cent) over the 1942 total of 320. Of the*wildcats drilled, 46 (13.8 per cent) were oil wells with an average initial production of 235 bbl.; 27 (8.1 per cent) were gas wells with an average initial of 8,249,-ooo cu. ft.; and 260 (78.1 per cent) were recorded as failures. Reconditioning of wells throughout the state led to a total recompletion of 230 wells. Of these, 131 were oil wells with a combined initial production of 8360 bbl., 31 were gas wells with a total initial of 211,950,000 cu. ft., and 68 were abandoned. The 46 successful wildcats opened 33 new producing areas, one of which produced from three separate horizons, and led to the development of production in new horizons in 11 old pools. While none of the 1943 discoveries have as yet developed into what might be termed major pools, the West Moore pool, in Cleveland County, and the West Edmond pool, in Oklahoma County, are the two outstanding new areas opened to production. The West Moore pool, sec. 29, 10 N., 3 W., discovered in December 1943, was completed for an initial production of 248 bbl. of oil in 3 hr. through small tubing chokes in the second Wilcox sand from 8787 to 8800 ft. One well was drilling in this area at the close of the year. The West Edmond pool, an April discovery in sec. 32, 14 N 4 W., is producing from the Hunton lime at a depth of approximately 6950 ft., the world's deepest Hunton lime pool. To the end of the year, 15 oil wells had been completed, with no gas wells and no failures. Accumulated production to Jan. I, 1944, amounted to 474,300 bbl. of 41" gravity oil. There were 29 active operations in the field at the end of the year. The West Edmond and West Moore pool discoveries established the first commercial production west of the Granite Ridge,

Jan 1, 1944

By Ernest F. Burchard

Fluorspar is found in most of the states from the Rocky Mountains westward, and commercial production of the mineral has been reported from Arizona, Colorado, Nevada, New Mexico, Utah and Washington. The map in Fig. 1 indicates the general distribution of many of these deposits but it is by no means complete. In the summer of 1926 the writer examined certain deposits of fluorspar in Arizona, California, Colorado, New Mexico and Washington; in November, 1927, revisited the Jamestown, Colo., district, and in earlier years examined deposits in Colorado and New Mexico. Based on notes of his own and on descriptions and other data by H. A. Aurand, H. W. Davis, R. B. Ladoo, V. C. Heikes, W. D. Johnston, Jr., and by producers of fluorspar, he prepared the following brief descriptions of deposits and estimates of reserves of fluorspar, originally for the use of the subcommittee on fluorspar of the Joint Committee on Foreign and Domestic Mining Policy and on Industrial Preparedness respectively of the Mining and Metallurgical Society of America and the American Institute of Mining and Metallurgical Engineers. Descriptions of many fluorspar deposits in various western states and districts have been published. It is not feasible to summarize this literature here, but the appended bibliography will indicate to the interested reader what papers are available. Arizona Fluorspar has been reported as occurring in Arizona in the following localities: near Duncan, Greenlee County; near Naco, Tombstone, and Paradise, Cochise County; Black Mountain, Mojave County; 25 miles southwest of Tucson, and at Helvetia and Silver Bell, Pima County; near Mammoth mine, Pinal County; in Yavapai County, 7 miles from Aguila, and in the Bradshaw Mountains; and near Dome, Yuma County. Production has come principally from the Castle Dome district, Yuma County, with minor quantities from Greenlee, Pima and Yavapai counties. The writer examined deposits in the Castle Dome district, Yuma

Jan 1, 1934

Andes Copper has an old camp and a new camp, both isolated until recent road improvements. The old camp is at Potrerillos and the new one at El Salvador, 25 road ,miles away. The company was incorporated in 1916 and the first mine, concentrator, leaching plant, smelter and town were built in the succeeding twelve years. The first blister copper was poured on January 24, 1927. Economic conditions determined the long development period but the end result was the design and construction of a mining complex that was all of a piece, unlike the piecemeal additions to El Teniente and Chuqui. The mining episode at Potrerillos came to an end in 1960 when the ore at La Mina became exhausted and the new mine, El Salvador was brought in. Both of these ore deposits come within four hpundred feet of the surface and had they been developed within the last five years might reasonably have been brought in as open pit mines. However, that is conjecture, and as it stands the operation at La Mina was so ideal for the mining method selected, blockcaving, it became a classic for the textbooks. On the other hand, El Salvador has turned out to be a blockcaving mine to test an engineer's skill. In mining the copper deposit at Indio Muerto mountain, there are ground conditions of every conceivable type. Tunneling in one section, the back can cave like sized pea gravel and only spiling can hold it; in another heading only the lifters are shot but often the rest of the round will sit down in one piece; elsewhere the bottom squeezes up and closes the drifts; and contrary to all other locations, there are sections where the block can be undercut without support. Today the scope of operations at Andes extends from mining to electrolytic copper. Ore is mined at El Salvador and the concentrator is also situated there. Concentrates pipelined 14 miles to Llanth, the water decanted, and then it is hauled by rail 40 miles and 5500 ft higher to the Potrerillos smelter and refinery. Potrerillos and El Salvador are respectively 90 and 70 miles from the port of

Jan 11, 1969

By M. Kitada, U. Kawabe, F. Ishida, T. Doi

The relations between micros tructures and critical current density in transverse magnetic field were experimentally investigated due to each transformation of the 0 to 0' + P" phases at 700' C for superconductmainly examined using replication electron microscopy. The ß' or a precipitates were found to pin down magnetic flux lines in these alloys. The effects of precipitation upon the critical current density were discussed in relation with the size, spacing, and characler of these precipitates. HIGH magnetic field superconductors, such as Nb-Zr, Nb-Ti, and Nb-Zr-Ti alloys, have been recently put to extensive practical use as winding materials for superconducting magnets.13 The critical current density of these hard superconductors under an applied magnetic field is an important characteristic for magnet materials and is very sensitive to metallurgical structure. It is generally known that the critical current density is increased by introducing dislocations and precipitates into a superconductor; that is, dislocations and precipitates are presumed to be barriers that hinder quantized flux lines from moving.4'5 Theoretical6'7 and experimental analyses of the motion of flux lines and the interaction between flux lines and various defects have already been reported by many authors. Metallographic analysis of high magnetic field superconductors such as Nb-Zr and Nb-Ti is difficult, so that no quantitative relationship between microstruc-ture and critical current density has been established yet. In this paper, the effect of precipitation on the critical current density in magnetic field was investigated for two superconducting alloys, Nb-40Zr-10Ti and Nb-5Zr-60Ti. In these alloys the resistive critical field H, at 4.2oK was about 100 kG and the critical current density Jc at 80 kG was of the order of 104 amp per sq cm.13-l5 The superconducting properties were examined in relation to the microstructural changes due to transformation of i) the ß to ß' + ß" phases at 700°C for Nb-40Zr-10Ti alloy and ii) the ß to a + ß phases at 500°C for Nb-5Zr-6OTi alloy. The effect of size, spacing, and character of precipitates on flux line pinning was in particular examined. The microstructures were studied by means of residual resistivity, microhardness, and tensile strength measurements as well as by X-ray diffraction, optical, and replication electron microscopies. I) EXPERIMENTAL PROCEDURE Pure niobium, zirconium, and titanium, in the form of rods 0.8 cm in diam, served as raw materials. Results of chemical analyses of these rods are given in Table I. Ingots of the alloys, 0.4 cm in diam and 3 cm in length, were prepared by means of levitation melting, utilizing a copper mold in an argon-gas atmosphere. Samples from the ingot then were cold-worked by grooved mill to 0.2 cm in diam, heat-treated homogeneously (in the ß phase region) for 5 hr at 1100° in a vacuum of 1 x 106 Torr, and finally cold-drawn to 0.025 cm in diam. For heat treatments, samples were wrapped in niobium foil and sealed in an argon-gas atmosphere in fused quartz capsules. Water quenching was done after each heat treatment. Subsequently H-J, were performed at 4.2° by slowly transporting the current through the samples 4 cm long, under transverse magnetic field, until the least detectable resistive terminal voltage was observed. The resistive critical field H, was taken as the field at which 100 pv appeared at 4.2°K across a sample 3 cm in length, with a current of 5 ma. The critical temperature T, was measured by means of a conventional four-probe resistivity technique and taken as the temperature at which the sample resistance reached one-half of full restoration of the normal-state resistance with a current l ma flowing through a sample 2 cm in length. Precipitates were observed by means of optical microscopy and carbon replication electron microscopy. The etching solution consisted of 5 ml HF, 10 ml H2SO4 10 ml H2O2, and 50 ml H2O, and shadowed carbon replicas were examined in a itachi HU-11 electron microscope operated at 50 kv. X-ray diffraction photographs were taken by a 11.46-cm-diam Debye-Scher-rer camera using copper Ka radiation. The micro-hardness was measured under a load of 200 g using

Jan 1, 1969

By Newell G. Alford

Forecasts of future timber consumption in soft-coal mining are handicapped by the lack of adequate experience records for estimating properly the timber requirements of the industry. Data were obtained from plants where records are kept or from operators who collected the information and to these were added composite figures for the continental United States in 1905 and 19191 and for central and western Pennsylvania and for Illinois in 1922.2 The result, representing slightly over 928,000,000 net tons, is shown in Table 1. Some of the companies furnishing data were unable to segregate the timber into classes of use but for those who did, Table 2 shows the board feet of posts and cross ban used per ton of coal mined and the percentage of the total timber consumed that was used in roof support. The wide variation in amounts of timber per ton of coal mined is the result of

Jan 1, 1924

By K. S. Lane

The problem of stability of slopes in reservoirs is one of real interest in civil engineering. The problem is whether the valley walls will remain stable or whether they are likely to slide as conditions are changed by storage of water in the reservoir. If major slides are indicated, as on the walls of relatively steep canyons, one must estimate whether they will be so located and of sufficient size as to interfere with operation of the reservoir-as by blocking the outlets, or by displacing sufficient water to over-top the dam in a huge wave. Some cases involve problems in soil mechanics for slides in earth or weaker rock; other locations need the assistance of rock mechanics for slides in harder rock. While this is not a new problem, attention has recently been focused on its importance by the hugh landslide into the Vaiont reservoir in 1963, which claimed the lives of over 2000 people and forced abandonment of the dam and powerhouse. VAIONT RESERVOIR SLIDE Fig. 1 shows Vaiont Dam in Italy which is a double curvature arch, 875 ft high, located on a tributary of the Piave River, north and west of Venice. When completed in 1960 it was the highest arch dam in the world. In 1960 a sizable landslide (some 700,000 cu yd) occurred on the left abutment a short distance above the dam. Following this, the reservoir was held down for construction of a by-pass tunnel through the right valley wall to insure connection with the upper end of the reservoir in event of further slides. In October 1963 a giant landslide occurred on the left valley wall, over a width of some 14 miles (see Fig. 2). Over 300 million cu yd slid into the reservoir, displacing the water and forming a hige wave 700 ft above the top of the dam as it hit the opposite, or right, wall of the valley. The wave then passed some 500 ft over top of the dam, followed down the tortuous winding canyon and debouched into the

Jan 1, 1967

By W. D. Keller

THE high-alumina clays of Missouri are interesting for several reasons. They are the only sedimentary deposits in North America of first grade (over 70 pct A1,0,) diaspore and boehmite sufficiently large to be mined commercially. Mineralogically, they are composed of diaspore and boehmite in intimate coexistence, but gibbsite, the common hydrated alumina mineral in bauxite and laterite, is absent, or is exceedingly scanty if present.* Therefore, the Missouri high-alumina clays do not represent typical laterization. The physical chemistry leading to their mineral genesis, and the geolbgical setting for their formation, present important problems for scientific study. The origin of the Missouri high-alumina clays has been discussed in earlier reports by Allen1 (1935) and McQueen 8, 9 (1929, 1943). These investigations were made under difficult conditions, however, because no diaspore deposit had been opened where a Paleozoic (Pennsylvanian) rock cover lay undisturbed over the high-alumina clay. The relationship of the clay to only the underlying rocks could actually be observed. Lacking the guidance of critical postdepositional geologic evidence, undue and erroneous emphasis was placed on the postdepositional leaching of the deposits in the theories on the origin of diaspore and boehmite from clay (hydrous aluminosilicates) . With new geologic evidence at hand, a clearer picture can be made for the origin of the Missouri high-alumina deposits. In this paper the geology of a diaspore deposit whose original Paleozoic cover had not been eroded will be described and interpreted genetically. The close relationship of boehmite and diaspore (also with kaolinite and a chloritic mineral), will be established. A theory of origin for the high-alumina clays, consistent with the new data, will be postulated.

Jan 1, 1952

By E. P. Polushkin

This work has for its purpose the establishment of a new method for determining the structural composition of alloys. The area occupied by a constituent on a few representative photomicrographs of the alloy is measured, by a planimeter, especially designed for metallographic work, and the volume and proportional weight of the constituent calculated. Experiments have shown that the results are accurate enough to justify the application of the method to many problems in metallographic research instead of chemical analysis. The advantage of the method is the possibility of determining the amount of the constituents without separating them from the alloy; their composition may also be determined if the ultimate chemical analysis of the alloy is known. Suppose Fig. 1 represents a part of a photomicrograph on which the total area of the black figures is to be found. By a system of parallel lines drawn short equal distances apart all figures may be divided into trapezoids. As the area of a trapezoid is equal to its median multiplied by its altitude, the relation between the total areas of the black and the white figures comprised within each strip is equal to the relation between the sums of medians for these figures respectively. This is also true for the whole area of the photomicrograph. Therefore, to determine the total areas of the black and white figures we must first find the proportion between the sums of the medians and then divide the area of the whole photomicrograph in the same proportion.

Jan 1, 1925

J. J. RUTLEDGE,* McAlester, Okla. (written discussiont).-Research work has often a more immediate and practical application to the in-dustries than even the investigators themselves realize, but coal mining has not attracted the investigator, except in so far as the mine-accident prevention work and fuel investigations are concerned. In future, the coal geologist will study the subsurface geology of the various coal seams as the petroleum geologist now studies the oil sands, and from the results of these studies the coal operator will be able to locate his shafts to the best possible advantage and to avoid faults that would interfere with underground work. There would have been many thousands of dollars saved, and perhaps some reputations, if a good stratigrapher. had been called into consultation in the southern part of Somerset County, Pa., where a local seam of coal, quite thick, was mistaken for the Pittsburgh seam, which, if ever present at that point, had long since been eroded. Why will the Quemanhoming coal carry more sulfur without injuring the grate bars than George's Creek Big Vein? Only the investigator can answer and yet the fact that the above is true means a greater price for the thinner coal. The owner of the land in Oklahoma receives one-fourth of the cotton crop produced by the tenant who farms his land and one-third of the

Jan 11, 1919

By J. H. Brophy, S. J. Michalik

A constitution diagram for the system Mo-Ir has been determined. The maximum solubility of iridium in molybdenum is 16 at. pct at 2110ºC and decreases to less than 5 at. pct at 1500°C. The solubility of molybdenum in iridium is 22 at. pct. Three intermediate phases appear in the system: 8 MoJr, having the p-tungsten structure; a phase, a cornplex tetragonal structure; and the hcp ? phase. Metallography, melting point determinations, X-ray diffraction and fluorescence, and electron micro-probe unalyses were employed in establishing the diagram. PREVIOUS to the present investigation, the intermediate phases in the Mo-Ir system were identified, but no detailed account of the phase diagram has been reported in the literature. Raub1 investigated alloys of Mo-Ir over an extensive range of composition between the temperatures of 800º and 1600°C. The in-termetallic compound MosIr was found to exist with nearly pure molybdenum, as the solubility of iridium in molybdenum was not detectable parametrically in this temperature range. MO3Ir was found to be iso-morphic with a ß-tungsten type structure, having a parameter of 4.959Å. An intermediate hcp phase, designated as the ? phase, ranged in composition from 52 to 78.5 at. pct at 800ºC, and from 41 to 78.5 at. pct Ir at 1200°C. Parameters noted for the ? phase were as follows: at 42.7 at. pct Ir, a = 2.771i0, c = 4.4366, c/a = 1.601; at 78.5 at. pct Ir, a = 2.736A, c = 4.378A, c/a = 1.600. Molybdenum was found to be soluble in iridium up to 16.5 at. pct Mo (83.5 at. pct Irj, with the parameter of iridium increasing to 3.845A at the solubility limit. Knapton,2 who investigated alloys between 15 and 85 at. pct Ir, essentially agreed with Raub's data, but, in addition, found a a phase in as-melted alloys near 25 at. pcto Ir. The oaphase lattice parameters were a = 9.64Å, c = 4.96Å, c/a = 0.515. The a phase was replaced by the 8 -tungsten phase on annealing at 1600°C. Knapton concluded that the a was stable only at elevated temperatures, and placed the composition of the a phase at approximately 30 at. pct Ir. The intermetallic compound Mo3Ir, with a lattice parameter of 4.965A, was included among the 8-tungsten structures reported by ~eller.' Matthias and Corenzwit,4 and Bucke15 studied the superconducting nature of MosIr, and reported a superconducting transition temperature of 8.$K. The present investigation describes the phase relationships in the Mo-Ir alloy system determined by melting point measurements, X-ray diffraction and fluorescence, and metallography. EXPERIMENTAL PROCEDURES Alloys for the determination of the phase diagram were prepared from powders. Commercial 99.9 pct Mo from Fansteel Metallurgical Corp. and 99.9 pct Ir powder from J. Bishop and Co. Platinum Works were used. The powders were weighed to nominal compositions, mixed, and then pressed, without binder, into compacts weighing 4 to 6 g. These were presintered in uacuo between 1200' and 1400°C for 1 hr, to reduce the degree of spattering during subsequent arc-melting. The compacts were arc-melted in a nonconsumable tungsten electrode furnace six times on alternate sides on a water-cooled copper hearth in an atmosphere of zirconium-getter ed argon at 500 mm of mercury pressure. In almost all cases, this procedure yielded buttons of satisfactory homogeneity. The composition of all melted buttons were confirmed by X-ray fluorescent analysis using the experimentally determined ratio of the iridium La1 line intensity to that of the molybdenum Ka1 line as a function of composition. In this determination four alloys analyzed by wet chemical methods were used as standards. An uncertainty range of ±1 at. pct has been attributed to all indicated compositions. All heat treatments and solidus measurements were carried out in tantalum resistance heating elements in vacuum conditions of 10-4 to 10-5 mm of mercury. A detailed account of this procedure has been reported by Schwarzkopf and Brophy.8 In the heat treatment and solidus measurements of iridium-rich alloys (50 at. pct Ir or greater), a tungsten lining was inserted into the tantalum resistance heating element because of a eutectic reaction which occurs between iridium and tantalum at 1948ºc.7 Heat treatments and solidus measurements carried out at compositions less than 40 at. pct Ir both with and without tungsten linings within the resistance

Jan 1, 1963

By R. T. Gallagher, C. G. Brennecke

This paper is the result of a research program entered into cooperatively by the General Reinsurance Corporation and Lehigh University in January 1944. The research program was instituted to find a more positive method to determine the presence of hazardous roof conditions in mining operations. The co-authors, together with Mr. R. D. Currie, Engineer for the General Reinsurance Corporation, started working on the project in January 1944, first undertaking a library search; second, a preliminary study based on some existing equipment; third, the design of new and more suitable equipment; and finally, the field testing of equipment and methods. PURPOSE Any study of the accident statistics of mining operations will disclose the rather startling fact that approximately 50 to 60 per cent of all fatal underground accidents in the anthracite and bituminous mines are caused by falls of roof and coal, the metal and nonmetal mines showing only a slightly smaller percentage. Advancements in safety engineering have produced definite results in the decrease of accidents due to blasting, haulage, electricity, and explosions but no such decrease is shown in those caused by falls

Jan 1, 1946

By J. F. Wolff, Anson A. Betts

The following correspondence relating to a paper bearing the above title, presented by J. F. Wolff, at the New York meeting in February, 1917, and published in the Transactions, Volume LVI, page 142, has passed between the author of the paper, and Mr. Anson G. Betts, and is interesting, although it was received much too late for incorporation in its proper place in Volume LVI. Anson G. Betts, Asheville, N. C.—1. I should like to ask Mr. Wolff if he finds from analysis of the iron formation and of the iron ore, and from the relative amounts of each in each unit area of the formation, unleached and after leaching, that the iron remains entirely insoluble and the total quantity still remains present; or whether he finds that some of the iron is removed, or possibly even added by deposition from the water passing through the formation. 2. The water that passed into the iron formation had to go somewhere; was it absorbed by underlying formations through hydration, or, after passing through the ore formation, did it come to the surface in springs at a lower elevation, or how did it escape from the ground? 3. I should like to ask Mr. Wolff whether he finds that the iron formation in the sedimentary series does not come next to the quartzites and generally between the quartzites and slates. J. I?. Wolff, Duluth, Minn.—1. In common with others, you appear to have some hesitancy in accepting the fact of the removal, by solution, of the enormous quantity of silica which has been leached out of portions of the Biwabik iron formation, thus forming orebodies of merchantable iron ore. I believe that even Dr. Waldemar Lindgren once hesitated to accept this fact. However, the evidence is so simple and absolutely conclusive that the fact is established beyond all question. At the contact of orebodies with their rock walls, the bands of iron ore in the orebody can be seen in contact with the corresponding bands of original iron oxide in the rock wall, and the chert layers in the rock wall can be seen to give place to fine granular material (fine silica and iron oxide) and pore space. This is especially noticeable where slumping at the rock walls has not been so great as to displace the layers in the orebody from their contact with their corresponding layers in the rock wall. Although complete analyses of the entire original rocks in the iron series have not been made in any place, to my knowledge, from the best data at hand as to the average analysis of the Biwabik series and the

Jan 1, 1920

By I. Javandel, P. A. Witherspoon

The finite element method was originally developed in the aircraft industry to handle problems of stress distribution in complex airframe configurations. This paper describes how the method can be extended to problems of transient flow in porous media. In this approach, the continuum is replaced by a system of finite elements. By employing the variational principle, one can obtain time dependent solutions for the potential at every point in the system by minimizing a potential energy functional. The theory of the method is reviewed. To demonstrate its validity, nonsteady-state results obtained by the finite clement method are compared with those of typical boundary value problems for which rigorous analytical solutions are available. To demonstrate the power of this approach, solutions for the more complex problem of transient flow in layered systems with crossflow are also presented. The generality of this approach with respect to arbitrary boundary conditions and changes in rock properties provides a new method of handling problems of fluid flow in complex systems. INTRODUCTION Problems of transient flow in porous media often can be handled by the methods of analytical mathematics as long as the geometry or properties of the flow system do not become too complex. When the analytical approach becomes intractable, it is customary to resort to numerical methods, and a great variety of problems have been handled in this manner. One such method relies on the finite difference approach wherein the system is divided into a network of elements, and a finite difference equation for the flow into and out of each element is developed. The solution of the resulting set of equations usually requires a high speed computer. When heterogeneous systems of arbitrary geometry must be considered, however, this approach is sometimes difficult to apply and may require large amounts of computer time. The finite element method is a new approach that avoids these difficulties. It was developed originally in the aircraft industry to provide a refined solution for stress distributions in extremely complex airframe configurations. 27 Clough has recently reviewed the application of the finite element method in the field of structural mechanics.6 The technique has been applied successfully in the stress analysis of many complex structures.l, 27, 28 Recognition that this procedure can be interpreted in terms of variational procedures involving minimizing a potential energy functional7 leads naturally to its extension to other boundary value problems. In the field of heat flow, there recently have been introduced several approximate methods of solution that are based on variational principles.2-4, 17 By employing the variational principle in conjunction with the finite element idealization, a powerful solution technique is now available for determining the potential distribution within complex bodies of arbitrary geometry. In the finite element approximation of solids, the continuum is replaced by a system of elements. An approximate solution for the potential field within each element is assumed, and flux equilibrium equations are developed at a discrete number of points within the network of finite elements. For the case of steady-state heat flow, the technique is completely described by Zienkiewicz and Cheung.33 Since the flow of fluids in porous media is analogous to the flow of heat, Zienkiewicz et al. have employed the finite element method in obtaining steady-state solutions to heterogeneous and anisotropic seepage problems. 34 Taylor and Brown have used this method to investigate steady-state flow problems involving a free surface.25 The work of Gurtin has been instrumental in laying the groundwork for the application of finite element methods to linear initial-value problems.12 As a result, Wilson and Nickell have recently

Jan 1, 1969

The Molycorp operation at Mountain Pass, California, is unique in that it is the only place in the world where bastnasite is mined. The orebody is a metamorphic carbonatite; the mineral of importance is bastnasite, a fluocarbonate containing principally cerium, lanthanum, neodymium, and praseodymium, with small amounts of samarium, gadolinium, and europium. In addition, appreciable quantities of barite, calcite, and strontianite are present. Molycorp had mined and processed the bastnasite ore since the early 1950s at a rate of about 100 tpd by a unique hot flotation process in a plant originally used for cyanidation of gold ore. The concentrate was primarily used in high quality glass polishing, lighter flints, ceramics, and in specialty steel making. Then in the early 1960s, Molycorp and the Colorado School of Mines Research Foundation developed a solvent extraction process to recover europium from the bulk rare earth concentrates. In 1965 a new SX plant was constructed to produce this material for use as a red phosphor in color television tubes. Because of the demand for this material, a new 500 tpd concentrator was designed and constructed in 9 ½ months. Then, because of a sharply increased demand for europium, the plant was expanded to 1200 tpd only four months after completion of the original construction. The crushing section of the new plant was designed similarly to those portable units used in road construction and arrived on the site in ten major pieces. Foundations were concrete piers; and after their completion, the entire crushing plant composed of primary and secondary crushers, conveyors, and a screen was erected in fourteen days by a crew of ten men assisted by a mobile crane. Pit-run ore is loaded into 35-ton trucks by a 7 yd (5.4 cu m) loader, trans- ported to .the crushing plant, and dumped into the 65 -ton concrete pocket. A 42 in. by 20 ft (1.07 m by 6. 1 m) apron feeder feeds ore to the 30 in. by 42 in. (760 rnrn by 1070 mm) single toggle jaw crusher. Crushed ore is trans- ferred by a scissors conveyor to a 5 ft by 14 ft (1.52 m by 4. 27 m) double- deck screen which produces a final ¾ in. (19 rnrn) product with the oversize being treated in a 4 ¼ ft (1. 3 m) standard cone crusher. Cone crusher product is returned to the first scissors conveyor to join the primary crusher product. Dust collection is by a wet scrubber, and an operator's control room is located to overlook the primary. The entire crushing is in the open, and a 30-ton mobile crane is used for maintenance. Molycorp’s two-stage crushing plant is an excellent example of functional design for a small mining and milling operation.

Jan 1, 1978

Discussion of the paper of J. K. FURST, presented at the Pittsburgh meeting, October, 1914, and printed in" Bulletin No. 94, October, 1914, pp. 2493 to 2514. W..McA. JOHNSON, New York, N. Y.-On discussing this paper I am open to the criticism of "bringing coals to Newcastle," as I, a zinc man, am bringing new ideas on steel to Pittsburgh. But still the view of an outsider can be valuable to the insider. Any multistage process, where each apparatus operates on its particular part of the work at a high efficiency, constitutes an advance in the state of art. But in multiplicity there can be complication and ensuing loss and inefficiency. The duplex steel process is not the pronounced success which was predicted for it by its adherents, for several of such plants have reverted to plain open-hearth methods. If we regard broadly refining processes, such as the Bessemer, open-hearth, puddling, copper refining, lead cupelling, nickel refining, we find that in general refining processes are intermittent and 'concentration processes are continuous. (This generalization I believe to be original with me; it was communicated to Dr. E. F. Roeber, editor, and appeared as an editorial in Metallurgical and Chemical Engineering, March, 1905.) Where we desire primarily quality in a metallurgical operation we must put a batch of metal in the furnace, work on it until we get it to the required purity, test it, and take it out; whereas, if we desire primarily quantity we shove ore into a furnace and smelt it as fast as possible, allowing conditions to make a non-uniform product provided only we get tonnage. From general commercial principles, I believe that the weak point of the duplex process is that the operation is not a money maker unless the plant is kept at. 90 to 95 per cent. of its rated capacity, or unless the Bessemerizing is done so often that it is practically continuous. For in some manner the operation should be made continuous and the control on the tonnage should be commercially flexible. The commercial rigidity of having to control purity exactly increases operating costs without a corresponding gain. Conversely, the chief reason for failure of "steel from ore direct" is that it makes a final operation continuous, which should be naturally intermittent.

Jan 4, 1915

GENERAL GEOLOGICAL DESCRIPTION The uranium mineral appraisal herein described was made for an ore deposit in New Mexico. The uranium mineralization occurs as roughly tabular to lens-shaped deposits of varying thickness within the sandstone of the Jackpile formation of Jurassic age. The mineralization occurs at several horizons within the Jackpile formation, but is not always confined to specific beds. It often transgresses across stratigraphic layers, as demonstrated when attempting correlation of uranium gamma anomalies between adjacent drill holes. Preferred mineral trends have been established in some parts of the deposit, but are not always predictable when attempting to extrapolate beyond the zones defined by drill hole sampling. MANAGEMENT OF DRILL HOLE SAMPLE DATA All of the drill hole sample data used in the appraisal were obtained from interpretation of gamma-ray logs. A brief description of gamma-ray log sampling is given in Chapter 2. Two preliminary steps are involved in preparing gamma-ray logs into sample data normally acceptable for computer manipulation. 1) The gamma analog trace produced by the downhole probe must be digitized, i.e., counts-per-second (CPS) are recorded for each 0.15 m (1/2-ft) interval across the gamma-ray anomaly. The work is usually done on a "digitizer" while following the analog trace with an electronic stylus on a special tablet or table. The other alternative is to do the work manually. Some of the newest downhole logging equipment produces a magnetic tape output which can be read by a computer. 2) The gamma-ray CPS values must then be converted to equivalent U308 assay values, taking into consideration all appropriate correction factors. The US Atomic Energy Commission, now part of the Department of Energy, developed the theory and algorithm for this conversion in the 1960's, and though the work can be done manually, it is best done with the GAMRED (gamma-reduction) computer program. Fig. 14-1 illustrates a typical analog trace produced by the probe instrumentation, including gamma-ray trace (left), self-potential electric log (center), and resistivity log (right). Fig. 14-2 shows a form of the computer output after the analog data has been digitized to 0.15-m (1h-ft) intervals and converted to percentage U308 values for the same hole. The U308 grade bar graph on the right permits rapid visual inspection of anomalous values by depth and elevation. The converted U308 sample data were next processed by the SURVEY program that assigned to each assay interval [0. 15-m (1h-ft)] an X Y Z coordinate, taking into account all deviations indicated from downhole survey information. The output file of the SURVEY program was listed on the line printer for examination by project geologists, and also became the main input file for the URAN/ COMP compositing program, which is designed to group individual 0.15-m (/-ft) U308 sample values into larger intervals representing discrete anomalous zones according to a series of specified parameters entered into the program by the user. Composite U308 intervals were computed by the URAN/COMP computer program, the logic of which may be briefly described as follows: Step 1 The program searches for the highest U308 value in the hole and builds a composite by adding the highest grade interval on either side so long as the added value is greater than a minimum acceptable grade, and the total composite, after addition, meets minimum GT (grade times thickness) constraints. Step 2 The program loops back to find the next highest assay value in the hole not already included into a composite, until all anomalies above minimum cutoff grade are composited. Step 3 Individual composites are combined if they are closer than a specified minimum waste thickness, and the resultant composite grade still meets GT minimums.

Jan 1, 1980