Search Documents

By K. P. Chong

Introduction One of the requirements of processing oil shale or other energy bearing rocks is to optimize particle sizes and permeability distributions in fragmentations as indicated by Hommert (1984). Basic to the understanding and planning of in situ fragmentation and ex situ mining of oil shale are the mechanical properties. During the past six years, an innovative and unique program was established by Chong et al. (1979, 1980a, 1980b, 1982a, 1982b) that developed an efficient methodology for standardized and simplified mechanical testing of the western oil shale. The experiments include precise, representative, and duplicable sample preparation; uniaxial static compression testing; "modified" split cylinder testing; uniaxial creep and relaxation testing under extended periods of time; dynamic testing with varying strain rates; and 3-D constitutive relationships. However, as far as the fracture mechanics is concerned, as Edl (1980) pointed out, there is still a lack of understanding "of the fundamental explosive rock breakage mechanisms," which "has necessitated extensive reliance on very costly empirical approaches." Fracture mechanics of rocks and oil shale (Costin, 1981; Schmidt, 1977; Abou-Sayed, 1977; and Barker, 1977) has been based on conventional fracture mechanics using regular notched samples with limited variations of oil yields and assuming the material to be isotropic and elastic (Kobayashi, 1975; Caddell, 1980). A cylindrical double cantilever beam (DCB) specimen with a "V" slot, known as a short rod specimen, has been used by Barker (1977) to determine fracture toughness of rock materials. The inherent geometric stability of the reinforced DCB specimen makes it suitable to be used with all brittle materials. Due to its remarkable stability for the initial crack growth, the DCB specimen can be used for dynamic fracture toughness testing as well. This specimen is more suitable for the evaluation of fracture toughness at high strain rates than most other fracture specimens. However, Barker's DCB specimen is not very well adaptable for short cores or layered rocks since the specimen contains numerous layers (say in a 100-mm (4-in.) long specimen), and the rock properties change from layer to layer. Schmidt (1977) studied the fracture mechanics of oil shale with two oil yields, using notched beams. Using several independent established testing methods, Costin (1981) pioneered the investigation of the static

Jan 1, 1986

By Sylvain J. Pirson

The main value of earth magnetic measurements, outside of certain mining problems, resides in the study of deeply buried tectonic phenomena related to regional and local geology. Magnetic surveys are a necessary complement of gravimetric measurements, especially of pendulum surveys. To date, magnetometer prospecting has been used chiefly in the study of sedimentary basins where petroleum structures are associated with the uplifted basement rocks. There are, in the literature, innumerable articles dealing with such surveys as applied to oil geology but few treat of broad geological features related to regional magnetic disturbances of the earth field. An important piece of coordination work has been made by Jean Jungl for the magnetic and gravimetric measurements made in France and their geologic significance. A similar attempt at correlation of the known geology with the anomalies of the vertical component of the earth magnetic field has been made for the United States by George B. Somers2. Taking the magnetic vector as a whole, W. P. Jenny3 made a coordination of magnetism and geology for the main producing oil states of the United States. A more detailed study along the same lines is published by A. Van Weelden4 for southern Oklahoma and northern Texas; in this work magnetic and gravimetric measurements taken at stations as close as one mile apart are compiled and compared to the regional geology of the Ouachita-Amarillo uplifted area. From the literature mentioned, it is evident that reliable interpretation of magnetic' anomalies can be arrived at only when the magnetic stations are numerous and cover the area in a close net of measurements, therefore the works of Somers and Jenny, based on sparsely distributed Government measurements, can be regarded only as preliminary programs indicating lines along which further work should be done, whereas the coordination made by Van Weelden is an example of the contribution to the knowledge of regional geology that can be arrived at by the use of applied geophysics. With the hope that further systematic magnetic measurements will be carried on to solve regional and local geological problems, the author

Jan 1, 1940

By Sylvain J. Pirson

The main value of earth magnetic measurements, outside of certain mining problems, resides in the study of deeply buried tectonic phenomena related to regional and local geology. Magnetic surveys are a necessary complement of gravimetric measurements, especially of pendulum surveys. To date, magnetometer prospecting has been used chiefly in the study of sedimentary basins where petroleum structures are associated with the uplifted basement rocks. There are, in the literature, innumerable articles dealing with such surveys as applied to oil geology but few treat of broad geological features related to regional magnetic disturbances of the earth field. An important piece of coordination work has been made by Jean Jungl for the magnetic and gravimetric measurements made in France and their geologic significance. A similar attempt at correlation of the known geology with the anomalies of the vertical component of the earth magnetic field has been made for the United States by George B. Somers2. Taking the magnetic vector as a whole, W. P. Jenny3 made a coordination of magnetism and geology for the main producing oil states of the United States. A more detailed study along the same lines is published by A. Van Weelden4 for southern Oklahoma and northern Texas; in this work magnetic and gravimetric measurements taken at stations as close as one mile apart are compiled and compared to the regional geology of the Ouachita-Amarillo uplifted area. From the literature mentioned, it is evident that reliable interpretation of magnetic' anomalies can be arrived at only when the magnetic stations are numerous and cover the area in a close net of measurements, therefore the works of Somers and Jenny, based on sparsely distributed Government measurements, can be regarded only as preliminary programs indicating lines along which further work should be done, whereas the coordination made by Van Weelden is an example of the contribution to the knowledge of regional geology that can be arrived at by the use of applied geophysics. With the hope that further systematic magnetic measurements will be carried on to solve regional and local geological problems, the author

Jan 1, 1940

By Lyall, Zickrick

As a result of the studies on recrystallization and crystal growth made in this laboratory, certain theories have been developed. These are expressed briefly in a paper by Dean and Hudson.' One of the principal points brought out in that paper is that in the deformation of a crystal, the energy supplied is distributed to the atoms of the lattice, probably by the forced formation of molecules. It is found that a Maxwellian distribution of the energy among these atoms will account for the grain growth at various temperatures. According to such a distribution the number of atoms with energy above a certain critical value, E, necessary for recrystallization at the absolute temperature T is given by n = Ne-E/kT where N is the total number of atoms. It is apparent that if this line of reasoning is correct, a metal which has been cold-worked and reheated to a temperature below that of complete annealing will have the atoms with the higher energy recrystallized, that is, reduced to normal energy and there will remain only atoms below a certain energy. If this metal is again cold-worked the peak in the number-energy distribution curve will, as compaied with its position after the first cold-working, be displaced toward the regions of lower energies, that is, the temperature of recrystallization will be higher. By a repetition of this process the position of this maximum and hence the recrystallization temperature of the metal could be raised considerably. In order to check this theory, experiments have been made on copper wire. The wire was drawn from 1/4-in. rod to 22 B & S gage and then sample lots were annealed at 400 and 220° C., respectively. The wire annealed at 400° C. gave an elongation of 34 per cent., whereas that annealed at 220° C. gave only 23 per cent. These wires were then drawn by identical practice to 34 B & S gage and the elongation determined after an anneal of 3 min. in an oil bath held at various temperatures. The figures obtained have been plotted in Fig. 1. It will be seen that the

Jan 1, 1927

Jan 1, 1918

By James Humes

The active mines in the Park City district at the present time are the Silver King Coalition, Daly-Judge, Daly West, and Silver King Consolidated. Several other companies, such as the Daly, American Flag, Ontario, etc., are doing considerable development work. In the Silver King Coalition mines the ore is a replacement of a dark siliceous limestone bed, varying in .thickness from 18 in. to several feet. In places the ore has reached a thickness of 25 ft. This limestone bed lies within 100 ft. of the underlying Weber quartzite. There are other lime beds, similar in appearance to this one, in the Park City formation, which is approximately 700 ft. thick; but not one of them has been found to contain any traces of ore. Directly under and in contact with the ore-bearing bed is another, composed of gray lime well studded with dark concretionary nodules; and this one is an unfailing indication of the proximity of the ore-bearing bed. These ore deposits make out from or have connection with some one of the ore-bearing fissures, which were undoubtedly the channels for the circulation of mineral-bearing solutions. It is therefore proper to run prospecting drifts in the fissures, although they seldom contain much ore. As a general rule, drifting in the fissures is not costly. Mining and mucking cost from $2.50 to $4 per foot, and very little timber is required. There are instances, as in the Daly fissure in the Daly-Judge mine, where the expense of keeping drifts open in the fissure is so great that it has proved economical to make the drifts in the foot-wall rock and run crosscuts into the fissure at short intervals. In the Park City mines it is not easy to determine beforehand the best method fir extracting the ore from a newly discovered ore shoot in the bedded deposits. While we may get one dimension from the drift run in the fissure, that will not give us a correct idea as to the other dimensions of the orebody. The fissures here referred to have a N. 35" E.

Jan 1, 1915

By Arthur Young

UNEMPLOYMENT no longer finds its cure in pros-perity. Not only is there surplus labor in over-developed industries -like coal -mining, but more and more man, power is being released by technical im-provements in production. A new problem in industry has arisen: What is to be done with the labor dis-pensed with by better methods and more highly de-veloped equipment? Are luxury industries the logical outlet for our new unemployed? There has been a marked decline in employment in the manufacturing industries during 1927. Its extent is shown by the Bureau of Labor Statistics index, which receded from a high of 91.4 in March to 87.3 in October, with an estimated figure of approximately 85 in De-cember. This was a drop between the high and low points in the year of about 7 per cent, which means roughly that at the close of 1927 there were approxi-mately 600,000 fewer persons employed in manufac-turing industries than in March -of 1927, and upward of 400,000 less than in December, 1926. Does this de-cline reflect a swing toward industrial depression? Paradoxically it does not; the cause of unemployment at this time does not lie in a lack of prosperity, but rather is largely traceable to prosperity. Capital has been abundant and has gone back into production in the form of great increases in mechanization and new processing. Management is more than ever on the alert to improve methods, as well as to cut costs through reduction of personnel. Properly applied incentives and employee cooperation also have increased produc-tion per man. A new phenomenon in the industrial world-technological unemployment-is the result. Of course, there are added to those unemployed be-cause of the reasons just considered those affected by the coal strike, the period of shutdown at the Ford plants, and the reduction in expenditures by railroads and public utilities. This whole situation suggests that the problem of unemployment is not entirely solved by ironing out seasonal variations or by achieving business prosperity.

Jan 1, 1928

By P. Barnes

It may he of interest, and perhaps of inzportance, to the members of the Institute that specific mention should be made in detail of the great value of this method of copying or photographing all kinds of tracings." Several samples are laid upon the table which may serve as illustrations of the results obtained. Some of these show slight imperfections, depending upon the character of the tracing, and upon the length of the exposure to the light, but it may be clearly seen that even a faint copy would be quite available for actual use. The process is believed to be of French origin, and has been used for many years. Special attention seems to have been directed to it recently, and its great value to engineers appears likely to be fully recognized. The manipulations required are of the simplest possible kind, and are entirely within the skill and comprehension of any office boy who can be trusted to copy a letter in an ordinary press. These particulars may be summarized somewhat thus: 1. Provide a flat board as large as the tracing which is to be copied. 2. Lay on this hoard two or three thicknesses of common blanket, or its equivalent, to give a slightly yielding backing for the paper. 3. Lay on the blanket the prepared paper with the sensitive side uppermost. 4. Lay on this paper the tracing, smoothing it out as perfectly as possible so as to insure a perfect contact with the paper. 5. Lay on the tracing a plate of clear glass, which should be heavy enough to press the tracing close down upon the paper. Ordinary plate-glass of 3/8" thickness is quite sufficient. 6. Expose the whole to a clear sunlight, by pushing it out on a shelf from an ordinary window, or in any other convenient way, for six to ten minutes. If a clear skylight only can be had, the exposure must be continued for thirty or forty-five minutes, and under a cloudy sky, sixty to ninety minutes may be needed.

Jan 1, 1879

By David N. French

In a recent paper, Miyoshi, Hara, and sugimotoL have shown that hardness increases and crack resistance decreases with polishing time in tungsten car-bide-cobalt alloys. They attribute the changes in hardness and crack resistance to cold working in these alloys. More recently Exner2 explains the decrease in crack resistance with the amount of material removed (polishing time) by suggesting that polishing removes a high compressive residual surface stress due to the initial grinding operation. He cites previous work on steel to show grinding can induce surface compressive stresses but offers no direct experimental measurements to support this in cemented tungsten carbides. In recent work we have observed changes in residual stress in the W C phase as measured by X-ray diffraction techniques with changes in polishing conditions.3 As a result of the work of Miyoshi et al.,L a brief study was undertaken to investigate the effects of polishing and grinding on the residual stress in the WC phase and have been reported.4 A single composition of tungsten carbide —10 wt pct Co was used. Two initial conditions were studied: an annealed condition with about -30,000 psi residual stress from the differences in thermal coefficients of expansion of WC and cobalt and, on the same specimen, a surface ground with a 150 grit diamond wheel. Stress was measured in the WC phase using X-ray diffractometry as a function of the amount of material removed by metallographic polishing with 6 diamond paste. The results are shown in Fig. 1. Two things are noted, 1) polishing with 6 p diamond paste has little effect on the annealed sample and 2) the magnitude of the grinding stress is markedly reduced as material is removed. By the time 0.1 mil is removed the surface has a metallographic polish satisfactory for light microscopy examination. Thus the surface, even though polished, can still retain most of the stress due to grinding. Since WC is itself slightly ductile, it seems reasonable that high compressive stresses can be generated in the surface by the plastic deformation accompanying grinding. Exner2 suggests, by analogy with steel, that as a result of grinding both WC and cobalt in the

Jan 1, 1970

By James Douglas

An address before the Meeting of the New York Section, Nov. 4, 1914. As life advances one is inclined to look backward instead of forward, and the vista over which my memory carries me has been filled with such a shifting panorama of changes in metallurgy that the whole practice of the art seems to have been re-created. The first cupola furnace that I saw in operation was at one of the group of mines at Capelton, Quebec, from which the Nichols company still draws some of its sulphur supply. At that time it was operated by a Hartford, Conn., company, under a General Adams. When its small brick furnaces made a campaign of a week and smelted 10 tons a day, the feat redounded to the credit of the operator. The introduction of the water-jacketed cupola dates forward to the next decade. I was using one in Pennsylvania, making copper matte, to the horror of a noted metallurgist, who could not conceive it possible that you. could bring fused sulphides in contact with steel without rapid corrosion. In our ignorance we were doing what seemed to be an impossibility, and it is just that recklessness and disregard for precedent which has characterized so much of the work of American metallurgists, and carried us forward at such headlong speed. Once the water jacket was accepted as the type of the. copper cupola, its almost unlimited expansion in length, but not in width, was a matter of convenience rather than of skill. In Butte the cupolas have been enlarged by adding furnace to furnace. The first reverberatories which I saw in operation were those in Professor Hill's Black Hawk establishment, where the concentrates from the Gilpin County gold mills were run down into matte for separation in England. Sixty dollars per ton was the usual deduction in those days before gold and silver was paid for. Smelting was done with wood as fuel, and the capacity of the furnace was about 10 tons per diem. Shortly after this Professor Hill formed an alliance with Richard Pearce, who was running what, if I recollect aright, was called the Swansea Works, at the bend of the river approaching Georgetown.

Jan 4, 1915

In reply to inquiries and comments which have reached me since the publication of this paper, and in explanation of some seeming discrepancies between my statements in the text concerning the amount of displacement of the faults, on one hand, and certain figures in the plates on the other hand, I give here, with some additional remarks, my measurements of the displacements in the different sections, which it originally seemed unnecessary to print : By displacement, I mean neither the throw, i.e., the vertical distance apart of the two edges of a faulted bed (what Mr.

Jan 1, 1896

By R. R. Templeton

THE year 1924 was particularly notable in the petroleum industry of California as it was a period in which extensive town-lot drilling, with attendant overproduction and allied problems, virtually ceased and the industry returned to a nearly normal condition. Nearly all major field operations were conducted by large operating and marketing companies; in contrast to 1922 and 1923 field operations, when small promotion companies set the pace and forced the large companies to follow. The outstanding features of petroleum development were: 1. The three major fields of 1923, namely Huntington Beach, Long Beach, and Santa Fe Springs, declined from a production of 13,042,939 bbl., in January, to 6,764,417 bbl., in December, a drop of nearly 52 per cent: During this period, Huntington Beach declined 35 per cent., Long Beach 42 per cent., and Santa Fe Springs 63 per cent. 2. Methods of pumping deep wells were improved in some particulars; this contributed toward sustaining the productions of these three famous fields above what was predicted. 3. Of the fields producing previous to 1924, only three increased in production to any appreciable degree, during the year, as the result of bringing in new wells. These fields are Dominguez, Torrance, and Wheeler Ridge. Dominguez, discovered in September, 1923, produced 56,851 bbl. in January and increased regularly to a production of 1,641,042 bbl. in December. Torrance increased from a production of 972,261 bbl. in January, to 1,783,670 bbl., in May, and then declined to 1,393,215 bbl. in December. Wheeler Ridge, discovered in January, 1923, produced 23,254 bbl., in January, 1924, increased to a high of 33,678 bbl., in September, and declined to 27,430 bbl. in December. 4. Nearly all the production that had been shut-in during 1923 was opened in 1924, except some wells chiefly in Coalinga, Fullerton, and Santa Maria districts. The opening up of this shut-in production, combined with the increased productions from Dominguez and Torrance, were the chief factors that held the rate of decline for the state to a gentle slope.

Jan 7, 1925

By Walter Stephen

MODERN developments in alloy steels have been so rapid and diverse that engineering practice has scarcely had time to re-appraise all items of past experience wherein conclusions became axiomatic under conditions that no longer apply. A case in point is the wet screening of abrasive ores within the fine range still looked upon as belonging exclusively to classifiers. By virtue of the development of stainless steels (18 per cent Cr, 8 per cent Ni), it is no longer true that classifiers are more economical than screens in closed circuit with large-tonnage ball or rod mills at 65 or even 100 mesh, provided a selective overgrind of the higher-gravity constitu-ents of the ore is not desired. Wet screening of ores is a highly corrosive as well as an abrasive opera-tion, because of the inevitably high degree of oxygenation of the water. Screen cloth of ordinary or spring-steel wire almost at once becomes pitted and covered with a film of corrosion products, which causes rust-blinding of fine-mesh screens and offers high frictional impedance to the flow of ore particles. On the other hand, the well-known properties of stainless steel enable it to maintain a bright surface, and so to eliminate blinding either by ore particles or by corrosion products. That a large-tonnage mill grinding hard ore to 65 mesh can be oper-ated economically in closed circuit with screens instead of classifiers has recently been demonstrated at the Copper Cliff concentrator of the International Nickel Co.; in the test to be described, a 6 ½ by 12 ½ -ft. Marcy rod mill ground from 625 to 820 tons. of ore per day to approxi-mately 65 mesh, operating in closed circuit with three 4 by 5-ft. Hum-mer screens, without any classifier.. Stainless-steel cloth gave an indicated life of several months. There was no difficulty with blinding, yet dilution and spray water could be controlled so that screen undersize averaged not less than 40 per cent solids. In contrast, ordinary carbon steel was pitted and blind with rust within 40 hours.

Jan 1, 1938

By Frank C. Green

Drilling for oil and gas in Missouri in 1935 was mostly confined to proven areas, but was marked by the completion of one of the largest oil wells, 53 bbl., and one of the largest gas wells, 2,000,000 cu. ft., drilled in recent years. A new oil pool, discovered in southern Cass County late in 1934, was further developed; a new pool in southern Platte County is possibly indicated by the completion of a single small well, which flowed naturally; and a deeper sand was developed in the Marota gas pool in Jackson County. Completions dropped to a lower level than in any recent year. A total of 73 wells, which included the deepening of 8 old wells, was drilled. In Bates County, there was one gas well with an open flow of 100,000 cu. ft., and one dry hole. Cass County had six oil wells with about 100 bbl. initial production; one gas well with an open flow of 500,000 cu. ft., and three dry holes. In Jackson County there were seven oil wells with 25 bbl. initial production; 24 gas wells with 7,358,968 cu. ft. open flow, and 27 dry holes. Platte County had one oil well, one small gas well and one dry hole. The oil well flowed naturally about 4 or 5 bbl. per day. It is rather difficult to obtain production figures on either oil or gas leases, but in cases where the figures have been given to the writer in confidence, they disclose conditions comparable with many other regions. One oil lease of 32 acres has produced 125,000 bbl. in four years, or nearly 4000 bbl. per acre. Another lease has made 50,000 bbl., or about 3000 bbl. per acre. It is probable that the total daily production at the end of 1935 was close to 200 hill. per day. A gas pool covering less than one square mile has made 110,111,000 cu. ft. in about 18 months. In this period, the open-flow capacity has been reduced from about 10,500,000 cu. ft. per day to about 3,500,000.

Jan 1, 1936

By Frank C. Green

Drilling for oil and gas in Missouri in 1935 was mostly confined to proven areas, but was marked by the completion of one of the largest oil wells, 53 bbl., and one of the largest gas wells, 2,000,000 cu. ft., drilled in recent years. A new oil pool, discovered in southern Cass County late in 1934, was further developed; a new pool in southern Platte County is possibly indicated by the completion of a single small well, which flowed naturally; and a deeper sand was developed in the Marota gas pool in Jackson County. Completions dropped to a lower level than in any recent year. A total of 73 wells, which included the deepening of 8 old wells, was drilled. In Bates County, there was one gas well with an open flow of 100,000 cu. ft., and one dry hole. Cass County had six oil wells with about 100 bbl. initial production; one gas well with an open flow of 500,000 cu. ft., and three dry holes. In Jackson County there were seven oil wells with 25 bbl. initial production; 24 gas wells with 7,358,968 cu. ft. open flow, and 27 dry holes. Platte County had one oil well, one small gas well and one dry hole. The oil well flowed naturally about 4 or 5 bbl. per day. It is rather difficult to obtain production figures on either oil or gas leases, but in cases where the figures have been given to the writer in confidence, they disclose conditions comparable with many other regions. One oil lease of 32 acres has produced 125,000 bbl. in four years, or nearly 4000 bbl. per acre. Another lease has made 50,000 bbl., or about 3000 bbl. per acre. It is probable that the total daily production at the end of 1935 was close to 200 hill. per day. A gas pool covering less than one square mile has made 110,111,000 cu. ft. in about 18 months. In this period, the open-flow capacity has been reduced from about 10,500,000 cu. ft. per day to about 3,500,000.

Jan 1, 1936

By T. S. Taylor

THE development of the linear hot-wire anemometer has been chiefly clue to the efforts of L. V. Kings1 and A. E. Kennelly and H. S. Sanborn.2 The anemometers used by these investigators consisted essentially of a fine heating wire having attached leads for resistance measurements at distances of 10 or more centimeters from each other. In using such an anemometer, the current is measured that is necessary to maintain the resistance of the wire, between the two leads, constant for different air velocities. Thus resistance is always so chosen that the temperature of the heating wire will be sufficiently high to make the observations practically independent of small variations in the temperature of the gas in which the anemometer is placed. The measurement of the resistance of the anemometer wire requires a Kelvin bridge set up, which for commercial work is not altogether desirable. The cooling effect clue to different air velocities depends on the temperature difference between the wire and the gas and the total quantity or mass of gas passing the wire per unit tine. Since the temperature of the wire is maintained constant, the effect observed in the change in the heating currentfor a given change in air velocity is a measure of the difference between the gas flow in the two cases. Such an anemometer, therefore, measures the average gas flow for a length depending on the distance between the two resistance leads. Therefore the instrument in the form used thus far is not very satisfactory for measuring gas velocities in small tubes or in places where the velocity varies rapidly across the line of flow. For the purpose of measuring gas flow through relatively small tubes, where the velocity changes rather rapidly across the tube, the hot-wire anemometer has been modified in the manner shown diagrammatically in Fig. 1. It consists essentially of a platinum heating wire H about 0.007 in. (0.178 mm.) in diameter and ½ to 1 in. (12.7 to 25.4 mm.) long stretched across a suitable framework, say of glass. This wire has

Jan 9, 1919

By H. W. Kerr, B. Soutiere

THE possibility of using unidirectionally solidified eutectic alloys as high-strength composite materials has been investigated by several workers. Unidirectionally solidified lamellar and fibrous eutectics have been shown to have good short-time structural stability at temperatures close to the eutectic melting temperature.'-4 Several investigations of both short-time high temperature tensile properties and creep properties of eutectic alloys have been carried out,3-" with promising results. Little work has been reported, however, on the thermal stability of eutectic alloys which have been unidirectionally solidified and subsequently deformed in compression. Since processes such as rolling and grinding introduce compressive stresses, and since the properties depend on the spacing and perfection of the composite structure10,11 this aspect is of definite importance if unidirectionally solidified eutectic alloys are to be considered for commercial use. A Cd-Zn alloy made from 99.999 pct starting materials was cast into a graphite boat and zone levelled12 to obtain a completely lamellar structure at one end of the bar. Sections from this region of the bar were removed, recast into 6.5 mm I.D. Pyrex tubing, and solidified unidirectionally upwards at a rate of 2.8 cm per hr. Specimens were cut from the solidified rods, heated in air at 200°C (0.88 of the eutectic melting temperature) for various lengths of time, and examined metal-lographically. Compression specimens were also cut from the solidified rod carefully machined to a length of & in., and deformed with the compressive axis parallel to the original growth axis to produce a total longitudinal strain of 12 pct. Some of these specimens were examined metallographically; others were heated in air at 200°C for various lengths of time and then examined. Metallographic examination of the deformed specimens showed the two types of deformation previously described; slip lines13 (smoothly bent lamellae) and kinks13,14 (sharply bent lamellae). Very close to the specimen ends there were a large number of deformation bands, but at a distance of about -re- in. the deformation was very localized, as shown in Fig. 1.

Jan 1, 1970

By F. J. Tuck

THE Hayden mill of the Ray Mines Division, Kennecott Copper Corporation, is now equipped with two 9 by 12-ft. rod mills having a daily capacity of 6000 tons of coarse-crushing plant product from the mine. These two mills crush a ¾ -in. product to approximately 19 per cent on 14 mesh, with only one pass through the mills. Each rod mill has taken the place of four sets of 42-in. Garfield rolls with their attendant screens, and is making a product for the fine-grinding department comparable to that formerly made by rolls in closed circuit with screens. The rod mills are lined with wave-type liners of white iron, varying in thickness from 2 to 3 in. The shell and end liners last approximately 600 to 700 days. Manganese-steel lifter bars, 3 5/8 in. thick, are used, spaced about 11 in. apart, and they give a life of 350 to 450 days. Fig. 1 shows the general design and thickness of the wave-type liners and lifter bars; 1 ½ -in. liner bolts are used to fasten the lifter bars to the shell. The shell liners are held in place by the tapered lifter bars. A 3/4-in. wood backing is used between the shell and the liners. The rod-mill scoop has removable manganese-steel lips, which last 250 to 300 days. The scoop proper has shown some wear in spots, and these spots have been protected by rubber bolted over them. Water and milk of lime are added to the elevator feeding the mill, but not enough water to cause a pounding of the rods against the shell. Roughly, the water added amounts to 25 to 33 per cent of the ore. Additional water is added to the mill discharge to facilitate distribution to the classifier bowls in the fine-grinding department. Rods are charged to the mill once every four days, the mill being down about 20 min. for this purpose. Other delays are negligible, and usually are due to a loose liner bolt or possibly power trouble. However, these occasions are extremely rare. In charging the mill, a crane is used

Jan 1, 1938

By E. L. Estabrook

Oil companies operating in foreign countries have made increased use during 1930 of cooperative agreements in prospecting unproven territory and in developing proven territory. A considerable proportion of the existing foreign fields are held under single ownership and have been developed as units. The operating companies seek to maintain this condition by acquiring land in large blocks or by merging smaller concessions under unit operating agreements. Your committee has secured a number of reports on foreign non-competitive operations and a valuable formal paper which deals with the Golden Lane of Mexico.l 0. B. Knight has drawn some valuable comparisons concerning costs of development and ultimate production between a certain competitive area and another noncompetitive area along that strip of rich producing territory. After discussing details of production, numbers of wells and cost of drilling and production, he concludes that the 93,700,000 bbl. of competitive oil will have cost $0.193 per barrel as compared to 85,700,000 bbl. of noncompetitive oil at $0.059 per barrel. The saving of $0.134 per barrel amounts in round figures to $11,500,000, which is 21/2 times the total cost of developing the non-competitive block. The cost for drilling and development of the two areas of 3550 acres which Mr. Knight compares was $18,150,000 under competitive and $4,760,000 under noncompetitive conditions. The estimated ultimate production of the competitive 3550 acres is expected to reach 93,700,000 bbl., or 8,000,000 bbl. above the noncompetitive block. Under ordinary production methods it is to be expected that a noncompetitive area will yield less oil per unit area than will a similar competitive area, because of closer spacing and more rapid extraction in the latter case. The advantage of noncompetitive conditions, in this regard, is that the undivided ownership makes it possible to apply repressuring as a production method fairly early in the life of the field and thus, in the end, to vastly increase the yield. In the particular region described by Mr. Knight, repressuring is not thought to be a factor of

Jan 1, 1931

By M. Albertson

AT Cobalt, Ontario, Canada, a lake was drained to facilitate mining, by the Mining Corpn. of Canada, during the spring and early summer of 1915. Previous to pumping out the water, great quantities of sands and slimes from concentrating plants had been discharged into the lake and during and after the lake's drainage, its basin' Was a receptacle for tailing products. As the writer was at work along the shore line as the lake was being drained, he had a good opportunity to observe the changes that took place as the water was withdrawn. Some adjustments between the incoming sands and the mud in the lake had taken place before pumping was commenced. One of the most interesting results was the appearance of a small dome in a path the writer traversed twice a day for several months; he remembers distinctly the difficulty of crossing this. Cobalt Lake owed its existence to the gouging out of a rock basin by glaciation. The long axis of the basin closely follows the strike of a thrust fault of about 500 ft. (160 in.) vertical displacement. The lake was originally shaped somewhat as shown. The length was about 3000 ft. (914.4 in.), the width at the lower lobe was about. 1000 ft., and the, width at the narrows probably. 400 to 500 ft. The original depth of water varied from 20, to 30 ft. (6.1 to 9.1 m.), near where the island later was formed, to 60 to 70 ft. (23.6 to 27.6 m.) in the widest part of the lower lobe. At the narrows, the depth was 30 to 40 ft.. Above the bed rock was sand, with boulders near the bottom, and mud. During the building of the railroad in 1903, considerable filling was done along the right of way. With the commencement of mining operations, about 1905, waste rock and mill tailings were dumped into the lake. One of the mining companies operated a hydraulic giant to remove the glacial debris from several hundred acres of rock surface; much of the sand and clay from this operation was deposited in the. lake. About

Jan 2, 1921