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Rep. William S. Hill (R.- Colo.) will preside over a Congressional hearing investigating the problems of the mining industry to be conducted in Phoenix, Ariz., late in April. Rep. Hill has expressed the desire to hear from the industry itself all possible testimony on the needs of domestic mining and how Congress can help. Rep. John J. Rhodes of Arizona is also expected to attend the hearing. Two new features are incorporated into an SO2 process for treatment of low grade manganese ores disclosed by Chemical Construction Corp. The new approach includes a high temperature autoclaving step and a sintering operation. Data was given for work performed on Cuyuna Range ores.

Jan 4, 1953

By Arthur F. L. Bell

Discussion of the paper of ARTHUR F. L. BELL, presented at the San Francisco meeting, September, 1915, and printed in Bulletin No. 105, September, 1915, pp. 1769 to 1799. WILLIAM A. WILLIAMS, San Francisco, Cal.-Is the Union Avila plant run as a topping plant or as a dehydrating plant? A. F. L. BELL, San Francisco, Cal.-Both. It takes off an average of 20 per cent. water besides topping the oil. Part of the crude oil is run through an electrical separator before running to the topping plant, but the entire crude averages about 20 per cent. when it enters the topping plant. DAVID T. DAY, Washington, D. C.-I suppose most of the work contemplated in these large topping plants is simply to deal with topping the oils with only a small percentage of water in them. A. F. L. BELL.-Not more than 2 per cent. of water can be handled in ordinary stills without causing trouble. At our Gavotte refinery, where the oil runs from 15 to 30 per cent. water, we carry 20 lb., pressure oil our stills to hold the framing down, we can do that with small stills, with large one's it would not be safe; but with a retort, the quantity of water contained in the oil does not affect its working. It simply means additional fuel to evaporate the water.

Jan 12, 1915

By James Terry Duce

The symposium on production for the year 1940 contains few papers on the foreign situation. It is probable that the foreign part of next year's symposium will be even shorter. This is due to rigid censorship in various countries, as the question of the volume of petroleum supplies has become one of great strategic importance. This is even more true than in the last war, owing to greater mechanization of armies. 'It has always been the policy of officers in charge of the symposium to refrain from publishing information that might possibly injure national or private interests. At the close of the war we hope again to publish full and accurate records of production abroad. Excerpts from Circular to Authors In order to facilitate interpretation of the data in this chapter, we print the following excerpts from the Circular to Authors. The field is the unit in this tabulation. In cases of fields extending across State boundaries, such as Rodessa, it is suggested that each State author treat the section of the field in his State as a unit, and by a footnote indicate that the field extends into an adjacent State. Each space in Table I may represent one of four possibilities; either it is not applicable to the particular field, or the proper entry is not determinable, or the proper entry may be determinable but is not determinable from data available to the author, or the proper entry is determinable. When spaces are not applicable, leave blank; in spaces where the proper entries are determinable but not de-terminable frod data available to the author, please inserty; in spaces where the proper entries are determinable by the author, make such entries. y implies a hope that in some future year a definite figure will be available. The entry of a zero is a positive declaration, and an important declaration where it is in order. Inability to determine precisely the correct entry for a particular space should not lead the author to insert merely y. Contributions of great value may be made by the author in many cases where entries are not subject to precise determination. In sucli cases the author should use his good judgment and make the best entry possible under the circumstances. For many spaces the correct entries represent the opinion of the author (for example, "Area Proved') and in such cases the entry need not be hedged to such extent as when the quantities are definite yet can be ascertained only approximately by the author. In cases under definite headings but where figures are only approximate, the author may use x. It is thought that the nearest whole numbers are sufficiently accurate for our purposes except as to percentage of sulphur in oil. If an author desires to report any other figures to tenths, he may do so. The quantity of gas produced should include, where possible, gas sold or otherwise marketed, and gas blown into the air, burned as flares or otherwise wasted. Segregation of these figures would be interesting if the authors can make such segregation. In any event, the figures should represent as nearly as possible the total quantity of gas removed from the reservoir. Under the columns on "Depth," the average depth to the top of the productive zones and to the bottom of the productive wells, when

Jan 1, 1941

By J. F. Bryson

Instantaneous outbursts of coal in underground workings have occurred frequently in various coal fields in Nova Scotia; British Columbia; Canada; South Staffordshire, England; and the states of Washington, Virginia, West Virginia and eastern Kentucky in the United States. Such outbursts in eastern Kentucky have been called "mountain bumps " because they are more likely to occur under mountain cover than elsewhere, but recently they have become generally known as "coal bumps." The eastern Kentucky coal field has been troubled by these outbursts since 1923. Many men have been injured and killed, and the morale of the workmen in the vicinity of such outbursts has been affected to such an extent that mine production has suffered for a considerable period following each outburst. Such phenonlenal occurrence in any coal field naturally has led to discussion as to the cause and means of prevention. In the eastern Kentucky field, local mine officials, workmen, mining engineers, and many others have offered many ideas as to the cause and many methods of prevention have been suggested, and tried without success. Some of the plans were either practically or economically unsound and in general impossible to follow. To enumerate all the suggestions would require a large volume. One cause mentioned was that they might be due to gas under high pressure, as in Lower Silesian mines, and the remedy reeommcnded was to drain the gas by drilling holes into a suspected area. A hole 30 ft. long was drilled into a 60-ft. pillar to allow the gas to drain off, hut the pillar bumped the next day. Realizing the importance of obtaining the best information available on coal bumps, the writer, with the permission of the Harlan County Coal Operators' Assoeiation, invited Mr. George S. Rire, Chief Mining Engineer of the U.S. Bureau of Mines, who had investigated bumps in several countries, to conduct an investigation of coal bumps in this field. Mr. Rice, by permission of the Director of the G.S. Bureau of Mines, accepted the invitation, and it was the writer's privilege, in company with

Jan 1, 1936

By J. F. Bryson

Instantaneous outbursts of coal in underground workings have occurred frequently in various coal fields in Nova Scotia; British Columbia; Canada; South Staffordshire, England; and the states of Washington, Virginia, West Virginia and eastern Kentucky in the United States. Such outbursts in eastern Kentucky have been called "mountain bumps " because they are more likely to occur under mountain cover than elsewhere, but recently they have become generally known as "coal bumps." The eastern Kentucky coal field has been troubled by these outbursts since 1923. Many men have been injured and killed, and the morale of the workmen in the vicinity of such outbursts has been affected to such an extent that mine production has suffered for a considerable period following each outburst. Such phenonlenal occurrence in any coal field naturally has led to discussion as to the cause and means of prevention. In the eastern Kentucky field, local mine officials, workmen, mining engineers, and many others have offered many ideas as to the cause and many methods of prevention have been suggested, and tried without success. Some of the plans were either practically or economically unsound and in general impossible to follow. To enumerate all the suggestions would require a large volume. One cause mentioned was that they might be due to gas under high pressure, as in Lower Silesian mines, and the remedy reeommcnded was to drain the gas by drilling holes into a suspected area. A hole 30 ft. long was drilled into a 60-ft. pillar to allow the gas to drain off, hut the pillar bumped the next day. Realizing the importance of obtaining the best information available on coal bumps, the writer, with the permission of the Harlan County Coal Operators' Assoeiation, invited Mr. George S. Rire, Chief Mining Engineer of the U.S. Bureau of Mines, who had investigated bumps in several countries, to conduct an investigation of coal bumps in this field. Mr. Rice, by permission of the Director of the G.S. Bureau of Mines, accepted the invitation, and it was the writer's privilege, in company with

Jan 1, 1936

By Roger Holmberg, Kenneth Mäki

This paper describe; open pit studies where blasting damage introduced in the remaining rock has been investigated. Results from two open pit mines are described and discussed. Parallel performed laboratory experiments, where simulated blasting damage has been introduced into samples before shear strength testing took place, are also reviewed. These studies are tied together in order to throw some light upon how the blasting damage influences the slope stability. A mathematical model is also described which will make it possible to optimize the blast design for a specified damage zone in the rock mass.

Jan 1, 1983

By H. S. Kalish, F. J. Dunkerley

Introduction and Previous Work THE determination of the low temperature tensile properties of tin and tin-lead alloys was initiated as part of an extensive research program on the phasial equilibria of tin binary systems below 13.2°C and the property changes associated therewith. A survey of the literature revealed that, although some room temperature tensile data were available for tin and a few tin-lead alloys, there existed no survey report of the low tcmPerature tensile properties of these alloys. Accordingly, the tensile data for tin and a series of pure tin alloys containing from 0.01 to 50 pet lead were measured at eleven temperatures horn — 196 to +20°C and are presented here in survey form. In addition to the importance of these tensile data as a preliminary to certain fundamental research, this information promises also to be of commercial importance because of the extensive use now being made of tin-lead solders in refrigeration and gas liquefaction equipment. Occasional failures of the solders in low temperature service have been attributed by some metallurgists to low temperature embrittlement, while others hold that failure results from the transformation of the tin-rich phase of the solder from the solid white (beta) to the powdered gray (alpha) form. From the data previously available in the literature, neither of these explanations can be completely corroborated. cohen and van Lieshout have estab-lished the beta to alpha tin transformation at 13,2°C and have shown that strain accelerates the transformation. Further, they showed that although I pct lead retarded the transformation, it was not eliminated. It will be pertinent, then, to note whether the beta to alpha transformation of the tin.rich phase will occur in a short-time tensile 'test. polanyi and schmid2 studied the tensile properties of tin single crystals at — 185°~ and report that tin is britlle at this tem-perature. In 1946, Kostenets3 reported that pure tin was brittle at —Ig6 and — 253°~, while lead remained ductile at both these temperatures. He also studied the tensile properties of tin-lead alloys containing from 10 to 75 pet lead at —253, —196 and + I~OC. The ultimate tensile strength increased more than two times in going from room temperature to — I96°C and about three times that value on further cooling to — 253 C- All the alloys were brittle at — 196'C except those containing more than 75 pct lead. Even at — 253'C, the 75 pct lead alloy retained 36 pet elongation in a 30 mm-ga. length. Creep is also an important phenomenon

Jan 1, 1949

The following is an incomplete list of members and guests who called at Institute headquarters during the period Apr. 10, 1919, to May 10, 1919. Arthur K. Adams, Spencer, Mass. Ensign Floyd D. James, U. S. S. Fulton. W. T. Bates, New York City, N. Y. J. Harry Johns, Thorsden, Woking, A. D. Brokaw, Washington, D. C. England. E. H. Clausen, San Francisco, Calif. W. F. Jones, Rock Springs, Wyo. W. M. Corse, Mansfield, Ohio. E. L. Lasier, Washington, D. C. E. O. Daue, Philadelphia, Pa. John M. Lovejoy, New Rochelle, N. Y. G. D. Dub, Washington,, D. C. 2d Lieut. James F. Magee, Lancaster, S. B. Eaton, Dover, N. J. Pa., Sherman Eaton, Smethport, N. C. Ernest Marquardt, Casper, Wyo. J. A. Endweiss, La Jolla, Calif. Geo. B. Marshall, Abangarez, Costa Edgar W. Engle, North Chicago, Ill. Rica. 2d Lieut. Maxwell E. Erdofy, New York Benj. L. Miller, So. Bethlehem, Pa. City, N. Y. Major Desaix B. Myers, Camp Mills. Chas. A. Fellencer, Allentown, Pa. Edmund Newton, New York City, N. Y. Arthur Feust, Joplin, Mo. Seely B. Patterson, Jr., Allentown, Pa. Ensign Harold P. Ford, U. S. S. Radnor. Wm. R. Pearson, New York City, N. Y. A. D. R. Galloway, Accra, West Africa. Harold C. Price, Langeloth, Pa. R. C. Gosrow, Milwaukee, Wis. T. C. Roberts, East. Orange, N. J. C. A. Grabill, El Paso, Tex. P. H. Royster, Washington, D. C. Hobart A. Hanks, San Francisco, Calif. W. H. Staver, New York City, N. Y. John L. Henning, Lake Charles, La. N. L. Wimmler, Bangkok, Siam. 1st Lieut. J. Parke Hook, Philadelphia, Capt. Jay P. Wood, New York City, Pa. N. Y. An item in the May Bulletin made it appear that Frank W. DeWolf had just become connected with the State Geological Survey of Illinois. This was one of the inadvertences of war. Mr. De Wolf has been Director, or Chief, of the State Geological Survey for approximately ten years. Through the courtesy of the Governor of Illinois, lie was loaned to the Bureau of Mines for about seven months, after which period he resumed his former position.

Jan 6, 1919

Discussion of the paper of Earl S. Bardwell, presented at the Butte meeting, August, 1913, and printed in Bulletin No. 79, July, 1913, pp. .1429 to 1441. H. O. HOFMAN, Boston, Mass. (communication to the Secretary*) :-It is pleasing to the originators of the planimetric determination of oxygen in refined copper to see that the method has been taken up by a large smelting plant to be used in every-day work after it has been simplified to suit the new conditions. Several years ago Huntington and Desch 1 had improved our mode of working. They projected the developed negative on to a screen, traced the outlines of the picture with a pencil, drew a border, and measured one constituent with. the planimeter. In order to give the work greater precision, they divided the area into squares of 1 cm. side, shaded the

Jan 11, 1913

By M. Tanaka, S. Kita, Y. Jinnouchi, Y. Sawada

This paper generalizes the results of the recent theoretical and experimental investigations on the air-pulsated jigs in Japan. The pulsating mechanism is analyzed as a special vibratory system, and the jigging mechanism as a mass system subjected to the law of hindered settling. The results of investigations on the following items are reviewed: dynamics of the pulsating mechanism; pulsation in a practical TACUB jig development of a new type of air valve; uniform pulsation in a large Baum jig; motion and mobility of bed particles; separating speed in hindered conditions; and standard deviation in practical jigs.

Jan 1, 1985

By A. U. Seybolt

A. U. Seybolt (General Electric Research Laboratory)— As pointed out in an earlier paper,41 it appears to be very difficult to nucleate Si3N4 in Si-Fe of silicon content up to around 5 pet. Therefore, one observes, as did Pearce, that equilibrations with nitrogen gas yield only nitrogen in solid solution at temperatures above about 700°C, or, as Pearce found, 770°C. Evidently, the free energy of formation of Si3N4 only becomes high enough at -770°C to overcome the reluctance of Si3N4 to nucleate. However, as mentioned in Ref. 41, if some Si3N4 is first formed by a mixture of ammonia and hydrogen, one can then replace this gas mixture by nitrogen gas, and either increase or decrease the amount of Si3N4 present at any temperature by suitable adjustment of nitrogen pressure: that is, to equilibrate with Si3N4. In the equilibration experiments cited in Ref. 41, equilibrium was approached from both sides, and it was found that samples up to 944oC, at least, were in equilibrium with Si3N4. Higher temperatures were not employed, as this would have necessitated a redesign of the apparatus for using nitrogen pressures in excess of 1 atm. To summarize, the results of Pearce's experiments and those of Ref. 41 cannot be directly compared because two quite different equilibria were studied. Therefore, the statement by Pearce on p. 1398 indicating apparent error in Ref. 41 is unjustified. M. L. Pearce (author's reply)— There was limited evidence obtained in the current investigation which would indicate that excessive "supercooling" did not occur. A small piece of the same resulting from heat treatment No. 5 in Table III was subsequently held at 800°C for 16 hr in 95 pet N-5 pet H. Isotope-

Jan 1, 1964

By R. H. King

This paper describes the results of an underground coal mine trial installation of a shielded trailing cable. The cable was a three conductor, round, type SHC-GC and was installed on a shuttle car in a conventional room-and-pillar mining section. The purpose of the study was to evaluate proposed legislation that would require shielding on low-voltage trailing cables. Such legislation would require machine modifications to cable reels, packing glands, and couplers; increase cable splicing complexity; and necessitate additional splicing materials and training. Furthermore, fault location might be more difficult. Even though shielding will cause some problems for the mine operator, it can reduce electrical shock hazard to mine workers. This paper presents information that mine operators can use to solve most of the problems encountered if they are required to install shielded cables. The in-mine evaluation was funded by the US Bureau of Mines; however, the views and conclusions in this paper are those of the author and should not be interpreted as necessarily representing official policies of the US government.

Jan 1, 1982

By Basil B. Zavoico

The symposium on production for the year 1942 contains no papers on the foreign situation except those on Argentina and Mexico. It has always been the policy of officers in charge of the symposium to refrain from publishing information that might possibly injure national or private interests. At the close of the war we hope again to publish full and accurate records of production abroad. Excerpts From Circular to Authors In order to facilitate interpretation of the data in this chapter, we print the following excerpts from the Circular to Authors. The field is the unit in this tabulation. In cases of fields extending across State boundaries, such as Rodessa, it is suggested that each State author treat the section of the field in his State as a unit, and by a footnote indicate that the field extends into an adjacent State. Each space in Table I may represent one of four possibilities; either it is not applicable to the particular field, or the proper entry is not determinable, or the proper entry may be determinable but is not determinable from data available to the author, or the proper entry is determinable. When spaces are not applicable, leave blank; in spaces where the proper entries are determinable but not determinable from data available to the author, please insert y; in spaces where the proper entries are determinable by the author, make such entries. y implies a Rope that in some future year a definite figure will be available. The entry of a zero is a positive declaration, and it is an important declaration where it is in order. Inability to determine precisely the correct entry for a particular space should not lead the author to insert merely y. Contributions of great value may be made by the author in many cases where entries are not subject to precise determination. In such cases the author should use his good judgment and make the best entry possible under the circumstances. For many spaces the correct entries represent the opinion of the author (for example, "Area Proved") and in such cases the entry need not be hedged to such extent as when the quantities are definite yet can be ascertained only approximately by the author. In cases under definite headings but where figures are only approximate, the author may use x. It is thought that the nearest whole numbers are sufficiently accurate for our purposes except as to percentage of sulphur in oil. If an author desires to report any other figures to tenths, he may do so. The quantity of gas produced should include, where possible, gas sold or otherwise marketed, and gas blown into the air, burned as flares or otherwise wasted. Segregation of these figures would be interesting if the authors can make such segregation. In any event, the figures should represent as nearly as possible the total quantity of gas removed from the reservoir. Under the columns on "Depth," the average depth to the top of the productive zones and to the bottom of the productive wells, when subtracted, should give the approximate thickness of the productive zone. For fields where this is not true because of unusually high dip or for some other reasons, it is suggested that the authors indicate in their text the approximate average thickness of the productive zone.

Jan 1, 1943

By James Terry Duce

The symposium on production for the year 1940 contains few papers on the foreign situation. It is probable that the foreign part of next year's symposium will be even shorter. This is due to rigid censorship in various countries, as the question of the volume of petroleum supplies has become one of great strategic importance. This is even more true than in the last war, owing to greater mechanization of armies. 'It has always been the policy of officers in charge of the symposium to refrain from publishing information that might possibly injure national or private interests. At the close of the war we hope again to publish full and accurate records of production abroad. Excerpts from Circular to Authors In order to facilitate interpretation of the data in this chapter, we print the following excerpts from the Circular to Authors. The field is the unit in this tabulation. In cases of fields extending across State boundaries, such as Rodessa, it is suggested that each State author treat the section of the field in his State as a unit, and by a footnote indicate that the field extends into an adjacent State. Each space in Table I may represent one of four possibilities; either it is not applicable to the particular field, or the proper entry is not determinable, or the proper entry may be determinable but is not determinable from data available to the author, or the proper entry is determinable. When spaces are not applicable, leave blank; in spaces where the proper entries are determinable but not de-terminable frod data available to the author, please inserty; in spaces where the proper entries are determinable by the author, make such entries. y implies a hope that in some future year a definite figure will be available. The entry of a zero is a positive declaration, and an important declaration where it is in order. Inability to determine precisely the correct entry for a particular space should not lead the author to insert merely y. Contributions of great value may be made by the author in many cases where entries are not subject to precise determination. In sucli cases the author should use his good judgment and make the best entry possible under the circumstances. For many spaces the correct entries represent the opinion of the author (for example, "Area Proved') and in such cases the entry need not be hedged to such extent as when the quantities are definite yet can be ascertained only approximately by the author. In cases under definite headings but where figures are only approximate, the author may use x. It is thought that the nearest whole numbers are sufficiently accurate for our purposes except as to percentage of sulphur in oil. If an author desires to report any other figures to tenths, he may do so. The quantity of gas produced should include, where possible, gas sold or otherwise marketed, and gas blown into the air, burned as flares or otherwise wasted. Segregation of these figures would be interesting if the authors can make such segregation. In any event, the figures should represent as nearly as possible the total quantity of gas removed from the reservoir. Under the columns on "Depth," the average depth to the top of the productive zones and to the bottom of the productive wells, when

Jan 1, 1941

By M. R. Daly

In a recent paper on Geologic Structure in the Cushing Oil and Gas Field, Oklahoma,l Carl H. Beal has pointed out some interesting peculiarities in the distribution of the hydrocarbons and the disposition of the "planes of separation" between the oil and the water (water surfaces). Mr. Beal's principal statements on this matter may be, summarized as follows: I. In every important dome in the Cushing field, which has not been complicated by folding along its sides, the oil area in each of the three oil and gas sands studied (Layton, Wheeler and Bartlesville) apparently extends farther down on the long axis of the dome than it does on the steeper sides. The result is that water is encountered at a lesser depth below datum plane (sea level) on the steep sides of the dome than along the ends where the beds are more gently tilted. II. In the Layton and Wheeler sands (to which the detailed study of water surfaces has been almost entirely confined), the water surface is not level, but dips at a gentle angle (maximum dip 100 ft. to the mile) away from the center of the structure. This inclination existed prior to development, and it has been rendered greater by the rapid extraction of oil and gas. To these statements, the following observations are added: The dominant structural feature in the Cushing field is a broad north and south anticlinal fold, along whose axis the domes are distributed (Fig. 1, p. 897), and the more important oil areas in each sand lie on the west side of the field. In many cases, gas has been forced to the east side of the structure, sometimes as far as the water line. From the distribution of the oil and gas bodies, Mr. Beal concludes that the hydrocarbons in this region probably migrated from the west or the northwest. It seems as if these different features would be susceptible of some

Jan 1, 1918

By Hu Weibei

This paper describes the development and implementation of the control system in the flotation plants of China. The control system can be categorized as: Control in the crushing circuits: Automatic control of the flow rate of the crusher. Control in the grinding circuits: Control of the feed rate of the grinding mill and circulating load. PSM-200, an indigenous particle size monitor, and gamma-ray density gauges are utilized. Control in the flotation circuits: pH control, flotation reagent dosage estimation and control, pulp level control, aeration control, etc. Complete grinding-flotation circuits control is based on minicomputer operations. Some typical control systems which have been applied in copper flotation plants are summarized and specific problems discussed.

Jan 1, 1984

By G. B. Misra

While investigating on the aerodynamic resistance of airways supported with peripheral timber sets, at regular intervals, the following theoretical equations were developed by the author to estimate the resistance coefficient of such airways: [ ] for S < 1, where f is Darcy-Weisbach resistance coefficient of the airway, C is modified drag coefficient of the supporting member, D is equivalent diameter of the bare airway, 8 is ratio of the approach velocity over the sets to the average velocity of the bare airway, A is cross-sectional area of the bare airway, a is projected frontal area of the sets, A., is cross-sectional area of the air stream at the vena contracta inside the set, S is spacing of the sets, f, is resistance coefficient of the bare airway, l is length of aerodynamic influence of sets, p is perimeter of the bare airway, p, is setted portion of the perimeter of the bare airway, pe is unsetted portion of the perimeter of the bare airway, and P shielding factor. The equations were verified experimentally in a model rectangular airway supported with one- (bars), three-, and four-piece sets of square-section timber of three different sizes and were found to hold true. The work has been further extended to one-, three-, and four-piece sets of round timber of 2.6, 3.2, and 3.8 cm diam with the same experimental set up. Tests have been carried out for spacings of 25, 50, 75, 100, 150, and 200 cm over a regime of flow defined by the Reynolds number (with respect to the equivalent diameter of the bare duct) ranging from about 1.5 X 106 to 5 X 106 using the same experimental techniques. The values of f are calculated in the manner indicated in [Ref. 1]. Unlike with square-section timber, the resistance coefficient f of the airway setted with round timber shows a distinct variation with the Reynolds number of flow. This conforms to observations made by Sales and Hinsley.2 In order to have a comparable value of f for all types of sets with all sizes of timber, it was necessary to select the value of f at a fixed Reynolds number of flow. Since f is chiefly a function of the drag coefficient of the sets, the appropriate Reynolds number RE is that with respect to the diameter of timber in the set. Considering the diameters of timber used and the regime of flow over which measurements were made, f was chosen at a value of RE = 20,000 in all cases. The f vs. S curves are maximal in nature and in conformity with theory, the f vs. 1/S curves are straight lines up to a value of S = 1 beyond which they show a distinct flexure. The observed values of 1, the length of aerodynamic influence of sets, agree with the relation 1 = 42 e, developed for square-section timber sets, thus suggesting that the shape of timber has little influence on the length of aerodynamic influence. The value of the modified drag coefficient CD for round timber was calculated in the same way as for square timber in Ref. 1, taking the contraction factor Z = 1.5 for round-edged constrictions. CD has an average value of 0.96 with a standard deviation of 6.08% as compared to the free stream drag coefficient of 1.2 at RE = 20,000 for long cylindrical obstructions The shielding factor [ ] is plotted against S/1 in [Fig. 1]. The curves are more or less independent of the size of timber, but are different for the different types of sets, possibly due to their different degree of symmetry. Values of f calculated by the author&apos;s [Eqs. 1 and 2], using experimental values of CD&apos; and [ ] and taking I = 42 e, are plotted in [Fig. 2] against experimentally measured values of f for different types of sets with different sizes of round timber. The values agree closely with a standard deviation of only 5%, thus establishing the veracity of the theoretical equations developed by the author for round timber as well. A comparison was made between the Xenofontowa4 equations (the only other reasonable relations available for the estimation of the resistance coefficient of supported airways) and the author&apos;s [Eqs. 1 and 2] by comparing in [Fig. 3] the values of the resistance coefficient f computed by the Xenofontowa relations with those experimentally measured by the author. In order to make

Jan 1, 1975

By J. W. Harshbarger, E. L. Montgomery

The region of metallic ore deposits in northern Chile, southern Peru, western Bolivia, and northwestern Argentina occurs in arid zones at altitudes as high as 6 km (19,700 ft). Because surface water supplies are meager, new mines require unexploited sources of water. Prolific ground water aquifers occur in salar basins in this region of the Andean Highlands. Exploration water wells have been constructed and aquifer characteristics have been tested in eight salar basins. Results indicate ground water quality is good. Aquifer transmissivity and storage computed from results of pumping tests indicate maximum capacities of more than 170 L/sec (2700 gpm) for individual production water wells. Results of investigations conducted by the authors demonstrate that ground water reservoirs in the Andean Highlands comprise a source of large quantities of water for the mineral industry.

Jan 1, 1986

FOR this Famous Mining Enterprise issue MINING ENGINEERING selected the company that started the zinc in dustry in the United States. The New Jersey Zinc Co. has been a supplier of zinc products to the nation&apos;s industries for more than 104 years. Its Horse Head trade mark is famous throughout the world.

Jan 12, 1953

By Carl J. Christensen

This paper presents the development of diamond coring of the Weber sand section in the Rangely Field, Colorado. The description and operation of the diamond-coring equipment is included as well as the economics and results obtained by its use. Diamond coring is compared with the other methods used for drilling the Weber sand. Two types of diamond coring are discussed. The first and the one used most extensively is the regular 6 ?x 3¾-in. diamond bit and bottom hole 50-ft barrel. The second type, which has also been used successfully by Stanolind, consists of a 4 13/16 x 2 11/32-in. cutting bit and reverse circulation coring equipment. The first type will be referred to as regular or conventional diamond coring while the latter type will be referred to as reverse circulation diamond coring. Introduction Diamond coring has been used for many years in mines, quarries, surface coring at dam sites, laboratory work, and so on, but, until recently, had never been used very extensively in coring oil sands and other oil-bearing strata. It was demonstrated early in its development that hard forma-tions could be cut rapidly and that core recoveries far exceeded those obtained with conventional hard rock bits and quite often 100 pet recovery was obtained. However, the poorly constructed diamond-coring equipment and resulting high costs of early diamond coring slowed down its progress. Early in the development Of the Rangely Weber field, Rio Blanco County, Colorado, the Rangely Engineering Committee selected key wells that were to core the Weber section in its entirety. These cores were to be analyzed and various sections tested to gather sufficient information so that accurate reservoir studies could be made. The number of wells selected were kept at a minimum inasmuch as the productive Weber section, which is found at an approximate depth of 6000 ft, is thick, being as much as 600 to 700 ft on top of the structure. The Weber section is also comparatively hard to drill. For instance, one well took 60 days to core 490 ft of Weber sand with conventional coring equipment. It was noticed, however, that Core Labora-verse diamond plug cutter could quickly cut a plug from. one of these hard cores. This fact led to the serious consideration of diamond coring the Weber sand. The first diamond coring at Randy was performed by Stanolind in August 1946 andl although we experienced some difficulties, the results definitely indicated that diamond coring would be successful at Rangely for .coring the Weber sand. As more wells were cored and the equipment improved somewhat, diamond coring became less expensive than drilling the Weber sand with the conventional rock bit. In less than one Year diamond coring has definitely Proved its usefulness in oil-field drilling operations in the Rocky Mountain area where formations quite often drill very hard. The practice of spot coring in hard oil-bearing formations with conventional coring equipment is giving way diaimond coring of the entire sections, thus givng an operator the complete picture.

Jan 1, 1948