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By M. C. Van Camp, J. D. Miller

Preliminary results are reported regarding the design and development of a pilot scale air sparged hydrocyclone for cleaning fine coal 590 pm (- 28 mesh) containing 24% ash and 1.6% sulfur. The principle of separation is the flotation of hydrophobic coal particles in the centnjugal field generated by the fluid flow in the air sparged hydrocyclone as discussed in another publication. This 152-mm (6-in.) hydrocyclone has a nominal capacity of 0.9 t/h (1 tph) and experimental results suggest that separations vastly superior to a water-only cyclone are possible. In addition the separation efficiency is as good, if not better, than that achieved with conventional flotation cells. For example, typical results indicate that 75% clean coal can be recovered at 15% ash leaving a tailing product of almost 50% ash. These experimental results coupled with the high capacity of the air sparged hydrocyclone (imagine a retention time for flotation of only two seconds compared to two minutes for conventional flotation) may represent a significant breakthrough, not only in coal preparation technology, but in the flotation of fine particles in general.

Jan 1, 1983

By Walter Miller

During no similar period in the development of petroleum refining technology has so much progress been made in methods and equipment for the economical utilization of heat. Drastically severe commercial and economical conditions controlling the refining industry during 1927 gave a great impetus to improved efficiency and more economical operation in all departments. I think it is fair to say, however, that more progress has been made in the department of heat utilization than in other branches. I use the word utilization advisedly in the dual sense of better primary generation and application of heat and of saving by recovery methods. It was because of this trend that the subject, "Economical Application of Heat," was made the keynote of the refinery engineering sessions just completed. No new, outstanding elemental discoveries can be claimed for the year along this line. Some of the progress made has been in the development of better furnaces and distilling equipment embodying the more modern principles of boiler practice in obtaining complete combustion of the fuel, low excess air requirements and high transfer rates through the heating surface. Transfer rates of 3000 to 6000 B. t. u. per sq. ft. per hr. were considered good some time ago in the older type of equipment. Today a transfer rate of 25,000 to 35,000 B. t. u. is an actual accomplishment in commercial installations and engineers are talking of the feasibility of 50,000, 75,000, even 100,000 R. t. u. per sq. ft. per hr. Contributing most to bringing this about have been the rational use of the velocity factor on both the oil and firing side of the heating surface, and the study and application of the principles of radiant heat in furnace design. Vapor Heat Economy The principle of heat exchange, especially against oil vapors, has been applied to a greater extent than ever before. The recovery of heat from oil vapors is not new. This was practiced 20 years ago or more in Europe,

Jan 1, 1928

By Henry J. Welge

The approximate methods which are now in use for calculating oil displacement from reservoirs by gas-cycling or gravity-drainage at constant gas pressure, or by water flooding, make use of fundamental relationships derived by Leverett' and Buckley and Leverett.2 The mathematical equations needed are derived by applying Darcy's law to the flowing phases, and by material balance considerations. ln general, any treatment of this type gives. for any particular exploitation time considered, a plot of oil saturation against distance in the reser-voir. The oil recovery must then be obtained by integrating in some manner the area under the plot. A useful analytical method has been derived for computing the average saturation, and hence the oil recovery. Use of this method simplifies the calculations because it makes unnecessary any numerical integrations. and even the saturation distribution plots are not needed. A further advantage of the method is that knowledge of the relative permeabilities is required only for a limited and intermediate saturation range. In both the Buckley and Leverett method and the method discussed here, a linear sand section is assumed, and in the case of gas drive the gas pressure is assumed sufficiently constant both with respect to reservoir position and time so that changes in gas density. solubility, or reservoir volume factor are negligiklle. Thus, the exploitation contemplates oil displacement as by an immiscible phase. Examples are given to illustrate how the new method can be used. INTRODUCTION AND THEORETICAL BACKGROUND This paper treats a simplified method for computing oil recovery when the oil is displaced, from the reservoir sand by a fluid which, within the limits of accuracy desired, can be assumed to be incompressible and immiscible with the oil. The method makes use of two basic relations originally developed for the case of water displacing oil. However, the case of gas displacing oil saturated with gas at a constant (or nearly constant) pressure may also be considered a displacement by an immiscible fluid. This is possible for the reason that the concentration of the gas in the oil never changes if tile pressure is fixed. consequently, any additional free gas must remain undissolved in the oil, and so must act essentially as an immiscible phase. For convenience, the cape of gas drive will be considered first. Both of the two basic relations needed refer to a linear reservoir, or one which may be somewhat idealized so that a constant cross-section is exposed to fluid flow. Further, the displacing phase is injected at one end, or face; of the reservoir, while the produced fluids are understood to emerge at one point only. which is the opposite face of the reservoir. As indicated in Fig. 1, the reservoir may he inclined by some angle 8. The first of the required equations may be derived by applying Darcy's law to both displacing and displaced phases, and subtracting the two equations. The result for water drive has been given previously, as Equation (13) of the reference by

Jan 1, 1952

By Carl F. Floe, Michael B. Bever

THE possibility that carbon may be soluble in copper to a limited extent has been recognized for over a century. The quantitative investigation of this problem, however, requires more sensitive techniques than have formerly been available. Three recent developments have made possible more accurate determinations: the vacuum-fusion method of analysis, the production of copper of high purity and the availability of high-purity refractories, particularly graphite. In addition to its obvious theoretical interest, the problem of carbon solubility in copper is of practical importance. In the production of copper and of high-copper alloys, carbonaceous covers are frequently used. If even minute amounts of carbon are dissolved, insoluble carbon oxide gases will be formed when such metals are poured under oxidizing conditions. A mechanism of this kind could well be one of the principal causes of gas porosity in casting copper-base products. REVIEW OF LITERATURE In 1823 Vivian1 raised the question as to whether copper by overpoling becomes "combined with a minute portion of carbon." Karsten2 asserted, in 1832, that carbon reduces the high-temperature strength of pure copper, so that when the carbon content has reached 0.2 per cent the metal will be brittle at a dark red heat. According to Karsten, carbon contents of o.05 per cent make it difficult to hot-work copper. He also reported that the specific gravity of copper is 8.8969 and that it increases to 8.92 58 if the copper is cemented with carbon and then melted. He emphasized the difficulty of determining analytically the small amounts of carbon present in copper. The metal was removed by wet methods and the residue considered as carbon. At Percy's request, Dick,3 in 1856, carried out various working tests on copper that had been in prolonged contact with carbon, and found that the working properties of the metal had not been affected. He also attempted to determine the presence of carbon analytically. In one experiment the copper was dissolved and the residue was fused with litharge, and in another essentially a combustion analysis was made on a copper sample. In a final experiment, a sample was dissolved and the residue subsequently subjected to a combustion analysis. Indications of as much as o.005 per cent carbon were found, but Dick considered his work inconclusive largely because of the possible interference of sulphur. Percy4 concluded, from Dick's experiments and from some experimental work of his own, that the solubility of carbon in copper had not been established with

Jan 1, 1945

By P. R., Bradley

THE Juneau gold belt is divided into ore-bands of poor definition. The most easterly workings on the , belt, those of the Alaska Gastineau Co., disclosed three separate bands: the Footwall or Ground-hog band, 70 ft. wide; the Perseverance band on which the recent mining was done, also 70 ft. wide; and the No. 2 band, 100 ft. wide. These bands, aggregating 240 ft., are found over a width of 2000 ft. Going toward the west into the adjoining Alaska Juneau ground, four bands have been found which have a total 'right-angle thickness of 755 ft. These bands are convergent in their westerly trend and terminate on the plane of Silver Bow fault. The four bands have better definition at the fault plane than at the eastern boundary line where they enter the property. -Along the property line, the width of the bands and intervening country is 1600 ft., and at the Silver Bow fault this width is reduced to 1300 ft. The distance from the eastern property line to Silver Bow fault is 2400 ft. The bands are slate or slate with metagabbro intrusions, together with gold-bearing quartz masses, stringers, and gash veins. The bands themselves are not all ore, but all commercial .ore is found within the bands. They have no uniform width either in horizontal or vertical section. The ore has no hard and fast boundary except where cut by faults, and profitable mining ceases on a vague and

Jan 1, 1929

By P. C. Hodges

WHILE there is very little romance connected with the operation of a stone quarry, yet to those who have participated in the growth and development of a business that has been a pioneer in its field and that FIG. 1.-LOCATION OF PROPERTY OF MARBLE CLIFF QUARRIES COMPANY. has been in continual operation two-thirds of a century there is bound to be a background of experience, which if properly capitalized, brings progress as well as satisfaction in its accomplishment.

Jan 1, 1936

By R. H. Hiltz

Three titanium alloys, known to provide a mechanically unstable p structure after quenching, were selected as material for a study of the Origin and nature of stress-induced transformation. Data from hardness and tensile tests were used to study the initiation of marten site and the effect of the transfornation and transformation products on the mechanical properties of B titanium, particularly the stress-strain relationships. With the exception that the materials investigated showed a natural aging reaction in the P condition, their behavior is analogous to that of' stress-transforming stainless steels. The transformation starts after initial yielding and is essentially complete just prior to .maximum loading. Once initiated, the martensite itself is capable of propagating the transformation. The deforn-ing materials show low strength, high ductility, and a high strain-hardening exponent. In metallic systems which undergo a diffusionless transformation on cooling, it is possible to produce a similar transformatiorl by plastic deformation under special conditions. Dewez' in delineating Ms temperatures for the titanium-rich end of most titanium binary systems:, established the point of intersection of Ms with room temperature for those particular alloys. Alloy compositions which would quench to mechanically unstable p were established from these data. The first investigation into the possibility of stress-induced transformation occurring in titanium met with little success. It was concluded that such a transformation in titanium was possible only under very special conditions. Continued effort in this direction, however, showed certain Ti-Mo binaries to be highly susceptible to this phenomenon. This fact was utilized by Liu to study the habit planes of martensite and by Machlin and wenig5 to study the effects of stress and plastic deformation on the P to a prime transformation in titanium alloys. The first investigation of the mechanical properties of these alloys was conducted by Holden and his coworkers at Battelle Memorial Institute.' The potentiality of the alloys i3s sheet-forming material was recognized, and the data reappeared in a survey of this type of titanium material.? The initial optimism was tempered by the difficulties in obtaining homogeneous 2i-Mo alloys in commercial-size ingots. The increasing need for good sheet-forming material kept investigation in this direction active, resulting in the development of a commercial alloy of this type.' This study was undertaken to obtain a clearer picture of the mechanism of stress-induced transformation in titanium. MATERIALS AND TEST PROCEDURE Three alloys were selected for this investigation: one a Ti-Mo alloy; another a Ti-Cr-Mo alloy, known to deform martensitically; and the third, a Ti-V alloy with an Ms below room temperature and an Md above room temperature, but known to contain w phase in the quenched condition. The compositions of these alloys are given in Table I. These alloys were cast as 5-lb experimental ingots, employing skull melting. The ingots were hot-forged into 1-in.-round bars. Two 72-in.-thick slices were cut from each bar for hardness testing; the remainder was cut into 0.252-in. tensile blanks. The tensile blanks and one hardness disc from each bar were heated in salt to a temperature 100°F above the 0 transus, held 2/2 hr, and brine quenched. X-ray analysis showed the pieces to be 100 pct 8.* *Omega cannot be distinguished from p by the technique employed. Tensile blanks were machined to size after this treatment. TO prevent transformation due to machining stresses, the shoulders and gage length were ground. True stress-true strain curves were

Jan 1, 1960

By Franklin H. Sharp, Kenneth L. Clifford

During the last few years the New Lead Belt of Southeastern Missouri has become the main source of lead in the United States. It also produces significant amounts of zinc, copper and silver. The mines are located on a narrow, mineralized trend extending southward from Viburnum, MG. for about 35 miles. The ore occurs as replacement deposits in the Bonneterre lime- stone formation which is about 1000 ft below the surface. In most of the mines, enough water is produced to supply the milling requirements without any reuse. There are dry areas, however, and at least two mills must rely on water reclaimed from their tailings lake to augment the mine water. These mills have no choice but to utilize recycled mill water.

Jan 7, 1973

By A. M. Rahm

PROBABLY the majority of red brass sand castings are judged merely on the basis of outside appearance and the quality of machined surfaces. Many castings, however, must individually withstand a hydraulic or air-pressure test before being accepted as parts of more complicated machin-ery. Finally, there remains a comparatively small group of castings intended for uses of considerable responsibility where only the highest possible characteristics of the metal are acceptable, and for these specially cast test bars are required. The shape of the cast piece from which the test bar must be detached varies greatly from one country to another. The test bar as specified in the American Society for Testing Materials Specification B62-36 is widely used by the American foundry industry. The actual test piece is at the bottom of the cast block and has a riser about six times its mass. It is obvious that this test bar has an advantage over the actual casting. The latter rarely possesses a riser of as much as 30 per cent of its own weight and that riser cannot generally be located in so convenient a manner. Therefore, the characteristics of the test bar cannot possibly correspond to those of the casting itself. It must be taken into consideration that red brass if melted and cast in the best possible manner may show a tensile strength of 40,000 lb. per sq. in. with 35 per cent elongation in 2 in. Such a test bar would indicate that the metal was nearly perfect from the viewpoint of its gas and inclusion content. Barring some accidental defect, a casting cor-responding to such a test bar could be accepted as being quite sound. However, actual specifications do not demand such high characteristics; indeed, few specifications require over 30,000 lb. per sq. in. and 20 per cent elongation, while one Federal specification demands merely 27,000 lb. per sq. in. strength and 15 per cent elongation. It is obvious that

Jan 1, 1939

By J. E. Graham, A. H. Glenn

Oil operators engaged in drilling on the Continental Shelf of Louisiana and Texas are in agreement that adverse weather and wave action are two of the greatest hazards to the safety and efficiency of their work. It was ami-pated when the offshore operations commenced that such would be the case, and experience to date has verified this assumption. Because atmospheric conditions and wave action involve tremendous amounts of energy it is highly unlikely that it will be possible to control any but the most localized weather and wave phenomena within the foreseeable future. Thus. as long as the offshore operations involve the movement of small craft and barges over exposed waters, and the transfer of personnel and heavy equipment from these craft to either fixed structures or larger craft at close quarters, the weather and wave problem will remain. Taking into consideration the persistence of the wave and weather problem and the improbability of achieving a direct solution, the Humble Oil & Refining Company, in planning its offshore campaign investigated the possibility of forecasting wave and weather conditions in order to provide warnings of dangerous conditions and increase efficiency in day-to-day planning of work. It was recognized that predictions of wave and weather conditions based on meteorology and oceanography, both geophysical sciences, are not 100 per cent accurate and application of forecasts in the offshore work was dependent on whether they provided information which was sufficiently greater in accuracy than the layman's guess to be worth the expenditure involved. During World War 11. meteorology and oceanography were used with success in reducing danger resulting from environmental conditions and increasing efficiency of operations exposed to the elements. This success was partially the result. of improvement in the scientific techniques involved and the procurement and distribution of observational data, and partially due to the large scope of the military operations which meant that a reduction of losses of a relatively small percentage of the total cost amounted to a large figure expressed in terms of dollars. Since the offshore drilling involves an extremely large financial investment, it was considered that the experience of the Armed Services in successfully employing meteorology and oceanography might be duplicated in the oil industry. In addition. the oil industry's successful experience in utilizing seismology, geology, and terrestrial magnetism; all geophysical sciences, indicated that meteorology and oceanography, also of the family of geophysical sciences and sharing their scientific assets and liabilities, might be profitably put to use. Since the immediate problem involving the sciences of meteorology and oceanography in the offshore campaign is wave action, a program was inaugurated within the Humble Oil & Refining Company during June 1947. the purpose of which was to ascertain the applicability and limitations of wave forecasting in the offshore campaign. A summary of the effective wave forecasting techniques developed during the war was prepared in the form of a forecasting manual for the Continental Shelf off Grand Isle, Louisiana, by Bates and Glenn. After completion of this manual, experimental forecasts were prepared daily over a two-month period by Graham and Thompson to determine the accuracy of the forecasts. It was considered that the accuracy of the experimental forecasts justified a more extensive test under actual operating conditions in the offshore work and the firm of A. H. Glenn and Associates was set up under the sponsorship of the Humble Oil & Refining Company to work with the Humble Grand Isle District in providing forecasts of wave and weather conditions over a one-year period. This paper discusses the service now provided to the Grand Isle District, its applicability and limitations. TYPE OF FORECASTS REQUIRED It was apparent before the commence-mence of the forecasting service that a specialized type of forecast was required. Many of the weather elements of interest to the general public, such as rain and temperature, are of minor concern to offshore operators. On the other hand, such elements as wave height and wind speed and direction are of great concern in the offshore operations since variations in wave height of a few feet in the critical range divide safe from hazardous working conditions. To be of utility. a forecasting service for the offshore work must provide detailed forecasts of the elements which affect the operation. With this in mind, it was decided that forecasts would include the following information: average wave heights to the nearest foot, wind speeds within a range of approximately 5 miles per hour, and wind directions within 221 degrees. Since the procedure for forecasting these elements involves thorough analysis of weather data, it was decided to include a generalized forecast of weather conditions such as rain and cloud cover, although these are of secondary importance.

Jan 1, 1949

By A. H. Glenn, J. E. Graham

Oil operators engaged in drilling on the Continental Shelf of Louisiana and Texas are in agreement that adverse weather and wave action are two of the greatest hazards to the safety and efficiency of their work. It was ami-pated when the offshore operations commenced that such would be the case, and experience to date has verified this assumption. Because atmospheric conditions and wave action involve tremendous amounts of energy it is highly unlikely that it will be possible to control any but the most localized weather and wave phenomena within the foreseeable future. Thus. as long as the offshore operations involve the movement of small craft and barges over exposed waters, and the transfer of personnel and heavy equipment from these craft to either fixed structures or larger craft at close quarters, the weather and wave problem will remain. Taking into consideration the persistence of the wave and weather problem and the improbability of achieving a direct solution, the Humble Oil & Refining Company, in planning its offshore campaign investigated the possibility of forecasting wave and weather conditions in order to provide warnings of dangerous conditions and increase efficiency in day-to-day planning of work. It was recognized that predictions of wave and weather conditions based on meteorology and oceanography, both geophysical sciences, are not 100 per cent accurate and application of forecasts in the offshore work was dependent on whether they provided information which was sufficiently greater in accuracy than the layman's guess to be worth the expenditure involved. During World War 11. meteorology and oceanography were used with success in reducing danger resulting from environmental conditions and increasing efficiency of operations exposed to the elements. This success was partially the result. of improvement in the scientific techniques involved and the procurement and distribution of observational data, and partially due to the large scope of the military operations which meant that a reduction of losses of a relatively small percentage of the total cost amounted to a large figure expressed in terms of dollars. Since the offshore drilling involves an extremely large financial investment, it was considered that the experience of the Armed Services in successfully employing meteorology and oceanography might be duplicated in the oil industry. In addition. the oil industry's successful experience in utilizing seismology, geology, and terrestrial magnetism; all geophysical sciences, indicated that meteorology and oceanography, also of the family of geophysical sciences and sharing their scientific assets and liabilities, might be profitably put to use. Since the immediate problem involving the sciences of meteorology and oceanography in the offshore campaign is wave action, a program was inaugurated within the Humble Oil & Refining Company during June 1947. the purpose of which was to ascertain the applicability and limitations of wave forecasting in the offshore campaign. A summary of the effective wave forecasting techniques developed during the war was prepared in the form of a forecasting manual for the Continental Shelf off Grand Isle, Louisiana, by Bates and Glenn. After completion of this manual, experimental forecasts were prepared daily over a two-month period by Graham and Thompson to determine the accuracy of the forecasts. It was considered that the accuracy of the experimental forecasts justified a more extensive test under actual operating conditions in the offshore work and the firm of A. H. Glenn and Associates was set up under the sponsorship of the Humble Oil & Refining Company to work with the Humble Grand Isle District in providing forecasts of wave and weather conditions over a one-year period. This paper discusses the service now provided to the Grand Isle District, its applicability and limitations. TYPE OF FORECASTS REQUIRED It was apparent before the commence-mence of the forecasting service that a specialized type of forecast was required. Many of the weather elements of interest to the general public, such as rain and temperature, are of minor concern to offshore operators. On the other hand, such elements as wave height and wind speed and direction are of great concern in the offshore operations since variations in wave height of a few feet in the critical range divide safe from hazardous working conditions. To be of utility. a forecasting service for the offshore work must provide detailed forecasts of the elements which affect the operation. With this in mind, it was decided that forecasts would include the following information: average wave heights to the nearest foot, wind speeds within a range of approximately 5 miles per hour, and wind directions within 221 degrees. Since the procedure for forecasting these elements involves thorough analysis of weather data, it was decided to include a generalized forecast of weather conditions such as rain and cloud cover, although these are of secondary importance.

Jan 1, 1949

By Michael B. Bever, Carl F. Floe

he possibility that carbon may be soluble in copper to a limited extent has bten recognized for over a century. The quantitative investigation of this problem, however, requires more sensitive techniques than have formerly been available. Three recent developments have made possible more accurate determinations: the vacuum-fusion method of analysis, the production of copper of high purity and the availability of high-purity refractories, particularly graphite. In addition to its obvious theoretical interest, the problem of carbon solubility in copper is of practical importance. In the production of copper and of high-copper alloys, carbonaceous covers are freauerltlv used. If even minute amounts of carbon are dissolved, insoluble carbon oxide gases will be formed when such metals are poured under oxidizing conditions. A mechanism of this kind could well be one of the principal causes of gas porosity in casting copper-base products. Review of Literature In 1823 Vivian1 raised the question as to whether copper by overpoling becomes "combined with a minute portion of carbon." Karsten2 asserted, in 1832, that carbon reduces the high-temperature strength of pure copper, so that when the carbon content has reached 0.2 per cent the metal will be brittle at a dark red heat. According to Karsten, carbon contents of 0.05 per cent make it difficult to hot-work copper. He also reported that the specific gravity of copper is 8.8969 and that it increases to 8.9258 if the copper is cemented with carbon and then melted. He emphasized the difficulty of determining analytically the small amounts of carbon present in copper. The metal was removed by wet methods and the residue considered as carbon. At Percy's request, Dick,3 in 1856, carried out various working tests on copper that had been ill prolonged contact with carbon, and found that the working properties of the metal had not been affected. He also attempted to determine the presence of carbon analytically. In one experiment the copper was dissolved and the residue was fused with litharge, and in another essentially a combustion analysis was made on a copper sample. In a final experiment, a sample was dissolved and the residue subsequently subjected to a combustion analysis. Indications of as much as 0.005 per cent carbon were found, but Dick considered his work inconclusive largely because of the possible interference of sulphur. Percy4 concluded, from Dick's experiments and from some experimental work of his own, that the solubility of carbon in copper had not been established with

Jan 1, 1946

By Carl F. Floe, Michael B. Bever

he possibility that carbon may be soluble in copper to a limited extent has bten recognized for over a century. The quantitative investigation of this problem, however, requires more sensitive techniques than have formerly been available. Three recent developments have made possible more accurate determinations: the vacuum-fusion method of analysis, the production of copper of high purity and the availability of high-purity refractories, particularly graphite. In addition to its obvious theoretical interest, the problem of carbon solubility in copper is of practical importance. In the production of copper and of high-copper alloys, carbonaceous covers are freauerltlv used. If even minute amounts of carbon are dissolved, insoluble carbon oxide gases will be formed when such metals are poured under oxidizing conditions. A mechanism of this kind could well be one of the principal causes of gas porosity in casting copper-base products. Review of Literature In 1823 Vivian1 raised the question as to whether copper by overpoling becomes "combined with a minute portion of carbon." Karsten2 asserted, in 1832, that carbon reduces the high-temperature strength of pure copper, so that when the carbon content has reached 0.2 per cent the metal will be brittle at a dark red heat. According to Karsten, carbon contents of 0.05 per cent make it difficult to hot-work copper. He also reported that the specific gravity of copper is 8.8969 and that it increases to 8.9258 if the copper is cemented with carbon and then melted. He emphasized the difficulty of determining analytically the small amounts of carbon present in copper. The metal was removed by wet methods and the residue considered as carbon. At Percy's request, Dick,3 in 1856, carried out various working tests on copper that had been ill prolonged contact with carbon, and found that the working properties of the metal had not been affected. He also attempted to determine the presence of carbon analytically. In one experiment the copper was dissolved and the residue was fused with litharge, and in another essentially a combustion analysis was made on a copper sample. In a final experiment, a sample was dissolved and the residue subsequently subjected to a combustion analysis. Indications of as much as 0.005 per cent carbon were found, but Dick considered his work inconclusive largely because of the possible interference of sulphur. Percy4 concluded, from Dick's experiments and from some experimental work of his own, that the solubility of carbon in copper had not been established with

Jan 1, 1946

By L. O. Howard

The practice of using acid-lined converters at the plant of the Old Dominion, Copper Mining & Smelting Co. was discontinued early in January, 1913, and replaced by basic-lined converters. The new equipment consists of one electrically operated 12-ft. upright converter stand and two basic-lined shells for same. These shells are provided with twenty-four 1 1/4-in. tuyeres. The mouths are 5 ft. in diameter. Owing to the fact that there is no bedding system or other large storage capacity between the mine and the smelter, the furnaces must handle as fast as produced ore and concentrates, which may vary considerably from day to day, both in tonnage and copper content. Consequently the converter is often crowded to its utmost capacity by the frequent fluctuations in the daily matte supply. From the foregoing, it will be seen that in no way can the 'converter be favored by running light charges or by transferring to it from other stands in operation. Neither can it regularly be allowed to cool between blows, and only occasionally can it be run at as low a temperature as might be wished. No copper precipitate or other foreign material high in copper is available to help out the tonnage. Repairs and alterations or the removal of defective tuyeres must wait until such time as a slight falling off in.the matte supply allows the converting operations to ease up. These variable conditions all combine to interfere with the systematic operating of the converter. The first 12-ft. shell was blown in on Jan. 6, 1913, and ran until June 27, 1913, when it was removed to patch the brick. A record of operations covering this period follows: Shell No. 1. First Campaign, Jan. 6,to June 27, 1913 Commenced blowing............................Jan. 6, 1913. Taken off stand for patching.....................June 27, 1913. Total blowing time..........................2,689 hr. 40 min. Total number of, blows made.............................. 664 Average time of blow............................ 4 hr. 3 min. Tons matte charged.................................. 18,157 Average copper content of matte................ 43.9 per cent. Average time blowing one ton. copper................ 22.5 min. Total copper made............................... 7,250 tons

Jan 1, 1915

Discussion of the paper of S. E. Bretherton, presented at the Butte meeting, August, 1913, and printed in Bulletin No. 80, August, 1913, pp. 1481 to 1487. S. E., BRETHERTON, San Francisco, Cal.:-Since preparing my paper, our chemist, F. L. Wilson, has been experimenting with Leadville, Colo., oxidized zinc ore and Leadville zinc sulphides containing lead, operating upon 40-1b. lots at a time. His results on Leadville sulphides are as follows: The raw ore contained a trace of gold, 5.04 oz. of silver, 19.1 per cent of zinc, and 7.24 per cent of lead. After roasting the ore contained a trace of gold, 5.72 oz. of silver, 0.75 per cent of copper, 21.7 per cent of zinc, and 8.29 per cent of lead. The loss in weight by leaching was 38.8 per cent. The extraction was 42.8 per cent of the copper, 80.6 per cent of the zinc, 7.1 per cent of the lead, 0.64 per cent of the silver, and no gold. The little .silver that is extracted would be thrown down with the copper when precipitating it from the zinc and both thrown hack into the residue to be smelted. There would be no trouble in smelting the residue with nearly all the sulphur eliminated and containing less than 7 per cent. of zinc. On zinc carbonates containing silicates the results are not satisfactory. H. O. HOFMAN, Boston, Mass. (communication to the Secretary*) :¬The paper by Mr. Bretherton upon the application of ammonia and carbonic acid to the recovery of zinc as oxide from roasted sulphide ore is of interest to me, as the first installation of the Schnabel process for the extraction of zinc from a mixture of zinc oxide, lead oxide (with some cupric oxide), and pellets of enriched lead, produced in steaming liquated zinc-silver-lead crust of the Parkes process, was made at Lautenthal, Harz mountains, where I was chemist. In that capacity I carried out numerous experiments on the Schnabel process, was active in the erecting of the plant, and later had charge of it. After the Lautenthal plant had been in operation for some time a similar one was built at Hoboken-les-Anvers, but both have been abandoned, as the wet process could not compete with the distillation of the liquated zinc-silver-lead crust, now used universally in the Parkes process.

Jan 11, 1913

By T. H. Aldrich

(San Francisco Meeting, October, 1911.) THERE are two conditions generally prevailing upon the earth-those within atmospheric influence, tending towards oxidation, and those away from atmospheric influence, tending towards reduction. Practically all mineral substances from mines of any depth are in a reducing condition. Since the cyanide process, in order to dissolve silver or gold, requires that the prevailing conditions under which it operates shall be oxidizing, and the materials usually acted upon being of a reducing character, it becomes necessary to supply oxygen to the solution carrying the cyanide. This oxygen is usually supplied through the medium of dissolved air in the solution, or through the medium of various chemical compounds, which upon combining with the solution or the ore give off a part of their oxygen. Strange as it may seem, practically all mineral substances are partly soluble in water, especially water carrying alkali or cyanide. The greater the surface exposed and the finer the material is ground, the greater will be the rate of dissolving of the reducing agents from the ore into the cyanide solution. In most cases, if the solution carrying the ore particles is agitated with air, the air will dissolve into the solution faster than will the reducing-agents; but in some cases the reducing-agents will dissolve more rapidly on account of easy solubility or greater surface exposed. It is a dissolving race between the oxygen from the air and the reducing-agents from the ore, and if the reducing-agents predominate, cyanide will not dissolve the gold from the ore. In many cases it will dissolve some of the gold, because in a mass of irregular shape some of the gold particles might be exposed upon the outside surface of a particle of rock;' but if the solution had to penetrate through cracks, the side-walls of which were lined with reducing-agent-

Feb 1, 1912

By N. A. Ziegler

THE chief difficulty in determining oxygen in steels is its tendency to form a variety of compounds. Almost every element, found as an ingredient in steels, maybe expected to be present as an oxide. Some of these oxides have widely differing properties, and consequently behave differently when attempts are made to reduce them by the vacuum fusion method. As I pointed out in a paper published in the Transactions of the A.S.S.T., Vol. 20, No. 1, many experimenters are spending considerable time and effort in attempting to deter¬mine the degree of completeness of the above reactions, and hold different opinions on the matter. In studying this subject the following table, taken from Hodgman and Lange's "Handbook of Chemistry and Physics" may be used as a guide.

Jan 1, 1933

By Pradeep K. Rohatgi, Clyde M. Adams

Dendritic aggregate of ice formed on freezing of aqueous soluitions has been studied. Chlorides of sodium, potassiutn, lithiunz , and hydroget1 were used as solutes. The spacing between ice platelets or den-drites was experimenlally found proportzonal to the square root of freezing time when the freezing rate was constant from beginrting to end of solidification; the constant freezing rates were obtained during freezing of small droplets of aqueous soliitions surrounded by relatively large heat sinks. The transverse growth velocity of the ice platelets is proportional to the square root of the freezing rate. During unidirectional freezing from a constant temperuture chill, the solution at each location is subjected to a spectrum of freezirtg rates. The freezing rate is ini- FREEZING of solutions has been a subject of investigation in many disciplines. Aqueous solutions offer the advantage of transparenty; their study is of special significance due to the increasing interest in freezing processes for desalination. In addition dendritic solidification of aqueous solutions is in many ways analogous to freezing of metallic solutions. Aqueous solutions of most ionic salts freeze with tially low, passes through a maximum, and then decreases until solidificatimz is complete. The den-drite spacing increases linearly with the distance from the chill surface; it is inversely profiortional to the square root of the maximum freezing rate. The dendrite spacings in the two systems (the constanl freezing rate and the varying freezing rate) are equal, when the maximum freezing rate of the varying freezing rate system equals the average freezing vale of the constant freezing rate system. Mass transport in interdendritic liquid duriug solidificatiotz is analyzed; the experimental observations indicate that maximum concentration difference (AC) and supercooling (AT) in the interdendritic liquid are indepexdent of freezing rate. the separation of practically pure ice crystals from the liquid phase; with very few exceptions there is no solid solubility of ionic salts in ice. As an ice crystal grows there is rejection of solute from the moving interface into the liquid. Since the rejected solute moves primarily by diffusion, concentration gradients are established in the liquid. The highest solute concentrations are found in liquid immediately adjacent to liquid-solid interfaces and lowest concentrations farthest from the interface. Two-phase equilibrium obtains only at the solid-liquid interface; at other locations the liquid becomes supercooled because temperature gradients are negligible compared to concentration gradients. This is an immediate consequence of the fact that thermal diffusivities are considerably higher than mass diffusivities.

Jan 1, 1968

By W. N. Marchant, P. T. Brooks, P. B. Altringer, R. O. Dannenberg

The US Department of the Interior, Bureau of Mines conducted laboratory tests to devise a process for recovering a marketable grade of tungsten from the brine of Searles Lake, Calif. The brine contains only 56 ppm W (70ppm WO3). Using ion exchange resins synthesized by USBM chemists, 98% of the tungsten was extracted from the brine and 92% of the tungsten was recovered as a marketable iron-tungsten concentrate containing 44% tungsten as tungsten trioxide. Although major technical problems have largely been resolved, research is progressing to escalate testing in a process research unit to provide more reliable data for an economic appraisal

Jan 1, 1980

By L. S. McNickle

Commonly accepted maintenance methods are being outdated by the rapid acceptance and use of more complicated hydraulic circuitry on modern mining equipment. It is no longer adequate to use the maintenance program to merely repair or sustain equipment operation. Ever increasing operating costs place a huge premium on lost production time. It has, therefore, placed the maintenance programs in the position of being required to alleviate equipment malfunctions on production shifts and still attain the maximum unit life from each component part. Ireland mine of Hanna Coal Co., which operates two production shifts and one maintenance shift per day, performs hydraulic maintenance with a plan that is geared to assure the bulk of work being handled on the midnight or maintenance shift. Production is thus allowed to continue without interruption from major hydraulic component malfunction. The plan is called selective maintenance because the specific part to be worked on and the time the work is to be accomplished are selected according to a definite plan.

Jan 10, 1961