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The officers and staff of the Petroleum Division are the servants of the members, and to the extent that the wishes of the members are made known and are practicable they will be carried out. The tentative plans outlined here are in general accord with previous custom, but modified by suggestions received recently from various members. The advice of all members is solicited, and it is hoped that the general expression on matters of policy can soon be facilitated by circulation of a questionnaire. Plans for two mid-year meetings of the Petroleum Division and for participation in the annual meeting at New York were inaugurated at the last annual meeting and are being carried forward as rapidly as possible in the belief that an early start will increase the possibility of finding the best available program material and permit the careful preparation, review, editing, and advance discussion of papers. While a number of papers have already been solicited, both members and nonmembers are hereby invited to submit additional papers, with the assurance that such papers will be given just as favorable consideration as the papers that have been requested. Mid-year meetings will be held at about the same time both in the Mid-Continent and California. The time will be selected if possible to coincide with the visits of President Lovejoy, who expects to be in California the last of September and in Texas early in October. Fort Worth, Dallas and Austin have been suggested for the Mid-Continent meeting. The Pacific Coast meeting will be held at Los Angeles. It is to be noted particularly that a Pacific Coast meeting was waived last year in favor of the annual meeting of the American Petroleum Institute, which was held at Los Angeles for the first time in nine years. It is hoped, and it was the understanding at the time among a number of individuals interested in both organizations, that in view of this action of the Petroleum Division the industry will give more than the usual support to the A.I.M.E. meeting this year. Ultimate Recovery is being considered as the keynote topic for the mid-year meetings. In view of trying financial conditions combined with an exceptionally high current potential rate of production, it is natural that the attention of the industry should be focused upon means of controlling production and reducing cost of operation. It seems that the Petroleum Division of the A.I.M.E., as a professional group, might

Jan 1, 1936

The officers and staff of the Petroleum Division are the servants of the members, and to the extent that the wishes of the members are made known and are practicable they will be carried out. The tentative plans outlined here are in general accord with previous custom, but modified by suggestions received recently from various members. The advice of all members is solicited, and it is hoped that the general expression on matters of policy can soon be facilitated by circulation of a questionnaire. Plans for two mid-year meetings of the Petroleum Division and for participation in the annual meeting at New York were inaugurated at the last annual meeting and are being carried forward as rapidly as possible in the belief that an early start will increase the possibility of finding the best available program material and permit the careful preparation, review, editing, and advance discussion of papers. While a number of papers have already been solicited, both members and nonmembers are hereby invited to submit additional papers, with the assurance that such papers will be given just as favorable consideration as the papers that have been requested. Mid-year meetings will be held at about the same time both in the Mid-Continent and California. The time will be selected if possible to coincide with the visits of President Lovejoy, who expects to be in California the last of September and in Texas early in October. Fort Worth, Dallas and Austin have been suggested for the Mid-Continent meeting. The Pacific Coast meeting will be held at Los Angeles. It is to be noted particularly that a Pacific Coast meeting was waived last year in favor of the annual meeting of the American Petroleum Institute, which was held at Los Angeles for the first time in nine years. It is hoped, and it was the understanding at the time among a number of individuals interested in both organizations, that in view of this action of the Petroleum Division the industry will give more than the usual support to the A.I.M.E. meeting this year. Ultimate Recovery is being considered as the keynote topic for the mid-year meetings. In view of trying financial conditions combined with an exceptionally high current potential rate of production, it is natural that the attention of the industry should be focused upon means of controlling production and reducing cost of operation. It seems that the Petroleum Division of the A.I.M.E., as a professional group, might

Jan 1, 1936

By L. H. JEFFRIES

In the mining operations of The Canyon Corp., Deadwood. S. D., the use of mucking machines has been of definite advantage. The type used is that which depends upon the traction of the motor-driven wheels to crowd the dipper into the muck pile, while the car in which the muck is received is coupled to the mucker and moves forward or back with it. This general arrangement is entirely satisfactory on a substantially level track. The ores which occur in this district are a replacement of dolomite and the beds are now tilted to an inclination of about 7-1/20. In our operations it is necessary to drive inclines down-hill on this slope, which makes a difficult hand-mucking job even if water were not present. With these facts in mind, an attempt was made to use the mucking machine for driving down the in- cline, but as expected, the traction was insufficient to handle the machine and the necessary car. The means used to correct this condition will perhaps impress most readers as too complicated and cumbersome to effect any economy, but the idea may be of service to some who have a similar condition. After considering several s

Jan 1, 1940

By Don H. Baker

THE need for new or improved refractory materials has caused metal phosphides to be given renewed scrutiny. Some metal phosphides show high-temperature inertness, are exceptionally hard, and exhibit a marked resistance to chemical attack. Various metal phosphides have been prepared for study by direct combination of the elements,'-' by reaction of metal or metal compounds with phosphine or phosphorus trichloride,'"' by thermal decomposition of a metallic phosphate or phosphite,"-'8 and by molten salt electrolysis.19 Electrolytic preparation of phosphides of titanium, manganese, and chromium from their oxides is reported in this paper. An externally heated 3-in.-ID by 6-in.-deep graphite cell, that served as the anode as well as a container for the electrolyte, was used in these investigations, and a suspended, centrally positioned graphite rod served as the cathode. A closely fitting silicon carbide furnace liner minimized atmospheric oxidation of the crucible. Electrolyses were performed for predetermined periods and current settings. Preliminary research had indicated the more efficient current and potential settings that could be used. Upon completion of the deposition period, the deposit was hot-stripped from the cathode. The mass of crystalline deposit, plus occluded and adhering salt, was crushed to minus 10 mesh and hot-leached in dilute hydrochloric acid. The leached crystalline material was water-washed, dried, and sampled for analysis. Products were identified by X-ray diffraction and standard analytical procedures. Electrochemical studies were initiated to establish the optimum conditions necessary to produce manganese phosphide (MnP), titanium phosphide (Tip), and chromium phosphide (CrP). Among the factors studied were the operating temperature, the imposed current, and the electrolyte system. If the temperature, or imposed current, was too high, deposition of phosphorus resulted, and if either were too low, partially reduced lower oxides were deposited. The operating conditions established for repetitive high-quality production of metal phosphides of the MP structure are presented in Table I. The metal phosphide crystals varied in size, but all had a definite metallic appearance. Typical are the crystals of CrP shown in Fig. 1. Evaluation data and analysis of the crystals are presented in Table 11. Efforts to measure resistivity of these three compounds over the temperature ranges of 250o to 400°K were hampered by the small physical size of the crys-

Jan 1, 1968

By L. F. Mondolfo, B. E. Sundquist

The crystallographic orientation relationships resulting when lead is nucleated from the liquid by Ni, Cu, Ag, and Ge were determined. For each nucleating agent several definite orientatioz relationships were found. These relationships seemed to be controlled by good symmetry relations and low crystallographic disregistry between mating planes. For any given nucleating agent the under colling for nucleation was found fairly constant and independent of the orientation relationship and consequent disregistry. It was also found that, upon re melting and refreezing the Pb, the orientation relationship was changed. These findings prove that crystallographic disregistry is not the controlling factor in heterogeneous nucleation from the liquid. The results of this investigation tend to confirm the theory presented in a preceding paper that heterogeneous nucleation starts with the formation of an adsorbed layer of nucleated metal on the nucleat-ing impurity. Evidence is given that cavities in the nucleating agent act as centers of nucleation. IT has long been known' that solid extraneous particles are active in catalyzing phase transformations that occur in a system, particularly condensation and crystallization. It is well established that these heterogeneities act as catalysts by providing surfaces upon which nuclei of the precipitating phase can form with activation energies smaller than those required for homogeneous nucleation. Numerous investigations have shown that in this process of heterogeneous nucleation: a) the nucleus forms with one, or several, definite crystallographic orientation relationships with the nucleating phase2-4 and b) that there is a small range of undercoolings or super saturations characteristic of the nucleation of a given solid on a given Substrate.5-10 Turnbull and vonnegut11 have developed a theory based on theories developed by Volmer12 and Turn-bull and Fisher1= for heterogeneous nucleation from gases and liquids, that relates the super saturation or undercooling required for nucleation to the dis-registry between the lattices of the nucleus and the nucleating agent. This theory predicts that nucleation should occur with the orientation relationship between the nucleus and nucleating agent that minimizes the disregistry. Further, it predicts that the undercooling or super saturation necessary for nucleation should be a function of the disregistry. Numerous investigations have dealt with the orientation relationships resulting from the condensation of vapors onto crystalline solid substrates2,3 and a few with the nucleation of one phase by a second phase in solidification4,14. Others have dealt with the supersaturation8-10 and undercooling5-7 associated with nucleation in condensation and solidification respectively. However, there is virtually no report that gives both of these factors for the same system. In this investigation a study was made of the undercoolings and orientation relationships resulting when Pb is nucleated from the liquid by Ni, Cu, Ag, and Ge. It was the purpose of this investigation to check the Turnbull-Vonnegut theory, i.e., the importance of crystallographic disregistry between nucleating catalyst and nucleated metal. The results indicate that disregistry is not an important factor in nucleation and that the nucleation process is probably somewhat more complex than current theories suggest. EXPERMENTAL PROCEDURE Small single crystals of nickel, copper, silver, and germanium were prepared from materials of four to five nines purity, and the Pb used was also 99.999+ pet pure. Cu and Ag single crystals were prepared by sealing small chips of Cu or Ag in an evacuated quartz capsule and heating the capsule at 2000°F for 1 hr before cooling. Nickel crystals of 200 diam were also prepared in evacuated quartz capsules, but melting was done by heating the capsules in an oxy-acetylene flame for a few minutes. These spheres were invariably polycrystalline so

Jan 1, 1962

By Rush Greenslade

The oil and gas lease is the basic contract of the oil and gas industry; it is the foundation stone upon which the producing industry, particularly, is based. As the industry is precarious and highly speculative, the foundation contract should be of the utmost integrity and certainty. But right there an anomaly exists; the oil and gas lease is the most obscure, most uncertain, doubtful contract in the realm of law today. That is a condition that must be considered when taking oil and gas leases, and when buying, selling, and holding them. It may fairly be asked why should this industry rest upon so insecure a foundation. Why should not the oil industry rest upon the contract that is the basis of all industry, the warranty deed? There are many contributing reasons, but the principal one is business expediency. The Anglo-Saxon idea of ownership of land is that every land owner owns from the center of the earth to the sky—all that is above and all that is below—consequently the oil and gas are owned by the person who owns the surface. That idea is not exactly true with reference to oil and gas, for many states have adopted the doctrine that oil and gas are like wild animals; they are fugacious and migratory and belong to the man that traps them. But, except for that doctrine, we believe that oil and gas are owned by the owner of the surface, wherein we differ from the Latin-American countries where the mineral rights are owned by the government. The United States was settled largely by homesteading. The owners of land were, in the main, farmers, who did not have the means or the faith to drill for oil or gas. The operators or speculators did not want to buy the land on the mere possibility of finding oil; hence a compromise resulted by which the land owner gave the speculator or the operator what he called an oil and gas lease, or a right to go upon his land and drill for oil and gas. What is supposed to be the first oil lease placed on record reads as follows: Agreed this 4th day of July, a.d. 1853, with J. D. Angier of Cherrytree township in the county of Venango Pennsylvania that he shall repair up and keep in order the old oil springs on land in said Cherrytree township, or dig and make new springs, and the expense to be deducted out of the proceeds of the oil, and the balance, if any, to be

Jan 1, 1924

A. O. GATES, Salt Lake City, Utah (communication to the Secretary*).-The writer is delighted by the results shown in Mr. Bell's paper, which prove in an experimental way different from that followed by the writer' that "the work clone in crushing is proportional to the surface exposed by the operation," per Rittinger's Law. Mr. Bell's work was all clone in commercial types of crushing machines, while my work was clone in a testing machine; his work represents fully one hundred times the expenditure and time that my work represented; a great number of tests were made by his organization to determine single points, while I was obliged to depend on the general trend of a curve for results; we agree absolutely that "Kick's law," for which Mr. Stadler was sponsor, does not apply to rock crushing. While my work indicated the reliability of Rittinger's theory, Mr. Bell's work clearly establishes the reliability and makes it Rittinger's law.

Jan 5, 1917

By J. J. Gilman

RECENT experiments have shown that the mar-tensite reaction in a standard tool steel is influenced by the history of the reacting austenite. The martensite reaction proceeds to a given extent at a higher temperature in austenite formed from an annealed spheroidal structure than it does in austenite formed from tempered martensite: that is to say, a prequench lowers the temperature range of the martensite reaction in this steel. Furthermore, a prequench alters the appearance of the martensite as compared to martensite formed from "virgin" austenite. The steel used for this work was a manganese nondeforming tool steel of the following composition: C, 0.85 pct; Mn, 1.43; Si, 0.23; Ni, 0.12; Cr, 0.59; and W, 0.59. A piece from a rolled bar was forged to Vz in. sq and annealed to a spheroidal structure. Disks 1/8 in. thick were used in the experiments. Several sets of the specimens were prepared and austenitized in lead at 1475°F. Three sets were held at 1475°F for 15 min, quenched in water, and immediately reheated to 1475°F. After this quench the three sets were held for 5 min, 30 min, and 3 hr, respectively, at 1475°F and then the individual specimens in each set were quenched in molten baths to 325", 300°, and 275ºF, respectively, and held for 15 sec. Immediately after the quenching treatments? the specimens were tempered at 600°F for 30 sec to darken the martensite and then were quenched in water. The holding times were short enough to avoid isothermal transformation. Three other sets of specimens were given the same final quenching treatments as the first three, but they were austenitized at 1475°F for 20 min, 35 min, and 3 hr and 15 min, respectively, without an intermediate water quench. The two individual specimens from each set were quenched together in order to eliminate quenching errors. Several experiments were run in this way but only the six sets referred to are described in detail because they all yielded essentially the same results. By means of the stated heat treatments the martensite reaction was investigated for: 1—austenite formed from an annealed structure, and 2— austenite formed from tempered martensite. The martensite reactions of the two types of austenite differed significantly. This is shown by Figs. 1 and 2. Comparison of the photographs on the left in Figs. 1 and 2 with those on the right shows that less martensite was formed by a quench to a given temperature from prequenched austenite than from austenite formed from an annealed structure, that is, the prequench suppressed the martensite reaction. The effect was observed for specimens austenitized 20 min, 35 min, and 3 hr and 15 min. A comparison of Figs. 1 and 2 shows that the martensite reactions in both sets of specimens occurred at lower temperatures with increased austenitization time. This was caused by the increased dissolution of residual carbides with time at 1475°F. However, the difference in amount of martensite formed in prequenched austenite as compared to virgin austenite was approximately the same for all three austenitization times. One further observation should be noted. The needles of the martensite formed from virgin austenite are somewhat longer on the average and show less of a tendency to cluster than those of martensite formed from prequenched austenite. This causes the martensite on the right in Figs. 1 and 2 to have a more acicular appearance than the martensite on the left. Since the sets of specimens used in this work were austenitized for identical total lengths of time and the effect of a prequench on the martensite reaction existed for specimens held at the austenitizing tem-

Jan 1, 1953

By E. W. Pehrson, J. W. Furness

THE five charts presented here- with are part of an original group prepared by the U. S. Bureau of Mines showing the international trade in the principal metals and metallic ores. Charts 011 anti- mony, chromite, copper, lead, manganese, mercury, nickel, tin, tungsten, and zinc were published in the February, 1936, issue of the Engineering and Mining Journal. Those shown here include bauxite, aluminum, iron ore, pig iron, and the platinum-group metals.

Jan 1, 1936

By C. R. Kuzell

Although furnaces constructed of refractory brick have been operated for many decades, there has always been an unfulfilled desire by the operators for a less arduous and more satisfactory method of patching weak spots and burned-out zones in order to postpone and to effectively extend the termination of a furnace campaign. Not only has this desire frequently arisen when small spots have approached incipient failure while the furnace structure as a whole was still in good condition, but also when larger areas showed signs of needing replacement. The available methods have been arduous, sometimes dangerous, inefficient with respect to the life of new refractory material used, and nearly always have necessitated interruption of the continuity of the furnace operations and therefore reduction in furnace production during the period of time required for the repair work. Most of these older methods have involved the replacement of masonry by refractory shapes in the weakened areas. Many attempts have been made to develop a method of patching the burned-out areas by spraying granular refractory material upon old surfaces. While some success has been attained in attempts to renew the grooved, corroded side walls and fettling, and the edges of hearths, there have been no known successful applications of the spraying method in patching the underside of arches of operating furnaces. The method developed recently at the Clarkdale smelter of the United Verde Branch of Phelps Dodge Corporation, at Clarkdale, Aria., and described in this paper, has been found to be not only convenient and successful with respect to patching vertical or inclined surfaces, but has met with a marked degree of success in patching the parts of furnace arches that are exposed to flame, the successful result being obtained without interruption or interference with the continuity of furnace operations. It may be described as a method of renewing the interior refractory surfaces of operating furnaces by pneumatic spraying of an aqueous suspension of finely divided. particles of refractory material. It has been used

Jan 1, 1944

By Michael J. Messel

THE critical shortage of asbestos fiber in the world today brings to the foreground the question of locating and developing new deposits. The object of this paper is to discuss some of the more important factors which should be considered in the examination and valuation of a new asbestos enterprise. Some of the more important uses of asbestos fiber are for textiles, heat insulators, building materials, filters and a series of other uses. The properties of this mineral, such as fibrous structure, color, strength, silkiness and flexibility, coupled with resistance to fire, certain chemical action and decay make its application unique for certain industrial uses which consume over 500,000 tons annually. These same unique properties which make this mineral so valuable also make a deposit one of the most difficult to appraise accurately, because of the many undeterminable and varying factors which must be considered before a deposit can properly be termed commercial. The majority of the asbestos fiber today, having the above mentioned properties, is sold by grades which are based on fiber length. Present day fiber prices vary over a wide range from $800 to $225 for crude fibers and $300 to $20.00 per ton for milled grades. For valuation purposes a careful study should be made of existing fiber prices and markets. EXAMINATION OF DEPOSITS In carrying out prospecting and examination of a deposit, considerable caution is required to get the necessary information in the form that will have the most value for the final determination. There are two main classes of asbestos fibers, chrysotile and the amphiboles, the chrysotile being, by far, the most important both in abundance and uses. This paper will stress mainly chrysotile deposits, however, the amphiboles have many important uses, especially amosite and crocidalite. Their valuation presents special problems as other factors may be involved, especially as they are not graded according to any well defined and adopted standard but usually according to the use for which they are being supplied. Most chrysotile deposits occur in two main types of rock, (I) mainly in basic igneous, such as dunite and peridotite, (2) to a lesser extent in sedimentary rocks, such as dolomite and limestone. All of these require a certain degree of metamorphism to be favorable to asbestos formation. Approximately 90 pct of the asbestos deposits are derived from serpentinization of dunite or peridotite, whereby the magnesiumsilicate olivine was altered to hydrous magnesium-silicate serpentine. Under certain favorable geological conditions, this serpentine takes a fibrous form having a definite crystal structure, probably due to molecular rearrangement, and is known as chrysotile. The fiber veins are usually ir-

Jan 1, 1947

By W. P. Sykes

TUNGSTEN serves mankind in two major roles. The first of these is represented by the tungsten filament of the incandescent electric lamp, a common article of commerce. In the field of hard alloys it plays its second substantial part. A fortunate combination of physical properties in this metal ac- counts for its efficient service as a source of illumination. Tungsten melts at about 3400°C, has a relatively low vapor pressure and at the same time sufficient strength, both hot and cold, to serve satisfactorily as filaments, which may range in diameter from 0.060 to 0.0005 in. In the early days of the incandescent lamp, the pioneers realized the importance of using a substance of high melting point for the source of light. The metals osmium (mp approx. 2700°C) and tantalum (mp approx. 2850°C) were both employed to some extent. Tantalum actually attained some commercial importance in this field because it could be drawn into small wires of appreciable length. DUCTILE TUNGSTEN WIRE Before the year 1908, tungsten was considered a nonductile metal, since no one had succeeded in overcoming the brittleness so typical of the unworked metal at room temperature. The methods employed today in producing ductile tungsten wire were developed over a period of years. The process was largely determined by the exceedingly high temperature required to melt this metal. Even today the difficulties involved in producing an appreciable quantity of pure

Jan 1, 1953

By William H. Shockley

Though China has been widely explored by mining engineers during the past dozen years, comparatively little has been published concerning its mineral resources. The few moilographs scattered through the transactions of various societies contain far less information than the private reports made to the numerous syndicates which have sent out engineers. The best general account of the geolopy and mineral resources of China is to be found in the works of von Richthofen,' a remarkably gifted observer. The observations recorded here in this paper were made in the service of the Pekin Syndicate (which has kindly given me permission to publish them), during the first months of 1898, among the coal- and iron-fields of southeastern Shansi. This is one of the largest anthracite-regions known, the area being

Jan 1, 1904

By Walter Crafts, C. M. Offenhauer

IN a previous study' of the carbide phase of chromium steels, it was shown that chromium carbide (Cr7C3) is a more stable carbide than cementite (Fe3C) at tempering temperatures above about 500°C. in quenched steels containing from about r1to 7.5 per cent chromium. Below this temperature the carbide phase was found to consist of cementite in all of the steels examined. In the present investigation it was found that a similar change in the carbide phase takes place in molybdenum and in chromium-molybdenum steels at approximately the same tempering temperatures. The approximate ranges of occurrence of the alloy carbides Cr7C3, Cr4C, and Mo2C have been determined in steels containing up to 5 per cent chromium, 1 per cent molybdenum and 0.60 per cent carbon. The experimental steels were made in small high-frequency furnaces from Armco ingot iron, low-carbon ferrochromium and calcium molybdate and were poured into 2-in. ingots, which were forged to 1-in. round bars. Sections of the bars were heated to the carbide-solution temperature and cooled rapidly to induce austenite transformation at relatively low temperatures. The steels were subject to some segregation, therefore comparatively high temperatures were necessary to dissolve all of the carbides. The microstructure of the quenched specimens was examined to verify the belief that the carbides had been dissolved, and also to determine the nature of the nonmartensitic structure of incompletely hardened steels. Ferrite and pseudomartensite were present in some of the specimens, but all specimens were quenched at such a rate that pearlite was not formed, in order to ensure the formation of the carbides at temperatures lower than about 500°C. It had been found previously' that in chromium steels the chromium carbide could be produced by transformation of austenite in the pearlite range above 500°C., and, in order to start the tempering treatment with the carbide present as cementite, the absence of pearlite was considered to be essential. The specimens were tempered for 64 hr. to permit the formation of the stable carbide. After tempering, the specimens were submitted to microscopic and X-ray examination. The carbides were separated either electrolytically in a 5 per cent HCl electrolyte or with an acidified copper-potassium chloride solution. The crystal structure of the carbide phases was determined by the Debye-Scherrer type of X-ray patterns. The X-ray patterns obtained from specimens near the boundaries between two types of carbides were generally weak and diffuse as compared with the other patterns. For this reason, and because the more soluble components may be masked, the boundaries between the phases could not be determined precisely. However, the X-ray analysis of electrolytically separated carbides has given consistently reproducible results

Jan 1, 1943

By Charles H. Thurman

THE data given herein were first included in a paper read before San Francisco Section, A.I.M.E., in October 1940, and are applicable to conditions existing until the gold-dredging industry was temporarily suspended by Order L-208 of the War Production Board in the fall of 1942. There is no doubt that gold dredging will be resumed at some future time, and on a scale equivalent to that of the recent past, but the cost data given herein will be affected to some extent by conditions existing at that time, and by labor rates and prices for materials then prevailing. DRAGLINE VS. BUCKET-LINE Dragline dredges should not be considered for mining large areas of low-grade placer gravel. In such deposits a dragline operator with a 5-cu. yd. dragline would be doing well to maintain an operating cost of 6¢ per cu. yd., while a bucket-line dredge with buckets no smaller than 7 cu. ft. each could be operated for less than 4¢ per cu. yd. By operating costs, I mean only field charges such as direct operating and overhead, which includes pay roll, power or fuel, repairs and maintenance, insurance, land clearing and general expenses, but not including such items as prospecting, depletion, depreciation of equipment, State Franchise Tax, or Federal Income Tax. It is not to be inferred that a dragline dredge cannot make a profit in small low-grade deposits, where the extent of a given property is too small to justify the use of the more costly bucket-line dredge. Consider small deposits of 10¢ gravel. It is obvious that a deposit of 5,000,000 cu. yd. of such gravel could not be mined profitably with a new, 7-cu. ft. bucket-line dredge, costing upward of $250,000, and with operation costs at 4¢ per cu. yd., paying for land or royalties out of earnings; nor could a new combination 5-cu. yd. dragline and washing plant, worth upward of $125,000 and working at 6¢ per cu. yd., make a profit. These comparisons are made because the hourly capacity of both types of dredges is nearly the same. The bucket-line dredge averages 93 per cent operating time in 24 hr., as against about 80 per cent or less for the dragline dredge. These percentages of operating time are important factors in making a comparison of this kind. The bucket-line dredge has greater efficiency in cleaning soft bedrock, usually characteristic of dredging deposits, and a 7-cu. ft. bucket-line dredge can be efficient to a total digging depth of 80 ft. (65 ft. below water, 15 ft. above). A 5-cu. yd. dragline dredge is limited to about 30 ft. of efficient digging depth, 5 ft. of which could be above water. In small areas of gravel not over 30 ft. deep, a 5-cu. yd. dragline dredge could make a profit where a bucket-line dredge could not do so. As an example: compare the dredging of 3,000,000 cu. yd. of 10¢ gravel 28 ft. deep with bucket line, costing 4¢ per cu. yd., and with a 5-cu. yd. dragline dredge operating at 6¢ per cu. yd. Because of small yardage, new equipment is not warranted, therefore we can assume that the dredges of both types are used equipment, fully depreciated. Dismantling, mov-

Jan 1, 1945

By H. U. Schutt, J. M. Toguri

REGARDLESS of the degree of purification effected during the electrorefining of copper, a danger of re-introducing impurities exists in the operation of melting and casting of the refined copper. Logically only a combination of the purification and casting operation would remedy the situation. A well-known method of metal purification is the "Gross"-type process, whereby a volatile halide is produced, purified, and decomposed.' In the present case, this concept was used to remove the impurities rather than to form possible volatile copper halides. The object was to produce volatile halides of the impurities present and distill these away, leaving high-purity copper. It is interesting to note that such techniques are used in spectrographic procedures in order to shorten exposure time and enhance the density of impurity lines.' In the present investigation, copper hydroxy fluoride was used, since the temperature of decomposition of copper hydroxy fluoride and the melting point of copper nearly coincide. The fluorine released by the thermal decomposition of copper hydroxy fluoride purges the molten copper. Copper hydroxy fluoride was prepared by dissolving high-purity copper in nitric acid and adding hydrofluoric acid and ammonium hydroxide in the required proportions. The melt was made in a high-purity graphite crucible heated by an induction furnace. Trial experiments showed that impurities can be introduced from the crucible material. Therefore, preceding each cast, the crucible itself was cleaned by decomposing copper hydroxy fluoride and discarding the residual copper. Best experimental conditions were obtained by adding 30 g of copper hydroxy fluoride to 500 g of nor-

Jan 1, 1967

• One effect of the British devaluation of the Pound Sterling, with its resultant lowering of the pay limit, was the addition of considerable tonnages of previously marginal ore in gold mining. Crown Mines, Ltd., reported that 1,245,000 tons of such ore had been added to available reserves. But for devaluation, a steady decline in ore reserves had been a feature of operations during the previous ten years, and would have continued. •Loree Colliery of the Hudson Coal Co. is using a Humphrey spiral cleaning plant to meet requirements of the state in the matter of stream pollution. However, the process is producing a salable product. •Noranda is considering plans for constructing a commercial sized unit designed to produce elemental sulphuric acid and sintered iron oxide from pyrite. Test plant results have indicated the No. 5 ore zone can be treated by the new process economically. •A magnetic fluid clutch, and magnetic amplifiers for motor and generator control, have been developed under Navy contract by Vickers' Electric Division, in St. Louis, Mo. This constitutes the first commercial production of the clutch recently developed by the Bureau of Standards. •Fuel experts estimate coal production will run up to 500 million tons this year based on the expectation that business conditions will continue to be good. They also expect that in the future the use of coal will increase by 50 pct over today's level. These expectations are based on the fact that it provides the bulk of the heat, light, and power for making steel, for manufacturing, and for generating electricity as well as the development of the coal burning gas turbine and processes for making gas, gasoline, and oil from coal. •Entombed miners may benefit from a two-way communication system which utilizes the earth's strata as a network for electric signals. The use of FM radio waves makes this possible. The invention includes a portable transmitter-receiver unit kept near the face, and a more powerful portable equipment of the same sort above ground. In use, two probes on wires from the apparatus are driven into the earth. • The Union of South Africa has launched a uranium production project which government leaders think will help the West maintain world atomic supremacy. Experiments under way in the pilot plants are expected to lead to the establishment of a chain of processing factories along the Witwatersrand in which uranium will be reclaimed from gold tailing. •Recent developments in mechanized mining at the Bureau of Mines oil-shale mine near Rifle, Colo., have lowered mining costs to 29 cents per ton of shale. The cost of producing crude shale oil from 30-gal-per-ton-shale, using the new mining and processing techniques, would be about $1.50 per barrel. This is 500 lower than any previously stated price. • COMINCO is planning to open the old Bluebell lead-zinc mine near Nelson, B. C., on a 500-ton-per-day basis. The old workings will be pumped and a 970-ft incline sunk. A mill will be constructed at the property.

Jan 7, 1950

By Charles H. Thurman

The data given herein were first included in a paper read before San Francisco Section, A.I.M.E., in October 1940, and are applicable to conditions existing until the gold-dredging industry was temporarily suspended by Order L-208 of the War Production Board in the fall of 1942. There is no doubt that gold dredging will be resumed at some future time, and on a scale equivalent to that of the recent past, but the cost data given herein will be affected to some extent by conditions existing at that time, and by labor rates and prices for materials then prevailing. Dragline vs. Bucket-line Dragline dredges should not be considered for mining large areas of low-grade placer gravel. In such deposits a dragline operator with a 5-cu. yd. dragline would be doing well to maintain an operating cost of 6¢ per cu. yd., while a bucket-line dredge with buckets no smaller than 7 cu. ft. each could be operated for less than 4¢ per cu. yd. By operating costs, I mean only field charges such as direct operating and overhead, which includes pay roll, power or fuel, repairs and maintenance, insurance, land clearing and general expenses, but not including such items as prospecting, depletion, depreciation of equipment, State Franchise Tax, or Federal Income Tax. It is not to be inferred that a dragline dredge cannot make a profit in small low-grade deposits, where the extent of a given property is too small to justify the use of the more costly bucket-line dredge. Consider small deposits of 106 gravel. It is obvious that a deposit of 5,000,000 cu. yd. of such gravel could not be mined profitably with a new 7-cu. ft, bucket-line dredge, costing upward of $250,000, and in operation costs at 4¢ per cu. yd., paying for land or royalties out of earnings; nor could a new combination 5-cu. yd. dragline and washing plant, worth upward of $125,000 and working at 6¢ Per cu. yd., make a profit. These comparisons are made because the hourly capacity of both types of dredges is nearly the same. The bucket-line dredge averages 93 per cent operating time in 24 hr., as against about 80 per cent or less for the dragline dredge. These Percentages of operating time are important factors in making a comparison of this kind- The bucket-line dredge has greater efficiency in cleaning soft bedrock, usually characteristic of dredging deposits, and a 7-cu. ft. bucket-line dredge can be efficient to a total digging depth of 80 ft- (65 ft. below water, 15 ft. above). A 5-cu. Yd. dragline dredge is limited to about 30 ft. of efficient digging depth, 5 ft. of which could be above water. In small areas of gravel not over 30 ft. deep, a 5-cu. yd. dragline dredge could make a profit where a bucket-line dredge could not do so. As an example: compare the dredging of 3,000,000 cu. yd. of 10 gravel 28 ft. deep with bucket line, costin 4¢ Per cu. yd., and with a 5-cu. yd. dragline dredge operating at 6¢ Per cu. yd. Because of small yardage, new equipment is not warranted, therefore we can assume that the dredges of both types are used equip-ment, fully depreciated. Dismantling, mov-

Jan 1, 1946

By Frederick C. Langenberg

IT has been shown1 that copper can be removed from iron-base alloys by solvent extraction with molten lead and sodium sulfide slags. In these processes copper removal is favored by a positive deviation of copper in iron from ideal behavior. Chou' determined the distribution of copper between liquid silver and iron and obtained a value for the activity coefficient of copper in iron at 1600°C, y°, of 9.12. Chipman" calculated the activity coefficient from the Fe-Cu phase diagram to be 12 at 1600°C. More recent work by Koros and Chipman" yields a value at 1600°C for y V equal to 8.0. In this latter work, the distribution of copper between silver and iron was measured at 1600°C, while the activity of copper in the silver phase was determined from calculations based on the Ag-Cu phase diagram. The present work presents another value of based on calculations from the Cu-Pb phase diagram, on the heat of mixing data for the Cu-Pb system, and on an experimental study of the distribution of copper between iron and lead at 1600°C. These experiments were part of a larger research on the removal of copper from iron-base alloys conducted at The Pennsylvania State University. Experimental Procedure—The distribution of copper between pure iron and lead at 1600°C was made in the furnace assembly shown in Fig. 1. The melts were made in high purity alumina crucibles under an atmosphere of prepurified argon. Temperatures were read with an optical pyrometer sighted into a %-in. hole drilled in the inductor. Extensive calibration of the optical readings with immersion readings had been carried out previously. The initial charges consisted of 100 g of electrolytic iron and varying weights of copper. The melts were brought rapidly to 1600°C and 75 g of lead added. The temperature was quickly readjusted to 1600°C, and the melts were held for 10 min at this temperature. A sample was then drawn from the iron layer in a fused silica tube. This sample was analyzed to determine the copper content of the iron layer at equilibrium, while the copper content of the lead layer was determined from a material balance. The validity of the material balance was confirmed by a chemical analysis of the entire lead layer for one heat in which the crucible was removed and quenched after the iron sample was taken. The calculated copper content of the lead-rich phase was 1.18 pct; while the entire lead layer analyzed 1.20 pct Cu. The distribution results are shown in Fig. 2. The distribution constant, N,.'r'"/N, is equal to 3.95. Discussion—From the Cu-Pb phase diagram' it can be seen that lead-rich liquid Pb-Cu solutions

Jan 1, 1957

By Oscar Weiss

An aerial magnetometer survey was carried out by the author's geophysical organization over the Vredefort dome, where Witwatersrand beds are wrapped around a granite plug 25 to 30 miles in diameter. The well- known magnetic shales of the Lower Witwatersrand system (to be referred to as LWW) give strong negative anomalies over the out-cropping portion of the dome. This is unusual as these same shales -cause positive anomalies over large areas near Johannesburg and along a strike of 130 miles between the East Rand and Klerksdorp. It is suggested that the negative polarization is caused by heat and stresses connected with the doming. This negative polarization of sedimentary beds, which usually cause positive anomalies, is a good example of how "magnetic lows" can be caused by "structural highs." Significant magnetic anomalies should be tested by gravity and seismic methods irrespective of the sign of the anomalies.

Jan 1, 1949