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By A. Rosenzweig, M. M. Karnowsky

The generalized binary diagram of the Au-Sn-Pb system is presented. The chief characteristic is the pseudobinary between lead and AuSn. On the high-gold side of the pseudobinary, four reaction isotherms were found at 363°, 274°, 225°, and 204°C. On the low-gold side of the pseudobinary, three reaction isotherms at 277°, 205°, and 176°C were found. A vertical section from the eutectic solder composition to gold was developed from the isothermal sections generated. METALLURGICAL problems arising from the intentional or accidental formation of Au-Sn-Pb alloys in soldering applications have indicated a need for information on the phase equilibria in this ternary system. The literature indicates that a complete diagram presenting this information has not been prepared. Even the recent excellent work by prince' entitled "The Au-Pb-Sn Ternary System" actually extends only to the AuSn or 50 at. pct Au range. There are more events in the 50 to 100 at. pct Au than in the less than 50 at. pct range. This article by Prince furnished much guidance in preparing this report. Initial efforts with the isopleth from the eutectic solder composition 61.9 wt pct Sn-38.1 wt pct Pb and 0 to 90 wt pct Au indicated that extensions of the work to the whole of the diagram (even if in less detail) were necessary to understand this system. In undertaking the construction of such a diagram, this study used differential thermal analyses (DTA) and metallography with verification and identification of phases by electron microprobe analyses. EXPERIMENTAL PROCEDURE The procedure began with the development of a cell which would be unreactive with lead, tin, and gold, retain its strength to 1100°C, exclude oxygen, and also furnish a suitable well for insertion and protection of a thermocouple to monitor temperature changes in the material. Such a cell would make it possible to reuse the sample should a repetition of determination be desired. Fig. 1 is a photograph of two such quartz cells as finally developed. The specimens have been run many times. The cell is made up of an inner sample bucket and an outer capsule with a thermocouple well which the sample surrounds. The DTA unit was an assembly devised from available instrumentation. The sample holder was a 3-in.-long cylinder of nickel, 2 1/2 in. in diam, fitted securely in a vertical tube furnace. Two holes 7/8 in. in diam were symmetrically located to receive the quartz cells. A dummy cell with nickel powder was used as the reference. The absolute temperature was recorded with a Pt/Pt 10-pct Rh thermocouple with an automatic Kaye ice bath compensator. (Calibration indicated the compensator to be accurate to better than ±0.5° over the 100° to 1000°C range.) The absolute temperature was measured in the sample and recorded on an L&N mul-tirange recorder with a full-scale display of 1 mv and automatic ranging of 99 mv. The differential signal between the sample temperature and the reference temperature was amplified with an L&N microvolt amplifier and recorded on an L&N Speedomax G recorder. Since two charts were obtained, the chart speeds were equalized and each event was noted on the differential chart, and the temperature at that time was obtained from the temperature record.

Jan 1, 1969

By J. F. Myers, F. M. Lewis

DISCUSSION L. E. Djingheuzian (Canadian Dept. of Mines and Technical Surveys, Ottawa)—In their Summary the authors say: "Reconciling the grinding efficiency with good metallurgy is still a problem." In the discussion of the first paper8 in his reply to W. I. Garms, Mr. Myers states: "Our grinding process with smooth I-in. balls has reduced by nearly one half the metallic losses in the fine micron sizes of the tailing. This is simply because less of the fine micron sizes are produced. Since the + 65 mesh size is the same as formerly, a higher percentage of the intermediate sizes are developed. These sizes have the highest floatability, require the least reagents, and use less floating time. "These factors contribute so heavily to the overall economies that dropping our power grinding gain from 28 pct back to 19 pct is a small detail. However, we feel that this is only a momentary situation and that eventually the best features of the grinding and flotation processes can be brought together, which is as it should be." Italics are mine. The above statements, to me, appear to be the answer to the opening statement in the Summary. Denoting the costs at different power grinding gains as: Power Grinding Power Grinding Gain, 28 Pct Gala, 19 Pct Cost of grinding G G1 Cost of flotation F F1 Value of metallic losses T T1 where G1 > G2 F3 < F, and T1 < T, we have: G1+Fl+T1<G +F+T. Since the authors accept the idea that "grinding in flotation plants becomes part of the &apos;conditioning&apos; of the feed to flotation",4 i.e., that in flotation the ball mill is primarily a conditioning machine, it can be postulated that Tennessee Copper grinding at cost G1 is more efficient than grinding at lower cost G. This can be directly inferred from the Conclusion of the paper. Mr. Myers also emphasizes this at the end of his reply to Mr. Garms: "that grinding is for the purpose of preparing flotation feed and not grinding per se." This, to me, in the final analysis means that when the efficiency of grinding is weighted against the conditioning factor, the former becomes a function of efficient conditioning, hence, within the system in which proper conditioning is the dominant factor, the best grinding efficiency is provided by grinding which will contribute towards the optimum conditioning. This brings us again to the statement: "that if every grinding unit were considered as a conditioner for each following step, efficient grinding plants would become much easier to design."&apos; In other words, grinding equipment should be balanced against the flotation equipment and against chemical reactions taking place in the system. F. C. Bond (Allis-Chalmers Mfg. Co., Milwaukee)— The authors&apos; discussion of the probable ball motion in a slow speed high dilution mill is very interesting. When the 1-in. balls have worn down to about one fourth of their original weight they apparently first develop a flat surface; as wear progresses this flat face becomes concave, and other concave faces appear. It seems more probable that the first flat face may form at the softest part of the ball surface, and that each succeeding contact tends to force this flat face into sliding contact with a larger round ball; than that the flat faced ball tends to pair off with a particular round ball and to travel with it continuously. When the small worn ball has a flat face and is in sliding contact with a large round ball, the surrounding large balls will assume a more or less definite pattern, and slide against the worn ball, thus producing secondary concave faces. The primary concave face seems to be larger and better developed than the secondary faces. The ball charge can be divided into "concaves" which show at least one concave surface, "intermediates" which have developed flats or incipient concaves, and "rounds." Ball slippage is always present in a tumbling mill, and the mutual ball movement is necessarily a combination of rolling and sliding. The sliding motion is apparently concentrated upon the smaller worn balls which nest between the surrounding larger round balls. When each worn ball starts its upward path in the mill its primary flat or concave surface fits against a larger round ball, and the round ball slides upon it. The action may be something like that of the ball separator in a ball bearing, except that the worn sliding balls are always under considerable pressure. The material is ground under the combined influence of breakage 1—by impacts between falling balls and between falling and supported balls, 2—by being nipped between rolling balls, and 3—by being rubbed between the sliding balls. The rubbing action will be increased in the presence of worn balls with concave surfaces. The rubbing action probably produces a considerable portion of the finely ground slimes in the product. The worn balls commonly approach tetrahedrons in shape, and are very different from concavex, each of which has two equal opposed concave surfaces. Concavex were designed only to grind upon themselves, and not for use in combination with grinding balls. Their action in a grinding charge is very different from

Jan 1, 1952

By AIME AIME

ON April 7 the twentieth national Open-hearth Conference of the A.I.M.E. will be held in Birming¬ham, Ala., in conjunction with a meeting of the Committee on Blast Furnaces and Raw Materials. At least 300 engineers and operators are expected to attend. Birmingham, the industrial city and iron, and steel center of the South, has been called the "Magic City." Men actively engaged in business in Birmingham today have seen practically every building in the business district erected, have witnessed the establishment of every existing industry, and have hunted birds cm the site now one of the busiest corners of the business district. Incorporated as a town in 1871, the city today has a population of more than 380,000 in its metropolitan area. It is

Jan 1, 1937

By U. Max, P. R. Geoffroy, J. A. Lawrence

When shaft sinking was begun on the Vendome Mines property in the Barraute area of north-western Quebec, there was no indication of the flat mud seam that was later encountered, and no special precautions were taken in applying conventional methods of grouting. Failure of the first cementing attempt emphasized the important fact that mud is an adverse condition in grouting. A method was then devised that would remove the clay from those portions of the seam adjacent to the shaft, replacing it by a bulky mixture of cement and sawdust. Tests were carried out to insure that the seam had been properly sealed and that excavation could be resumed without endangering the shaft.

Nov 1, 1955

By Leo Horvitz

PETROLEUM and natural gas are composed principally of the saturated hydrocarbons ranging from methane, the lightest, to nonvolatile liquids and solids containing approximately thirty-five carbon atoms. A technique for locating buried accumulations of these hydrocarbons before drilling obviously requires that some of the hydrocarbons leave the deposit and migrate toward the surface of the earth where they may be detected in their original form. Earliest attempts to link near surface hydrocarbons to petroleum at depth were apparently made by Laubmeyer1 in Germany and by Sokolov2 in Russia. These investigators collected samples of soil air from boreholes one to two meters deep and analyzed them for traces of hydrocarbons. They found that soil air over producing areas is richer in these constituents than is soil air over barren areas.

Jan 12, 1954

By E. W. Dewing

The solubility of A14C3 in cryolite melts has been determined by holding the melt with aluminum in a graphite crucible for 4 hr at temperature, quenching the crucible in water, and analyzing the frozen salt by CH4 evolution. The solubility is given by log(wt % Al4C3) = 1.298 -1.l74 (wt ratio NaF/AlF3) independent of temperature in the range 985" to 1080°C. Additions ofA1203, .NaCl, CaF2, or LiF up to 10 wt pct do not affect the solubility, provided that LiF and CaF2 are replaced by equivalent NaFin calculating the ratio. The variation with ratio can be accounted for quantitatively on the hypothesis that the Mechanism of solution is Al4C3 + 2AIF3 = 3Al2CF2 since the solubility varies as (aAIF3) 2/3; Mechanisms involving C", C2- , AlC- , A12C2+, and Al2CF+are re-jected. At ratios above 1.5 truces of c;- are also present. It was noticed some years ago in this laboratory that carbon specimens made cathodic in a cryolite bath decrease in diameter over a period of time.&apos; It was also found that cryolite which had been melted with aluminum in a graphite crucible was sometimes yellow, and that A14C3 could be seen intimately embedded in the cryolite crystals. CH, could be recovered by acid attack. There was thus reason to believe that A14C3 had a genuine solubility in molten cryolite, and the object of this work was to measure it. EXPERIMENTAL AND RESULTS A graphite crucible, 2 in. ID and 2.5 in. deep with a close-fitting lid, contained about 150 g of cryolite (plus additives) and about 20 g of 99.99 pct pure Al. It was placed in a vertical Inconel furnace tube, covered with refractory brick to provide thermal insulation, and the top of the tube was roughly sealed with disks of asbestos paper. An alumina tube led argon down to the level of the top of the crucible to expel air, and an alumina sheath with a Pt-10 pct Rh ther-mocouple inside was positioned between the crucible and the wall of the Inconel tube. The tube was heated in an electrical resistance furnace for the desired length of time; the refractory bricks were then removed, and the crucible was lifted out with tongs and quenched in water. After such a crucible was broken open it could be seen that its inner surface was yellow owing to the presence of A1,C3, and sometimes needle-like crystals could be observed (at X75 magnification) growing out into the nielt. It was concluded that Al,C, had been present as a separate phase when the crucible was at tenlperature and that the melt had been saturated: in

Jan 1, 1970

By Wm. R. Webster

This is a contribution for the proposed new discussion on the physics of steel. The former discussion on the subject started with the consideration of five papers presented at the Chicago meeting in 1893, and continued for several years. The Suggested Lines of Discussion, prepared by Doctor Howe, covered a wide field and added greatly to the success of the work. Naturally, the first step in a new discussion will be to remodel and bring up to date the old Suggested Lines of Discussion so as to embody all the important advances in the metallurgy of steel that have a bearing on the physics of steel and keep the papers and discussions within the field of work undertaken. This paper will be devoted to the practical application, in rolling steel, of the effects of carbon, phosphorus, and manganese on its tensile strength, with some suggestions on further research work. Dr. J. E. Stead, in his paper Influence of Some Elements on the Mechanical Properties of Steel,&apos; gave a complete review of all that had been done during the past thirty years. He gave full credit to all investigators who worked on these lines, also their results, with his views on same, and in many cases his own results. All of this data and much new valuable information were put in convenient shape for reference and study. To do this required a great deal of work, which is fully appreciated by the steel manufacturers and investigators. The variations in the values given by the different investigators for the increase of the tensile strength of steel for each 0.01 per cent. of carbon, phosphorus, and manganese were largely due to the steels they worked on, the large or small variations in the amount of the elcments present, and the omission to take into consideration all the factors, from the blast furnace through to finished rolled material, that affect the character of the steel. For instance, a poorly made dirty steel requires considerably more carbon to give the same ultimate strength than a well-made clean steel with the same phosphorus and manganese content.

Jan 1, 1922

By Wm. R. Webster

This is a contribution for the proposed new discussion on the physics of steel. The former discussion on the subject started with the consideration of five papers presented at the Chicago meeting in 1893, and continued for several years. The Suggested Lines of Discussion, prepared by Doctor Howe, covered a wide field and added greatly to the success of the work. Naturally, the first step in a new discussion will be to remodel and bring up to date the old Suggested Lines of Discussion so as to embody all the important advances in the metallurgy of steel that have a bearing on the physics of steel and keep the papers and discussions within the field of work undertaken. This paper will be devoted to the practical application, in rolling steel, of the effects of carbon, phosphorus, and manganese on its tensile strength, with some suggestions on further research work. Dr. J. E. Stead, in his paper Influence of Some Elements on the Mechanical Properties of Steel,&apos; gave a complete review of all that had been done during the past thirty years. He gave full credit to all investigators who worked on these lines, also their results, with his views on same, and in many cases his own results. All of this data and much new valuable information were put in convenient shape for reference and study. To do this required a great deal of work, which is fully appreciated by the steel manufacturers and investigators. The variations in the values given by the different investigators for the increase of the tensile strength of steel for each 0.01 per cent. of carbon, phosphorus, and manganese were largely due to the steels they worked on, the large or small variations in the amount of the elcments present, and the omission to take into consideration all the factors, from the blast furnace through to finished rolled material, that affect the character of the steel. For instance, a poorly made dirty steel requires considerably more carbon to give the same ultimate strength than a well-made clean steel with the same phosphorus and manganese content.

Jan 1, 1922

By L. G. Evans, W. W. Simpson, W. A. McKinney

In conventional dump leaching of strip wastes from open-pit porphyry mining operations, many years are required to extract a fraction of the copper from the contained sulfide minerals. Furthermore, none of the molybdenum, gold, or silver is recovered by current leaching practices. Because the copper sulfide minerals and molybdenite generally are distributed in the minute fractures throughout the host rock, the mineral values tend to concentrate in the finer fraction of the strip material. This suggests the possibility of segregating the enriched fines in as-produced or coarsely crushed strip wastes for blending with the ore grade flotation mill feed. In the past, extra handling or crushing of mine wastes to enable better leach extraction has been deemed uneconomical. However, recent articles on mobile crushing plants and conveyor haulage systems indicate possible cost improvements for these techniques over conventional truck haulage of ore and mine wastes. Another potential benefit from removal of the fines from copper-bearing mine waste derives from the increased permeability of the coarse dump material to leach solutions and air. Better permeability should result in faster oxidation of the sulfide minerals, less channeling of leach solutions, and fewer perched solution tables caused by compacted fines. Therefore, in addition to the metal values recovered by flotation, higher copper recoveries by leaching also might be achieved. The Salt Lake City Metallurgy Research Center of the U.S. Bureau of Mines undertook an investigation to determine the feasibility of removing enriched fines from strip waste material for separate treatment by froth flotation for early recovery of part of the copper, molybdenum, gold, and silver. Percolation leaching tests were made on mine-run and sized fractions of the dump material to determine the effect of fines removal on copper extraction. Samples Tested Three 10-ton samples of copper sulfide-bearing mine waste were obtained for the investigation. Partial chemical analyses of the samples are given in [Table 1] and the consolidated results of detailed screen analyses made on the samples are given in [Table 2]. The -1/4-in, fine fractions contain from 16 to 32% of the copper and 19 to 40% of the molybdenum in 11 to 18% of the total waste. The samples also were crushed to -3 in. to determine the feasibility of crushing to obtain a higher distribution of the metal values in an enriched fine fraction while providing a more leachable coarse fraction that could be transported by a conveyor system to a dump. The -%-in. fine fractions screened from the crushed mine waste were almost identical in grade to the natural fines. From 2 to 4% more1/4-in. fines were produced by crushing to -3 in. Copper distribution was increased by about 3% over that in the natural fines, while molybdenum distribution was increased by about 10%. The -1/4-in. fines screened from the mine-run and crushed strip waste were almost as high in grade as the ore being treated at the mills. In addition, the fines

Jan 1, 1974

By Colin C. Harris, Nathaniel Arbiter

The flotation operation can be analyzed in terms of three groups of variables. The first, largely independent of control by the operator, embraces the fixed physical and chemical properties of the ore minerals. The second includes all chemical and physical effects imposed on an ore after mining that influence its floatability. These can be either purposefully or accidentally applied. The third embodies the flotation-machine characteristics which realize the potential floatability of selected ore minerals in terms of grade and recovery levels. The machine effectiveness thus depends not only on its own contribution, but on the prior influence of all other variables on floatability. HISTORICAL DEVELOPMENT From the earliest days, flotation mills used many types of machines. Hoover 20 in 1914 mentioned as then important the Potter-Delprat tank for gas generation by acid, the DeBavay cones for skin flotation, the Elmore mixer and separation chamber for vacuum flotation, and his own modification of the Mineral Separation cell for the agitation froth process. Less important at the time were the MacQuisten tube and the Hyde cell. By 19274~ scores of machines had been developed and dozens had found their way into mills. From then on, however, under the scrutiny of competitive tests, many fell into disuse. Taggart in 19454~ classified processes broadly as skin flotation and froth flotation, dividing machines for the latter into the three categories: bubble column, pulp body, and combination.* Under &apos;bubble column&apos; he listed all pneumatic, cascade, and subaeration cells; and under &apos;pulp body&apos; those cells in which gas was generated by boiling, chemical action, and pressure reduction, as well as the agitation-froth type. At that writing skin flotation, the cascade machines, and all pulp body and combination machines were said to be extinct, leaving pneumatic and subaeration types dominant (u. S. practice). The process of elimination has continued to the present, with almost all pneumatic cells succumbing to the pressure of competition from subaeration machines. The only new machines to appear in recent years have been double-impeller types f and these have met with only limited acceptance.

Jan 1, 1962

IN discussing the art of the goldsmith, it is apparent that it is an art requiring skill. He who wishes to be acclaimed a good master therein must be a good universal master in several arts, for the different kinds of work that come to his hands to be done are infinite. Those who work in gold and silver must outdistance all other craftsmen in learning and achievement to the same degree that their materials outdistance other metals in nobility. Therefore, it is necessary first of all to be a good designer, because design is the key that opens the doors not only to the goldsmith&apos;s craft but to all others. Then it is necessary that he understand melting and that he know well how to work with a hammer and how to use flat gravers and burins in engraving, as well as files and chisels. He must also possess certain secrets that are needful to the art, which in truth are parts of alchemy, such as softening gold when it is brittle and raw, coloring it when it has little color, soldering, enameling, working in niello, blanching, gilding, and an infinite number of things which must all be known in detail. But above all he who wishes to do this art well must be very patient in working, must know how to mould and how to proceed with the melt and with the file, hammer, chisel, or other implements for bringing his gold or silver work to the final state which he plans. He must also have good judgment in gems and know well how to recognize every [134v] good or defective quality they possess, and to distinguish the false gem from the true, either when set or when unmounted, as there is need; also how to value them both in buying or selling and in satisfying others who seek his appraisal. He should also be experienced not only in the technique of melting but also in the methods of assaying, parting, refining, cementing, and the like, and still many others. But if I wished to tell you of every part

Jan 1, 1942

By Stanley C. Herold

Only two years ago there appeared in our technical magazines articles wherein it was shown that the application of back-pressure increased the ultimate production of a well, that edge water can be stopped in its encroachment by the injection of gas into the productive formation, with the consequent conservation of energy within the pool, that gas is the source of all energy involved in oil production, and that each pool has a definite minimum-valued gas-oil ratio to be attained for the most economical operation of wells. Today we are not so certain of these matters. Probably in some fields, under special circumstances, these ideas are correct, but certainly they must not be correct in all fields, under any and all circumstances. The nature of the productive structure, the location of particular properties on the structure, the existence of adjoining neighbors, whether these are higher or lower on the structure, and the methods of production followed by all operators on the structure, sand for sand on depth, make these subjects worthy of full consideration. Our difficulties in analyzing and comparing the performance of reservoirs in various parts of the world do not rest solely upon structural features and property lines. We do not complete the list of causes for these difficulties if we add lithologic features and correlation of strata encountered by the drill, with the magnitude of pressures exerted by fluids within any of these strata. A further cause, one which the author believes will complete the list, is one involving the theoretical mechanics of fluids within porous formations—porous in the nature of interstices in sandstones and some limestones, networks of fractures in shales, and cavities in otherwise compact limestones. The confusion of ideas concerning reservoir mechanics still with us today seems largely due to our failure to recognize among all wells three great divisions of theoretical mechanics, three great systems which are distinct in themselves, and according to which each well, or better, each group of wells, must be analyzed separately. These systems have been named by the writer Hydraulic Control, Volumetric Control and Capillary Control, respectively.&apos; Wells in these controls behave dif-

Jan 1, 1930

By Wm. R. Webster

THIS is a contribution for the proposed new discussion on the physics of steel. The former discussion on the subject started with the consideration of five papers presented at the Chicago meeting in 1893, and continued for several years. The Suggested Lines of Discussion, prepared by Doctor Howe, covered a wide field and added greatly to the success of the work. Naturally, the first step in a new discussion will be to remodel and bring up to date the old Suggested Lines of Discussion so as to embody all the important advances in the metallurgy of steel that have a bearing on the physics of steel and keep the papers and discussions within the field of work undertaken. This paper will be devoted to the practical application, in rolling steel, of the effects of carbon, phosphorus, and manganese on its tensile strength, with some suggestions on further research work. Dr. J. E. Stead, in his paper Influence of Some Elements on the Mechanical Properties of Steel,1 gave a complete review of all that had been done during the past thirty years. He gave full credit to all investigators who worked on these lines, also their results, with his views on same, and in many cases his own results. All of this data and much new valuable information were put in convenient shape for reference and study. To do this required a great deal of work, which is fully appreciated by the steel manufacturers and investigators. The variations in the values given by the different investigators for the increase of the tensile strength of steel for each 0.01 per cent. of carbon, phosphorus, and manganese were largely due to the steels they worked on, the large or small variations in the amount of the elements present, and the omission to take into consideration all the factors, from the blast furnace through to finished rolled material, that affect the character of the steel. For instance, a poorly made dirty steel requires considerably more carbon to give the same ultimate strength than a well-made clean steel with the same phosphorus and manganese content.

Jan 3, 1921

By Morris Muskat, James M. McDowell

A report is given of electrical analog experiments on the effect of casing perforation completions on well productivity for ideal uniform reservoirs under steady state homogeneous fluid flow conditions. Graphical results are presented for the effect of perforations of different densities and various degrees of penetration into the formation surrounding the casing or cement sheath. The latter range from perforations which terminate flush with the casing to those which extend into the formation a distance equal to the casing diameter. For the special case where the perforations terminate immediately beyond the casing with semi-spherical protrusions the electrical analog results correct and supersede previously reported theoretical calculations. It is found that the penetration of the perforations into the surrounding productive section may so increase the resultant productivity as to approach or even exceed that for open hole completions. INTRODUCTION A theoretical analysis of the effect of casing perforation on well completion, without additional penetration of the formation, was reported several years ago.&apos; In this treatment the perforations were represented by mathematical sinks and no explicit account was taken of the imperviousness to flow of the casing in which the perforations were made. This procedure was justified by consideration of the mutual interference between the sinks, which seemed to indicate that the analytical method automatically eliminated flow across the casing radius between the perforations. However, both further theoretical investigation and the electrical analog measurements described below showed that this assumption in the previously developed theory was not valid and that the calculated well capacities would considerably exceed the correct values. § Even if this simplifying assumption were retained the generalization of the theory to situations where the perforations extend into the producing formation would be extremely difficult. On the other hand, the electrolytic model analog of this type of steady-state homogenous fluid system is, in principle, so simple that it has not been worthwhile to attempt to develop the exact analysis even for the more limited case of strict casing perforation. The whole problem has therefore been studied anew by electrical models to cover the range from holes in the casing which terminate flush with the casing surface to such as extend into the surrounding rock to a depth equal to the casing diameter. It is to be expected that the productivity of a well completed with casing radius* rw, perforated with holes of radius Tp, and extending to depths d into the surrounding rock, would depend primarily on the dimensionless geometrical parameters Te Tw TP d of the system, such as —, —, — , and —, where re is the Tw, a a rw external boundary radius and a is the mean vertical separation between the perforations. It will also depend, of course, on the number of perforation lines or total perforation density. While such parameters automatically control analytical treatments, it would require a very extensive series of model experiments to fully disclose their functional effect on the well productivity. For practical purposes, however, a rather limited range of the variables suffices to give the effects of interest. Accordingly, in the experimental study reported here the casing diameter has been kept fixed? at six in., the perforation diameter has been taken as either one-fourth in. or one-half in., their density has been varied from one to eight per ft, and their penetration into the formation has ranged from zero to six in., with a primary scaling factor of one to six. EXPERIMENTAL METHOD AND RESEARCH Although electrolytic model experiments have been made for years, there still seems to be some question as to what set of conditions will give the best results. For this reason a number of electrode materials and electrolytes were tried. Those chosen for the final experiments were copper electrodes and a weak copper sulphate solution as the electrolyte. This &apos;Assuming that the casing has been cemented with a uniform and impermeable cement sheath, the effective casing radius is to be interpreted as the external radius of the cement annulus. It is also assumed here that the casing is set through the complete producing section that it is perforated throughout with a uniform density and that tie formation has a a and isotropic permeability. As noted later, however, a uniform scale change permits reinterpreting the primary measurements to correspond to a casing diameter of 12 in.

Jan 1, 1950

By Emma Smith, R. W. Guard

INVESTIGATION of the nickel-rich end of the Ni-Zr system has been prompted by an interest in the effect of small amounts of zirconium in high temperature alloys. Hansenl presents a hypothetical diagram based on the work of Allibone and Sykes,2 who investigated the system up to 44 atomic pct (55 wt pct) Zr by metallographic means. Since the alloys they used were melted in Alundum crucibles they were probably contaminated with appreciable amounts of aluminum. They found two compounds which they called Ni3Zr and Ni4Zr. Hayes, Roberson, and Paasche3 identified a compound NiZr (50 atomic pct Zr) with a melting point of 1470°C. Such a high melting compound is not compatible with the observation of Allibone and Sykes2 hat a eutectic is formed near 50 atomic pct. The alloys containing up to 60 atomic pct Zr were melted in an inert atmosphere in a noncon-sumable electrode arc furnace. Analysis of most of the alloys indicated negligible loss of zirconium. The alloys were examined in the as-cast condition and also after annealing for 6 hr at 1175°C (or 1000°C for the alloys between 25 atomic pct and 45 atomic pct). Metallographic specimens were etched using mixtures of HF-HNO3-H2O or acetic acid- HN0,-H,O. The specimens for the solidus determinations were wrapped in molybdenum foil and sealed in evacuated quartz tubes. Specimens to be heated above 1300°C were enclosed in zirconia tubes inside the quartz to prevent reaction with molybdenum. The solidus determinations were carried out by heating the specimens at various temperatures for a few minutes and then examining the interior structure metallographically to determine at what temperature melting began. The 150 mesh powders for X-ray analysis were annealed in an evacuated quartz tube for 2 hr at 540 °C to remove cold work. Alloys with 22.5 atomic pct Zr and 44.4 atomic pct Zr required annealing at 700 °C for complete recovery. The grains of both of these alloys were soft and rather ductile. Both Debye-Scherrer film patterns and spectrometer traces were made for each alloy using filtered copper radiation. Results and Discussion The presence of a substantial amount of second phase in an alloy with 1.1 atomic pct Zr indicated that the solid solubility of zirconium in nickel is somewhat less than 1 atomic pct. The a0 value for the face-centered-cubic matrix in the same alloy was equal to that of pure nickel, so that the solubility must be very small. This observation is as expected from the large atom size difference. Annealed specimens of alloys with 15.0, 16.7, 22.5, 28.6, 44.4, and 59.4 atomic pct Zr showed. micro-structures that were essentially single phase. When

Jan 1, 1958

By L. C. Morganroth

From a geological standpoint, but scant attention has been paid to fire-clay beds. Only within the last few years have they been the subject of individual investigation, prior to this time having been considered only in their relation to coal seams. While the relative importance of coal and fire clay is still immeasurably in favor of coal, yet an industry as large as that of fire clay is entitled to a measure of attention. A discussion of the Carboniferous clays is practically a discussion of the clay beds in the Appalachian basin, since more than 90 per cent. of these clays mined are from this region. The clays are confined to the northern end of the basin, or the States of Pennsylvania, Ohio, Kentucky, Maryland and West Virginia, ranking in importance about in the order named. The clay deposits of the Carboniferous period have been divided into two classes; those found in the Pottsville conglomerate series of rocks, &apos; and all those that are found in the formations above, for the reason that the clay beds above the Pottsville series all resemble each other in properties, composition and appearance, and all are distinctly different from the bed found in the Pottsville formation. The bed of clay found in the latter formation is unique in that flint clay is practically restricted to it. (A variety of flint clay is occasionally found in these upper deposits but this is in such small amounts as to be negligible.) Carboniferous clays occur between stratified rocks; sandstones, limestones, etc., in the same manner as coal veins. They are often accompanied by a coal vein although where the clay is of a workable thickness, the coal is generally too thin to work. The clay beds are sometimes known by the name of the coal seam at which horizon they occur. Clay beds may be from a few inches up to 20 ft. in thickness. They may consist of all soft clay, all flint or both soft and flint. The Carboniferous clay beds of Pennsylvania are the most important of any of the clay beds found in the country, and are among the oldest ones worked. We know more about this clay geologically for the reason

Jan 1, 1916

By Leon W. Dupuy

INTRODUCTION A BRIEF elemental discussion of the fundamental factors involved in diamond drilling often fills a need, particularly when a mine operator is contemplating for the first time an exploratory drilling campaign. Mr. James A. Barr, of the Mining Methods Committee of the Institute, has suggested that many engineers must undertake a drilling program of one kind or another and, in the case of diamond drilling, sometimes even are at a loss as to how to start correspondence. The Bureau of Mines has acquired much experience in managing exploratory diamond-drilling activities. Its activities in diamond drilling included exploring for potash in Texas, Utah and New Mexico 1-4 during the 1920&apos;s. The Strategic Minerals Exploration program was started in 1939 and was materially expanded during the war to include critical and essential minerals. At the peak of its war-time activity more than 200 engineers were employed, a majority of whom supervised diamond drilling. Many of them had little experience with such work prior to their employment with the Bureau, and it was necessary to instruct them in their duties. The purpose of this paper, therefore, is to present the fundamentals of exploratory diamond drilling from the viewpoint of management in such a way that they will serve as a basis on which those beginning exploratory diamond drilling may build an experience and acquire ability to direct exploration as they gain that experience. SELECTION OF METHOD OF DRILLING Selection of the method of drilling is governed by the type of material to be penetrated and by the type of sample needed to determine the quality and importance of a deposit. Types of drills that might be used for a given job include diamond drills, churn drills, hand auger drills, power auger drills, bucket drills, and rotary drills (sometimes called "seismograph rigs"). Each type has a specific field in which it is most useful. While the Bureau of Mines utilized all the types of drilling mentioned, diamond drilling was used on a majority of its exploratory projects. FACTORS GOVERNING SELECTION OF DIAMOND DRILLING The prime consideration in selecting a method of drilling is first to determine what results are desired and then to choose a method that will furnish reliable data in the ground to be penetrated. Use of diamond drills permits recovery of a core as well as sludge at a comparatively low cost. The core provides an excellent means of studying the formation being drilled and furnishes much information that would be difficult to obtain otherwise. Diamond drills will recover a satis-

Jan 1, 1947

By Bruce W. Gonser, Robert I. Jaffee

Recent work by the authors1 established the constitutional diagram of the gold-germanium system. Of particular interest in the simple euctectiferous system was the eutectic alloy at 12 per cent Ge, which melted at the very low temperature of 356°C and had an unusually fine eutectic structure. It was of interest to investigate the effect of third components on the melting point, microstructure, and strength of this alloy, and in this work the effect of copper is discussed rather completely, with less complete data on the effects of silver, platinum, nickel, and zinc. No reference in the literature has been found on ternary systems with gold-germanium. Materials and Alloying -4s in the work on the binary system, gold-germanium, the germanium used in this investigation was the cyanide-reduced, 99.9 per cent product, produced by the Eagle-Picher Co. Fine gold sheet from Handy and Harmon, pure platinum sheet from the American Platinum Works, copper magnet wire from Anaconda, nickel wire assaying 99.6 per cent Ni. and electrolytic zinc were used for alloying. To make the alloys, charges of the pure metals were put in a graphite crucible and melted in an atmosphere of pure hydrogen. The temperature was brought up to about I050 C, and the metal allowed to freeze in the crucible. Except with alloys containing zinc, melting losses were consistently less than a few milligrams. When zinc was a component, weight losses up to half the weight of the zinc present were incurred, and the alloy compositions were calculated by assuming the entire weight loss to be that of zinc. In all other cases the composition of the alloys could safely be taken as that of the charge. The ingots, as solidified, were segregated, the heavier primary phases being at the bottom and sides of the ingots and the lighter primary phases at the top, but by sectioning the entire ingot vertically for microscopic examination, this factor could be evaluated. Ingots for microscopic examination weighed one gram, and those for thermal analysis weighed three grams. Thermal Analysis In this work, the eutectic line composition and thermal arrests were desired, and, after microscopic exploration had established the position of the eutectic line at a given percentage of the third component, a thermal analysis was run at that composition. The method of thermal analysis used in the work on the binary Au-Ge system,&apos; a method particularly well suited for a small quantity of material, was used in this work. Clearly defined arrests were obtained, although with some alloys containing platinum

Jan 1, 1946

By Robert I. Jaffee, Bruce W. Gonser

Recent work by the authors1 established the constitutional diagram of the gold-germanium system. Of particular interest in the simple euctectiferous system was the eutectic alloy at 12 per cent Ge, which melted at the very low temperature of 356°C and had an unusually fine eutectic structure. It was of interest to investigate the effect of third components on the melting point, microstructure, and strength of this alloy, and in this work the effect of copper is discussed rather completely, with less complete data on the effects of silver, platinum, nickel, and zinc. No reference in the literature has been found on ternary systems with gold-germanium. Materials and Alloying -4s in the work on the binary system, gold-germanium, the germanium used in this investigation was the cyanide-reduced, 99.9 per cent product, produced by the Eagle-Picher Co. Fine gold sheet from Handy and Harmon, pure platinum sheet from the American Platinum Works, copper magnet wire from Anaconda, nickel wire assaying 99.6 per cent Ni. and electrolytic zinc were used for alloying. To make the alloys, charges of the pure metals were put in a graphite crucible and melted in an atmosphere of pure hydrogen. The temperature was brought up to about I050 C, and the metal allowed to freeze in the crucible. Except with alloys containing zinc, melting losses were consistently less than a few milligrams. When zinc was a component, weight losses up to half the weight of the zinc present were incurred, and the alloy compositions were calculated by assuming the entire weight loss to be that of zinc. In all other cases the composition of the alloys could safely be taken as that of the charge. The ingots, as solidified, were segregated, the heavier primary phases being at the bottom and sides of the ingots and the lighter primary phases at the top, but by sectioning the entire ingot vertically for microscopic examination, this factor could be evaluated. Ingots for microscopic examination weighed one gram, and those for thermal analysis weighed three grams. Thermal Analysis In this work, the eutectic line composition and thermal arrests were desired, and, after microscopic exploration had established the position of the eutectic line at a given percentage of the third component, a thermal analysis was run at that composition. The method of thermal analysis used in the work on the binary Au-Ge system,&apos; a method particularly well suited for a small quantity of material, was used in this work. Clearly defined arrests were obtained, although with some alloys containing platinum

Jan 1, 1946

By C. Ernest Birchenall, Robert F. Mehl

Application of diffusion laws in the customary form to experimental studies in binary metallic solid solutions has shown the diffusion cocfficient to vary with concentration for all systems investigated. The factors determining this variation have not been ascertained. However, the question of whether the diffusion coefficient would become a constant, independent of concentration throughout a single phase if the concentration gradient in the diffusion equation were replaced by an activity gradient has been an attractive subject for speculation. Wagner¹ derived an expression for the force acting on a diffusing particle in terms of the chemical potential. This was also the approach chosen by Jost2 in his monograph. From a somewhat different point of view, Eyring3 and his co-workers have used activity gradients when dealing with diffusion in concentrated nonideal solutions. The only actual test with experimental data is that given by Darken,4 though this is more qualitative than quantitative. Many others opposed the application in any way of thermodynamic concepts to kinetic phenomena, including diffusion processes. A rigorous examination of this principle requires good data expressing the relationship between activity and concentration for solid solutions for which reliable diffusion work has been done. The literature provides such information only for the interstitial solution of carbon in gamma iron (austenite) and for the substitutional copper-zinc solutions (alpha brass). Activity data for carbon in austenite at 800°C and 1000°C are available from the recent work of Smith5 on the equilibrium of hydrogen-methane and carbon monoxide-carbon dioxide mixtures with gamma iron. Combining these with the diffusion studies of Wells and Mehl6 makes possible a quantitative test for this interstitial solid solution. The vapor-pressure determinations for zinc over brass by Hargreaves7 allowed the calculation of activities in this system over a wide range of temperatures and concentrations. Extensive investigation of diffusion in this substitutional solid solution has been carried out by Rhines and Mehl.8 Activities in Brass9 If the vapor phase of zinc is assumed to behave as an ideal gas, any solid or liquid solutions that are in equilibrium with the same partial pressure of zinc at the same temperature have the same thermodynamic activity of zinc. In order to assign a numerical value to the activity azn, it is necessary to choose some standard reference state to which an activity value of unity is arbitrarily assigned. It is customary to choose the liquid or solid state of the pure material. Then azn is defined numerically by

Jan 1, 1947