Search Documents

By George E. Cole

While many parts of Canada's pre-Cambrian shield are well served by railway, it is frequently necessary for prospecting purposes to proceed farther into areas inaccessible by rail. To such areas in summer the canoe was at one time the accepted means of travel for the prospector while the dog team was much used in winter. Although summer travel was much improved by the development of the outboard motor, the lack of facilities for cheap transportation has been a serious hindrance to the employment of capital in opening up the distant fields. The pre-Cambrian surface of Manitoba, like that of Ontario, is hummocky, with rounded hills and ridges of rock alternating with basinlike depressions and valleys occupied by lakes and rivers Or by many low-lying portions covered with muskeg' Routes to the mines have not usually been direct or easy and seasonal vagaries have presented problems in themselves. In summer, water transportation may be the cheapest method for the longer distances but it is not every water route that will satisfy the conditions of loading freight on to a boat or scow and of conveying it without interruption to its destination. By its location, a mine may require a large program of boat transportation in summer Over part of its route, to be followed by winter freighting for the remainder. In order to carry on development and produc- tion over a long period, it may be necessary to haul large quantities of supplies during the winter. This seasonal problem, particularly for the out-of-the-way properties, is SO important and demanding as to make it a major operation in the life of the mine. The -use of the tractor during winter months for heavy machinery and bulk supplies, and the use of the airplane throughout the year for the transportation of personnel and for emergency requirements, have greatly improved transportation to places that are inaccessible by rail. Canada has pioneered in both these methods. Development oF Transportation Twenty-two years have seen a marked change in transportation methods in Canada's mining country. Horse-drawn sleighs have given way to the tractor and that to some extent has been supplanted by the airplane. One of the earliest ventures involving transportation of considerable magnitude was that of the Mandy mine, on Schist at in northern Manitoba. According to accounts of early mining activities in Manitoba, the Mandy mine, beginning December 1916, had 3300 tons of ore hauled 40 miles by sleigh to Saskatchewan River and in summer this was conveyed by barge to The Pas, 130 miles, and then by railroad to Trail, British Columbia, 1200 miles. The mine shipped 6000 tons of ore in 1918 and 15,000 tons in 1919. In winter of the latter year, as many as 300 teams of horses were used on the 40-mile stretch to

Jan 1, 1943

By A. Adiaddevich

Petroleum has been found in Russia in various localities from north to south, as may be seen from the list given below: (a) In the basin of the Petchora river, Northern Russia. (b) In the basin of the Volga river, in the governments of Samara and Saratoff. (c) In the government of Astrakhan and in the Uralsk territory, close to the northern and eastern coast of the Caspian sea. (d) At Grozny in Northeastern Caucasus. (e) In the Daghestan territory, Eastern Caucasus, on the Caspian sea. (f) On the Apsheron peninsula (Baku and other districts) close to the Caspian sea shore. (g) On the island of Tcheleken in the caspiah sea, also on the island of Sviatoi. (h) In the Transcaspian territory on the Neftianaia Gora (Oil hill) and on the surrounding hills. (i) In the Ferghana valley in Russian Central Asia. (j) On the Kertch-and Taman peninsulas on the Black sea. (k) In Siberia it has been discovered in the Transbaikal territory and on the island of Sakhalin.. ' ' In the above-mentioned districts petroleum has been found to exist under different geological conditions and to vary in its chemical and physical properties. At the present time petroleum is produced in Russia at Baku, Grozny, on the island of Tcheleken, in the Ferghana district, and in the Uralsk territory. The yearly production in 1912 throughout the Russian Empire amounted to 69,400,000 barrels, of which the Baku fields were responsible for 52,000,000 barrels. This shows that the Balm fields on the Apsheron peninsula are the chief oil-producing centers in Russia, being at the same time the oldest of all our oil fields. In this paper I shall discuss the Baku fields only, leaving all the others until a later date. The Apsheron peninsula in the Eastern Caucasus protrudes into the Caspian sea in the shape of a triangle some 47 miles long covering a total area of some 750 square miles. The eastern part of the peninsula is a flat, slightly rolling plain, rising in its highest parts to 140 to 170 ft. above

Jan 1, 1915

By P. Somasundaran, R. D. Kulkarni

Reagentizing at elevated temperature, reported in the past as beneficial for the flotation of hematite using oleate, is studied here as a function of collector concentration, solution pH and ionic strength at various levels of conditioning temperature. The study revealed strong interactions between variables; particularly, the effect of conditioning temperature was found to strongly depend on the ionic strength of the solution. Thus, while an increase of conditioning temperature at lower ionic strengths or that of ionic strength at lower temperatures resulted in an increase of both flotation and grade, an increase of the former at higher ionic strength or that of the latter at higher temperatures caused a significant decrease in both responses. These observations have been explained in terms of the increased chemisorption of oleate at elevated temperatures and the temperature effect of ionic-strength on the salting out of the oleate from the bulk solution. The above effects which were first observed during Hallimond cell flotation tests were subsequently tested with Denver cell using low-grade iron ore. The results obtained using the two test procedures were in agreement with each other. The implications of these effects and interactions for process control of optimum flotation performance must be noted since variation in the levels of the above parameters are likely under plant conditions.

Jan 1, 1978

By Raimo Matikainen

Sublevel stoping has been used in Finland since the 1930's and today more than ten under- ground mines have adopted it as their main stoping method (Fig. I). Approximately 80% of the total underground tonnage is mined by sub- level stoping (Table 1) The first mines to introduce the sublevel stoping method in Finland were limestone mines. The development of sublevel stoping was very slow up to the mid 1960's when the switch to trackless mining started and the increase of mechanization lead to higher capacity and productivity. The method itself has been almost the same since the 1950's when long hole drilling was introduced. According to a future prognosis sublevel caving will give way to sub- level stoping; on the other hand, open pit mining will at the same time grow rapidly with some new mineral orebodies, which will he brought into production. Most Finnish orebodies are, however, only marginal ores and they could not support mining with more expensive methods than open pit mining or sublevel stoping. The future of sublevel stoping seems relatively bright. GEOLOGICAL AND ROCK MECHANICAL BACKGROUND The rock mechanical conditions in Finland are in general relatively good and the rocks firm. The compressive strength is normally 40 - 150 Mpa and modulus of elasticity 40 - 200 Gpa. Low values are common in altered and fractured rocks and near the ore contact Rock stress measurements have been carried out already for 20 years for mine design and monitoring purposes. The results of these measurements show that relatively high horizontal stresses seem to be common (Fig. 2).

Jan 1, 1981

[ ]

Jan 1, 1938

By J. R. Mihalisin

THE application of electron-microscopic techniques to the study of high-temperature alloys has met with considerable success.' This is due, in part, to the submicroscopic nature of the phases present in this type of alloy making high resolution methods necessary. Among the newer electron-microscopic techniques, the extraction replica technique' has proven to be of great value. This method allows phases to be examined in situ in the microstructure and permits their identification by means of electron diffracticn. This technique eliminates the main disadvantage in using electrolytic extraction of residues as a means of phase identification; that is, the uncertainty of relating constituents identified in the residue to what is observed microscopically. In the course of work relating microstructure to physical properties in high-temperature alloys, it was found that the formation of grain-boundary carbide phases and intragranular precipitation of an age-hardening phase greatly influence strength and ductility at high temperature. In particular, it was found that the formation of a unique type of precipitate in Nimonic "80" (a nickel-chromium-aluminum-titanium type superalloy), termed cellular or discontinuous precipitate, at grain boundaries generally results in poor ductility at high temperature. However, this mode of precipitation can be avoided by proper heat-treatment. It was assumed that this precipitate was either a carbide or age-hardening type of phase. Using various etching procedures with the extraction-replica technique, it was found to be possible to extract the carbide and age-hardening phases preferentially in this type of alloy. Previous work has shown that the age-hardening phase can be extracted from superalloys merely by

Jan 1, 1959

By A. J. Opinsky, J. L. Orehotsky, L. L. Seigle

TUNGSTEN incandescent lamp filaments possess a typical structure of elongated crystals generated upon heating the silica-alumina doped wire rapidly to 2200°C or above.&apos; It is known that these very long grains exhibit a preferred orientation, but there is disagreement in the literature about the direction. Rosi,2 and later Rieck; reported that the <135> direction of the large grains in doped wire tends to be parallel to the wire axis, but other investigators have reported that <110> is the preferred direction. Some further investigation of the orientations of large grains in tungsten wire is reported in the following. In the first series of experiments, 6-in. lengths of wire were heated rapidly in a bell jar. Current was passed through the wires and within 15 sec the wires had reached the grain coarsening temperature. 2 min was the annealing time. Wires were heated in hydrogen, nitrogen, and vacuum. Later, wires were heated in an evacuated tube furnace in which the tube was brought from 1000°C to the operating temperature within 25 sec and held 5 min at temperature. Temperatures were measured with an optical pyrometer. After heating, the wires were electro polished and etched, and the orientations of the large grains determined by the Laue back-reflection technique. Most of the experiments were carried out on a single spool of 5-mil silica-alumina doped wire, but a few tests were made with 5-mil thoriated tungsten wire and 10-mil undoped wire. 5-mil silica-alumina doped wires were reduced to smaller diameters by electropolishing for one series of experiments. Orientations of the large grains in silica-alumina doped wire heated in various atmospheres are presented in Figs. 1 and 2 as plots of the direction of the wire axis relative to the cube axes of the crystals. For most of the conditions studied, the preferred orientation cannot be described as a single direction, but the points might be said to group themselves about the arc passing through <110> and <113>. This arc is the trace of the (211) planes and contains the <135> and <124 as well as <011> directions previously observed by other investigators. The preferred orientation of large crystals in silica-alumina doped tungsten wire might be most generally described, therefore, by stating that a (211 ) tends to be parallel to the wire axis. This is true also for wires reduced in diameter by etching and furnace heated, Fig. 2, i.e., the recrystallization texture is apparently unchanged upon removal of the outer layers and substantially independent of the temperature gradient within the wire.

Jan 1, 1962

By H. M. Strong, R. A. Oriani

THE technological interest attaching to light, age-hardening alloys for structural uses has been pointed out to one of us.1 A potentially interesting alloy would be titanium-rich Ti-Mg alloy, provided that sufficient solid solubility exists. or could be induced at high pressure. and provided also that age hardening can be induced by proper temperature and/or pressure annealing. It was decided therefore to explore the feasibility of producing a Ti-Mg alloy in the high-pressure apparatus. Experimental. Three high-pressure runs have been carried out. In each case the geometry of the sample was that of a cylinder of titanium of commercial purity, into which a narrow hole had been drilled along the axis; this hole was filled with magnesium wire,

Jan 1, 1967

Discussion of the paper of W. R. SHIMER, presented at the New York meeting, February, 1915, and printed in Bulletin No. 99, March, 1915, pp. 557 to. 585. WILLIAM R. WEBSTER, Philadelphia, Pa.-I would like to ask Mr. Shimer how the finishing temperature of the H-beams and other beams rolled on the Gray mill at Bethlehem compare with the rolling temperatures of the rails referred to in this paper. Also, how the reductions in the rolling of the beams compare with the reductions in the rolling of the rails. I would also like to know if any drop tests were&apos; made on the rails referred to as having been allowed to cool and then annealed; in other words, what results, if any, were obtained from tests on rails after the internal strains of rolling had been removed; and in the matter of the rail blooms, I would like to ask if they are not often heated to a higher temperature than is desirable on account of the thin flanges in order to carry the heat through to the finishing pass. The tensile strength of the steel in these rails is given as 125,000 lb. per square inch, which is almost as high as tire steel. If some of these blooms were rolled into rounds of about the same section as the head of the rail, would you not get better results from tension tests than those from the head of the rail? In other words, in rolling rounds, whether you would not be able to control the rolling and finishing temperatures better than is possible in the rail, owing to thin section of the rail flanges. Some years ago I had experience with the rolling temperatures of tire steel, running from about 127,000 to 133,000 tensile strength. These tires had the tensile strength and the deflection specified. One of the manufacturers had no trouble whatever, after a little experimenting, in meeting the conditions of the specification. Another manufacturer who made some of these tires came to the office and stated that he had tried tires from three heats of steel and could not meet the specifications and

Jan 5, 1915

By Frank S. Shuri

INTRODUCTION The Calumet Pumping Station, located on the south side of the Greater Chicago area, is part of the Tunnel and Reservoir Plan to accomodate the city&apos;s wastewater. The Station consists of two parallel rock caverns, each 18 m high, 20 m wide, and 62 m long, located in Silurian dolomite approximately 91 m below the ground surface. The caverns are oriented N-S with a 24-m-wide pillar between them. Prior to construction, rock mechanics studies were conducted in an L-shaped test adit at the location of the west cavern. The purpo3e of the rock mechanic studies was to characterize the site, particularly the in situ stress field and deformation characteristics of the rock. This information, together with other physical properties of the rock and geologic data, was used to evaluate the stability of the preliminary cavern design, with particular emphasis on cavern orientation, rock reinforcement, and pillar stability. GEOLOGY OF THE SITE Stratigraphy The Chicago area is located on the Kankakee Arch, a broad, gently sloping arch of Paleozoic sediments. Rocks in the project area consist of Silurian dolomites unconformably overlain by Pleistocene glacial deposits. The formations of interest to this study are: - Racine Formation, inter-reef facies. This dolomite is gray- brown, silty, and compact. It contains occasional prominent bedding surfaces. The Racine Formation in the project area varies from 73 to 74 m in thickness.

Jan 1, 1984

By L. M. Barker, E. G. Lewis

THE literature of milling is replete with papers devoted to the subject of ball milling, all of which no doubt have contributed in one way or another to progress in that art. In this paper reference will be made to only a few of the many authors, but the value of the contributions of all who have written on that subject is hereby acknowledged. With a few exceptions the efforts of most students of the subject have been devoted to laboratory investigations of principles. Davis1 was one of the first to report on plant-scale investigations and to present to mill men certain criteria for the guidance of ball-milling practices. His conclusions with respect to the significance of sizing analyses of classifier sands in their relation to the factors of mill speed and ball sizing are particularly referred to. Those conclusions were: I. If the balls are large or the speed of the mill is high, crowding will appear at the finer sizes in the classifier sands. 2. If the balls are small or the speed is low, crowding will appear at the coarser sizes in the classifier sands. 3. The indications are that best efficiency is obtained when the screen analysis of the sands show a minimum crowding at any size. The last conclusion was qualified by the statement that it had not been proved conclusively. It is surprising, however, that the literature of later years reveals little evidence that millmen have made any serious attempt to apply those criteria. This may, perhaps, be explained by the fact that the average plant-scale ball-milling problem presents so many variables that an investigation of any one of them encounters the problem of control of the others-a problem that often is unsurmountable in a small plant. In a large plant, in which there is a duplication of grinding units in parallel operation, opportunity may be afforded for determining the value of such criteria. Nevertheless, a study of published data from grinding circuits of both large and small plants suggests that either Davis&apos; criteria have been tried and found inapplicable or have never been given consideration. For the purpose of testing Davis&apos; conclusions and with improvement of ball-milling efficiency as the final objective, a test program was initiated in the concentrator of the New Cornelia branch of the Phelps Dodge Corporation early in 1938. The practices of that plant have already been described .2 The fine-grinding units are arranged so that any one of eight units may be operated as a test unite and its results compared with those of the remaining units. All units receive similar feed from a common storage bin, in which the product of the fine-crushing plant is bedded by traveling tripper. The ball mills are all similar in size and operated at the same speeds, and are individually metered. The feeder conveyors of each unit are equipped with Merrick weightometers. The test program as initially outlined proposed investigation of the following:

Jan 1, 1941

ARIZONA Tucson University of AriZona, Mining Engineering Society. B CALIFORNIA Berkeley University of California, Mining Asso. B University of California, Library. B & T Los Angeles Chamber of Mines and Oil. B Southern California Local Section. T Public Library. B & T Oakland Oakland Free Library. T San Francisco California State Mining Bureau. T Mechanic&apos;s Merchantile Library. B Mining and Scientific Press. B Stanford University Stanford University Geological and Mining Society. B San Diego Public Library. B COLORADO Boulder University of Colorado, Library. T Denver Bureau of Mines. B Colorado Scientific Society. B Mining American. B Denver Public Library. B & T Golden Colorado School of Mines Magazine. B Colorado School of Mines Library. T Colorado School of Mines Scientific Society. B

Jan 1, 1923

By F. Selig, A. S. Odeh

A second-order approximation to the exact solution of the diffusivity equation corresponding to the pressure build-up of a well producing at a variable rate is derived. This approximation is applicable when the well&apos;s shut-in time is larger than the total time elapsed since the well was first produced. The resulting equations are compact in form and easy to use. Thus, the need for Horner&apos;s&apos; theoretically precise but rather laborious solution to the above problem is eliminated. In addition, these equations apply where the use of Horner&apos;s widely known approximate method is questionable. From a practical point of view, the reported method is best suited for analysis of drill-stem tests and short production tests conducted on new wells. INTRODUCTION The utility of drill-stem and short production tests in reservoir studies has long been recognized by the reservoir engineer. If interpreted correctly they could lead to a wealth of information upon which may depend the success or failure of reservoirs&apos; analyses. Initial reservoir pressure and the average flow capacity are two quantities that are normally sought from a drill-stem and/or a short production test analysis. Pressures are the most valuable and useful data in reservoir engineering. Directly or indirectly, they enter into all phases of reservoir engineering calculations. Therefore, their accurate determination is of utmost importance. The flow capacity kh of the reservoir is indicative of its commercial capability. In addition, it can indicate the presence of a darnaged zone around the wellbore and, thus, the necessity for remedial measures. Of the several methods used to analyze drill-stem and short production tests, Horner&apos;s&apos; method is by and large the most common. It applies to an infinite reservoir and or a limited reservoir where the effect of production has not been felt by the boundary. Horner&apos;s method makes use of the so-called "point-source" solution of the diffusivity equation. The point-source solution is approximated by a logarithmic function and the superposition theorem is utilized to give the familiar pressure build-up equation where is the shut-in time, q is in reservoir barrels per day and the rest of the symbols conform with AIME nomenclature. Eq. 1 was derived for a well which produced at a constant rate q from time zero to time t and was then shut in. In actuality, such a constant rate of production does not normally obtain. Therefore, a correction must be applied to Eq. 1 to account for the varying rates of production. Horner suggested two methods. The first, which results in a theoretically accurate solution, is rather lengthy and laborious and, thus, it is not suited for routine analysis. The second which has been termed a "good working approximation" is the one used by the majority of the reservoir engineers. In the second method, Eq. 1 is modified by simply introducing a corrected time t, and writing where q is the last established production rate prior to shut-in, and t, is obtained by dividing the total cumulative production by the last established rate. Horner&apos;s original paper does not give any indication that this method of correction is based on any theoretical justification. In addition, there is a question as to what constitutes the last established rate. In case of a drill-stem test some engineers use the average rate obtained by dividing the total fluid produced by the total flow time, while others calculate the average rate by dividing the total fluid produced by the last flow-period time. Obviously, different results obtain for the different flow rates used. Because of this, a simple method to the varying-rate case was developed which is theoretically sound and which defines clearly the flow rate and its associated time to be used in the calculations. The final equation arrived at is where q* and t* are a modified rate and time, respectively, and can be easily calculated. In addition, it is shown theoretically that Horner&apos;s approximate method, if used for a variable-rate case, gives the correct pressure but would not be expected to give the correct flow capacity. MATHEMATICAL ANALYSIS The general equation governing the flow of slightly compressible fluid in porous media may be written as The elementary solution to Eq. 4, representing an instantaneous withdrawal of Q units volume of fluid at the origin at t = 0, is known as the instantaneous sink

By J. R. Maxwell

Large capacity flotation cells with volumes ranging in size from 300 to 2000 cu ft are used in the Opemiska concentrator, Opemiska Copper Mines (Quebec), Canada. This paper gives a description of the flowsheet with metallurgical comparisons using Maxwell vs. conventional cells, total power consumption used, and estimated maintenance costs.

Jan 1, 1973

By Phyllis A. Lyday

Jan 1, 1985

By H. A. Fisch, A. J. Opinsky, J. L. Bartos

Fort?-six- two-grain bounduries were studied in doped tungsten 1amp wire that had been heated to 3450°K very vapidly. Back-reflection Laue photograms were taken of the grain boundary partners and solved, using a computer. The resulting distribution of large-grain orientations was analyzed. Rotational axes were calculatedfor each grain boundary pair. The axes of least rotation show an anisotropy of rolalional angle. WhILE the orientations of large grains in straight doped tungsten wire have been studied extensively, little has been done to characterize the boundary that separates them. Rosi.1 upon seeing the jagged interlocking boundary in doped tungsten wire. inferred that the grains should have a preferred orientation, and proved it. He interprets his data as indicative of a single ideal orientation—(531)— being parallel to the wire axis. Rieck2, 3 and Mannerkoski&apos; have essentially confirmed this finding. Opinsky, Orehotsky, and Siegle argue that the data suggest that (211)—a plane-is parallel to the wire axis instead. This (211 ) contains the (531). and hence would appear to be a more general case.5 Ahlborn and wasserman6 report that their orientation data stretch from (110) through (531) to (311). This path is the locus of {211 Recently. Opinsky has suggested that the data can be interpreted as a series of ideal orientations that can be related by coincidence relationships to the (110) fiber texture. All these investigators have determined the orientations of the large grains by the back-reflection Laue technique, and they have all obtained similar results. Only Rieck5 as methodically looked at the large grains along a wire. He was apparently not concerned with the relationships of the large grains across their common boundary, but only with their individual orientations. This research was undertaken to fill this gap in the under standing of the mechanical properties of tungsten wire. Only the crystallographic aspects of the problem will be reported here. In addition, the large number of large-grain orientations, which was accumulated in this study. will also be analyzed. EXPERIMENTAL MATERIAL AND TECHNIQUES All of the data were obtained from four pieces of the same 7-mil-diam General Electric tungsten lamp wire. Twelve-inch lengths of the cleaned wire were heated in vacuum by the flick of a switch to 90 pct of the amperes necessary for fusion (a temperature of approximately 3450°K) and held for 1 min. On the basis of other data. it is estimated that the rise time is of the order of 0.5 sec. The four pieces of wire could have come from anywhere within about 18 ft of wire. Consecutive segments of each piece of wire were mounted in bakelite and polished metallographically The polishing procedure followed that described by woods. "nly boundaries between two grains that each occupied the entire cross section of the wire were photographed and X-rayed. The metallographic sample was mounted accurately with respect to the X-ray unit. Steps were taken to read the films as accurately as possible with the conventional Greninger net. The data were then entered into computer programs that solve the Laue film by precisely the same techniques that are used in the solution of the film by means of the stereographic projection. The use of the computer has probably shifted the main source of error from the stereographic plot to the reading of the film. On the basis of several experiments, it is thought that the error associated with the entire process, from mounting the sample through the computer solution, is of the order of about one-half degree. The output of the computer is the direction cosines of the fiducial direction (the wire axis) and the locations of the three cube axes. The former data were used to calculate the differences in orientation between the two grain boundary partners, and the latter were used in the calculation of the rotational axes that could bring the two grains

Jan 1, 1970

By Thomas L. Garwood, F. C. Menk

I T is generally accepted that no method of coal cleaning except froth flotation is effective in cleaning dust. In the majority of coals mined in the United States the dust sizes contain a high percentage of impurities, hence the removal of the dust from the coarse sizes lowers the impurity content of these sizes. Dedusted coal is desired as a means of providing a better feed to cleaning plants because of increased efficiency in both dry and wet plants. In dry-cleaning plants, a dedusted feed makes for a pervious and uni¬form bed. With a dusty feed the fines tend to segregate in the feed stream and pass en masse over the air separators, causing a lack of uniform aeration and fluidity of the bed necessary to efficient cleaning. In wet-cleaning plants deducting of the feed often decreases the sludge problem to the point of eliminating the necessity of wasting wash water. It may be advantageous to eliminate sludge-settling equipment in favor of dedusting equipment, to provide the advantages of a dedusted feed to the wet-washing process. Dedusting advantages may include: (1) the removal of fusain, especially advantageous in plants washing coal intended for metallurgical coke; (2) prevention of the gradual build-up of solids in the wash water, with a consequent variation in the washing ability of the system; (3) prevention of the loss of dust to the sludge ponds, providing instead a fuel for local consumption or special markets.

Jan 1, 1943

By H. l. Burghoff

THE presence of tellurium in copper and, by inference, in copper alloys, has been considered seriously detrimental and has been avoided. In particular, very small amounts of tellurium have been found to produce red-shortness, although the effects on cold-working and ordinary physical and mechanical properties have not been known so definitely. References in the literature are few, but as long ago as 1881, Egleston1 reported that 0.083 per cent tellurium in fire-refined copper rendered the copper red-short and therefore worthless for hot-rolling. In hot-rolling copper cakes containing this amount of tellurium, he found that fine cracks appeared in the cakes on the first pass through the rolls, the cracks opening further in successive passes. When cold, the metal was said to be tough and malleable. A few years ago, during the course of an investigation in our laboratory on copper-base alloys, it was found that tellurium-bearing alloys could be machined much more freely than similar alloys not containing tellurium. The study was pursued further in this direction, and considerable data were obtained, which indicated that certain tellurium-bearing alloys might have properties of commercial interest. The work eventually led to patent protection,2 a wide range of tellurium-bearing copper-base alloys being covered. This article presents results obtained on the effect of tellurium on the. mechanical properties of three copper-base alloys: commercial bronze (90 Cu, 10 Zn), 1.5 per cent tin bronze (98.5 Cu, 1.5 Sn), and silicon bronze (96 Cu, 3Si, 1 Zn).

Jan 1, 1937

By A. S. McLatchie, R. A. Hemstock, J. W. Young

Much attention has been given in the past few years to methods of increasing the recovery of oil from proven reserves. Numerous laboratories have made investigations to evaluate the possibilities of increased oil recovery by high-pressure injection of dry gas, injection of a propane slug followed by dry gas, solvent flooding. and by the injection at relatively low pressures of gases enriched with ethane and propane. Several years ago, Whorton and Kie-schnick&apos; published the results of laboratory studies on high-pressure gas injection which showed that, in the case of light oils, recoveries could be considerably increased by sweeping the reservoir with dry gas at pressures in excess of 3,000 psig. The increase was attributed by those authors to the vaporization of oil at the invading gas front and viscosity and solubility effects produced at the front by the invading gas. Later, Stone and Crump&apos; presented the results of a series of displacement experiments in which a light under-saturated crude oil was displaced from sand-packed columns with unusually high recoveries when the displacing gas was a rich condensate or a dry gas enriched with ethane or propane. They also conducted similar experiments at higher pressure on heavy undersa tu rated crude oil, although in this case the increase in recovery was not as great as in the case of the light oils. In both cases, viscosity reduction and swelling of the by-passed oil behind the invading gas front were believed to be responsible for the more favorable recovery of the original oil in place. Within the past year, other investigators", &apos; have presented the results of laboratory studies of miscible slug and solvent flooding recovery processes. This paper describes the laboratory methods developed for evaluating benefits to be obtained by enriched gas drive in specific reservoirs, and presents the results of several displacements of crude oils which possess a wide range of physical properties. The displacements were conducted at reservoir conditions of temperature and pressure. The apparatus used in the following experiments consisted of a sand-packed tube which served as the model reservoir, a cylinder of injection fluid, and a mercury pump. The stainless steel tube, 8 ft long and 0.53 in. I- was packed with a graded quartz sand. The high-pressure pump discharged mercury into the bottom of the injection fluid cylinder at a constant rate as low as 1 cc/hr. The average porosity and permeability of the sand column were 34.6 per cent and 3.25 darcies, respectively. In each case the tube was charged by the displacement of salt water by the reservoir oil under consideration. Recently a project was initiated to evaluate oil recovery by enriched gas drive from three oil reservoirs. Samples from a fourth reservoir (in this case high-viscosity oil) were studied with a view to obtaining recovery information of general applicability to low-grade, high-viscosity crudes. The oils from these four reservoirs exhibited a wide range of physical properties, and the reservoir conditions of pressure and temperature simulated in the laboratory represented several typical field conditions under which enriched gas drive might be employed. One of the reservoirs selected for laboratory displacement experiments produced an intermediate-gravity crude (29.6" API) by solution gas drive and a weak water drive. A low recovery in the range of 10 to 20 per cent was anticipated. Four displacement experiments were made to determine the effect of injection gas composition and initial gas saturation upon recovery of oil from the laboratory model. Two types of reservoir oil were used in these experiments. In the first run, a desaturated crude with a bubble point of 395 psi was charged to the tube. In the three subsequent runs, a simulated original reservoir oil was charged at 2,000 psi and produced by solution gas drive to 300 psi before beginning gas injec-

By R. C. Gifkins, A. Gittins

A. Gittins and R. C. Gifkins (University of Mel-houvne)— Evidence from somewhat similar experiments to those described in this paper has led us to the conclusion that possibility 2) of the four listed on p. 319 is a description of what happens in grain boundary sliding. That is, sliding is limited by accommodation deformation, it being necessary to the Continuance of sliding that this accommodation should take place. An example of such accommodation, though probably not the most important, is fold formation at triple points. The evidence and arguments for this point of view are set out in Refs. 14 to 16. In particular, an experiment with a lead bicrys-tall5 seems to support point 2) rather than 3). In creep of this specimen it was found that at least 90 pct of the extension of a zone 0.3 mm wide at the boundary was supplied by sliding at the boundary. The sliding was localized in a region at the boundary very much smaller than 0.3 mm, in fact, in a region too narrow to resolve optically. In poly crystalline Specimens&apos; there appears to be a surface effect, as found by Rachinger," but it appears that this may not manifest itself at low strains. "Low strains" means <10 pct for a Pb-TI alloy, <2.5 pct for magnesium or "Magnox" A12 alloy, or <40 pct for a 0 brass. Up to this extension the sliding, measured by the mean vertical step at boundaries, is proportional to extension. We are able to say this with some confidence, since the error bars on our points are statistically derived. Our results would lead us to think that the error bars on other work, including that of Mullendore and Grant, are much too large at low strains to show this

Jan 1, 1963