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By E. J. Harris

Mathematical solutions to complex mine ventilation problems are possible, but often the airway network is so complex that the mathematical solution becomes tedious and impractical. A fluid network analyzer, designed and built for analyzing mine ventilation problems has been in service at the Bureau of Mines' Pittsburgh station for approximately nine years. Using this analogue as a model, the mine ventilation network is simulated electrically by a combination of series and parallel circruits laid out to conform with actual mine airways. A tungsten filament lamp, referred to as a Fluistor, is used to simulate mine airway resistance. With the analogue ventilation model established, voltages of the proper amplitude to represent ventilating pressures are impressed across the circuit at points where mine fans and airshafts are located. Comparison of mathematical solutions of complex systems against analogue results showed a maximum variance of 3% for pressures and 2% for quantities. An electrical fluid network analyzer, designed and built especially for analyzing mine ventilation distribution problems, has been in service at the Bureau of Mines, Pittsburgh, for approximately nine years. It is a nonlinear, low voltage, fluid network analyzer of the type developed by the late Malcolm S. McIlroy, Professor of Electrical Engineering, Cornell University, who cooperated with G. E. McElroy, of the Bureau of Mines, in adapting the instrument to mine ventilation systems. Several modifications have been made since the original installation, but a considerable part of this paper is drawn from G. E. McElroy's original description of the analogue.' The analysis of water or gas distribution systems2,3 led to the development of this type of network analyzer. Several similar units are now employed by utility companies for this purpose; however, the Bureau of Mines unit is the only one designed specifically for mine airflow problems. Other airflow analogues employing a similar principle have been used at the Central Research Station of the Netherlands State Mines,4 in England,5 and in South Africa.6 Information on these devices indicated they were somewhat inflexible because commercial lamps with a sufficient range of resistance are difficult to obtain. Computers for mine ventilation analysis have been developed in Germany which instead of lamps use a variable resistance to adjust for turbulent flow laws. These units are expensive, but excellent results have been reported in their application. THE ANALYZER Theory of Application: As airflow generally follows the law of turbulent fluid flow, resistance to flow is nonlinear; consequently, the problem has been to find a nonlinear resistance element of suitable range that can be used for electrically simulated airflow. Tungsten filament lamps operated on alternating or direct current approximate the square-law resistance characteristics of mine airflow over a large range below maximum or rated voltage; that is, the voltage drop varies approximately as the square of the current. Consequently, the heart of the network analyzer is a nonlinear resistor known as a Fluistor, which is simply a custom-made low voltage, tungsten filament lamp that is available in a progressive series of relative resistance values ranging from 0.05 to 500 in nominal 5% steps. However, variations in manufacturing large groups result in differences of 1 to 3%, but series arrangements required for high-loss branches can be matched within about 1%. Utilizing a combination of Fluistors and load circuits, the mine ventilation system is duplicated electrically. Intake load circuits are connected from power intake to primary points of the circuit network; segments of unregulated flow along intakes and returns are represented by Fluistors, regulated splits and leakage paths are represented by load circuits and Fluistors of proper capacity; and mine exhausts are connected to ground from the last point of the network to complete the circuit. For the special purpose of representing booster fans or natural draft conditions, boosters or separate source circuits are provided that can be inserted between any two points of a network to increase voltage to the required value. Physical Layout: The analyzer consists of three 42

Jan 1, 1963

By T. A. Rickard

The notion prevails that writing is a knack, that the skilful use of the pen is a gift of nature. This is an error. Dogberry may be responsible for it; he said: "To be a well-informed man is the gift of fortune, but to write and read comes by nature". Because Dogberry said it, we may be sure that Shakespeare thought otherwise. Ability of any sort may be partly innate, but my own observation and experience lead me to conclude that most of the easy writers have become so by constant practice. As I recall the names of men successful with the pen, I remember that most of them have written a great deal and have taken particular pains to improve their style. The suggestion that proficiency in the difficult art is a happy accident provokes a sardonic smile. The larger part of the great writing in our literature is the result of persistent effort. An easy fluency has been the undoing of many; their flamboyant and fantastic scribbling has proved as perishable as froth. This criticism applies to technical writing also; in order that a technical description or discussion may hold the interest of the reader, at least long enough to cause him to read it to the end, the writing must be done carefully and systematically; otherwise it will fail in its purpose of conveying information. Clearness is absolutely essential. "It is not enough to use language that may be understood; it is necessary to use language that must be understood."* The purpose of writing, at least of that which is meant to be read by others, is not only to express ideas but to communicate them. Lack of perspicuity may prove as %ad as

Jan 1, 1931

By Oscar T. Marzke

Four alloys that precipitate the alpha phase from the beta of the copper-zinc system were heat-treated in various ways to develop as many forms of the segregate as possible. It was found that the precipitate may have the form either of plates or of needles. Plates usually result when precipitation occurs at low temperatures and needles when precipitation takes place at high temperatures. The needles tend to align themselves along certain planes in the matrix and to coalesce into plnte-like structures. The two phases were found to be related so that a (111) plane and [Oil] direction of the precipitate are parallel to a 10111 plane and 11111 direction of the matrix. DISCUSSION (E. A. Anderson presiding) D. W. Smith, Pittsburgh, Pa. (Written discussion).—Tllis report by Dr. Marzke covers completely all possible heat treatinents over a considerable range of compositiol~s in which a1pha precipitates from beta brass, and may be said to complete the Inctallographic part of this problern The lining up of ncedles of segregate to form plates, espeeially as shown in Fig. 5, appears to he regular, although the author's frequency plot in Fig. 11 makes it appear rather irregular. Has the author attempted anY correlation between some of the major dircetions and the oricntntaion of the parent grain as determined by X-ray analysis? Also, in Figs. 4, 5 and 6 the cross-sections of the needles appear to be straightsided and regular. Have these directions been correlated with the matrix latttice? Dr. Mnrzkr 's method of interpretation of the orientation rclationships between the alpha. and beta phases is a bit uncertain and seems to wed more explanation. If this relationship, as staited is such that :L (1111 plane and a [I 10] direction of that plane in the precipitate is parallel to a. {110} p1ane and a [111] direction of that, plane in the matrix, there mill be a maximum of 24 possible orientations of the alpha phase within a. single grain of the beta phasc. This relationship is expressed strercographical1y in Fig. 13, ill which the locations of a11 of the alpha {111} poles for the 24 orientations of alpha me given. Fig. 12 chccks fairly closely with this thcoretical plot,. with a few exeeptions which may be due to the inaceuracy inherent in the method used by the anthor in determining the orientations of the segregates. The method might have been refined somewhat had corrections been made for the displacement of the slip p1ancs upon deformation.

Jan 1, 1933

SAMUEL L. HOYT,* Minneapolis, Minn. -I was privileged to see the apparatus used by Mr. Scott, which is quite unique. It is, as the author says, a modification of the apparatus designed by Dr. Rosenhain, but it is evidently quite an; improvement. The author is to be congratulated on the fact that lie has given us, with his apparatus, a quantitative thermal analysis of these critical points. I notice the author refers to Ac3, Ac2, and Ac1. His designation of the Ac2 point is all right, but naturally in a steel with as much carbon as this, which would mean a hypereutectic steel, the other point might better be considered as an Ac, point with possibly another point above the Ac, point. Another important point brought out is the fact that, in Fig. 3, the lines representing the Ar1, transformation and the Ac,1_3 transformation do not intersect at the zero rate curve,

Jan 5, 1919

By S. K. Nicol, A. R. Swanson, J. C. Day

Addition of oil to a suspension of hydrophobic coal particles can influence its dewatering characteristics. An agglomeration process occurs in which coal particles are held together by negative capillary pressure at particle/oil/water contacts. Consequently, the units round which flow can occur are enlarged and this improves dewatering parameters such as drainage rate, solids recovery, and equilibrium moisture content. This paper discusses processes which attempt to use this principle, in terms of metallurgical and economic efficiency. The discussion is augmented by results of recent experiments on the effect of oil addition to centrifuges and vacuum filters.

Jan 1, 1980

By Gilbert P. Moore

Production in the Argentine in 1930 amounted to 1,415,099.7 metric tons, which converted into barrels of 42 gal., using the factor of 6.29, amounts to 8,909,773 bbl. This is a decrease of 481,613 bbl. from the 1929 production, which was 9,391,386 bbl. The production for 1930 was divided among three fields, as shown in Table 1. Table 2 covers Table 1.—Argentine Oil Production, 1930, by Fields Barrels Comodoro Rivadauia District Government........................................... 4,547,670 Railways Co........................................... 1,314,358 Astra-Eastern......................................... 1,016,024 Anglo-Persian......................................... 365,021 Solano Co............................................. 24,613 Dutch Shell........................................... 6,963 7,274,649 Neuquen District Government........................................... 569,245 Standard Oil-Argentina................................. 659,551 Astra-Eastern......................................... 8,234 Challaco Co. (Sol)...................................... 121,598 1,358,628 Salta District Government........................................... 90,576 Standard Oil-Argentina.................................. 185,920 276,496 8,909,773

Jan 1, 1931

By Om P. Garg

During the period between 1970 and 1974 the Iron Ore Company of Canada had embarked on a detailed program to evaluate all aspects of mine design work for its open pit mines around Schefferville, located both in Quebec and Labrador, Newfoundland, Canada. One of the main conclusions was that the majority of the slope angles for the ultimate pit walls could be steeped. During the period 1975 and 1976,five (5) open pit iron ore mines were redesigned using the steeper slope angles up to 55 degrees. Initially these pits were designed at slope angles varying between 37 degrees and 45 degrees due to the generally fractured and leached nature of rocks in the area. During the active mining phase between 1976 and 1979, the stability of the steeper ultimate pit walls was monitored. The mining of ore was successfully completed in 1978 and 1979 in three pits. This of course, resulted in a significant savings due to a reduction in the quantity of waste that had to be removed. The successful pit slope redesign project was a co-operative effort between the Federal Government, Universities and the Iron Ore Company of Canada.

Jan 1, 1983

By Carl J. Christensen

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

Jan 1, 1948

By Carl J. Christensen

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

Jan 1, 1948

By George C. Branner

BAUXITE is produced in Arkansas from two mining districts in the central portion of the State. These are (1) the Fourche Mountain district, immediately south and southeast of Little Rock in Pulaski County, and (2) the Bauxite (town) district, about five miles east of Becton in the eastern part of Saline County. These two mining districts are about twelve miles apart, separated by territory which, so far, has produced a negligible amount of commercial ore. Mining was by open-pit methods exclusively until 1924, when underground methods came into use. From 1924 to 1930 about 40 per cent of all of the ore produced in Arkansas was mined by underground methods, mainly by retreating caving.

Jan 1, 1935

By Owen S. Roberts

During the design phases of a conveyor system, the question arises regarding the type of drive required for each application. The paper shows that the correct drive for any particular application is the one that satisfies the criteria established for that application in the most economical manner consistent with such considerations as site location, availability of spare parts, area environmental conditions, power supplies available, etc. Following discussions of various mechanical arrangements for the drives, motor types and their characteristics are considered along with the control means of modifying these characteristics to satisfy individual requirements. These characteristics are all illustrated graphically. After selecting the motor and its starter, control accessories and interlocking arrangements as applied to material handling systems are discussed.

Jan 1, 1973

By R. M. Fowler, H. L. Hamner

DURING the last 25 years, there appeared in the literature a number of papers describing equipment and operating techniques for the determination of total oxygen in iron and steel. In the early papers, comparatively little attention was paid to side reactions that occur when iron is saturated with carbon at a high temperature in a high vacuum. As more experience was gained with the new method, the limitations appeared. Metals, with a boiling point lower than iron, distilled out of the crucible, condensed in the cooler part of the furnace, and subsequently reacted with carbon monoxide to form oxides and carbon. Aluminum, manganese, and the alkaline earth metals proved troublesome in this respect. Modifications have been devised to overcome the difficulties due to aluminum and manganese, while the alkaline earth metals are not of too much concern as yet to the steel chemist. The reactions of sulphur have received less attention, although it is generally recognized that some carbon disulphide is probably formed. Liquid air traps have been used in some cases to prevent any carbon disulphide from entering the analytical train. Sulphur was not a particular problem at the Union Carbide and Carbon Research Laboratories until the analysis of the irons of higher than usual sulphur contents became necessary. In order to describe the procedure developed for such irons, it will be necessary to first describe the type of vacuum-fusion equipment employed because the operation of vacuum-fusion equipment is an art to a considerable extent. At the Laboratories, vacuum-fusion equipment has been in daily operation since about 1930. Over the years, the evolution of this apparatus has been governed by the versatility required to analyze a wide variety of materials. Since all types of materials from high purity metals to slags are analyzed and, since seldom more than a few samples of one type are analyzed in succession, the apparatus was designed for accuracy and flexibility rather than for speed. A general view of the equipment is shown in Fig. 1, while Fig. 2 shows the relationship of the various parts. In Fig. 2, A is a vertical double-glazed 24X27/8 in. OD silica tube heated with a 20 kva mercury-arc high frequency generator. The tube is closed with a water-cooled brass head attached with de Khotinsky cement. A turret cap fits on this head and is sealed with a 1/8x3 in. "0" ring. The head contains a sight glass and two 8 in. horizontal glass tubes, for sample storage, cemented in with de Khotinsky cement. B is a four-stage Gaede mercury diffusion pump connected to the water-cooled head with a 11/2 in. copper tube through a flange with an "0" ring. The output of the vacuum pump feeds into an automatic Toepler F pump which compresses the gas sample over mercury in the measuring burettes, G and H. There are bypasses in this line for a McLeod gage C and a Piranni gage D, a manometer E, and for initial pumping out of the system with a Cenco Megavac backing-up pump. The reduction crucible shown in Fig. 3 is machined of Tungar Bulb quality (A.G.K.T.E.-2) graphite. The sample is guided into the crucible with the graphite funnel depicted on this figure. The arrangement of the crucible, radiation screens, etc. in the furnace is as follows: A 1 15/16x61/2 in. Alundum thimble, porosity RA-84, with two 1/8 in. holes near the top and opposite each other which take a pair of special tongs used for lowering it in place, is prepared. A 3/4 in. layer of powdered graphite is placed in this Alundum thimble, and the graphite crucible containing 20 g of ingot iron and 0.5 g of carbon is carefully centered on this bed of graphite powder and graphite powder is packed around it to the top of the graphite cru-

Jan 1, 1953

By T. H. Aldrich

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

Feb 1, 1912

By J. C. Purcupile, R. L. Morris

Present methods of roof support require that first a hole must be drilled, and then a toggle belt or grouted resin bolt be set. Automating this system is very difficult. Therefore, we decided to develop a system which would insert pins into the roof in one step. We think that this type of system can be automated much easier. It would then speed up the roof bolting operation and eliminate the need for a man to work under unsupported roof, making roof bolting a much safer job. There are two ways that a pin can be inserted in a mine roof without drilling a hole. It can either be pushed in, using a very high, constant axial force; or it can be hammered in like a nail. The former method involves very high compressive stresses in the pin, and requires complicated machinery to prevent buckling. Since hammering the pin does not require high axial forces buckling is not as likely. Also, experiments have shown that there are no problems associated with getting the pin to go in straight. We chose to develop the second method. While investigating methods for hammering a pin into a mine roof, we learned that piles were being driven 10 times faster than by conventional methods with a method called "orboresonance." We decided to turn the pile driver upside down, and drive pins up into the mine roof. Sonic Pin Setting Machine The machine consists of a steel bar supported at the nodal points of its first mode of transverse vibration (Fig. 1). A mechanical oscillator, driven by a hydraulic motor, is attached to one end of the bar. This provides the forcing function for the vibrations in the bar. The hydraulic power is supplied by a portable unit. When the forcing function is near the natural frequency of the bar, large amplitudes of vibration occur and require little power input. An anvil is attached to the bar at a point of maximum deflection, providing a means for striking the pin. Since the bar is being driven near its natural frequency, it takes little energy to accelerate the bar back and forth between each hit. This means that most of the power being put into the bar is going into driving the pin. This is unlike conventional pile drivers which use most of their power to accelerate the hammer back and forth between hits. The resonant frequency of the bar we used is about 250 Hz, which is in the audible range, hence the term "sonic pin setting machine." The system benefits are: (1) elimination of the two-step drilling and pin-setting roof bolt operation, (2) increased speed, (3) more intimate contact between the formation and bolts, (4) less expensive roof bolts, (5) higher integrity, (6) potential for automatic operation. Modifications During the months from Oct. to Dec. 12, 1974, under U.S. Bureau of Mines grant No. 00144104, "Projects on Coal Extraction," six members of the senior class at Carnegie Mellon University designed and built the experimental machine. They drove three pins into the Safety Research coal mine at Bruceton, Pa., and determined that the project was worth continuing. In January 1975 we began making modifications and repairs in preparation for a more extensive program of testing at Bruceton. The major items were: 1) Design and build a collapsible pin guide to keep the pin parallel with the line of travel of the lift table. 2) Move the anvil to the center of the bar. 3) Refinish the nodal holes and install new node pins and bushings. 4) Realign the bar in its frame. 5) Install a relief valve on the lift unit to control the upward force. The upward force that we exert on the pin is relatively small, so there is no tendency for it to buckle. This means that all we need to do is hold the pin straight during its initial penetration. This allows the bushing to travel up and down in a straight line. At the beginning of penetration, the bushing

Jan 1, 1977

The official Institute reports for the year 1929 were distributed in pamphlet form at the Annual Meeting, February, 1930, and were later included in Section 2 of Mining and Metallurgy, June, 1930, and thus made available to the entire membership. Membership In its report the Admissions Committee set forth the changes in membership during 1929, as follows: Total membership, Jan. 1, 1928, 8582; elected and placed on rolls in 1929, including 59 reinstatements, 509; loss by resignations in 1929, 88; loss by death in 1929, 110; loss by suspension in 1929, 37; membership at end of year not including Student Associates, 8856. Distribution of membership: Honorary Members, 16; Members, 6590; Junior Members, 38; Associates, 1041; Junior Associates, 1033; Rocky Mountain, 138; total membership, Jan. 1, 1930, 8856; Student Associates, 150; total including student associates, 9006. Treasurer's Annual Report, Year of 1929 Statement of Receipts For the year ended December 31, 1929 Dues: Arrears............................................ $ 3,501.75 Current............................................ 97,257.12 New Members...................................... 5,721.50 Advance........................................... 1,970.79 $108,451.16 Initiation Fees.................................................. 7,436.00 Magazine Receipts: Advertising Gross Receipts........................... $40,610.81 Magazine Sales..................................... 3,799.84 44,410.65 Sale of Transactions Current........................... $ 2,985. 15 Sale of Special Editions Current........................ 5,147.82 Sale of Back Transactions and Special Editions........... 4,186.93 Sale of Year Book..................................... 65.50 Sale of Authors' Reprints.............................. 2,585.40 Sale of Pins and Fobs.................................. 14.73 Sale of Technical Publications.......................... 1,451.55 Sale of Bindings...................................... 3,949.13 20,376.21 Net Interest Received: On Bank Balance and Temporary Investments......... $ 2,595.04 On Lie Membership Fund........................... 3,223.43 On James Douglas Library Fund...................... 5,425.61 On General Reserve Fund............................ 2,015.58 13,259.66 Miscellaneous Receipts........................................... 335.80 Total Receipts................................................ $194,269.48

Jan 1, 1930

By D. J. Schmatz, H. I. Aaronson, H. A. Domian

Diffusion kinetics in disordered hcp Cd-Mg alloys have been investigated by means of the Kirkendall effect and concentration-penetration curves determined with an electron-microprobe analyzer. Self-diffusion coefficients of both species were determined at the three marker compositions obtained, averaging 27.6, 46. 7, and 78.1 at. pct Mg, by means of the Darken analysis. These coefficients were then corrected for the unequal and concentration-dependent partial molar volumes of the two elements with the Balluffi analysis, and for the vacancy flux effect by the Manning analysis. The latter correction reduced the Balluffi correction produced larger changes in the self-diffusiv-ities; neither, however, produced statistically significant changes in the Do's or the H'S. The most striking result of this investigation is that at all three compositions and at all temperatures studied both the uncorrected and corrected self-difjusivities of magnesium are higher than those of cadmium. The Cd-Mg system is the first one found in which the higher melting, lower vapor pressure element diffuses more rapidly. Both an empirical correlation due to Toth and Searcy and considerations of the atomic mechanism of diffusion indicate that this anomaly is probably due to a comparatively low value of the activation energy required for a magnesium atom and a vacancy to exchange sites, perhaps occasioned by the higher compressibility of magnesium atoms. KIRKENDALL effect studies have been previously reported for only two hcp solid solutions: the E phase of the Zn-Cu system1 and the a phase of the Cd-Hg system.' In neither investigation were the marker-movement studies supplemented with the concentration-penetration curve determinations necessary to evaluate self-diffusivities by means of the atano and the Darken analyses. The present program was undertaken to obtain both types of data on a hexagonal solid solution in order to provide more detailed information relevant to the mechanism of diffusion in this type of lattice. The Cd-Mg system was chosen for this study because the disordered solid solution extends across the entire phase diagram at temperatures above 253"c5 and the substantial difference in the melting points of the component pure metals promised that marker movements would occur at reasonably rapid rates should the diffusivities of the two species be as unequal as might be anticipated. The experimental convenience of the relatively low melting points of cad-miun and magnesium and the availability of extensive and accurate activity data6 (required for application of the Darken analysis) were additional reasons for selecting this alloy system. Since the anisotropy of diffusion is not large in either pure cadmium7 or pure magnesium,' the diffusion couples were prepared from polycrystalline components. The presence of a well-defined texture in the couples—the c axis of individual crystals tended to be normal to the diffusion direction— however, provides a fair degree of crystallographic definition to the data obtained. The principal (and entirely unexpected) finding of this investigation, that magnesium, the high-melting low-vapor pressure element, diffuses more rapidly than cadmium, in contradiction to a broad range of results in fcc and bcc alloys, as well as in the previously studied hcp alloys,172 makes the self-diffusivity determinations of immediate interest in understanding the origin of this anomalous result. EXPERIMENTAL PROCEDURE The cadmium (Belmont Smelting and Refining Co.) and magnesium (Dow Chemical Co.) used in this study were both of 99.99 pct purity. Alloys containing 51.0 and 65.6 at. pct Mg were prepared from these materials by melting under a MgC12-base flux in a high-purity graphite crucible. These alloys were subsequently hot-worked and then homogenized in a helium atmosphere at temperatures close to their solidus points. Sandwich-type diffusion couples of the type g/d/g were prepared from the pure metals by solid-state diffusion. Two-piece alloy couples of Mg/65.5 at. pct Mg (Mg/gCd) and Cd/51.0 at. pct Mg (Cd/CdMg) were welded by a liquation technique. The individual components of both types of couple were initially cylinders 1.27 cm in diam and in length; the ends of these cylinders were machined accurately flat and parallel. For both welding techniques, the pure cadmium cylinders and the alloys were chemically polished in a mixture of 40 pct ethyl alcohol, 40 pct hydrogen peroxide (30 pct conc), and 20 pct nitric acid,g while those of pure magnesium were polished in a solution of 10 pct nitric acid in ethyl alcohol.' Immediately afterwards, both metals were rinsed in freshly distilled acetone, and then in similarly purified methanol.' The Mg/Cd/g couples were assembled in a carefully cleaned stainless-steel welding fixture, in which a screw operating through a self-centering arrangement permitted a controlled pressure to be exerted upon a couple prior to welding.'' Tungsten marker wires 0.005 cm in diam were placed at the d:g interfaces of some of these couples, and imbedded in the couples during the application of pressure. As soon as a couple had been assembled, the welding fixture was inserted into a Pyrex capsule containing a packet of zirconium chips at each end. The capsule

Jan 1, 1967

By V. R. Garfias

Although the work on which this paper is based was carried on by the writer as Special Commissioner of the Petroleum Department of the Mexican Government, the opinions expressed are only his personal views for which the Mexican Government can in no way be held responsible. Notwithstanding that the appointment covers all phases of the so-called petroleum question, as the one question of immediate importance was that relating to taxation, it was decided to devote all the time to this phase of the work. The present report has been divided into two closely related parts, the first dealing with the production and marine transportation of Mcxican petroleum, and the second, with the Mexican taxation on petroleum and its products. The writer wishes to acknowledge the loyal cooperation rendered by Mr. M. C. Ehlen, who had charge of the statistical work, and by Miss S. Stern and Messrs. E. P. Heiles and J. E. Morrissey. The aim throughout the work has been to pave the way for a thorough understanding between the Mexican Government and the oil operators and to present a true and clear statement of facts relating to the questions at issue. Mexican Oil Fields Development The salient features in the development of the Mexican oil fields may be summarized as follows: 1901. First commercially productive well in Ebano field. 1902. Tehuantepee field came in; Diaz Government granted concession to Pearson & Son on practically all Federal lands along the Gulf of Mexico. 1907. First producing well in the Furbero field. 1908. Dos Bocas well caught fire, advertising tremendous productivity of Southern oil fields of Mexico.

Jan 1, 1921

By Edward B. Walker, Michel Grosmangin

The geological and economic conditions peculiar to the Greater Oficina area are presented to demonstrate the necessity of a low-cost, well-site method of distinguishing gas-bearing formations. The method of gas detection with the neutron log is briefly discussed and its limitations are explained. A new method is described which consists in running a second neutron log with a larger source-to-detector spacing. Field data indicate that under favorable conditions the larger spacing response is proportionately more influenced by the virgin gas zone than is the shorter spacing response. One important condition is that the gas sands be invaded, with a diameter of invasion equal to about two to three times the hole diameter. The calibration of the longer spacing log is made so that the two logs read the same deflection in shale and in a known water or oil sand. Under such conditions, gas is indicated by a positive separation, i.e., the curve for the longer device is displaced to the right of the curve for the shorter device. Because of the non-linearity of the long spacing response, low porosity formations also show positive separations. In sands with large porosity variations, the gas sands can no longer he located visually. They can be detected on a plot of shorter spacing vs longer spac-ing deflections. INTRODUCTION In the Greater Oficina area of Eastern Venezuela, the rapid and accurate detection of gas from well logs is of primary importance because of a combination of economic, geologic, and operational conditions. Briefly, these conditions are: economic—there is no market for gas at the present time; geologic—a single well may contain as many as 30 or more oil or gas sands for which intervals -to be tested must be selected; opera-tional—first, once opened to the casing through perforations, gas sands are extremely difficult and expensive to squeeze off, and second, gas detection must be rapid because the geologist must decide immediately, at the well, which sand to perforate. During the early period of exploitation in Greater Ofi-cina, when clay base muds were used, sidewall samples, together with electric logs, gave fairly good distinction between oil and gas sands. When exploitation became concentrated on deep fields of poorer sidewall sample recovery, and after the advent of oil emulsion muds, now the standard drilling fluid in Greater Oficina, the regular neutron log became the most reliable indicator of gas. In 1953, R. Norelius devised the dual-spacing neutron technique for gas detection. The dual-spacing neutron log has proved to be highly successful in detecting gas and has been adopted as a regular survey by all of the oil companies of the area. Several hundred dual-spacing neutron logs have been run in Eastern Venezuela and several tests per well are available for positive evaluation of the logs. The findings outlined below are based upon this extensive field experience. GEOLOGICAL CONDITIONS OF THE GREATER OFICINA AREA The Greater Oficina area lies on the south flank of the Eastern Venezuela Basin (Fig. 1). Nearly all accumulations of oil and gas in the area are trapped, in whole or in part, against normal faults. All known oil and gas reservoirs in Greater Oficina occur in the Ofi-cina formation (Miocene-Oligocene) or in the "U" sands. The U sands are the lithologic equivalent of the Merecure group (Otigocene-Eocene), which contains oil in many fields north of Greater Oficina. Most of the petroleum produced in Eastern Venezuela is from the Oficina formation.

Jan 1, 1958

By H. F. Ramstad, F. D. Richardson

The equilibria (a) SiOz +Hz =SiO +H20 and (b) Si + SiO, = 2Si0 have beet1 studied at temperatures of 1425"to 1600°C ad 1310°to 1485°C respectively. The stattdard free energy changes for the tzrro reactions are given by the equatiotts Combination of the results for both equilibria leads to tiotz removes certain anomalies in existing high-terlzperature data for equilibria involving silica and silicon in iron. In many metallurgical processes and in many laboratory investigations silicon monoxide undoubtedly plays an important role. It is unfortunate therefore that wide differences exist between the results obtained by different investigators1-7 in their studies of such equilibria as In an attempt to put our knowledge of SiO on a surer basis, an exhaustive study has been made of equilibria [I] and [2] at temperatures ranging from 1300" to 1600°C. Reaction [I] was studied by measuring the amounts of silica which could be condensed from streams of Hz or Hz + HzO which had previously been brought into equilibrium with silica at temperatures ranging from 1425" to 1600°C. Reaction [2] was studied by measuring the material that could be condensed from streams of Hz or argon which had been brought into equilibrium with mixtures of silicon and silica at temperatures ranging from 1310" to 1485°C. EXPERIMENTAL Materials. The silicon was "superpure" grade and contained less than 0.1 pct impurities. The silica was prepared from pure mineral quartz; this was crushed and treated with concentrated hydrochloric acid to remove particles of iron, washed with water, and finally dried at 120°C. For the hydrogen + silica reaction, the silica was sized to —20+100 mesh. For the silicon + silica reaction, the two materials were ground to a fine powder in an agate mortar. The hydrogen and argon were commercial oxygen-free gases. The gas streams were controlled with capillary flow meters and the volumes were measured by wet gas meters. After passing through the meters, the gases were partially dried by silica gel. The hydrogen for the HZ + SiOz reaction was then passed through palladised asbestos at 300°C and dried with magnesium perchlorate. The efficiency of oxygen removal was checked throughout the experiments by passing the gas over an electrically heated strip of nichrome, used as an indicator as described by Rathman and de itt.' When mixtures of HZ + Hz0 were required, the partial pressures of water vapor (1.8 to 22 mm) were obtained by passing the hydrogen through oxalic acid dihydrateg' lo held at various controlled temperatures, O.l°C, by means of a water bath. The hydrogen for the Si + Si02 reaction was purified by passing it over a mixture of 3 parts of magnesium to 5 of lime heated to 600°."l1 u The argon for this reaction was passed through titanium powder (-3/16 in. + 100 mesh) heated to 900°C. The nitrogen used to prevent the reaction products escaping from the condenser (see later), was deoxidized by copper or iron at 600°C. All these gases were finally dried with magnesium perchlorate. Furnace, Temperature Contr01, and Measurement A molybdenum resistance furnace was used for both sets of experiments. The reactions were conducted inside a high-grade alumina tube, 36 in. long and 1 in. in diam as indicated in Fig. 1. With this arrangement an even temperature zone (2"C) 4 cm long was satisfactorily obtained. The temperatures were kept constant by means of a proportional controller actuated by a Pt-Pt 13 pct Rh thermocouple. This was placed between the two alumina tubes, so that the temperature at the junction was 1400" to 1450°C. Up to 1485"C, the temperatures were measured with Pt-Pt 13 pct Rh thermocouples. For higher temperatures an optical pyrometer was used, this being sighted (through the glass window 1 in Fig. 1) on the end of the alumina tube, that held the SiOz or Si +SiOz mixture, 10 in Fig. 1. The optical pyrometer was recalibrated whenever a change was made in any part of the apparatus situated in the hot zone. Successive readings with the optical pyrometer were reproducible to within 1"C. Equilibrium Apparatus and Procedure. Hydvogen and Silica Reaction. The apparatus is shown in Fig.

Jan 1, 1962

By R. E. Lindstrom, D. G. Peterson, H. J. Heinen

Alkaline alcohol solutions were investigated by the Federal Bureau of Mines for improving the desorption rate of gold and silver from metal-laden activated carbon generated in gold processing circuits. Factors affecting the desorption, such as temperature, alcohol content, type of alcohol, and alkalinity, were studied. Nearly complete metal desorption was obtained in 5 to 6 hr at 80º C using a solution containing about 20 vol-pct alcohol and 1 pct sodium hydroxide. Sodium sulfide was shown to be effective for selectively precipitating silver from the carbon strip solutions, thereby providing a means for producing high- purity gold by subsequent electrolysis.

Jan 1, 1976