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By E. A. Nichols

The purpose of this paper is to present a contour map that shows the geographical variation in geothermal gradients in the Mid-Continent and Gulf Coast oil fields. Introduction Frequently there arises the need for an estimation of the temperature to be expected at a predetermined depth in working with a wildcat or in deepening old production into 'Ones that are relatively unknown. The study of geothermal gradients in oil fields has been made previously by many investigators. One of the pioneers in this work was C. E. Van Orstrand,' who, as well as most of the other investigators, was primarily interested in the relation between temperature and depth in a given locality. Between 192r and 1929, American Petroleum Institute Research Project NO. 25 fostered a thorough study of earth temperatures.2 K. IV. French did some work in California, the results of which were published in 1939.3 In most of these studies, an attempt was made to correlate temperatures in a rather localized area. This paper will show the results of an attempt to correlate temperature gradients over rather large Portions of the Mid-Continent and Gulf Coast area. Method of Obtaining Data It has been found that for complete thermal equilibrium to be established in a well, the well must stand undisturbed for a period of several hours to several weeks, depending upon the way the well was produced prior to the shut-in period. The data in this paper were obtained in conjunction with running pressures in wells or in taking samples of reservoir fluid. Glass maximum recording thermometers were used in all but a few instances. The wells had been shut in from one hour up to I. or 12 days. Since the wells were normal producing wells, some of the shut-in times undoubtedly were insufficient for complete thermal equilibrium to have been established and the temperatures measured do not necessarily represent the true earth temperatures. They do represent the temperature conditions that will be encountered in a well that is producing oil. The data, therefore, can be useful in working with or in estimating the temperatures to be expected in producing reservoirs. In obtaining a thermal gradient by dividing the difference in temperature of the formation and the mean annual surface temperature by the depth of the formation, one is assuming the depth-temperature line to be straight. Depth-temperature curves are almost straight lines (Fig. I). However, on close examination of accurate data, a slight curvature usually is observed. Most wells yield curves with slopes increasing with increasing depth. These curves are believed to be from wells that are in and are underlain by sedimentary material. Some few curves have slopes that decrease with increasing depth. These curves are believed to be from wells that are underlain rather closely by granite or some other igneous rock. Most investigators

Jan 1, 1947

By R. D. Satterley

The Sherwood mine is an iron-ore mine owned and operated by the Inland Steel CO. in the Iron River district of the Menominee Range in Michigan. The property consists of an 80-acre tract in the village of Mineral Hills, about a mile north of the city of Iron River. The Ore mined is a reddish brown, nonbessemer hematite and limonite. The ore bodies lie in a large syncline having an east-west strike and are associated with a rock structure that is folded in a complex manner. The two 40-acre tracts run north and south and the shaft is at about the center of the north forty. The shaft is 1286 ft. deep, with the principal operating level at a depth of 1000 ft. from surface. A new level at a depth of 1200 ft. is in process of development. The ore body at the 1000 ft. level is east and west at approximately the line between the north and south forties and at this elevation is from 50 to 250 ft. wide and extends above the level at varying heights of from 50 to 250 feet. The 1000-ft. haulage drift extends south from the shaft, through the east-west ore body to the slates on the south side of the body. The ore body was intercepted in the drifting at about goo ft. from the shaft and was about 200 ft. wide at that point. A crosscut was extended to the east and west property lines along the south boundary of the ore body. This east-west ore body is laid out in areas go ft. wide for stoping with pillars 40 ft. wide. With this plan a stope is approximately 80 by 200 ft. and has a pillar on both sides that is approximately 40 by 200 ft. The ore has a height of from 50 to 250 ft. above the elevation of the level, therefore the height of the stopes varies in accordance with the height of the ore body at each location. From the crosscut, two main raises, each 6 by 7 ft., are put up into each 80 ft. stope area (Fig. 1). One of the main raises serves as a manway and the other as an ore raise, through which the ore is transferred from the stope to the tramming equipment. The original layout as for scraping of the ore from under the stopes into the ore raises. The ore raise is put halfway (east and west) along the 80-ft. stope area and usually is in iron formation. The manway and ore raise are on approximately 15-ft. centers. These main raises are Put up to a height of from 22 to 30 ft. above the level floor, then from the toll of the ore raise a scraper drift (8 X 8 ft.) is driven across the width of the ore body, which is in the neighborhood of 200 ft. From the scraper drift, mill raises are put up at 12½-ft. centers, staggered on opposite sides of the drift, and these are extended 23 ft. above the elevation of the scraper-drift floor. The sublevel connecting the top of these mill raises is called a mill "sub." Other sublevels are developed parallel to the scraper and mill subs at 25-ft. vertical intervals above the mill sub. The mill sub and the other subs above the mill sub are known as sublevels or dog drifts, and are 4 ft. wide and 6 ft. high. These dog drifts

Jan 1, 1946

By Frederick N. Rhines

BECAUSE of the nature of the environments in which metals are handled, it is natural that gases should be suspected of intruding into metallurgical operations, there to produce effects both beneficial and detrimental. The problem of tracing and controlling such effects is often made difficult by the complexity of the conditions surrounding 'their occurrence, even though the fundamental mechanisms involved may be simple and of familiar type. Many gas-metal reactions are known to be implemented by processes of diffusion. These form a homogeneous group of phenomena which become more readily understandable when viewed together, in that the knowledge gained from one serves to interpret the next. It is the purpose of the present paper to present, by means of examples drawn from practice, a brief survey, of the ways in which gas-metal diffusion serves and obstructs the purposes of the metal-fabricating industries. The selection of the cases described was made by consulting more than thirty-six practicing experts whose combined experience provided an extensive coverage of the field and who were in a position to supply examples of occurrences of present day interest. The response was generous and it is regrettable that space permits the description of only a limited number of typical examples with but brief mention of parallel cases. THE NATURE OF GAS-METAL DIFFUSION The term "gas-metal diffusion," although commonly used, is ambiguous in so far as it implies that a definite group of substances may be identified as gases and may be expected to behave in a manner distinct from other substances in association with metals. "Gases" such as oxygen and hydrogen when diffusing through a liquid or solid metal are properly components of the liquid or solid solution; they behave as alloying elements and are not to be distinguished in their diffusion characteristics from other elements, except that each has an individual rate of diffusion. On the other hand, a number of metals in certain temperature ranges are volatile to the extent that they may appear in the form of vapor in metallurgical operations. For the sake of greater definiteness, therefore, it will be convenient to- regard as "gas-metal diffusion" any process in which the result depends upon one or more of the diffusing elements appearing, at some stage, in the gaseous state, or as a compound gas. No element, gaseous or otherwise, can diffuse through a liquid or solid metal unless it is at least slightly soluble in that metal. The elements of low atomic number

Jan 1, 1944

By R. R. Sayers

VENTILATION may be defined as the process by which vitiated air of an inclosed or partly inclosed space is continuously replaced by fresh air. Fresh air has been defined as invigorating pure air. Pure dry air at sea level contains the following gases:1 Analysis of Air at Sea Level PER CENT. Oxygen 20.94 Nitrogen 78.09 Carbon dioxide 0.03 Argon 0.94 Helium, krypton, neon, xenon, hydrogen, hydrogen peroxid, ammonia, ozone traces CARBON DIOXIDE LIMIT For many years carbon dioxide was used as an index of the purity of the air vitiated by the metabolism of people. It was, however, well known that the untoward effects produced on those exposed to such air was not due to the concentration of the carbon dioxide. It has been found that the untoward effects on the comfort and efficiency of those so exposed are due to the increased temperature and humidity. It has been found that men can breathe air containing many times the amount of carbon dioxide found in our worst ventilated theaters and assembly halls, which, according to Rosenau, do not contain above 0.5 per cent. carbon dioxide.

Jan 7, 1926

By R. J. Sullivan

DURING the past twelve months the Loudon pool of the Eastern Interior Coal Basin has become established as one of the two largest discoveries since the revival of exploitation in the Illinois region and now occupies a position among the important pools of the United States. On Aug. 1, 1939, production averaged 54,000 bbl. per day from 990 wells, having accumulated a total of 10,305,000 bbl. Its very active develop-ment promises to continue for fully another year. It is the site of one of the industry's most singular large-scale gas-injection programs. LOCATION AND RESERVOIR CHARACTERISTICS At present the pool embraces an area 15 miles long by 3 ½ miles wide in eastern Fayette County, along the western rim of the now well-known Illinois Basin's deeper part, through townships 6, 7 and 8 north and ranges 2 and 3 east of the Third Meridian. It is the northernmost, and most prominent, productive structure of a group extending over a 50-mile trend southward to the Dix pool of Jefferson County. Three horizons have been proved to carry production-namely, the Weiler sandstone at 1390 ft., the Paint Creek sand at 1460 ft. and the Benoist or Bethel, at 1500 ft. Geologically, they fall in the Chester series of the upper Mississippian system, where much of Illinois' early-day oil was found, having been laid down in shallow off-shore waters as a part of the vast delta deposit underlying central Illinois and parts of Indiana and Kentucky. As a result of this type of sedimentation, followed by repeated uplifts and warping along an anticlinal axis, differ-ential deposition of sands and shales contributing to great irregularity took place. This is further reflected by wide variations in permeability, porosity and thickness of all the sands and, accordingly, in the producing characteristics of wells. Permeabilities range as high as 550 millidarcies, with the average commonly lying between 60 and 100. For the three pay horizons the mean porosity is 18 per cent, at a calculated water saturation of roughly 30 per cent. The Weiler sand has an average thickness of 25 ft., the Benoist of about 23 ft. and the Paint Creek of approximately 18 ft. Of these three productive formations the Benoist

Jan 1, 1940

By A. W. Doepke

CLIMAX is situated in the heart of the high Rockies at Fremont Pass on the Continental Divide. This setting naturally throws some of the romantic aura of the old mining camps around the town. In its early days it was much like them, even to its air of impermanence. Its founders had faith in the future-as did every adventurer who started a hole in the ground and called it a mine. In those days, however, all available money was expended on the mine, and those who labored on the job had to he content with rugged living arrangements. The visitor at Climax today. however, sees a townsite carefully laid out to enhance the natural' beauty of the surroundings. There are 250 houses and 43 apartments which have been carefully designed by an architect, and missing is the long line of houses of the same type. Every house is of a different design, all being modern in every respect, with haths, running water, electricity, and .sewage disposal. They vary in size from three to six rooms and rent for $5 per room per month. A complete, well-designed water-treatment plant supplies water for domestic purposes.

Jan 1, 1946

By A. P. Young, F. C. Holden

IN many of the early investigations of the aging of titanium alloys, it was observed that the retained beta phase could be aged to a high hardness without an apparent change in microstructure; moreover, in some alloys it was found that even a very rapid quench produced beta having an anomalously high hardness. What appeared to be hard beta phase was designated as "beta prime," to distinguish it from the softer normal retained beta phase. Frost and co-workers'.' demonstrated that the increased hardness is caused by the formation of a metastable phase, omega, which can be identified from its X-ray diffraction pattern. This reaction also has been studied by Brotzen, et a1.,3 and the structure of the omega phase has been published by Silcock, et al.," and by Austin and Doig.3 The X-ray diffraction analysis by Austin and Doig indicated that omega is low in alloy content, approaching the composition of the stable alpha. The aging process proceeds by the path Thus, overaging results in the formation of alpha and the ultimate disappearance of omega. This is accompanied by a decrease in hardness and a recovery of ductility. The present work represents a study of the aging process in a high-purity Ti-6.4 Mn alloy, in which optical and electron microscopy, X-ray diffraction, and hardness data were correlated. The specimens, 1/8-in. sections cut from 1/4-in.-diam rod, were heated in argon to a temperature just into the beta field (810°C), held for 1 hr, and water-quenched. The aging samples were heated in air for 1 hr at 300 to 500°C. The specimens were ground and mechanically polished, finishing with alternate etching and polishing on a slow-speed wheel to remove disturbed metal from the surface. The surface finally was swab-etched, rinsed with tap water, and air-dried. The etchant used was an aqueous solution containing 1 1/2 pct HF and 3 1/2 pct HNO3. This procedure is identical with that used for preparing metallographic specimens, except that the optimum degree of final etching required for electron microscopy may vary from that used for light microscopy. Metal replicas, backed with silica, were prepared from plastic strip-pings for examination with the electron microscope. Complete details of the procedures used for preparing these replicas are available elsewhere." Fig. 1 shows a comparison between the structures revealed by the electron microscope and those obtained by conventional light microscopy. Hardness and X-ray diffraction data are listed in Table I. No evidence of a second phase is apparent in the optical micrographs for the as-quenched sample, or for the specimens aged at 300 or 400°C; fine alpha particles can be seen in the specimen aged at 500°C. In the electron micrographs, visible equiaxed pocks appear in the as-quenched specimen, and, with increasing density, in the samples aged at 300 and 400°C. After aging at 500°C, the structure becomes markedly coarser and develops an oriented appearance of a second phase, coincident with the appearance of visible alpha particles in the light micrographs. These observations are confirmed by X-ray diffraction and hardness data. In these specimens, aged for 1 hr, the intensity of the omega pattern increases to a maximum at the 400°C aging temperature, corresponding to maximum hardness and the maximum density of pocks in the electron micrographs. At this point the beta phase shows a definite enrichment in Mn. At 500°C, little or no omega re-

Jan 1, 1959

By D. B. Masson

THE martensitic transformations occurring in ,B AgCd as a result of cold working at room temp.. a-ture and cooling below room ten1erature have been reported by Masson and Barrett.1 These authors found that simple cooling to 127°K caused body-cen-tered-cubic AgCd containing 53.0 at. pct Ag to transform to an orthorhombic structure, while mechanical deformation at room temperature was found to induce a hexagonal structure. Furthermore, they observed that the temperature at which martensite first appeared on cooling, Ms, and that at which the transformation was complete, MI, as well as the corresponding temperatures for the reversion on heating, As and Af, could be ascertained to ± 1°K, although they report these temperatures only for the alloy containing 53.0 at. pct Ag (51.96 wt pct). In the work reported here the temperature range of the transformation on cooling was studied as a function of composition, and further consideration was given to the relationship between the original bcc structure and the transformation-induced hexagonal and orthorhomic structures. EXPERIMENTAL PROCEDURE All samples studied were in the form of annealed 300-mesh powder and were prepared from the constituent metals in the manner described previously.1 The compositions in weight and atomic pct are listed in Columns 1 and 2 of Table I. Method of determination of transformation temperature was the same as utilized previously1—measurement of the intensity of X-rays diffracted by the transformation product. A diagram of the low-temperature sample mount is shown in Fig. 1. This mount was made to fit a GE model XRD-3 X-ray diffraction unit. The powder sample was varnished to a flat surface on a copper sample holder at A. This sample holder was soldered to a brass rod, B, which was in turn soldered to a second copper rod, C. Rod C could be cooled to 78°K by inserting it into a reservoir of liquid nitrogen, D. A heater coil of nichrome wire was wound at E on the sample holder, and by varying the current through the heater a thermal gradient could be maintained along brass rod B. Sample temperatures from 78°K up could be attained and held as long as needed. The sample holder and nitrogen reservoir were insulated by Styrofoam, F, and the sample itself was protected by two radiation shields, G. The X-ray beam entered and left the sample chamber through windoys in the supporting container at H and I. Sample temperatures were measured by a calibrated copper-constantan thermocouple varnished to the sample holder just out of the beam at A. The low-temperature structure had been found to possess orthorhombic symmetry1 and the expected positions of the diffraction maxima were known. Therefore the sample was aligned in the X-ray beam and the Geiger counter of the spectrometer set to receive the most intense orthorhombic reflection without an adjacent interfering cubic reflection. This

Jan 1, 1961

By Oliver S. North

Reserves of perlite rock in the western section of the United States are immense. A geological report prepared for the Union Pacific RR showed proved tonnage of over 400 million tons in southern Nevada alone. Yet the perlite industry is not large, and most of the mines are relatively small. There are indications that perlite processing, thus far largely in the hands of relatively small com¬panies, is becoming concentrated in a few large companies. For economic reasons the bulk of perlite sold in crude form has come from three or four pro¬ducers, although many individual operators have sold small quantities to limited lists of purchasers. Perlite is one of ultra-lightweight aggregates. Owing to its outstanding qualities as an aggregate, variety of uses, and ultimate economy of use, it has enjoyed considerable popularity in this country in recent years. Marked foreign interest also has been evinced in this material.

Jan 2, 1955

By Maurice Rey, H. Brevers

THROUGH circumstances connected with the war, the senior author lost his records therefore it has been impossible to include numerical data in this paper. The arsenical quicksilver ore investigated had been roasted, with poor metallurgical results. The vapor-tension temperature curves of mercury and arsenious trioxide are similar, and the arsenical compound hampers the coalescence of mercury drops in the condenser and is the cause of large stack losses. The ore was a gray limestone carrying small amounts of carbon and mineralized with cinnabar and two arsenic minerals, realgar (As2S2) and arsenopyrite (FeAsS). The proportion of realgar often exceeded that of cinnabar; the proportion of arsenopyrite was smaller. The grade of the ore varied between 0.8 and 4 per cent Hg. The problem was to make a high-grade mercury concentrate, as free from arsenic as possible. The water used throughout the testing was hard, having a pH- of about 8. FLOTATION OF REALGAR Realgar showed a very strong tendency to float. It formed a film at the surface of the pulp and floated in abundance with only pine oil. Therefore an attempt was made to float the realgar before the cinnabar, but this was not very successful; the percentage of mercury in the realgar concentrate could never be brought below 2 or 3 per cent. Cinnabar slimed easily and floated with pine oil, so that some of it always accompanied the realgar. There was also the question of the cinnabar-arsenopyrite separation. On further investigation it was found that realgar can be floated not only with pine oil but even better with a combination of hydrocarbons and pine oil. Washing the ore with ether revealed that it contained hydrocarbons, which helped to float the realgar. In this connection it belongs to the same class as carbon, sulphur and talc. It can be floated also with a xanthate, when activated by a heavy-metal salt. The conditions favoring the two types of flotation are opposed, as activation by a copper salt facilitates xanthate flotation (in fact, is even necessary to it), whereas it hinders pine oil and petroleum flotation. One type of flotation can be termed nonpolar and the other polar, a distinction that has been stressed in a previous paper. DEPRESSION OF REALGAR AND FLOTATION OF CINNABAR Many chemicals were tested in an attempt to float the cinnabar and depress the realgar. Finally starch rendered soluble with caustic soda was tried, also several grades of commercial soluble starch, and dextrin was found to be the best and the most convenient reagent. Several of these starch preparations have a strong flocculating effect on the pulp, which is a distinct disadvantage. Dextrin, with its low flocculating power, is excellent. It is noteworthy that starch preparations are also depressants for carbon and talc, so that the fact apparently has a general

Jan 1, 1941

By Francois E. Heuze

The Crestmore Mine of the American Cement Company lies at the eastern end of the Jurupa Mountains, 50 miles east of Los Angeles. Originally, a quarry was opened in 1908 for "limestone" used in the manufacture of cement. The mining operations eventually went underground employing first a modified system of block caving and later the "room and pillar" scheme. The limestones are relatively small roof pendants preserved in an enveloping and intrusive quartz diorite. They occur as two irregular lenticular bodies roughly parallel at the top and tending towards convergence at depth. Their dip varies between 25 and 30 degrees E. The presently mined lower bed, Chino limestone, is typically composed of alternating bands a few inches to a few feet thick of medium to coarsely granular white crystalline limestone and somewhat yellowish limestone (brucite marble). A "room and pillar" scheme of mining is currently employed in the lower body of the Crestmore Mine. The levels are horizontal and access is provided by a spiraling road starting in the old quarry. The present depth of operations is an average 750 ft below the surface. Fig. 1 gives a three-dimensional general sketch of the mine. The long axis of the rooms is in an E-W direction, normal to the strike of the beds. Fig. 2 is a horizontal map of the 130 level, the deepest level mined presently. It is in this level that most of the in-situ investigations have been conducted. The present investigation was made possible by a non-restrictive grant of the American Cement Company to the University of California. The program included a series of in-situ tests using flat-jacks, plate bearing,

Jan 1, 1968

By Pieter W. Greeff, Graeme W. Mitchell

INTRODUCTION This paper describes the underground environmental planning parameters developed for Pancontinental Mining Limited's Jabiluka uranium deposit. The deposit is located 230 km east of Darwin in the Alligator Rivers region of the Northern Territory, Australia. The deposit is situated within land subject to an Aboriginal land claim, adjacent to a National Park and within a proposed extension to that National Park, as well as being close to a long- established Aboriginal reserve. In addition, being the first large underground uranium mine planned in Australia, the environmental considerations, both on surface and underground are considerable. Pancontinental is committed to the highest practicable standard of environmental management in the operation of the mine. In addition, Government regulations and requirements are particularly stringent by world standards. The underground environmental problems are discussed later in the paper with emphasis placed upon radiation aspects, both gamma and radon daughters, and dust. Consideration has also been given to heat and humidity due to the location of the deposit in a sub-tropical region 12° south of the equator. The paper explains how these environmental factors influence the design and selection of stoping methods. GEOLOGY AND ORE RESERVES The Jabiluka Two orebody is completely overlain by flat-bedded Kombolgie Sandstone with a thin layer of surficial colluvial sands. The orebody occurs in an east-west striking folded succession of Lower Proterozoic metasedimentary rocks of the Cahill Formation. Uraninite and pitchblende constitute essentially all the uranium mineralisation and are contained in the four lithological series, as shown in Fig. 1. - ,Upper Graphite Series - Main Mine Series - Lower Mine Series 1 - Lower Mine Series 2 The succession at Jabiluka has been folded and forms an east-south-east striking, asymmetric syncline-anticline which dips south and plunges to the east. A major fault bisects Jabiluka Tw8 having a north-south trend and dipping about 80 to the west. A near vertical tourmaline granitic pegmatite dyke up to 30 m in thickness has intruded the Jabiluka Two orebody at the western end. Current drilled ore reserves for Jabiluka Two are 52.0 million tonnes at 0.39% U308. Included in these reserves are 1.1 million tonnes of gold ore at 10.7 g/tonne. A large proportion of the orebody can be mined in thick sections (over 80% of tonnage) either as single sections or by bulking a number of thin sections which are close together.

Jan 1, 1981

By H. W. Gillett

Many of the parts of motor cars, aircraft, etc., that require strong light construction, hence must be made of high-quality steel, are stressed to the maximum limit only in a very small volume. In parts subject to bending stress a line or even a point may take the maximum stress. A series of endurance tests under repeated bending in progress in the U. S. Bureau of Mines laboratories, like similar tests by other investigators, has shown the great difference in life of sister bars of the same stecl, handled in the same way and tested at the same nominal stress. It is known that a surface notch or scratch greatly increases the local stress over the nominal calculated stress; internal notches, such as those formed by inclusions or sonims, probably have a similar effect. From the tetss made by the Bureau of Mines, the cleanliness of the steel at the dangerous section, or point of maximum stress, seems to be one of the most important factors in determining the life of the piece. The more localized the stress, the more does chance, rather than the average properties, dctermine the life of the steel. The usual test, a tension test of a bar taken longitudinally, is not sensitive to the local drop in strength (or tendency to increase the true local stress over the nominal) because of inclusions, which probably have a more injurious effect in hard heat-treated steels, such as must be used when great strength is sought, than in softer steels. Users of steel who make transverse tests find surprisingly low ductility on transverse bars of dirty steel, though the longitudinal tests may be good. Bending tests, reverse bending tests, and notch-bar impact tests,

Jan 1, 1923

By H. W. Gillett

Many of the parts of motor cars, aircraft, etc., that require strong light construction, hence must be made of high-quality steel, are stressed to the maximum limit only in a very small volume. In parts subject to bending stress a line or even a point may take the maximum stress. A series of endurance tests under repeated bending in progress in the U. S. Bureau of Mines laboratories, like similar tests by other investigators, has shown the great difference in life of sister bars of the same stecl, handled in the same way and tested at the same nominal stress. It is known that a surface notch or scratch greatly increases the local stress over the nominal calculated stress; internal notches, such as those formed by inclusions or sonims, probably have a similar effect. From the tetss made by the Bureau of Mines, the cleanliness of the steel at the dangerous section, or point of maximum stress, seems to be one of the most important factors in determining the life of the piece. The more localized the stress, the more does chance, rather than the average properties, dctermine the life of the steel. The usual test, a tension test of a bar taken longitudinally, is not sensitive to the local drop in strength (or tendency to increase the true local stress over the nominal) because of inclusions, which probably have a more injurious effect in hard heat-treated steels, such as must be used when great strength is sought, than in softer steels. Users of steel who make transverse tests find surprisingly low ductility on transverse bars of dirty steel, though the longitudinal tests may be good. Bending tests, reverse bending tests, and notch-bar impact tests,

Jan 1, 1923

By Fred H. Kan

The production of petroleum in Venezuela during 1931 was approximately 118,767,000 bbl., a decrease of 18,904,000 bbl., or 13.7 per cent, compared with the previous year. This is the first break in production, which has risen steadily since 1920, and is attributable to restriction of output and drilling operations, in harmony with lessened demand, rather than to any real decline in potential production. Venezuela ranked third among the world's producers, having lost second place to Russia. The Bolivar coastal fields, which were extended approximately 14 miles southward during the year, continued to supply most of the oil. La Concepcion, Los Manueles and Quiriquire all showed marked increases. A new field of light oil was discovered on the north coast near Puerto Cumarebo, State of Falcon. Exports declined 15.7 per cent, from 137,377,000 bbl. in 1930 to about 115,800,000 bbl. in 1931. Crude oil in storage at the end of the year amounted to 7,450,000 bbl., a decrease of 2,150,000 as compared with 1930. Tankage utilized is about 40 per cent of the available space. A drastic decline in drilling activity reduced the number of wells completed in producing areas from 401 in 1930 to 116 in 1931. Only three wells were drilled in the Lagunillas field proper, but, the amount of closed-in production and proven acreage gave assurance of a satisfactory potential output. Of the 1580 wells drilled to the close of 1931 in the producing areas of the Bolivar Coast, 631 were active and 853 were closed in; 96 had been abandoned. The status of the active wells at the end of 1931 was as follows: flowing, 331; pumping, 99; gas-air lift, 201. Producing wells closed in numbered 452; workovers, 8; totally inactive, 393. Lago Petroleum Corp. and Venezuela Gulf Oil Co. placed in operation the first units of their electric power plants, the former at Punta Gorda and the latter at Las Morochas, and are replacing steam power in their operations as rapidly as possible. Compressor stations were also installed for use in connection with air-gas lift operations. A considerable volume of gas was treated in gasoline extraction plants, the tail gas being recom-pressed and utilized together with natural high-pressure gas, for stimulation of production.

Jan 1, 1932

By F. Milton Lewis, Roshan B. Bhappu

In Part I of this article, published in the September issue of MINING ENGINEERING, Edward S. Frohling and Robert M. McGeorge of Mountain States Mineral Enterprises, Inc., reviewed the general overall financial aspects and methods of raising the necessary capital for developing the mine. In Part 2 of this two-article series, we will present several case histories to show how realistic feasibility studies are used for evaluating the choices and options entailed in mining ventures. Basically, after a potential ore body has been discovered, and the necessary funds obtained for the development of the deposit, the next major problem is one of ascertaining what specifically is to be produced, and the costs of production. The profit potential of the mining venture can then be accurately assessed by the mine owner, operator, or loan officer.

Jan 10, 1975

By Albert Roberts

Summary In response to a growing intolerance towards ground vibrations and noise as environmental pollutants the engineer must consider the effects of his operations as they are likely to be judged subjectively by the public at large. Much work has been done on the study of vibration damage to structures, but the damage criteria normally applied do not take into account any resonance effects, nor do they embody any subjective criterion. Mu1tiple criterion techniques of subjective appraisal have proven to be of value .in the assessment of environmental comfort in relation to ventilation, air conditioning, and lighting. One such scale, the Reiher-Meister Scale, has also been applied to ground vibrations and noise, and an attempt has been made to correlate this scale with objective criteria, using the parameters of frequency and displacement. This paper quotes examples and compares ground vibrations resulting from blasting, the operation of, vibrating and impact-hamner pi1e drivers, forge hammers, and railway and road traffic. The Reiher- Meister Scale was applied to a subjective-objective correlation in relation to vibrations from railway traffic and gave results which did not conflict with experience.

Jan 1, 1971

By M. I. Sherman, J. D. H. Strickland

PRELIMINARY experiments in these laboratories showed that whereas pyrite1 produced only sul-fate the action of aqueous chlorine solutions on most other sulfide ores resulted in the formation of a mixture of sulfate and elemental sulfur, the production of the latter being favored by a very dilute solution of oxidant. The reactions taking place were obviously complex and only a detailed kinetic study could be expected to clarify the position and enable a prediction to be made of conditions leading to the rapid formation of metal salt and the economically desirable elemental form of sulfur. Galena was chosen for the first investigation as it is of widespread occurrence and is representative of a simple cubic lattice sulfide containing the monosulfide unit, S2-. Experimental Procedure The apparatus and general technique used in this work have already been described.' Analyses for chlorine and sulfate were carried out by the same methods as those used for pyrite. The lead in 1 ml aliquots of solution was determined polarographi-cally, after destroying chlorine with hydrazine hy-drochloride and making solutions 0.5 molar with hydrochloric acid. A large sample of Kansas galena, assaying at better than 98 pet PbS, was crushed and wet sieved to give fractions of —10 + 14, —20 + 28, —28 + 35, and —48 + 65 Tyler screen. The particles were almost perfect cubes and the apparent surface Per gram was calculated assuming each particle a cube Of side equal to the mean mesh opening. A volume shape factor, calculated as for pyrite, was exactly unity. The main apparatus was unsuitable for direct visual examination of the ore particles during the reaction. For this purpose a small cell from a Spekker Absorptiometer optical flats 1 cm apart) was l by a greased microscope slide after filling with oxidant solution. One or two ore particles were placed in the cell and the solution was stirred by a glass covered speck of iron wire activated by an external rotating magnet. The surface of an ore particle was examined under a binocular microscope at between 10 and 40 magnifications. Results Experiments were made under a wide variety of conditions, the form of presentation of the data being illustrated by Fig. 1, where the concentrations of chlorine, sulfate, and sulfur are plotted against time. The fictitious concentration of solid sulfur is used for convenience and is the molarity of sulfur which would be recorded if the elementary sulfur formed during the reaction were dissolved in the liquid iii the reaction vessel. As some lead sulfate is occluded with the sulfur on the ore particles the amounts of sulfur and sulfate formed during a reaction cannot be calculated

Jan 1, 1958

By C Gunther

Many definitions have been advanced and many limitations advocated in the use of the terms, veins, lodes and ledges. The following definitions appear to follow the best usage. A fissure vein, according to Lindgren, is a mineral mass tabular in form as a whole, though often irregular in detail, filling or accompanying a fracture or series of closely set and intimately related parallel fractures in the enclosing rock, the mineral mass having been formed later than both the country rock and the

Jan 1, 1932

By L. P. Teas

The main facts brought out by the study of the blende-bearing ores examined are as follows: 1. Chalcopyrite as minute triangular or rectangular dots, or as

Jan 1, 1918