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By R. E. Kennedy

The presence in air of combustible cases and vapors can constitute an extremely serious explosion hazard. This hazard is even greater when explosive mixtures are confined under high pressures, as the pressure can become tremendous immediately before the container is ruptured. Because of its interest in safety in mining and allied industries, the Federal Bureau of Mines has investigated the flammability (explosibility) of various types of combustible atmospheres and has published Its findings. 4/ The explosibility of ethane has been studied, and its limits of flammability have been determined and published. The development of secondary recovery methods of stimulating oil production has intensified interest in the effect of high pressure on the explosibility of natural gas-air mixtures. The limits of flammability of natural gas-air mixtures at pressures ranging from 50 mm. Hg to 350 p.s.i.a. have been determined and published. More recently, the limits have been determined at pressures up to 3,00C p.s.i. in mixtures of natural gas-air-nitrogen.

Jan 1, 1950

By Neal M. Muir

The increasing demand for iron ores prompted the Bureau of Mines to investigate the sources of past production in Kentucky to determine whether reserves of usable ore still exist. Preliminary investigation showed that the holdings of the Rose Run Co. were the most promising, inasmuch as the deposit had not been exhausted by past mining and the property was near railroad facilities and but 80 miles from the blast furnaces at Ashland, Ky. The Bureau conducted a churn-drilling and sampling program to investigate the depth, thickness, and iron content of the ore beds so that they might be evaluated as a possible reserve of low-grade iron ores. The Rose Run area in Bath County, Ky., was explored by 74 churn-drill holes totaling 2,059.4 feet of drilling and 4 cuts and test pits. Fifty-seven drill holes and the four test pits penetrated the ore bed at an average depth of 22 feet. The bed had an average thickness of 2.54 feet. Analyses show that the calcium and magnesium carbonate content is more than sufficient to flux the silica and provides an excess that needs an admixture with other siliceous iron ores.

Jan 1, 1950

By Paul Averitt

The U. S. Geological Survey has been actively engaged in work on coal for more than 50 years. During this long period we have released more than 300 publications containing information about coal and coal reserves, including details on the thickness, distribution, and quality of coal, and the structure and stratigraphy of the coal-bearing rocks. We have also cooperated with state surveys on many similar publications. For many areas these reports are the only reliable published data on our resources of coal. During the last several years we have substantially increased our activities above the wartime low. We now have field work in progress, or reports in preparation, on 13 detailed mapping projects distributed as follows: 1. Pennsylvania anthracite field 2. Casselman Basin, Md. 3. Leslie County, Ky. 4. Deep River field, N. C. 5. Coosa field, Ala. 6. Powder River field, Mont. 7. Spotted Horse field, Wyo. 8. Yampa field, Colo. 9. Paonia field, Colo. 10. Trinidad field, Colo. 11. Durango field, Colo. 12. Chaco River area, N. M. 13. Lewis and Thurston County fields, Wash. For two of these areas; the Paonia field, Colo., and the Coosa field, Ala., we have published recently preliminary reports, and final reports are in preparation. In addition, we are nearing completion of a coal reserve study of Montana, and are beginning similar studies in several other states, as part of a program of revising our estimate of national coal resources on the basis of presently available data. Factors Involved in Making Estimates Our responsibilities include detailed field mapping to secure information on areas of outcrop of coal beds, their range in thickness, nature of roof rock, amount of overburden, correlation of the beds, stratigraphy and structure of the coal-bearing rocks, and the preparation of coal reserve figures based on these data. The computation and estimation of resources of coal in the ground, like that of resources of other mineral commodities, involves consideration of many additional purely geological factors that can be appraised best through such regional studies. Regional variations in the thickness and texture of rocks overlying and underlying coal beds, for example, give evidence as to the probable position of the edges of the basin of coal deposition, or may aid in the delineation of sand-filled channels that sometimes cut out coal beds. It is apparent that the detailed field studies, in which data are gathered, are the basis for coal reserve studies, and in our present program these two phases of work are being carried on together. Previous Coal Reserve Estimates For many years we have been aware

Jan 1, 1950

By R. C. Craze

During the past 20 years. research and development in the study of reservoir behavior have dealt principally with flow of oil through sandstones. Many reservoir studies of sand fields have proved valuable in promoting recovery efficiency. This paper discusses fundamental principles governing oil and gas production from sandstone and limestone alike and presents the results of investigations relating to the application of analytical techniques used for sandstone reservoir studies to the study of limestone reservoir performance. The characteristics of limestone porous systems, porosity-permeability relationships, distribution and occurrence of oil, and characteristics of flow through such systems are discussed. Recognition is made of the similarities or differences which these factors exhibit in limestone and sandstone systems. Comparisons between operating data for typical limestone and sand reservoirs are presented. It is indicated that the distribution and movement of fluids in and through porous limestones follow the same fundamental principles underlying such processes in sandstones. This fundamental similarity may readily be discernible in the performance of many limestone reservoirs. The volumetric balance and unsteady state radial flow equation, the fluid displacement equation, use of electrical analogue devices, and other analytical techniques to study the behavior of limestone fields appear fundamentally applicable, but do require thorough understanding of the properties of the formation, of the fluids, their behavior during flow, and adequate production operating data. Need for more complete coring and comprehensive examination of core properties is stressed. The results of "active oil" studies, and of flow and interference tests are presented. Well spacing, well completion, and efficient rates of production in limestone reservoirs are briefly discussed. INTRODUCTION Limestone and dolomite reservoirs constitute the largest source of supply of crude oil in the world. an estimated 60 per cent of present production coming from carbonate reservoirs. In many large geologic provinces such as Mexico. the Middle East, and more recently Canada, almost all the oil is found in this type of rock. In the United States, all of the major oil-producing areas except California and Pennsylvania contain oil-bearing carbonate formations. The discovery in recent years of large oil reserves in the Silurian, Devonian, and Ordo-vician formations in West Texas, in addition to the large reserves in the Permian, has accentuated the interest of operators, geologists, and engineers in limestone formations and in the many problems associated with understanding the performance of these reservoirs. The rapid increase in discovery of oil in limestone formations and the present-day position of prominence held by these fields in the production and reserve picture in all parts of the world emphasize the horizons opened to the reservoir technologist in the field of geological and production research. Pertinent to an interpretation of the behavior of limestone reservoirs are the methods of analysis which may be utilized and a possession of full knowledge of the many factors which influence the analytical procedures. During the past 20 years a well-developed science of reservoir engineering has been built upon the research of many workers who studied the fundamental nature of oil reservoirs, characteristics of the porous media, properties and behavior of the contained fluids, and the mechanics of flow. Application of these studies to production practice has resulted in greater recoveries and more efficient field operation. The major portion of this evolutionary process has been founded upon studies of sand fields. The applicability of these more thoroughly developed techniques for studying sand fields to the study of the behavior of limestone fields becomes a factor of technical and practical significance. In the light of the technological background available to the reservoir analyst, this paper discusses fundamental principles governing oil and gas production from sandstone and limestone alike and presents the results of investigations relating to the application of analytical techniques used for sandstone studies to the study of limestone reservoir performance. LIMESTONE RESERVOIR CHARACTERISTICS The characteristics of limestone and sandstone reservoirs are similar in many respects and they both may occur under similar structural conditions. Fundamentally, the distribution and movement of fluids in and through the porous limestone media follow the same basic principles which dictate such processes in sandstones. Herein lies a fundamental similarity, which may readily be discernible in the performance of many limestone reservoirs. In some limestone fields, as in many sand fields, widely varying formation properties and distribution may reveal themselves in deviations in the performance of the reservoir, in the behavior of wells, and in fluid flow through the rock, and make difficult the delineation of reservoir behavior. Only by reservoir studies, core analyses, and coordinated laboratory and field experimentation can the effects of the many influencing factors upon the nature of limestone production be determined. FORMATION CHARACTERISTICS The chief difference between limestone and sandstone, aside from their chemical compositions, is the difference in the geometry and origin of the porous systems in the two kinds of rock. In sandstone the porous system results entirely from the openings among individual sand grains which occur during deposition. The geometry of the openings between the sand

Jan 1, 1950

By Kenneth M. Earl

In its program of investigation of deposits of strategic minerals, the Bureau of Mines did some development drilling at the Douglas Deposit in an attempt to find an additional source of supply of copper. The deposit, which was opened in 1878, was worked until 1883 and is reported to have produced between 2 and 3 million pounds of copper. Heap-roasting and smelting and later gravity concentration were employed in ore reduction. Old slag dumps and tailing piles from these operations still remain. In 1917, the American Smelting & Refining Co., purchased the mine, and in June 1918 production was started in a 125-ton mill, using both tables and flotation. The mill was closed December 31, 1918, and soon after the milling plant Was dismantled and removed. The mine has remained idle ever since. The deposit occurs in a mineralized zone that follows the schistosity. The principal metallic minerals are pyrite) chalcopyrite, pyrrhotite) arsenopyrite, sphalerite, magnetite) slight chalcocitel and cuprite. To search for additional ore shoots and to prove the known ore shoot at depth, the Bureau of Mines drilled seven holes, which totaled 2,117.4 feet. No additional ore was developed by this work.

Jan 1, 1950

By The Staff

"SummaryDetermination of uranium in ores may be made by measurement of their radioactivity.The method most commonly used is that of measuring beta radiations with the tray-type beta counter. This will give an accurate uranium determination provided the sample does not contain thurium and that the beta and gamma activities have not been disturbed from their natural state of equilibrium. Such a loss of equilibrium will result from mining the ore or from the weathering of the surface rock.A method is described which eliminates errors due to loss of equilibrium. The beta and gamma activities are measured simultaneously in one simple operation. This method is recommended for assaying samples of products from milling operations and its use is limited only by the presence of thorium in a ratio greater than one part of thorium to twenty parts of uranium.A third method is recommended for the analysis of exploration samples and diamond drill cores, which may be assayed in the uncrushed state.Rapid determinations of a large number of samples is possible with the pressure ionization chamber, which is sensitive to gamma activity."

Jan 1, 1950

By Claude P. Heiner

W-hile the litle of this paper embraces the entire West Coast, the author, in the interest of simplification, has confined the discussion to California—particularly the central section. California's population has risen 45 pct since 1940. Its electric requirements have also increased, not only because of the growth in industry and population but also because of the widespread tendency of all types of electric consumers to use more electricity than ever before. The growth of California's electric utilities is shown by published data covering operations of three of its large systems and is given in Table 1. New Capacity Steam Driven In meeting these additional electric loads there has been a substantial increase in generation from fuel burning plants as shown by the published energy statistics given in Table 2. Increased Fuel Oil Consumption A study of construction plans of the three electric utility systems named in Table 2 clearly shows that expected new electric loads are to be met, to a large extent, by new steam generating capacity as shown by Table 3. D. D. Smalley, Vice President of the Pacific Gas and Electric Co., in an address before the Pacific Coast Electrical Association in June 1948, stated that California utilities plan to meet new electric loads through greater use of steal11 plank and that in 1951 approximately 45 pct of the area's electric production would be by steam as compared to 33.6 pct in 1946. He stated that if load growth develops as expected and if the year 1952 is dry, thereby requiring high load factor steam operation, the Pacific Gas and Electric Co. would need the equivalent of nearly 25 million barrels of fuel oil. Federal Power Commission reports show that the energy input to the Pacific Gas and Electric Co. system was approximately one billion kilowatt-hours greater in 1947 than in 1946. They also show that the steam plant operating capacity factor in 1946 was approximately 35 pct; in 1947 it, was 72 pct due, probably, to the extreme drought. able 3 shows that Pacific Gas and Electric Co. now has under construction 327,000 kw of hydro capacity which, by 1950, will bring its total hydro generating capacity to 1,313,899 kw. In addition to hydro capacity under construction that company also has 975,000 kw of steam generating capacity under construction, which by 1951 will bring its total steam capacity to 1,560,834 kw. If it is assumed that this total steam electric capacity is operated at a capacity factor of 45 pct, in 1951, over 6 billion kilowatt-hours would be generated. If the load growth on the Pacific Gas and Electric system continues at the current rate of approximately one billion kilowatt-hours per year and if it is assumed that 70 pct of this increase would be generated by steam (30 pct assumed to be generated by hydro facilities with average water conditions), the steam electric production in 1960 would amount to 12 billion kilowatt-hours, which would require fuel the equivalent of 24 million barrels of oil or 6 million tons of coal. Government Projects Inadequate Much has been written with respecl to the plans of the Department of Interior in regard to the installation of hydroelectric plants as a part of multipurpose dams relating to reclamation. flood control, and power generation. An examination of the effect of such plans on the power supply for central and northern California is of interest. The Depart,ment of Interior now has five 73,000 kw units at its Shasta hydro plant on the Sacramento River. It now appears that its three 25,000 kw unit Keswick hydro plant on the same river will be available during the winter of 1949 to 1950. Its estimates show that in a dry year there is sufficient water for operation of Shasta units at an average load factor of 36 pct and Keswick units at a load factor of 41 pct. It is also giving consideration to the development of the Pine Flat and Haas hydroelectric plants on Kings River for generating capacities of 45,000 kw each. The total installation of Government, units in Central Valley and Kings River in California is relat.ively small when compared with t.he

Jan 1, 1950

By C. F. Allen, G. B. Walker

The sink-float methods designated by heavy-media separation processes were pioneered by C. Erb Weunsch for the treatment of base metal ores as an improvement over jigs. The work of Weunsch was further developed by Victor Rakowsky and The American Zinc, Lead and Smelting Co. Early in the development of the processes, the inherent unsuitability of galena as the solid constituent of the medium was recognized and ferrous media amenable to magnetic recovery and control were developed. The high efficiency and low cost of magnetic recovery and cleaning of ferrous media regardless of particle size, slime contamination, or surfacial oxidation had led to the adoption of ferrous media by all of the sink-float plants operating under the heavy-media separation processes patents controlled by American Zinc, Lead and Smelting Co. Approximately 2,000,000 tons of base metal and nonmetallic minerals are treated each month by these methods. Heavy-media separation processes are a modern practical and economical adaptation of the well-known laboratory procedure for separating a mixture of two solids by immersing the mixture in a liquid having a specific gravity intermediate the specific gravities of two solids. The lighter solid floats while the heavier sinks. This method of separation has been attempted on a commercial scale, but the high loss and high cost of the organic liquids halted the development of the process. Many attempts have been made to simulate a heavy liquid by using a suspension of a finely divided solid in water. If the solid phase of the suspension is ground fine enough, the suspension can be made stable or so slow settling that a substantially uniform specific gravity can be maintained from top to bottom of the bath. However, any material separated by such methods will inevitably be contaminated by some slime which will eventually accumulate in the bath and cause a viscous medium at the expense of separating efficiency. Therefore, it is necessary to provide means for continually cleaning a portion of the medium to eliminate slime at the same rate at which it is introduced to the medium. The problem of efficiently cleaning the medium limits the minimum grain size of the solid of the suspension in the case of the Chance sand process for cleaning coal, because de-cantation is the only cleaning method available. If the sand is too fine, it will be lost along with the slime. Therefore, coarse sand must be used, and to maintain a semblance of a uniform suspension, it is necessary to use strong rising water currents. The combination results in a separation based more on hindered settling classification than on sink-float principles. As previously mentioned, galena was used as the solid constituent of the medium during the early stages of the development work. The high specific gravity of galena made it suitable for the preparation of medium for high specific gravity separations. Galena can be cleaned by either decantation or by froth flotation. As with sand, de-cantation limits the minimum particle size of the media that can be cleaned without excessive loss. Froth flotation for cleaning galena medium has been used, but the problem of floating fine galena that has been exposed to extensive oxidation is well known to be a most difficult one. Last year the largest heavy-media plant m the world, and the second plant to be installed, converted from galena medium to ferrous medium despite the fact that the ore contains galena which can be used as medium. The change to ferrous medium has been beneficial in many ways. Today all the heavy-media plants have been converted from galena to ferrous media. Unquestionably, ferrous media have the widest application of any media developed, for the following reasons: 1. Ease of recovery and cleaning by magnetic means. Particle size or surface condition not a factor. 2. Low consumption per ton of ore treated. 3. Resistance to abrasion. 4. Widest range of media densities, including higher workable densities (1.25 to 3.4) than have been found possible with nonferrous media. 5. Space required for recovery and cleaning of ferrous media is considerably less than that for nonferrous media. 6. Ferrous media require lower capital investment and operating costs for media recovery and cleaning. Advantages of Heavy-media Separation Processes Heavy-media separation processes offer the following positive advantages, amply demonstrated on a wide variety

Jan 1, 1950

By William L. Crentz

In a Nation-wide appraisal of coking-coal reserves and of the practicability of upgrading marginal deposits to metallurgical standards, this study of the preparation characteristics of the coals in Cambria County, Pa. , was undertaken. Over 90 percent of the coal remaining in Cambria Comity is found in the Upper Freeport, Lower Freeport, Upper Kittanning, and Lower Kittanning beds. The Middle Kittanning bed, although mined on a commercial scale in the past, is not an important bed now, as most of the remaining reserves are too thin to be mined over wide areas. For many years, Cambria County has been an important source of coal for industrial and metallurgical purposes. The) principal production comes from the Lower Kittanning bed, which accounts for almost .60 percent of the Cambria County coal output. Table 1 shows the county's coal production, by beds, during 1948.

Jan 1, 1950

The usefulness of laboratory studies - petrology and mineragraphy in the search for, and investigation of, mineral deposits should not be exaggerated, but it should not be overlooked, because such studies will always contribute to an understanding of the geology of the deposits, and can on occasions provide invaluable information not otherwise available. A few examples furnished by the investigations of the Mineragraphic Section of the Commonwealth Scientific and Industrial Research Organisation will show this.Petrology.In the early stages of the investigation of the King Island scheelite deposit, during the war, when the nature of, the deposit was not understood, a series of samples embodying the exposed rock types was submitted to the Mineragrap;hic Section for petrologicalexamination by the Mineral Resources Survey. It was at once apparent to the petrologist that the King Island scheelite ore was a contact metamorphic deposit, in which a series of argillaceous shales, calcareous shales, impure limestones and limestones had beenintensely metamorphosed. The shales had been converted to finegrained biotite and actinolite hornfels, according to their lime content, and the impure limestones to fine-grained diopside hornfels, garnetdiopside hornfels and garnet hornfels (calc-flint), the garnet being the lime variety grossularite. The limestones, however, after being first converted to marbles, had suffered intense pyrometasomatism, involving substitution of immense quantities ,of silica and' iron for lime and carbonate, and had been converted largely to a coarsegrained garnet rock, in which the garnet was the lime-iron variety, andradite. The silica and iron were derived from the mineralising solutions of the adja,cent ,granite. intrusion, responsible for the contact metamorphism, and were accompanied by tungsten and some molybdenum. The tungsten in the presence of so much mobile lime, was precipitated as schecelite, much of it finegrained and enclosed in or intergrown, with the andradite garnet or the quartz interstitial to the garnet.It was apparent that the King Island scheelite deposit, was a perfect example of selective pyrometallomatic replacement in a bedded contact metamorphic deposit. The bedded nature of the original rocks was preserved, and the scheelite was practically limited to the original limestone beds, 'Which had been so much more susceptible to replacement after recrystallization, than the other sediments. The further geological study of the deposit then resolved itself into the task of mapping the folding and faulting of the deposit, with bore cores to provide the stratigraphic sequence, and establish the number of scheelite-bearing beds.A second example is provided by a petrological investigation of the mineral composition and genesis of the talc deposits of the Gumeracha district of South Austral.ia, which was undertaken at the request of the South Australian ,Mines Department, in conjunctionwith mapping of these deposits. The field geologist mapping the deposits was experiencing some difficulty in interpreting the structure...

Jan 1, 1950

By Fred D. Gustafson

With the postwar emergency for new housing and for new industrial buildings, much research has been done on lightweight aggregates for use in concrete and plaster. The trend toward lighter weight aggregates to relieve the dead load on the higher, steel framework buildings started toward the end of the last century. Progressively the requirements became more stringent, crushed bank slag, weighing 80 lb per cu ft as compared to 100 lb for crushed rock, was supplemented in some sections by foamed slags and expanded shales weighing from 40 to 60 lb per cu ft. In other sections cinders were used weighing from 40 to 50 lb, including sand. Sections favored with more recent vulcanism turned to pumice weighing from 30 to 60 lb, whereas other localities made use of diatomite, from 28 to 40 lb. Exfoliated vermiculite weighing from only 6 to 10 lb per cu ft came into use. As the search for lighter weights in aggregates continued so did the search for other desirable properties such as nailability, ease of cutting or channeling, and good insulation to both sound and heat. This search eventually led to a widespread interest in the expansion of perlite, or similar volcanic glasses, with the result that in 1946, the Office of the Housing Expediter' listed eleven firms reporting the operation of processing plants either on pilot or commercial scale producing aggregates weighing from 2 to 16 lb per cu ft. Geology Perlite is one of the large family of rocks originating from a granitic or acidic magma and generally has a "rhyolitic composition with a marked perlitic structure."² The name "perlite" is a derivation from "perlstein" originally given "to certain glassy rocks (hyaloliparites, hyalo-rhyolites) with numerous concentric cracks, from the fancied resemblance of broken out fragments to pearls."3 The cause of the perlitic texture is somewhat controversial. Johannsen attributes the texture to strain set up in the glass by cooling and describes the finding of peculiar, glassy balls, called marekanite, more or less rounded and showing concave indentations, which may be left when perlite is broken. Frank Rutley, on the other hand, in 1881, while working on vitreous rocks from Montana, observed that there was incipient or partially started crystallization with segregation of water toward the un-crystallized portion in all specimens of perlite examined. Further he observed evidence of strain around focii of crystallization to which he ascribed the development of the spherical cracking which gives the rock its perlitic texture.4 Widespread over the western and southwestern United States where Tertiary vulcanism is exposed, perlite commonly is associated with andesitic, basaltic, and rhyolitic lavas with inter-bedded tuffs and ash of Eocene age although some deposits are associated with rocks assigned to the Pliocene age.5, 6 n nearly all cases the perlite overlies water laid tuff beds or agglomerates or breccias of explosive nature, an outstanding exception being the occurrence of perlite as the chilled selvage of andesite intrusions.7'8 Available chemical analyses of per-lites from the western and southwestern United States indicate that they are varieties of leucorhyolites rather than of normal rhyolites, leucorhyolites having less than 5 pct of dark minerals, normal rhyolites having more than 5 pct. This conforms with Johannsen's observation that leucorhyolites are the prevailing kind in North America.9 Tables 1 and 2 give

Jan 1, 1950

By W. Crafts, J. L. Lamont

Electrolytic extraction of carbides from quenched and tempered steel and their examination under the electron microscope were found to be helpful in understanding the mechanism of secondary hardening in alloy steels1 and the same technique has been applied to isothermally transformed steels. A preliminary survey of the utility of the method has indicated that it has promising possibilities for investigating the characteristics of pearlite and bainite. The examination of a few carbon and chromium steels has suggested that pearlite is formed with carbides of two varieties representing the lamellar and nonlamellar forms and that bainite appears to form with a structure analogous to, but significantly different from, martensite. Procedure The method used for examining the carbides was similar to that described previously.1 The chromium steels used in the investigation were made from an Armco iron base in an induction furnace and were not treated with grain-refining deoxidizers. The composition of the steels is given in Table 1. Three-inch square ingots were forged and rolled to 1/8-in. thick sheet for use in the isothermal studies. After rolling, the sheets were sandblasted to remove the rolling scale. Specimens approximately 3/4-in. wide and l1/2-in. long were prepared from the 1/8-in. sheet. They were heated in a salt "bath at 2100°F (1150°C) for 1/2 hour, transferred to other salt baths at 1300°F (704°C), 1000°F (538°C), 800°F (426°C), or 600°F (315°C), held for various periods up to 100 hr and finally quenched in water. After quenching, the specimens were cut in half, one half being submitted to microscopic examination and the other half being used for the electrolytic extraction. The isothermally transformed specimens were submitted to examination under the light microscope to determine the degree of transformation and type of structure and were photographed at 2000 X. Carbide residues were obtained by electrolyzing in 10 pet hydrochloric acid and collecting the residue in glycerine to minimize attack by the acid. As pointed out in the earlier paper, the carbides are attacked to some degree during electrolysis. This attack is relatively minor on the coarser carbides but may be quite severe on the fine bainitic carbides. The residues were washed free of the glycerine with water and alcohol. The alcohol was removed by repeated washings of amyl acetate, and the amyl acetate suspensions were transferred to stoppered vials. Debye-Sherrer X ray diffraction patterns of the residues were prepared using a chromium target. A selection based on the microstructure and X ray data was then made of samples considered most illustrative of the progress of transformation. Electrolytically extracted residues from these samples were submitted to examination by W. D. Forgeng and A. C. Jenkins on the electron microscope at the Research Laboratories of The Linde Air Products Co. and electron micrographs were made at X 5000 and enlarged to 25,000 X. The micrographs obtained with both the light and the electron microscopes are mounted side by side in the accompanying figures. Although no effort was made to establish the T-T-T diagram for the chromium steels, the times for holding in the salt bath were adjusted with the intention of making the samples represent different stages in the transformation at temperatures of 600, 800, 1000, and 1300°F. The degrees of transformation and results of X ray examination are shown in Tables 2—4. The carbide designations refer to orthorhombic or trigonal carbide types and are not meant to imply that the compositions are exactly as indicated. X ray Diffraction Data The occurrence of Fe3C and Cr7C3 in these steels was found to be consistent with published data on comparable chromium steels. Steels A and B with relatively low ratios of carbon to chromium contained Cr7C3 in the pearlitic structures and FeuC in the

Jan 1, 1950

By A. J. May

THE Star shaft is near the north boundary of the group of mining claims belonging to the Ground Hog Unit of the American Smelting and Refining Co., near Vanadium, N. Mex. The shaft bins and surface plant are served by a siding from the Atchison, Topeka and Santa Fe railroad, and this factor of railroad transportation influenced the choice of site. This paper describes the shaft sinking only, and does not cover the surface plant or other parts of the mine or its equipment. Experience with this shaft seems of interest because of the mechanical mucking, good rate of progress, and the costs obtained at the present level of labor and material costs. The shaft has four compartments, as shown in fig. 1. Equipment: Riddell Mucker: The mucking was done by a clamshell bucket and a Riddell mucker, which, as in other shafts sunk with this machine, consisted of a carriage mounted on axles with double flanged wheels that traveled back and forth on a swinging track, parallel to the long axis of the shaft (fig. 2 to 6). Three air motors were mounted on the carriage; one hoisted the clam, one operated the bucket opening and closing device, and the third moved the carriage along the track. The carriage was designed with guide shoes and could be hoisted to the surface in either skip compartment without trouble (fig. 4). During blasting operations the clam was tied on the rails and the carriage was hoisted up a few sets to protect it from flying rock. No attempt was made to hoist the carriage and clam together lest the clam catch in the timbers. The track on which the carriage operated was built of extra heavy 6 in. pipe with 1x2 in. strap welded on top for rails. A 1/2x4 in. angle was welded on the bottom of the 6 in. pipe with a 1 in. round rod welded in the angle for a filler and additional strength. The end or cross pieces of the track which kept the track to gauge, were also made of reinforced, heavy 6 in. pipe and were bolted to the long members on which the carriage traveled (fig. 2 and 3). This section of track was used, instead of heavy railroad rails, for two reasons: (1) this section would bend before it snapped and was much safer for the men in the bottom; and (2) it was a better blasting shield, and protected the timbers better, in fact, only five wall plates were broken by blasting in 1926 ft of shaft, although 150 to 225 lb of 40 pct powder was loaded per round, depending on the ground conditions. The swinging track was supported by four 5/s in. hoisting cables anchored to the end plates. There were also four safety cables fastened two to three sets above the carriage, which would catch the carriage if one of the supporting cables should fail for any reason (fig. 7). Clamshell Buckets: Two clams were used, each of 3/s yard capacity, both manufactured by Blaw Knox, Nos. 662 and 663. The No. 663 clam was 4 in. wider and 5 in. shorter than the No. 662, but seemed to dig and load more satisfactorily. It was easier to hoist and lower when it came up for repair. It did not turn over as easily, had less spill

Jan 1, 1950

By The Staff

"IntroductionThe published information concerning treatment of uranium ores has been very limited as far as Canadian ores are concerned. Such information has dealt mainly with refining processes for concentrates or rich ores, designed to recover radium rather than uranium; these methods could not be economically applied to low-grade ores.The purpose of this paper is to describe treatment possibilities for some of the .ores that have been treated at the Mines Branch, and .to show how the character of these ores influences methods and results.What is a Uranium Ore?Prospecting for uranium has been extremely active during the past two years and a great many occurrences of radioactive minerals have been recorded. Such prospecting has been based to a large extent on the use of the Geiger counter in the fie1d. This equipment is an invaluable aid when the results are properly interpreted.Most definitely, indications of high radioactivity do not always prove the presence of a valuable orebody. First we have to determine:(1) Is the radioactivity due to uranium or to thorium. There is no immediate market for thorium.(2) Can the uranium in the ore be economically recovered.Chemical analysis is the most exact method of determining uranium content, but a fair estimate of the uranium, and also of the thorium, content can be made from the difference in gamma and beta activity. The Mines Branch guards against misinterpretation by determining both beta and gamma activities and, if more than a minor amount of thorium is indicated, then a Chemical analysis is made."

Jan 1, 1950

By A. F. Brock

Introduction During the past ten years, shaft sinking has been going on continuously at Inco and new shafts and shaft extensions have been sunk under a broad diversity of conditions. The Murray mine and the Stobie section of the Frood-Stobie mine have?been opened and a main hoisting and supply shaft has been sunk at each of these mines; No. 2 shaft at Murray was sunk initially from surface to 1,960 feet and is now being extended; No. 7 shaft at Stobie was sunk from surface to 3,105 feet. No. 2 shaft at Garson has been extended from 2,200 feet to 3,200 feet in depth. At Levack, No. 2 shaft is being extended from 1,860 feet to 2,850 feet for ore hoisting from the 2,650 lev el. At Creighton, No. 6 shaft, collared on 52 level, was sunk 1,740 feet to a total depth of 5,563 feet below surface. It is the deepest Inco working. At Creighton, also, No. 7 shaft is being sunk from surface to the 30 level to handle the ore from caving operations. Ail Inco main hoisting and supply shafts sunk during the past twenty years have been vertical rectangular shafts equipped with two cages and two ore skips. The cages are standard and interchangeable for all shafts except Garson No. 2; they are single-deck, 13 ft. 4 in. by 5 ft. 2 in. inside and are designed to carry a maximum material load of 16,000 lb. The man load is 48 men. Skip capacities at the several shafts vary from 8 to 15 tons. Forty-two hundred feet bas been established as the standard vertical lift, and the permanent hoisting equipment at each shaft is designed for eventual hoisting from that depth.

Jan 1, 1950

By R. H. Swallow, George Hess

The purpose of presenting this paper is to show: 1. The applications of aerial photography to the map requirements of strip mining. 2. The methods and procedures for producing accurate aerial contour maps. 3. The advantages of aerial contour mapping over stadia or plane table methods. Introduction Aerial photography was once a crude, uncertain tool. 'Today it is a precision mapping instrument which saves important time and money for strip mining and other industry. Aerial photography began in the boxkite days of aviation. The Army first used it for rough reconnaissance photographs. Then, in the early Twenties, industry began to use aerial photographs of their plants and facilities for advertising or annual reports. The quality of these pictures was not very good by today's standards, but this work began the development of better cameras, better lenses, better photographic techniques. Then, some farsighted engineers and aerial photographers found that if the camera's axis were vertical to the earth's surface, these pictures could be the source of valuable mapping information. By viewing these pictures in stereoscopic pairs, accurate measurements could be made and contour maps produced from this aerial photographic base. So the aerial mapping business developed, using the plane and aerial camera to collect the data, working with skilled ground parties who established a network of ground control for this map information photographed from the air. Over the following years, a whole new science developed, known as photogrammetry. Precision cameras and lenses were perfected, and the narrow view of the surveyor's transit was broadened to the vast perspective of the mapping plane. Stereoscopic Coverage Obtained Today in making aerial topographic maps, aerial photographs are exposed so that full stereoscopic coverage for the survey area is secured. To obtain true elevations these photographs are processed through a series of precision measuring and contouring instruments which employ a principle similar to the military range finder. Here is how aerial mapping is being used by your industry. Topographic maps are but one of three products from aerial photographic surveys. First, there are the individual photographs. These are taken in flight strips, exposed with an overlap, just as shingle on a roof overlap. Exposures are overlapped from 55 to 60 pct along the line of flight so that a large part of the area in one picture also appears on the adjacent photograph. Successive strips are flown with a side-lap of between 20 and 25 pct. Each point on the ground thus will be somewhere near the center of at least one photograph in the series. They may be studied under a stereoscope and relief seen in a third dimensional effect. Geologic features that may go unobserved in ground exploration are often detected under stereoscopic inspection. Moreover, though field checking is not obviated with these aerial photographs, it is directed toward critical areas and toward worthwhile anomalies. Aerial Photographic Mosaics The second product of an aerial survey is the photographic mosaic. This is an assembly of carefully matched aerial photographs in mosaic form. Although not as accurate as the topographic map, it does reveal a wealth of cultural detail in true relative scale. Since the mapping plane is flown over the area at a fixed altitude, the peaks and valleys are pictured at different scales. During compilation these scale differences are compensated by adjusting one vertical picture to another according to plotted ground control positions. Only extreme variations in ground elevation cannot be

Jan 1, 1950

By Paul H. Price, John P. Nolting

The history of the salt industry in West Virginia dates back nearly two hundred years; howTever, the history of salt as an important raw material for the chemical industry is much more recent. The earliest record of West Virginia salt was in 1753, when a raiding party of Shawnee Indians attacked frontier settlements in Virginia taking captive a number of the pioneers. One of these, who later escaped and returned to her friends, described how the Indians camped at a salt spring on the banks of the Kanawha River and evaporated the water to obtain a supply of salt to take back to Ohio with them. Settlement of the Kanawha Valley began in 1774, that same year the Battle of Point Pleasant ended the Indian's power in the Ohio Valley; and settlement of the Kanawha Valley progressed rapidly with a consequent increase in the importance of the Kanawha Licks as a source of salt. In those days the evaporation of the brine was a family matter for which the family wash-kettle was commandeered. In 1797, Elisha Brooks erected the first salt furnace in the Kanawha Valley. It consisted of two dozen small kettles set in a double row, with a flue beneath, a chimney at one end, and a fire bed at the other. He obtained his brine at a depth of 20 to 30 ft by sinking hollow logs, called "gums" into the salt lick and dipping the brine with a bucket. His production was about 150 lb a day and sold for 8 to 10 cents a pound. In 1806, the Ruffner brothers, David and Joseph, prospected for and drilled the first well in America using a spring pole and steel chisel bit. After several failures they succeeded, in 1808, in drilling to a total depth of 59 ft where they secured a good flow of strong brine. Most standard drilling tools, jars, casing, and practically all the basic oil well drilling machinery now in use, were developed in the drilling of salt wells. To evaporate this brine, the brothers built a wood-burning furnace similar to that of Brooks but with a better arrangement and with more and larger kettles. When production was started they reduced the price of salt to 4 cents a pound. By 1817, there were some 30 salt furnaces in the Kanawha area. It was in this year that bituminous coal first was used as an industrial fuel. David Ruffner again pioneered the way by converting his furnace for the consumption of coal. This year also brought about the formation of the first trust which controlled production and set a price of 1 cent a pound for the salt.

Jan 1, 1950

By F. R. Erick Mulder

"AbstractTwo bottom-hole samples have been taken from two new completions in the Turner Valley field, Royalite Lowery No. 8 on the west flank and Royalite No. 73, which was deepened into a lower fault block, on the northeast flank. From the bottom-hole oil of Royalite Lowary No. 8 a synthetic sample was prepared to simulate the original fluid in the reservoir, saturated at the gas-oil contact conditions. The sample from Royalite Lewery No. 8 has been shown to be the original fluid present at this well and represents the oil phase near the oil-water contact in• the reservoir. Complete chemical analysis, P.V.T., and viscosity data have been obtained on these reservoir fluids, which represent the range of saturation from the gas-oil to the oil-water contact in the Turner Valley oil structures. Sampling techniques and the application of the analytical data to reservoir conditions and field operations are discussed. Super-compressibility curves for an average separator tail gas have also been prepared. These data have not been available before. They will be of fundamental value in futu.re reservoir engineering studies of this field and will also serve as a guide in determining operating practices."

Jan 1, 1950

Jan 1, 1950

Contents.SummaryIntroductionSituation, climate, topographyHistorySize of depositsPrevious investigationsGeological History of AreaMap compilationHistorical summaryNature and Significance of Granitic RocksSynchronous granitesMain subsequent granitesSignificance of types of bathylithsGeological StructureNorth-south anticlineCross-foldingFormation of channelwaysHydrothermal Depth-Zoning at CobarAssociation of Ores with PorphyryOrigin of replacement porphyriesTransgressive porphyriesSummary of ore-porphyry relationshipsSource of the Copper and GoldProspecting Targets, Cobar-NymageeGeneral ApplicationBroken HillThe Bendigo FieldKalgoorlie-Coolgardie, Western AustraliaConclusions

Jan 1, 1950