Search Documents

The world's production of petroleum in 1926 amounted to nearly 150 million long tons, of which India contributed 0.72 per cent. In 1927, this figure jumped to some 172 million long tons, of which the Indian proportion, on a practically stationary production, fell to 0.64 per cent. In 1928, there was another substantial rise in the world's production, which reached the figure of over 181 million tons. In 1929, there was another jump to over 202 million tons, but in 1930 the world's production fell to about 193% million tons, in 1931 to about 187 million tons, and in 1932 to about 183 million tons, while in 1933 the production rose again to about 202 million tons, in 1934 to about 215 million tons, and in 1935 to 233 million tons1. Decreases were shown by Poland, Sarawak, Egypt, Rumania and France. All other important producers showed an increase in production, by far the largest being due to Iraq, as a result of the opening of the pipe line to the Mediterranean. The United States contributed 60.9 per cent of the world's supply in 1935, Russia 10.7 per cent, Venezuela 9.4 per cent, Rumania 3.9 per cent and Iran 3.1 per cent. In 1928, India contributed 0.64 per cent, which fell to 0.60 per cent in 1929 and rose to 0.62 per cent in 1930, 0.63 per cent in 1931, and 0.64 per cent in 1932, and fell again to 0.62 per cent in 1933, to 0.60 per cent in 1934 and to 0.50 per cent in 1935; her position on the list of petroleum-producing countries fell from eleventh in 1929 to twelfth in 1930 to 1933, her place being taken by Trinidad and to thirteenth in 1934 and 1935, owing to the production by Iraq. The production of petroleum in India (including Burma2) increased slightly from 322,025,280 gal.3 in 1934 to 322,662,336 gal. in 1935, the highest figure in the history of the industry. The increase in 1935 is due to an increase of some 4 million gallons in Assam, almost offset by a decrease of 31/2 million gallons in Burma. This increase in output in 1935 was accompanied by an increase in estimated value amounting to Rs. 22,73,550 (£170,944).

Jan 1, 1937

By Herbert H. Kouns, Harlan W. Nelson, Bruce O. Buckland

GASIFICATION of coal under pressure produces a gas that may be used as the fuel in a gas turbine. The pressure produced by a gas-turbine compressor (5 to 9 atm) should allow the use of high firing rates without unreasonably high solid carry-over rates. Hot make-gas with the tars contained in it in the vapor form can be used in a gas turbine. Most of the ash can be removed through a grate, and only a small portion of the ash and any of the solid combustible material carried over by the make-gas requires separation. The gas stream from which separation is required is a small portion of the total flow of a gas-turbine plant and hence the separator size will be small. The gas stream is reducing and will not, therefore, allow separator fires to occur. The response of the producer to rapid load changes is satisfactory. Only the air rate must change substantially in synchronism with the load. The coal feed, the steam addition to the blast, and the ash-removal rate can follow the load changes with time lags in the order of minutes. The necessary control equipment is simplified by these producer characteristics. With these possibilities in mind, the Steam Turbine Division of the General Electric Co. made arrangements with Battelle Memorial Institute in January 1945 to investigate the problems of the gasification process. A number of tests were made during this investigation on an updraft producer with a grate area of 1 sq ft. The equipment used has been described and the results of the tests made between 1946 and 1950 have been reported.1 The testing with this small producer was recently completed. The concluding tests were run to determine the effectiveness of a clinker-grinding grate and the effect of the operating conditions on the amount and character of the solid carry-over. The present paper describes the producer as modified, and gives the results of the tests using three coals. Another method of using coal in gas turbines is to pulverize it and burn it directly in the combustion chambers. This plan is being tried by the Loco- motive Development Committee of the Bituminous Coal Research, Inc., whose investigation has reached the stage of tests of full-sized equipment.

Jan 1, 1953

By Robert H. Richards

(Read at the Wilkes-Barre Meeting, May. 1877.) THE Institute of Mining Engineers has shown so much interest in the educational problem of profitably combining theory and practice, that it seems especially appropriate to lay before its members the methods and aims of the mining laboratory of which I have charge, and in which one form of combination of hand with head work is now being tried. If anything may be contributed toward the solution of this problem by the discussion which follows, my purpose will be attained. Whether it was wise or not to establish a mining school so far from the principal mining centres, does not now enter into the question. Given, a mining school already begun, how shall it be made most efficient in developing engineers who are trained to think for themselves as well as versed in the works of others? This is the ques¬tion with which we have had to deal. In considering the bearing of this laboratory work upon the students' preparation, it will be convenient to take it up under five different heads 1. The methods and aims of the laboratory. 2. The advantage to students of having a part, at least, of their practical work in the curriculum of their school. 3. The advantage to be derived by mines and works. 4. Degree of accuracy which may be attained in working ores on a small scale. 5. Results of work in the laboratory. 1. The Methods and Aims of the Laboratory.-During the May meeting of 1873, held in Boston, I had the privilege of reading before you a paper stating the plans and aims of this laboratory. Since that time we have been constantly following out those plans, and are more than ever convinced that we are working in the right direction. We do not feel that the time we have spent has been in any sense thrown away. Perhaps the aims of the laboratory can be most clearly shown by illustration. Many young engineers leave school thinking that they know everything. They go to the works, and expect to teach the superintendent something and the men a good deal, regardless of the fact that it is this spirit that has prejudiced workmen against schoolmen. They are often more trouble than they

Jan 1, 1878

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

By Joseph E. Pogue, F. G. Coqueron

Prior to 1934, published information covering expenditures by oil companies for properties, plant, and equipment and the residual investments in the various segments of the petroleum industry was not readily available. This paper presents an analysis of the funds invested by a selected group of oil companies during the years 1934 through 1942, based on an extensive study of the individual records of 30 oil companies. The sources, disposition, and characteristics of the capital employed by this group of companies are traced through a series of combined statements and appropriate charts, covering financial and operating data. The analysis of these statements not only constitutes a record useful for comparative purposes but also serves as a basis for a number of broad conclusions, as follows: 1. The petroleum industry generates the capital needed for its expansion almost entirely from its own operations and is therefore a singularly self-contained economic unit. 2. The long-term debt contained in the financial structure of the industry is small relative to the total capital employed, is less than the net working capital, and has increased but slightly during the period under review. 3. The capital expenditures of the group of 30 oil companies for 9 years amounted to 6.1 billion dollars, 58.3 per cent of which went into crude-oil producing facilities. The trend of this segment of expenditures has been downward since 1937. In 1942, expenditures for refining facilities increased sharply and for marketing facilities declined drastically. 4. The net working capital of the group increased 380 million dollars over the period, and the industry is in a favorable position of liquidity. The ratio of combined current assets to current liabilities was 3.21 at the close of the period. 5. The net income of the group displayed an upward trend for the period but with rather sharp cyclical fluctuations. 6. In 1942, Government funds entered the industry for the first time in substantial amounts and were utilized for the provision of war facilities needed for emergency use. 7. The group has paid out a relatively low percentage of net income in the form of dividends. For the period the average was 55 per cent of net income. 8. The rate of return on invested capital for the group averaged 6.4 per cent for the

Jan 1, 1944

By Joseph E. Pogue, F. G. Coqueron

Prior to 1934, published information covering expenditures by oil companies for properties, plant, and equipment and the residual investments in the various segments of the petroleum industry was not readily available. This paper presents an analysis of the funds invested by a selected group of oil companies during the years 1934 through 1942, based on an extensive study of the individual records of 30 oil companies. The sources, disposition, and characteristics of the capital employed by this group of companies are traced through a series of combined statements and appropriate charts, covering financial and operating data. The analysis of these statements not only constitutes a record useful for comparative purposes but also serves as a basis for a number of broad conclusions, as follows: 1. The petroleum industry generates the capital needed for its expansion almost entirely from its own operations and is therefore a singularly self-contained economic unit. 2. The long-term debt contained in the financial structure of the industry is small relative to the total capital employed, is less than the net working capital, and has increased but slightly during the period under review. 3. The capital expenditures of the group of 30 oil companies for 9 years amounted to 6.1 billion dollars, 58.3 per cent of which went into crude-oil producing facilities. The trend of this segment of expenditures has been downward since 1937. In 1942, expenditures for refining facilities increased sharply and for marketing facilities declined drastically. 4. The net working capital of the group increased 380 million dollars over the period, and the industry is in a favorable position of liquidity. The ratio of combined current assets to current liabilities was 3.21 at the close of the period. 5. The net income of the group displayed an upward trend for the period but with rather sharp cyclical fluctuations. 6. In 1942, Government funds entered the industry for the first time in substantial amounts and were utilized for the provision of war facilities needed for emergency use. 7. The group has paid out a relatively low percentage of net income in the form of dividends. For the period the average was 55 per cent of net income. 8. The rate of return on invested capital for the group averaged 6.4 per cent for the

Jan 1, 1944

By G. Carman Ridland

Front Range, Colorado: The majority of the rocks comprising the Front Range of Colorado are pre-Cambrian schists, gneisses, and intrusives which have been elevated to form part of the Southern Rocky Mountain physiographic province. The region is noted mainly for its production of gold and silver, but ores of tungsten, fluorspar, uranium, copper, and iron have been worked. Geological literature1-' describes pitchblende and other radioactive minerals occurring at Jamestown, Boulder County; Central City, Gilpin County; and Lawson, Clear Creek County (fig. 1). These three adjoining G. CARMAN RIDLAND, Member AIME, is a Consulting Geological Engineer, New York, N. Y. San Francisco Meeting, February 1949. TP 2738 IL. Discussion of this paper (2 copies) may be sent to Transactions AIME before Feb. 28, 1950. Manuscript received March 30, 1949. counties cover most of the highly mineralized section of the Front Range which extends from Jamestown to Breckenridge. As far as the writer is aware, uranium has been found only in the portion northeast of Lawson. Silver Deposits at Caribou Hill: The historic silver deposits of Caribou Hill, located approximately half way between Jamestown and Central City, and 35 miles in a straight line northwest of Denver, appeared particularly intriguing as an area to prospect for uranium for the following reasons: here exists an isolated group of high-grade silver veins in the center of a mining district containing occurrences of uranium, and, in two of the well-known uranium deposits of the world, those at Great Bear Lake, Canada, and Joachimsthal, Czechoslovakia, uranium is associated with silver in similar fissure veins. An exploration program, conducted in the spring of 1945, directed special attention to Caribou Hill and was rewarded with the discovery of heavy, canary-yellow stained specimens of'pitchblende. The veins are confined to shear zones cutting a north-south, elongated quartz-monzonite stock of Tertiary (?) age lying in the axis of a major anticline of the Idaho Springs biotite schist, the oldest pre-Cambrian formation in the district. The stock is one and three-quarter miles long by more than a mile wide, and Caribou Hill is approximately at its center. The ore zones vary in width from a few inches to 15 ft, and one structure has been traced for a length of over 4000 ft. The ore minerals are galena, sphalerite, ruby silver, native silver, chalcopyrite, pyrite, and pitchblende. They occur most common-

Jan 1, 1951

The primary purpose of the Institute is to advance the technologic and engineering arts embraced by it through interchange of knowledge. This can best be clone by the presentation and discussion of technical papers by its members. Short practical papers are especially welcome. An author should always satisfy himself that his material is of a quality that will he a credit to him and to the Institute. The preparation of a good paper frequently leads to a reorientation of the author's thoughts, and publication contributes much to the professional standing of the author. Members are urged to submit papers presenting the results of their work. Attention to the following suggestions will greatly further the prompt and efficient handling of manuscripts. 1. SUBJECTS: The subject must be within the field of the Institute. Original work, the results of field, plant, laboratory or theoretical investigations, new views on old but important problems and occasionally reviews of timely and important subjects of wide interest to our members may constitute the basis of a paper. The mere fact that the work is original does not necessarily justify publication: it must be of a substantial nature, of value to a reasonable number of our members and worthy of permanent record. It is seldom desirable to subdivide the results of a single research for publication in a variety of journals. Previous publication is usually a bar to acceptance. If any part of your paper has been published elsewhere and you regard repetition as absolutely necessary please so state in your covering letter. 2. CONSTRUCTION: Papers should be clearly and concisely written in good English. Care in this regard ensures wider reading and the saving in space permits the Institute to publish more papers. It is the experience of the Papers and Publications Committee that most papers can he improved by condensation. "Readers" who are asked to recommend acceptance or nonacceptance put particular emphasis on the length of the paper and the elimination of unnecessary or any extraneous material. The terminology and units employed should be those current in the particular field. An examination of Institute publications will afford useful guidance in such matters. Webster's New International Dictionary, 1935 edition, is the Institute's authority for spelling and style. Various abbreviations are used habitually; for instance, lb., pound; bbl., barrel or barrels; ft., foot or feet; hr., hour or hours; in., inch or inches; Fig. 1 but Figs. 2 and 3.

Jan 1, 1946

By Lewis A. Riley

I desire to submit, for the consideration and information of the members of the Institute, the following data, drawings, and tables, showing what I believe will be interesting information with regard to the diamond drill, and its uses in developing mineral lands. I would first say that the results given have been obtained during the past two years by means of two drilling machines belonging to the Lehigh Valley Coal Company, operating on their coal lands in the Mahanoy, Lehigh, and Wyoming regions. 1st. A tabulated statement, giving location of borings, date, progress, total cost, itemized cost per foot, etc. 2d. Section showing strata bored in Nos. 5 and 10 holes at Mt. Carmel, see Plate VI. 3d. Section showing strata bored in No. 19 hole at Hazleton, see Plate VI. 4th. Photograph and description of drill No. 2. From the first it will be seen that the total number of test-holes bored up to May 1st of this year is 24; 9 of these are in the Mahanoy region, 6 in the Lehigh region, and 10 in the Wyoming region, in all of which cores have been taken for the whole distance. The total distance bored is 9902 feet. The majority of the holes have been put down for the purpose of proving the lower veins of the coal series, and have had to encounter the harder rocks of the coal formation. Much of the distance has been through the lower conglomerates, going in some cases through the coarse egg conglomerate, the foundation of the coal deposit, and to the green sandstone and red shale which underlie it. These lower sandrocks and conglomerates are among the hardest known to geologists, and present a formidable resistance to the exploring drill. This fact must be taken into consideratiotl in comparisons of cost of drilling, and when considered will still further improve the very favorable results I am able to show in my statement of costs. In illustration, I will cite the work of one bit when boring in the upper or softer rocks of the Wyoming region, where 280 feet were obtained without resetting, while in the Lehigh and Mahanoy regions, in the lower and harder rocks, bits set with the same quality of diamonds would only bore from 3 to 20 feet before being worn out. In this connection it may

By G. Carman Ridland

Front Range, Colorado: The majority of the rocks comprising the Front Range of Colorado are pre-Cambrian schists, gneisses, and intrusives which have been elevated to form part of the Southern Rocky Mountain physiographic province. The region is noted mainly for its production of gold and silver, but ores of tungsten, fluorspar, uranium, copper, and iron have been worked. Geological literature1-' describes pitchblende and other radioactive minerals occurring at Jamestown, Boulder County; Central City, Gilpin County; and Lawson, Clear Creek County (fig. 1). These three adjoining G. CARMAN RIDLAND, Member AIME, is a Consulting Geological Engineer, New York, N. Y. San Francisco Meeting, February 1949. TP 2738 IL. Discussion of this paper (2 copies) may be sent to Transactions AIME before Feb. 28, 1950. Manuscript received March 30, 1949. counties cover most of the highly mineralized section of the Front Range which extends from Jamestown to Breckenridge. As far as the writer is aware, uranium has been found only in the portion northeast of Lawson. Silver Deposits at Caribou Hill: The historic silver deposits of Caribou Hill, located approximately half way between Jamestown and Central City, and 35 miles in a straight line northwest of Denver, appeared particularly intriguing as an area to prospect for uranium for the following reasons: here exists an isolated group of high-grade silver veins in the center of a mining district containing occurrences of uranium, and, in two of the well-known uranium deposits of the world, those at Great Bear Lake, Canada, and Joachimsthal, Czechoslovakia, uranium is associated with silver in similar fissure veins. An exploration program, conducted in the spring of 1945, directed special attention to Caribou Hill and was rewarded with the discovery of heavy, canary-yellow stained specimens of'pitchblende. The veins are confined to shear zones cutting a north-south, elongated quartz-monzonite stock of Tertiary (?) age lying in the axis of a major anticline of the Idaho Springs biotite schist, the oldest pre-Cambrian formation in the district. The stock is one and three-quarter miles long by more than a mile wide, and Caribou Hill is approximately at its center. The ore zones vary in width from a few inches to 15 ft, and one structure has been traced for a length of over 4000 ft. The ore minerals are galena, sphalerite, ruby silver, native silver, chalcopyrite, pyrite, and pitchblende. They occur most common-

Jan 1, 1951

By D. G. Westlake, D. T. Peterson

The saturation solubility of thorium dihydride in thorium was studied by saturation of samples and subsequent analysis. The solubility increased from about 1 at. pct at 300°C to above 20 at. pct at 800 °C. Over this temperature range the log of the solubility was a linear function of the reciprocal absolute temperature for thorium of good purity. The heat of solution of thorium dihydride was found to be 7.9 kcal per atom of hydrogen in crystal bar thorium and 6.6 kcal per atom of hydrogen in Ames thorium, The important effect of hydrogen on the physical and mechanical properties of many metals is receiving increasing recognition. The basic physical and chemical data necessary to help explain the observed effects of hydrogen on the mechanical proper ties of metals are all too often not available. The solubility of hydrogen in thorium metal was determined to provide a portion of this basic data for the thorium-hydrogen system. The absorption of hydrogen by thorium metal and the formation of thorium hydrides was studied by several investigators, beginning in 1891, and their work is summarized in Gmelin's Handbuch.1 No effort was made to determine the extent of solid solubility in the metal in these early investigations and the impure metal available made interpretation of the results uncertain. Nottorf2 reported the results of a careful study of pressure-composition isotherms for the thorium-hydrogen system. The principal interest in this work was in the composition and dissociation pressures of the thorium hydrides. Mallett and campbel13 reported the pressure-composition isotherms for the thorium-hydrogen system up to the composition of thorium dihydride. The saturation solubility of thorium dihydride in thorium was reported to be 13 at. pct at 650°C and 23 at. pct at about 900° C. Mallett and Campbell used thorium metal which had been prepared by the calcium reduction of thorium tetra-fluoride or thorium oxide. The results obtained with thorium of these two types agreed within the experimental error. PROCEDURE AND MATERIALS Procedure—The method used to determine the solubility was to saturate a sample of thorium with hydrogen and analyze a portion of the saturated sample. This method was chosen rather than a determination of pressure-composition isotherms since it was much less time consuming and could be applied at temperatures at which the equilibrium hydrogen pressure was too low to measure. The

Jan 1, 1960

By W. P. Heineken, A. T. Child

This paper presents the results of a series of experiments made in the metallurgical laboratory of Columbia University, New Pork City. The object of the investigation was to determine, as far as possible, the changes in micro-structure and physical properties caused by short periods of heat-treatment and the longer malleable cast-iron process. It was proposed to do this by means of micro-photographs, heating- and cooling-curves, and tensile tests after the various heat-treatments. I. Micro-Constituents of Iron and Steel. The list of the micro-constituents of iron and steel has grown till now it includes seven different substances, called ferrite, cementite, pearlite,* martensite, austenite, sorbite and troosite. Only the first five of these are mentioned in this paper, to facilitate the understanding of which, the following brief definitions are given: 1. Ferrite (named by Prof. Howe) is, chemically, iron free from carbon. It is the softest of the constituents, and is not colored by etching, except when long-continued. Under the microscope it is easily determined by its regular polygonal etructure; or, if structureless, as in malleable cast-iron, by the ease with which it is scratched. Ferrite appears in mild steel in small amount, in grey cast-iron, and in malleable cast-iron. 2. Cementite (also named by Prof. Howe) is now generally conceded to have the formula Fe3C. It is the hardest of the micro-constituents, having the hardness indicated by 7 of the mineralogical scale; and hence it is always left in relief after

Jan 1, 1901

By C. A. Hartnagel, D. H. Newland

The market for Pennsylvania grade showed a drop both in demand and in prices, which reacted unfavorably on New York oil production, all of which comes under that classification. The output for the year in New York amounted to 5,045,200 bbl. The production in 1937 was 5,478,000 bbl., the largest in any year for the last half century or more. Falling prices, of course, affected new drilling. They declined from $2.20 a barrel, which was posted at the start, to $1.68 in the final months of 1938. With this came a reduction in the amount of oil that would be accepted by the refineries operating in the New York fields. Conditions therefore have combined to halt, at least temporarily, the growth of oil production in the state, which had experienced a steady gain for the last 15 years or more, the yield having risen from less than 1,000,000 bbl. to the round total of 5,500,000 bbl. in 1937. Practically all the oil now obtained is from old, developed fields. No new pools have been found in the last quarter of a century or more. The larger share comes from flooding the sands. Although there are many wells that still produce without the aid of the water drive, they are small and for the most part are pumped periodically. Of late, new drilling has been restricted mainly to that required to maintain existing flood projects. Because of the high initial cost and time required to put a flood into production, the depressed condition of the market has been a serious handicap financially, and, further, has been an unfavorable influence on the planning of operations to secure the maximum recovery of the oil. Unless market conditions improve, it is certain that the effects will be shown in the yield for some time to come. Gas Developments Drilling was active in the southwestern area, chiefly in Allegany and Steuben Counties, and some notable wells were brought in that tapped the Oriskany sandstone. Altogether 42 holes were put down in the two counties, of which 31 were listed as producers and 11 were dry. The new wells gave an initial daily flow of 239,000 M cu. ft. At the close of

Jan 1, 1939

By C. A. Hartnagel, D. H. Newland

The market for Pennsylvania grade showed a drop both in demand and in prices, which reacted unfavorably on New York oil production, all of which comes under that classification. The output for the year in New York amounted to 5,045,200 bbl. The production in 1937 was 5,478,000 bbl., the largest in any year for the last half century or more. Falling prices, of course, affected new drilling. They declined from $2.20 a barrel, which was posted at the start, to $1.68 in the final months of 1938. With this came a reduction in the amount of oil that would be accepted by the refineries operating in the New York fields. Conditions therefore have combined to halt, at least temporarily, the growth of oil production in the state, which had experienced a steady gain for the last 15 years or more, the yield having risen from less than 1,000,000 bbl. to the round total of 5,500,000 bbl. in 1937. Practically all the oil now obtained is from old, developed fields. No new pools have been found in the last quarter of a century or more. The larger share comes from flooding the sands. Although there are many wells that still produce without the aid of the water drive, they are small and for the most part are pumped periodically. Of late, new drilling has been restricted mainly to that required to maintain existing flood projects. Because of the high initial cost and time required to put a flood into production, the depressed condition of the market has been a serious handicap financially, and, further, has been an unfavorable influence on the planning of operations to secure the maximum recovery of the oil. Unless market conditions improve, it is certain that the effects will be shown in the yield for some time to come. Gas Developments Drilling was active in the southwestern area, chiefly in Allegany and Steuben Counties, and some notable wells were brought in that tapped the Oriskany sandstone. Altogether 42 holes were put down in the two counties, of which 31 were listed as producers and 11 were dry. The new wells gave an initial daily flow of 239,000 M cu. ft. At the close of

Jan 1, 1939

By D. H. Wertz, R. R. Furlong

Dry room equipment at Donora Zinc Works is of the design which prevailed at the time the plant was built in 1915. It consists of 11 adjoining rooms, each being 99 ft long, 11 ft wide, and 7 ft high and having a capacity for 1040 retorts. Heat is supplied by steam coils beneath the slatted wood floor and by warm air ducts at the ceiling. Drying practice is about the same as that generally followed in the industry except that, under normal zinc furnace operations, the maximum drying time is 45 days. During certain seasons of the year the drying process was seriously affected by varying weather conditions which frequently resulted in a scrap loss of 5 to 7 pct. Because of these unfavorable conditions, which caused uneven drying and strains in the retorts, increased retort failures in the zinc furnaces were recorded. Regulation of temperature and humidity under all conditions appeared to be the logical solution of this problem. Controlled drying had been developed for a number of ceramic products and investigation of several such drying processes in this area revealed favorable results. Along with control of drying conditions and the attendant decrease in scrap losses, plant operators also reported a material reduction in drying time. Another factor affecting the decision to proceed with this development was the drastic change in market conditions for retort clay. Curtailment of shipments from the chief source of supply made it necessary to proceed with blending of other available clays, but quality of these clays was questionable for adequate retort life in the 24 hr furnace cycle. Rapid furnace testing of new mixtures was desirable but impossible with the prolonged drying schedule. Therefore development of a controlled drying process for zinc re- torts offered the solution to the problem of rapid testing of retort mixtures. Description of Process and Equipment The freshly extruded retort is cylindrical in shape, 58 in. long, 9 in. id and has 1 1/8 in. side walls. One end is closed and approximately 2 in. thick. The moisture content of this "green" retort is about 17 pct which means a necessary removal of 30 lb of water per retort. Retorts are set on the slatted floor of the dry room with the closed end down. The controlled drying process depends upon the circulation of a large volume of conditioned air at low velocity. To provide for uniform distribu-

Jan 1, 1950

By Eugene S. Perry

The most outstanding event in oil and gas development in Montana during 1936 was the discovery of oil in the Baker-Glendive gas field, in the extreme eastern part of the state. Other notable achievements were small extensions in the Cut Bank oil field; continued favorable results of acidization in the Kevin-Sunburst oil field; and the discovery of oil and gas in commercial quantities about 20 miles southwest of Billings, on what is known as the Mosser dome. Several wildcat wells were drilled. For the coming year of 1937, it is anticipated that the main activities will be confined to drilling in or near known fields. During 1936 Montana had seven fields producing oil, but over 95 per cent of oil production came from four fields, which in order of importance are: Cut Bank, Kevin-Sunburst, Cat Creek and Pondera. Total production for the state was 5,850,893 bbl., which is 1,251,761 bbl. more than the total for 1935. Natural gas was produced and marketed from eight fields, most important being Cut Bank, Baker-Glendive, Kevin-Sunburst and Dry Creek. These four fields accounted for over 85 per cent of total state gas production, which is slightly greater than the 1935 production of nearly 18 billion cubic feet. Increase in gas consumption is due in part to increase in smelter operation. More detailed information pertaining to the various fields is given in Table 1. In the Baker-Glendive field a test 8186 ft. deep, 15 miles southeast of Baker, was completed by the Montana-Dakota Utilities Co. in 1936. The first gas-bearing sandstone (Judith Hiver horizon, Upper Cretaceous) was found at a depth of 528 ft., and a second sand at 1167 ft. Sandstones of the Dakota formation, in which occurred water, were found from 3724 to 3853 ft. White sandstone correlated with the Tensleep (Minnelusa) formation of Pennsylvanian age was found from 5631 to 5751 ft. deep. The lower 1900 ft. of the well (below 6278 ft.) was essentially in limestone and dolomite, and information on correlation of formations in this mass of sediments is not available at this time. The upper portion of this part of the well contained much anhydrite. Cherty and dolomitic limestone below 7000 ft. may be equivalent to limestones of the Madison formation. The thickness of strata beneath the Dakota formation was

Jan 1, 1937

By H. G. Botset

A KNOWLEDGE of the water content of producing sands is becoming of increasing importance to the petroleum industry. It is now a generally accepted fact that practically all oil sands contain some free water. Recent experiments1 have shown that an appreciable fraction of the pore space of a sand may be filled with water while oil production from this sand is water-free. Crowther and Haines,2 in experiments on electro-endosmosis in soils, reported that there was no endosmotic flow of water when the moisture content of the soil was 14 per cent or less, indicating that the moisture content of the soil below 14 per cent was held by dif-ferent forces than the water content above this value. This result is confirmed qualitatively by Dunlap,1 who found that "as the volume of water in the voids exceeds approximately 15 per cent of the pore volume, the permeability of the core to kerosene is markedly reduced." The author3 has also found in other experiments that the gas flow through a water-saturated sand reaches essentially 100 per cent when the pores of the sand still contain from 10 to 15 per cent water. The velocities of the flowing fluid in the experiments cited were comparatively high, so that in practice one may expect, at lower fluid velocities, an even higher moisture content of the sands with water-free oil or gas production. Thus a knowledge of the water content of oil-field sands becomes of con-siderable importance in estimating petroleum and gas reserves, and effi-ciency of fluid recoveries from depleted reservoirs. Rapid and reasonably accurate methods of measuring the water content of sand cores have not been described so far in any literature that has come to our attention.4 The method described below is devel-oped from methods that have been used for some time to measure the water content of alcohols.5,6,7 It is an application of the fact that in the presence of certain organic liquids such as kerosene, carbon tetrachloride, xylol, etc., water and alcohol are only partly miscible. This relation-ship has been used for some time in the study of gasoline-alcohol mixtures where the presence of small quantities of water affect the solubility of

Jan 1, 1938

By J. P. Nichols

Modern vibrating screening dates from about 1910 at which time the forerunner of the present day two bearing and four bearing circular motion inclined vibrating screens were first introduced. These simple machines consisted of a screen box holding some kind of a screening surface to which was attached an off-center shaft or a shaft with an off-center weight which was rotated. The rotation of these shafts caused a shivering motion to the screen box and produced the first vibrating screen. In the 1920's and early 30's, the box designs were improved and the mechanisms designs were also improved and by 1940, vibrating screens were an important part of most process plants. In the early days when the screen sizes were dictated by how much could be shoveled onto the screen box and by the force that a particular mechanism could produce, not much thought was given to the proper sizing of the particular units. As mechanism and body design improved the ability to predict vibrating screen capacity at various openings became more important. In the late 1930's, a set of empirical capacities came to be used. with few modifications, these capacities are still in use today, both by those companies that use a formula involving only the amount of fine material in a feed, and by those companies using a formula in which the total feed to a particular screen is used. In either method of calculation, the empirical values are based on these ideal conditions: (1) The material being fed to the screen contains 25% oversize. (2) The feed to the screen contains 40% half size material. (3) The material has a bulk density of 1.6 T/Cu.M. (100 lbs/cu.ft.). (4) The screening surface has an open area of 50%. (5) The material is dry, free flowing and relatively cubical. (6) The maximum screening efficiency required is between 90 and 95%. It is obvious that these conditions do not occur in natural or crushed size distributions. Therefore, modifications must be made to these empirical values to allow for the calculation of a vibrating screen for a particular set of conditions. Before we consider these various modifications, let us look at what happens to material as it is acted on by a vibrating screen so that we can better understand why the modifications are nec-

Jan 1, 1982

By Mungo Park, C. Baring Horwood

This paper is intended, in the light of recent investigations, to call attention to some of the essential features of good practice in sampling and mine-valuation. Mine-sampling may be divided broadly into two classes: (1) development-sampling and cornputatioll of ore-reserves; and, (2) stope-sampling and estimation of stope-values. Development-Sampling. It is with development-sampling only that this paper deals— the term development being taken to mean the opening-up of a mine by cross-cuts, drives, connections, etc., preparatory to actual extraction of the ore for milling. In development-sampling the work of the sampler and the consequent estima-

Jan 1, 1909

By Waldemar Lindgren

CONTENTS. [ ] I.-CHARACTER OF THE DEPOSITS. 1. Principal Features. IN many schemes of classification and description the term contact-deposit has been somewhat loosely applied to all accumulations of useful minerals (other than those of unquestioned sedimentary origin) which are enclosed between two different rocks. As thus used, the term may include deposits of widely differing origin, and, unless qualified, is not in place in a genetic classification. The present paper deals with a special class of contact-deposits. In many geological provinces, granular igneous rocks, such as granite, diorite and syenite, have broken through and invaded sedimentary rocks. The molten magma may in part have reached the surface and there solidified with relative rapidity as a lava. The largest masses of it, however, did not reach the surface, but cooled very slowly at considerable depth under great pressure, and eventually consolidated into a rock of granitic texture. Uplifts and extensive erosion may have followed; and at the present day, in many places, thousands of feet of material have been removed, bringing to the surface the intrusive granular rocks and their once deep-seated contacts with the sedimentaries which they shattered at the time of in-

Jan 1, 1902