Search Documents

By C. E. Shoenfelt

There was a notable decrease in drilling operations in 1940 in all of the Rocky Mountain states except Montana, where the two large fields on the Canadian border, Cut Bank and Kevin-Sunburst, were espe-cially active. The expanding markets for Montana natural gas made necessary the more intensive development of such fields as Rowdoin, Cedar Creek and Devon. While there were no important oil and gas discoveries in 1940 in any of the Rocky Mountain states, a few small pools were opened, which may constitute separate areas but may prove with later development to be extensions of old fields. Some of the old fields were extended and deeper pay zones were discovered in others. These have given the areas greatly increased oil reserves and therefore are just as important as the discovery of new fields. The more important of the developments in 1940 are given, by states, in the following paragraphs. Colorado Hiawatha Field, Moffat County.—The Mountain Fuel Supply Co. began the development at Hiawatha of its oil reserves, which were discovered in about 1929, and late in the summer oil began moving from the field by truck to the shipping point at Rock Springs, Wyoming. The Hiawatha field of northwestern Moffat County was discovered in 1927 by the Sormir Petroleum Co., with the completion of No. r Florence Wilson for 4,5,000,000 cu. ft. of gas a day from a Wasatch sand lens at 2200 it. In later development of the field, oil showings were reported in several wells but no development of this resource was undertaken until 1940, when a test of the oil possibilities was started with the release in April of a location for No. 5-A Wilson on the S\W. SW. NW. of sec. 23-1zN-1ooW., on the east side of the field. The Well had an initial production of 327 bbl. of oil a day pumping from three Wasatch (Tertiary) sands between 2005 and 2540 ft. It was drilled to 2562 ft., where the 65/8-in. casing was cemented and gun-perforated at 2005 to 2125 ft., 2260 to 2335 ft. and 2513 to 2540 ft. At the end of the year, this well was averaging zoo bbl. of oil per day, pumping. Two other wells were drilled for oil on Hiawatha during the summer—one a small well of 60 bbl. per day and the other a small gas well. Powder Wash Field, Moffat County.—The development of the Powder Wash field in northwestern Colorado was resumed in 1940 by the Mountain Fuel Supply Co., with the release of a location for No. 2-A Musser in the CWL.NW.SE. of sec. 4-1rN-97W. The Powder Wash field was discovered in 1931 by the Mountain Fuel Supply Co. and the discovery well, No. I Musser, on C.NW. of sec. 5-IIN-97W., was completed at 2152 ft. in the Hiawatha member of the nonmarine Wasatch for-mation for an open flow of 34,000,000 cu. ft. of gas per day under a natural pressure of 685 lb. per sq. inch. Oil was discovered in the Powder Wash field on Nov. 26, 1936, in the company's No. I Carl Allen on the NE.SW.SE. of sec. 32-12N-97W. The oil production was

Jan 1, 1941

By C. S. Yust, J. W. Smith, J. R. Walsh, R. E. Simpson

This paper presents the results of a complete reservoir studv designed to determine a sound economic program for the conservation of oil and gas in the Pickton field, Hopkins County, Texas. The Pickton field produces from the Bacon Lime with all indications of the study being that production is predominately by dissolved-gas drive. Calculations of the total ultimate recovery to be expected under primary operations indicated only 16.7 per cent of the oil originally in place would be recovered. This unusually low recovery is due to the type of drive operating and the extremely high dissolved gas-oil ratio and shrinkage. Results are presented for six plans of returning gas to the reservoir, evaluated to determine (1) comparative recoveries and economics of (a) returning gas at a constant rate by supplementing Pickton gas with extraneous gas during the early portion of the operation, and (b) conventional gas-return operations without using extraneous gas, and (2) the optimum size of compressor plant for each type of pressure maintenance. The over-all economic program considers, for either type pressure maintenance operation. a gasoline plant to process the unusually rich casinghead gas. Since pressure maintenance will disturb equities, pooling of royalties is in the case of Pickton a prerequisite to conservation of oil by this type of operation, both from an economic and legal standpoint. In the event pooling of royalties cannot be achieved, the study considers a gasoline plant to operate under a modified primary production operation which will make the conservation of gas possible. INTRODUCTION The Pickton field, located in Hopkins County, Texas. was discovered in November, 1944. by the completion of Humble's C. D. Nichols 1, in the Bacon lime of the Lower Glen Rose formation, through perforations from 7,888 to 7.896 feet. The well initially produced 50.2 API gravity oil with a gas-oil ratio of 1,350 cubic feet per barrel. Subsurface samples of the reservoir fluid obtained soon after completion of the discovery well showed that the Pickton crude is unique in that it has an extremely high dissolved gas-oil ratio and is subject to very severe shrinkage. Calculations of the future behavior of the Pickton reservoir indicated that ultimate oil recovery by primary operations would be 3,269,000 barrels, representing only 16.7 per cent of the oil in place (19,577,000 stock-tank barrels), and that recovery could be substantially increased by returning the produced gas. The cumulative production of 1,382,694 barrels on November 1: 1947, amounted to 42.3 per cent of the estimated ultimate oil recovery from primary operations. The purpose of this study is to determine and evaluate the optimum program for conservation of oil and gas in the Pick-ton field, including the desirability of conducting gas-return operations and of installing a gasoline plant. LOCATION AND DESCRIPTION Pickton Field, The Pickton field, as shown in Fig. 1, is located in southwest Hopkins County, Texas, 12.5 miles southwest of the New Hope field, 2.7 miles northeast of the Coke field, 16 miles southwest of Sulphur Springs, and 8 miles northwest of Winnsboro, Texas.

Jan 1, 1949

By C. S. Yust, J. W. Smith, J. R. Walsh, R. E. Simpson

This paper presents the results of a complete reservoir studv designed to determine a sound economic program for the conservation of oil and gas in the Pickton field, Hopkins County, Texas. The Pickton field produces from the Bacon Lime with all indications of the study being that production is predominately by dissolved-gas drive. Calculations of the total ultimate recovery to be expected under primary operations indicated only 16.7 per cent of the oil originally in place would be recovered. This unusually low recovery is due to the type of drive operating and the extremely high dissolved gas-oil ratio and shrinkage. Results are presented for six plans of returning gas to the reservoir, evaluated to determine (1) comparative recoveries and economics of (a) returning gas at a constant rate by supplementing Pickton gas with extraneous gas during the early portion of the operation, and (b) conventional gas-return operations without using extraneous gas, and (2) the optimum size of compressor plant for each type of pressure maintenance. The over-all economic program considers, for either type pressure maintenance operation. a gasoline plant to process the unusually rich casinghead gas. Since pressure maintenance will disturb equities, pooling of royalties is in the case of Pickton a prerequisite to conservation of oil by this type of operation, both from an economic and legal standpoint. In the event pooling of royalties cannot be achieved, the study considers a gasoline plant to operate under a modified primary production operation which will make the conservation of gas possible. INTRODUCTION The Pickton field, located in Hopkins County, Texas. was discovered in November, 1944. by the completion of Humble's C. D. Nichols 1, in the Bacon lime of the Lower Glen Rose formation, through perforations from 7,888 to 7.896 feet. The well initially produced 50.2 API gravity oil with a gas-oil ratio of 1,350 cubic feet per barrel. Subsurface samples of the reservoir fluid obtained soon after completion of the discovery well showed that the Pickton crude is unique in that it has an extremely high dissolved gas-oil ratio and is subject to very severe shrinkage. Calculations of the future behavior of the Pickton reservoir indicated that ultimate oil recovery by primary operations would be 3,269,000 barrels, representing only 16.7 per cent of the oil in place (19,577,000 stock-tank barrels), and that recovery could be substantially increased by returning the produced gas. The cumulative production of 1,382,694 barrels on November 1: 1947, amounted to 42.3 per cent of the estimated ultimate oil recovery from primary operations. The purpose of this study is to determine and evaluate the optimum program for conservation of oil and gas in the Pick-ton field, including the desirability of conducting gas-return operations and of installing a gasoline plant. LOCATION AND DESCRIPTION Pickton Field, The Pickton field, as shown in Fig. 1, is located in southwest Hopkins County, Texas, 12.5 miles southwest of the New Hope field, 2.7 miles northeast of the Coke field, 16 miles southwest of Sulphur Springs, and 8 miles northwest of Winnsboro, Texas.

Jan 1, 1949

By T. S. Liu, E. A. Peretti

A LITERATURE survey of the In-Sb system, which was made before a study of the binary diagram was undertaken, revealed that the intermediate phase InSb existed and that its crystal structure is face-centered cubic of the zinc blend type. In 1929 Goldschmidt' determined the lattice constant for InSb and obtained a value of 6.452A. A more recent value, 6.461A was reported by Iandelli2 in 1941. The purity of the indium used was not very high, however. The indium used by Iandelli contained 2 pct Ge. In view of this fact it was decided to remeasure the lattice parameter using high-purity indium (99.97+ pct In) and spectrographically standardized antimony of the highest purity available (99.91 pct Sb). Specimens corresponding to the InSb composition were made by carefully weighing the ingredients on an analytical balance and heating them in vacuo in a quartz tube at 700°C. As melting losses were negligible, the alloys were not analyzed chemically, but the intended analysis was taken as being accu- rate. Powder samples were prepared by either filing or crushing of the brittle alloy, followed by screening at 325 mesh. The powders were then annealed at 400°C in evacuated capsules for about an hour. X-ray photograms were taken with a Debye and a back-reflection focusing camera, using characteristic cobalt K. radiation. Lattice parameters were calculated by Cohen's³ method. The results of a Debye pattern and of a back-reflection pattern at 25°C are given in Tables I and 11. The lattice parameter at 25 °C is 6.47602A.

Jan 1, 1952

By G. W. Traer

THE distillation of bituminous coals at what is commonly termed low temperature, and the quantities, nature and adaptabilities of the products have been the subject of considerable experimentation, during recent years. Fortunately, the earlier work in this country was done by men whose scientific training qualified them properly to record and interpret the results of-their experiments. The work of Prof. Parr, of the University of Illinois, is especially notable in this respect. Prof. Parr's work, added to that of English experimenters, demonstrated certain things to a degree which is generally regarded as convincing. They have proved that a caking bituminous coal, when subjected to a temperature of not more than 1000° F. (preferably somewhat less) will yield light tar having low specific gravity (about 1.06) and high value; also, that this yield, with a given coal, will depend upon the percentage of hydrocarbons in the coal, the maximum temperature used, and the promptness with which the distillate gases are removed. It is assumed that air is excluded from the retort, and that the coal is subjected to heat for a sufficient time to drive off all of the tarry hydrocarbons. The results attained in the first, or low-temperature stage of the Carbocoal process, recently described by C. T. Malcolmson, corroborate these general principles. It is the purpose of the writer to describe other work of a practical nature, directed toward the commercial adaptation of these principles, which was begun nearly two years ago; this investigation was assisted by A. J. Sayers, of the Link-Belt Co., and Carl Scholz.

Jan 9, 1918

By John Griffen, David H. Davis

Much of the ground to be covered by this paper was ably covered by a paper presented by Messrs. Morrow and Jordan1 before a joint meeting of the Iron and Steel Section of the Engineers Society of West-ern Pennsylvania and the A.I.M.E. Pitts-burgh Section at Pittsburgh in the spring of 1940. As that paper was not published, the present authors have availed them-selves of Mr. Morrow's kind permission to use information given therein. Similar figures for the latest years available have been added to many statistics originally presented. It is unfortunate that Mr. Jordan's death removes his stimulating guidance and help, which the authors would have welcomed and have found invaluable in the past. One interested in the Pittsburgh seam should not fail to read the exhaustive and authoritative paper by Eavenson2 presented in 1938. As Allegheny, Fayette, Greene, Washington, and Westmoreland Counties contain practically all the reserves and furnish nearly all of the production from the Pittsburgh seam in Pennsylvania at the present time, this area only is intended when reference is made to the Pittsburgh seam in Pennsylvania. On much of the seam in Greene and Washington Counties, which contain a large proportion of the total reserves, insufficient data are available to determine the detailed characteristics of the seam with any degree of finality. It is hoped that the data presented here will fairly well indicate the probable characteristics. Economic Importance of the Pittsburgh Seam The Pittsburgh seam in Pennsylvania is of primary importance as a coal resource, not only because of its substantial reserves but because it contributes such a large proportion of the coal used in the country and an even larger proportion of that used in the manufacture of coke. Mr. Ashley3 placed the estimated recoverable reserves (1935) of the Pittsburgh coal bed in Pennsylvania at 7,500,000,000 tons.* Although a considerable portion of this tonnage is not now suitable for coking coal, because of its high sulphur content, undoubtedly the supply of coking coal will last for many years and that not suitable for coking will furnish industry with an ample supply of energy. In attempting to assess the contribution of the Pittsburgh seam to total coal production and to that of coal used in making coke, one finds that the statistics published annually by the U. S. Bureau of Mines, Minerals Yearbook, do not give tonnages classified as to seams but only as to districts or states and counties. However, it happens that, at present and during much of the

Jan 1, 1944

By David H. Davis, John Griffen

Much of the ground to be covered by this paper was ably covered by a paper presented by Messrs. Morrow and Jordan1 before a joint meeting of the Iron and Steel Section of the Engineers Society of West-ern Pennsylvania and the A.I.M.E. Pitts-burgh Section at Pittsburgh in the spring of 1940. As that paper was not published, the present authors have availed them-selves of Mr. Morrow's kind permission to use information given therein. Similar figures for the latest years available have been added to many statistics originally presented. It is unfortunate that Mr. Jordan's death removes his stimulating guidance and help, which the authors would have welcomed and have found invaluable in the past. One interested in the Pittsburgh seam should not fail to read the exhaustive and authoritative paper by Eavenson2 presented in 1938. As Allegheny, Fayette, Greene, Washington, and Westmoreland Counties contain practically all the reserves and furnish nearly all of the production from the Pittsburgh seam in Pennsylvania at the present time, this area only is intended when reference is made to the Pittsburgh seam in Pennsylvania. On much of the seam in Greene and Washington Counties, which contain a large proportion of the total reserves, insufficient data are available to determine the detailed characteristics of the seam with any degree of finality. It is hoped that the data presented here will fairly well indicate the probable characteristics. Economic Importance of the Pittsburgh Seam The Pittsburgh seam in Pennsylvania is of primary importance as a coal resource, not only because of its substantial reserves but because it contributes such a large proportion of the coal used in the country and an even larger proportion of that used in the manufacture of coke. Mr. Ashley3 placed the estimated recoverable reserves (1935) of the Pittsburgh coal bed in Pennsylvania at 7,500,000,000 tons.* Although a considerable portion of this tonnage is not now suitable for coking coal, because of its high sulphur content, undoubtedly the supply of coking coal will last for many years and that not suitable for coking will furnish industry with an ample supply of energy. In attempting to assess the contribution of the Pittsburgh seam to total coal production and to that of coal used in making coke, one finds that the statistics published annually by the U. S. Bureau of Mines, Minerals Yearbook, do not give tonnages classified as to seams but only as to districts or states and counties. However, it happens that, at present and during much of the

Jan 1, 1944

By E. H. Cho

INTRODUCTION Activated charcoal has been used for several centuries in many capacities including the recovery, isolation and purification of various materials (1). The first use of charcoal in a gold metallurgical system was in the extraction of gold after chlorination (2, 3,4). The gold was dissolved in a chlorine system and subsequently filtered through charcoal. The application of charcoal with cyanide extraction was patented by Johnston (5) in 1894 and adopted commercially in Australia in 1897. The process consisted of dissolving the gold and silver in a potassium cyanide solution and passing it through a series of charcoal filters. The charcoal was subsequently smelted to recover the gold and silver. The interest in the use of charcoal diminished in the first part of the twentieth century as the practice of the use of zinc as a precipitating agent increased. However, in 1916, the Yuanmi Mine in Australia replaced their zinc precipitation plant with a charcoal adsorption plant. In 1926, Scott and Gross (7) of the U. S. Bureau of Mines con- ducted extensive research on the adsorption of gold and silver from cyanide leach solutions. Among their findings was the result that the most important factor in improving the adsorptive power of charcoal was heat treatment with oxidation by air or steam. The work of Zadra (8) in 1952 stimulated renewed interest in the use of activated charcoal in gold and silver recovery with the development of a method of recovery of the gold and silver from the charcoal other than its destruction by burning. The process involved simultaneous desorption

Jan 1, 1983

George Edward WebbeR, a member of the Institute since 1906, died in San Francisco, May 29,1922. Born in Dixmont, Me., in 1852, he went to California in 1857 where he lived until 1883 and received a thorough training in precious metal mining in the employ of his father and J. B. Haggin. In 1883, he went to the Black Hills, South Dakota, as superintendent of the Father DeSmit mine; later the Deadwood Terra also came under his management. These mines are now part of the Homestake Mining Co. In 1889, the Rothchilds asked Hamilton Smith to recommend an engineer to take the place of the late Henning Jennings, who had resigned from the El Calloo Mining Co., of El Calloo, Venezuela, in order that he might proceed to South Africa. Mr. Webber accepted the position, remaining there until 1893 when he returned to the United States on his way to Johannesburg, South Africa, where he had been appointed manager of the Crown Reef Mining Co., Ltd. Early in 1896, he became general manager of the Rand Mines, Ltd., and served in this capacity until 1911. During the latter part of this period, Mr. Webber was active in the greater amalgamations of H. Eckstein & Co., and it was largely on his advice that H. Eckstein & Co. carried out the negotiations preceding the formation of the Crown Mines, Ltd. On his retirement from South Africa, he returned to live in Ross Valley, near San Francisco, Cal. The Rand Mines, Ltd., of which Mr. Webber was general manager, was the largest company controlled by Wernher Beit, the leading London house interested in South Africa mining, whose local agents in Johannesburg were H. Eckstein & Co. This firm is now known as the Central Mining & Investment Corpn., and after the departure of Henning Jennings, Mr. Webber was the firm's most valued and confidential advisor and was very highly thought of in mining circles in South Africa. He was a ma of most upright and straightforward high character, plain spoken and sincere; and his recognized high character was one more qualification which aided his great success.

Jan 1, 1923

George Edward WebbeR, a member of the Institute since 1906, died in San Francisco, May 29,1922. Born in Dixmont, Me., in 1852, he went to California in 1857 where he lived until 1883 and received a thorough training in precious metal mining in the employ of his father and J. B. Haggin. In 1883, he went to the Black Hills, South Dakota, as superintendent of the Father DeSmit mine; later the Deadwood Terra also came under his management. These mines are now part of the Homestake Mining Co. In 1889, the Rothchilds asked Hamilton Smith to recommend an engineer to take the place of the late Henning Jennings, who had resigned from the El Calloo Mining Co., of El Calloo, Venezuela, in order that he might proceed to South Africa. Mr. Webber accepted the position, remaining there until 1893 when he returned to the United States on his way to Johannesburg, South Africa, where he had been appointed manager of the Crown Reef Mining Co., Ltd. Early in 1896, he became general manager of the Rand Mines, Ltd., and served in this capacity until 1911. During the latter part of this period, Mr. Webber was active in the greater amalgamations of H. Eckstein & Co., and it was largely on his advice that H. Eckstein & Co. carried out the negotiations preceding the formation of the Crown Mines, Ltd. On his retirement from South Africa, he returned to live in Ross Valley, near San Francisco, Cal. The Rand Mines, Ltd., of which Mr. Webber was general manager, was the largest company controlled by Wernher Beit, the leading London house interested in South Africa mining, whose local agents in Johannesburg were H. Eckstein & Co. This firm is now known as the Central Mining & Investment Corpn., and after the departure of Henning Jennings, Mr. Webber was the firm's most valued and confidential advisor and was very highly thought of in mining circles in South Africa. He was a ma of most upright and straightforward high character, plain spoken and sincere; and his recognized high character was one more qualification which aided his great success.

Jan 1, 1923

The following is an incomplete list of members and guests who called at Institute headquarters during the period Apr. 10, 1919, to May 10, 1919. Arthur K. Adams, Spencer, Mass. Ensign Floyd D. James, U. S. S. Fulton. W. T. Bates, New York City, N. Y. J. Harry Johns, Thorsden, Woking, A. D. Brokaw, Washington, D. C. England. E. H. Clausen, San Francisco, Calif. W. F. Jones, Rock Springs, Wyo. W. M. Corse, Mansfield, Ohio. E. L. Lasier, Washington, D. C. E. O. Daue, Philadelphia, Pa. John M. Lovejoy, New Rochelle, N. Y. G. D. Dub, Washington,, D. C. 2d Lieut. James F. Magee, Lancaster, S. B. Eaton, Dover, N. J. Pa., Sherman Eaton, Smethport, N. C. Ernest Marquardt, Casper, Wyo. J. A. Endweiss, La Jolla, Calif. Geo. B. Marshall, Abangarez, Costa Edgar W. Engle, North Chicago, Ill. Rica. 2d Lieut. Maxwell E. Erdofy, New York Benj. L. Miller, So. Bethlehem, Pa. City, N. Y. Major Desaix B. Myers, Camp Mills. Chas. A. Fellencer, Allentown, Pa. Edmund Newton, New York City, N. Y. Arthur Feust, Joplin, Mo. Seely B. Patterson, Jr., Allentown, Pa. Ensign Harold P. Ford, U. S. S. Radnor. Wm. R. Pearson, New York City, N. Y. A. D. R. Galloway, Accra, West Africa. Harold C. Price, Langeloth, Pa. R. C. Gosrow, Milwaukee, Wis. T. C. Roberts, East. Orange, N. J. C. A. Grabill, El Paso, Tex. P. H. Royster, Washington, D. C. Hobart A. Hanks, San Francisco, Calif. W. H. Staver, New York City, N. Y. John L. Henning, Lake Charles, La. N. L. Wimmler, Bangkok, Siam. 1st Lieut. J. Parke Hook, Philadelphia, Capt. Jay P. Wood, New York City, Pa. N. Y. An item in the May Bulletin made it appear that Frank W. DeWolf had just become connected with the State Geological Survey of Illinois. This was one of the inadvertences of war. Mr. De Wolf has been Director, or Chief, of the State Geological Survey for approximately ten years. Through the courtesy of the Governor of Illinois, lie was loaned to the Bureau of Mines for about seven months, after which period he resumed his former position.

Jan 6, 1919

By Persifor Frazer

The mines which I am about to describe are all situated in the northern part of the States of Nuevo Leon and Coahuila, Mexico, between the twenty-sixth and twenty-seventh degrees of latitude. They might be grouped, orographically, into four classes: 1. Those in the Sierra de la Ygnana chain; 2. Those in the Sierra de Gomez chain; 3. Those in the Cerro Mercado; 4. Those in the Sierra de San Marcos chain. (See large map.) The first two of these may be further arranged in one geographical district, to which the name, "the Villaldatna. district," may be applied, and the last may be ascribed to the geographical district of " Monclova." Geologically described, the country rock, in which four of the six mines occnr, is a limestone, concerning which a few words will be said further on, to wit.: The Arroyo (gulch), the Montanos and the Pinitos (pines), in the Villaldama district, and La Paloma (the dove), or Iron Mine, in the Monclova district. The San Rafael appears to lie in granite, or a heavy-bedded gneiss, presenting most of the characteristics of the latter, though the contact plane of the limestone is not far off. It is certainly worthy of attention that the ore occurs in that portion of the crystalline rock, which is nearest to the limestone, and it has been thought by some observers to be a true contact vein. It is well known that veins of this character are very often distinguished for constancy and richness. Although the undersigned cannot entirely free himself from the impression that this proximity of different formations has had an important influence in the origin of the part of the vein on which this mine is situated; still he was unable to establish it actually at the contact of the limestone and granite, but rather a short distance within the latter. Two openings of the Riojas vein were respectively in limestone and in rotten whitish granite, but this fact, if established (as by the correspondence of the strike line of the vein in direction with that of a line joining the

Jan 1, 1884

By Howard L. Hartman

Probably no aspect of underground excavation is as important or as neglected as the environment. The Committee on Rapid Excavation, formed by the National Academy of Engineering to study the technological needs for "rapid" underground excavation in tunnels, shafts, and mines of the future, encountered a blank wall in attempting to evaluate environmental needs. In fact, so little quantitative information on the extent of present-day hazards is available that projection of future environmental-control demands must await more adequate assessment of current hazard levels. Further, there are not even accepted tolerance standards for many environmental conditions, such as heat, noise, and illumination. Only certain atmospheric contaminants have been satisfactorily catalogued. Any technical study, therefore, which purports to examine the state-of- the-art on underground environmental control must, in reality, settle for a cursory survey of a rather nebulous subject. ENVIRONMENTAL HAZARDS To contend adequately with hazards in the underground environment requires some knowledge of their nature and characteristics. In this regard, it is helpful first to identify our concern: when, where, and to whom or what may environmental conditions constitute "hazards"? Table 1 summarizes considerations that are important in this regard. For the purposes of this Conference (and book), primarily directed toward the excavation process itself, the hazards of consequence occur during excavation (item A) and primarily within the excavation (item B). However, some attention must be given to external hazards as well, since these may affect excavation. The object of concern (item C) is mainly human safety, although property security is also important. Hazards occur in a variety of forms. If one is to devise suitable control

Jan 1, 1970

By Strathmore R. B. Cooke, Robert E. Brandt

EARLIER work1,2 has shown that the strength developed by fired magnetite pellets containing silica or silicates is due to three separate effects. Two of these are associated with the formation of slag in the interior of each pellet at temperatures above 1000°C, where the atmosphere is substantially though temporarily neutral. The third is independent of the silica content and is responsible for the development of a hard shell around the pellet during the initial stages of firing, a condition which permits the pellet to assume the increasing load of the overlying burden and prevents extrusion of the slagged and semi-liquid interior. Pellets made from hematite concentrates do not show these effects unless specific additives are incorporated, and it is these differences in behavior which in large part account for the difficulty in producing satisfactory pellets from such concentrates. Elsewhere it has been stated that "the most important factor responsible for the development of strength in fired magnetite pellets containing no additive is the oxidation of magnetite to hematite and the subsequent recrystallization and grain growth of this constituent."1 The object of the investigation reported in the present paper was to study in detail the mechanism described above and to evaluate its contribution to the strength of the fired pellet compared with other possible mechanisms, excluding slag bonding. This was effected by placing together polished faces of two cubes prepared from specific minerals and then heating them under constant pressure at different temperatures both in air and in nitrogen.

Jan 4, 1954

By Jeffrey L. Thompson, Kenneth A. Gutschick, Robert C. Freas, Robert S. Boynton

Lime, the "versatile chemical," is, generally speaking, a calcined or burned form of limestone commonly known as quicklime, calcium oxide or calcia, or, when water is added, calcium hydroxide or slaked lime. Almost 40 different lime products are available, a fact which has contributed to the rather loose use of the term lime as well as to much confusion and misunderstanding. The term is frequently, albeit erroneously, used to denote almost any kind of calcareous material or finely ground form of limestone or dolomite. Lime is usually made from high-calcium or high-magnesium limestone, generally having a minimum of 97% combined carbonate content. Normally, high-calcium limes contain less than 5% MgO. When the lime is produced from a high-magnesium limestone, the product is referred to as dolomitic lime. Calcination, or the production of lime, has its origins in the earliest days of alchemy, with the general reaction class having been identified in an Arabic text printed in 1000 A.D. It was much later, however, in the mid-1700s to the mid-1800s before this basic reaction became understood from a scientific perspective. The production of lime has been so basic and simple that its underlying scientific principles have over the years received only intermittent investigation. Rather, much of the thought and inquiry has been directed toward the development of kilns. Thus, it has only been in the last 15 to 20 years that lime has received any concentrated scientific investigation relative to the thermodynamics and kinetics of the calcination and hydration reactions. Calcination refers to a broad class of reactions, of which the lime/limestone reaction is just one, wherein a substance is heated to less than its melting point, resulting in a weight gain or weight loss. In the calcination of limestone to produce lime, the basic chemical reaction is as follows: [CaCO3 (limestone) + heat (1000° to 1300°C)= 100 CaO (quicklime) + CO2 T 5644 or CaCO3 • MgCO3 (limestone) 10084 + heat (900°C to 1200°C) CaO • MgO (quicklime) + 2CO2 T 56 4088] While there is nearly universal agreement about the equilibrium conditions related to the limestone/lime reaction above, there have been numerous and varied calcination models developed for the reaction. Recent investigations have resulted in the development of the model shown in Fig. 1. From this model it can be seen that calcination is a function of both temperature and CO2 pressure. It does not, however, provide any indication of the rate at which the reaction takes place. Calcination is strongly time variant with different limestones. In a very broad sense this relates to the fact that the calcination reaction starts on the exterior surface of the limestone and then proceeds toward the center. As the calcination reaction takes place, the CO2 released at the reaction interface must make its way through the lime to the exterior surface. Therefore, because calcination is limited by gas diffusion to the surface of the partially calcined limestone, natural impurities in the stone, differences in crystallinity, grain boundary chemistry, density variations, and imperfections in the atomic lattice all play a significant role in

Jan 1, 1983

By E. S. Bardwell

THE reverberatory copper-refining furnaces at the Great Falls Reduction Dept. of the Anaconda Copper Mining Co. have used successively, as fuel, lump coal on grates, pulverized coal, oil and natural gas. In no other plant, so far as can be ascertained, has such a variety of fuels been used. This fact affords a unique opportunity for comparing the relative efficiency obtained with these several fuels under nearly identical conditions. FURNACES The present furnace refinery at Great Falls was placed in operation in April, 1916. The original installation consisted of two furnaces, each with hearths 36 by 14 ft. and provided with fire boxes 10 by 12 ft. for firing lump coal on grates. These furnaces had air-cooled sand bottoms and chrome-brick side walls both above and below the metal line. The roofs were of 12-in. silica brick. Each furnace was provided with a waste-heat boiler of approximately 400 boiler-hp. capacity. We soon found that chrome brick was very unsatisfactory as sidewall material because of its excessive spalling. At the first opportunity the furnaces were rebuilt, using magnesite brick below the metal line and silica brick from the metal line to the roof. At the same time the thickness of the side walls was increased, thus decreasing the width of the hearth to 13 ft. At about this time also, the thickness of the furnace roofs was increased from 12 to 15 in. No further changes occurred in furnace design until 1922, when the use of lump coal on grates was abandoned in favor of pulverized coal.

Jan 1, 1932

By F. J. Budin

Steel supports are increasingly used in metal mines for junctions, chambers, and other wide openings and for semi-permanent areas such as haulageways, shaft stations, and pump rooms. Steel lasts longer-especially in wet mines and where foul air is present-and is procurable in different sizes that will carry heavier loads than any timber of equivalent cross section. The chief advantage of steel supports is that less excavation is needed than with timber support of the same strength, so that faster progress can be made. Since there is no possible way to calculate the exact weight on supports, sizes must be chosen by experience. Any adjustment and cutting of steel supports underground would be costly and time-consuming, and it is therefore advisable to cut sets beforehand at the surface workshops. This requires standardization of sets. All these problems have been recognized at Bawdwin Mines, Burma, where mining is difficult, slow, and very expensive. The lead-silver ore is very brittle, with hanging and footwall rock of unconsolidated rhyolite tuff. During the rainy season from May to October water penetrates into the mine, and where soft rock is present disintegration into a loose mass around openings can be expected. For this reason heavy 10x10-in. timber caps break quickly in drifts and crosscuts, and timber rots in a very short time. An average increase of 50 pct in both maintenance work and costs could not be avoided.

Jan 3, 1960

By Reamy Joyce

CONDITIONS in underground mining are so variable that in approach-ing the problem of the economies effected by the use of pressure-treated mine ties and mine timbers, it is necessary to secure specific data for each mine. Facts must first be dug out to show the service life of untreated timber and the reason for its failure. Generally speaking, decay is the usual cause of failure, but in some mines mechanical destruction is an important factor. Occasionally the two causes combine to produce fail-ures, and it is difficult to determine positively which factor is responsible. In making comparisons, it is always necessary to start with the cost in place and for this reason there must be accurate information covering the labor cost of installation and the labor cost of renewals. When treated timber is used, it is necessary to know the specifications for the treating process, whether the timber was painted, dipped, treated open tank, or impregnated under pressure according to standard specifica-tions. It is also necessary to know the preservative used and the amount of the preservative that was retained by the timber after treatment. It is also well to know whether the timber was thoroughly air-seasoned before treatment or was green at the time it was treated. The kind of timber available, both untreated and treated, must be known and all of the factors listed above must be taken into consideration in the study of any problem.

Jan 1, 1939

Alexander N. Winchell, Butte, Mont. (communication to the Secretary): Mr. Spurr calls attention to the fact that an ore-deposit may be due to a succession of concentrations at different geological epochs. He cites an example of such a condition on Napoleon creek, a branch of Forty-Mile creek, Alaska. It will perhaps be of interest to call attention to another example of the same general character, not so remotely situated. The example referred to is located on Pole creek, a tributary of Cherry creek, in the extreme northeastern part of Madison county, Montana. An excellent geological map of this region is to be found in the Three Forks folio (No. 24) of the United States Geological Survey. According to this map, Pole creek, in its upper course, occupies the contact between the " Flathead " formation, which Peale correlates with the Middle and Lower Cambrian, and an area of gneisses and schists supposed

Jan 1, 1903

By G. L. Oldright, Henry de Rycker, S. F. Ravitz

The upper limit of richness of concentrates that can be smelted by means of the blast furnace without added diluents is fixed by the operation of sintering. A sinter feed with normal gangue constituents, containing more than about 50 per cent of lead, tends to fuse; as a result, air does not come sufficiently into contact with the sulphides at roasting temperatures, and sulphur elimination is poor. Since most lead concentrates now contain 55 to 80 per cent lead, it is necessary to add diluents to lower the grade of such sinter feed to about 50 per cent or less. This not only entails the expense of providing barren diluents when adequate diluents containing precious metals are not available but also appreciably lowers the capacity of the blast furnace to produce lead and increases slag losses. Attempts to desulphurize rich lead concentrates by methods other than sintering have not proved successful. Flash roasting, for example, converts much of the lead sulphide to lead sulphate rather than to oxide. However, this suggested the possibility that deliberate flash roasting of the concentrates to sulphate, followed by sinter roasting of the resulting product, might prove promising, particularly inasmuch as the elimination of sulphur from lead sulphate requires heat alone and not contact with atmospheric oxygen. The sintering of lead sulphate products has additional interest because important amounts of such products are now treated by lead smelters. Considerable quantities of lead sulphate are present in rich lead flue dusts and other by-products; lead-chamber sulphuric acid plants and other

Jan 1, 1944