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By Forrest K. Pence

BENTONITE deposits are known to occur in Texas within the Jackson group of formations. This group represents the uppermost Eocene age sediments found in the coastal plain area of Texas. It outcrops across this area of the state in a narrow band of some 4 to 20 miles width. The outcrop pattern roughly parallels the present Gulf of Mexico shore line and is some 100 miles inland from the Texas shore, Fig 1. The principal bentonite deposits are found in the areas where this outcrop pattern cuts across the south-central Texas counties of Karnes, Gonzales, and Fayette. In these deposits, the better quality bentonite is found in the lower or bottom layers of the volcanic ash deposits in which they occur. Some of these better quality bentonites develop very light colors upon firing and therefore justify their being classified as "white firing." The deposits in Karnes and Gonzales Counties apparently occur in commercial quantity, whereas the white firing strata so far uncovered in Fayette County have been too thin to be classified as yet as "commercial." A study of the ceramic properties of the weathered ash in Gonzales and Karnes Counties was reported in 1941.1

Jan 1, 1949

By L. P. Bayvel

The method of spectral transparency was investigated. A device for measuring particle sizes based on this method was developed, tested and applied. The device affords measurements of particle size distribution in the range from 0.1 to 4 µm. It proved possible to measure sizes not only of spherical particles but also of non- spherical ones. The spectral range in which it is necessary to determine transparency for particle size measurements was found.

Jan 1, 1980

By Stewart K. Griffiths

A general method-of-lines numerical approach for modeling gas driven fractures has been developed and tested. The numerical solutions agree very well with known similarity solutions for laminar and turbulent flow. Acceptable accuracy is obtained with a very few numerical grid points and with modest execution times. The model has also been checked against the results of several field tests, in which air was used to drive axisymmetric fractures into permeable tunnel-bed tuff.

Jan 1, 1984

TENTATIVE -reservations for the cruise to Vene-zuela and the West Indies have been coming in nicely, but there is plenty of room yet for mem-bers and their friends. The exact schedule is even yet not entirely fixed. Owing to difficulty in securing the release. as, early as had been hoped, of the Lapland, which is so particularly well adapted to this cruise, the time has been shortened. The steamer is now scheduled to sail at midnight on Jan. 30 or 31, the exact date still to be determined, and to return on Feb. 20. This change will so shorten the time as to permit many more to attend as they need not be so long. away from their business. It .will necessitate cutting out the pro-posed day at Kingston in Jamaica, and, if the steamer is -not available until Jan. 31, may also necessitate passing Bermuda without a stop. The time remaining will, however, allow a stop of one and a half days at Havana, a full day, on the Canal, Zone with opportunity to go through the locks, the Culebra Cut, and to see Panama, and the five days, planned in Venezuela: Just how many can be taken into Lake Maracaibo and the oil fields will depend on the local transportation that can be made available. It may be necessary to restrict this shore party as to numbers, but if so, something interesting will be provided to fill the time of the others. At other points accommodations will be ample for all Members of the excursion will get back in time to register and attend the smoker on the opening day of the meeting as also possibly the Monday after-noon sessions if any be held. The usual Institute rules for excursions will be fol-lowed assigning space in the order of application with members first. Guests vouched for by members will be heartily welcomed. The steamer rate varies accord-ing to the accommodations chosen. There are a limited number of one and two berth rooms at the minimum of $250 per passenger with plenty of room at $300 to $500, according to space and location. At prices from $750 up per passenger rooms with private bath are to be had. Plans are on the-basis of two people in a three-berth room. The steamer, which is especially fitted for crusing, has ample deck-space and numerous large

Jan 11, 1927

By L. M. Yokum

Tremendous strides have been made in front end loaders in the last 15 years. Fifteen years ago a 21/4-cu-yd front end loader was the largest standard machine you could purchase. Today there are two commercially available 15-yd front end loaders and many 10-yd loaders. The estimated total worldwide market for all front end loaders over 1 cu yd has increased to over 30,000 units yearly. The trend for front end loaders, in general, and for the mining market, in particular, is to larger and larger loaders. Today there are 18 and 24-cu-yd front end loaders in prototype form. It is not inconceivable that within another 15 years there will be front end loaders in the 50-cu-yd class with design features quite different from today's. These larger loaders are being designed at the demand of the mining industry, and the design criteria are being directed at this market area. The costs of these larger loaders may be greater per unit of capacity, but it is the intent of the various manufacturers that they will be more reliable, be easier to service, give greater availability, live longer, and cost less to maintain, than previous loaders. It is also the intent of the manufacturers to compete directly with the large mining shovel as the front end loaders become appropriately larger and more reliable. There has been some trend in this direction in the past with smaller shovels and loaders. In Table 1 are data for U.S. production of front end loaders (5 to 6-cu-yd class and 10-cu-yd class) and U.S. production of cable-operated, crawler-mounted power shovels, draglines, and cranes (11/z to 5-cu-yd class) for the years 1965 and 1970 (Source: Bureau of Census, U.S. Department of Commerce). Many believe that the decline in shovel production, in particular, is due at least in part to the acceptance of the front end loader as a primary production tool. However, the foregoing comparison is for a smaller shovel class than for front end loaders. It has generally been a rule of thumb that a front end loader is competitive on a cost and production basis with a shovel when it is approximately twice as large as the shovel. This same relationship may not hold true with the larger 10 to 15-cu-yd electric shovels, but at some point, direct competition will probably occur. Current Trends There are many trends today that are significant. One major usage trend in large front end loaders involves load and carry operations. This application is defined as "performing the functions of loading, hauling and dumping with one machine over distances within its economical limits." Many people are using front end loaders to transport material as well as load it. It is estimated that nearly half of all 10-cu-yd front end loaders sold in 1970 went into primary load and carry work. Many times, significant savings result from using the load and carry system, instead of small truck and shovel operations, for distances in excess of 1000 ft. Strip mining in coal utilizes great numbers of front end loaders in this manner. In-pit crushing of limestone is developing on an ever-increasing level, especially in Europe, and this stimulates interest in load and carry operations. In Table 2 is a cost example for 10-cu-yd front end loader in a limestone quarry. More than likely, load and carry use will continue to increase over the next few years. While some types of mining do not lend themselves to load and carry in the pit, such areas as surge piles are applicable and should be studied. In the area of machine operating cost reduction, there

Jan 1, 1974

By Lap-yan Chan

Chan and Goodman (1983) presented a procedure for simulating joint traces and identifying key blocks on an excavation. This paper defines six measures of support requirements that characterize the number and dimensions of key blocks, taking into account the frictional properties of joints and actions of support systems. When correlated with case histories, these measures of support requirements can help in choosing an optimal design for shallow excavations in discontinuous hard rocks.

Jan 1, 1984

By R. G. Weavind, R. S. Young, I. Wolf

ONE of the most important fields of investigation at the Diamond Research Laboratory in Johannesburg is concerned with improvements in metallurgical practices for the diamond mining companies, with particular reference to increased recoveries of the smaller industrial stones. Considerable work has been done on the possible application of flotation processes to the diamond industry. From the viewpoint of recovery processes, diamonds in their natural state may be grouped into two classes, the water-repellent diamonds, which adhere to a grease surface, and the water-avid diamonds, which, because of their wettability, will not adhere to a grease surface and must be recovered by means other than the grease tables used for water-repellent diamonds. Experiments in the flotation of small diamonds from both kimberlite and alluvial deposits indicate the following conclusions: Water-repellent diamonds: Satisfactory flotation of —16 mesh diamonds, which are naturally water-repellent, may be accomplished using either Aero-float 25 together with cresylic acid, or Du Pont B23 as frother together with kerosine as auxiliary oily conditioner or froth stiffener. The quantities of reagents required are of the order of 0.15 lb per ton Aerofloat and 0.18 lb per ton cresylic acid. The use of acid circuits is detrimental, and for best results a pH between 7 and 9 should be maintained. R. G. WEAVIND and I. WOLF are with the Diamond Research Laboratory, Johannesburg, South Africa, and R. S. YOUNG, Member AIME, is Director of Research, Diamond Research Laboratory. TN 76B. Manuscript, March 23, 1951. A flotation period of 5 to 10 min is necessary to insure that all floatable diamonds are removed. Diamonds larger than 16 mesh cannot be recovered satisfactorily by flotation. Xanthates do not act as collectors for diamonds, and this is probably associated with their inability to impart a water-repellent surface to this mineral. Water-repellent diamonds smaller than 28 mesh can be floated quite well by the addition of a frother alone, such as pine oil or Du Pont B23. Water-avid diamonds: Partial flotation of the smaller sizes of wettable diamonds can be achieved by preconditioning with fatty acid soaps, cationic amines, and similar reagents, which will impart a water-repellent film to diamonds. Washing to remove excess reagent, followed by flotation, will result in a fair recovery, but the latter is much lower than for water-repellent diamonds. Crushed boart: Recovery of crushed boart from the waste products of industrial uses is best accomplished by first conditioning the diamonds present in the mixture with fatty acids, cationic amines, etc., removing the conditioning agent by washing, and floating in a cell of the pneumatic type. Flotation reagents found to be most suitable are Du Pont B23, and Aerofloat 25 together with cresylic acid. The optimum quantities are 1.2 g Du Pont B23, and 0.55 g Aerofloat plus 1.4 g cresylic acid, per liter of pulp in the cell. A solids-to-water ratio of 1 to 4 is found to be the most suitable, and alkaline circuits are necessary for best results. Diamonds larger than 28 mesh are not recovered satisfactorily by this procedure, but for finer sizes flotation offers an excellent procedure for the reclamation of this strategic industrial material.

Jan 1, 1952

By J. Kinkead, R. M. Sherman, E. M. Frizzel

A recent research study performed under US Bureau of Mines Contract No. J0199088 "Modular Irrigation Equipment for Reclaimed Strip Mined Lands" investigated the feasibility of irrigation as a reclamation tool in the arid and semi-arid regions of the Western United States. Review of mined land characteristics, evaluation of irrigation systems, and assistance from the mining industry resulted in the design of two strategies for the implementation of reclamation irrigation using solid set systems. It is not the intent of this paper to suggest the generalizations made on the basis of a six state area can extend to the design of an irrigation system for a specific mine site. The purpose is to present two irrigation strategies that may be implemented with solid set irrigation in this six state area. The reader should note that the following is the result of research and, therefore, original concepts were presented. The ultimate validity of these concepts will be determined by future field tests.

Jan 1, 1983

By Fred Hellmann

IT IS hardly to be doubted that the opportunity within the grasp of the mine manager for beneficent and helpful action in relation to young engineers seeking employment under him is very broad and very big. It is my experience that a manager usually has a strong inclination to help along those who have chosen the career which he has selected for himself, and to aid them and support them as their steps tread the paths which his own feet have previously followed. He has .a strong sympathy for them in their efforts, he almost yearns to shield them from the mistakes into which he himself fell, and to assist them to avoid the pit-falls of which he knows by bitter experience. Yes, this tendency and inclination is strongly developed in most managers, and they would welcome the opportunity of extending the helping hand, if they knew precisely how best this could be done.

Jan 5, 1923

By C. N. Reid

In the course of annealing studies on molybdenum, it has been observed that a carbide precipitates preferentially on internal and external surfaces. The evidence for this is as follows. Electropolished bend specimens prepared from two grades of commercial molybdenum were loaded in a closed but unsealed tantalum can, and were annealed for 1 hr at 2000°C under a vacuum of 1 x 10-4 torr. The compositions of these materials are summarized in Table I. The samples were then slowly cooled at an average rate of 10°C per min, and were examined when cool. The surfaces of specimens prepared from Molybdenum A were consis- tently clean and featureless, except for thermally etched grain boundaries, see Fig, l(a). On the other hand, Molybdenum B had surfaces containing many needle- and featherlike markings, see Fig. l(b). These features were present in all surface grains, and within a given grain belonged to families

Jan 1, 1965

JOHN ALEXANDER MATHEWS, who has been awarded the Hunt Gold Medal for his paper "Austenite and Austenitic Steels," which was pre-sented before the Institute as the Howe Memorial Lec-ture for 1925, was born at Washington, Pa., on May 20, 1872. His interest in metallurgy may be said to be hereditary, as three generations of his Colonial forbears were gold and silversmiths. After graduating from Washington and Jefferson College in 1893, he entered Columbia University where he was successively assistant in assaying and tutor in chemistry and at the same time continued his work for the Ph. D. degree, which he received in 1898. He was at one time awarded a fellowship in chemistry, and for 1900, 1901 and 1902 re- ceived the award of the Ear- nard Fellowship for the En- couragement of Scientific Re- search, spending one year at the Royal School of Mines, in London, studying alloys un- der Sir William Roberts- Austen, another at Columbia under Henry M. Howe, and the third at Sanderson Bros. works, Syracuse. While in England, he was one of the first three, recipients of an Andrew Carnegie Scholarship of the Iron and Steel Institute of Great Britain, which later awarded him the first Car- negie Gold Medal for Re-search. He entered the employ of the Crucible Steel Company of America, at its Sanderson works, in 1902, as metal- lurgist and soon became as- sistant manager. In 1908 he ent to the Halcomb Steel JOHN A. Co., Syracuse, N. Y., as superintendent, later becoming general manager and president in 1915. In 1920 he returned to Crucible Steel Co. of America, first as vice-president and later became president from 1921 to 1924. He retired from the presidency in 1924, made a metal-lurgical trip to Europe, and returned as vice-president to resume his "favorite pastime" of directing research and development work in the production of special tool and alloy steels. He has taken a particular interest in the development of austenitic steels which, in addition to an extraordinary resistance to corrosive attack, show under fatigue, torsion, and tension tests superior qualities as compared with the ordinary engineering steels, and at elevated temperatures show remarkable resistance to oxidation and scaling and several times the strength of many of the complex alloys that are not of the natural austenitic variety.

Jan 2, 1928

By Dubois Eastman

BEHIND the contrasting liquid-fuel technologies of Germany and the United States lie the basic differences of scarcity and abundance. The chemists and engineers of each nation have developed processes that accommodate available raw materials. In the United States, processing is based on an abundant supply of petroleum, which is refined into a variety of fuels and lubricants. Germany has little indigenous petroleum but has a readily available supply of coal that can be converted into liquid fuels and lubricants. As a result, in Germany several basic processes have been developed for the conversion of coal into synthesis gas (carbon monoxide and hydrogen). In turn, this gas is processed into products. As a normal function of its researches into petroleum processing, the petroleum industry in the United States has made careful studies of various conversion and synthesis techniques. A number of oil companies are carrying out independent development programs with the aim of synthesizing hydro- carbon products that can be marketed at a price that will compete with the price of refined petroleum products. American oil companies hope to perfect synthesis processes that will directly benefit the consumer. A good example of progress in these terms is the synthesis plant at Brownsville, Texas, which is based on the conversion of natural gas to synthetic fuels and other valuable products. When this plant is operated at near capacity, it is expected that the products will be able to compete favorably for the consumer dollar. The complete gasification of coal is a technique well rooted in history. As a controlled process on a small scale, it goes back centuries. As a practical technique on a commercial scale, it dates back to 1839, when "producer gas" appeared in Germany for limited industrial use. By 1873, "water gas," or "city gas" as it is sometimes called, was being manufactured commercially in the United States for use in heaters and stoves. The water-gas process was the cornerstone for modern synthesis. To older methods that were concerned only with carbon and oxygen reactions, it added hydrogen by means of steam. Thus far the goal of conversion was to produce gas for heating, lighting, industrial use, and cooking. The long step forward to synthesis was made in 1927, when Germany started to make gasoline from coal by means of the revolutionary Bergius hydrogenation process. A year earIier, Franz Fischer and Hans Tropsch had announced their process, which finally reached the

Jan 1, 1953

By H. Krueger, H. N. Hersh

USE of autoradiography in diffusion studies offers the advantage that no repeated sectioning is necessary and that the analyses are performed in a simple manner over the continuous range of penetration depths. As part of a program of solid-state physics, it was desired to develop the autoradio-graphic method' quantitatively for use in diffusion studies. Results are reported here for the self-diffusion of silver. Silver was chosen because the existing data are good enough to evaluate the technique." The silver used in this investigation was obtained in the form of ¼ in. diam rods of polycrystalline material, 99.99 pct purity. The radioactive silver, Ag110 (ß, y), was obtained as the nitrate and converted to the chloride for use in a standard cyanide plating bath. The diffusion specimens were 1/2 in. lengths of the rod. They were mounted in bake-lite and the exposed circular face carefully ground and polished. Prior to electrodepositing radioactive

Jan 1, 1956

By R. L. Sandefur

Professor Kim's excellent review article1 on ultimate pit planning contains a statement of the apparently widely held but incorrect belief that "kriging provides information on the confidence limits around the estimate which no other extension technique is capable of supplying." If a geostatistical approach is valid, there are several good reasons for using kriging but uniquely provided confidence limits is not among them. If kriging is possible, then confidence limits can be calculated for any other linear estimate.

Jan 6, 1979

By G. W. Land, A. F. Duzy

There have been some problems associated with hot coal, defined as oxidizing coal heating toward ignition temperature, in shipments from the US to overseas markets. This paper will provide, first, a brief review, together with a selective bibliography. Second, a thorough discussion of coal oxidation is covered. Third, potential effects of storage are presented and, lastly, methods are suggested for the safe storage and bulk transfer of coal. The scope includes coal storage for power plants.

Jan 1, 1986

By W. W. Coblentz

THE constants in question pertain to the total radiation and the spectral radiation of a uniformly heated enclosure, or so-called black body. These constants have been determined for the range within which temperatures can be measured with thermocouples. Conversely, using these constants and suitable instruments, such as an optical pyrometer, for example, it is possible to determine temperatures far above the range attainable with the most refractory thermocouples. The formula of Stefan Boltzmann for expressing the total radiation of a black body is R = kT4 in which k is the coefficient or "constant" under discussion. In view of the fact that total radiation pyrometers are usually calibrated on an arbitrary scale, there is no great demand for an exact value of the coefficient of total radiation in absolute value. However, it is intimately connected with the constant of spectral radiation; hence, an accurate determination of the constant k gives a check on the constant of spectral radiation. The distribution of radiation in the spectrum of a black body is represented by Planck's equation, E? = C1?-5 (e c/?T - 1)-'. The spectral radiation constant c, in this formula, is useful in optical pyrometry and in establishing a high temperature scale. The numerical value of the constant c has been determined in the range of temperatures measurable with thermocouples and, also, by extending the temperature scale to higher temperatures by means of total radiation measurements.

Jan 8, 1919

By J. H. Keeler

QUESTIONS raised during earlier investigations of the preferred orientation in titanium1 and zirco-nium sheet led to the examination of the rolling and annealing textures of beryllium and hafnium sheet. Since the c/a ratios are 1.568 and 1.584, less than that of ideal close packing, 1.633, it would be expected that the preferred orientations would be similar to those exhibited by zirconium and titanium. This was found to be true. However, in several regards the orientations observed for beryllium differed from those reported by Smigels-kas and Barrett4 and so are given here. The okientations for hafnium are presented since only the cold-rolling texture has been reported in the unclassified literature. The pole figures were determined by transmission using an X-ray spectrogoniometer with copper Ka radiation and the automatic pole-figure recorder designed by Geisler described previously.6 The intensity units in the pole figures in this case are only arbitrary since calibration against a random sample of the same material was not considered necessary for the original purpose of the examination. The beryllium sheet, cold-rolled from 0.036 in. to 0.006 in., a reduction of about 84 pct, exhibited a split texture with the [1010] direction in the rolling direction as shown in Fig. 1. The same specimen annealed in vacuo for 1 hr at 1000°C showed no change in orientation. These textures

Jan 1, 1959

By Rossiter W. Raymond

The substance known as carbonite, or natural coke, has been several times the subject of comment before the Institute. The most important contribution hitherto made to the discussion is that of Dr. Henry Wurtz, of Hoboken,* who states, upon the strength of a chemical analysis, that carbonite is not a coke, but contains 14.08 per cent. of volatile combustible matter. In 1882 a mine was opened upon a carbonite seam, near Midlothian, Chesterfield County, Va., by Messrs. Jewett & Brother, of that place. The seam, which dips westerly at an angle of about 30 degrees, was struck at the depth of 137 feet with a vertical shaft, and followed on the dip 325 feet, at which depth gangways were opened north and sooth. For these statements (having made no personal examination of the locality), I am indebted to Mr. Albert Blair, of Richmond, and for the following section, to Mr. John Bladon, engineer at the mine. The section was taken in the face of the gangway, February 17th, 1883. It shows an aggregate thickness of 15 feet of "coke," of which about 5 feet were extracted by the system employed last winter. It is reported that under the "coke" seam there is a thick seam of highly bituminous coal, which has been extensively worked on a neighboring property, a little south of the Jewett colliery, the coal being sold for gas-waking. The carbonite is used for domestic purposes, and is said to burn

Jan 1, 1883

By M. L. Brashears, R. G. Slayback

The host dolomite of the Pine Point lead-zinc ore is a prolific ground-water aquifer that occurs locally under watertable and artesian conditions. Mining schedules and severe climate require rapid and thorough dewatering of open pits. Pumping-test methods, common to ground-water supply studies, were applied to dewatering design for a model ore pit in 1968. Procedures for testing and design at other ore bodies were established and have been carried out successfully by mine personnel. At the inception of ground-water studies, parts of ore bodies were below prevailing ground-water levels by 35 to more than 150 ft. Movement of ground water through the coarsely recrystallized dolomite occurs largely through fractures and solution openings. Because the overburden deposits consist mainly of glacial till, it is estimated that the recharge to the aquifer is about 25% of the 13-in. annual precipitation. Natural groundwater flow is northeastward toward Great Slave Lake. Background data included extensive diamond drill hole logs and cores and static level data for a number of ore pits. An ore pit, known as N-42, that required 40 ft of dewatering was selected for the initial application of the pumping-test method. Production wells, cased with 14in. pipe, were drilled to a depth of 300 ft on the rim of the ore pit. A suitable pattern of observation wells was obtained by lining 21/8-in. diamond drill holes with perforated electrical conduit. A two-stage pumping test

Jan 1, 1973

By E. H. Greener, M. E. Fine

The internal friction (1/Q) of cobalt Fig. 1 (measured by an electrostatic dynamic method1) near 250°C begins to increase rapidly on heating and continues to increase until 560°C, the highest tem- perature measured. In the plot of log of 1/Q against 1/T, above 250°C the data nearly fit two straight lines intersecting at 400°C, approximately the temperature of the hexagonal-cubic transformation. The higher temperature branch corresponds to an effective activation energy of 6500 cal per mole, the lower temperature branch 11,000 cal per mole. Young's modulus Fig. 2 increases approximately

Jan 1, 1959