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By E. P. Pfleider, E. G. Malmlow, F. Landau

Friction drive hoists, long popular on the Continent, are now being installed in the U. S. and Canada by the Swedish firm of ASEA. Invented by C. F. Koepe and used first in 18.77, the principle is the same as that in elevator installations throughout the world. Inherent advantages of this system of hoisting were not fully developed until the recent introduction of the multiple-rope principle and design of concrete tower installations. Operators have a choice of independent operation of single skips and cages using counterweights, or use of skips or cages in balance. Also, hoisting control may be automatic, push button, or manual.

Jan 1, 1955

By Waldemar Lindgren

No one would maintain that all ore deposits or all deposits of useful minerals have been formed by the same processes. Generally they have originated by special processes of concentration but these may be of many different kinds. Some deposits have their origin in chemical or biochemical processes of concentration in rivers, lakes or seas, others developed on land by means of chemical reactions of surface waters on various forms of rocks. Certain insoluble substances remained behind; others were dissolved and precipitated in favorable places. This action proceeded in the realm of the oxidizing surface waters or in the deeper zones to which the waters from the surface could find their way. Examples of the latter kind may be found in the extensive copper and vanadium deposits of some sedimentary beds or in the lead and zinc deposits of certain broad limestone strata. In these instances the evidence for any other mode of origin would seem to be very weak indeed.' Nor does it seem possible to deny that circulating waters may form deposits of the more common metals along fissures after having dissolved many constituents from paths traversed. Another very large class has been formed by magnetic processes of concentration. The last 40 years have been a period of intense activity in the investigation and description of a vast number of deposits; all modern methods have been employed and the result is an accumulation of data, difficult or impossible to master. It has been a period similar to that in petrography. The generalizations, the able deductions, have lagged behind. Evidently several geologists have become weary of this "infinite detail" and a mistrust of the microscope seems to have arisen. Although this feeling of being swamped in microscopic detail is a painful experience, nevertheless only through the detail in combination with the large features, and only by utilizing all the related sciences shall we

Jan 1, 1927

By E. C. Harder

HERBERT K. SCOTT, London, England (communication to the Secretary*).-I am acquainted with the manganese-ore deposits of Russia, India and Brazil, and agree generally with the statements contained in the paper regarding those deposits. The information given by Mr. Harder regarding the Chilean deposits is very welcome. When examining the Caucasian deposits, I endeavored to determine the quantity of ore originally contained in the deposit, and by deduction, the amount remaining for extraction. These calculations were rendered possible by the great extent of the outcrop and the extensive work that had been carried on in the deposit. In making the first estimate, the quantity of manganese ore and associated sterile material in the bed was measured in a large number of

Jan 12, 1916

By C. E. Brukl, E. Rudy, St. Windisch

The ternary-alloy system Nb-Mo-C was investigated by means of X-ray, melting point, DTA, and metallo-graphic techniques; a complete phase diagram for temperatures above 1500°C was established. Above 1960°C, niobium monocarbide and the cubic (Bl) high-tenzperature phase in the Mo-C system form an uninterrupted series of solid solutions. The ternary range of the pseudocubic q MoCl-, is very restricted. Dimolyb-denum carbide dissolves up to 44 mol pct Nb2C (2240°C), whereas the maximum solid solubility of MO2C in Nb2C does not exceed 5 mol pct. The order-disorder transformation temperatures in Mo2C and Nb2C are lowered by the mutual metal exchanges. Six invariant (p = const) reactzons occur in the ternary system; three correspond to class 11-type four-phase reactions involving a liquid phase, one to a class I (eutectoid)-type, and two further isotherms are associated with limiting tie lines. The results of the Phase diagram investigation are discussed, and the thermodynamic interpretation identifies the low relative stability of the binary sub-carbides in conjunction with the large stability diflerences between niobium and molybdenum carbides as the cause for the formation of a stable equilibrium between the monocarbide and the metal phase in the ternary reson. Due to their refractoriness, the carbides of the high-melting transition metals have received increased interest in recent years as base materials in composite structures for aerospace applications at high temperatures and for the development of self-bonded cutting tool materials; other novel fields of application include power reactors, where operation at high temperatures becomes essential for attaining high power efficiencies. In these applications, the increased reaction rates at high temperatures require a close consideration of the chemical interactions between the alloy constituents. As a consequence, a detailed knowledge of the phase relationships in the alloy systems is required in order to provide a sound basis for developmental -type work. Partly as a result of the considerable experimental difficulties associated with the investigation of this high-melting alloy class, no complete studies of ternary metal-carbon systems have been performed until recently. Even the high-temperature phase relationships in the binary transition metal-carbon systems have been delineated only during the past few years to a degree of accuracy required for a more detailed study of ternary or higher-order alloys. In recent investigations of binary and ternary systems of refractory transition metals with carbon, boron, and silicon,&apos; alloys from the ternary systems Nb-Mo-C became of interest because of the demonstrated possibility2,3 of obtaining compatible composites based on metal + monocarbide combinations. In the meantime, however, studies in other, but related, ternary metal-carbon systems, such as Ta-W-C, have shown that the solid-state equilibria may change significantly toward higher temperatures (>2000°C), and that extrapolations based on low-temperature equilibrium data are, in general, not very reliable. Although the lower-temperature (<2000°C) phase relationships in the Nb-Mo-C system are similar to those found in Ta-W-C, a cursory thermodynamic analysis of the equilibria indicated4 that complete solid-solution formation between Mo2C and Nb2C should not occur at higher temperatures. The present work was conducted in order to experimentally verify these expectations and, in addition, to provide phase equilibrium data in the melting range of the alloys. In the boundary systems, niobium and molybdenum are known to form a continuous series of solid solutions.576 The continuous solubility was also confirmed by Kornilov and Polyakova,7,8 who also observed a minimum melting point at 22 at. pct Mo and 2345°C. The phase diagram investigations of the Nb-C system by Storms and Krikorian9 and Kimura and Sasaki10 were recently supplemented by Rudy et al.11,12 The system contains a high-melting monocarbide with the B1 structure, Table I, and a subcarbide, Nb2C, which exists in at least two different states of sublattice order at low temperatures47"-&apos;3 and a disordered state above approximately 2500°C.11,12 The melting-point measurements by Rudy et al .11,14 are in close confirmation of the data by Kimura and Sasaki.10 The rather complex phase relationships in the Mo-C system were only recently Clarified.15,18 The system is characterized by three congruently melting, intermediate phases, MozC, ? MoC1-x and a Mol-,, Table I, of which only Mo2C is stable at temperatures below 1650°C. Substoichiometric MozC exists in several states of sublattice order which interconvert in homogeneous phase transitions. Hyperstoichiometric compositions cannot exist in the ordered state. Upon cooling through a critical temperature range, the

Jan 1, 1968

The Nominating Committee for Institute Officers in 1953, John R. Suman, chairman, completed its work at the Annual Meeting in February, and has made its report to the Board of Directors. The President-Elect in 1953 serves as President in 1954. The ticket follows: For President-Elect and Director, Leo F. Reinartz; for Vice-President and Director, A. B. Kinzel and Lloyd E. Elkins; for Director, Hjalmar W. Johnson, Philip Kraft, Gail Moulton, Edwin L. Oliver, Philip Wilson, and Elmer Isern. Mr. Reinartz is a vice-president of the Armco Steel Corp., Middletown, Ohio. As required by the bylaws, brief biographical sketches of the nominees will be published in the July issues of the journals.

Jan 1, 1952

By E. J. Horwood

The varying physical character and large extent of the Broken Hill lode necesarily involve the employment of a variety of underground methods. The lode had its origin in an extensive fault plane traversing metamorphosed schists conformably, as a rule, with their beds of stratification. The underground waters carrying minerals in solution deposited their contents in the original cavities formed by the faulting action, and in the enlargements of these cavities due to dynamic forces brought to bear on the rocks, more especially on the hanging-wall side of the fault. This deposition was supplemented by metasomatic replacement of a portion of the original rock contents by the argentiferous sulphides of lead and zinc which form the staple products of the district. Although the orebody is practically continuous throughout the mines, its width varies greatly, ranging from a few feet to about 350 ft. The widest portions occur in conjunction with huge folds in the inclosing country rock, almost exclusively on the hanging-wall side. The ore in these folds pitches to the south in the southern half of the field, and to the north in the northern half; there are, however, undulations in these ore channels evidently due to compression of the rocks in the direction of the channels. In the earlier days, before the orebodies had been opened up, vertical cross-sections across these bulges in the hanging wall gave the lode the appearance of the "saddle formation," so well exemplified at Bendigo in Victoria; but subsequent development of the ore channels has long since proved that the formations in the two districts are entirely different. The depth reached by the zone of complete oxidation of the sulphides varies from about 259 to 550 ft, from the original outcrop, while partial oxidation extends in places below the 1,000-ft. level. The result of oxidizing influences has been the production of ore of every grade of cohesive-ness, from that of dry sand to that of hard compact rock. The methods of mining followed in this field, and even in individual mines, are varied in accordance with the character of the ore. The general practice of the field is to sink vertical shafts, generally on the foot-

Jan 1, 1916

By G. G. Sarkar

SHARPNESS of separation and washing efficiency are often confused. The sharpness index indicates the precision of a washing unit; the washing efficiency takes into account not only the unit&apos;s precision but also the washability characteristics of raw coal and the near-gravity materials at the effective density of cut. A sound basis for evaluating the sharpness index is essential in comparing the sharpness of separation attained by different cleaning units. Sharpness Index and Related Criteria: Washing plant sharpness of separation has been well represented by Hancock&apos;s efficiency chart and Tromp&apos;s curve of migrated materials. Some useful coefficients derived from Tromp&apos;s curve-the error area, probable error, and imperfection value-have been widely used to measure sharpness of separation. These are defined in a number of papers presented at the first and second International Coal Preparation Conference held in Paris (1950) and Essen (1954).1-5 In evaluating the performance of a dense medium separator at four different gravities, Yancey and Greer6 observed that even with similar operating conditions and the same size grading of feed, the imperfection value of a washing plant varies through a greater range than the probable error. The present writer also observed the same type of anomalies in comparing the imperfection values of one plant which were determined under almost identical conditions. He therefore devised a graphical method to evaluate a washing unit&apos;s sharpness of separation and define it by a single coefficient, which is substantially independent of coal characteristics under normal operation of the unit. Unlike imperfection value, the new coefficient can be expressed on a percentage basis.

Jan 12, 1957

By F. H. Wilson, E. W. Palmer

The solid solubility of iron in 2 to 10 pct cupro-nickels increases with temperature and nickel content. Property changes accompanying various heat treatments indicate typical precipitation hardening behavior. Iron content also affects softening temperature and sub-scale formation. These factors, as well as impingement corrosion resistance, influence the optimum iron content of commercial alloys. FOR many years Cu-Ni alloys have been used extensively in the form of tubes, pipes, and plates for the construction of salt-water lines and surface condensers on shipboard and in tidewater power stations. The 30 pct Ni alloy has been considered more resistant to rapidly flowing sea water than alloys of lower nickel content, and has been standard on ships of the U. S. Navy. Some ten years ago, the still better corrosion resistance obtained by modifying the 30 pct Ni alloy with approximately 0.5 pct Fe was recognized, and the iron-bearing alloy rapidly superseded the plain alloy as the standard material for severe service. In 1945, Tracy and Hungerford1 published a study of the effect of iron on the corrosion of various cupro-nickels in sea-salt solutions, and their data indicated that the 10 pct Ni alloy containing about 0.75 pct Fe was equivalent to the 30 pct Ni alloy containing 0.5 pct Fe. This was confirmed by LaQue in discussion of the above paper, and by results in an experimental condenser set up at the Kure Beach marine test station of The International Nickel Co., reported by Freeman and Tracy.&apos; The 10 pct Ni iron-bearing alloy is now being very widely used in applications where the 30 pct Ni iron-bearing alloy was formerly considered standard. While this "substitution" has undoubtedly been stimulated by the present extreme shortage of nickel, it must be emphasized that it involves no loss of service performance, and would have occurred anyway in the course of time, for economic reasons. In view of the increasing use of the 10 pct alloy, it seems desirable to make generally available the results of several investigations of Cu-Ni-Fe alloys carried out in the Metallurgical Research Laboratory of The American Brass Co. in recent years. The present paper, deals with the constitution of these alloys in the copper-rich corner of the system, and with the variations in hardness and tensile properties resulting from the heat treatment of alloys containing various amounts of iron. Most of this work is concerned with alloys containing 10 pct Ni. With over about 0.75 pct fe, the 10 pct Ni alloy is suscep- Alloys Several series of cupro-nickel alloys containing iron were used in these investigations. Most of them were prepared in the laboratory, but two samples of commercially fabricated alloys were included. Series A—Nominally 2 and 5 pct Ni, each with 0 to 1.5 pct Fe. Series B—Nominally 10 pct Ni with 0.1 to 0.4 pct Fe. Series C—Nominally 1.0 pct Ni with 0 to 2 pct Fe. Series D—Nominally 10 pct Ni with 3 to 5 pct Fe. Series E—Nominally 10 pct Ni with 1 and 1.5 pct Fe.

Jan 1, 1953

In the General Alphabetical and Analytical Index of A I M E Publications for the years 1926 through 1935, a complete list of the volumes covered is printed on page 5, but the dates of publication of the volumes are not given Therefore the following information regarding the volumes that were printed without numbers may be useful to users of the Index

Jan 1, 1937

By Roger L. Brockenbrough

Steels available for mine-shaft applications are discussed, and the use of steel linings for round and rectangular shafts is reviewed. For rectangular shafts, frameworks constructed of square or rectangular steel tubes offer advantages. Also, corrugated steel sheeting provides a suitable alternative to timber lagging for spanning between the main shaft supports. For round shafts, self-supporting cylindrical steel liners, with circumferential stiffeners to prevent collapse, have been used to depths up to 6000 ft. Several large-diameter round shafts have been constructed with a concrete lining and an internal framework: of high-strength low-alloy steel tubes. It is concluded that in any new shaft construction steel designs should be investigated as economical alternatives to designs using other materials.

Jan 1, 1976

By R. H. Gautschi, F. C. Langenberg

Rare-earth additions were made to laboratory heats of Type 310 stainless to observe their effect on as-cast ingot structure, nitrogen and sulfur contents, and nonmetallic inclusions. Lanthanum had a grain-refining effect in 30-lb ingots, but results with 200-lb ingots were inconsistent. Cerium, lanthanum, and misch metal lowered the sulfur content when the sulfur exceeded 0.015 pct and the rare-earth addition was greater than 0.1 pct. The rare-eardh content in the metal dropped very rapidly within the first few minutes after the addition. The size, shape, and distribution of nonmetallic inclusions was not changed in 30-lb ingots, but changes were noticed in larger ingots. RARE-earth* additions have been made to austenitic Cr-Ni and Cr-Mn steels to improve their hot workability. The high alloy content of these steels often results in a considerable resistance to deformation and inherent hot shortness at rolling temperatures, particularly in larger ingots. Rare earths in the metallic, oxide, or halide form are usually added to the steel in the ladle after deoxidation although they can be added in the furnace prior to tap or in the molds during teeming. The literature- indicates that the effects of rare-earth treatments on these stainless steels are not consistent, and sometimes even contradictory. Since no mechanism has been presented which satisfactorily accounts for the claimed improvements, the effects of rare earths are a qualitative matter. The work described in this paper was initiated to expand the knowledge of the effects of rare-earth additions on melting variables such as ingot structure, chemical analysis, and nonmetallic inclusions. REVIEW OF LITERATURE Ingot Structure—Rare-earth additions to stainless steels have been reported to cause a change in primary ingot structure in that there are fewer coarse columnar grains. However, the results are inconsistent. While one investigation1 has shown a large reduction in coarse columnar crystals, another2 has been unable to observe this effect, particularly when small ingots were poured. Post and coworkers3 observed ingot structures for a number of years and found that the columnar type of structure is not definitely a cause of any particular trouble in rolling or hammering, provided the alloy is ductile. Knapp and Bolkcom4 found rare-earth additions to be quite effective in preventing grain coarsening in Type 310 stainless steel. Chemical Analysis—Many effects of rare-earth treatment on chemical analysis have been claimed in the literature. Russell5 observed that some sulfur is removed by rare-earth metals, and that a high initial sulfur content improved the efficiency of sulfur removal. Lillieqvist and Mickelson6 report that rare-earth treatment causes sulfur removal in basic open-hearth furnaces, but not in basic lined induction furnaces. Knapp and Bolkcom found no sulfur removal in acid open-hearth and acid electric furnaces, probably because the acid slag can not retain sul-fides. snellmann7 showed that sulfur could be lowered apprecfably with rare-earth additions; however, a sulfur reversion occurred with time. Langenberg and chipman8 studied the reaction CeS(s) = Ce(in Fe) + S(in Fe), and found the solubilit product [%Ce] [%S] equal to (1.5 + 0.5) X 10-3&apos;at 1600°C. Results in 17 Cr-9 Ni stainless were about the same as those in iron. Beaver2 treated chromium-nickel steels with 0.3 pct misch metal and observed some reduction in the oxygen content. He also noted an inconsistent but beneficial effect of rare earths when tramp elements were present in amounts sufficient to cause difficulty in hot working. It is not known whether rare earths reduce the content of the tramp elements or change the form in which these elements appear in the final structure. No quantitative data are available concerning a possible effect of rare-earth treatment on hydrogen and nitrogen contents. However, Schwartzbart and sheehan9 stated that additions of rare earths had no effect on impact properties when the nitrogen content was low (0.006 pct), but served to counteract the adverse effects of high nitrogen content (0.030 pct) on these properties. Knapp and Bolkcom4 analyzed open-hearth heats in the treated and untreated conditions and found the nitrogen content (0.006 pct) to be unaffected. These two results lead to the speculation that rare-earth additions can reduce the nitrogen content to a certain level. Decker and coworkers10 have observed that small amounts of boron or zirconium, picked up from magnesia or zirconia crucibles, increased high-tem-

Jan 1, 1961

By John D. Kalasky, Stephen Krickovic

Adequate ventilation in coal mines depends upon good face control, as well as upon a well designed and properly controlled overall ventilation system. The fundamentals of effective bleeding for provision of good ventilation and control and removal of methane are described. The various mine pillaring systems for which it is both easy and difficult to provide effective bleeder systems are detailed. Bleeders in conjunction with longwall mining are also discussed.

Jan 1, 1974

By George S. Lockwood

Plans are moving ahead toward the July 1965 start-up date for Kaiser Steel Corp.’s new pelletizing plant at its Eagle Mountain, Calif., iron mine. Capacity will be 2 million long tons of pellets containing 65% Fe. A major portion of the output is scheduled for charging into Japanese blast furnaces as the result of a contract to supply Mitsubishi interests with 10.8 million tons of pellets over a six-year period. Kaiser&apos;s concentrating plant at Eagle Mountain plus sintering facilities at Fontana are adequate to meet the requirements of its blast furnaces, which, as a consequence, are not expected to take any substantial quantity of pellets during this period. However, some 200,000 tons of pellets per year is scheduled to be used for the production of special steels and in the open hearths as a substitute for the high-cost ores now being used.

Jan 8, 1964

By Fred W. Stiefel

This paper covers the operation and maintenance of Diesel locomotives underground on a portion of the Delaware River Aqueduct. † This part of the tunnel is 15 miles long, with shafts 14 ft. in diameter spaced about 5 miles apart. These shafts (2, 2a and 3) are 825 ft., 1551 and 840 ft. deep, respectively. The grade of the tunnel is almost level, except for the 12,100 ft. north of shaft 2, which has a grade of 2.31 per cent. The tunnel is circular, 17 to 19 ft. in diameter. It lies at a depth of 400 ft. below sea level, with a maximum overburden of 2400 feet. The tunnel driving was carried on in six headings, using 15 storage-battery locomotives, each of 13 gross tons and having a maximum speed of 8 miles per hour. The longest haul was 3 miles, which proved to be the maximum distance for which storage-battery locomotives could be employed economically for the amount of material to be moved. One locomotive was used for switching cars at each heading, one for switching cars at the bottom of each shaft and one on the main-line haul from the heading to the shaft. The maximum amount of material hoisted in one shaft from two headings when 104 ft. of tunnel was driven in 24 hr. was 1000 cu. yd., or about 2000 tons of rock in place. The total quantity excavated was 750,000 cu. yd. (1,500,000 tons of rock). The tunnel-lining operations using concrete presented a problem of hading a maximum distance of 5 miles in the tunnel. The concrete-placing equipment had a capacity of about 2000 CU. yd., or 4000 tons in 24 hours. Experience had shown that storage-battery equipment could not handle this quantity of material within the time required at the distance of 5 miles. Trolley-locomotive haulage was considered dangerous and expensive, and would cause interference because transmission equipment would be required. Therefore the performance of Diesel locomotives of 160 hp., with a speed of 18 miles per hour, in comparison with that of other types of locomotives, was studied. Choice of Locomotives In deciding upon the type of locomotive to be used for the 5-mile haul, four alternatives were considered, as follows: I. To purchase additional storage-battery locomotives with the necessary batteries over the 6 locomotives and 12 batteries available. 2. To convert the existing battery locomotives to the trolley type. 3. To purchase new trolley locomotives. 4. To purchase Diesel locomotives. Proposition No. i The 90-hp. storage-battery locomotives the (each weighing about 12 tons), when hauling a load of 64 tons, with a drawbar pull of about 1900 lb. on a level track, developed a speed of 8 miles per hour and could make five round trips in 8 hr. with a

Jan 1, 1943

By Fred W. Stiefel

This paper covers the operation and maintenance of Diesel locomotives underground on a portion of the Delaware River Aqueduct. † This part of the tunnel is 15 miles long, with shafts 14 ft. in diameter spaced about 5 miles apart. These shafts (2, 2a and 3) are 825 ft., 1551 and 840 ft. deep, respectively. The grade of the tunnel is almost level, except for the 12,100 ft. north of shaft 2, which has a grade of 2.31 per cent. The tunnel is circular, 17 to 19 ft. in diameter. It lies at a depth of 400 ft. below sea level, with a maximum overburden of 2400 feet. The tunnel driving was carried on in six headings, using 15 storage-battery locomotives, each of 13 gross tons and having a maximum speed of 8 miles per hour. The longest haul was 3 miles, which proved to be the maximum distance for which storage-battery locomotives could be employed economically for the amount of material to be moved. One locomotive was used for switching cars at each heading, one for switching cars at the bottom of each shaft and one on the main-line haul from the heading to the shaft. The maximum amount of material hoisted in one shaft from two headings when 104 ft. of tunnel was driven in 24 hr. was 1000 cu. yd., or about 2000 tons of rock in place. The total quantity excavated was 750,000 cu. yd. (1,500,000 tons of rock). The tunnel-lining operations using concrete presented a problem of hading a maximum distance of 5 miles in the tunnel. The concrete-placing equipment had a capacity of about 2000 CU. yd., or 4000 tons in 24 hours. Experience had shown that storage-battery equipment could not handle this quantity of material within the time required at the distance of 5 miles. Trolley-locomotive haulage was considered dangerous and expensive, and would cause interference because transmission equipment would be required. Therefore the performance of Diesel locomotives of 160 hp., with a speed of 18 miles per hour, in comparison with that of other types of locomotives, was studied. Choice of Locomotives In deciding upon the type of locomotive to be used for the 5-mile haul, four alternatives were considered, as follows: I. To purchase additional storage-battery locomotives with the necessary batteries over the 6 locomotives and 12 batteries available. 2. To convert the existing battery locomotives to the trolley type. 3. To purchase new trolley locomotives. 4. To purchase Diesel locomotives. Proposition No. i The 90-hp. storage-battery locomotives the (each weighing about 12 tons), when hauling a load of 64 tons, with a drawbar pull of about 1900 lb. on a level track, developed a speed of 8 miles per hour and could make five round trips in 8 hr. with a

Jan 1, 1943

By W. B. Heroy

ONLY through the mineral fuels can large amounts of energy be transported to great dlstances and stored for long periods for future use. Coal has the advantages over oil of greater safety of handling and smaller losses in storage. But oil is, in the present stage of technical advancement, the more economical source of liquid fuel for internal-combustion motors. No method for direct use of coal in such motors has been developed that can compete with petroleum products. The automoblle engine and the airplane motor are designed to make the most effective use of gasoline.

Jan 1, 1944

By Henry G. Petrow, Edward S. Porter

MAJOR occurrences of lignite with significant uranium concentrations have been reported in western parts of the Dakotas, especially in Harding County, S.D., and Billings and Slope counties, N.D. Samples containing as much as 2 pct U3O8 were received at the Winchester Laboratory, but those deposits reportedly of major significance have generally contained 2 to 4 lb of uranium per ton of lignite. Most of the uranium appears to be associated with the carbon in the lignite as a urano-organic complex, although in most instances analysis of inorganic material has shown uranium values. Molybdenum is similarly associated with the carbon, and its concentrations generally parallel the uranium. The noncarboniferous material is mainly composed of gypsum, jarosite, bentonite, sandstone, and miscellaneous carbonates and silicates. The heating value of these lignites has been determined as about 3500 Btu on a dry lignite basis. The ash content of lignite has varied widely, the important samples containing 30 to 60 pct ash on a dry lignite basis. Because of the significant upgrading of uranium values obtained by ashing the lignite, and because recovery of uranium from raw lignite presented formidable processing problems, major emphasis at Winchester has been placed on devising methods to recover uranium from lignite calcines. Proper roasting removes the problem of organic fouling of solutions, reduces the size of the leaching plant for an equivalent uranium throughout, and generally provides equal or better acid leaching efficiency with less acid than can be obtained from the raw lignite.

Jan 9, 1957

By F. B. Plummer

THE physical properties of oil-producing sands, such as grain size, porosity, and permeability, are becoming more and more important in petroleum production engineering as oil fields are being repressured and rejuvenated. A number of excellent papers have been published recently on all three of these properties. Faucher, Lewis and Barnes1 give a com-plete survey of the work done through 1932 and contribute also much information on sands that they themselves have examined. Muskat and Botset,2 Wykoff, Botset, Muskat and Reed,3 Hurst,4 and Muskat5 have contributed a great deal to the theory and actual measurement of flow of liquids and gases through porous media. Muskat and Botset have measured the permeabilities of different sands with gases and liquids. They find that the radial is always slightly under the linear permeability. However, in most of the previous experiments small samples of the sand were used, and the method of production of fluid or gas through the sands has not been very close to actual oil-field conditions. In addition, so far as the authors are aware, no measurements of linear and radial permeabilities have been made simultaneously under exactly the same conditions. The multiple permeability apparatus described here is a part of the equipment being acquired by this laboratory for thorough investigation of the physical properties of producing sands. It possesses certain advantages for comparative studies of liquid flow. Additional data and descriptions of other instruments will follow in papers to be written later on. The essential features of the permeability apparatus are as follows:

Jan 1, 1934

By J. A. Harrison

The physical composition of coal and the distribution of its physical constituents will partially determine the efficiency of the process chosen for coal preparation. Distribution and concentration of coal macerals will, to a degree, be controlled by preparation processes. A number of preparation processes have been evaluated to determine this interrelation. These evaluations will help provide information needed for the production of coal that meets definite petrographic composition specifications. etrographic composition and degree of coalifica-tion of coal can determine the choice of cleaning processes and equipment used in coal preparation. The purpose of this paper is to present data on studies of the preparation processes of breakage, sizing, cleaning, and blending and to show the effect coal&apos;s petrographic composition has on these processes. Herrin (No. 6) and Danville (No. 7) Coals from Illinois were used in these tests. Nomenclature used herein is that approved in the Glossary of the International Committee for Coal Petrology,&apos; based primarily on the Stopes-Heerlen system of classification2 and used in coal petrography laboratories throughout the world. BREAKAGE TESTS Breakage tests of Illinois coals related to petrographic composition have been conducted at various times at the Illinois State Geological Survey. These tests have been classified under two headings -impact tests and compression tests. Impact tests, as the name implies, consisted of breaking the coal by a sharp, sudden force. Impact tests were further divided into fall tests and block tests. Compression tests consisted of applying a constant pressure on a piece of coal until the coal fractured.

Jan 1, 1963

By Arthur F. Daily

13.5-1. Placer Deposits-Definitions. Placers are defined for this chapter as unconsolidated deposits of detrital material containing valuable mineral, and placer mining is defined as surface exploitation of placer deposits. Unconsolidated marine deposits containing industrial minerals, such as the very large pebble phosphate beds in Florida, pelletal phosphate beds in the Sechura Desert in northwestern Peru, oyster shell beds occurring at many places, and nodules resting in the sea floor, are not classed herein as placer deposits, though methods commonly used for mining placers may be employed for their exploitation. The natural processes that may form placers range from chemical weathering to stream, marine, and wind action, and combinations thereof, resulting in some degree of concentration of valuable mineral. One or more cycles of erosion and deposition may have occured. In relation to mining, placers include unconsolidated barren or near-barren overburden and underlying weathered bedrock. Placers of any origin subsequently may become drowned by the sea and then partly or entirely covered by marine deposits; or they may become covered with alluvium, eolian deposits, or lava. The mining of placer deposits for valuable mineral content usually is followed immediately by primary concentration using wet (rarely dry) gravity methods, succeeded by secondary concentration employing both gravity and other methods. 13.5-2. Classification of Placers. A fundamental classification of placers according to genetic types follows; some degree of concentration occurs during formation of all except saprolite and some moraines. 1. Saprolite and residual placers, consisting of mineralized rock decomposed in situ principally by chemical weathering; respectively either without change in volume, or slumped because of dissolution of some constitutent.

Jan 1, 1968