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By C. M. Schwerin

It is often necessary to calculate the size of a hoisting-plant required to raise a given quantity of material, either as a preliminary to the detail design of the machinery, or to decide whether machinery on hand or offered by a manufacturer is adapted to the work to be done. The first element of the problem to be determined is the load to be raised. In a mine that is already developed, this is limited by the size of car that can be hoisted out of the mine and that will pass through the underground gangways. If these place no limits on the design, the size of the load will depend on the output desired per day, and on the number of hoists that call be made per day. The latter are fixed by the time required per hoist and the number of hours available for hoisting, after deducting from the working-day the time required for raising and lowering men, sending down supplies, and for the many small delays in handling cars. It must also be decided whether the hoisting is to be done in one shift or in all of them.

Jan 1, 1903

By S. C. Termes, R. L. Wilfong

As part of an effort to provide basic data on the fundamental scientific and engineering principles of minerals beneficiation, the Bureau of Mines is conducting research on the flocculation of mineral fines. This paper presents results of studies using cross-linked starches containing carboxyl, diethanolamine, iminodiacetic acid, and xanthate groups to flocculate hematite, goethite, chromite, manganite, pyrolusite, cuprite, and cassiterite fines. The carboxyl and xanthate derivatives flocculated all minerals except cassiterite; the latter was flocculated by only the diethanolamine derivative. The imlnodiacetic acid derivative flocculated hematite, goethite, chromite, cuprite, and pyrolusite fines. Zeta potential measurements were made to help define the reaction mechanism responsible for flocculation. These measurements indicate that electrostatic attraction probably is not involved, except possibly in the case of the diethanolamine derivative. The separation of hematite from quartz by selective flocculation with chelating crosslinked starches under two pH conditions and with two dispersing agents is described. Best recoveries and grades were found when either the carboxyl or xanthate derivatives was added at the natural pH of the pulp in the absence of a dispersing agent.

Jan 1, 1984

By R. C. Hall

DEVELOPED to grow single crystals of alloys of high hardness and high melting points is a simple but effective apparatus described in this note. Growth from the melt, that is, by the Bridgman technique, hay be applied to metals or alloys which are physically hard as long as no phase transformation occurs on cooling to room temperature. The present apparatus was employed to grow single crystals of the ferromagnetic AI-Fe alloys above 1 wt pct Al and the Si-Fe alloys above 3 wt pct Si. Single Crystal Growth In a simple form, the method for growth of single crystals from the melt requires a molten metal charge in a pointed crucible which is slowly low-ered through a heated zone into a colder zone. Solidification starts at the bottom point and continues up the charge as the crucible is lowered through the heated zone. If a single crystal nucleates at the bottom, one crystal may grow throughout the charge under ideal conditions of slow growth.4,5 The presently developed method of growth was designed so that the chances that more than one crystal would grow were small. The single crystals were growth by the apparatus illustrated in Fig. 1. The charge was in the form

Jan 1, 1958

By Samuel Dolbear

PUBLIC discussions of mine finance in the tech-nical press have been confined mainly to methods of providing funds for the development of pros-pects or other mining operations which have not reached the stage of productivity. The application of modern financing methods to mines which have behind them a successful record of net earnings has, for some reason, been given scant consideration by mine owners and managers. In a few conspicuous cases, such for example as the Anaconda Copper Mining Co., Chile Copper Co., and one or two others, industrial finance has been applied to mining operations on the scale and after the fashion of other operations. When extensions are needed re-course is usually had, however, to the sale of common stock, with the obvious disadvantage of diluting the holdings of every stockholder of record prior to such financing. In some cases, it has been sought to over-come this disadvantage by issuing stock purchase rights to shareholders of record. If the stockholder is in a position to acquire additional stock, he may then pre-serve his interest intact, otherwise he must suffer a dilution of his holding. If he purchases additional stock he is, from one point of view, paying more for his in-terest than he bargained for when he made his original purchase. In many cases development and equipment are paid for out of surplus or current earnings. It is sometimes most difficult to explain to a manager why he can afford to borrow money when funds are available from a sur-plus account. Nevertheless, industrial enterprises with adequate surplus accounts often finance new construc-tion by the issuance of bonds. Such a procedure enables the company to maintain its surplus intact, and to con-tinue the payment of dividends during a temporary period of unusual expenditures.

Jan 2, 1927

By Walter Miller

With returning prosperous conditions in all industries, oil-refinery engineering has found opportunity for the more extensive application of improvements developed during the several years of depression. The year has brought out little of an entirely new nature, but much in wider application of previous worth-while developments. The greatest volume of work done has been in modernizing the distillation and cracking units of existing refineries, particularly by substitution of combination skimming and cracking units for older equipment, and the installation of cracking plants in smaller refineries where formerly only skimming was practiced. A number of entirely new refineries were installed during the year, two of the most important being the 20,000-bbl. refinery by the Atlantic Refining Co., at Atreco, Tex., and a 12,000-bbl. plant by the Wilshire Oil Co., at Norwalk, Calif., these two embodying some of the latest developments in cracking and treating. Total refining capacity for the United States is now reported as being something over 4,000,000 bbl. per day, but a movement is on foot looking to a complete revision of these figures, as experience has indicated not only some overstatement of capacity of equipment but that considerable equipment is included which because of obsolescence and location will probably never be run again. The 3,000,000-bbl. figure which the industry reached during the year's high consuming period required the operation of probably 95 per cent of the country's efficiently usable capacity. Cracking and Polymerization There were no new outstanding developments in the cracking field, progress being made largely in the further refinement of known principles. Improvements in furnace design and operation have been largely in permitting closer control of the heating curve through the cracking-tube system, assisting in more uniform yield and in the lessening of coke deposition, and permitting longer trouble-free operating time as well as reduction in furnace-maintenance cost. Actual operating polymerization capacity has been increased little during the year, but a number of projects have been started, some nearing completion, the production from which will be available during 1937.

Jan 1, 1937

By F. G. Tryon

This paper treats only of the practicability of introducing a standard classification into the records of production and distribution of coal which we try to keep in the Bureau of Mines. From the point of view of gathering and analyzing statistics, the requirements of a satisfactory classification are that it shall be so definite as to eliminate the factor of arbitrary judgment, that it shall be reasonably simple and, finally, and most important, that it shall be understandable to the trade. In other words, to be woven in the statistical record it must be adapted to the raw material which flows in from the 7000-odd mines that produce the coal. The success of any scheme of classification, from the point of view of use, will depend largely on the degree to which it utilizes the accumulated experience of the trade and employs as far as may be possible the accepted trade designations. The experience of the Tidewater Coal Exchange during the war would be an excellent point of departure for a use classification of the coals of the Eastern Appalachians. Although the exchange long since passed out of existence, coal is still quoted and sold by the old pool numbers, and they have shown rather extraordinary vitality. Some years ago, in the Geological Survey, the experiment was tried of getting operators to classify their own coal by offering them a list of standard designations on the annual statistical questionnaire. The results were more amusing than informative. What with the confusion in terminology and the natural temptation to put one's best foot foremost, there was a general tendency to grade up the quality. Floods of semi-bituminous coal flowed in from many sources, millions of tons from districts where not a pound of that quality has ever been produced. The producers of semianthracite in Arkansas almost without exception would report their product as anthracite and their neighbors in the little Paris field, producing a fine blocky house coal averaging about 17 per cent, volatile, would say, "Our coal isn't anthracite; it's a semianthracite." Finally we discontinued the publication of those data as being more misleading than helpful.

Jan 1, 1930

By S. C. Sun, D. R. Mitchell

Experiments show that ores such as tungsten and tin, which slime excessively, can be deslimed and upgraded by ultrasonics. The method proposed depends primarily upon the stratifying and peptizing action caused when high frequency sound waves are propagated upward through ore pulp in a cylinder tube. Stratifying and peptizing are somewhat hindered by the accumulating action, which embodies additional effects of reflection and refraction.

Jun 1, 1956

By Northcutt Ely

The subject of this paper implies three questions: whether regulation is necessary; if so, what sort of regulation is wise; and, finally, by what government the power to regulate is to be exercised. In the year 1937 emphasis falls on the third of those questions. This contrasts with the situation prevailing a dozen years ago, when the question was whether regulation was necessary at all; and with the situation a few months ago, when the third question seemed answered by the Supreme Court decisions on the National Recovery Act, Agricultural Adjustment Act and Guffey Coal Control Act, and by the ratification of the Interstate Oil Compact. It then appeared settled that the State and not the Federal Government possessed the regulatory powers and, granting that conservation measures are a recognized necessity, the problem seemed to be to develop the wisest kind of regulation that the Constitution would permit. Today, by virtue of developments during the first months of 1937, the oil industry is faced again by the question of whether the Federal Government is to have power to control its operations, along with those of the other basic industries. Developments in Governmental Control There have been three recent developments. The dominating one is the President's proposal that he be authorized to increase the size of the Supreme Court to 15 members. The implications of that plan ought to be perfectly plain to the oil industry. This suggestion is made in lieu of offering an amendment to the Constitution, to reverse the Supreme Court decisions mentioned. In those decisions the Court held that production does not constitute commerce, and hence that the Federal power to regulate interstate commerce does not extend to the regulation of production. These holdings were contrary to the Government's contention that the stream of commerce begins in the factory and ends with the consumer and may be regulated at any point from beginning to end. That position was urged in the Government briefs in Amazon Petroleum Co. v. Ryan, defending the petroleum code, and repeated as late as Feb. 10, 1937, in the case of National Labor Relations

Jan 1, 1937

By James C. Fisher

Traditional uranium exploration techniques were utilized and comparatively evaluated in the Front Range, Colorado uranium province. Intense surficial leaching and thick colluvial cover render traditional airborne and ground radioactivity reconnaissance prospecting useless. Radon gas emanometry and sulfur gas emanometry were slightly more effective but the long and short term variations In soil gas emanation rates make it extremely difficult to gain useful information from these systems. The technique judged most useful was Track Etch radon prospecting. The excellent definition of the technique, as well as its repeatability, indicate that it is an ideal prospecting tool for narrow vein-type deposits similar to those of the Front Range, Colorado.

Jan 1, 1976

By D. M. Bondurant

AT the present time, the coal industry is greatly interested in any method or machine that will cut the cost of producing a ton of coal, while at the same time producing a product of quality and grade suitable to the customer. Comparatively new and, as yet, little known, auger mining is proving a profitable method of coal recovery. It may be used for the production of low-cost, high-quality coal with equal success from both the hard-to-mine seams, those with banded impurities and bad roof conditions, and the more easily mined seams as classified according to conventional mining methods. A number of units are now in operation and production information is available that should be of particular interest to coal operators and of general interest to anyone associated with the coal-mining industry. Auger mining refers to coal extraction with large size augers capable of drilling to great depths and having a high capacity. Consideration of the equipment and methods used in drilling an ordinary shot-hole will give a picture of auger mining on a smaller scale. At present, auger mining is used largely for recovery of coal from the highwall after strip mining becomes uneconomical because of the type and the thickness of the overburden which must be moved. Coal augers have many of the advantages of present continuous mining machines, along with many more. The four distinct operations of conventional mining-—cutting, drilling, shooting, and loading— are eliminated and replaced by the combined operation of boring and conveying of the coal. The coal recovery auger is an adaptation of the horizontal rock drill used for drilling shot-holes to shatter and loosen overburden in strip mining operations. During the war the Becker County Sand and Gravel Co. of Summersville, W. Va., experimented with drilling coal with 6 and 9-in. rock augers. The results led to the successive development of the 20, 24, 30 and the 36-in. machines, the latter having appeared in the coal fields within the past six months. Because of the great success of the smaller size

Jan 1, 1952

By P. St. J. Perrott

AN explosive of balanced composition might be expected, on first consideration, to develop maximum propulsive strength.1 This hypoth¬esis is based on the assumption that an excess of oxygen would act simply as an inert material with a consequent lowering of flame temperature, also that a deficiency of oxygen would tend toward incomplete reaction of the combustible materials, thereby preventing development of the full strength of the explosion. Actually, however, it can be shown both theoretically and experimentally that an explosive having a certain oxygen deficiency will develop the greatest propulsive strength. This fact has been known to the technical staffs of explosives manufacturers for many years, but it has not always been recognized by explosives engineers in the field. For example: There is a fairly widespread opinion that the wrapper of a stick of dynamite is merely a container for the explosive and that it plays little if any part in the development of propulsive strength. Actually, it can be shown that the wrapper enters fairly completely into the explosive reaction. In the case of most gelatin dynamites, a given weight of explosive from which the wrappers have been removed will develop considerably less strength than the same weight of explosive plus wrapper, in spite of the fact that the latter combination contains less weight of the actual explosive ingredient. It can also be shown that a cartridge 7/8 in. in diameter may be stronger, weight for

Jan 1, 1928

By Rossiter W. Raymond

(Read at the Wilkes-Barre Meeting, May, 1877.) THE 12th of April, 1877, witnessed the celebration, at Freiberg, Saxony, of an event profoundly important for the ancient mining industry of that district, and full of interest to mining engineers throughout the world-namely, the connection of the famous Roth-

Jan 1, 1878

By W. W. Loo

A REVIEW of the literature on the reduction of cassiterite showed. that scarcely any progressive changes were made in the methods of reducing cassiterite until within the last two decades, and that during that period many improvements in the metallurgy of tin have taken place. Since 1914 the world's consumption of tin has increased considerably, resulting in the exploitation of primary tin deposits such as the Bolivian lode, which has become an important source of tin. On account of the low tin content of Bolivian ore, and the presence of objectionable impurities of the reduced tin, the smelting of this ore and the refining of the tin has changed considerably from the methods formerly used. A comparative study of the methods of smelting cassiterite concentrates suggested that an investigation be planned so as. to determine what factors effect the extraction of tin from its ores by reduction with carbon. The first part of the experimental work was the determination of whether roasted cassiterite concentrates can be reduced by carbon without the use of flux, and the reduced pellets of tin be collected into a single mass separate from the dry gangue residue The second part of the experimental work was a comparison of the effect of variations of the different factors on the smelting of roasted cassiterite concentrates: first, the effect of varying the composition of the slag; second, the effect of varying the amount of reducing agent; third, the effect of varying the relative amount of the resulting slag; and fourth, the effect of different kinds of reducing agents:

Jan 1, 1928

By L. E. Shiffman

This paper describes the operation of two kerosine flotation plants in Alabama for cleaning —10 mesh bituminous coal. One plant treats washer sludge, the other raw coal. Data on capacity efficiency and capital and operating costs is given. Methods for increasing cell capacity are discussed. IN cleaning coal it has long been recognized that methods which give excellent results for the coarser sizes may give poor or even no cleaning for the finer sizes. Effective cleaning of the fines, therefore, is usually a separate and distinct problem. For many years the problem of fines was considered of relatively minor importance. Now there is growing interest in methods of cleaning the fine sizes of coal because: 1. There are more fines. Increasing mechanization and the adoption of full seam mining methods have resulted in the production of a greater percentage of smaller particles than were produced by hand loading methods. 2. The fines have deteriorated in quality. The same causes that have led to increased quantity have also operated to decrease quality through greater contamination with slate, rock, and other diluents. 3. The fines have become more valuable. When coal was comparatively cheap, loss of the finer sizes was tolerated but, with the rapid increase in the cost of mining coal, it has become imperative that the maximum amount of clean coal be recovered from the mixture of coal and rock delivered to the tipple. 4. In many cases, the fines have become a stream pollution problem. Increasing governmental activity and legislation to prevent stream pollution often have made it necessary to retain the fine material which formerly was permitted to escape with the washer effluent into flowing streams. The Sloss-Sheffield Steel and Iron Co. operates four coal mines, all within a 20-mile radius of Birmingham, Ala., with a total annual production of 1,-250,000 tons of washed coal. Three of these mines are in the Mary Lee seam and one in the Jefferson seam. Although some steam and domestic coals are produced, the major portion of the coal is used to make coke for blast furnace operation. Fine coal is desirable for coking, and all the coal so used by Sloss is crushed to 1/4 in. Therefore, there is no problem of an outlet for even the finest sizes of coal. Since the coal is used for metallurgical purposes, low ash is of greater importance than would be the case if it were used for steam generation or domestic heating. Based on present blast furnace practice at Sloss, it is calculated that each percentage of ash in the coal carries a penalty of $0.22 per ton of coal. Thus there is a considerable margin for operating costs in a fine coal cleaning method that will result in materially lowering the ash content of the cleaned coal. Development of Fine Coal Cleaning Problem In 1942 Sloss reopened its Bessie mine and constructed at this location a new preparation plant to clean 11/4 in. x 0 coal from the Mary Lee seam.

Jan 1, 1951

By R. Gibson, F. S. Turneaure

The tin deposit of Monserrat, Bolivia, consists of one major vein 1600 m in length. The ore is unusual because of the notable quantity of teallite, even though cassiterite is the principal tin mineral. The deposit, formed at shallow depth under a wide range in temperature, may be classed as xenothermal. Polished sections reveal a complex history of replacement, with low-temperature minerals deposited before high-temperature minerals. THE Monserrat mine1'2 of the Compania Minera Monserrat is located 11 km east of Callipampa, a station on the Antofagasta and Bolivia Railway some 55 km south of Oruro. The mine lies in a group of low hills on the east slope of a broad valley of northerly trend. The valley is separated from the altiplano to the west by a prominent ridge that rises several hundred meters above the surrounding country (fig. 1). Callipampa is situated a short distance west of the ridge, near the east margin of the altiplano. The elevation at Callipampa is 3700 m and at the mine 4100 m. Monserrat is near the northeast limit of what may be called the Poopo-Pazna district, an area of northwesterly trend about 25 km in length and 15 km in width. The district includes the tin-silver prospects of Poopo to the north, the zinc-tin deposits of Salvador to the southwest, and the tin-tourmaline veins of Avicaya to the south. Along the prominent ridge already mentioned, which forms the western limit of the district, there are several tin and antimony prospects including the Trinacria mine, which is famous for its fine specimens of cylindrite. Although the principal ore mineral is cassiterite, the tin deposit of Monserrat contains an unusual amount of teallite. Cassiterite occurs in part as a finely granular mixture with sulphides of iron and zinc and in part as needle tin of late hypogene age. The regional structure is dominated by broad folds typical of the Andes of Central Bolivia and similar to those of the Llallagua district. The area adjacent to the Monserrat mine is underlain by thin-bedded shale somewhat variable in color but predominantly dark grey to black. The beds strike northwest and dip at low angles southwest, forming part of the northeast limb of a major syncline. A resistant sandstone formation, which underlies the black shale, crops out along a ridge east of the mine and also accounts for the high ridge to the west that was previously mentioned. No igneous rock of any kind is found at Monserrat. The nearest intrusive bodies known are the irregular dikes and masses of quartz porphyry at Avicaya about 10 km to the south. Mine Workings The Monserrat property includes one main vein, which can be followed on the surface for 1600 m, and two or three branch veins of distinctly minor importance. The principal haulage tunnel, referred to as the San Carlos adit or level III, extends northeasterly for 1700 m, following the main vein throughout most of this distance. Above the adit, there are

Jan 1, 1951

By L. E. Shiffman

This paper describes the operation of two kerosine flotation plants in Alabama for cleaning —10 mesh bituminous coal. One plant treats washer sludge, the other raw coal. Data on capacity efficiency and capital and operating costs is given. Methods for increasing cell capacity are discussed. IN cleaning coal it has long been recognized that methods which give excellent results for the coarser sizes may give poor or even no cleaning for the finer sizes. Effective cleaning of the fines, therefore, is usually a separate and distinct problem. For many years the problem of fines was considered of relatively minor importance. Now there is growing interest in methods of cleaning the fine sizes of coal because: 1. There are more fines. Increasing mechanization and the adoption of full seam mining methods have resulted in the production of a greater percentage of smaller particles than were produced by hand loading methods. 2. The fines have deteriorated in quality. The same causes that have led to increased quantity have also operated to decrease quality through greater contamination with slate, rock, and other diluents. 3. The fines have become more valuable. When coal was comparatively cheap, loss of the finer sizes was tolerated but, with the rapid increase in the cost of mining coal, it has become imperative that the maximum amount of clean coal be recovered from the mixture of coal and rock delivered to the tipple. 4. In many cases, the fines have become a stream pollution problem. Increasing governmental activity and legislation to prevent stream pollution often have made it necessary to retain the fine material which formerly was permitted to escape with the washer effluent into flowing streams. The Sloss-Sheffield Steel and Iron Co. operates four coal mines, all within a 20-mile radius of Birmingham, Ala., with a total annual production of 1,-250,000 tons of washed coal. Three of these mines are in the Mary Lee seam and one in the Jefferson seam. Although some steam and domestic coals are produced, the major portion of the coal is used to make coke for blast furnace operation. Fine coal is desirable for coking, and all the coal so used by Sloss is crushed to 1/4 in. Therefore, there is no problem of an outlet for even the finest sizes of coal. Since the coal is used for metallurgical purposes, low ash is of greater importance than would be the case if it were used for steam generation or domestic heating. Based on present blast furnace practice at Sloss, it is calculated that each percentage of ash in the coal carries a penalty of $0.22 per ton of coal. Thus there is a considerable margin for operating costs in a fine coal cleaning method that will result in materially lowering the ash content of the cleaned coal. Development of Fine Coal Cleaning Problem In 1942 Sloss reopened its Bessie mine and constructed at this location a new preparation plant to clean 11/4 in. x 0 coal from the Mary Lee seam.

Jan 1, 1951

By F. S. Turneaure, R. Gibson

The tin deposit of Monserrat, Bolivia, consists of one major vein 1600 m in length. The ore is unusual because of the notable quantity of teallite, even though cassiterite is the principal tin mineral. The deposit, formed at shallow depth under a wide range in temperature, may be classed as xenothermal. Polished sections reveal a complex history of replacement, with low-temperature minerals deposited before high-temperature minerals. THE Monserrat mine1'2 of the Compania Minera Monserrat is located 11 km east of Callipampa, a station on the Antofagasta and Bolivia Railway some 55 km south of Oruro. The mine lies in a group of low hills on the east slope of a broad valley of northerly trend. The valley is separated from the altiplano to the west by a prominent ridge that rises several hundred meters above the surrounding country (fig. 1). Callipampa is situated a short distance west of the ridge, near the east margin of the altiplano. The elevation at Callipampa is 3700 m and at the mine 4100 m. Monserrat is near the northeast limit of what may be called the Poopo-Pazna district, an area of northwesterly trend about 25 km in length and 15 km in width. The district includes the tin-silver prospects of Poopo to the north, the zinc-tin deposits of Salvador to the southwest, and the tin-tourmaline veins of Avicaya to the south. Along the prominent ridge already mentioned, which forms the western limit of the district, there are several tin and antimony prospects including the Trinacria mine, which is famous for its fine specimens of cylindrite. Although the principal ore mineral is cassiterite, the tin deposit of Monserrat contains an unusual amount of teallite. Cassiterite occurs in part as a finely granular mixture with sulphides of iron and zinc and in part as needle tin of late hypogene age. The regional structure is dominated by broad folds typical of the Andes of Central Bolivia and similar to those of the Llallagua district. The area adjacent to the Monserrat mine is underlain by thin-bedded shale somewhat variable in color but predominantly dark grey to black. The beds strike northwest and dip at low angles southwest, forming part of the northeast limb of a major syncline. A resistant sandstone formation, which underlies the black shale, crops out along a ridge east of the mine and also accounts for the high ridge to the west that was previously mentioned. No igneous rock of any kind is found at Monserrat. The nearest intrusive bodies known are the irregular dikes and masses of quartz porphyry at Avicaya about 10 km to the south. Mine Workings The Monserrat property includes one main vein, which can be followed on the surface for 1600 m, and two or three branch veins of distinctly minor importance. The principal haulage tunnel, referred to as the San Carlos adit or level III, extends northeasterly for 1700 m, following the main vein throughout most of this distance. Above the adit, there are

Jan 1, 1951

By V. F. Parry, E. O. Wagner

This paper summarizes investigations during 1949 on three pilot plants for drying low-rank fine coal by entrapment in hot gases. Detailed operating results on processing seven coals having moisture ranging from 24 to 62 pet, formulas and data for calculating performance of large units, and general conclusions on the problem of drying fine coal are presented. THIS paper presents a summary of investigations by the Coal Branch of the Bureau of Mines during 1949 on the removal of internal moisture from low-rank coals by processing them in the entrained and fluidized state. A paper on this subject, giving a summary of the early work, was presented at the 1949 AIME annual meeting1 and gave a the- oretical discussion of the time and heat required to dry various sizes of low-rank coal. The investigations on two pilot plants were presented in the foregoing paper. During 1949, three additional pilot plants were built to study phases of the drying problem and to investigate different techniques of handling fine coal in the entrained and fluidized state. The present paper gives operating data on the new units and presents detailed data on the drying of seven coals having bed moisture ranging from 62 to 24 pct. The problem of removing surface moisture from fine coal is principally one of heat exchange and dispersion of the coal particles so that heat can reach the liquid moisture to permit evaporation, and it does not involve the factors of size and time of contact to any great extent. If enough heat can reach the surface of the particles at temperatures higher than 250°F, moisture evaporates almost instantly, and the factors of time and size are of secondary importance compared with the factors of heat balance and dispersion of the coal. Therefore, it does not appear to be necessary to employ a fluidized bed when removing surface moisture, and the most efficient process would be one in which the coal particles are entrained in a hot gas stream of optimum temperature traveling at a velocity that causes the particles to disperse into a low-density phase. When low-rank coals are dried, the fluidized bed is necessary to provide control of time of contact. This is done by adjusting the superficial velocity which controls the density or dispersion of the particles. The density of beds having fluidized properties suitable for drying low-rank coals appears to range from about 5 up to about 15 lb per cu ft. When the density is below 5 lb per cu ft, which represents a low-density phase, optimum conditions for removal of surface moisture should be found, and this requires superficial velocities of about 15 fps. The problem of removing bed moisture from low-rank coals involves consideration of size of coal, temperature, mass flow, heat balance, pressure, time of contact, and method of dispersing the coal in the heating mediums. The experimental work presented here gives data on these factors. Coal sizes up to 1/2 in. x 0 were dried with hot gases having initial temperatures ranging from 1900° to 2400°F. Coal

Jan 1, 1951

By Edward H. Robie

SUBJECT to formal Board approval in September, AIME dues will continue indefinitely at the present scale of $20 for Members and Associate Members; and $12 for Junior Members for the first six years of such membership, thereafter $17. That is the wish of the Board of Directors and the will of the membership, as expressed in the recent referendum. Though the official returns, as reported by the tellers, are not available as this is written, the data are sufficiently complete to give the results to the nearest percent. The total vote was approximately 93 pct for continuance of the present scale. Metals Branch members voted about 94 pet for continuance; Mining Branch members slightly less than that; and Petroleum Branch members about 91 pct. As in the referendum of 1949, there was no particular difference of opinion on the question of dues as between the three Branches. The percentage of ballots returned was about 61 pct, only slightly more than in the 1949 referendum. But the affirmative vote was much greater, 93 pct against 78 pet in the earlier referendum. Looked at another way, a majority of those to whom ballots were sent, 56 pct, voted to continue the present scale of dues, whereas only 46 1/2 pct of those canvassed voted to raise the dues in the previous referendum. But approximately 600 , members expressed their opinion that the dues should go back to $15 for Members and Associate Members and to $10 and $15 for Junior Members. This is a substantial group of members who either do not think they are getting their money's worth from AIME membership, or believe that a more businesslike conduct of Institute affairs should provide current services at less cost, or believe that more service is being provided for their dues than they need. As to the first point, it is probable that some members are not getting their money's worth. They perhaps have only a fringe interest in. AIME activities, or they do not or cannot participate in such activities at the Local Section, divisional, or national level, so that all they get out of the Institute is the monthly journal, which they do not have time to read. If they did read it intelligently, and acted upon the professional information thus gained, it is difficult to understand how one or more ideas cannot be gained that would be worth $20 to them professionally. But the 600 members who want lower dues offer a challenge to the Directors and to the staff to do a better job; to make Institute membership so rewarding that every. member will be thoroughly satisfied. Twenty 1935 to 1939 dollars are worth only $11.60 now, according to the latest government data, but that makes it all the more necessary for us all to appraise the value of what we buy. To the 93 pct of Institute members who expressed a vote of confidence, so to speak, the staff, and we feel sure the Directors as well, are most appreciative and thankful.

Jan 1, 1952

• Pellets of concentrated iron ore have been smelted in the blast furnace by Armco and the results proved satisfactory. Various percentages of pellet burdens were tried and it has been found that charges up to 70 pct pellets are workable. •In the reorganization of the Department of the Interior, two new assistant secretaries were appointed and the work divided between the four assistant secretaries. C. Girard Davidson will head a division of mineral resources including the Bureau of Mines, Geological Survey, Division of Oil and Gas and Division of Geography. •Germanium, one of the rarest of metals and a wartime strategic material, has been discovered almost in the shadow of the Capitol. The only catch is that the scattered nature of the deposits makes profitable recovery extremely doubtful. Nevertheless, experts have tabbed the concentration in the District of Columbia area the world's second richest known concentration of the element. • Cakes of mica, weighing up to 500 lb, have been formed at the Colorado School of Mines by a new "cool hearth" method. The process avoids use of crucibles and contains the molten mica in a basin of unmelted raw mixture from which the melt was derived. Crystallization takes place in this melting basin which forms a center pool surrounded by a solid cool mass of the unmelted raw mixture. • William 1. Baxter, of the International Economic Research Bureau, predicts a period of deflation because of war-essential restrictions on consumer credit and materials use. He stated; "the recent prosperity was based mainly on the sales boom in autos, homes, and household accessories." •Two subsidiaries of United States Steel have decided to build four new ships immediately to augment iron ore and limestone carrying capacity on the Great Lakes to meet demands created by the national defense emergency. •The Norfolk and Western Railway is making a complete change over to coal to drive its locomotives. •A national roster of scientific personnel similar to the one used in the last war will be established by the Office of Education, by agreement with the National Security Resources Board. The new unit, the National Scientific Register Project, will make studies of the Nation's scientific manpower supply and recommend steps to increase the numbers of skilled personnel where needed. •National Lead Co. will start construction immediately of new facilities at St. Louis, Mo., for production of titanium pigments for paints. Producers of titanium pigments have been under considerable pressure to meet all demands from paint manufacturers, particularly for titanium dioxide. •The basic criteria for deferment of reservists in civilian occupations are (1) the Department of Labor List of Critical Occupations, and (2) the Department of Commerce List of Essential Activities, both of which were announced Aug. 3. Fundamentally, the reservist deferred must be engaged in a critical occupation which is necessary to a highly essential activity, and he will be deferred only until he can be satisfactorily replaced in that occupation. A delay in call to active duty, it was emphasized, may not be considered as an indefinite exemption from military service.

Jan 9, 1950