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By Arthur A. Center

HIGH GRADE zinc stocks were reported short early in 1943, but not Prime Western. Maximum production of High Grade was expected to be reached before the middle of the year, and demands of new brass mills were to take all of the increase. In February three premiums (A, B, C) of 2 3/4c. per lb. of zinc in ore were announced to encourage production from high-cost mines, the number of premiums being in proportion to estimates of ore-production costs.

Jan 1, 1944

By D. C. Hilty

C. E. SIMS*—This is a most interesting and important paper. It is important from two standpoints. First, it has as-spects of being highly accurate and therefore extremely useful to the operating man in showing how far he can go in oxidizing carbon from a steel bath while retaining chromium and the effect of temperature on this limit. Fig 5 is undoubtedly the highlight of the paper, and in checking it against available data, it seems capable of predicting actual results. The other important aspect is the apparently significant fact that reactions within a steel bath, such as between carbon and an oxide, are homogeneous reactions which do not require equilibrium with an external phase. In this case, it seems obvious that the reaction and the equilibrium established were between dissolved carbon (or carbide) and dissolved CrO. The classic reaction which requires equilibrium with solid Cr2O3, did not fit the data. It was recognition of this principle that made Fig 5 possible. G. R. FITTERER*—It might be in assuming the CrO is dissolved in the metal that you are actually approaching the correct factor for activity. If that is true and if the percentages that were used represent an equilibrium constant, this would mean, in effect, that the minimum temperature at which chromium would be reduced by an equivalent percentage of carbon would be about 2400°F from your equation. I believe that is in line with my experience particularly if you deal only with low percentages. J. CHIPMAN†—The author in discussing the equilibrium of the reaction offers two choices of explanation. One postulates an effect of chromium on the activity coefficient of carbon; it would require perhaps more data than are available to us at the present time to test this thoroughly. The other postulate which he offers is a reaction with CrO. This explanation is consistent with physical and chemical principles provided that a solid phase CrO is present, and that is essentially what he is postulating. If that oxide were present one would expect and, I think, almost require the kind of results that he obtained. The weakness of that postulate lies in the lack of confirmatory evidence regarding the presence of solid CrO as such. This should offer an interesting subject for further study. It seems a pity that the theoretical arguments revolving around CrO should have obscured for a moment the very real excellence of this paper. E. CARTER*—I think there is a problem that presents itself in practical application where the metal temperature is from 3200 to 3300 and the temperature desired in pouring is considerably less. B. M. LARSEN†—I get the impression from some of the work that was done earlier that there is probably a localized zone of high temperature at the slag metal interface which effects the removal of the carbon. Without that I wonder if the effect is possible to have a localized superheat and an equilibrium there favorable to low carbon content and

Jan 1, 1950

By Henry E. Colton

NeaR the town of Christiansburg, Va., occurs a singular feature in topographical as well as geological structure, which may be said to have an important bearing on a large area to the southwest. The great water-shed ridge, which divides the waters flowing into the St. Lawrence from those flowing into the Atlantic ocean, coming southwestward, forms all of what was the boundary of Maine as agreed upon by the treaty of 1783, and a part of the present boundary, all of the northern New Hampshire boundary, and entering Vermont, continues south of Lake George. Passing irregularly through New York, it enters Pennsylvania, and there bifurcating, sends one prong to the west as a divide between the waters of the lakes and the Ohio, while the other becomes the steady, regular ridge which gave it the name of Alleghany, and thus passes on southwestward through Virginia. At no point has it ever been the geological divide. Its course, commencing in the Archean rocks, has passed through nearly every series of formation, and comes into Virginia in the Carboniferous strata. The geological divide—the line between the fossiliferous and the non-fossiliferous rocks—lies, in Canada, to the west of it, but from New York south into Virginia is far to the east. Reference to Dr. Hitchcock'k map will show this. But at the locality noted these positions are changed; the water-divide becomes the eastern chain, and the geological divide is the western, returning, it may be said, to the positions occupied in the region where they originated. These relations are shown on the large map accompanying the present paper. For several miles, the track of the Norfolk and Western Railroad

Jan 1, 1888

By J. F. Lewis

Much has been written on this great engineering work, principally from the civil engineer's stand-point. In presenting the subject to the Institute, it seems necessary to include something of geology as well as engineering. In this case, it is particularly the glacial and post-glacial periods with which we are concerned; for it has been clearly proved that the canal recently excavated has not for the first time opened the Des Plaines valley for drainage away from Lake Michigan, and that this valley, as well as the site of this city, is very closely connected with the processes and effects of the ice period. We have simply renewed a channel and a drainage direction which formerly existed. As the days of deep water-ways for commercial purposes are fast approaching, engineers may find the consideration of ancient topography and geologic changes highly useful. For what I may say on this subject I am greatly indebted to Mr. Ossian Guthrie, who has made an earnest study of glacial geology and labored especially to decipher the records of its history in this region. * Chicago is situated in the track of one of four great glacial ice-streams that swept down from the North: one moving due South from Marquette and entering the Illinois valley at Ottawa; one through the Lake Michigan valley, entering the Illinois valley near Lemont; one from Saginaw Bay diagonally across the States of Michigan and Iadiana, entering through

Jan 1, 1898

By David E. Hyatt

The chemical attributes of cyanides have long been exploited in ore pro- cessing schemes for the recovery of copper, molybdenum, gold, silver, and other metal values. Blast furnacing operations are significant unintentional producers of cyanides which find their way into process waters. Many of the more than 20,000 electroplating facilities in the United States utilize cyanide plating baths and generate cyanide containing wastes. As social, political, and economic pressures for water quality attainment, maintenance, and preservation grow, the requirements for the development of treatment technology to control cyanide levels in wastewater become increasingly apparent. Just as the chemistry of the cyanide ion 1s an integral part of its industrial applicability, so must this chemistry be a fundamental part of any decomposition or removal technology used to control its level in effluent or recycled waters. The complexity of this chemistry is substantial and it cannot be considered in a superficial or cursory manner if control system design is to be both efficient and reliable.

Jan 1, 1975

By M. R. Geer, H. F. Yancey

John Grifien (Pittsburgh)—I wish to congratulate the authors on this paper, which, I am sure, will promote a clearer conception of the various criteria which have been advanced as measures of coal-cleaning performance. Their clear descriptions of the more important criteria that have been advanced and explanations of their meaning and application have been sorely needed and, if widely promulgated and followed, should remove much of the confusion which, heretofore, has been evident. I suggest that much of this confusion has also arisen from lack of common agreement as to the exact meaning of the words and terms used in our discussions of this subject. I am sure I have been equally guilty in this respect and suggest it is time that we select a committee to study vocabulary as well as criteria, so that common understanding and agreement can be had. Thus, I suggest, that the title of this paper should have used the words "coal-cleaning performance" and not "coal-washery performance." My understanding is that "washery" refers to a complete plant and it has additional functions to that of coal-cleaning, such as control of size, moisture, etc. Also, I do not agree with the authors that the formulas given in their paper, the Fraser and Yancey formulas, are necessarily the only ones that can be called efficiency formulas. When a dictionary is consulted one realizes that the words "efficiency" and "efficient" have not precise meanings but only very general ones and must be further defined for each particular use, if they are to have any precise meaning. To my mind, the first of the Fraser and Yancey formulas given should never be used as expressing "efficiency" alone but only by the fuller phrase which truly expresses the kind of efficiency it states, which is "coal recovery efficiency." For complete clarity we then need only define "coal" for the particular circumstances under which the formula is used. This would recognize the fact, fully explained by the authors, that the limits in coal qualities imposed by the market have imposed a factor—and a variable factor—which has influenced any answer obtained by this formula. Such a procedure makes it entirely practical and logical to use the values of any of the qualities of coal—ash, sulphur, phosphorus, specific gravity—or a combination of them to define what is coal for that particular use of the formula. Further, it is clear to me that the criteria to be used must be dictated by the objective in view and the use for which the data are obtained. The authors clearly point out that the Fraser and Yancey coal-recovery efficiency formula is influenced by three factors, "one is determined by the coal, one is dictated by market or use conditions, and one is an inherent characteristic of the cleaning unit itself." The formula which uses the inverse of misplaced material as a measure of efficiency is also a coal recovery efficiency formula and is influenced in like manner by these three factors. As the authors point out, both are useless in obtaining data which enables a direct and valid comparison of the performance of a given cleaning unit on two coals where the other two factors vary or of the performance of two or more cleaning units of different types unless the values of the other two factors are identical. Much of the confusion in our discussions of and literature on coal cleaning has come from failure to understand clearly this fact. Many such comparisons have been made from which erroneous conclusions have been drawn. I am, therefore, particularly glad to see the authors' emphasis on 4?-1e criteria which indicate the "sharpness of separation. I feel that these are the essential criteria

Jan 1, 1952

By C. S. Smith

The partial persistence of grain size and grain shape on melting and resolidifying crystalline substances, as well as the general effects of pre-solidifi-cation and of superheating on nuclea-tion rate, have been attributed to the presence in the liquid of crystalline impurities bearing some structural relation to the principal solid and hence capable of serving as nuclei for its crystallization. That such lattice matching does sometimes occur is well established, but it is surely improbable that a compound possessing both high-temperature stability and the requisite structural similarity should be naturally available in almost every system. It is now suggested that a mechanism for producing appropriate nuclei exists in the crystallization of all but absolutely pure substances. Impurities can he of many kinds. Some will give rise to compounds that are less soluble in the solid crystal than in the liquid. A . crystal forming from a melt or solution containing these will be supersaturated in some degree, and the foreign atoms will commence to segregate during or after solidification. They do not necessarily form pure, unstrained, crystals of the precipitating compound with its normal composition and structure. Generally—at least in the metallurgical examples that have been most studied —the first recognizable nuclei have lattice coherency with the surrounding matrix and have practically the same crystal structure and lattice spacing as the material in which they form, differ- ing only in composition. An extremely thin oxide layer formed under appropriate conditions on or in a solid metal will tend to be coherent with the metal lattice, and the first few atom layers of the oxide in contact with the metal will differ in both composition and structure from massive crystalliue oxide. It will resemble the metal more closely than the oxide. If it did not subsequently change on melting, such an oxide film would constitute an almost perfect "template" or two-dimensional matrix to hold a few atoms of the primary metal in the exact array needed to form a nucleus for solidification. Any precipitating material will adopt the correct spacing over a few atom diameters, and with appropriate substitution of other atoms of the correct sizes a precipitate can match the parent lattice over large areas of cohererlce without excessive strain. In metals, the componentsof a host of oxides, silicides, borides, nitrides, carbides, sulphides, and other compounds are always present in minute amounts. Some of these will be eliminated because of extreme insolubility in the liquid, while others will remain soluble in the solid; occasionally, however, particles will be formed in the solid by coherent precipitation—not of pure substances, but of whatever assortment of atoms best satisfies the joint requirements of availability, affinity, and appropriate average atom size. Of these, many will disappear on melting, but a few will persist unmelted as little rafts of complex composition, maintaining in the liquid a surface of the exact geometry needed to nucleate the solid on subsequent cooling. Their number and size distribution will determine the resulting grain size; the dimensions of the largest will determine the degree of undercooling that can occur before solidification commences. A similar process may operate in the case of phase transformations in solids. The coherent precipitation of supersaturated minor constituents in a low-temperature phase should facilitate the nucleation of this phase on subsequent cooling after transforming into another phase at higher temperatures. At first sight this hypothesis may seem little different from the older ones. It should therefore be emphasized that it does not depend on chance to provide the right compound to form a nucleus, but postulates that every crystal, containing minute amourlts of any of a wide range of impurities, automatically engenders particles having the correct surface structure to serve as nuclei for subsequent solidification. It could operate in any system, metallic, organic, or inorganic. The suggested mechanism is closely analogous to the production of antibodies from antigens in living organisms—indeed, it was a description of the matrix theory of this process that suggested to the writer its crystalline analogue.

Jan 1, 1950

By A. L. Holley

Those who are familiar with working gas furnaces will perhaps admit that the ordinary producer is the least satisfactory feature of the- whole system, chiefly by reason of its great waste of fuel, both above and below the fire. The waste of fuel in cleaning the fire has not, as fdr as I am aware, been carefully measured ; it has been roughly estimated at various works as averaging twenty per cent. to twenty-five per cent. The coke that falls into the ash-pit is largely mixed, if not stuck together with clinker; when this coke is not recovered and utilized (and where coal is cheap it does not pay to recover it), the waste is certainly as high as above estimated. Cleaning a fire on a grate (especially a fire of dirty coal, like much of our Western coal), by inserting a few temporary grate-bars, then withdrawing the regular grate-bars and letting the whole lower part of the fire tumble into the ash-pit, must necessarily be wasteful of fuel, but it has been found to be the most practical system. The fire under a boiler should be thin, to insure perfect combustion; hence it may be moved from one side to the other, so that .the clinker and ashes may be uncovered and removed. But a producer fire should be so thick that carbonic oxide only shall rise from it; a thick fire cannot be thus manipulated. In several of the French works the ordinary producer without grates is employed ; the whole body of the fire rests on the floor of the ash-pit. It did not seem to me that less fuel was wasted here than with grates in cleaning fires. The bottom layer of the fire had to be drawn out with hooks, and there was nothing to prevent much coke from coming away with the clinker and ash. A producer shaped like a cupola furnace has many advantages, but if grates are employed the waste of coke in cleaning is not lessened. But the waste at the bottom of the fire is only a part of the waste in the ordinary producer. Mr. Emmerton, chemist to the Juliet Iron and Steel Company, has lately made a number of gas analyses from the producers of that company, worked with impure Illinois

Jan 1, 1880

By Carl Thieme

INDUSTRIAL specialization has rapidly created a demand for new and better alloys. A more thorough understanding of the requirements of specific industries and the discovery of processes by which it has been made possible to utilize certain metallic elements in larger quantities, together with greater purity in most virgin metals, has resulted in a great increase in the number and variety of alloys. This increase in the number of elements entering into non-ferrous alloy manufacture has increased the contamination in secondary metals, as received by the smelter. In order to successfully refine scrap of a much more complex nature it has been necessary for the smelter to install new equipment and to constantly search for new methods of refining as well as to improve the methods already in use. In some instances it is largely responsible for specialization in the secondary metal industry. It is usually necessary to remove the contaminating impurities in scrap or eliminate to a degree not objectionable, no matter how introduced. In order to know what metals or elements are of an objectionable nature, the smelter must make a study of the effect of single elements and combinations of elements on many of the physical and mechanical properties, such as strength, ductility, color, hardness, casting soundness, etc. The smelter of secondary metals must be able to utilize scrap materials of all kinds, for, sooner or later, most fabricated metal parts and the waste products formed during the process of manufacture find their way to the smelter. In addition, the smelter, in contracting for salvaged material from the producer, gets some undesirable and unusual materials. The value of secondary metals and the importance of their recovery has increased in recent years and it is no longer sufficient to recover the base metal only, such as copper from copper-bearing material, but it is essential that other elements present be recovered and converted into useful form.

Jan 1, 1928

By J. E. Tobey

UNQUESTIONABLY, manufactured gas will stage a comeback of such huge proportions as to dwarf its previous history. Timing will depend on two things: the diminishing supply of natural gas and the perfecting of processes for large-scale production of high-Btu gas from, coal. What the timing will be, and how soon the new era will begin for manufactured gas, no one knows. It may be just around the corner and it may be several years, but it is certain to come. It will depend on economic changes, and any major world upheaval might accelerate it tremendously. Supplemental gas for pipelines will come no doubt from two sources at least: (1) synthetic-fuel plants of the coal-chemical group, which produce chemicals and liquid fuels with a tail gas high in methane as a by-product; and (2) large-scale gasification plants, which will produce high-Btu gas entirely or as a major product with chemicals and liquid fuels as by-products. There is important activity at the present time, in the development of new processes and the improvement of those now in existence. The first large-scale gasification plants of the second category probably will be strategically located in the coal fields on or near the long-distance transmission gas lines, and these plants probably will operate jointly with large natural gas storage fields. Inasmuch as virtually all the major gas-transmission lines cross one or more coal fields, such locations will not be difficult to find. It will be a practical necessity to produce a high-Btu gas -that is, 750 to 1000 Btu-in order to maintain the capacity of the main transmission lines and local city distribution systems and further to eliminate the problem of appliance changeovers in the cities. If gasification plants on a medium or smaller scale prove to be economical, local gas utilities no doubt will consider .the construction of such plants to supplement their supply of natural gas. If low-temperature distillation processes like those now being developed by the Pittsburgh Consolidation Coal Co. are successful, and there is reason to believe that they will be, utilities that supply both gas and electricity to communities would find this method particularly attractive, as they could burn the char product directly under power boilers, thereby minimizing thermal

Jan 1, 1953

By James E. York

At a meeting of the American Society for Testing Materials at Atlantic City, June, 1908, Dr. C. B. Dudley, in his presiden-tial address,' showed the vital necessity of not only making a steel rail as good as in the past, but of making it considerably better in order to meet the present and prospective requiremeuts of railroads. Doctor Dudley requested the co-operation of all who from personal experience could give information that would result in bringing about the production of a steel rail that could be relied upon to meet the present requirements. I have had considerable experience in the practical manufacture of steel of almost every grade, during the past 40 years, and I shall suggest changes that will bring about the results desired. Doctor Dudley has had a long experience as chemical and metallurgical expert for the Pennsylvania railroad, but he frankly admits that up to the present time both he and other metallurgical authorities lack the practical knowledge of steel-making that is necessary to state correctly the reasons for the unreliability of the steel rails now produced. The necessity is self-evident for more positive practical knowledge on the part of these experts of what is possible and what is impossible regarding the practical manufacturing of steel rails from the ingot to the finished product. Chemical knowledge in steel-making is far ill advance of what it was years ago, and might be said to cover every requirement (in that department) for producing reliable steel. The study of the metallography of steel has been of great value, also the physical testing of steel, but this knowledge will only de-

Jan 1, 1910

By E. G. Deane

THE CHAIRMAN (P. G. BECKETT, Globe, Ariz.).-The mining of large orebodies has in the last few years been such a big factor in the copper output of this State, and, in fact, of the whole country, I feel that we should have some valuable discussion this evening on the various mining methods described in the papers which are to be read; and I hope you will start a discussion on Mr. Deane's paper. J. A. EDE, La Salle, Ill.-I would like to ask whether, the timbers being left in, they have any fires owing to that fact? E. G. DEANE.-No, we do not. The timbers in the mat seem to lose life. I cannot tell you exactly what change takes place, but they do not burn readily. There is undoubtedly a chemical change in them-a change that makes them lose all strength. I , spoke of the strength of the sills. When we first started, we put in 4 by 8 sills, but those sills had no more strength in 6 months than a 2-in. plank would have. .J. P. HODGSON, Bisbee, Ariz.- I would like to ask Mr. Deane if the central supply raise in the- center of the block has been satisfactory; and also whether in extracting the ore they put small raises up so that wheelbarrows are not used in the stope?

Jan 12, 1916

By Cornelius Kelley

I HAVE been asked to discuss "What Can be Done to Revive the Mining Industry," particularly from the standpoint of the copper industry. It is impossible to consider this problem, if in fact there can be one, from an isolated position. The mining industry is but a part, although a very important one, of that exceedingly complicated machine characterized as commerce, which comprises within its operation and functions the-multitudinous activities that, combined, make up the sum total of the production, manufacture, distribution, sale and utilization of goods and products resulting from the agrarian, industrial and commercial effort of mankind. We survey a world today with its disturbed mass of humanity permeated with discontent, passions loosened by brutal combat not yet brought under control, class hatreds aroused, national prejudices in a state of stimu-lated excitement, governments for the most part enfeebled, some destroyed to their foundations, with fragile structures raised in place of those that seemed enduring, and which have disappeared. A burden of indebtedness incurred in defiance of all economic law exists, to meet the exactions of which, levies of taxation that constitute a grievous burden upon effort and industry are exacted by the needs of those nations that are most favored, while printing presses are busy manufacturing currency that either has, or approaches, a negative value among those less favored. This picture, while not pleasant, is one that should be looked at squarely and carefully appraised in estimating the immediate future. For four years the world marshalled, and exerted without stint, its combined endurance, vitality and resource in an effort of destruction, which violated no less the orderly working of physical and economic laws than it did the conventions of social and civic relations. To have imagined that without travail the orderly processes that governed the relations of mankind could at once be reestablished and begin functioning, was, as has been demonstrated, fallacious; perhaps no more so than the error that is committed today by those opportunists who fail to take cogni-zance of basic conditions which must be remedied be-fore the world can resume its progress to a universally prosperous and satisfactory condition. Please do not gather from this somewhat unpleasant recital that I regard the future with gloomy foreboding or entertain pessimistic doubts, for, emphatically, I do not.

Jan 2, 1922

By Dorsey Hager

The possibility of oil and gas production in Alabama his been little considered as yet. Gas and some oil have been found in northwestern Alabama, near Birmingham, in the Pennsylvanian beds, but the oil and gas possibilities in the Cretaceous beds are not generally appreciated. The recent activity of oil companies in that State has attracted much attention, and in this paper the main structural and the general strati-graphic features are described. Four favorable areas are outlined. These contain folds of major interest. There are other favorable areas which have not been mapped-l Commercial pools discovered in this area would have the advantage of being near tidewater. Mobile, Ala., on the Gulf of Mexico, would be the logical site for refineries and shipping facilities. A pipe line could readily be laid to that city from the Hatchitigbee and the Jackson areas. The logical outlet for the Geneva and the Gordon areas would be Panama City, Ha., on the Gulf of Mexico. Topography The whole of the area under consideration lies in the Gulf coastal plain and slopes gently to the southwest and west. The elevations vary from 200 to 400 ft. (60 to 121 m.) above sea level. The streams have sunk their channels into this gently sloping plain, the main drainage flowing south or southwest into the Gulf of Mexico. Between the

Jan 1, 1918

By J. W. Spretnak, R. Speiser

IT has been suggested that boron in steel may form a film entirely around the austenite grain and that this film is responsible for the boron hardenability effect. In this connection, it is of interest to examine some of the ramifications of the concentration range of boron usually employed in hardenable steels, namely 0.0005 to 0.003 pct in a grain size range of ASTM grain size No. 1 through No. 10. The ratio of the iron to boron atoms and the number of unit cells of y iron per boron atom are listed in Table I. Even at the highest concentration considered, there are 1600 unit cells of y iron per boron atom, assuming a uniform distribution of boron. To investigate the possibility of the boron film formation, the number of boron atoms required to cover the grain surface completely must be calculated. With some transition elements, boron crystallizes in sheets composed of equilateral hexagons very much like graphite.' The selected value for the length of a side is 1.80Å. A simple calculation shows that two boron atoms cover an area of 8.4x l0 -16 sq cm. Table II lists the number of atoms of boron required for the formation of the monatomic film and Table III lists the number of boron atoms per grain. The hypothetical cases of 100 pct and 10 pct adsorption are calculated (all boron atoms in a grain and 10 pct of all boron atoms in a grain are located at the grain surface respectively). In Table 111, all combinations of grain size and composition below and to the left of the solid line (100 pct adsorption) and the dashed line (10 pct adsorption) are excluded as to the possibility of covering the grain surface with a continuous boron film. Thus, even for 100 pct adsorption, the smaller grains can form the film only at the higher concentrations. For the best case, grain size No. 1 and 0.0030 pct B, the required degree of adsorption is 3.9 pct. The above calculations deal only with the number of boron atoms required to form a monatomic film and do not take into account the mechanism of concentration of boron at the grain surface and the possible limitations to the extent of this concentration at a constant temperature, as for example in the austenitizing process. The question next arises as to how this surface concentration can occur during an isothermal treatment. Such surface enrichment of boron must occur through the phenomenon of surface adsorption, i.e., the concentration of solute atoms in solid solution in the vicinity of the surface without precipitation. A solute atom will tend to concentrate at the grain boundary if it reduces the interfacial tension. The possibility of adsorption effects involving both boron and carbon in iron has been discussed.' In general, the tendency for a sol-

Jan 1, 1954

By W. G. Sinclair

The wartime momentum of exploration continued throughout the year 1945 despite the end of hostilities in mid-August. The table below illustrates drilling activity in the various categories: Completed wells. . . . . . . . . . . . . . . . . . . . . . . . 401 Wildcats.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .104 Wildcat discoveries, oil.. . . . . . . . . . . . . . . . . . . 2 Wildcat discoveries, gas-condensate.. . . . . . . 4 Development wells.. . . . . . . . . . . . . . . . . . . . . .297

Jan 1, 1946

By C. C. Wright, R. J. Day

ALTHOUGH data on the exact tonnage of recoverable coal silt are not known, the quantity produced in 1943 was estimated to be over five million tons for the anthracite region of Pennsylvania alone. Since that time the recovery of the No. 5 buck- wheat size previously included in silt estimates has increased greatly thus reducing the total silt tonnage. As a compensating factor, however, the methods of recovering silt previously escaping into the rivers and streams have been markedly improved so that the net figure may not have changed materially. Comparable estimates for bituminous coal are lacking, but undoubtedly the silt represents a significant tonnage. With the trend toward increased wet cleaning of the smaller sizes of bituminous coal, it is to be expected that even greater quantities of silt will be available in the future. The raw silt from anthracite collieries usually contains a high mineral matter content, but technological developments in fine coal cleaning have been making rapid advances and it appears probable that more extensive use of these methods will be employed in the near future. Bituminous coal silt in many instances contains a similar high mineral matter content. As with anthracite silt, however, the cleaning of this material, where necessary, appears both technologically and economically feasible. With a view to upgrading the size and value of silt, considerable laboratory and pilot plant work has been conducted by a number of organizations on what is commonly known as pelletization. Actually the process is one of extrusion in which the moist silt is extruded from a die in the form of rods, which usually break into relatively short lengths-a few inches long-as they fall from the die. Fig I is a photograph of some extruded 3/8-in. diam pellets and of the anthracite silt from which they were produced. This technique of producing larger sized material from fines is by no means new, having been used extensively by the industrial carbon and clay industries for years.' The application of the process to coal silt appears, however, to be relatively new. The first major program of investigation dates back only to July 1945, when a group of engineers representing the Anthracite Institute, The Pennsylvania State College and the J. F. Pritchard and Co. conducted preliminary tests on the extrusion of anthracite silt at the Floridin Co. plant at Warren, Pa. Since that time these three organizations-individually, together, and in co- operation with other interested groups- have actively pursued work on various phases of the problem. Much of the early history and details of the laboratory and pilot plant work by the Anthracite Institute, has been reported by Mulcey and Eckerd.2 It is the purpose of this paper to report additional information on the process, especially with respect to the factors influencing the quality and use properties of the product, and the current develop

Jan 1, 1948

By Hugh Rose

JAY A. CARPENTER, Tonopah, Nev: (communication to the Secretary*).-This description of the Santa Gertrudis mill is of great interest to the operators of similar silver mills in Nevada. At the San Francisco meeting last September there were two excellent papers presented on Nevada silver mills; one by A. H. Jones on The Tonopah Plant of the Belmont Milling Co., and the other by E. E. Carpenter on Cyaniding Practice of the Churchill Milling Co., Wonder, Nev. At the same meeting, I presented a paper on-Slime Agitation and Solution Replacement Methods at the West End Mill, Tonopah, Nev., covering this .particular feature of our milling practice. A comparison of the data presented in these four papers is interesting in that, while the general design and practice is much the same in all cases, there is a wide difference in the design and practice in the various departments of 'the mills. It is to be regretted that Mr. Rose did not round out. this excellent article by following Mr. Jones's and Mr. Carpenter's' lead in giving the average gold and silver content of the ore milled and the resulting tailing, with the consumption of chemicals and the? cost of milling. The practice of the Santa Gertrudis mill in the use of ?cyanide and zinc offers an interesting comparison with that of the Nevada mills, and a discussion of this point may bring out the reasons for the differences that exist.

Jan 12, 1916

AlfreD H. Cowles, Cleveland, Ohio (commuaication to the Secretary*):—Mr.Gillette's paper and his deductions seem to me of the very greatest importance, if the validity of his conclusions and figures can be confirmed. His work seems to solve an unfinished problem that I attempted to solve on the same lines about two years ago, at a time when I was preparing a paper' on another subject for the American Electrochemical Society. The following paragraph is quoted from the paper referred to: "I feel convinced that a further study of the heats of combination now known for so many compounds, which merely express in other terms their voltages of disruption, will show us the allowance that must be made as a departure from unity in the case of each element, for the intrinsic charge of its elementary molecule, and thereby render possible the creation of a table of apparent relative atomic capacities for electricity, similar to the table of atomic weights. With the numerals of this table known, thermal reaction or energy-transformations will be read with the same ease that we now read and trace the shifting of mass

Jan 1, 1904

By C. P. Proctor, J. B. Morrow

With numerous plans under consideration for coal classification, and with the advent of the Bituminous Coal Code, the intelligent sampling of coal has become increasingly important. To us it is rather significant that there have been very few fundamental studies of coal sampling in American technical literature since those of E. G. Bailey, which appeared in the Journal of Industrial and Engineering Chemistry in March, 1909. He covered the subject up to that time so thoroughly and in such an excellent manner that perhaps many other later students have felt that they could add very little to his findings. The recent studies of the British Engineering Standards Association have indicated the possibility of a somewhat different interpretation of Bailey's results, permitting the taking of smaller samples, and perhaps it will now be helpful to reopen this question. C. W. H. Holmes, in an informative series of articles on coal sampling recently published in Colliery Engineering, makes two rather interesting statements, as follows: It is scarcely surprising to find a lack of interest and knowledge regarding the sampling of coal not only in the mining industry itself but also among consumers of industrial fuel: at its best coal sampling is a dirty business, regarded as a nuisance and an expense by the commercial man, and usually as a nuisance and nothing else by the chemist. The writer can conceive only two classes of people who have never experienced any difficulty in obtaining representative samples of coal from wagons; those who have never tried to, and those who have never had the necessity or desire to check the accuracy of their work. The primary purpose of this paper is to present some tabulated data of the more significant results of a sampling investigation undertaken during the last four years to obtain certain fundamental data on the variables connected with coal sampling and to point out that often assumptions have been made that are not in accordance with the facts. One of the standard sampling methods states:

Jan 1, 1936