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By R. A. Vandermeer

It is usually assumed that the rate-determining step in the migration of a grain boundary involves the thermally activated transfer of single atoms across the interface. Chemical reaction rate theory then gives a migration rate which is proportional to the driving force when this is small compared to kT.1 In their recrystallization studies on aluminum, Gordon and vandermeer2 obtained data which was capable of providing the first experimental test of this proportionality. They correlated stored energy (driving force) release measurements determined calorimetrically with fraction recrystal-lized kinetic (growth rate) data acquired metallo-graphically at a temperature where a significant amount of recovery takes place concurrently with recrystallization. Within experimental error, the results of Gordon and Vandermeer confirmed experimentally, at least over a limited range, the linear dependence of boundary migration (growth) rate on driving force in accordance with theory. In obtaining these results, however, an incorrect, implicit assumption was made in relating the average instantaneous growth rate of the recrystallized grains to the measured fraction recrystallized kinetic data. The purpose of this present note is to point out and correct this assumption. An alternate approach, whereby a more proper average growth rate can be calculated from the recrystallization kinetic data, is presented. The earlier data, reevaluated in terms of this new approach, show the same general trend as before so that the original conclusion of Gordon and vandermeer2 is still valid. As was shown in a detailed study3 of the geometrical features of recrystallization in aluminum, the colonies of recrystallized grains can be regarded as uniform cylinders embedded in a three-dimensional matrix, the number of such colonies being constant. Thus during the early stages of recrystallization the volume fraction recrystallized, Xv, can be written as Xv=ynvlr2 [l] where y is a shape factor and i and r are defined as the average length and radius of a recrystallized colony and are spatial averages over the specimen. -nv, is the number of such colonies in a unit of volume. The erroneous assumption made in the earlier paper2 was that r in Eq. [I] could be replaced by

Jan 1, 1965

By J. M. Larkin

GOOD will is becoming recognized more and more as a necessary business asset, and a successful concern must have the good will not only of its customers and the public, but of its employees. Management -enlightened management-recognizes this and will go the limit to get it. Progress depends on cooperation, and in industry cooperation must be based on the acceptance by employ-ers and employees of some practical application of the principle that capital and labor are interdependent. Capital cannot exist without labor, and labor without capital is helpless. The development of each is depen-dent on the cooperation of the other. Confidence and good will are the foundation of every successful enter-prise, and these can be created only by securing a point of contact between employer and employee. We feel that one of the most effective agencies for promoting good will between employers and employees is through some well organized method of conference and have consequently adopted, to accomplish this, a plan of employee representation. The plan inaugurated by the Bethlehem Steel Co. about four years ago, which provides for the election by secret ballot of representatives by and from among the employees, has for its purpose three fundamentals; namely, to give the employees a voice in the determina-tion of the conditions under which they work, to furnish machinery for the prevention and adjustment of differ-ences between employees and management, and, so far as possible, to provide and foster continuous employment. The constitution and by-laws adopted take care of the detail in setting up machinery for the functioning of the representatives of both management and men, but the spirit with which the plan has been carried out and the results which have been accomplished are of far greater importance than the plan itself. The Bethlehem plan, which has been in operation since October, 1918, can no longer be classed as an experiment. The original by-laws provided for amend-ments and, as was anticipated, changes and improve-ments have been made from time to time by mutual agreement. The operation of the plan for over four years shows it to be fundamentally sound and that it must therefore be conceded a success.

Jan 2, 1923

STEPHEN TABER, Columbia, S. C. (communication to the Secretary?). -The fibrous salt crystals described by Dr. Branner are interesting, and I am glad that he has put this additional evidence on record. It confirms the results that I obtained in growing fibrous crystals in the laboratory. Much similar evidence of value to science in interpreting the laws of nature has doubtless been lost through failure to appreciate little things. Mr. Dresser points out that the boundary between chrysotile veins and massive serpentine is finely irregular 'when examined under the microscope. This fact I have observed in studying chrysotile veins and also, mode recently, in studying veins of fibrous calcite and fibrous gypsum. For the latter veins the statement holds true when the walls are of shale as well as when they are of the same material as the veins, but in no instance have I observed any evidence of replacement. The description of the vein walls given in my paper (pp. 1984 to 1985) was megascopic, not microscopic. The fact that chrysotile veins have sharply defined boundaries and are easily separated from the wall rock is evidenced by the small amount of waste adhering to the "crude asbestos" which has been shipped in such large quantities from some of the Canadian mines. Mr. Dresser has good ground for his statement that there seems to be no obvious reason why the term "mass fiber" should be restricted to anthophyllite. I have never examined the serpentine at the East Broughton mines; but in studying other serpentines under the microscope I have noted that much of the so-called "massive serpentine" is really finely fibrous (see pp. 1974 to 1975). The texture of such rock is, however, altogether different from that of mass-fiber anthophyllite, and I believe that the fibers have developed in a different way (see pp. 1981 and .1998). Mr. Graham raises certain objections on the ground that the laboratory production of fibrous crystals was limited to substances which go into solution with decrease in volume. Since my paper was written, however, I have succeeded in obtaining fibrous crystals of ammonium nitrate, a salt that dissolves with expansion in volume.

Jan 5, 1917

By Ralph Arnold

While much geological work and drilling have been done in Venezuela, the incompleteness of geological evidence obtainable and the restricted areas in which drilling has been done make any estimates of oil resources extremely speculative. Nevertheless, it is felt that the data given are justified, in the belief that the ideas of a geologist familiar with the region are better than those of a promoter. The oldest beds of interest to oil men are those of the Cretaceous, which are well developed in eastern Venezuela and about parts of Lake Mara-caibo. In both cases, a hard massive limestone is overlain by a great thickness, most of which is shale. In the west, in places this shale is more than 2000 ft. (610 m.) thick, while in the east it-mag attain 3500 ft. (1067 m.). The limestone and parts of the shale are oil producing. In the east, the Tertiary where present is almost entirely covered by the Quarternary, but in the west it is well developed. In probable unconformity over the Cretaceous shales is found a series of sandstones and shales, which may be called the lower coal series. It is well developed southwest of the lake, where it is the oil container, and is probably the lowest series exposed east of the lake. Above this is the Pauji shale, which is probably the point of origin of all the oil east of Lake Maracaibo and in the State of Falcon. It has a thickness of about 3000 ft. (914 m.) in the Mene Grande region. The upper coal series is developed as a great thickness of sands, shales, and clays, with some partly consolidated limestone. Its thickness may be as great as 10,000 ft. It is the oil container of the Falcon-El Mene region and a probable location for oil in some of the area about the lake. It may or may not include the so-called Maracaibo series in which the oil is found at Mene Grande. Over much of Venezuela, the Quarternary is present in unknown thickness, which probably is not great. It obscures oil structure in all cases and presents the greatest hazard of oil exploration for the fields which probably exist below.

Jan 1, 1923

By J. R. Thoenen

IF ASKED whether limestone production was a mining problem I would; not hesitate to answer emphatically in the affirmative. The question, "When is a quarry a mine?" is familiar. The immediate mental picture induced by the thought of limestone production is that of an open quarry. All are familiar with the open pit in the iron-producing districts of Minnesota and Michigan and the open cuts of the so-called "porphyry" coppers of the West. If these are mines, they differ little from limestone quarries in general mode of operation; if quarries, why do they need the attention of mining engineers? During 1923, the United States produced in round numbers 70,000,000, tons of ore. The limestone production of the United States for the same period was something over 100,000,000 tons. In tons, it about equals the oil production of the United States. The uses of limestone are legion. A paper read by a prominent engineer of Chicago, at the meeting of the National. Crushed Stone Association held last February in St. Louis says: "There is no industry in the United States today that is more basic in its operation or by itself controls. more industries. There is hardly a chemical operation, hardly a metallurgical operation or building operation that a crushed-stone man does not control if he will jump in and make the full utilization of it." Some of the many uses are for road metal, concrete, railway ballast, building stone, riprap, and rubble, the manufacture of iron and steel, alkalies, calcium carbide, magnesia, carbolic and carbonic acids, asphalt filler, mineral wool, poultry grit, sulfuric acid, phosphates, nitrates, soap, baking powder, the purification of copper and prevention of coal-mine explosions, to say nothing of the quantities used in the making of lime and cement. It has been said that without iron we would revert to the Stone Age; how much iron would we have without limestone? From the point. of view of the mining engineer, using the term in its broad sense to include geologists and metallurgists, the production of limestone is important because of its occurrence, volume, commercial importance, and the problems presented by its recovery and treatment.

Jan 2, 1925

By W. H. Fulweiler

The writer would define the term "Use Classification" as a discussion of the qualities that coal should possess to fulfill the requirements of the industry or process in which it is to be used. The general problem of the gas industry is to transform the maximum amount of the thermal energy in coal into a gas of specified quality. The qualifications that a coal should possess to be useful in the gas industry are complicated by probably a greater number of factors than in most industries. The most important of these is the delivered price of the coal. While the- general problem of the industry is as given above, yet the actual problem is the production of gas of a specified quality at the minimum cost. The relative cost of coal and the selling prices for the residuals which are influenced to a large extent by geographical locations are of determining importance as effecting the cost of the gas. It is unfortunate that we cannot disassociate cost figures from a discussion of the desirable characteristics and this results frequently in the use of coal in one location that will be looked upon as quite impossible in another location more favorably situated. Without going into any discussion of the freight rate problem we might merely point out that in general the freight on the coal is equal to or greater than the mine price. It must be evident, therefore, that price must always be considered in any discussion of the effect of the characteristics of a given coal. Two Classes of PRocesses In discussing the characteristics of coals for use in the industry, we must divide the processes in use into two classes: (1) where the coal is destructively distilled at high temperatures resulting in the formation of coke in the liberation of gas and by-products, and (2) where the coal is consumed by combustion in air or steam with a production of gas and by-products leaving only clinker as a residue. The Germans differentiate these two types of processes in their words"' entgasung'" and'" vergasung."' In the distillation processes, we have the effect of the coal on the yield of gas and its quality; the quantity and quality of coke; and the

Jan 1, 1930

By Ralph Arnold

While much geological work and drilling have been done in Venezuela, the incompleteness of geological evidence obtainable and the restricted areas in which drilling has been done make any estimates of oil resources extremely speculative. Nevertheless, it is felt that the data given are justified, in the belief that the ideas of a geologist familiar with the region are better than those of a promoter. The oldest beds of interest to oil men are those of the Cretaceous, which are well developed in eastern Venezuela and about parts of Lake Mara-caibo. In both cases, a hard massive limestone is overlain by a great thickness, most of which is shale. In the west, in places this shale is more than 2000 ft. (610 m.) thick, while in the east it-mag attain 3500 ft. (1067 m.). The limestone and parts of the shale are oil producing. In the east, the Tertiary where present is almost entirely covered by the Quarternary, but in the west it is well developed. In probable unconformity over the Cretaceous shales is found a series of sandstones and shales, which may be called the lower coal series. It is well developed southwest of the lake, where it is the oil container, and is probably the lowest series exposed east of the lake. Above this is the Pauji shale, which is probably the point of origin of all the oil east of Lake Maracaibo and in the State of Falcon. It has a thickness of about 3000 ft. (914 m.) in the Mene Grande region. The upper coal series is developed as a great thickness of sands, shales, and clays, with some partly consolidated limestone. Its thickness may be as great as 10,000 ft. It is the oil container of the Falcon-El Mene region and a probable location for oil in some of the area about the lake. It may or may not include the so-called Maracaibo series in which the oil is found at Mene Grande. Over much of Venezuela, the Quarternary is present in unknown thickness, which probably is not great. It obscures oil structure in all cases and presents the greatest hazard of oil exploration for the fields which probably exist below.

Jan 1, 1923

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 J. M. Morris

THE point to be made most clear in this paper is the economic value of flotation in the Benguet mill flow sheet. It is rather a statement of effect with no attempt at a technical explanation of the cause. Certain well-known, easily understood reagents, mechanisms and principles have been adapted to the conditions at Benguet, and have proved to be more successful than was demonstrated in the laboratory. The mechanical and metallurgical development of this particular operation was arrived at by trial and error, with fortunately very little error. Changes were slow, of necessity, which in the end proved a blessing in that time was afforded for observation and analysis of the disturbing factors; and as a result each change was a definite step towards higher efficiency. Many of these steps were unpredictable from labora-tory work because of the varied and differing characteristics of ores met with in daily operation of the mill, which were practically impossible to reproduce on a laboratory scale. The Benguet mill receives daily ores that differ as much as if they were delivered from three different properties. There is first the surface and upper-level zone, which produces an oxidized secondary ore contain-ing considerable iron oxide, manganese oxide and some organic matter. Formerly, most of this ore consisted of very soft fill with some hard rock mixed in. It also contained an unusual amount of iron and aluminum sulfate, which formed hydrates upon entering the alkaline cyanide solu-tion and caused excessive frothing. When flotation was introduced in the Benguet mill the general char-acteristics of this upper-level ore had changed considerably, in that it was practically all newly mined, fairly hard ore. It still contained many of the same disturbing elements, but was somewhat simpler to treat than formerly. The small proportion of fines is still troublesome in flotation, and plant practice probably does not show more than 80 per cent extraction on this small portion of the ore. No definite figure on this is available, as this particular ore is delivered at irregular intervals

Jan 1, 1936

By A. F. Brock

The cut-and-fill mining methods in use in the mines of The International Nickel Company of Canada Limited, at Falconbridge Nickel Mines Limited, in the Sudbury District, and at McIntyre Porcupine Mines Limited in the Porcupine District, are typical of the general cut-and-fill practice in both the base-metal mines and the gold mines in the Province of Ontario. The following pages describe the methods in use. HORIZONTAL CUT-AND-FILL STOPING Horizontal cut-and-fill stoping, as practiced in the mines of The International Nickel Company of Canada Limited, falls into two main classifications: (I) transverse cut-and-fill stoping, where ground conditions or wide ore bodies make it necessary to establish narrow stopes and pillars across the width of the ore body; (2) longitudinal cut-and-fill stoping where ore body widths and ground conditions allow safe mining of the full width of the ore body. Transverse Cut-and-fill StopiNg General Stoping Layouts Stope and Pillar Widths.—For transverse stoping, experience has indicated that narrow stopes and pillars, 27 ft. 6 in and 22 ft., respectively, are most satisfactory. These width are multiples of 5 ft. 6 in., which is the center to center dimension of a standard square set. Thus any stope, or block of stopes, can be readily converted from cut-and-fill to square set-and-fill if ground conditions should warrant such a change. Formerly, pillars were established 16 ft. 6 in. wide, the equivalent of the width of three square sets, with the intention of extracting the pillars by mining an overhand slice one set wide and an underhand slice two sets wide. However, subsequent experience proved that a two-set overhand slice is so much more efficiently mined than a one-set slice, and 22-ft. pillars have been made standard. Chutes.—The stope chutes are established on the longitudinal center line of the stopes and are spaced at 22-ft. centers from footwall to hanging wall. The footwall chute is usually from 5 to 10 it. from the footwall of the stope. It is offset where necessary at an angle of 52° and vertical chutes are carried from the offset at 22-ft. centers. In sections of the ore body where a flat hanging wall would cut off hanging-wall chutes within a few cuts of the sill, it has proved to be more economical to use temporary chutes or slushers, or both, for these first few cuts, rather than to el permanent chutes at the hanging wall.

Jan 1, 1946

By Oscar T. Marzke

Four alloys that precipitate the alpha phase from the beta of the copper-zinc system were heat-treated in various ways to develop as many forms of the segregate as possible. It was found that the precipitate may have the form either of plates or of needles. Plates usually result when precipitation occurs at low temperatures and needles when precipitation takes place at high temperatures. The needles tend to align themselves along certain planes in the matrix and to coalesce into plnte-like structures. The two phases were found to be related so that a (111) plane and [Oil] direction of the precipitate are parallel to a 10111 plane and 11111 direction of the matrix. DISCUSSION (E. A. Anderson presiding) D. W. Smith, Pittsburgh, Pa. (Written discussion).—Tllis report by Dr. Marzke covers completely all possible heat treatinents over a considerable range of compositiol~s in which a1pha precipitates from beta brass, and may be said to complete the Inctallographic part of this problern The lining up of ncedles of segregate to form plates, espeeially as shown in Fig. 5, appears to he regular, although the author's frequency plot in Fig. 11 makes it appear rather irregular. Has the author attempted anY correlation between some of the major dircetions and the oricntntaion of the parent grain as determined by X-ray analysis? Also, in Figs. 4, 5 and 6 the cross-sections of the needles appear to be straightsided and regular. Have these directions been correlated with the matrix latttice? Dr. Mnrzkr 's method of interpretation of the orientation rclationships between the alpha. and beta phases is a bit uncertain and seems to wed more explanation. If this relationship, as staited is such that :L (1111 plane and a [I 10] direction of that plane in the precipitate is parallel to a. {110} p1ane and a [111] direction of that, plane in the matrix, there mill be a maximum of 24 possible orientations of the alpha phase within a. single grain of the beta phasc. This relationship is expressed strercographical1y in Fig. 13, ill which the locations of a11 of the alpha {111} poles for the 24 orientations of alpha me given. Fig. 12 chccks fairly closely with this thcoretical plot,. with a few exeeptions which may be due to the inaceuracy inherent in the method used by the anthor in determining the orientations of the segregates. The method might have been refined somewhat had corrections been made for the displacement of the slip p1ancs upon deformation.

Jan 1, 1933

By S. Yukawa, M. J. Sinnott

A high resolution autoradiographic study of the diffusion of a nickel isotope (NP3) into copper in the temperature range of 650° to 925°C, with particular emphasis on grain boundary diffusion, has been made. The extent of grain boundary diffusion is a function of the grain boundary angle and the diffusion temperature. The ratios of the grain boundary diffusion coefficient to the lattice diffusion coefficient ranges from 104 to 105. The activation energy for grain boundary diffusion decreases with increasing grain boundary angle. STUDIES and reviews&apos;-8 of metallic diffusion have indicated that grain boundary diffusion is a common phenomenon but quantitative studies of the many variables involved are not numerous. The present work was concerned with determining the influence of the crystallographic orientation of the grain boundaries and the temperature on the extent of boundary diffusion of nickel into copper. The study involved essentially three steps: 1—the production of grain boundaries of known crystallographic orientation, 2—the determination of the extent of diffusion into the boundaries, and 3—the analysis of the resulting data in terms of the usual diffusion concepts. The grain boundaries investigated approximated the simple tilt variety having l° of freedom. They were produced by controlling the solidification from a melt of Cuprovac (a high purity vacuum-melted copper obtained from Vacuum Metals Corp.) of a pair of seed crystals so that the bicrystals of copper produced had a common <100> axis. By rotating one seed crystal relative to the other, a simple tilt boundary was produced. The angle of rotation between the two crystals is the grain boundary angle 8, or what is sometimes termed the misfit angle. In all, some 16 boundaries ranging from 2" to 72" in 5" to 10" steps were investigated. The crystallographic orientations were measured with the use of both X-ray and optical goniometric techniques. The <100> axes in the crystals were found to be parallel within 2" to 3" with the exception of one crystal (8 = 12") in which the axes were 6" from being parallel. All bicrystals showed evidences of sub-grain structures. Laue analyses showed that these subgrains differed in orientation up to a maximum of 2". Because of these variations, and some curvature in the boundaries, the grain boundary angles listed are actually average values and deviate from the 1 o of freedom boundaries. The stripping film technique of high resolution autoradiography was used to detect the diffusion of the nickel isotope into the grain boundaries of the bicrystals of copper. Kodak experimental permeable stripping film with an emulsion layer 5 u thick

Jan 1, 1956

By Howard I. Smith

THE mineral trona was discovered on Government land in 1938, about 18 miles west of the town of Green River, Wyo., in the core of the John Hay, Jr., well, a test well drilled for oil by the Mountain Fuel Supply Co. in sec. 2, T. 18 N., R. 110 W., sixth principal meridian. Although no oil or gas was reported, the drilling led to a discovery of great potential economic importance and exceptional scientific interest. Trona is a relatively rare mineral found at various places in playa deposits but not previously found at any great depth. It is composed of hydrous sodium carbonate and sodium bicarbonate (Na2CO3.NaHCO3.2H20). Pure trona contains the equivalent of 70.35 per cent of sodium carbonate. Total sodium computed to carbonate times 1.42 equals the percentage of trona in the absence of other sodium carbonate minerals in the sample. ANALYSES Two short pieces of core sent to the author a few days after the completion of the Hay well were analyzed by R. C. Wells[t] and found to be exceptionally pure trona. A brief article on this discovery has already been published.1 Arrangements were then made through W. T. Nightengale[$] for the author to inspect and sample the core. The company log of the well included notations of sodium salt crystals from a depth of 1190 to 1820 ft. Not being able to identify all the minerals present, the author selected several specimens of the core for petrographic examinations and sampled the sections of trona for analysis. J. J. Fahey, of the Geological Survey, examined the specimens and reported most of the crystals to be a new anhydrous sodium carbonate and calcium carbonate mineral (Na2CO3.2CaCO3), which he named shortite,2 after Maxwell N. Short.* He analyzed the samples of trona, with the results shown in Table I. [ ] In addition to the 10 ft. I in. of trona in the first section, it is reasonable to assume that the 9 ft. 8 in. for which no core was available for sampling is either mostly trona or some other soluble salt, but it should not be included in calculating reserves. In the part of the core between 1590 ft. 3 in. and I600 ft. 4 in. the material insoluble in cold water, amounting to about 5 per cent, was estimated petrographically to contain 70 per cent clay, 25 per cent shortite, and 5 per cent pyrite. ACCOMPANYING MINERALS Fahey later secured about 600 ft. of the core for a detailed examination and study

Jan 1, 1942

By Joseph L. Jernegan

The Whale Lode occurs in the main range of the Rocky Mountains, Park County, Colorado Territory, at Hall Valley. It has been opened up and worked to some extent by the Whale Mine, situated some 11,300 feet above the level of the sea. The mine, with 700 feet of the lode on either side of the discovery shaft, is the property of the Hall Valley Silver-Lead Mining and Smelting Company. The adjacent country rock is a compact, fine-grained gneiss; its general strike is about north and south, dipping steeply to the west. In the immediate vicinity of the mine, the strata are very nearly vertical. The gneiss incloses numberless veins of a reddish granite, in which the feldspar largely predominates over the quartz and mica, the latter oftentimes being scarcely perceptible. As a general rule these granitic veins seem to more frequently follow the lines of stratification of the gneiss than otherwise. They are of varying width, some large, some small; the larger are from 5 to 6 feet wide. Gash veins of feldspar and quartz are also of very frequent occurrence. The general trend of the lode is about northeast. and southwest, intersecting the country rock at about an angle of 45 to its stratification. It dips to the northwest at an angle of 65. I am unable to state accurately how far this lode has been traced upon the surface, but it is at least well known to extend entirely through the mountain upon which the mine is situated, and is traceable over the ridge by a hollow extending for some distance along the surface, in which the lode crops out. This hollow in the surface rock has probably been formed through decomposition of the vein matter by atmospherical influences. The width of the crevice is variable, generally between 5 and 10 feet; the pay vein varies from an inch, or less, to 36 inches. The vein is generally accompanied both on foot and hanging walls by a whitish, semi-decomposed fock, composed of quartz and decomposed feldspar, and in some places—where the process of decomposition has not reached as advanced a stage—a lightgreenish or black mica. This rock, therefore, is in places composed of all the constituents of gneiss, and is undoubtedly nothing more or less than the same in a decomposed condition. It is often very strongly impregnated with iron pyrites, generally crystallized in minute cubes, and it is probably owing to the presence of this min-

By S. A. Wookey

More than 90 per cent of the ore produced by stoping at McIntyre is mined by horizontal cut-and-fill methods. The remainder is mined by square set and fill. In the stopes on the upper levels, mill holes are spaced 80 ft. apart and usually it is feasible to mine the breast for the full distance between the mill holes in one operation and to break, clean out and fill without any support for the roof or walls, other than the odd crown bar or sprag. The ore is scraped to the mill holes by small (10 to 15 hp.) air-operated slusher hoists. No grizzlies are used over the chutes and care is taken to break up the big pieces beforehand. Fill usually is spread by tramming sand or waste in a one-ton car from the fill raise. Fill raises are driven parallel to the strike of the vein and are inclined at approximately 48°. In long stopes, where more than one fill raise is necessary, they are spaced about 300 ft. apart. It is sometimes necessary to stand square sets for a short distance each way under the brow of the fill raise. support needed increases and on the lower levels and in some wide stopes where closer support of the back is necessary, it has become standard practice to timber the stope with 12 by 12-in. timber. Rough timber sets consisting. of caps, tightly blocked to the back and supported on posts 7 ft. high, are placed at about 5 ft. intervals. These sets are generally salvaged from the lower breast before blasting and are used again on the upper slice after the fill has been placed. In general, two or three breasts may be broken down before mucking out and filling and the ground stands long enough to enable this to be done safely. On the lower levels and in certain wide stopes and in heavy ground, a more intermittent method must be used. Only one breast or even part of a breast can be blasted and the back must be timbered before the ore can be removed. In these cases, sill timbers 16 ft. long, supported at one end on posts from the fill and at the other end on pins inserted in holes drilled in the face, are used. Timber cribs 5 by 9 ft. built from the fill to the roof and tightly blocked to the back are used throughout the mine to reinforce both the timber sets and the square sets.

Jan 1, 1946

By Fred E. Beasley

Metallurgists have, in the last ten years, overcome many difficulties of high zinc in lead blast-furnace slags. This problem was brought to the front at the close of the war, by the price obtained for lead and the high cost of labor, fuel, and flux. The Port Pirie plant of the Broken Hill Associated Smelters, Australia, early in 1919 had increased the zinc oxide in its blast-furnace slags from 13.5 to 20 per cent., at the same time reducing the iron oxide in the slag from 33.5 to 25.6 per cent. These results were obtained by the addition of 10 to 12 per cent. granulated slag to the roaster charge, improved conditions of the crushing, mixing, and roasting of the constituents of the sinter. By experiments and improvements, the practice at this plant has developed a normal slag that carries 22 per cent. zinc oxide, and at times runs as high as 33 per cent. zinc oxide, with only slight furnace trouble. The granulated slag is used not only as a diluent to the sulfur in the roaster charge, but on account of its value as a slag-forming material and the physical properties it imparts to the finished sinter. The ore is mixed with flux and given a double roast. All the first roasting is by sintering with the Dwight & Lloyd machines. The final roasting is performed partly by Dwight & Lloyd machines and partly by H. & H. pots. The charge to the blast furnace consists chiefly of the final sinter, slag shells, siliceous and non-bearing sulfur lead ores. High blast and ore columns are the practice. The greatest care is taken to obtain in the final sinter as low a sulfur content as possible. Attracted by the success of the Port Pirie plant, The Consolidated Mining & Smelting Co. of Canada, at Trail, B. C., in 1920 treated its crushed primary sinter with about 15 per cent. granulated slag. The Trail smelter at this time was short of ore and a large part of the charge to the roasters consisted of the zinc-plant residue having the following analysis: 12 to 16 per cent. lead, 12 to 16 per cent. zinc, and 25 to 30 per cent. iron. The lead in the final sinter was low and the physical condition was so bad that all the sinter had to be screened before it could be charged to the blast furnace. Also it disintegrated on being trammed and dumped

Jan 1, 1925

Discussion of the paper of Dorsey A. Lyon and Robert M. Keeney, presented at the Butte meeting, August, 1913, and printed in Bulletin No. 80, August, 1913, pp. 2117 to 2149. C. D. WOODWARD, Butte, Mont.:-We constructed a small blast furnace, and used first carbon electrodes and an alternating current of about 50 to 75 volts. We were able to smelt the material which was fed to the furnace, but we did not carry on experiments far enough to see just exactly what the power consumption was and compare it with the amount of material treated. We found that the blast seemed to help materially in reducing our charge and cutting down our power consumption. There were several other experiments tried at the time, and I do not call to mind now just what they were. We were trying to do away with the carbon electrode and replace it with an iron one, and it also seems to me we tried to use the ore for an electrode; but I believe that the electric furnace in the reducing end is simply a question of British thermal units per kilowatt-hour compared with British thermal units in a pound of coke. Now, if a pound of coke costs us 0.5 c. and a kilowatt-hour costs us in the neighborhood of 1.5 c., I think there is a big advantage in using coke instead of the electrical current for copper reducing. We tried steam, and a number of other methods, to throw copper down, but it has been some time ago and I am not very familiar with them now. The outlook of the experiments did not seem to be very promising, and we took it more as a thermal problem than an electrical one. PROF. JOSEPH W. RICHARDS, South Bethlehem, Pa.:-Mr. Woodward has spoken of the question as a thermal problem. I would call attention to the fact that electric furnaces usually utilize the heat of the electric current at from four to ten times the efficiency with which the heat generated by fuel is utilized; so it will not do simply to compare by thermal units generated. Your total thermal units may cost much less from coke than from electricity, yet you will find the electrically generated thermal units utilized in a properly designed furnace from three to ten times more efficiently than in the combustion furnace. You must make that allowance is comparing the cost of thermal units generated electrically and thermal units from coke.

Jan 11, 1913

The cut-and-fill mining methods in use in the mines of The International Nickel Company of Canada Limited, at Falconbridge Nickel Mines Limited, in the Sudbury District, and at McIntyre Porcupine Mines Limited in the Porcupine District, are typical of the general cut-and-fill practice in both the base-metal mines and the gold mines in the Province of Ontario. The following pages describe the methods in use. HORIZONTAL CUT-AND-FILL STOPING Horizontal cut-and-fill stoping, as practiced in the mines of The International Nickel Company of Canada Limited, falls into two main classifications: (I) transverse cut-and-fill stoping, where ground conditions or wide ore bodies make it necessary to establish narrow stopes and pillars across the width of the ore body; (2) longitudinal cut-and-fill stoping where ore body widths and ground conditions allow safe mining of the full width of the ore body. Transverse Cut-and-fill StopiNg General Stoping Layouts Stope and Pillar Widhs.—For transverse stoping, experience has indicated that narrow stopes and pillars, 27 ft. 6 in and 22 ft., respectively, are most satisfactory. These width are multiples of 5 ft. 6 in., which is the center to center dimension of a standard square set. Thus any stope, or block of stopes, can be readily converted from cut-and-fill to square set-and-fill if ground conditions should warrant such a change. Formerly, pillars were established 16 ft. 6 in. wide, the equivalent of the width of three square sets, with the intention of extracting the pillars by mining an overhand slice one set wide and an underhand slice two sets wide. However, subsequent experience proved that a two-set overhand slice is so much more efficiently mined than a one-set slice, and 22-ft. pillars have been made standard. Chutes.—The stope chutes are established on the longitudinal center line of the stopes and are spaced at 22-ft. centers from footwall to hanging wall. The footwall chute is usually from 5 to 10 ft. from the footwall of the stope. It is offset where necessary at an angle of 52° and vertical chutes are carried from the offset at 22-ft. centers. In sections of the ore body where a flat hanging wall would cut off hanging-wall chutes within a few cuts of the sill, it has proved to be more economical to use temporary chutes or slushers, or both, for these first few cuts, rather than to el permanent chutes at the hanging wall.

Jan 1, 1946

By Howard I. Smith

THE mineral trona was discovered on Government land in 1938, about 18 miles west of the town of Green River, Wyo., in the core of the John Hay, Jr., well, a test well drilled for oil by the Mountain Fuel Supply Co. in sec. 2, T. 18 N., R. 11o W., sixth principal meridian. Although no oil or gas was reported, the drilling led to a discovery of great potential economic importance and exceptional scientific interest. Trona is a relatively rare mineral found at various places in playa deposits but not previously found at any great depth. It is composed of hydrous sodium carbonate and sodium bicarbonate (Na2CO3.NaHCO3.2H2O). Pure trona contains the equivalent of 70.35 per cent of sodium carbonate. Total sodium computed to carbonate times 1.42 equals the percentage of trona in the absence of other sodium carbonate minerals in the sample. ANALYSES Two short pieces of core sent to the author a few days after the completion of the Hay well were analyzed by R. C. Wells† and found to be exceptionally pure trona. A brief article on this discovery has already been published.1 Arrangements were then made through W. T. Nightengale‡ for the author to inspect and sample the core. The company log of the well included notations of sodium salt crystals from a depth of 1190 to 1820 ft. Not being able to identify all the minerals present, the author selected several specimens of the core for petrographic examinations and sampled the sections of trona for analysis. J. J. Fahey, of the Geological Survey, examined the specimens and reported most of the crystals to be a new anhydrous sodium carbonate and calcium carbonate mineral (Na2CO3.2CaCO3), which he named shortite,2 after Maxwell N. Short.* He analyzed the samples of trona, with the results shown in Table i. [ ] In addition to the 10 ft. I in. of trona in the first section, it is reasonable to assume that the 9 ft. 8 in. for which no core was available for sampling is either mostly trona or some other soluble salt, but it should not be included in calculating reserves. In the part of the core between 1590 ft. 3 in. and 1600 ft. 4 in. the material insoluble in cold water, amounting to about 5 per cent, was estimated petrographically to contain 70 per cent clay, 25 per cent shortite, and 5 per cent pyrite. ACCOMPANYING MINERALS Fahey later secured about 600 ft. of the core for a detailed examination and study

Jan 1, 1942

By Charles W. Carter, Alfred H. Bell

In 1942, Illinois produced 106,590,000 bbl. of crude oil, or 7.6 per cent of the entire amount produced in the United States. It ranked fifth among the oil- producing states. The production for 1942 declined 20.5 per cent from the previous year&apos;s total of 134,139,000 bbl. Tie daily average production for 1942 was approximately 292,000 bbl., or 74,000 bbl; less than the 366,000 daily average for 1941. At the beginning of 1942 the daily production was 367,000 bbl. This production declined steadily to 282,000 for June and to 246,000 for December. This steady decline was caused partly by the reduction in drilling resulting from Federal Conservation Order M-68 and partly by the fact that no major pool was found during the year. Discoveries Forty new fields (Fig. 2, Table 2), 48 extensions (Table 3), and 45 additional producing zones in existing fields (Table 4) Were discovered in 23 counties in Illinois during 1942. Of the 40 new fields, three

Jan 1, 1943