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By Fred W. Gordon

The North Chicago Rolling-Mill Co., of Chicago, have four furnaces at South Chicago, built during 1881. Each furnace is 20 feet diameter of bosh, and 75 feet total height, the hearth being 11 feet diameter, and the top 15 feet 4 inches. They are blown through seven 7-inch tuyeres placed 5 feet 6 inches above the hearth level. Cubical contents, 15,000 cubic feet. Each furnace is supplied with 2 blowing engines, 84-inch blowing cylinder, and 36-inch steam cylinder, and 54-inch stroke. These two have one jet-condenser worked by an auxiliary pump. The blast for each furnace is heated by the aid of three Whitwell fire-brick stoves, each 21 feet diameter and 60 feet high. In the batteries of boilers furnishing steam for four furnaces there are 36 double-length boilers, 76 feet long, 48 inches diameter and 16,000 square feet heating-surface. The plant was designed to produce 3600 tons per week, or 900 tons for each furnace, and was fitted as above with such engines, boilers, and hot-blast stoves as were thought requisite for that production ; hence, calculated from the present make—not the least remarkable feature is the economy of construction—there are less engines, less boilers, and less hot-blast power for the iron made than at ally plant within my knowledge, or it could to-day be duplicated for less money per ton of iron made per week than could any plant now in existence, whether using fire-brick or cast-iron stoves for heating the blast. This is a practical demonstration of my assertion in a paper on fire-brick stoves, read before the Institute," that the application of fire-brick stoves in construction really lessens the first cost. In view of the statements just made, I must be most emphatic in assuring the members that nothing is strained or overburdened.

Jan 1, 1886

By E. S. Bardwell

Each of the three refining furnaces in use at Great Falls is provided with a waste-heat boiler. The general arrangement of furnace and boiler is as shown in Fig. 1. Two of the furnaces have hearths 45 ft. 7 in. by 14 ft. 6 in.; the third has a hearth 46 ft. 101/2 in. long and of the same width as the other two. The furnaces at present are equipped for firing with natural gas. As originally constructed two of the furnaces had hearths 36 by 14 ft., and were designed to use coal on grates, but these furnaces were lengthened and fired successively with pulverized coal and oil. The third furnace was added in 1926 and was oil-fired until 1928. Since that year natural gas has been in use on all of the furnaces. The changes that have occurred in connection with furnace design and the comparative performance of the furnaces with various fuels were described1 by the author in 1932. Two of the furnaces are provided with Stirling class A-30 boiler. rated at 400 hp. and having 4008 sq. ft. of heating surface. The thir furnace has a class A-21 Stirling waste-heat boiler rated at 300 hp. with 2805 sq. ft. of heating surface. The boilers are not baffled. The waste-heat boilers are placed on a platform 17 ft. 3 in. above the level of the furnace charge floor. The waste gases from the furnace pass by a vertical uptake flue, 4 by 3 ft. inside at the point where it enters the chamber, to a brick chamber from which the gases pass over a bridge wall and into the boiler setting. The uptake flue and chamber are constructed of silica brick. Each furnace has a steel stack 125 ft. high, measured from the boiler floor. The stacks have a 41/2-in. firebrick lining and are 5 ft. in diameter

Jan 1, 1934

By John Henry Harden

IT appears that in the earlier days of anthracite coal mining, 1824-25, the Lehigh region mined 76 per cent. of all the coal sent to market. During the same period Wyoming sent 12 and 5 per cent. respectively, whilst the Schuylkill sent 11 and 18 per cent., the number of tons marketed being in those days very small indeed. In the year 1828 the Schuylkill region mined over one-half of all the coal sent to market, and continued to do so for thirty years (with the exception of the year 1831), until 1858 ; since that date the pro¬duction has declined very steadily in comparison with the other regions, until, in 1876, it was only 34 per cent. Wyoming, in the year 1820, was mining 40 per cent., but the production of all the regions was very small ; in six years it declined to 5 per cent., increased to 34 per cent. in 1831, declined to 10 per cent. in 1838. Since which time the increase has been gradual, until 1873-75 Wyoming produced over 50 per cent. of all the anthracite coal sent to market. In 1867 the production exceeded that of Schuylkill, and has continued to do so since that time. In the year 1876, during the existence of the " coal combination," Wyoming lost 9 per cent. ; during the same time Lehigh gained 7 and Schuylkill 2 per cent. over their relative production of the preceding year, the decrease of Wyoming being two and a half million tons, the increase of the Lehigh one million, the decrease of the Schuylkill nearly three-quarters of a million. The extraordinary production of the Lehigh region at a time of decreased demand and in opposition to an agreement with the other regions to limit the supply to the supposed demand was the cause of the disagreement which ultimately broke up the combination of the great coal-producing and carrying companies. The Lehigh region produced very steadily, from 1829 to 1854, an average of about 22 per cent. of the whole production. From 1854

Jan 1, 1877

By Kenneth Cottingham

The year 1941 brought a considerable increase in drilling activity in Ohio. In 1940, the total of wells completed was 1228, whereas in 1941 it was 1561, or an increase of approximately 27 per cent. Of the 1561 wells, 333 were oil wells, 701 gas wells and 527 dry holes. The completions for the past five years are shown in Table I; the number of productive oil or gas wells for the year 1941, arranged by producing formations, are given in Table 2; the number of wells, oil, gas or dry, completed in each county in 1941, in Table 3, and wells by sands in Table 4. The production of oil increased by about 500,000 bbl. in 1941, nearly all of the increase being in Pennsylvania grade. In 1940, the total production was 3,052,000 bbl. from 25,500 wells. In 1941 the total production was 3,547,534 bbl. from 24,801 wells. The increase in production is chiefly due to the Clinton pool in Clayton township, Perry County, which is briefly men- tioned later in this review. The number of oil wells, by grades of oil, and the total quantities produced are shown in Table ;. Annual oil production for five years is listed in Table 6. The average prices paid for crude in 1941 were slightly higher than in 1940 These 1941 prices, with dates of change, are shown in Table 7. The maximum production of natural gas in Ohio was in the year 1915, when the total was just under 80 billion cu. ft. The maximum consumption occurred in the year 1916, and was approximately 169 billion cu. ft. For the past several years, Ohio has ranged from eighth to eleventh, in order of gas production for the different states, being in tenth place in 1940. In the matter of consumption, however, Ohio remains in fifth place. Preliminary figures for 1940 indicate that production of natural gas increased II per

Jan 1, 1942

By Kenneth Cottingham

The year 1941 brought a considerable increase in drilling activity in Ohio. In 1940, the total of wells completed was 1228, whereas in 1941 it was 1561, or an increase of approximately 27 per cent. Of the 1561 wells, 333 were oil wells, 701 gas wells and 527 dry holes. The completions for the past five years are shown in Table I; the number of productive oil or gas wells for the year 1941, arranged by producing formations, are given in Table 2; the number of wells, oil, gas or dry, completed in each county in 1941, in Table 3, and wells by sands in Table 4. The production of oil increased by about 500,000 bbl. in 1941, nearly all of the increase being in Pennsylvania grade. In 1940, the total production was 3,052,000 bbl. from 25,500 wells. In 1941 the total production was 3,547,534 bbl. from 24,801 wells. The increase in production is chiefly due to the Clinton pool in Clayton township, Perry County, which is briefly men- tioned later in this review. The number of oil wells, by grades of oil, and the total quantities produced are shown in Table ;. Annual oil production for five years is listed in Table 6. The average prices paid for crude in 1941 were slightly higher than in 1940 These 1941 prices, with dates of change, are shown in Table 7. The maximum production of natural gas in Ohio was in the year 1915, when the total was just under 80 billion cu. ft. The maximum consumption occurred in the year 1916, and was approximately 169 billion cu. ft. For the past several years, Ohio has ranged from eighth to eleventh, in order of gas production for the different states, being in tenth place in 1940. In the matter of consumption, however, Ohio remains in fifth place. Preliminary figures for 1940 indicate that production of natural gas increased II per

Jan 1, 1942

By A. M. Nicholas

WHEN attempting to lift mill pulp containing a considerable percentage of wolframite, in an ordinary bucket elevator, difficulty was encountered from the tendency of the tungsten minerals to settle, on account of their high specific gravity. Lifts not exceeding 20 ft. (6m.) could be accomplished without particular difficulty, because there was insufficient time for consolidation of the heavy minerals in the bottom of the bucket; but with higher lifts, the heavy tungsten minerals would settle so solidly that when the bucket turned over at the top of the elevator the contents could be only partially dumped. In this case it ,was necessary to lift the material a distance of 34 ft. (10m.); hence some means had to be adopted to prevent settling, at least to such an extent that the material could be dumped from the buckets. To reduce the carrying time to a sufficient extent would have required a belt speed of 475 ft. (144.7m.) per minute, which was not feasible. It was decided to try, by vibrating the belt about midway of its span, to keel) the material sufficiently agitated during elevation to prevent settling. Underneath the rising side of the belt was placed a 12-in. (30.48-cm.) idler pulley, 18 ft.-(5.5 in.) up in the total lift of 34 ft. The idler pulley was set eccentric by 3/4 in. (19 mm.) and it was hoped that the vibration thus imparted to the belt, running at a speed of 280 ft. (85 m.) per minute, would prevent settling in the buckets. It was found that the pressure of the belt on the idler, due to the small inclination of the elevator, was not sufficient to overcome sliding on the idler, and the agitation was insufficient to accomplish the desired purpose. The idler was then connected to the drive shaft of the elevator through an intermediate pulley, gearing down to a speed of 20 r.p.m., so that a positive vibration was imparted to the belt; this imparted enough motion to the belt to prevent settling and the contents of buckets clumped satisfactorily.

Jan 2, 1918

By R. K. Waring, E. C. Truesdale

The Research Division of The New Jersey Zinc Company (of Pa.) has conducted, over a period of years, numerous tests of the reducibility of various zinc ores and the reactivity of various kinds of coal, using a number of different experimental methods. Most of these tests have involved the reduction of mixtures of ore and coal. In such cases the following simultaneous reactions are believed to be mainly responsible for the production of zinc, as was shown by Bodenstein1 some years ago: ZnO+ CO = Zn + CO2 [1] C + CO2 = 2 CO [2] Each of these reactions is dependent upon the other for the supply of CO and CO2 , respectively, and the over-all rate of formation of zinc vapor will be determined by the slower of these two reactions. An analogous pair of reactions sometimes of importance is: ZnO + H2 = Zn + H2 O [31 C + H2O = CO + Ha [4] While it is possible to obtain an indication of the relative reducibility of various ores, or of a fine versus a coarse ore, by testing them with a given coal, and while coal reactivities may be measured in a corresponding manner, a more direct determination of relative reaction rates is possible by carrying out the desired reactions, such as I and 2, separately and under reproducible conditions. It is one purpose of this paper to present some of the results that have been obtained by the latter method. C. G. Maier2 discusses the relative rates of reactions I and 2 and concludes that while at relatively low temperatures reaction I is faster than reaction 2, this difference becomes less with increasing temperatures, although at smelting temperatures reaction I is still the faster. He also says (p. 48), "At temperatures . . . between IIOO° and I3oo°C., . . . the zinc oxide reduction reaction is intrinsically more rapid than its physical limitations; that is, it is limited by gas diffusion rates." In the course of numerous reactivity tests involving the separate use of reactions and I and 2, we have obtained data that show by direct experiment, we believe for the first time, the correctness of Maier's statements concerning these reactions. We also include data on the relative rate of reaction 3, involving reduction by hydrogen. Finally, some interesting results obtained by carrying out the reduction of a zinc ore-coal briquet in streaming atmospheres of nitrogen, carbon monoxide and hydrogen, respectively, are presented. *

Jan 1, 1943

By E. C. Truesdale, R. K. Waring

The Research Division of The New Jersey Zinc Company (of Pa.) has conducted, over a period of years, numerous tests of the reducibility of various zinc ores and the reactivity of various kinds of coal, using a number of different experimental methods. Most of these tests have involved the reduction of mixtures of ore and coal. In such cases the following simultaneous reactions are believed to be mainly responsible for the production of zinc, as was shown by Bodenstein1 some years ago: ZnO+ CO = Zn + CO2 [1] C + CO2 = 2 CO [2] Each of these reactions is dependent upon the other for the supply of CO and CO2 , respectively, and the over-all rate of formation of zinc vapor will be determined by the slower of these two reactions. An analogous pair of reactions sometimes of importance is: ZnO + H2 = Zn + H2 O [31 C + H2O = CO + Ha [4] While it is possible to obtain an indication of the relative reducibility of various ores, or of a fine versus a coarse ore, by testing them with a given coal, and while coal reactivities may be measured in a corresponding manner, a more direct determination of relative reaction rates is possible by carrying out the desired reactions, such as I and 2, separately and under reproducible conditions. It is one purpose of this paper to present some of the results that have been obtained by the latter method. C. G. Maier2 discusses the relative rates of reactions I and 2 and concludes that while at relatively low temperatures reaction I is faster than reaction 2, this difference becomes less with increasing temperatures, although at smelting temperatures reaction I is still the faster. He also says (p. 48), "At temperatures . . . between IIOO° and I3oo°C., . . . the zinc oxide reduction reaction is intrinsically more rapid than its physical limitations; that is, it is limited by gas diffusion rates." In the course of numerous reactivity tests involving the separate use of reactions and I and 2, we have obtained data that show by direct experiment, we believe for the first time, the correctness of Maier's statements concerning these reactions. We also include data on the relative rate of reaction 3, involving reduction by hydrogen. Finally, some interesting results obtained by carrying out the reduction of a zinc ore-coal briquet in streaming atmospheres of nitrogen, carbon monoxide and hydrogen, respectively, are presented. *

Jan 1, 1943

By E. C. Truesdale, R. K. Waring

THE Research Division of The New Jersey Zinc Company (of Pa.) has conducted, over a period of years, numerous tests of the reducibility of various zinc ores and the reactivity of various kinds of coal, using a number of different experimental methods. Most of these tests have involved the reduction of mixtures of ore and coal. In such cases the following simultaneous reactions are believed to be mainly responsible for the production of zinc, as was shown by Bodenstein1 some years ago: ZnO + CO = Zn + CO2[I] C + CO2 = 2CO[2]. Each of these reactions is dependent upon the other for the supply of CO and C02, respectively, and the over-all rate of formation of zinc vapor will be determined by the slower of these two reactions. An analogous pair of reactions sometimes of importance is: ZnO + H2 = Zn + H2O[3] C+ H2O=CO+H2[4] While it is possible to obtain an indication of the relative reducibility of various ores, or of a fine versus a coarse ore, by testing them with a given coal, and while coal reactivities may be measured in a corresponding manner, a more direct determination of relative reaction rates is possible by carrying out the desired reactions, such as I and 2, separately and under reproducible conditions. It is one purpose of this paper to present some of the results that have been obtained by the latter method. C. G. Maier2 discusses the relative rates of reactions I and 2 and concludes that while at relatively low temperatures reaction I is faster than reaction 2, this difference becomes less with increasing temperatures, although at smelting temperatures reaction I is still the faster. He also says (p. 48), "At temperatures . . . between 1100° and 1300°C the zinc oxide reduction reaction is intrinsically more rapid than its physical limitations; that is, it is limited by gas diffusion rates." In the course of numerous reactivity tests involving the separate use of reactions and I and 2, we have obtained data that show by direct experiment, we believe for the first time, the correctness of Maier's statements concerning these reactions. We also include data on the relative rate of reaction 3, involving reduction by hydrogen. Finally, some interesting results obtained by carrying out the reduction of a zinc ore-coal briquet in streaming atmospheres of nitrogen, carbon monoxide and hydrogen, respectively, are presented.*

Jan 1, 1941

By Wm. Hamilton Merritt

IN this paper, which I have the honor to submit to the Institute, it is my intention to treat especially of that part of the North Staffordshire field which converges to a long tongue in the neighborhood of Congleton, and which includes the villages of New Chapel, Ford Green, Norton, Biddulph, Bradley Green, Gillow Heath, and the immediate vicinity. My object is not so much to give a minute description of the geology or systems of mining and smelting, as by a general review, some idea of the extraordinary facilities for the production of excellent iron, which have enabled this district to maintain its position more successfully than any of its rivals against the late depression in trade. The North Staffordshire coal field has the Cheshire and Lancashire fields some thirty-five miles to the north, those of Derbyshire and Nottinghamshire forty miles to the east, those of South Staffordshire and Shropshire, about thirty miles to the south, and the Denbighshire and Flintshire fields some forty miles to the west. It is highly probable that the coal continues under the new red sandstone to the Western and Southern fields as the dips on both sides, and absence of large faults, make it impossible to come to any other conclusion. In a section of this coal field, from Chatterly to Whitfield, thirty-two workable seams of coal are shown, of an aggregate thickness of 130 feet, varying from 2 feet 6 inches to 7 feet, and thirteen seams of ironstone, 24 feet, averaging from 2 to 4 feet. All of these seams have been minutely described in a paper by Mr. Charles J. Homer, read in 1875 before the British Iron and Steel Institute. In the northern part, to which I especially wish to direct your attention, the beds lie in a V-shaped basin, the underlying millstone grit and Yoredale rocks rising and forming escarpments on either side of the valley containing the coal. Throughout this district, at the outcrop of the coal, there are indications of old workings. A shaft 4 to 5 feet in diameter reaches the coal at about 14 yards from the surface, and from it the coal has

Jan 1, 1880

By William Hamilton Merritt

In this paper, which I have the honor to submit to the Institute, it is my intention to treat especially of that part of the North Staffordshire field which converges to a long tongue in the neighborhood of Congleton, and which includes the villages of New Chapel, Ford Green, Norton, Biddulph, Bradley Green, Gillow Heath, and the immediate vicinity. My object-is not so much to give a minute description of the geology or systems of mining and smelting, as by a general review, some idea of the extraordinary facilities for the production of excellent iron, which have enabled this district to maintain its position more successfully than any of its rivals against the late depression in trade. The North Staffordshire coal field has the Cheshire and Laucashire fields some thirty-five miles to the north, those of Derbyshire and Nottinghamshire forty miles to the east, those of South Staffordshire and Shropshire, about thirty miles to the south, and the Denbighshire and Flintshire fields some forty miles to the west. It is highly probable that the coal continues under the new red sandstone to the Western and Southern fields as the dips on both sides, and absence of large faults, make it impossible to come to any other conclusion. In a section of this coal field, from Chatterly to Whitfield, thirtytwo workable seams of coal are shown, of an aggregate thickness of 130 feet, varying from 2 feet 6 inches to 7 feet, and thirteen seams of ironstone, 24 feet, averaging from 2 to 4 feet. All of these seams have been minutely described in a paper by Mr. Charles J. Homer, read in 1875 before the British Iron and Steel Institute. In the northern part, to which I especially wish to direct your attention, the beds lie in a V-shaped basin, the underlying millstone grit and Yoredale rocks rising and forming escarpments on either side of the valley containing the coal. Throughout this district, at the outcrop of the coal, there are indications of old workings. A shaft 4 to 5 feet in diameter reaches the coal at about 14 yards from the surface, and from it the coal has

Jan 1, 1880

By Felix Vogel

SINCE the publication of Prof. J. W. Richards's paper on The Schumacher Briquetting Process,2 this process has been in operation on a practical .scale in two plants in the United States, and a few notes on the results obtained may he of interest. An experimental plant, consisting of a toggle press and a hydraulic press, was installed at Johnstown, Pa., together with the necessary bins and other equipment, and an attempt was made to briquette a mixture of Mahoning fines and blast, furnace flue dust, in a ratio of 7 parts of ore to 3 parts of dust. The results were unsatisfactory, in that the briquettes made were not hard enough to stand the severe handling to which they were subjected in the various transferences necessary between the press and the furnace. The trouble was clue to several causes: First, the mechanical arrangement of the plant, which did not lend itself to a proper hardening and loading of the briquettes into the cars. Second, the irregular composition of the flue dust, as to both its lime and its fine coke contents. Third, the variability of the moisture content of the ore, and its viscosity when wet. Fourth, the ratio of fine ore to flue dust; that is, it was attempted to bind in too large a quantity of fine ore for the small amount of flue dust used. The first trouble could be overcome, and has been improved upon in the plant as it stands to-day. The second trouble was important, because of the small amount of dust used as a binder, and might have been easily removed by mixing the flue dust of the different furnaces, which, however, was never done. The third difficulty was more serious, but could have been partly solved, had it been possible to meet this along with the fourth difficulty, by decreasing the percentage of ore in the briquettes. It was proposed to do this, but it seems that the problem at the works in question is, primarily, to prepare Mahoning fines for reduction in the blast furnace, and only secondarily to use up the flue dust, and a solution along this line did not seem to be interesting.

Jan 12, 1913

By J. Campbell

Long freezing range casting alloys are particularly susceptible to a type of porosity which is observed to form in layers parallel to the supposed position of the isotherms in the solidifying casting. Under favorable conditions (which appear to be typified by low-temperature gradients in the casting giving rise to a wide and more or less uniform pasty zone, and which arise from several factors, particularly: a) wide freezing range alloy, b) high thermal conductivity of metal, c) low thermal conductivity of mold, and d) high mold temperature3) layer porosity has been observed in many different casting alloys: copper,' aluminum, magnesium,' steels, and high-temperature alloys.3 Baker4,5 and later cibula6 argue that layer porosity occurs because of thermal contraction, in a manner analogous to hot tearing. In outline, the theory consists of the establishment of a coherent dendrite network by the impinging of dendrite tips. Subsequent shrinkage imposes tensile stresses on the network which tears perpendicularly to the stress, i.e., parallel to the isotherms. If these tears are not filled by the inflow of residual liquid then layers of porosity result. Baker7 attempted to test whether the porosity was the result of thermal contraction by casting test pieces in a mold designed to accentuate hot tearing. However, no significant increase in porosity was observed. This negative result of Baker's critical experiment appears to be substantiated by numerous observations, particularly the experiments by Lagowski and Meier8 on Mg-Zn alloys covering the range of zinc contents up to 30 pct Zn. These clearly reveal that the maxima for the incidence of hot tearing and layer porosity are well-separated, occurring at 1 and 6 pct Zn, respectively. Furthermore, the thermal contraction maximum occurred at 1 pct Zn, indicating that hot tearing is associated with contraction in the solid state, and not with porosity. These observations are further substantiated by the elementary consideration that the thermal contraction of the casting is likely to produce (if anything, since the temperature difference across casting of high thermal conductivity, such as aluminum and copper, is likely to be negligible) a compressive stress on the

Jan 1, 1969

By D. J. Hawthorn

The widespread interest shown during the past year in the study of subsurface pressures warrants brief reference to its early development. Though it is impossible to set an exact date when constructive thinking on the subject first began, nevertheless, evidence is available that thought was given to the problem as far back as 16 or 1.7 years ago. There is record in one of the foreign journals of actual subsurface tests made by crude methods in one of the Rumanian fields in 1918 and 1919.' These tests were performed in conjunction with studies made on wells produced by bailing and, incidentally, the final outcome of the work led to the development of the so-called "duplex bailer" which is reputed to have trebled volumetric bailing efficiency. From this time on to 1927 a few scattered bottom-hole pressure determinations were made with makeshift instruments of one form or another, but probably not until 1927 was any great amount of concerted effort directed to the subject. At this fall meeting of the Petroleum Division four years ago was presented one of the first papers2 to appear in this country written for the express intent of advocating the value and importance of subsurface pressure determinations. It is thought to have been the first to present direct data on subsurface pressures obtained through the use of a specially designed recording instrument. As might be expected, the instrument had its limitations, but reasonably accurate results were obtained and, to say the least, it constituted a progressive step in the right direction. During the period from 1927 to 1931, many noteworthy improvements were made in the design and perfection of subsurface pressure instruments suitable to meet all conditions. Because of the magnitude of this task much credit is due the men who pioneered this work. They should feel a keen sense of satisfaction in the thought that their efforts have paved the way for the continuation of this most valuable study. At the present time more than a dozen companies are operating subsurface pressure instruments in the Mid-Continent field. Engineers in

Jan 1, 1933

By Gerald Sherman

In the southern field of the anthracite region of Pennsylvania, many of the coal seams dip at angles of 40" to 50" from the horizontal. For transportation purposes, "tunnels" are driven across the coal measures and, occasionally, "rock gangways," beside the seams and parallel with them. The use of gangways driven in country rock appears to be increasing, as they avoid the maintenance of long gangways in coal, which eventually are driven to the colliery boundaries, and permit mining from a number of intermediate blocks without interference. The rock consists of slates or sandstones of moderate hardness, which may range into very hard, highly siliceous, fine-grained conglomerates. In this distinctly bedded formation, the direction of the heading, whether parallel with or across the structure, makes it necessary to distribute the drill holes in a different pattern to break the ground, but does not change loading conditions. In 1932, practically all the mucking was done by hand, and it was the established custom to use four men on two drills for drilling and breaking the ground, and five for loading it out. A driver and mule was needed in addition, to assemble the rock cars at a siding or branching track in the rear, pending their final disposal. This might occupy the driver's whole time, or if the length of haul were short, he might be able to do other useful work. It was thought possible in 1932 to reduce the cost of driving such headings in rock by mechanical loading, and to investigate this subject a scraper loader was used in a section of tunnel then being driven. Operations while driving 195 ft. of this tunnel using a scraper loader were carefully observed. Time studies were made of the loading, and records made of the routine of breaking ground, but not in such detail. Tunnels or gangways in the colliery are 7 ft. high above the rails, by 10 ft. wide, which requires a minimum of 8 ft. in height, broken to allow for rails and ties. This cross section is of sufficient size to permit the use of any one of several types of power loaders, but for this demonstration it was found most convenient to use a scraper loader.

Jan 1, 1937

By A. B. Hildebrandt

P. B. Baxendell is to be complimented for an exccllent piece of work. To our knowledge there has been no previous publication of field data on the flow of oil and gas through the annulus of a well. It is certainly gratifying to see this work on annular flow confirm the previous published correlation procedure on tubing flow. It extends considerably the range under which reliable gas-lift calculations can be made. Baxendell discussed this work with us about a year ago and was kind enough to send a large scale plot of his correlation. We had been designing gas-lift installations on flow through the annulus, assuming that the original correlation of the f factor based on tubing flow' was valid as long as we stayed within the same mass velocity range on which the correlation was based. Doing this work necessitated the use of an equivalent diameter for the annular flow. The equivalent diameter is defined as area' of stream cross section wetted perimeter and for the case of an annulus is D, — D,. Substituting this in the basic equation correlating energy loss along with the area to flow required to convert the velocity, to volumetric flow rate, D (Baxendell's Eq. 7) becomes dell's expression, D,). Similarly, the D in 1.4737 X 10 (M&/D) becomes (D, + D;) for annular flow. On receipt of Baxendell's data, we. of course, recalculated it to put it into the form we were using, and to see how well it agreed with the correlation based on tubing flow. Fig. 1 shows the results, which were certainly gratifying. For low values of (D, - D,) pv, the data coincide with the data on flow through tubing, whereas at high values the data on flow through the annuli appear to be leveling off to a constant value. For very high rates of flow where the turbulence is very high, one might expect the value f to level out and become constant. A bulletin published in 1914 by the U. of Wisconsin presented results of a large number of laboratory teats in air lifting water through short lengths of 1.25-in. tubing. It was possible to correlate a random sampling of

By Gerald Sherman

IN the southern field of the anthracite region of Pennsylvania, many of the coal seams dip at angles of 40° to 50° from the horizontal. For transportation purposes, "tunnels" are driven across the coal measures and, occasionally, "rock gangways," beside the seams and parallel with them. The use of gangways driven in country rock appears to be increas-ing, as they avoid the maintenance' of long gangways in coal, which eventually are driven to the colliery boundaries, and permit mining from a number of intermediate blocks without interference. The rock consists of slates or sandstones of moderate hardness, which may range into very hard, highly siliceous, fine-grained conglomerates. In this distinctly bedded formation,' the direction of the heading, whether parallel with or across the structure, makes it necessary to distribute the drill holes in a different pattern to break the ground, but does not change loading conditions. In 1932, practically all the mucking was done by hand, and it was the established custom to use four men on two drills for drilling and breaking the ground, and five for loading it, out. A driver and mule was needed in addition, to assemble the rock cars at a siding or branching track in the rear, pending their final disposal. This might occupy the driver's whole time, or if the length of haul were short, he might be able to do other useful work. It was thought possible in 1932 to reduce the cost of driving such headings in rock by mechanical loading, and to investigate this subject a scraper loader was used in a section of tunnel then being driven. Opera-tions while driving 195 ft. of this tunnel using a scraper loader were care-fully observed. Time studies were made of the loading, and records made of the routine of breaking ground, but not in such detail. Tunnels or gangways in the colliery are 7 ft. high above the rails, by 10 ft. wide, which requires a minimum of 8 ft. in height, broken to allow for rails and ties. This cross section is of sufficient size to permit the use of any one of several types of power loaders, but for this demonstration if was found most convenient to use a scraper loader.

Jan 1, 1936

By A. M. Tweedy, Felix A. Vogel

Since the publication of Prof. J. W. Richards's paper on The Schumacher Briquetting Process,' this process has been in operation on a practical scale in two plants in the United States, and a few notes on the results obtained may be of interest. An experimental plant, consisting of a toggle press and a hydraulic press, was installed at Johnstown, Pa., together with the necessary bins and other equipment, and an attempt was made to briquette a mixture of Mahoning fines and blast-furnace flue dust, in a ratio of 7 parts of ore to 3 parts of dust. The results were unsatisfactory, in that the briquettes made were not hard enough to stand the severe handling to which they were subjected in the various transferences necessary between the press and the furnace. The trouble was due to several causes: First, the mechanical arrangement of the plant, which did not lend itself to a proper hardening and loading of the briquettes into the cars. Second, the irrrgular composition of the flue dust, as to both its lime and its fine coke contents. Third, the variability of the moisture content of the ore, and its viscosity when wet. Fourth, the ratio of fine ore to flue dust; that is, it was attempted to bind in too large a quantity of fine ore for the small amount of flue dust used. The first trouble could be overcome, and has been improved upon in the plant as it stands to-day. The second trouble was important, because of the small amount of dust used as a binder, and might have been easily removed by mixing the flue dust of the different furnaces, which, however, was never done. The third difficulty was more serious, but could have been partly solved, had it been possible to meet this along with the fourth difficulty, by decreasing the percentage of ore in the briquettes. It was proposed to do this, but it seems that the problem at the works in question is, primarily, to prepare Mahoning fines for reduction in the blast furnace, and only secondarily to use up the flue dust, and a solution along this line did not seem to be interesting.

Jan 1, 1914

By W. W. Gorr, R. Smith, E. H. Wyche

THE combination of high strength and corrosion resistance of cold-worked 18 Cr, 8 Ni steel has been advantageously utilized for some time, particularly in aircraft and rail car structures. There are, however, certain limitations on the use of such materials because the high strengths can be obtained only by cold-working, limiting the available products to sheets, strip, wire and tubes. The authors sought to overcome these limitations by resorting to precipitation-hardening, which has been used so successfully in nonferrous metallurgy but only to a limited extent in iron-base alloys. Accomplishment of this objective not only overcame the limitations, but also effected certain improvements in mechanical and other properties. This paper is an account of the development by Carnegie-Illinois Steel Corporation of a precipitation-hardening 18-8 stainless steel (called Stainless W? and tentatively identified as type 322). A description is given of its composition and metallurgical characteristics, heat-treatment, physical and mechanical properties and corrosion resistance. DEVELOPMENT OF THE NEW STEEL For a considerable length of time the authors were unable to determine the mechanism of the precipitation-hardening process that had been noted by Ffield 18,19 in 18-8 Ti or 18-8 Cb after cold-working and reheating to moderately elevated temperatures. All known variables were exhaustively studied, but with little success. However, results began to indicate that chemical composition was the most important variable, particularly the ratio of austenite-forming to ferrite-forming elements. The investigators 'then focused their attention upon the composition, and, in particular, upon the element titanium and its mode of alloying in the presence of other elements. A heat was obtained that could not be brought to the softness level of annealed 18-8. The response to cold-straining and aging* was very marked by previous standards, and, more important, cold-straining was found to be entirely unnecessary to produce the precipitation-hardening effect. The chemical composition of this heat was: C, 0.06 per cent; Mn, 0.54; P, 0.016; S, 0.016; Si, o.58; Ni, 7.28; Cr, 17.6o; Ti, 0.90; Al, 0.17. For some time the development work, particularly on composition, was carried

Jan 1, 1946

By Rodney P. Smith

THE solubility of columbium nitride in ? iron has been determined for the temperature range 1191o to 1336°C from the nitrogen content and metallogra-phic examination of a series of Fe-Nb alloys.* (0.0 to 0.92 pct Nb) equilibrated with a purified gas mixture of 1 pct hydrogen in nitrogen. The method is the same as that used by Darken, Smith, and Filer' to determine the solubility of aluminum nitride in y iron. The variation in the furnace temperature during an equilibration period was about ± 2.0°C. Each sample was approximately 1/2 in. wide, 2 in. long, and 1/16 in. thick. A time series at 1200°C using samples of highest columbium content indicated that one day was sufficient for equilibrium; however, to be on the safe side all samples were left in the furnace for either two or three days. Afterequilibration, the samples were brought to room temperature by quenching in water. The experimental results are shown in Fig. 1. To be in accord with the values reported by Wriedt and Gonzalez2 and the temperature coefficient of our results at higher temperatures, the nitrogen content of iron at 1191oC is assumed to be slightly lower than our experimental value. Our data for the single-phase regions are not sufficiently accurate to establish an interaction coefficient for nitrogen in these alloys. However, the change in nitrogen content with change in alloy content for a number of systems (Fe-N-A1;3,1 Fe-N-Ni;372 Fe-N-Si.3949 Fe-N-V;3,5 Fe-N-Cr;3,6 Fe-N-Mo3,7) has practically the same value for the liquid alloy at a temperature near 1600°C as for the solid alloy at temperatures near 1200oC when the alloy content is below a few percent. On this basis the lines through the single-phase regions have been drawn with a slope corresponding to an increase in nitrogen of 0.0013 pct per 0.1 pct Nb.3 The straight lines through the two-phase regions were drawn with a slope corresponding to a one-to-one atom ratio of nitrogen to columbium in the nitride. The X-ray

Jan 1, 1962