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By C. S. Smith

QUANTITATIVE methods were used to good effect in the earliest days of metallography1-3 but they mysteriously passed into virtual disuse until the important paper4 by Howard and Cohen in 1947. Various devices for the measurements of integrated linear intercepts have been constructed, primarily by petrographers. The hydraulically operated stage designed by the writer5 was satisfactory, but prolonged use caused air bubbles to become entrapped, which introduced back-lash. A new stage has been constructed which avoids this defect and provides better integration when measuring directional structures. This utilizes a circular traverse, and integration is achieved by counting electrical pulses produced by a photocell and a light chopper.* The stage is shown diagramatically in Fig. 1 and in photograph, Fig. 2. It is of simple construction. Mounted on a plate with clamps to fit the stage of a standard metallurgical microscope is a worm and 100-tooth worm gear, the latter supporting the specimen to be measured. The worm is manually actuated by a knob which contains inside it three

Jan 1, 1961

By John Langton

In determining what kind of pourer should be adopted for the works of the Moctezuma Copper Co. at Nacozari, Sonora, Mexico, certain considerations imposed by local conditions had to be taken into account. Water.—During most of the year the water-supply is abundant for all purposes, but it dwindles rapidly when the dry season sets in, reaching a minimum flow which is entirely undergrouad. It was evident, that with the greatest care in keeping down the unavoidable loss of water in milling and smelting, these operations and hence the capacity of the works mould ultimately be limited for about two months of the year by the small watersupply available at the period of minimum flow. Transportation.—The nearest railway terminus was in Arizona, at the international boundary-line; and the price of supplies at that point would be enhanced at Nacozari by the additional cost of a 90-mile wagon-haul. During the rainy season, transport to Nacozari was much impeded, and at times made impossible, by the condition of the roads. Hence, to insure continuous operation at the works, it would be necessary to provide for hauling the year's supplies, including fuel for power and coke for smelting, in less than eleven months. In other words, the average freight delivered daily at the works should be at least 10 per cent. more than the average daily consumption. For moderate quantities of freight, pack-carriage by burros is astonishingly cheap. But it has a capacity-limit which is generally very soon reached. A 200-lb. load, and 10 miles a day, 5 with and 5 without load, is the full capacity of a burro. This means one burro per ton-mile of the round trip; and,

Jan 1, 1904

By JOHN R. SUMAN

IT appears now that the conflict with the totalitarian states will be a long-drawn-out struggle. The course of this war up to now indicates that this may well be the first major conflict where man power has not been the vital and determining factor. Mechanized warfare has made it possible for relatively small, well-equipped groups to outmaneuver and defeat large armies which lack the necessary modern equipment. Under these circumstances, ultimate victory becomes a matter of resources and productive ability. The important question is not how many soldiers can he put into the field, but the volume and speed in producing the armaments essential to ensure a victory. The resources available to the opposing nations and the efficiency of their systems of enterprise and production will be primary factors in determining the ultimate outcome. Germany had a head start of eight years in the armament race, and it is not easy to overcome such an advantage overnight.

Jan 1, 1942

By Karl A. Bauer, Cornelis Bezemer

The deposition of calcium carbonate scale on surface and subsurface production equipment creates an operation problem in many oil fields. The formation water in which the carbonate-scale-forming components are initially dissolved becomes supersaturated with calcium carbonate as a result of the drop in pressure during production. The continuous flow of a supersaturated solution through the production equipment results in the growth of a dense layer of calcium-carbonate crystals. For a scale layer to be built up, the supersaturated formation water should contact the walls of the production equipment. The tendency for scale to be deposited, therefore, will be low, if the crude has a low water cut and if the water is finely dispersed in the oil. A scale problem will occur, if at a high water cut part of the water is present as free water. The rate of scale deposition will then be approximately proportional to the rate of free water production. Depending upon where the formation water becomes supersaturated, scale may be deposited in the flow line only, in both flow line and tubing, and in some cases even in the perforations and in the formation near the wellbore. In the South Sumatran fields (Indonesia) the main difficulties encountered due to the deposition of calcium-carbonate scale have been restriction of flow through tubings and flow lines, wear and abrasion of plungers and liners, and stuck plungers or wellhead valves. So far, the only methods of combating the *Presently associated with Brunei Shell Petroleum Co., Ltd.. Seria. scale problem have been routine acidizing and additional well pulling. As for the pumping wells, it was estimated that some 50 percent of the total well-pulling effort was directly attributable to scale deposition. The most promising alternative was to prevent the deposition of calcium carbonate scale by means of chemicals. Inorganic polyphosphates such as sodium hexametaphosphate and trisodium polyphosphate are known to retard the formation of scale by the "threshold action". They are adsorbed on specific faces of the crystal nuclei and thus prevent crystal growth, thereby stabilizing supersaturation. Polyphosphates are effective at very low concentrations ( a few ppm), and far less than stoichiometric quantities are required to keep the scaling ions in solution. Recent investigations on barium sulfate scale1 have confirmed this mechanism. The types of polyphosphate mentioned can be applied as concentrated aqueous solutions either squeezed into the formation, lubricated down the annulus or injected via macaroni string. Several squeeze jobs with polyphosphate solutions have been carried out in the South Sumatran fields, however, with disappointing results. Lubrication down the annulus and injection through a macaroni string were not considered attractive in this area because of the kind of equipment and the degree of supervision these techniques require. Polyphosphates are also available in a granular, glassy form, which, in contrast with the readily soluble types already mentioned, show an extremely low

Jan 1, 1970

By W. V. Long, D. H. Reynolds, R. B. Bhappu

Equilibrium distribution coefficients were determined for some monovalent and polyvalent ions for several absorbing and exchanging media as functions of pH and initial ion concentration. Among ions studied were NH4 (I), K(I), Ni(II), Ce(III), Th(IV), and Mo(VI). Absorbents used were: ion exchange resins; a tertiary, and a quaternary amine in an inert solvent; and some activated carbons. The ions studied were in aqueous HCI, HNO3, H2SO4, or HC104 solutions. The classical mass action expression proved of little value in describing the variations observed. The data indicate that the determining factors in absorption and ion exchange may be the ionic species in the aqueous solution, which in turn depend upon pH, dilution, and perhaps other conditions. Three sorption processes have become prominent in recovering values from leach solutions. These are: 1) ion exchange, 2) solvent extraction (liquid ion exchange), and 3) physical adsorption by materials of high specific surface. In the first two of these processes the exchange reaction is considered chemical in nature, and is discussed in terms of the mass action principle. The third is considered a surface phenomenon and is discussed in terms of surface areas and various forms (Gouy, Stern, Grahame, etc.) of the Helmholtz double-layer theory. Generally speaking, we have found in chemical analysis and hydrometallurgical studies that there are close similarities between the three sorption processes, and also differences which are difficult to reconcile with any of the usual theoretical treatments. That others have experienced the same troubles is shown by the fact that usable processes, in chemical analysis as well as in hydrometallurgy, generally are discovered by empirical procedures. EXPERIMENTAL CONSlDERATlONS The gaps between theory and practice have allowed many conflicting statements to appear in the litera- ture. To learn, in particular, the behavior of some metallic ions on a cation exchange resin at a constant pH, equilibration studies were made over a wide range of concentrations.' Results are shown in Fig. 1 for four metals in hydrochloric acid solution on a strongly acidic cation exchange resin, AG 50W-X8 (Bio-Rad). The distribution coefficient, defined as D = amount of metal extracted per g of resin/amount of metal unextracted per ml of solution is seen to vary in a way to support all manner of reports about its behavior with changes in solution concentration. The metals used were chosen from those least likely to form stable chloro-complexes. The changes of slope in the various isotherms may reflect formation of unsuspected chloro-complexes of low stability (ion-pairing for example) whose concen-

Jan 1, 1967

By AIME AIME

THE stage is set for the 1930 Annual Meeting. It will take place in the Engineering Societies Building. Feb. 17, 18, 19 and 20, and an unusual pro- gram of technical papers, symposia, lectures and addresses, interspersed with luncheons, dinners, excursions and worthwhile entertainment for the four days has been arranged. The curtain rises on Monday morning and the first act is by the entire company-registration. Then the meeting hits its stride, for there are ten technical sessions on Monday, and the range of subjects includes most of the Institute membership. The Committee on Coal and Coal Products, which is about to become the Coal Division, presents a symposium of a dozen or more papers on Coal Classification, concluding its afternoon session with several papers on general subjects. At its luncheon between sessions, C. E. Bockus, president of the National Coal Association, will be the honored guest. Papers of theoretical character will be discussed at the morning session of the Committee on Geophysical Prospecting; at its afternoon session there will be presented summaries of results obtained at various properties by methods described at previous meetings of this group and permanently recorded in "Geophysical Prospecting," published by the Institute early in 1929. Members of the Petroleum Division should not overlook the paper by Theodor Zuschlag, on this Committee's program. It is entitled, "Oil Structure Mapping by the Sundberg Method." Members of the Iron and Steel and Institute of Metals divisions will find it profitable to attend the session on Engineering Education on Monday afternoon. E. A. Holbrook has arranged a program of ten-minute talks on Metallurgical Education which are designed to get down to "brass tacks." and the practical man may, in discussion, contribute as well as learn. At 5 p. m. Thomas T. Read will lecture+ at Columbia University, on "Recent Progress in Economics of the Mineral Industries."

Jan 1, 1930

By G. C. Stone

IN common with many members of the Institute, I was much interested in Mr. Kent's paper on " Manganese Determinations in Steel," * read at the Virginia meeting. Having recently had an opportunity to collect a similar series of results for spiegel, I venture to offer them to the Institute, hoping that they may also prove of interest. Sample No. 1 was taken at our works, where the spiegel was made,

Jan 1, 1883

Organization Place Date 1917 American Electrochemical Society Pittsburgh, Pa. Oct. 3-6 American Institute of Mining Engineers St. Louis, MO. Oct. 8-13 American Gas Institute : Washington, D. C. Oct. 16-19 American Institute of Architects Philadelphia, Pa. _ Dec.. 26-29 American Society of Mechanical Engineers New York City. Dec. 26-29 American Mining. Congress State Chapter Phoenix, Ariz. Dec. 26-29

Jan 10, 1917

By Albert F. J. Bordeaux

The immediate vicinity of the sea-shore, affording special facility for the exportation of ores, makes it possible to work certain mines in the Vladivostok district, which, in more remote places of Siberia., would remain unproductive. Outside of the city of Vladivostok the population is small and the country is very little prospected. Additional discoveries of valuable deposits like the large body of calamine which has recently been opened in the neighborhood of earlier worked lead-silver ores, in the Tetiuhe valley, are still in the field of possibilities. For many years gold alone was produced, in part from the coastal rivers and in part from a quartz-vein on Askold island near Vladivostok. But the production is diminishing, and prospectors are looking for other rivers in the interior, such as the tributaries of the Ussuri. These rivers are now more accessible than formerly, due to the slow but gradual development of colonization by the Russian peasants. The few natives of the country, called Orodjones, are of the Chinese race. They resemble the North American Indian and are hardy fur-hunters. They have given some attention to placers and have already shown good specimens of gold-dust from the rivers Iman, Bikin, Noto, etc. Coal-mining was begun in the Vladivostok region more than 20 years ago, but in a somewhat irregular way. The industry is not as yet important and the best coal-seams are badly prospected, or are even neglected. Copper, lead, and iron exist in several places. The amounts give some encouragement to the anticipation that the discoveries will give rise to important metallurgical works. I here present a review of the various deposits, based upon such safe information as is in hand, when I have not drawn upon my personal observations. Fig. 1 is a map of Eastern Siberia, showing the mineral deposits.

Jan 1, 1913

By . M. Muskat

A THEORETICAL consideration of the mechanics of various water-flooding systems with the viewpoint of comparing their relative merits involves the study of two fundamental properties of such systems. On the one hand, it is important to determine the efficiency of the flood as measured by the percentage of the total area that is swept out by the encroaching water before water actually reaches the output wells. This is really a measure of the regional tendency of the water to "bypass" the oil. On the other hand, the various systems must be compared from the viewpoint of their resistances which determine the rate of fluid production obtainable for given pressures maintained at the water input wells. The first of these questions has been studied and very definite answers have been obtained by means of simple electrolytic models.1 These models showed that, in an ideal system, the percentages of the areas flooded out before water reaches the output wells are about 57 per cent for the direct line-drive flood (the input and output wells being equally spaced and placed in alternate parallel lines), 74 per cent for the regular five-spot network, and 79 per cent for the seven-spot network. With respect to the efficiency of the usual flooding arrangements, they are, therefore, given quite accurately by the above numbers. With regard to the resistances of the flooding networks, electrical conduction models have also been used successfully2 and are well adapted to the problem of determining experimentally the pressure distribution and streamlines, or over-all resistances of specific flooding networks. However, such models do not permit readily a study of the effect of changing dimensions or configuration within a network, since a new model must be made up for each set of dimensions considered.

Jan 1, 1933

By W. H. Brandt

THERE has been much progress in the last two decades in understanding the hardenability of steel. Roughly, the progress has been along two lines, which may be designated as empirical and fundamental. This empirical work has progressed to the point where steels may be manufactured to the desired characteristics quite closely and heat-treatment and application problems can be approached with considerable confidence. Particularly noteworthy among the empirical work is that of Grossmann,12 who has given formulas for calculating hardenability as a function of composition, and the establishment of the isothermal transformation curve by Davenport and Bain.13 The latter does not fall entirely in the class of an empirical study, for while it provides a means of presenting a tremendous amount of empirical data in the form of a single curve, it also outlines clearly the problems that face the fundamental investigator. The isothermal transformation curve shows clearly that the phenomena occurring in the neighborhood of the knee of the curve are those that limit the hardenability of steel. Above the knee of the curve, the product of decomposition of austenite is lamellar pearlite and fundamental progress has consisted chiefly of a detailed study of structure and formation of pearlite, largely at the hands of Mehl and his collaborators.1-5 They have shown that formation of pearlite proceeds by a process of nucleation and growth and they measured both the nucleation and growth rate. However, there is still a wide gap between our empirical knowledge and fundamental knowledge, owing largely to the fact that there is no satisfactory theory of nucleation rate or of growth rate. This paper is being written in an attempt to fill in a small part of the gap. A method was presented recently14 for calculating the velocity of edgewise growth of pearlite using an expression for the carbon concentration that satisfies the diffusion equation. The edgewise velocity of pearlite growth in a plain carbon eutectoid steel was calculated, using linear extrapolations of the ferrite and cementite solubilities. While the results are in fairly good agreement with the experimental facts, the calculated velocity of edgewise growth is smaller at 600°C. than G, the radial growth velocity of pearlite nodules, whereas one would expect it to be larger. In this paper the calculation will be repeated using a new extrapolation for the ferrite solubility, which gives better agreement between G and V, the calculated velocity of edgewise growth. A calculation will also be made of the effect of carbon content on velocity of edgewise growth, and the problems of calculating the effects of other alloying elements on growth rates will be discussed. It will be assumed that the mechanism of pearlite growth, established by Mehl and

Jan 1, 1945

By C. M. White

CITIZENSHIP is a rather abstract subject on which a great deal could be said-a subject on which a great deal is said -and still one which too many of us seldom think about and seldom work at. Too many of us engineers and business men have but a vague idea of citizenship. We think that if we go to the polls on election day and obey the laws scrupulously, with the exception of an occasional traffic violation, we are pretty good citizens and are doing our duty by our city, state, and nation. But when you think it over, that's a very passive observance of the important right of counting oneself a citizen of a country. There is nothing very positive in that attitude. There is nothing that indicates that we have sufficient interest to really go out and do a job for the -welfare of our country, forgetting any personal advantages or inconveniences that might arise. In other words, this type of voting-on-election- day, law-abiding citizenship does not keep us awake a single minute; it does not take any particular thought or require the expenditure of any time or energy.

Jan 1, 1939

By Philip B. Bucky

WITH the exhaustion of the sections of iron ore bodies amenable to opencut mining the iron ore miners raise the question: "How can we mine the extensions of these ore bodies in depth with the same costs as obtained in opencut work?" This question brings to the fore the relationship between mineral exploration and research on mining procedures. The iron miners must either find new de? posits amenable to their known methods of mining or develop new mining methods for deep deposits. It is understood that the oil companies will spend $30,000,000 next year in the search for new oil fields. How much the metal mining companies will spend in the search for new ore bodies is unknown, but without doubt the amount will run into several millions of dollars. If the mining companies that concern themselves with metals, nonmetallics, and fuels will set aside a substantial sum for fundamental and applied research in mining methods, they can not only lower their costs but increase their reserves thereby. Any increases in mining efficiency automatically result in increased ore reserves at no cost.

Jan 1, 1947

By C. H. Mathewson

ABOUT fifty pages of Henry M. Howe's profound treatise, "The Metallography of Steel and Cast Iron," are devoted to twinning with special reference to the origin, nature and general significance of the Neu-mann bands in ferrite. Howe believed with Osmond and Cartaud1 that the Neumanns are mechanical twins and his careful observations leave no doubt that these straight-sided narrow bands habitually occur parallel to trapezohedral planes of form {211}. Attempts to develop the structure of the bands by various methods so that their identity could be established beyond question have not been conspicuously successful. Howe thought that they deflected slip bands. Some of the etching figures which have been developed within and adjacent to Neumann bands support the contention that they are twins. A good example of this effect in ferrite containing 0.6 per cent. of nickel and 1.3 per cent. of phosphorus, originally due to Harnecker and Rassow,2. was reproduced in the 1928 lecture before the Institute of Metals Division on twinning in metals.3 In this case, the sides of the figures might represent the traces of cubic planes laid bare by etching a properly oriented grain of ferrite, twinned along a plane of form 12111. Our own observations in this direction may be represented by Fig. 1 which shows in a deeply etched cavity in the boundary region between a Neumann band and the original crystal two small crystal surfaces which resemble the faces meeting at a reentrant angle in the simple cube twinned along a bisecting plane of form {211} as sketched in Fig. 2. Rosenhain and McMinn4 in 1925, after a careful study of slip bands in ferrite containing Neumanns previously produced by shock, concluded

Jan 1, 1928

By R. S. Archer

BERYLLIUM has certain properties such as low density, high hardness, good corrosion resistance, low thermal expansion and fairly good electrical conductivity, which would indicate that it, is worthy of consideration as an ingredient of light alloys. It was not until recently, however, that beryllium could be produced with sufficient ease to encourage research along this line. The production of beryllium by electrolysis from a fluoride bath has now developed to the stage where it could be used commercially if there were sufficient demand for the element. Claims made in certain newspapers and technical articles in regard to the strength and corrosion resistance of the aluminum-beryllium alloys are not justified by experimental results. Moreover, beryllium is an expensive metal ($200 a pound at the time this work was done) and, on account of the nature of its ore and the consequent difficulty of its extraction, it will in all probability continue to be a relatively expensive metal, although the cost would undoubtedly be a great deal less than $200 a pound if the metal were produced on a large scale. It seemed, therefore, that low-beryllium alloys offered the greater commercial possibilities except for very special purposes. It was partly for this reason that in the present work emphasis has been placed on beryllium alloys of low beryllium content.

Jan 1, 1928

By Thomas L. Kesler

I all of the 14 million tons of kaolin produced in Georgia through 1949 had been mined from a single deposit 20 ft thick, it would represent a mined-out area of less than 1 sq mile. This measure of depletion is in such strong contrast with the large size of the area shown in Fig. 1, from which most of the output has come, that there has developed an optimistic outlook concerning future supplies of kaolin equal in grade to that already mined. Dozens of mines are widely but not evenly distributed within this area, which consists mostly of parts of Twiggs, Wilkinson, and Washington counties. There are scarcely half a dozen kaolin mines elsewhere in the state that have been appreciably productive, although the areas in which they occur may have good possibilities. Most of the efforts to find new deposits, therefore, will be confined to the area shown in Fig. 1, for it is here that the industry has established its facilities, and prospecting is encouraged by relatively numerous outcrops and opened deposits of kaolin. The Ocmulgee and Oconee rivers drain the area. They and their main tributaries have flat, swampy floodplains covered with alluvium and for the most part thickly wooded. The divides between these streams are intricately dissected by the minor tributaries, which are spring-fed in steep-walled, cirque-like heads. Gullying and under-cutting are active along the streams but are partly controlled by unusually dense vegetation. The mean altitude is about 350 ft above sea level, and locally the relief ranges up to 200 ft. The area is near the inner margin of the Coastal Plain, and is underlain by Cretaceous and Tertiary formations. Its general location is shown in black in Fig. 1. The division between the Coastal Plain and the Piedmont plateau is actually a very sinuous line, the fall line, marking the extent to which erosion has stripped the Coastal Plain sediments from the southeastward-sloping surface of the crystalline rocks of the Piedmont. Cretaceous Host Formation The kaolin deposits, which are described in the succeeding section, occur sporadically in lenslike bodies in a thick series of poorly sorted clayey sands constituting the lowermost of the Upper Cretaceous formations, the Tuscaloosa. The basis for this correlation has been reviewed by Cooke.1 The same formation has been termed the Potomac group by Ladd2 and the Middendorf formation by Smith' in reports on the kaolin deposits. In another report, Veatch4 called the formation the Tuscaloosa but correlated it with the Lower Cretaceous. The Tuscaloosa in this area consists of fine to very coarse sands, commonly cross-bedded, which contain widely different proportions of white, pink, and yellow kaolin and considerable white mica. A few of the coarser beds contain quartz grains up to 3 in. in length, with bodies of pure white kaolin of equal size that appear to have been formed by the weathering of feldspar grains in place. In the kaolin-producing area, gravel and cobbles occur mainly at the base of the formation. Fig. 2 shows the relations of the Tuscaloosa and its kaolin deposits to the adjacent formations. Its base, on the eroded surface of the crystalline rocks, dips southeastward 50 to 60 ft to the mile, according to LaMoreaux.5 The upper surface of the Tuscaloosa is also an unconformity,

Jan 1, 1952

By T. W. Atkins

ATHOUGH the magnesium industry in this country is about thirty years old, not until American industry began to amaze the rest of the world and confound our enemies with the extent and variety of our war production did the industry begin to come into its own. At the outset of the war, only three companies were producing and fabricating magnesium in this country. Today, about sixty companies are producing, casting, forging, extruding, rolling, and stamping this lightweight champion of metals. Experience in alloying, processing. and fabricating the metal gained during the war years is now being translated into hundreds of civilian peacetime applications. In no sense should magnesium be considered as a substitute for other metals. It has come into popular favor because If many unique properties in addition to is being the lightest known structural metal. These attributes are toughness, igidity, corrosion-resistance, and the ease with which it can be machined and worked. Magnesium is the third most abundant element in nature. Sea water, magnesite,

Jan 1, 1946

By GEO H. DEIKE

NOT much activity has been evident during the past year in the establishment of co-operative scholarships but the interest among the coal-mining companies is more pronounced than ever. This is apparent from the replies received to a letter sent out by the Committee on the Promotion of Student Interest in Coal Mining to over 120 coalmine operating officials. With that letter was forwarded a bulletin issued by the school of mineral industries of The Pennsylvania State College entitled ?Industrial Scholarships ? a Partnership of Industry and Education.? In that circular was outlined the need for trained men in the war and postwar world, and particularly as such demands pertain to the growth of the mineral industries.

Jan 1, 1943

By Thomas L. Kesler

IF all of the 14 million tons of kaolin produced in Georgia through 1949 had been mined from a single deposit 20 ft thick, it would represent a mined-out area of less than 1 sq mile. This measure of depletion is in such strong contrast with the large size of the area shown in Fig. 1, from which most of the output has come, that there has developed an optimistic outlook concerning future supplies of kaolin equal in grade to that already mined. Dozens of mines are widely but not evenly distributed within this area, which consists mostly of parts of Twiggs, Wilkinson, and Washington counties. There are scarcely half a dozen kaolin mines elsewhere in the state that have been appreciably productive, although the areas in which they occur may have good possibilities. Most of the efforts to find new deposits, therefore, will be confined to the area shown in Fig. 1, for it is here that the industry has established its facilities, and prospecting is encouraged by relatively numerous outcrops and opened deposits of kaolin.

Jan 10, 1951

By W. F. Campbell

One of the deepest coal operations today is the Springhill No. 2 mine of Cumberland Railway & Coal Co., subsidiary of Dominion Coal Co. Ltd. Mining is now conducted at a slope distance of 14,000 ft, with 4400 vertical ft of cover. The record of Springhill No. 2 can be said to contain the history of bumps in the Province of Nova Scotia. The Springhill coal field forms part of the Cumberland field of Carboniferous age. There are seven mineable fields in the area, numbered in the order they were discovered. Mining has been carried on in all but the No. 4 and 5 seams, but present operations are confined to the No. 2. Fig. 1 shows a vertical section through the seams. Opened in 1873, No. 2 mine was first worked from parallel slopes driven from the outcrop of No. 2 seam down to the 7700 level. As the mine went deeper, a two-place auxiliary slope was driven from the 6900 level to the present workings. A transfer level at the 7800 connects the main haulage with the auxiliary haulage slope. The No. 2 mine plan is shown in Figs. 2 and 3. The seam is bituminous, averaging 8.5 to 9 ft thick. There is a well defined parting 14 to 16 in. from the roof, and this roof coal is harder than the rest of the seam. Average pitch at the outcrop is 30°; at the 6500 level, 20°; at the 7900 level, 16°; and at the 13,800 level, 10°. Immediate roof and floor strata consist of beds of variable thicknesses of shales, grading to arenaceous shales to shaly sandstones to sandstones. A characteristic of the strata is the appearance and disappearance of sandstone bands, of considerable thickness, over distances of several hundred feet. MINE HISTORY Entrance to No. 2 mine is obtained by three parallel slopes, separated by 100-ft pillars except in the upper portion of the mine where the pillars are smaller. Main haulage levels were originally driven 600 ft apart for room and pillar extraction. A parallel drainage and intake airway was driven below each haulage level and a parallel return airway (counter level) above. Pillars 80 to 100 ft wide separated these two servicing entries from the center haulage level. Inclines up to 700 ft apart were driven off the levels up pitch to the upper levels, and at 40-ft centers level rooms 12 ft wide were driven off each side of the inclines, separated by crosscuts every 50 to 100 ft. The rooms were driven up to 350 ft or until they were holed into the room from the adjoining incline—a plan followed until the level reached its boundary. When the entire area between two levels had been divided into pillars, the pillars were extracted from the boundary back to the slope pillars. As depth of cover increased, mining conditions required larger pillars, and at the 3300 level, where NECESSARY PRECAUTIONS FOR MINING AT DEPTH In Room and Pillar Extraction: 1) Pillars must not be too small. 2) Pillar size must be uniform. 3) Extraction lines must be kept as straight and as uniform as possible. If they are irregular they should be brought back into line slowly. 4) Peninsulas of coal surrounded by gob must be avoided. 5) Pillars should not be disturbed after they have been formed. If it is necessary to increase the width of an opening, stripping or ribbing should be done gradually over a long distance. If increased width of openings is necessary at certain locations and can be anticipated, the openings should be widened during development. 6) Under no conditions should small pillars be left in the gob that would interfere with caving. In Long wall Operations: 1) Pillars formed during development for retreating longwalls should be uniform in size and shape. 2) Pillars should not be split after development, but if pillar splitting does become necessary it should not be carried out within the zone influenced by the working faces. 3) Width of levels should not be increased after the levels have been developed. If it does become necessary to widen a level it must be done gradually over a long distance by stripping or ribbing the coal ribs. 4) Extraction lines should remain uniform. If several walls are worked together—one behind the other—a uniform distance must be maintained between them and the wall faces must be kept as straight as possible. If the walls do get out of line, they must be brought back into line gradually to allow for a gradual change in the stress distribution over the area. 5) Stumps of coal, roof supports, etc. must not be allowed to remain in the gob to interfere with caving. 6) Midwalls should be built as rigidly as possible and properly maintained.

Jan 1, 1959