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By Jed H. Mosgrove, Paul M. Budzak

INTRODUCTION Good mine ventilation starts at the drawing board. A coal mine will either be adequately ventilated or not, depending upon how good a job was done in the planning. Poor planning will not only result in inadequate ventilation, but may also lead to low productivity. A mine foreman cannot achieve high productivity while trying to maintain 4.2 m3/s (9000 cfm) of air at his last open crosscut. PLANNING What will provide adequate ventilation? A rule of thumb in laying out a coal mine is to provide enough entries in the main entry system to keep air velocities at 2.5 m/s (500 fpm) or less; at this rate of flow, good ventilation may be expected. The intake and return air courses of a coal mine do not improve with age. Entries will deteriorate, ribs will slough, roof will fall, and clutter will accumulate. The resistance offered to air travel will continue to increase with each passing year. Providing enough airways for the present and the future cannot be emphasized too strongly. In order to better appreciate good planning and bring it into better focus, assume a hypothetical mine has the following features: entries 1.5 m (5 ft) high and 6.1 m (20 ft) wide; one intake and one return entry; the mine development is 4.8 km (3 miles) from the intake and upcast ventilation shafts; and the ventilation requirement is 141.6 m3/s (300,000 cfm). Air travel of 4.8 km (3 miles) into a mine and the same distance back to the fan is not unusual. However, to do so with one intake and one

Jan 1, 1981

By Hertha Freche

THE diffusion of magnesium and silicon from the core into the high-purity coating of Alclad sheet is important commercially, and led to the use of a duplex product for the study of diffusion by means of spectro-graphic analysis of successive layers. It has been found that in the duplex materials the diffusion of magne-sium from an undersaturated aluminum-magnesium alloy into its high-purity aluminum coating is approximately of the same order of magnitude as the diffusion of silicon from a saturated aluminum-silicon alloy into its high-purity aluminum coating. However, if magnesium and silicon are both present in the alloy in the ratio of Mg2Si they appear to diffuse in the approximate ratio of this compound. Finally, if the alloy contains silicon in excess of the amount required by magnesium silicide, the amount of diffused silicon in the high-purity aluminum coating will also be in excess. The interdiffusion of metals in the solid state is of both scientific and technical interest, because it is helpful in the study of the alloy structure and in the solution of problems pertaining to the strength and surface condition of the fabricated product. W. C. Roberts-Austen1 carried out the first quantitative determination of the coefficient of diffusion of gold into lead. This classical experiment was followed by a series of investigations on the diffusion of metals and nonmetals in iron and steel and in nonferrous metals and alloys. Recently the diffusion of copper in coated strong aluminum alloys was investigated by A. Burkhardt2. This appeared to be the first published investigation on the diffusion of metals into aluminum.

Jan 1, 1936

By E. H. Jr. Dix

OF all the alloying elements used in commercial aluminum alloys, copper stands out as by far the most important, and it is perhaps for this reason that the constitution of the aluminum-copper system has received the attention of a number of experimenters covering a period of approximately 20 years. It would be expected that during this time the equilibrium relations had been thoroughly and exactly worked out. In a general way this is true, but there is a surprising lack of agreement in the details of the high aluminum end of the diagram, particularly in regard to the solid solubility of copper in aluminum, which has been given variously as 2 per cent. to 5 per cent. at the eutectic temperature. The importance of this is much greater than might at first appear to one unfamiliar with modern commercial aluminum alloys. This is true because, with one exception, the susceptibility of the strong alloys to heat treatment depends, in part at least, upon the solid solubility relations of copper in aluminum. In 1919, Merica, Waltenberg, and Freeman1 published the first detailed information on these solubility relations. They found that the solubility of copper decreases with falling temperature from about 4 per cent. at 5.25° C. to about 1 per cent. at 300° C. and is apparently still diminishing at lower temperatures. In 1921 there was published a brief account of the results obtained in the National Physical Laboratory, Teddington, England.2 This laboratory, however, reported that 5 per cent. of copper is soluble in aluminum at 540° C., and that this amount decreases to about 3 per cent. at 20° C.

Jan 2, 1926

By Joseph F. Oesterele, Richard S. McCaffery

This investigation was undertaken to determine the quality of different iron blast-furnace slags as desulfurizing agents, and the possibility of using, in the blast furnace, materials of higher sulfur content than is now common. The solution of the problem would render possible the use of higher sulfur iron ores for pig iron and cokes containing more sulfur than now employed, and the economic manufacture of irons and steels of lower sulfur content. It is generally assumed that the sulfur that reaches the lower part of the iron blast furnace is removed from the pig iron by combining with lime to form calcium sulfide. Most of the sulfur introduced with the charge is in combination with iron or manganese or, perhaps in the coke, as a carbon compound.1 The iron and manganese sulfides are more soluble in the iron than is calcium sulfide, and as the latter is generally said to to be more soluble in the slag than the iron and manganese sulfides, this greater solubility of calcium sulfide in the slag tends to free the metal from sulfur. This greater solubility of the calcium sulfide is used not only to reduce the sulfur contents of the pig iron in the blast furnace, but by this means also low-sulfur steels are produced in the open-hearth and electric furnaces. The reaction2 FeS + CaO + CO = Fe + CaS + CO2 requires a high temperature and strongly reducing conditions in the presence of lime. The constitution of blast-furnace slags, first studied scientifically by Vogt13 indicated certain ranges of composition of the slag in which a

Jan 1, 1923

By Richard S. McCaffery, Joseph F. Oesterele

This investigation was undertaken to determine the quality of different iron blast-furnace slags as desulfurizing agents, and the possibility of using, in the blast furnace, materials of higher sulfur content than is now common. The solution of the problem would render possible the use of higher sulfur iron ores for pig iron and cokes containing more sulfur than now employed, and the economic manufacture of irons and steels of lower sulfur content. It is generally assumed that the sulfur that reaches the lower part of the iron blast furnace is removed from the pig iron by combining with lime to form calcium sulfide. Most of the sulfur introduced with the charge is in combination with iron or manganese or, perhaps in the coke, as a carbon compound.1 The iron and manganese sulfides are more soluble in the iron than is calcium sulfide, and as the latter is generally said to to be more soluble in the slag than the iron and manganese sulfides, this greater solubility of calcium sulfide in the slag tends to free the metal from sulfur. This greater solubility of the calcium sulfide is used not only to reduce the sulfur contents of the pig iron in the blast furnace, but by this means also low-sulfur steels are produced in the open-hearth and electric furnaces. The reaction2 FeS + CaO + CO = Fe + CaS + CO2 requires a high temperature and strongly reducing conditions in the presence of lime. The constitution of blast-furnace slags, first studied scientifically by Vogt13 indicated certain ranges of composition of the slag in which a

Jan 1, 1923

By Jed H. Mosgrove, Paul M. Budzak

INTRODUCTION Good mine ventilation starts at the drawing board. A coal mine will either be adequately ventilated or not, depending upon how good a job was done in the planning. Poor planning will not only result in inadequate ventilation, but may also lead to low productivity. A mine foreman cannot achieve high productivity while trying to maintain 4.2 m3/s (9000 cfm) of air at his last open crosscut. PLANNING What will provide adequate ventilation? A rule of thumb in laying out a coal mine is to provide enough entries in the main entry system to keep air velocities at 2.5 m/s (500 fpm) or less; at this rate of flow, good ventilation may be expected. The intake and return air courses of a coal mine do not improve with age. Entries will deteriorate, ribs will slough, roof will fall, and clutter will accumulate. The resistance offered to air travel will continue to increase with each passing year. Providing enough airways for the present and the future cannot be emphasized too strongly. In order to better appreciate good planning and bring it into better focus, assume a hypothetical mine has the following features: entries 1.5 m (5 ft) high and 6.1 m (20 ft) wide; one intake and one return entry; the mine development is 4.8 km (3 miles) from the intake and upcast ventilation shafts; and the ventilation requirement is 141.6 m3/s (300,000 cfm) . Air travel of 4.8 km (3 miles) into a mine and the same distance back to the fan is not unusual. However, to do so with one intake and one

Jan 1, 1981

By F. Julius Fohs

WITH portions of two coal basins within its borders and a few scattered fields already developed, the question arises: What is the future of Ken-tucky as an oil-producing State? Is the long list of failures due to lack of 'commercial pools, or unintelligent prospecting? A study of its beds and irregularities of structure points not only to a large waste of development money on unpromising areas, but also to the presence of a few structures well worthy of development. The surface rocks of Kentucky show in succession more than 4,000 ft. of Paleozoic sediments and more than 2,000 ft. of Cretaceous, Tertiary, and more recent deposits. Folding and erosion have brought these beds to the surface, where they have been observed and studied: in detail by my associate, James H. Gardner, myself, and others. This has given opportunity to observe the beds offering suitable reservoirs and having the proper impermeable covering; also the mapping of outcrops and outcrop lines, taken in conjunction with available well records, indicates that certain areas are worth testing, and with even greater definiteness shows areas which should be excluded, as devoid of possibilities. West of the Tennessee River, Cretaceous, Tertiary, and Quaternary sediments occur so that all trace of ancient folding is obliterated, the sediments overlapping unconformably Mississippian rocks. This area embraces 2,000 square miles, or one-twentieth of the area of the State, the Paleozoic rocks covering the remainder. Since there is nothing upon which to base the location of tests for oil and gas in the Cretaceous-Tertiary beds of Kentucky, the Paleozoic area will be chiefly considered.

Jan 3, 1915

By R. J. Armstrong, J. J. McKay

The Montana Phosphate Products Co. is currently operating three underground phosphate mines in Powell County, MOnt. † In this area the Phosphoria formation is from 35 to 50 ft thick and contains a bed of phosphate rock varying in thickness from 2 1/2 to 5 ft, overlain by 12 to 30 ft of cherty quartzite, and underlain by about the same thickness of quartzite and shaly to cherty beds. In general, the phosphate bed has a reasonably hard quartzite footwall, as well as a hard cherty hanging wall, both of which greatly facilitate the mining operation. Folding has deformed the phosphate bed to a considerable degree in the area. It is carried to surface by several of the anticlines and lowered to considerable depths in some of the syn-clines. The main structural features affecting the mining operations of the company are the Garrison anticline and the adjoining syncline and succeeding limb of a second anticline on the east (Fig I). The axis of the folding strikes roughly northwest-southeast. The three mines, namely, the Anderson, Graveley, and Luke are on different limbs of the above folds. Accordingly, the dip of the bed, and consequently the mining method, in each mine differs to a considerable degree from that of the others. For this reason, each operation will be dealt with separately. Anderson Mine LOCATION AND DEVELOPMENT Topographically this mine is in a narrow valley, the bottom of which has an altitude of 5200 ft. The phosphate bed outcrops near the ridge on the east and dips towards the valley floor at an angle of from 25 to 30°,

Jan 1, 1950

By F. T. Lee

Directional dependence of strength and deformation properties of the Mount Waldo granite pluton in southeastern Maine is controlled by joints and microfractures whose orientations are linked to flow- induced alignment of microcline crystals. Longitudinal and cross joints which formed during cooling of the mass, as well as much younger sheeting fractures, are commonly associated with subparallel, discontinuous microfractures. The orthogonality of microfractures (open, closed; filled, unfilled; bubble planes) establishes the ease of splitting of the granite. The easiest splitting direction (rift) is subhorizontal, the second easiest direction (grain) is parallel to the cross joints, while the direction of least easy splitting (hardway) is parallel to the longitudinal joints. Static and dynamic measurements made in the field and laboratory established that structural features are responsible for the marked stiffness anisotropy of the granite. In the central part of the pluton the static Young's modulus in the north-south direction averages 31.1 GPa, and 20.9 GPa in the east-west direction; the stiffer direction being parallel to the long C-axes of microcline phenocrysts and microfractures as identified in outcrop, core samples, and thin sections. Vertical downhole sonic measurements of dynamic moduli ranging from 2.5 to 16.2 GPa appeared to be anomalously low when compared to the static horizontal values. However, the field sonic values were confirmed by laboratory sonic pulse testing of oriented cores. The field results reflected closely spaced layers of open horizontal microfractures. Those deformation and strength properties that are closely tied to bubble planes, filled microfractures, and microcline orientation could be extrapolated to greater depths with good hope of success.

Jan 1, 1984

By A. G. H. Anderson, Eric R. Jette

A few years ago, while the writers worked on the constitution of ternary and quaternary alloys consisting mainly of iron, chromium and siliconl,2 some information on microstructures and hardness, not incorporated in the published work, alas obtained. It has not been possible to do any further work on the properties of the alloys. The information possessed is hereby presented for the interest it may have in connection with the constitution of the alloys. Microstructures Referring to the iron-chromium-silicon diagram,' the regions that received most attention were those in which the sigma phase appears. It was found that the mode of occurrence of this phase varied much with the condition under which it mas formed, and the mode influenced considerably the hardness of the alloys. In some slowly cooled alloys, well within the alpha + sigma-phase boundary, sigma occurs in pabterns suggesting a eutectic. The structure of such an alloy is shorn in Fig. 1, showing it to be partly coarsely laminated and partly globular mottled. In other annealed and slowly cooled alloys, the lanlinated structure is entirely absent, and sigma appears in an irregular distribution of sharply cornered elongated areas (Figs. 2 and 3). These areas all possess a more or less mottled structure. A carbide phase is also visible in these two photomicrographs; it is represented by bright white arras of various shapes, sometimes apparently enveloping the sigma. Quenched and aged specimens, whose compositions arc: located near the phase boundary between alpha and sigma + alpha regions, have structures not unlike martensite (Figs. 5 and 6). Fig. 4 shows the structurc of alloy No. 35 as quenched from 1100" C.; it is a typical solid solu-

Jan 1, 1938

By Eric R. Jette, A. G. H. Anderson

A few years ago, while the writers worked on the constitution of ternary and quaternary alloys consisting mainly of iron, chromium and siliconl,2 some information on microstructures and hardness, not incorporated in the published work, alas obtained. It has not been possible to do any further work on the properties of the alloys. The information possessed is hereby presented for the interest it may have in connection with the constitution of the alloys. Microstructures Referring to the iron-chromium-silicon diagram,' the regions that received most attention were those in which the sigma phase appears. It was found that the mode of occurrence of this phase varied much with the condition under which it mas formed, and the mode influenced considerably the hardness of the alloys. In some slowly cooled alloys, well within the alpha + sigma-phase boundary, sigma occurs in pabterns suggesting a eutectic. The structure of such an alloy is shorn in Fig. 1, showing it to be partly coarsely laminated and partly globular mottled. In other annealed and slowly cooled alloys, the lanlinated structure is entirely absent, and sigma appears in an irregular distribution of sharply cornered elongated areas (Figs. 2 and 3). These areas all possess a more or less mottled structure. A carbide phase is also visible in these two photomicrographs; it is represented by bright white arras of various shapes, sometimes apparently enveloping the sigma. Quenched and aged specimens, whose compositions arc: located near the phase boundary between alpha and sigma + alpha regions, have structures not unlike martensite (Figs. 5 and 6). Fig. 4 shows the structurc of alloy No. 35 as quenched from 1100" C.; it is a typical solid solu-

Jan 1, 1938

By Fred W. Stiefel

To open the Fisher Hill mine of the Republic Steel Corporation, it was necessary to sink an inclined shaft into the rock and excavate stations, drifts, and ore pockets. This inclined shaft, or slope, q ft. 8 in. high by 28 ft. 2 in. wide, has compartments for two 5-ft. gauge ore-skip tracks of 120-lb. rail, one 5-ft. gauge man-skip track of 60-lb. rail, a concrete stairway, and service pipes consisting of a 12-in. compressed-air line, an 8-in. pump-discharge line, and a 4-in. water-supply line. When we were requested to investigate the work, the progress being made (by another organization) amounted to only 2 ½ ft. advance in 24 hr. We reported that progress of at least 6 ft. per day could be made. As a result, the Defense Plant Corporation, through the Republic Steel [ ] Corporation, entered into a contract with us to sink the shaft. The contract contained a penalty and bonus clause predicated upon an advance of 150 ft. per month. The average advance was 7.8 ft. per day; that in the best six-day week was 60 ft. and that in the best month, 215.5 ft. in 25 working days. The drilling was performed by 3 ½ -in. wet drifter drills mounted on five 8-ft. columns (see accompanying illustration). Even though a full-face drilling and mucking operation is customarily desirable, the steep slope, with the accumulation of water and fine debris at the face, made a modified heading and bench operation preferable. The heading and bench were of equal height. The five columns, instead

Jan 1, 1945

Graham Macfarlane, Louisville, Ky. (communication to the Secretary*):—In the paper by S. Whinery under the above caption mention is made of the occurrence of Clinton iron-ore in Kentucky and Tennessee. I believe that this is really a ferruginous limestone in what the Tennessee Geological Survey calls the Fernvale formation. In Davidson and Sumner counties, Tennessee, this occurs at about the horizon stated by Mr. Whinery. The maximum thickness of the deposit is from 10 to 12 ft., but it averages between 6 and 8 ft., lying practically horizontal. The Red River Furnace Co., under my direction, opened a mine in the Fernvale " red rock" near Goodlettsville, Tenn., several years ago. When it was first found we assumed it to be Clinton ore, but the absence of the characteristic Clinton fossiliferous structure and other evidence satisfied us that it is really limestone saturated with iron oxide. I think the very low ratio of SiO2 and Al2o3 to iron content as compared with the usual ratio in the Clinton ore is also evidence in favor of its being the Fernvale. The Tennessee Geological Survey states that at outcrops where this ore has been leached it carries about 44 per cent. of iron; under cover, from 20 to 25 per cent. of iron and from 3 to 6 per cent. of silica, the remainder being chiefly calcium carbonate. Its phosphorus content is irregular and generally rather high for a foundry-iron mixture. Since it is more than self-fluxing, we have at times operated with a mixture of brown hematite and red ore with no limestone.

Jan 1, 1913

By F. Louis Grammer

The difference between blast-furnace gas and ordinary producer-gas is chiefly that blast-furnace ga,s is higher in CO2 and lower in hydrocprbons and hydrogen, as is shown in Table I. Table I.— Volume-Composition of Producer-Gas and Blast-Furnace Gas. Producer-Gas. Blast-Furnace Gas. Per Cent. Per Cent. (Volume.) (Volume.) CO......22 to 33 25.5 CO2........ 6 to 3 13.0 H...13 to 7 1.5 CH4........ 3 to 1.5 0.0 N..54 to 60 60.0 If natural gas, water-gas, or by-product coke-oven gas be available, blast-furnace gas can be made to resemble very closely in calorific value the average producer-gas by merely mixing in one of these products, which are richer in hydrocarbons and hydrogen. Blast-furnace gas, however, possesses a virtue which is sometimes absent in producer-gas, especially with coals very high in sulphur—namely, that blast-furnace gas is relatively free from sulphur. In some regions the sulphur in coal is an acute problem, and it is highly desirable to find uses for the mine-products which are specially high in sulphur-content. An advantage would be gained if the coal were coked before charging into the gas-producers, but this adds to the expense. Sulphur may be partly eliminated from coal by washing it, the success depending upon the form in which the sulphur occurs, and upon the efficiency of the washer, but it cannot always be removed to the extent desired at most American plants. It is not practicable to remove all the sulphur from producer-gas by washing it, though Mr. Reinhardt, of Germany,

Jan 1, 1909

R. B. BRINSMADE, Puebla, Puebla, Mexico (communication to the Secretary*) :-As I have previously considered the general equations for mine-valuation,1 I will here discuss only that part of Mr. Finlay's paper criticized by E. E. White, along with some of the general principles of mining taxation, under the following six topics: 1. Rate of interest earned by sinking-fund. 2. Rate of interest earned by investment. 3. Place of royalty item in valuation. 4. Place of taxation item in valuation. 5. Calculation of future ore-prices. 6. Valuation of undeveloped mining land. 1. Rate of Interest Earned by Sinking-Fund.-Mr. Denny's quoted opinion of a 3 per cent. rate is evidently based on English conditions before the Boer war. The great destruction of liquid capital by the great wars and catastrophes since 1897, along with the flood of gold and consequent rise in the average index of commodity prices, has undoubtedly increased the rate of interest at least one-half per cent. In the United States sound savings banks now allow 4 per cent. on deposits, while safe bonds are quoted at prices which yield even 5 per cent.. 2. Rate of interest Earned by Investment.-Gold-mines with uncertain and scanty ore reserves, the objects of Mr. Denny's quoted remarks, are quite different from iron,. copper, or coal mines with definite mineral reserves blocked out ahead by drilling or driving. While 10 per cent is often all inadequate yield from gold-mines, the latter class of mines are often, as safe as city real estate and resemble it as an investment in more ways than one.

Jan 10, 1913

By Oswald J. Heinrich

The deposit of rock salt along the shores of Lake Huron, in Canada, has been brought before the public during the last six months, in consequence of the developments made by the diamond drill at Goderich. It is likely to be of more than common interest in the future, since now actual operations have been commenced to exploit the deposit and work it by regular mining. The methods of mining rock salt being but little known in this country, it may be of interest to make a few general remarks in regard to them before entering, upon the description of this new mining enterprise. According to the conditions under which salt is .found in nature, various methods have been resorted to, in course of time, to make it available for the human race. They consist in: A. Natural or solar evaporation. B. Artificial evaporation, either exclusively or in connection with the former. C. Mining the rock salt in its natural state, and converting it to a marketable product, if need be, by simply pulverizing it. Without going into the details of the various methods of making salt available in an economical point of view, dependent on its degree of pority, or on various local influences, we cannot refrain from alluding to the general principles which influence the mining and manufacturing of salt in countries where they have been carried on for hundreds of years. ECONOMICAL CONDITIONS FOR SUCCESS. Salt being one of the articles of prime necessity, and one universally distributed throughout nature, it must always be sold at a comparatively low price. It would even be quoted in the market at prices far below those now ruling, if it were not for the high duties generally imposed upon it, for purposes of state revenues. But looking closer into the subject, it will be found that this duty is probably one of the least oppressive, although in some countries it exceeds sixfold the cost of profitable production. To produce the article at the lowest possible cost requires, therefore, a

Jan 1, 1879

By W. E. Coxe

In 1857 the Philadelphia and Reading Railroad Company, whose main line extended from Philadelphia to Pottsville, Pennsylvania, with branches into the coal regions of Schuylliill County, made a contract with the Fairmount Rolling Mill, at Philadelphia, for the rerolling of some four thousand tons of iron rails. The essential features of the agreement were that the old rails should be piled with puddled iron and rolled into flats for the rail pile, which latter was • to be of a section seven inches square, and after being heated, and reduced, by rolling, to a bloom of a section about fire inches by six inches, was to be reheated, before being finished into the rail of the T pattern, four inches high, weighing sixty-four pounds per yard. Great care was exercised in the execution of this contract, and the rails being distributed over all parts of the road, gave general satisfaction by their excellent wear. Five years afterward, the principal proprietor and manager of the Fairmount Rolling Mill was elected President of the Reading Railroad, and very many of the rails made under his supervision were still in use in the tracks of the company, of which he had just assumed the management. His first efforts were, therefore, directed to the procuring of more rails of the same quality wherewith to replace those worn out. Here he encountered some trouble, makers refusing to bid because of the details in the specification, the required reheating being the objectionable feature, for which it was generally intimated they would not be sufficiently remunerated for the increased labor, extra coal consumed, and the changes necessary from the established methods of working. Most of the new rails were, therefore, bought, and the old rails rerolled without regard to any particulars as to the manner of piling, heating, etc., each manufacturer furnishing what he deemed the best article possible for the money. As a consequence, rails of all imaginable grades were placed in the tracks, some giving out in six

By W. E. C. Coxe

IN 1857 the Philadelphia and Reading Railroad Company, whose main line extended from Philadelphia to Pottsville, Pennsylvania, with branches into the coal regions of Schuylkill County, made a contract with the Fairmount Rolling Mill, at Philadelphia, for the rerolling of some four thousand tons of iron rails. The essential features of the agreement were that the old rails should be piled with puddled iron and rolled into flats for the rail pile, which latter was to be of a section seven inches square, and after being heated, and reduced, by rolling, to a bloom of a section about five inches by six inches, was to be reheated, before being finished into the rail of the T pattern, four inches high, weighing sixty-four pounds per yard. Great care was exercised in the execution of this contract, and the rails being distributed over all parts of the road, gave general satis¬faction by their excellent wear. Five years afterward, the principal proprietor and manager of the Fairmount Rolling Mill was elected President of the Reading Railroad, and very many of the rails made under his supervision were still in use in the tracks of the company, of which he had just assumed the management. His first efforts were, therefore, directed to the procuring of more rails of the same quality wherewith to replace those worn out. Here he encountered some trouble, makers refusing to bid because of the details in the specification, the required reheating being the objectionable feature, for which it was generally intimated they would not be sufficiently remunerated for the increased labor, extra coal consumed, and the changes necessary from the established methods of working. Most of the new rails were, therefore, bought, and the old rails rerolled without regard to any particulars as to the manner of piling, heating, etc., each manufacturer furnishing what he deemed the best article possible for the money. As a consequence, rails of all imaginable grades were placed in the tracks, some giving out in six

Jan 1, 1877

By John M. Crowl, L. E. Sawyer

5.3-1. General Public Resistance to Strip Mining. Surface (strip) mining is the oldest recorded method of extracting coal and other minerals from the earth. This method of mining completely alters the topography of the earth's surface, leaving an area of more or less parallel ridges or of peaked mounds of the materials which overlay the mineral seam. It destroys all original vegetation and provides materials for new type soil. During the early years the acreage mined by this method was small, land was plentiful, and with a growing young nation no thought was given to the restoration of the disturbed areas to some form of productive use. Early in the present century the development of steam shovels and drag-lines made it possible to remove thicker overburden to recover the products. With the deeper digging, the size of the disturbed areas increased. With this increase in the size of equipment and the improvement of blasting techniques, mining was expanded into more prominent locations and to areas of more valuable land. The more progressive operators became aware of the need to reclaim those areas for some productive use. Electric shovels with capacities of up to 200 cu yd and draglines with capacities of 145 cu yd, capable of uncovering products over 100 ft below the surface, are now in use. Combined with the increase in the size of equipment, the expansion of contour mining or rim stripping in the mountainous areas has focused public attention on the need for a sound reclamation program for all disturbed areas. APPEARANCE. After mining, the areas consist of varying percentages of rock, shale, slate, and soil material devoid of all plant and animal life. Unless a definite reclamation plan is carried out, many of the mined areas will remain bare for a period of years. The topography of the area is completely altered. What may have been level to rolling land in cultivation, in grass, or in timber is thrown up into a series of ridges or mounds.

Jan 1, 1968

By E. P. Polushkin

The object of this paper as to show that the structural composition of an alloy may be found by the planimetric measurement of the total area occupied by each of the constituents on a few representative photomicrographs of this alloy. When the area is determined the volume and the proportional weight of the constituent may be calculated. This method has been used for the determination of the structural composition of binary eutectics and other binary alloys with known constituents; also the composition of unknown constituents in binary alloys. The accuracy of the method is. high enough to justify its application to metallographic problems instead of the chemical analysis. THIS work has for its purpose the establishment of a new method for determining the structural composition of alloys. The area occupied by a constituent on a few representative photomicrographs of the alloy is measured, by a planimeter, especially designed for metallographic work, and the volume and proportional weight of the constituent calculated. Experiments have shown that 'the results are accurate enough to justify the application of the method to many problems in metallographic research instead of chemical analysis. The advantage of the method is the possibility, of determining the amount of the constituents with-out separating them from the alloy; their composition may also be determined if the ultimate chemical analysis of the alloy is known. DESCRIPTION OF PLANIMETER Suppose Fig. 1 represents a part of a photomicro-graph on which the total area of the black figures is FIG. 1?-PART OF PHOTOMICROGRAPH ON WHICH TOTAL AREA OF BLACK FIG- URES IS TO BE FOUND. to be found. By a system of parallel lines drawn short equal distances apart all figures may be divided into trapezoids. As the area of a trapezoid is equal to its median multiplied by its altitude, the relation between the total areas of the black and the white figures comprised within each strip is equal to the relation between the sums of medians for these figures respectively.

Jan 12, 1924