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By C. G. Dunn, J. L. Walter

Secondary recrystallization to the (110) [001] texture in high-purity silicon iron occurs if low-oxygen material is annealed in a nonoxidizing atmosphere. Any departure from these conditions results in a growth of (100) oriented grains. The nature of the matrix and secondary recrystallization structures and textures and the nature of grain boundary interactions during growth show that the low gas-metal interfacial energy of the (110) surfaces provides the driving force for growth of these grains. A type of grain growth, characterized by a driving force which derives from energy differences of {hkl} surfaces at the gas-metal interface, has been treated in recent papers.&apos;-7 Secondary recrystallization to the cube text!:: in high-purity silicon iron provides one example. The present paper also deals with a surface energy driving force but the texture that results by secondary recrystallization is not the cube texture; it is a texture in which the (110) plane is in the plane of rolling and the [001] direction is in the direction of rolling. The phenomenon described in this paper is different from the impurity (dispersed phase)-controlled secondary recrystallization process in which the (110) [001] oriented grains grow under the action of grain boundary driving forces.8-12 It is also different from tertiary recrystallization,2 which also produces the (110) [001] texture in high-purity silicon iron, since the matrix textures and grain sizes are different. Finally, it is unlike any other form of secondary recrystallization reported in the literature. The possibility of obtaining the (110) [001] texture in high-purity silicon iron became clear in a study of the effect of impurity atoms on the energy relationships of (100) and (110) surfaces. In this study Walter and Dunn6 observed the migration of (100)/(110) boundaries, i.e., boundaries between two grains, one of which has a (100) plane and the other a (110) plane, respectively, parallel to the plane of the sheet specimen. At 1200°C the (100)/(110) boundaries advanced into (100) grains in a vacuum anneal, then reversed their direction and migrated into (110) grains in a subsequent anneal in impure argon. Finally, the direction of migration reversed once again with (110) grains growing into (100) grains in a second vacuum anneal. These results were explained in terms of a change in concentration of oxygen atoms at the gas-metal interface during the anneals. Thus, oxygen atoms were added to the surface during the anneals in impure argon to the point where ?100, the specific surface energy of the (100) oriented grains, was lower than ?110, the surface energy of (110) oriented grains. In vacuum, however, the oxygen concentration at the surface was lowered to the point where ?110 < ?100. Concerning the possibility of secondary recrystallization in high-purity silicon iron with a low initial oxygen concentration, the observed effect of adsorbed oxygen atoms has indicated6 that a good vacuum anneal would favor the rapid growth of matrix grains with the (110) plane in the plane of the sheet much more than grains in the (100) orientation. The growth of only (110) oriented grains of course would depend upon y110 being less than ?hkl, where hkl refers to any plane different from (110). The present paper is concerned with the application of the above ideas to secondary recrystallization to the (110) [001] texture in high-purity silicon iron. The matrix and secondary recrystallization textures and structures are defined and discussed. Observations of growth of nuclei for secondary recrystallization and of boundary interactions are included to provide direct information on the surface energy relationships between (110) and other (hkl) surfaces. EXPERIMENTAL PROCEDURE As before, 2,4-6 high-purity iron and silicon were melted and cast in vacuum to provide an alloy containing 3 pct Si with less than 0.005 wt pct impurities. The oxygen content of the ingot was lower than in previous ingots, being approximately 3 ppm (by weight). The carbon content of this ingot may have been slightly higher than was found for previous ingots. The same rolling and annealing schedule used previously2 was followed in this study to obtain samples 0.012 in. (0.3 mm) thick. These samples were electropolished prior to annealing. After rolling and polishing, the oxygen content of the material was approximately 6 ppm; material used in the previous studies contained about twice this amount of oxygen.

Jan 1, 1961

By Shosei Serata

Serious floor heave of up to 2.4 m in a 2.4-m high mine entry was eliminated by applying the stress control method of mining, as a last resort, at the No. 5 coal mine of Jim Walter Resources, Inc., in the Black Warrior coal basin near Birmingham, Alabama. Underground observation of the first 3-room entry created using the stress control method is discussed here. The behavior of the test entry, which eliminated the heave problem, is analyzed in relation to similar studies conducted in a salt mine under similar ground conditions by utilizing finite element analysis.

Jan 1, 1984

By Fred C. Bond, Jen-Tung Wang

Comminution energy is principally energy of deformation before breakage, which appears as heat An empirical equation is presented which covers the entire comminution range. The new strain-energy theory considers comminution from the known principles of mechanics and the reduction ratio. Energy requirements according to the different theories the romnnred. THE present status of the theory of comminution is extremely unsatisfactory. The amount of various ores and rock products crushed and ground annually approaches the staggering sum of perhaps one half billion tons. Yet the basic concepts underlying an operation of such magnitude are unknown, and actual knowledge of what takes place in comminution is almost entirely empirical. The responsibility for this situation cannot be charged to apathy or lack of appreciation of the importance of the problem. Many attempts have been made to evolve a workable hypothesis, but none has been completely successful. General Considerations In order to break rock, it must be subjected to a stress which strains the rock beyond its critical breaking point. The stress imparts energy to the rock, most of which is released in the form of heat when the stress and resulting strain are removed. If the strain induced exceeds the critical strain, the energy is released by breaking; if the induced strain does not reach the critical point, the energy is released with removal of the stress as energy of resilience. Rock is a brittle material and it is assumed that it breaks approximately at its yield point, so that no permanent deformation results from strains below the critical. When rock is broken the total energy input is accounted for by the heat liberated, and by the surface energy of the new surface produced. A small and probably negligible amount is released as noise. Rock is commonly broken under compression and the applied stress is ordinarily compressive. However, for breakage to occur, it is only necessary that the induced strain exceed the critical value, and this strain may represent the resultant of compressive, shearing, and tensile forces. The stress-strain diagram of rocks under compression, and the modulus of elasticity as determined therefrom, should be fundamental considerations in the development of any theories of rock breakage. Crushing in jaw or gyratory crushers results primarily from a squeezing action, and reduction in a hammer mill is the result of impact. The action in rod and ball mills is a combination of impacting, squeezing, and wearing away by attrition, or rubbing. In ordinary crushing and grinding, the forces are applied at protruding points and are not distributed evenly throughout the rock. This is one of the features of comminution which theoretical considerations have not covered adequately. Another feature is the effect of impact velocities, which may greatly influence the total energy required for breakage. Impact velocities may vary from 1 or 2 fps in crushers to 10 or 20 fps for ball mills, and as high as 100 or more for hammer mills. However, according to the findings of geophysicists, the velocity of sound and of compression waves in stone is many times greater; the primary longitudinal compression waves travel at perhaps 15,000 fps, and the secondary transverse waves, which may reach the surface and cause cracks to form thereon, travel at perhaps 5000 fps. When a crack tip forms, the total surrounding stresses are concentrated in this tip, which rapidly extends throughout the rock particle.1 It would seem that the energy required to deform the rock beyond its critical strain, resulting in the formation of a crack tip, represents practically all of the energy required. Most of the primary crack tips presumably form on the surface. A simple method of designating feed and product size is necessary for the evaluation of crushing and grinding results. Taggart&apos;s suggestion2 that the 80 pet passing size be used has been found very practical. In this paper, the square opening screen size which 80 pct of the feed passes is designated as the feed size F, and the size which 80 pct of the product passes, or the product size, is designated as P. The reduction ratio at the 80 pet passing size, or F/P is designated as n. The feed and prod-

Jan 1, 1951

By Fred C. Bond, Jen-Tung Wang

Comminution energy is principally energy of deformation before breakage, which appears as heat An empirical equation is presented which covers the entire comminution range. The new strain-energy theory considers comminution from the known principles of mechanics and the reduction ratio. Energy requirements according to the different theories the romnnred. THE present status of the theory of comminution is extremely unsatisfactory. The amount of various ores and rock products crushed and ground annually approaches the staggering sum of perhaps one half billion tons. Yet the basic concepts underlying an operation of such magnitude are unknown, and actual knowledge of what takes place in comminution is almost entirely empirical. The responsibility for this situation cannot be charged to apathy or lack of appreciation of the importance of the problem. Many attempts have been made to evolve a workable hypothesis, but none has been completely successful. General Considerations In order to break rock, it must be subjected to a stress which strains the rock beyond its critical breaking point. The stress imparts energy to the rock, most of which is released in the form of heat when the stress and resulting strain are removed. If the strain induced exceeds the critical strain, the energy is released by breaking; if the induced strain does not reach the critical point, the energy is released with removal of the stress as energy of resilience. Rock is a brittle material and it is assumed that it breaks approximately at its yield point, so that no permanent deformation results from strains below the critical. When rock is broken the total energy input is accounted for by the heat liberated, and by the surface energy of the new surface produced. A small and probably negligible amount is released as noise. Rock is commonly broken under compression and the applied stress is ordinarily compressive. However, for breakage to occur, it is only necessary that the induced strain exceed the critical value, and this strain may represent the resultant of compressive, shearing, and tensile forces. The stress-strain diagram of rocks under compression, and the modulus of elasticity as determined therefrom, should be fundamental considerations in the development of any theories of rock breakage. Crushing in jaw or gyratory crushers results primarily from a squeezing action, and reduction in a hammer mill is the result of impact. The action in rod and ball mills is a combination of impacting, squeezing, and wearing away by attrition, or rubbing. In ordinary crushing and grinding, the forces are applied at protruding points and are not distributed evenly throughout the rock. This is one of the features of comminution which theoretical considerations have not covered adequately. Another feature is the effect of impact velocities, which may greatly influence the total energy required for breakage. Impact velocities may vary from 1 or 2 fps in crushers to 10 or 20 fps for ball mills, and as high as 100 or more for hammer mills. However, according to the findings of geophysicists, the velocity of sound and of compression waves in stone is many times greater; the primary longitudinal compression waves travel at perhaps 15,000 fps, and the secondary transverse waves, which may reach the surface and cause cracks to form thereon, travel at perhaps 5000 fps. When a crack tip forms, the total surrounding stresses are concentrated in this tip, which rapidly extends throughout the rock particle.1 It would seem that the energy required to deform the rock beyond its critical strain, resulting in the formation of a crack tip, represents practically all of the energy required. Most of the primary crack tips presumably form on the surface. A simple method of designating feed and product size is necessary for the evaluation of crushing and grinding results. Taggart&apos;s suggestion2 that the 80 pet passing size be used has been found very practical. In this paper, the square opening screen size which 80 pct of the feed passes is designated as the feed size F, and the size which 80 pct of the product passes, or the product size, is designated as P. The reduction ratio at the 80 pet passing size, or F/P is designated as n. The feed and prod-

Jan 1, 1951

By M. H. Merriss

In the last few years, there have been developed at the plant of the Nichols Copper Co., Laurel Hill, &apos;Borough of Queens, New York City, improvements in electrolytic copper refining by the series system that have materially increased the flexibility and economy of that system. The purpose of this paper is to discuss, as of interest to refiners and to those who have copper to refine, as well as to the engineering profession in general, the changes&apos; that have taken place resulting in wider application and increased efficiency of the series system. Copper is electrolytically refined in two ways, which are spoken of as the "multiple system" and the "series system." In both systems, the electrolytic tanks are in series electrically. In the multiple system the electrodes in a single tank are in multiple or in parallel, thus: There are two important adaptations of the series process, one represented by the series electrolytic tank room at the Baltimore Copper, Smelting & Rolling Co., Baltimore, Md., and the other by that of the Nichols Copper Co.&apos;s plant. At Baltimore, the anode is rolled to perfect

Jan 1, 1926

By E. G. Banks

This paper is presented in the belief that metallurgists and chemists will be interested in the practice of grinding in tube-mills in connection with stamps, especially since the records of working here given extend over a lengthy period of time (since May, 1905). The ore from the Waihi mine—more especially that produced in the upper levels—contains a large proportion of hard, chalce-donic quartz, and the gold exists in an exceedingly fine state, conditions which necessitate very fine crushing in order to obtain a high extraction of the precious metal. Before the introduction of tube-mills at the 90-stamp Waihi mill, it was found necessary to stamp through 40-mesh (1,600 holes per sq. in.) woven wire-screens, having a fairly high discharge. The pulp then graded : Per Cent. Per Cent. On 50-mes11, .- 0.1 On l20-mesh ..8.77 On 60-mesh, . 8-74 On 150-mesh,.... 7.48 On 80-mesh,... 16.06 Passed 150-mesh,... 55.19 On 100-mesh,.... 3.66 The stamp-dnty was 2.89 short tons per stamp per day, or a total of 260 tons daily. Although the extraction on this pulp was: gold, from 88 to 90 per cent., and silver, from 74 to 78 per cent., it was recognized that finer grinding of the sands would prove beneficial, provided a machine could be found to do this work economically. Various grinding-mills and pans were tried, but without satisfactory results, the particles of sand being so hard that the capacity of any of the machines was too small to be economical. The results of grinding in tube-mills in other countries were so satisfactory that three tube-mills mere erected at the Waihi

Jan 1, 1908

By Arthur F. Taggart

ENGINEERING education today is like a crazy quilt of somber wools and gaudy shoddy, chain-stitched on an academic assembly line, and sold at ever mounting prices to inexperienced youths for lifetime use. Each engineering school offers a half-dozen or so patterns with essentially the same skimpy wool content. Sales appeal is in the color of the shoddy, denoted by the hopeful adjectives chemical, civil and the like. This article is argument for an all wool product made by slow, careful handwork. Bluntly it proposes a thorough four-year undergraduate drill in fundamental science and general engineering empirics, leavened by continuing study of the third of the engineer&apos;s troubles: Man. It is not contended that existing methods of engineering education have failed to start men on the path to successful engineering practice (too many of you have started that way); rather, social conditions and the bounds of knowledge have changed tremendously, and corresponding alterations in the pattern of engineering education are overdue. We&apos;ll Teach the Specifics The first part of this contention is illustrated by excerpts from a letter received recently from an officer of one of the largest corporations: "We are interested in employing two or three outstanding young engineers to be placed on a special training program to develop them as design and construction engineers.... "We propose to put these men on a four-month indoctrination and orientation course after which they would be given job-training assignments for a period that will vary from about six months to about a year and a half depending upon the aptitudes, abilities and intelligence of the candidates.... "I am not too fussy about what kind of engineers the men might be insofar as academic courses are concerned. They could be.. . in almost any engineering classification.... We can furnish the additional training beyond the academic fundamentals. "The starting rate for these jobs would be $326 per month...." This letter is not unique; rather it is representative of a practice that has become common. It is industry&apos;s enforced response to the general refusal by young graduates to submit to union domination in order to gain operating experience at the labor level. The message to engineering schoolteachers is plain: You teach the fundamentals; we&apos;ll teach our practice and pay the graduate to learn it. The letter means to the student that time spent in school studying the specific practices of particular industries is waste compounded. The school can&apos;t give the equivalent of what industry teaches, wherefore industry will still demand apprenticeship. The student must pay for the specific instruction at school instead of being paid to take it later. And time-consuming specifics crowd out drill in basic scientific and technical subjects as well as liberal arts.

Jan 1, 1952

By E. J. Roberts

Prior to 1916, thickening was an art, and any accurate decision as to what size of machine to install to handle a given tonnage of a specific ore must have been one of those intuitive conclusions, based on both intimate and extensive acquaintance with thick-ners and ore pulps. Then in 1916 "knowledge of acquaintance," became "knowledge about" with the publication of the Coe and Clevenger paper.&apos; The unit operation of thickening had graduated to the status of an engineering science. The fundamental similitude relationships for the two major phases of the operation were defined so clearly that batch tests on models as small as liter cylinders could serve to specify protypes as large as 325 ft in diameter. It is quite apparent from reading the literature that Coe and Clevenger&apos;s contribution is not generally appreciated. In so far as the basic engineering relationships are concerned, the only real advance which has occurred in the 30 odd years which have elapsed since the Coe and Clevenger paper is the recognition of the effect of the rakes on the thickening process. Bull and Darby2 noted this in 1926, and the extensive use of the "gluten type" thickener, in which the effect is magni-fied, bears witness to its importance. Comings3 further verified this effect of the rakes. As a matter of fact, a number of papers show an apparent regression from the Coe paper in that the area determinations are made on the basis of a single test from One concentration of solids. Coe and Clevenger amply demonstrated that this is unsafe, since the controlling zone may be one other than that of the feed dilution. Comings3 neatly demonstrated this without apparently realizing it. Of course there have been significant advances in the application of the operation to industry. Open tray thickeners were introduced to save area; balanced tray thickeners, washing thickeners, and multifeed clarifiers were developed with all of their special hydraulic and mechanical problems. Combinations of all kinds have been introduced, such as combination agitators and thickeners, combination flocculators and clarifiers, combination thickeners and filters. With the establishment of the operation on a firm engineering foundation, installation was facilitated and expansion proceeded. There are still problems, of course, functional as well as mechanical. Sometimes the moisture in the underflow obtained in practice is not as low as is expected on the basis of the test data. Sometimes the underflow is so "thick " that its discharge and subsequent handling requires special attention. Island formation plagues some operators. The use of the thickener as a surge basin and blending tank in the cement industry poses unusual problems. Design of rakes and the drive mechanism must be continually im-proved. Corrosion problems must he overcome. Power requirements for raking the settled solids occasionally is the controlling factor as it was in the case of the all American Canal desilting installation. Other similitude relationships and design problems come into the picture when we enter the field of clarification or nonline settlement. We have an energy dissipation problem in introducing the feed and any models must satisfy the Froude model relationships. Autoflocculation requires detention which involves the same similitude laws that we encounter in the compression zone. Approach to an Exact Science The next step beyond having control of the similitude relationships is to understand the why of these relationships right back up the line to first principles. The ultimate might be that, if given the mineralogical composition of the solids and their size distribution together with an analysis of the suspending liquid, we could calculate the entire thickening behavior of the system. Then we could say we had reduced the operation to an exact science. True it might be more trouble getting this basic analytical data than to make our empirical determinations for area and volume, and we would need an ENIAC to calculate the results, but that does not detract from the desirability of such understanding. Considerable work has been done by the chemical engineers with this end in view. Comings,3 Egolf,4 Work,5 Kam-mermeyer,6 Steinour,7 and others have studied the problem. The writer has no final answer to the thickening story but would like to propose a picture of the mechanics of the two phases of thickening which has been found useful in understanding the subject and which leads to some convenient relationship in treating the compression step and arriving at the compression depth.

Jan 1, 1950

By W. M. McKewan

Magnetite pellets were reduced in flowing hydrogen at pressures up to 40 atm over a temperature range of 350° to 500°C. The rate of weight loss of oxygen per unit area of the reaction surface was found to be constant with time at each temperature and pressure. The reaction rate was found to be directly proportional to hydrogen pressure up to 1 atm and to approach a maximum rate at high pressures. The results can be explained by considering the reaction surface to be sparsely occupied by adsorbed hydrogen at low pressures and saturated at high pressures. PREVIOUS investigation1,2 have shown that the reduction of iron oxides in hydrogen is controlled at the reaction interface. Under fixed conditions of temperature, hydrogen pressure, and gas composition, the reduction rate is constant with time, per unit surface area of residual oxide, and is directly proportional to the hydrogen pressure up to one atmosphere. The reduction rate of a sphere of iron oxide can be described3 by the following equation which takes into account the changing reaction surface area: where ro and do are the initial radius and density of the sphere; t is time; R is the fractional reduction; and R, is the reduction rate constant with units mass per area per time. The quantityis actually the fractional thickness of the reduced layer in terms of fractional reduction R. It was found in a previous investigation2 of the reduction of magnetite pellets in H2-H,O-N, mixtures, that the reaction rate was directly proportional to the hydrogen partial pressure up to 1 atm at a constant ratio of water vapor to hydrogen. Water vapor poisoned the oxide surface by an oxidizing reaction and markedly slowed the reduction. The enthalpy of activation was found to be + 13,600 cal per mole. It was also found that the magnetite reduced to meta-stable wüstite before proceeding to iron metal. The following equation was derived from absolute reaction-rate theory4,8 to expfain the experimental data: where Ro is the reduction rate in mg cm-2 min-&apos;; KO contains the conversion units; Ph2 and PH2O are the hydrogen and water vapor partial pressures in atmospheres; Ke is the equilibrium constant for the Fe,O,/FeO equilibrium; Kp is the equilibrium constant for the poisoning reaction of water vapor; L is the total number of active sites; k and h are Boltzmann&apos;s and Planck&apos;s constants; and AF is the free energy of activation. Tenenbaum zind Joseph5 studied the reduction of iron ore by hydrogen at pressures over 1 atm. They showed that increasing the hydrogen pressure materially increased the rate of reduction. This is in accordance with the work of Diepschlag,6 who found that the rate of reduction of iron ores by either carbon monoxide or hydrogen was much greater at higher pressures. He used pressures as high as 7 atm. In order to further understand the mechanism of the reduction of iron oxide by hydrogen it was decided to study the effect of increasing the hydrogen pressure on rebduction rates of magnetite pellets. EXPERIMENTAL PROCEDURE The dense magnetite pellets used in these experiments were made in the following manner. Reagent-grade ferric oxide was moistened with water and hand-rolled into spherical pellets. The pellets were heated slowly to 550°C in an atmosphere of 10 pct H2-90 pct CO, and held for 1 hr. They were then heated slowly to 1370°C in an atmosphere of 2 pct H2-98 pct CO, then cooled slowly in the same atmosphere. The sintered pellets were crystalline magnetite with an apparent density of about 4.9 gm per cm3. They were about 0.9 cm in diam. The porosity of the pellets, which was discontinuous in nature, was akrout 6 pct. The pellets were suspended from a quartz spring balance in a vertical tube furnace. The equipment is shown in Fig. 1. Essentially the furnace consists of a 12-in. OD stainless steel outer shell and a 3-in. ID inconel inner shell. The kanthal wound 22 in. long, 1 1/2, in. ID alumina reaction tube is inside the inconel inner shell. Prepurified hydrogen sweeps the reaction tube to remove the water vapor formed during the reaction. The hydrogen is static in the rest of the furnace. The sample is placed at the bottom of the furnace in a nickel wire mesh basket suspended by nickel wire from the quartz spring. The furnace is then sealed, evacuated, and refilled with argon several times to remove all traces of oxygen. It is then evacuated, filled with

Jan 1, 1962

THROUGH the courtesy of the Southern Appala-chian Coal Operators&apos; Association, a joint meeting of the Southern Appalachian Efficiency Associa-tion and local members of the A. I. M. E. and A. S. M. E. was held at Knoxville, Tenn., on Nov. 12. In introduc-ing the subject and stating the object of the meeting, H. Foster Bain, speaking for the. Institute members, said "Shoveling coal is the largest job of hand labor re-maining in this country, with the exception of the mis-cellaneous work on the farms, and even there nearly all the big jobs are now performed with the help of machines. The men in the coal mines, by hand labor, dig, each year, more cubic yards than were taken out of the Panama Canal. It has been a natural ambition of engineers, operators and men alike to follow here the characteristic lead of American industry and to substi-tute as far as possible the work of machines for the work of men; to promote the latter to the position of con-trolling and directing mechanical power rather than being themselves the machines that lift the coal from the floor of the room into the mine car. "Handling materials is one of the regular jobs of mechanical engineers, and the American Society of Me-chanical Engineers maintains a Materials Handling Division for discussion of the technical problems con-cerned. Having in mind the excellent results that had flowed from application of mechanical power and de-vices to these problems in factories, port terminals, warehouses, and other above-ground plants, the Me-chanical Engineers began to consider the possibility of introducing similar methods underground. Individual-ly, many were called upon to design, erect and operate machines for such use and at once they found them-selves faced by many novel conditions and difficulties. The Division thereupon planned a general meeting in New York in March, 1926, for consideration of problems and progress in this field. The Mining Engineers. and representative coal operators were invited to attend and

Jan 12, 1927

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 M. A. Bryant, J. C. Goodwin, T. B. Faddies, L. D. Kornze

The Mercur Gold Mine is located 56 km (35 air miles) southwest of Salt Lake City in north central Utah; In July 1981 Getty Mining Company made the decision to put Mercur into production. The first gold bar was poured in April 1983. This paper provides details on: 1) the history of the camp, 2) past production, 3) geology of the deposit, 4) the exploration and development program, 5) ore reserve estimates, 6) detailed geologic pit mapping, 7) production blasthole sampling techniques and 8) the use of geostatistics (kriging) in handling assays and gold extractions to produce the required mill feed.

Jan 1, 1985

By K. U. Snowden, J. N. Greenwood

EARLY studies by Gough and sopwith&apos; have shown that the fatigue resistance of certain metals increased when the test was carried out in a partial vacuum; lead showed this effect to a marked degree. This communication describes surface deformation differences between high-purity lead fatigued in air and in a vacuum of approximately 5 X l0-3 mm Hg. Both air and vacuum tests were carried out by the same alternating flexure machine at a frequency of 500 cpm. Flat cantilever-bend specimens with tapered sides were cut from strip, annealed at 100°C, and chemically polished.

Jan 1, 1959

By G. Carman Ridland

In conjunction with a geological investigation of the silver-bearing veins at Contact Lake, Northwest Territories, Canada, a survey was made with a Geiger-Miiller counter of the gamma-ray emissions from the rocks in the vicinity of the mine workings. Discontinuous pitchblende veins have been encountered occasionally in the silver-bearing fissures, and the geophysical survey was undertaken with the hope that abnormally high gamma-ray intensities, if detected, might lead to larger and more continuous pitchblende discoveries. Before the instrument was used at Contact Lake, preliminary tests were made, first with laboratory specimens at Princeton University, and later over known pitchblende deposits at the Eldorado property, LaBine Point, N.W.T. The Geiger-Müller counter, as adapted for field use, is described; the technique of transporting and operating the instrument is outlined; and the general precautions to be observed are discussed. The results obtained at Great Bear Lake show that the instrument is capable of detecting not only a pitchblende ore shoot in a shear zone, but also the mildly radioactive "host rock" at a considerable distance from the ore body. Hence, use of the Geiger-Müller counter is urged, not just for the detailed search for an ore body in a shear zone, but for the detection of possible radioactive "host rocks" in large-scale reconnaissance surveys of unexplored regions made by prospectors and members of federal geological survey parties. Location.—Along the rocky eastern shores of Great Bear Lake, in the Northwest Territories of Canada, lies one of the world&apos;s great radium-producing areas. The Eldorado mine, owned and operated by the Eldorado Gold Mines, Ltd., is at LaBine Point; while the Contact Lake mine, operated by Bear Exploration and Radium, Ltd. (B.E.A.R.), lies 9 miles to the southeast of LaBine Point and 2 miles south of Echo Bay, an indentation in the eastern shore line of Great Bear Lake. Geology.—The Eldorado company obtains its radium by the mining of the mineral pitchblende, which is found associated with a complex variety of metallic and nonmetallic minerals1 in quartz-carbonate veins occurring in metamorphosed pre-Cambrian sediment aries. Most of the pitchblende is intimately associated with a brown quartz and belongs to an early hydrothermal stage of mineralization during which safflorite-rammelsbergite and minor cobalt-nickel minerals were also deposited. Some pitchblende occurs with a group of minerals belonging to a later stage of mineralization in which the gangue is mainly dolomite and sometimes ferruginous rhodochrosite. Associated with this group are native silver and lead-zinc-copper sulphide minerals. The Contact Lake property owes its existence to the mining of rich, native silver ore shoots, which are

Jan 1, 1946

By G. Carman Ridland

In conjunction with a geological investigation of the silver-bearing veins at Contact Lake, Northwest Territories, Canada, a survey was made with a Geiger-Miiller counter of the gamma-ray emissions from the rocks in the vicinity of the mine workings. Discontinuous pitchblende veins have been encountered occasionally in the silver-bearing fissures, and the geophysical survey was undertaken with the hope that abnormally high gamma-ray intensities, if detected, might lead to larger and more continuous pitchblende discoveries. Before the instrument was used at Contact Lake, preliminary tests were made, first with laboratory specimens at Princeton University, and later over known pitchblende deposits at the Eldorado property, LaBine Point, N.W.T. The Geiger-Müller counter, as adapted for field use, is described; the technique of transporting and operating the instrument is outlined; and the general precautions to be observed are discussed. The results obtained at Great Bear Lake show that the instrument is capable of detecting not only a pitchblende ore shoot in a shear zone, but also the mildly radioactive "host rock" at a considerable distance from the ore body. Hence, use of the Geiger-Müller counter is urged, not just for the detailed search for an ore body in a shear zone, but for the detection of possible radioactive "host rocks" in large-scale reconnaissance surveys of unexplored regions made by prospectors and members of federal geological survey parties. Location.—Along the rocky eastern shores of Great Bear Lake, in the Northwest Territories of Canada, lies one of the world&apos;s great radium-producing areas. The Eldorado mine, owned and operated by the Eldorado Gold Mines, Ltd., is at LaBine Point; while the Contact Lake mine, operated by Bear Exploration and Radium, Ltd. (B.E.A.R.), lies 9 miles to the southeast of LaBine Point and 2 miles south of Echo Bay, an indentation in the eastern shore line of Great Bear Lake. Geology.—The Eldorado company obtains its radium by the mining of the mineral pitchblende, which is found associated with a complex variety of metallic and nonmetallic minerals1 in quartz-carbonate veins occurring in metamorphosed pre-Cambrian sediment aries. Most of the pitchblende is intimately associated with a brown quartz and belongs to an early hydrothermal stage of mineralization during which safflorite-rammelsbergite and minor cobalt-nickel minerals were also deposited. Some pitchblende occurs with a group of minerals belonging to a later stage of mineralization in which the gangue is mainly dolomite and sometimes ferruginous rhodochrosite. Associated with this group are native silver and lead-zinc-copper sulphide minerals. The Contact Lake property owes its existence to the mining of rich, native silver ore shoots, which are

Jan 1, 1946

By F. L. Sizer

The mining regulations of British Columbia and Mexico present some features which might well be copied in the United States, if we are to have a complete revision of the laws governing mining titles. 1. First and foremost is the "squarc" location, which would mean the abolition of extralateral rights. This is a condition in both of the countries above named which has seemed to work no hardship upon any one, and certainly the limitation of underground rights by vertical planes through all lines makes a locator&apos;s rights clear. In view of the long and costly litigation which has involved so seriously many of our most important mining districts, it would seem to be the part of wisdom to avoid a repetition of similar trouble on titles of lode mining claims, by the enactment&apos; of a law similar to that in force in British Columbia. Objections have been raised by .representatives of English companies to the investment of large amounts of money in mining operations in the United States, because of the insecurity of title under the &apos;present apex law; and the statement has been made to me personally by one of the largest English operators, that he would .never again consent to the purchase of mines in the United States, preferring Mexico with all its revolutionary troubles to the danger of encroachment upon his underground rights by an unscrupulous neighbor. Without going into further argument as to the desirability of the I(square location," it should be sufficient to say to those who are inclined to "let well enough alone" and still stick to the "law of the apex" that there have never been any serious objections raised to this feature of the square location in either British Columbia or Mexico. There are well founded and logical reasons for abandoning the doctrine of extra-lateral rights since it is so difficult of interpretation; the most natural substitute being a law similar to that of British Columbia, giving to each locator an area 1,500 ft. square. I would advocate the right to locate adjoining claims of equal extent on either side of the discovery claim, on the strike of the lode, subject to a seasonable requirement in the matter of work upon them; and in the case of a vein dipping flatter than 45&apos; from the horizon, or in case of a

Jan 1, 1915

By Lawrence Henderson

TO increase tonnage in the early days of coal mining it was necessary only to hire more men. The job now is to increase the tons per man, but other troubles arise because this has been accomplished. With the introduction of continuous miners, newer and faster loading machines, and faster belt conveyors the safety engineer has been faced with new difficulties. Use of larger equipment created roof control problems, which were thoroughly studied by the safety engineers of various companies. With the assistance of the U. S. Bureau of Mines, safety engineers in Alabama conducted roof bolting experiments wherever they appeared to be applicable. Accident records before and after the method was adopted showed results more than justifying the efforts and funds expended. The larger mining companies responded enthusiastically to the program because roof bolting not only prevented accidents but also increased production efficiency, in many cases rep- resenting the margin between profit and loss. In Alabama today there are miles of roof supported by bolts.

Jan 8, 1957

By Frederick O?Neil

SCOPE OF THIS REPORT THE object of this paper is to describe the present status and possibilities of liquid oxygen as an explosive based upon the investigations, research and practical work of the Ingersoll-Rand Co., and of the Air Reduction Co., from early in 1922 to date. The following work was done. 1. A study of the history and physical theory of L. 0. X. as an explosive. (No attempt will be made in this paper to give the history or theory, as this has already been covered by the literature on the subject.) 2. An investigation of the use and the practice with L. 0. X. in the iron mines of Lorraine where L. 0. X. has its largest application in Europe. Although L. 0. X. is extensively employed in the; iron mines of Lorraine, many of the mines using it exclusively, and blasting with it a total of approximately three million tons of iron ore per year, the fact that the mining practice in Lorraine1 is to drill comparatively shallow holes and blast only a few holes at a time, renders the data obtained there of very little value in estimating the possibility of replacing dynamite with L. 0. X. in American mining methods. In fact, in the iron mines in Lorraine, L. 0. X. replaced black powder, or its equivalent. 3. Laboratory research work on properties of absorbent materials. 4. Work in the Bureau of Mines explosive laboratory at Pittsburgh, Pa., on the properties of L. 0. X. cartridges. 5. Practical work underground with L. 0. X. cartridges in the Witherbee-Sherman iron mines at Mineville, N. Y. 6. Practical work in the quarries of the Calcite Quarry Co., Myers-town, Pa. 7. Practical blasting in several quarries and open-pit mines.

Jan 2, 1926

By David White

THE environmental conditions under which coals are deposited are revealed by the stratigraphy of the coal basins and coal beds and by the details of the structure and the physical constitution of the coals themselves. THE LAND SURFACE Generally Low Relief or Base Level In the Paleozoic coal fields, which have longest been worked, are most important, and are best known, we find relations, in general, as follows A post-Mississippian uplift with, in most cases, very moderate deformation, followed by erosion by which the uplifted regions, especially the bolder of the new topography, were largely worn down, while the older and less deformed regions were more or less extensively base leveled. Base leveling of most of the region continued as the deposition of coal measures proceeded. Consequently, in most coal fields the Pennsylvanian, or upper Carboniferous, lies unconformably on the Mississippian or on older formations. There are but few regions in which sedimentation is seen to have been apparently continuous from the Mississippian into the Pennsylvanian ("Coal Measures").

Jan 1, 1925