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By William Glenn

Almost beyond doubt, the most important contribution to the assaying of copper yet made, is that of Mr. Eustis (Bans., xi., 120) on the " Comparison of Various Methods of Copper Analysis," which indicates in a manner for which the assayer cannot but feel grateful, how a copper sample ought to be treated from the moment it enters the laboratory until the copper is finally weighed. Admitting, as the present writer is inclined to do, that this paper establishes, as the official standard, the method of electrolysis, we may note as one of the few details which it does not finally fix, the kind of battery most desirable for precipitating the copper upon platinum. In this respect each assayer appears to be a law unto himself, while all feel more or less " shaky " as to the results. Classsen seems to suggest a remedy when he directs the measuring of the -gases liberated by the battery employed. But, in fact, that measure is not a constant in the Bunsen elements which he prescribes for copper determination. Furthermore, measuring gases necessitates more machinery and labor than the average assayer has a stomach for. It is, however, but just to Classen, to whom we owe so much, to reeall that he wrote more especially for students in the schools.

Jan 1, 1889

By Arthur Redfield

THE West Indies are the summits of a submerged, mountain chain, the continuation of which must be sought in the mountains of central Honduras. In Haiti, the chain divides, one branch passing through Jamaica and the other through Cuba, the Cayman Islands, and the Misteriosa bank. Suess divides the West Indies into three zones: The first zone is entirely of volcanic origin and includes many recent volcanic cones. It includes the arcùate string of islands, which extends from Saba and St. Kitts to the Grenadines and Grenada. The western half of Guadeloupe belongs to this group. The second zone consists of a geanticline, of which the sedimentary rocks range from the Jurassic to the Quaternary, but consist chiefly of Lower Tertiary sediments. In the west it is broad, including the whole of the Greater Antilles; but in the east it is restricted to a narrow belt, which includes the Virgin Islands (except Anegada), Anguilla, St. Bartholomew, Antigua, the eastern part of Guadeloupe and part of Barbados. The islands that compose the third zone are flat and low. Like the second, this zone is broad in the west and narrow in the east; it includes the Bahamas, Anegada, Sombrero, Barbuda, and part of Barbados. Geologically, Florida and the plain of Yucatan may be regarded as belonging to it. Trinidad and Tobago, though-geographically adjacent to the Lesser Antilles, are geologically a detached part of the South American continent. The crystalline complexes of northern Trinidad and of Barbados are a continuation, en echelon, of the crystalline axis of the promontory of Paria. The folded Cretaceous and Tertiary of the central and southern parts of Trinidad represent a continuation of the folded sediments of the Paria district of Venezuela.

Jan 6, 1922

By H. H. Stoek

A STUDY of American coal mine practice shows two of its distinctive features to be: A greater number of accidents per thousand employees than in any of the other leading coal-producing countries; a much greater percentage of the coal lost than is the case in any of the other leading coal producing countries. Although our subject is mainly concerned with the second feature, any consideration of mining methods should include safety, efficiency, and economy or costs. If in defense of our wasteful mining the argument could be offered that it was necessary on account of safety, and that it is carried out with less loss of life than is the case in other countries the plea for conservation of coal could not be so strongly urged. But when we are wasteful of both life and property, the subject merits more consideration than it has received. Some coal operators will doubtless say that the unit of accidents should be the number per million tons produced rather than per thousand employees, for by adopting this unit America probably stands in the lead rather than the lowest among the countries. However, vital statistics are not usually so expressed by other governments, by life and accident insurance companies, or in other industries, and it is merely begging the question and attempting to bolster up a bad condition to adopt a peculiar unit for the statement of our accidents. For many years the statement was made by various agencies, and was unchallenged, that "For every ton of bituminous coal mined in the United States a ton had been lost in the way of pillars left in the mines." This statement was undoubtedly true for many years, and although some progress has been made in the past decade looking to a higher extraction, and in some districts very decided progress, the loss is still great; and, although no exact data can be given, it is probable that for the United States as a whole at- least one ton is lost for every two mined.

Jan 2, 1922

By H. F. McCullough

The success of a coal-mining venture as relates to operations at the gob or break-line, such as the drawing of pillars or the working of long-faces, depends upon the control of face conditions. The measures required to control the latter are dependent upon the action of the coal seam, roof and floor at and in the vicinity of the faces, but the manner in which these will act is dependent upon the rate of face movement as well as upon the facc characteristics and upon the forces exerted. Yet the merits of a method of working—the practicability of controlling face conditions and the means required for such control when applied to any particular case—are usually judged only upon a consideration of the characteristics of coal seam, roof and floor, and the manner in which they have been observed to act. Practically every coal-mining man knows that face conditions are influenced by the rate of face movement, but few have appreciated that this is as much of a factor in the control of face conditions as are the face characteristics and the forces exerted. Fewer yet have recognized or taken advantage of faster rates of face movement as one of the principal means of establishing control of face conditions or of securing more favorable face conditions. Seemingly inherent difficulties, particularly in the control of roof conditions, but also in the control of conditions of the coal seam and floor, are frequently mitigated or disappear when the rate of movement of the faces is sufficiently increased. The characteristics of the coal seam, roof and floor and the forces exerted upon them do determine the general trend or tendency of face action, but the manner in which the coal seam, roof and floor will act and be aeted upon and the magnitude of the action during the time the site of mining operations remains at any particular point are very largely determined by the rate of movement of the faces. Progressive Nature of Forces Exerted Coal seam, roof and floor are composed of materials having definite properties or characteristics. The potential or ultimate values of the

Jan 1, 1927

By Howard R. Hughes

In drilling for water and oil to reasonable depths through the generally soft yielding clay and sand formation of the Coastal Plain of Texas, Louisiana, and Mississippi, the rotating method of drilling was adopted, principally on account of the easy and quick penetration, and the low cost of the drilling plant. In favorable ground, free of heavy gravel and rock strata, as much as 1,600 ft. has been drilled in less than 36 hr., although such performances were of course rare. Hydraulic rotary drilling, or, as it is now called, rotary drilling, was used in the above States as early as 1880. The plant consisted of an ordinary derrick, a 25-h.p. boiler, a small hoist, a steam pump, and a water swivel with hose attachment, and an ordinary flat diamond-pointed bit. The successful drilling in of a phenomenal oil well by this process on Spindletop, near Beaumont, Texas, on Jan. 10, 1901, and the ascertained impracticability of drilling subsequent wells in the same locality by other methods (owing principally to heavy quicksand under pressure from below), brought rotary drilling into great prominence, practically to the exclusion of any other process throughout the Coastal Plain, and later on elsewhere. The method, as its name implies, involves the rotation of a pipe by means of machinery placed on the derrick floor. A drill bit attached to the lower end cuts a clearance for the drill pipe, with much the same motion and effect as an auger. Water forced through the drill pipe by means of a pump, and escaping through the bit, removes the cuttings and returns to the surface outside the drill pipe. In this manner the hole is kept open, permitting the drill stem to rotate freely. The pressure of the column of muddy water holds up the walls of the hole until it has been cased. Practically all the wells of the Gulf coast region, numbering nearly 10,000, have been drilled with this system. During the last five years its use has been extended to many other States and countries.

Jan 1, 1915

By R. F. Mitchell, G. F. Dillon, A. F. Armington

In this paper the present methods of boron preparation are discussed with emphasis on the iodide intermediate. Several methods of boron triiodide preparation were investigated, the most satisfactory method being the preparation from the elements. A yield of 60 pct based on iodine is found for this method. Zone-refining, sublinzation, distillation, and fractional-recrystallization results are given for the boron triiodide, with distillation producing the best results. Several methods of decomposition are also discussed. The purity of the resulting iodide boron approximates the puritjl of the best available bromide boron, ELEMENTAL boron has been suggested as a possible high-temperature semiconductor by several workers,' but has never been exploited as a device material. The principal difficulty with boron is the unavailability of pure crystalline material from which accurate information on electrical properties could be obtained. Most boron crystals presently produced are very imperfect in structure and of questionable purity, particularly in relation to carbon content. Several methods of boron purification have been reported in the past few years, all of which produce material with a purity better than 99.0 pct. Most of these methods have been the subject of a recent review by Starks' and will not be elaborated upon in this report. However, of all the purification methods reported, only those using halide intermediates produce a purity approaching that usually required for electronic applications. The bromide intermediate has been most used for the preparation of high-purity boron.'y3 This material is easily prepared from the elements and can be effectively purified by distillation and decomposed by hydrogen reduction. The resulting product contains a trace of silicon, and an uncertain amount of carbon, believed to be approximately 100 ppm. It has been recently reported by Russian workers that high-purity boron can be produced using an iodide intermediate.' In the work cited, boron is reported free of spectro-scopically determined impurities, but the reported detection limits are quite high (- 100 ppm). In addition, no data is given on the carbon content of the product. In the present paper, boron triiodide was chosen as the intermediate for several reasons. First, carbon tetraiodide, which could be a major impurity, is reported to be unstable above 200" and hence could be easily separated from the boron triiodide by its decomposition, since temperatures greater than this are attained during the purification process. The low melting point (45°C) and boiling point (20B°C) and the relatively high vapor pressure of boron triiodide should allow the application of any physical purification technique to the material. The possibility of a lower decomposition temperature than that used for the bromide process is another advantage which might cut down extraneous contamination. The iodide, however, does have certain disadvantages when compared with the bromide, the production cost being the most significant. This is the result of a higher halide-to-boron weight ratio, which means more intermediate must be employed. The cost of the starting material is also greater for the iodide. This cost could be considerably reduced however, by recycling the iodine byproduct. Epitaxial growth of boron, which is probably the best method of producing junctions, should be possible with either the bromide or the iodide as the intermediate. However, this has been attempted only on a limited scale up to the present time because of the unavailability of good crystals. The authors have been relatively successful in laying down a heterotaxy of boron on silicon, however. This will be reported at a later date. Several crystalline modifications have been reported for boron, four of which are now believed to be real.' These are the a! and 0 rhombohedral and the a, and 0 tetragonal. In general, the a! rhombohedral is the low-temperature form and the B rhombohedral is the high-temperature form. The tetragonal structures are detected between 1000"

Jan 1, 1964

By Charles A. Lindberg

It will be generally agreed that the most important accessory to a rail haul operation is the railroad type locomotive crane. The oldest and still most common type is the steam crane, a self-contained steam power plant, coal fired, complete with boom and hoisting machinery and mechanical drive capable of propelling the unit on its own power at speeds up to 15 mph on the level, and hauling, if necessary, a car for transport of the objects being handled. Usually, for greater mobility and safety, this crane and flatcar are moved around the pit by a switcher locomotive. Crane capacities range from 25 to 40 tons, these loads being handled with the shortest radius of boom and with outrigger. Boom lengths are 55 to 60 ft long, usually with heavy lift main blocks at 40 ft boom lengths. Lifting capacities with booms at maximum radius are approximately 20 % of maximum rating. Free capacities, namely without outriggers, range from 65 (at minimum radius) to 55% (at maximum radius) of the above capacity values.

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