Search Documents

G. F. COMSTOCK (author's reply to discussion *).-The discussion of this paper has been of such volume and interest as to constitute in itself a sufficient excuse for the paper, even though the paper itself may have been as much in error as some of its critics have maintained. Mr. Howard does not appear to realize some very practical facts that the opponents of his theory have advanced. Among these are: the coarsely crystalline fracture of the nucleus of a transverse fissure, so different from the smooth fatigue break around it; the occurrence of fissures in large numbers in certain heats or rollings of rails, while other heats or rollings do not develop them; and the much smaller proportion of transverse fissures found in rails rolled .from reheated blooms as compared with direct-rolled rails. These facts are not explained by Mr.

Jan 6, 1919

By G. T. Horne, P. J. Wray, S. Kinoshita

CONSIDERABLE evidence exists for a strengthening mechanism operative at intermediate temperatures in bee metals containing interstitial solute atoms. The strengthening is indicated by a maximum in the ultimate tensile strength1 as well as the fatigue

Jan 1, 1965

The suggestions of the members of the Institute are very much desired by the Committee on Nominations prior to deciding upon its nominations to fill the places of those officers who retire early in 1917. The Committee must make its final report to the Board of Directors early in October. The members are, therefore, asked to send in promptly their suggestions for Directors as well as for Vice-Presidents and President. The Committee hopes to hear from a large number of the members. The officers to be elected at the annual meeting in February, 1917, are: One officer, known as Director and President. Two officers, known as Director and Vice-President. Five officers, known as Director. The attention of members is called to Articles V and VII of the Constitution, and to By-Law XIII, which reads as follows: "The geographical districts to be considered by the Committee on Nominations shall be as follows, until otherwise ordered by the Board. District No. 1. New England, New York, and-New Jersey, excepting New York City and district, which is provided for in the Constitution. (N. B.-New York City and district is designated District 0.)

Jan 7, 1916

LIST OF THE MEETINGS OF THE INSTITUTE AND THEIR LOCALITIES FROM ITS ORGANIZATION Transactions Number Place Date Vol Page I Wilkes-Barre, Pa * May, 1871 I 3 II Bethlehem, Pa August, 1871 I 10 III Troy, N Y November, 1871 I 13 IV Philadelphia, Pa February, 1872 I 17 V New York, N Y * May, 1872 I 20 VI Pittsburg, Pa October, 1872 I 25 VII Boston, Mass February, 1873 I 28 VIII Philadelphia, Pa * May, 1873 II 3 IX Easton, Pa October, 1873 II 7 X New York, N Y February, 1874 II 11 XI St Louis, Mo * May, 1874 III 3 XII Hazleton, Pa October, 1874 III 8 XIII New Haven, Conn February, 1875 III 15 XIV Dover, N J * May, 1875 IV 3 XV Cleveland, 0 October, 1875 IV 9 XVI Washington, D C February, 1876 IV 8 XVII Philadelphia, Pat June, 1876, V XVIII Philadelphia, Pa October, 1876 V 9 XIX New York, N Y February, 1877 v 27 XX Wilkes-Barre, Pa * May, 1877 vi 3 XXI Amenia, N Y October, 1877 vi 10

Jan 1, 1910

By W. C. Kerr

When Agassiz and his party of geologists commenced their exploration of the interior of Brazil and the Amazon region, one of the first and, to the last, one of the most novel and striking phenomena which met them everywhere was the great depth of decomposed or partially decayed rock in situ, which mantles, and for the most part conceals, the underlying strata. The same facts strike all geological observers from the North who happen to penetrate the middle and southern latitudes of the Atlantic States. In North Carolina, e. g., the entire middle and western regions, outside of the Quaternary clays, sands, and gravels of the East,—that is, all that portion of the State occupied by the Archæan and Mesozoic rocks,—show everywhere this peculiarity, so new to those accustomed to glaciated surfaces. Not only do the hills and slopes, the mountain chains and

Jan 1, 1880

Safety and health are no longer secondary responsibilities but must be of paramount concern to every mining operation, according to Anthony J. Thompson, an attorney with Hamel, Park, McCabe & Saunders of Washington D.C. The Mine Safety and Health Administration (MSHA) forecasts an estimated 19,000 inspections during 1979, and the economic and psychological impact of these inspections may he significant. To illustrate his point Thompson reviewed the experiences of a relatively large operation during a recent MSHA visit. The inspector was on the premises for two months, issuing between 250 to 300 "significant and substantial" (s&s) citations. During the most intensive period, about one month in duration, the operation experienced a production loss estimated between 2500 to 3000 tons; an accident rate up 30% over the previous month and 20% over the same month in the preceding year; 100% of the safety director's and safety engi¬neer's time was devoted to the inspection; 50% of top level management's time; and 90% of the mid-level or front line supervisory's time.

Jan 11, 1979

By Herbert C. Hoover

While the importance of the superficial alteration of golddeposits is recognized in pure science, it seems often to be singularly disregarded among engineers in practice. Its great practical bearing lies in the exploitation of new regions; and nowhere are the disastrous results of ignoring it more vividly shown than in Western Australia, where the impoverishment of the ores, and their frequent transition from free-milling' to refractory character in depth (things, as a rule, neither anticipated nor ascertained by exploration beforehand), have brought many companies to ruin, or caused the loss of much money squandered on machinery adapted only to temporary conditions.

Jan 1, 1899

By W. Buchanan, O. Johari

STEREOGRAPHIC projection has been one of the most useful aids in crystal-structure studies. With the increasing use of electron microscopy in metallurgy and other fields, stereographic projection is being used in many ways1 to interpret the results from electron diffraction patterns and transmission micrographs. For many of these applications, e.g., trace analysis, twinning, and so forth standard projections of various indices are required.

Jan 1, 1967

By D. N. Williams

THE present study was undertaken with two specific objectives: measurement of the thermal-expansion coefficient of ß titanium and examination of the effect of solid-solution alloying on the thermal expansion coefficient. Four titanium alloy niaterials were available in the form of annealed 5/8-in. diam rod. Three of these, Ti-8V, Ti-20V, and Ti-6A1-4V, were prepared in the laboratory from 140 Bhn sponge. The

Jan 1, 1962

By William G. Pariseau

The extraction ratio approach to pillar design in flat seams is based on a mathematically exact analysis that is a reasonable physical approximation to room-and-pillar layouts in many instances. The essentials of the approach are reviewed and then mathematically approximate formulas for pillar design in inclined seams of arbitrary dip are proposed. Detailed numerical analysis of stress about a typical 5 entry, 4 pillar panel at dips of 0, 15, 30, 45, 60, 75 and 90 degrees at low and high extraction ratios show that the proposed inclined seam extraction ratio formulas for pillar normal and shear stresses, although conservative, have an accuracy quite adequate for engineering purposes. Appropriate pillar safety factors for compressive and shear failure and a safety criterion for overturning are specified.

Jan 1, 1982

By Charles F. King

The only investigations on record of the reactions occurring (luring the Bessemer blow are of charges containing a large percentage of manganese, with the exception of' two partial analyses by Snelus and Barker of the English method, where a low percentage of manganese was used. They do not give the analysis of the spiegel, [lor do they report any graphitic carbon after the first stage of the process. Both report only traces of manganese after the first stage until the addition of spiegel. The slags corresponding to the samples of metal were not analyzed.

Jan 1, 1881

W. H. BLAUVELT (author's reply to discussion *).-The prevention of smoke from byproduct-oven plants is not as simple as would appear from Mr. Moss's statement. All well designed byproduct-oven plants are equipped with ample exhauster capacity, and the suction on the ovens is controlled by highly sensitive pressure governors that control the pressure within a fraction of a millimeter. Of course, this apparatus can get out of order, causing the batteries to smoke, but this does not often happen. As stated by Mr. Thompson, the smoke produced is made almost entirely during the time of charging the ovens, when they are cut off from the hydraulic main. The amount of smoke that escapes at this time is extremely small, compared with -the amount produced by a beehive-oven plant, but the mechanical difficulties in preventing any escape of smoke at charging time are considerable. Several devices are in operation at a number of plants which collect most of the smoke made during charging and several devices are being worked on for its complete

Jan 12, 1918

Papers in Classes A-Metal Mining, B-Milling and Concentration, H-Indus¬trial Minerals, and I-Mining Geology are distributed in MINING TECHNOLOGY, which is issued every other month. Papers in Classes C-Iron and Steel Division, D¬-Nonferrous Metallurgy and E-Institute of Metals Division are distributed in METALS TECHNOLOGY, which is issued twice quarterly. Papers in Class G-Pe¬troleum Division are distributed in PE¬TROLEUM TECHNOLOGY, which is issued every other month. TECHNICAL PUBLICA¬TIONS in Classes F-Coal Division, J¬-Mineral Industry Education Division, K¬-Mining Administration, and 1-Geophysics, are issued as separate pamphlets. Contributions are papers that when printed or mimeographed are available but only on request.

Jan 1, 1943

The history of surface mining is essentially that of mining coal, copper, and iron ores and the non- metallic minerals, i.e. clays, gypsum, phosphate rock, sand, gravel and stone. The accompanying table comparing world production with that of the U. S. indicates that two thirds of the 8.8 billion tons of ores mined throughout the world come from surface operation. Assuming that the stripping ratio for surface mining in the U. S. applies equally to world production, then over 21 billion tons of waste, or a total of nearly 27 billion short tons of material are mined annually in the world by surface methods. Several factors are significant indicators of economic and technologic trends in surface mining. Among these are increasing production, a shift in emphasis from underground to surface mining, a decline in the grade and quality of some crude materials and, with few exceptions, an increase in the productivity of labor.

Jan 10, 1967

By D. W. Brunton

The erection of large metallurgical establishments for the treatment of gold, silver, copper, and lead-ores, at railroad arid topographical centers, where fuel and fluxes, together with proper oremixtures, can be cheaply and constantly obtained at all seasons of the year, has led to the very general introduction of a system of ore-handling known as "public sampling." By this system the ore, instead of being shipped direct to the mill or smelter, is sent to a public sampler, where it is crushed and sampled. Guaranteed samples are sent to the different metallurgical establishments, and the ore is then sold to the highest bidder. Though differing in many respects from the English system of "ticketing," the underlying principle is nearly the same, while the greater rapidity with which a lot of ore can be disposed of renders

Jan 1, 1885

By Miroslaw Hajdasinski

Estimation of the economic effectiveness of industrial development projects including mining ones is generally made on the basis of the discrete model of the value changes in time, although the character of these changes is similar to the continuous model. In this paper an attempt has been undertaken to investigate the problem of the value equivalence of both models exemplified by a construction of an underground coal mine. An effort has been made to determine the errors which for different estimation criteria appear in result of the application of the discrete model. Theoretical considerations have been supplemented with practical conclusions.

Jan 1, 1977

By John H. Puffer, Andreas H. Vassiliou

The Bemco mine area is within the Precambrian igneous and metamorphic rock terrain of the New Jersey Highlands province. Rocks In the area include a pyroxene granite, a hornblende granite, a quartz-oligoclase gneiss and a pegmatite and its host rock, a lens of amphibolite which becomes a sulfide-rich pyroxenite near the ore zone. The ore-bearing zone occurs along the hanging wall and foot-wall contact of the pegmatite which was emplaced discordantly into the amphibolite-pyroxenite.

Jan 1, 1985

By Maximo Monte-Flores

A PERUSAL of the most recent literature on the subject of hydrocarbons reveals that one point seems, to have been neglected by the various theories; that is, the influence of the bed-rock on the accumulation and distribution of oil and gas. This can be seen from the following statement of the principles of the most accepted theories. ANTICLINAL THEORY The anticlinal theory claims that the accumulation of the hydro-carbons in deposits of commercial importance was brought about by the gravity of the hydrocarbons, the oil and gas being forced to the top of the porous stratum by the difference of the specific gravity of the hydro-carbons and the water. The principal factors toward the accumulation were the general stratigraphic condition of the rocks, their texture and porosity, and their water content. This theory advocated the preexistence of structural deformation as the basis of the motion of gravity, thus implying the principle that the forces that have caused the deformation have had no influence on the movement of the hydrocarbons. STRUCTURAL THEORY According to the structural theory, the accumulation is due, chiefly, to the structure of the subsurface rocks and differs from the anticlinal theory, mainly, in not considering that the motion of the liquids have been caused by the force of gravity.

Jan 1, 1920

By James E. Lawver

A SURVEY of Minerals Beneficiation Div. membership indicated genuine interest in automatic process control, but revealed that the average mill is operating with a minimum of self-regulating devices. Apparently, the mill operators are content to continue without controls until the practicality of self-regulating devices is more generally accepted, or, in the opinion of the writer, until automatic controls become a necessity to meet economic demands of product quality and cost. Both to stimulate interest in control, and to solicit publication of technical know-how by members and equipment manufacturers, this paper presents a cross section of control problems in two general categories: (a) Control problems that can usually be solved by reference to the literature, i.e. controls that have proven successful in the mineral or chemical industries; (b) Problems that are troublesome and frequently unsolved due to unavoidable adverse conditions in the mill circuit to be controlled.

Jan 10, 1953

Jan 1, 1907