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By William J. Coulter

WITHIN the United States the problem of meeting maximum production by our metal mines has been solved by: (1) Conservation of man power by mechanization. (2) Increasing man-power efficiency as expressed in tons per man-shift by the adoption of new and more efficient methods. (3) Production from submarginal properties made possible by some form of government subsidy. (4) Selective mining of high-grade areas. (5) Drawing on broken ore reserves and reducing advanced development work to a minimum. (6) Making maximum use of available equipment. (7) Repairing equipment that normally would be replaced. (8) Working a seven-day week on a three-shift basis to get maximum use of equipment and man power. (9) Adoption of incentive plans to increase maximum efficiency and unit production. (10) Important advancement in metallurgy, resulting in larger recoveries. (11) Improvements in safety, health, and general working and living condi-

Jan 1, 1945

By R. I. Jaff, H. R. Ogden, D. J. Maykuth

A phase diagram for alloys containing from 0 to 66.9 pct Mn was determined. Two compounds, tentatively labeled 6 and y, were found in this range. The 6 compound is located at about 66.9 pct Mn and melts congruently at 1330°C. The ? compound has a composition near 53 pct Mn and originates in a peritectic reaction at 1200°C between liquid and 6. ß and Y enter into a eutectic reaction at 1175°C. The ß phase field terminates in a very sluggish eutectoid reaction between a and ? at 550°C. MANGANESE is one of the important alloying addition elements to titanium. As a ß-stabiliz-ing addition for a-ß and ß alloys, it provides high strength with adequate ductility.' Two of the earliest commercial alloys contain manganese as a major alloying component.' The earliest published data on the constitution of Ti-Mn alloys was that of Wallbaum,~ who reported the existence of the compound TiMn2. The transformation range of commercial-purity Ti-Mn alloys was investigated by Craighead, Simmons, and Eastwood' who found limited a solubility and a lowering of the ß transus to about 790°C at 7 pct Mn. Preliminary work by the authors of this paper, using high-purity titanium, confirmed the ß-stabilizing action of manganese and showed the existence of several intermediate phases in the Ti-Mn system." More recently, McQuillan3 determined the ß transus temperatures for high-purity Ti-base alloys containing up through 4.4 pct Mn. These data are given in Fig. 1. The present investigation covered alloys made with a high-purity base. The constitution of titanium-rich alloys made with commercial titanium has been reported4," by Holladay, Kura, and Jackson. The alloy range covered in the present investigation was from 0 to 69.5 pct Mn. This alloy range extends slightly beyond the composition of the first congruent-melting compound encountered on proceeding from the titanium end of the system. A description of the materials and methods used in the determination of the diagram is given in the Appendix. The partial phase diagram determined for the Ti-Mn system is shown in Fig. 2. Details on equilibria in the titanium-rich alloys are given in Fig. 3. Liquid-Solid Relationships Observations on the cast structures of the arc-melted ingots showed that the terminal solid solution of manganese in ß titanium enters into a eutectic reaction with an intermetallic compound labeled ?. As will be shown later, this compound has a composition around 53 pct Mn. The eutectic reaction temperature was determined as 1175°C by thermal analysis which also showed that the ? phase originates in a peritectic reaction at 1200°C. Fig. 4 shows typical eutectic structures for alloy compositions on both sides of the eutectic composition which is located at 42.5 pct Mn. In alloys over the range of 45.4 through 69.5 pct Mn, a second intermetallic compound, labeled 6, was identifield as the primary phase. This phase consistently increased in amount as the manganese content approached 66.9 pct, and, as shown in Fig. 5, an alloy structure containing 66.9 pct Mn consisted essentially of the 6 compound. Thermal-analysis data indicate a melting point of about 1330°C for the 6 intermediate phase. At 67.0 pct Mn, small quantities of a new, higher manganese-content phase were observed in the form of Chinese-script eutectic particles. Comparison of Fig. 6a and b shows an increasing quantity of this phase as the composition was increased to 69.5 pct Mn. The formation of peritectic ? in arc-melted alloys containing 45.4 pct Mn and above appears to be almost entirely suppressed, as shown in Fig. 7a and b. This is because of the narrow freezing range available for its formation by peritectic reaction and because of the very high cooling rates obtained in

Jan 1, 1954

By Christopher Haycocks, Lawrence P. Johnson, George M. Neall, James M. Townsend

No method of roof control yet devised has proven to be universally acceptable for the wide range of strata conditions experienced in U. S. coal mines. However, a relatively new innovation, the roof truss, has proven itself capable of preventing roof failures which both conventional and resin bolting could not. Presently, the economics of roof trusses are not favorable when compared to bolting due primarily to drilling and installation procedures, but this is expected to change with improved truss and equipment designs. To realize the full potential of this new method of roof control, design criteria are needed which can optimize the effect of the truss for varying strata conditions.

Jan 6, 1978

By W. D. Keller

THE high-alumina clays of Missouri are interesting for several reasons. They are the only sedimentary deposits in North America of first grade (over 70 pct A1,0,) diaspore and boehmite sufficiently large to be mined commercially. Mineralogically, they are composed of diaspore and boehmite in intimate coexistence, but gibbsite, the common hydrated alumina mineral in bauxite and laterite, is absent, or is exceedingly scanty if present.* Therefore, the Missouri high-alumina clays do not represent typical laterization. The physical chemistry leading to their mineral genesis, and the geolbgical setting for their formation, present important problems for scientific study. The origin of the Missouri high-alumina clays has been discussed in earlier reports by Allen1 (1935) and McQueen 8, 9 (1929, 1943). These investigations were made under difficult conditions, however, because no diaspore deposit had been opened where a Paleozoic (Pennsylvanian) rock cover lay undisturbed over the high-alumina clay. The relationship of the clay to only the underlying rocks could actually be observed. Lacking the guidance of critical postdepositional geologic evidence, undue and erroneous emphasis was placed on the postdepositional leaching of the deposits in the theories on the origin of diaspore and boehmite from clay (hydrous aluminosilicates) . With new geologic evidence at hand, a clearer picture can be made for the origin of the Missouri high-alumina deposits. In this paper the geology of a diaspore deposit whose original Paleozoic cover had not been eroded will be described and interpreted genetically. The close relationship of boehmite and diaspore (also with kaolinite and a chloritic mineral), will be established. A theory of origin for the high-alumina clays, consistent with the new data, will be postulated.

Jan 1, 1952

By Fred Bond

This paper is a continuation of two earlier papers,1,2 and presents new data on the grindability of various ores and other materials-the results of several years of intermittent research work on the nature of grinding and interpretation of test results. It is divided into five parts: 1. The tabulated results of several hundred grindability tests on a wide variety of ores. 2. A method of correcting screen analyses and calculating from them the surface and other properties. 3. A description of a. new method of measuring the "surface energy" of in ore by pendulum impact tests. 4. Test results. 5. A general discussion of the test results and their application to grinding problems.

Jan 1, 1938

By David Turnbull

STAFF: Editor, Gerhard Derge Carnegie Institute of Technology Schenley Park Pittsburgh 13, Pa. Editorial Assistant, M. A. Redmerski Production Editor, Otto T. Johnson THE METALLURGICAL SOCIETY: J. S. Smart, Jr., President; C. C. Long, Past-President; K. L. Fetters, Vice President; T. D. Jones, Treasurer; R. W, Shearman, Secretary. PUBLICATIONS COMMITTEE OF THE METALLURGICAL SOCIETY: C. L. McCabe, Chairman; H. L. Bishop, K. L. Fetters, J. J. Harwood, W. A. Krivsky, F. C. Langenberg, R. E. Lund, W. O. Philbrook, L. L. Seigle, R. L. Smith, and F. L. Vogel. Review and selection of monuscripts is under the supervision of the following Publications Committees: Extractive Metallurgy Division: C. L. McCabe, Chairman; R. E. Lund, Vice-Chairman; D. H. Baker, Jr., W. A. Krivsky, R. A. Lewis, Paul Queneau, A. S. Russell, R. E. Shinkoskey, W, W. Stephens, and M. E. Wadsworth. Institute of Metals Division: L. L. Seigle, Chairman, Paul A. Beck, I. I. Bessen, J. 0. Better-ton, Jr., J. B. Clark, R. S. Davis, A. E. Dwight, R. W. Fountain, R. B. Gordon, C. D. Graham, Jr., R. W. Guard, J. C. Gurland, E. L. Harmon, J. J. Heger, A. A. Hendricksan, M. Herman, J. N. Hobstetter, H. H. Johnson, Jr., R. R. Nash, T- N. Rhodin, R. H. Richman, W. Ros-toker, P. G. Shewmon, C. W. Spencer, L.SIifkin, J. K. Stanley, C. D. Starr, and H. C. Stumpf. Iron and Steel Division: H. L. Bishop, Chairman; R. E. Boni, F. C. Langenberg, J. B. Wagstaff, and T. V. Wainwright. Published bimonthly by the American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc., 29 West 39th Street, New York 18, N. Y. Telephone: PEnnsylvania 6-9220. Subscription $20 per year for non-AIME members in United States and North, South, and Central America; $25, foreign; $5 for AIME members. Single copies, $4.00, single copies foreign, $5.00. The AIME is not responsible for any statement made or opinion expressed in its publications . . . Copyright 1961 by the American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc. . . . Registered cable address, AIME New York .. . Indexed in Engineering Index, Industrial Arts Index, and Chemical Abstracts . . . Second class postage paid at New York, N. Y., and Ann Arbor, Mich. Volume 221, Number 3.

Jan 1, 1962

By AIME AIME

Council. * PRESIDENT OF THE COUNCIL. JAMES F. KEMP NEW YORK, N.Y. (Term expires February, 1913.) VICE-PRESIDENTS OF THE COUNCIL. S. B. CHRISTY BERKELEY, CAL. W. A. LATHROP PHILADELPHIA, PA. GARDNER F. WILLIAMS WASHINGTON, D. C. (Term expires February, 1913.) KARL EILERS NEW YORK, N. Y. WALDEMAR LINDGREN WASHINGTON, D. C. BENJAMIN B. THAYER NEW YORK, N. Y. (Term expires February, 1914.)

Mar 1, 1912

By AIME AIME

COUNCIL.* PRESIDENT OF THE COUNCIL. JAMES F. KEMP : NEW YORK, N. Y. (Term expires February, 1913.) VICE-PRESIDENTS OF THE COUNCIL. S. B. CHRISTY BERKELEY, CAL. W. A. LATHROP PHILADELPHIA, PA. GARDNER F. WILLIAMS WASHINGTON, D. C. (Term expires February, 1913.) KARL EILERS NEW YORK, N. Y. WALDEMAR LINDGREN WASHINGTON, D. C. BENJAMIN B. THAYER NEW YORK, N. Y. (Term expires February, 1914.)

Apr 1, 1912

By A. L., Bailey

All who are even generally aware of the tremendous rate of increase in coal washing operations must realize the growing importance of the float-and-sink test. I believe it is conservative to estimate that, in the past decade, the dollar volume of float-and-sink testing has increased tenfold. It is a simple matter of economy, then, to examine the factors that determine the cost of adequate float-and-sink testing. When the Coal Preparation Section of the Bureau of Mines entered upon a greatly expanded program of such work in connection with the synthetic liquid fuels investigations, it seemed advisable to examine these factors experimentally. The principal consideration that differentiates float-and-sink test sampling from general purpose sampling, is that the original particle size must be preserved. Therefore, the total cost of the test will be directly affected by any standard that might be proposed to limit sample bulk reduction at any given particle size. For this reason, the relationship of sample size to variability of results was the first factor to be studied experimentally.

Jan 1, 1949

By G. Derge, Ling Yang, G. M. Pound

The specific conductance and its temperature dependence were measured over the entire composition range of the molten Cu2S-CuCI system. At a typical temperature of 1200°C, 10 rnol pet of the ionically conducting CuCl reduced the specific conductance from about 77 ohm-lcm-l for pure Cu2S to about 32 ohm -1cm -1, and 50 mol pet CuCl reduced the conductance to that for pure CuCI—about 5 ohm 1cm1. The nature of electrical conduction in molten Cu2S, FeS, CuCI, and mixtures was studied by measuring the current efficiency of electrolysis at about 1100°C. The Cu2S, FeS, and mattes were found to conduct exclusively by electrons, but addition of 1 5 wt pet CUS to Cu2S produces a small amount of electrolysis. Addition of CuCl to Cu2S suppresses electronic conduction, and ionic conduction reaches almost 100 pet at a CuCl concentration of about 50 mol pet. These facts are interpreted in terms of electron energy level diagrams by analogy to the situation in solids. RESULTS of electrical conductivity studies on molten Cu-FeS mattes as a function of composition and temperature have been reported.' The specific conductances ranged from about 100 ohm-' cm-' for pure Cu2S to 1500 ohm-' cm-1 for pure FeS. This is in sharp contrast with the low specific conductance of molten ionic salts for which the transfer of electricity is by migration of ions in the field. In general, these ionically conducting molten salts, such as NaC1, KC1, CuC1, etc., have a specific conductance of the order of magnitude of 5 ohm-' cm-'. It was concluded on the basis of this evidence that molten FeS and Cu,S exhibit electronic conduction. Pure molten FeS has a small negative temperature coefficient of specific conductance, resembling metallic conduction, while pure molten Cu2S has a small positive temperature coefficient, resembling semi-conduction. The molten Cu2S-FeS mattes follow a roughly additive rule of mixtures, both with respect to specific conductance and temperature coefficient. Savelsberg2 has studied the electrolysis of molten Cu2S and Cu2S + FeS. He concluded that while molten Cu2S is an electronic conductor, there is some ionic conduction in molten Cu2S + FeS3 owing to the formation of the molecular compound 2Cu2S.FeS and its dissociation into Cu1 and FeS2-1 ions. The present work does not verify his results. Chipman, Inouye, and Tomlinson" have studied the specific conductance of molten FeO and report a high specific conductance, about 200 ohm-1 cm-1 of the same order of magnitude as that found for molten mattes, and a positive temperature coefficient. They interpret these results in terms of p-type semiconduction in the ionic liquid by analogy to the situation in solid FeO.1 imnad and Derne' detected appreciable ionization in molten FeO by means of electrolytic cell efficiency measurements. In order to verify the conclusion that electrical conduction in molten Cu2S and mattes is electronic, and to gain further insight into the structure of molten sulfides, the following investigations were carried out in the present work: 1) The specific conductance, s of the molten system Cu2S-CuC1 was measured as a function of temperature over the entire composition range. As discussed later, molten CuCl is an ionic substance. It was thought that if molten Cu2S were simply ionic in nature, addition of small amounts of CuCl might not have a catastrophic effect in lowering the high conductance of the Cu2S. On the other hand, if much electronic conduction occurs, addition of the ionic CuCl should have a large effect in destroying the electronic conduction. 2) The electrolytic cell efficiency of the following molten systems was measured at about 1100°C in specially designed cells: Cu3; Cu2S + FeS, 50:50 by wt; FeS; Cu2S + CuS, 15 wt pet; Cu2S + CuC1, 5.9 to 46.4 mol pet; and CuC1. This gives a direct measure of the fraction of current carried by ions in these melts. Further, the cell efficiency, extrapolated to zero ionic current, is given by cell efficiency = (s leasile + s elexstronic). [1] s lucile for molten CulS would be expected to be no greater than that for molten CuC1, whose s lonle is about 5 ohm-' cm-1, as will be seen in the following. u,.,,.,.,.......for molten Cu,S is of the order of 100 ohm-' cm-'.' Thus, a large increase in cell efficiency from 0 to values of 10 to 100 pet upon addition of CuCl to Cu2S would indicate destruction of the electronic conductance. Conductance Measurements Experimental Procedure—The apparatus and experimental method were the same as those described in detail in connection with the study of electrical conduction in molten Cu,S-FeS mattes.' A four terminal conductivity cell and an ac poten-

Jan 1, 1957

By C. R. Johnson, R. A. Greenkorn, E. G. Woods

A new method of reservoir evaluation called pulse-testins has been developed for describing formation properties between wells. Pulse-testing utilizes a sensitive differential-pressure gauge at a responding well to measure and record the response generated by a series of flow rate changes (pulses) at an adjacent or pulsing well. Since the pulse-test instruments have a sensitivity of about 0.001 psi, pulses of several hours or less in duration will generate a measurable response in most reservoirs. For this reason, many well pairs can be tested in a short period of time with little interference in field operations. Comparison of pulse-test results to conventional testing methods shows that the pulses obey unsteady-state, compressible-flow theory and thus provide a measure of both transmissibility (kh/µ) and storage (Fch). In additian, the method can be used qualitatively to describe communication across faults and between zones, and direction and tnagnitude of fracture trends. INTRODUCTION To obtain maximum usefulness of new reservoir analysis methods as well as to aid the field engineer in understanding local reservoir anomalies, improved methods are needed to describe heterogeneities in specific reservoirs. Optimum well spacing, equipment specifications, well completion design and especially the economics of pressure maintenance and secondary recovery programs depend on the extent and location of the heterogeneities that affect flow behavior in the field. One method for obtaining a measure of areal reservoir heterogeneity is an interference test. In the simplest interference test. constant-rate production or injection is initiated at one well and the effect of this flow is measured as pressure vs time at another well. Thus, during interference tests the flow characteristics of the formation are determined in situ. Despite their obvious usefulness in reservoir delineation. interference tests have not enjoyed frequent usage. Reasons for this have been the weeks or months required in many fields to obtain a pressure response measurable with conventional gauges, and the interruption of routine field operation during the field-wide shut-in normally required during these long times. Also, only average properties of the relatively large volume of the reservoir disturbed during these long times can normally be obtained — variations in properties between individual wells cannot be delineated. To eliminate these drawbacks of conventional tests, a special reservoir description technique called pulse testing' has been developed. Pulse-testing has several advantages that make it more convenient and practical for field use than interference tests. Valid tests are more certain because use of a series of flow disturbances gives rise to a diagnostic pressure response that can more readily be distinguished from unknown trends in reservoir pressure and other "noise." The time required is only a fraction of that for an interference test because a special, high-sensitivity differential pressure gauge can detect a much smaller pressure change. Variations in properties between individual wells can be delineated because of the relatively small volume of the reservoir disturbed during these short times. Finally, wells other than the pulsing and responding wells do not have to be shut in or carefully regulated.

Jan 1, 1967

C. W. GOODALE, Butte, Mont. (member of the committee)- (communication to the Secretary*).-In the discussion of papers presented at the New York meeting of the Institute in February, 1915, and at the Arizona meeting of September, 1916, I referred to the activities of the Bureau of Safety of the Anaconda Copper Mining Co., and I am now submitting a few thoughts by members of the staff of that Bureau. TORGUS H. OAAS, Safety Engineer, Butte, Mont.-The report of the Committee on Safety and Sanitation has described different organizations and methods of promoting safety work. The effectiveness of these methods would aid the beginner in his campaign for safety in choosing the kind of organization and methods best adapted for his field. This can he obtained only by a discussion by those who have long promoted this kind of work, and have met with successful results. As the field is new, the different organizations promoting safety work have not established a common basis of rating for their fatal, serious and slight accidents, so that it is now difficult to get a comparative basis from which to judge the merits of the different systems. C. W. GOODALE.-The U. S. Bureau of Mines adopted, at the beginning, as a basis for its yearly summaries, the number of accidents. per 1,000 men employed, and it is now (quoting from its report for 1915, Technical Paper 168) making the following "classification of injuries:" "Many of the States now have. compensation laws, and in order to conform with their classifications, the bureau's classification of serious and slight injuries for 1915 is on a 14-day (2-week) basis instead of 20 days, as in previous years. The new classification of injuries includes three types, as follows: 1. Fatal 2. Serious (time lost, more than 14 days) (a) Permanent disability Total Partial

Jan 6, 1917

By C. Y. Clayton, Francis B. Foley, Muir L. Frey

DuRing the past year, we have investigated the cause of 88 per cent, of the failures by breakage near the bit end of some 1-in. hollow, hexagon, drill steel used in a metal mine. This breakage in the region of the bit end of the steel was peculiarly interesting because we have been Ied to believe that breakage is most prevalent at the shank end of drill steels near the place where the steel is gripped in the chuck of the machine. Records from the mine showed, also, that the breakage was much more frequent in the short lengths of large gage than in the longer steels; this is shown graphically in Fig. 1. Because the shorter lengths of steels are usually those that have been made from broken pieces of long steels or from steels that have worn down in service, rarely being made from new stock, those who are wont to suspect steel of tiring and crystallizing in its old age through fatigue are quite apt to see in this instance an argument in favor of their idea. As usual, a careful examination of these steels reveals defects of a character hardly to be overlooked in favor of such a cause. The steel in question was rolled with a sand core and was of the usual drill steel composition: Carbon 0.85 per cent., manganese 0.60 per cent., silicon 0.25 per cent., phosphorus 0.02 per cent., and sulfur 0.02 per cent., with the exception that in some specimens there was vanadium, not exceeding 0.20 per cent. The following lengths and gages were used: LenGth, GaGe, LenGth. GaGe, Feet Inches feet Inches Starter 2 % 7 111/16 3 2 % 8 11 4 2 % 9 1 9/16 5 2 10 1 7/16 ________6_____________115/16____________________________

Jan 1, 1924

By David B. Scott

The Mogollon mining district, New Mexico, has received little public attention, although for 15 years it has been the leading silver producer of the state; it is situated in a region remote from the principal lines of travel, and its activities have usually been limited to the operations of two or three companies. The value of the total production of the district in the 44 years of its history has been estimated at $15,000,000. For the years 1904 to 1917, inclusive, the output was: gold, $4,370,000; silver, 10,042,000 oz.; copper, 874,862 lb.; total value, approximately $10,500,000. In 1913 the district contributed 80 per cent. of the total silver production of New Mexico, but in 1917 only 41 per cent., due to serious interruption in the operations of the leading producer. Since 1914 the silver output has diminished one-half, and the present high value of silver is nearly offset by the increase in cost of production. The output of gold has rarely exceeded 35 per cent. of the total for New Mexico. The ratio of silver to gold, by weight, has averaged 46:1 based on the whole output of the district. Location and Topography The town of Mogollon is 75 mi. (121 km.) by a poorly located highway ,. from the nearest railroad terminals, at Silver City and Tyrone. All supplies are transported by motor trucks and teams. The area, sometimes called the Cooney Mining District, lies on the western flank of the Mogollon Mountains, which occupy the western part of Socorro County. The elevations drop steeply on the west to the valley of the San Francisco River, adjacent to the Arizona boundary. The topography is very rugged, the whole area being sharply dissected; deep canyons with steep gradients and rugged walls are characteristic of the whole western slope of the Mogollon Range. The main canyons i run east and west, and usually maintain a flow of water during the entire year. As would be expected in a region of such deep dissection, the mines are generally dry. The mountain ridges between the canyons have altitudes varying from 7000 to 10,000 ft. (2130 to 3050 m.) and drop sharply, on their western face, to the floor of the San Francisco Valley at an elevation of 5000 ft. (1525 m.). Erosion has been rapid, and the

Jan 1, 1920

By Herbert Haas

1. INTRODUCTION COPPER matte is now converted into blister copper at a cost of only $5 per ton of copper, or, based on a 40 per cent. matte, $2 per ton of matte, which is the record of at least one large smelting Works; and it seems hardly likely that a further reduction, large enough to warrant, a change in existing practice, could be made in bessemerizing costs. But the new type of converter here described and the new practice proposed are intended, not so much for the treatment of mattes, as for the extension of, the process to the direct reduction in the copper-converter of pyrite ores

Jan 6, 1914

By Ole Singstad

THE legislatures of New York and New Jersey, determined in 1919 that a vehicular tunnel should be built under the Hudson River. On July 1, 1919, an engineering staff was organized with the late Clifford M. Holland as chief engineer, and this staff was given a number of problems to solve, such as location, size, type of tunnel, method of construction, method of ventilation and cost. After a period of preliminary investigations and studies it was decided to build the tunnel at Canal St., New York, connecting 12th St., Jersey City. This is the center of the heaviest traffic across the Hudson River. It was also decided to build two tunnels-one for west-bound traffic and one for east-bound traffic-the tunnels to be of cast iron, built up of segments and bolted together, each tunnel to have a roadway 20 ft. wide and a clear heat room of 13 ft., 6 in. This is to provide for two lines of vehicles in each direction. The tunnels have an exterior diameter of 29 ft., 6 in. The interior lining is of concrete, the sidewalls tiled with a vitreous white tile and the roadways paved with granite block. The entrances and exits at both ends are separated by two blocks so as to reduce traffic congestion. BASIS OF VENTILATION It was recognized very early that one of the most important problems confronting the engineers was a proper ventilation system. It was estimated that each tunnel as planned would have a traffic capacity of 1900 vehicles per hr. The tunnels are 8500 ft. long between portals, and it was considered that the ventilation should be based on all of these vehicles being operated by gasoline engines. That presented a problem in ventilation unlike any other either in magnitude or character.

Jan 8, 1926

• "This country eventually may have to rely on foreign sources for some metals, not because it does not have them here but because it may have difficulty getting the labor to mine them. Few people realize the extent to which the 'old timers' are still the backlog of the important districts." --Fred Searls, Jr. • A new filter has been developed by Arthur D. Little, Inc., for the ABC which will remove all dust from the air. Submicroscopic asbestos fibers are used as filter media and are claimed to stop all dust and pollen while passing suitable quantities of air. •Out in front public relationswise is the Peabody Coal Co. which has launched a 15-min television news program on WNBQ at 10:30 C.S.T., Tuesday and Thursday nights. Clifton Utley, news commentator, will tell how coal is mined today and indicate, with pictures, the improvement in efficiency and safety which has resulted from today's mechanized operations. •Two hundred coal mining companies are using roof bolts as a means of supporting about 14 million sq ft of roof surface, Edward Thomas of the Bureau of Mines reported. Various types of metal and wooden pins can be used. The method was first used by the St. Joseph Lead Co. over 20 years ago, but is now being studied and adopted widely in metal, nonmetallic, and coal mines. * The first ten technical graduates have reported at Hanford Works in the state of Washington, to begin the newly installed General Electric rotational training program, believed to be the first of its kind at any U.S. atomic energy plant. The program is to provide suitably trained personnel for the nation's atomic energy program. •The need for top-notch scientists and engineers to stimulate mining programs in British colonies is acute. About 60 American experts are being sought for the ECA sponsored program. Positions for mining engineers, geologists, assayers, topographers, and petrologists are open. •Production of primary aluminum for the first quarter of 1950 was 322,4250008 lb which is 6 1/2 million lb more than was produced in the first quarter of 1949. Shipments of aluminum sheet, plate, and strip amounted to 259.772,1571b for the first quarter. •Policy on manganese procurement for the stockpile is being studied by a House Armed Services Subcommittee with the possibility of lowering specifications. The U. S. Bureau of Mines is drafting a bill to encourage domestic production for stockpiling through producer subsidies. 'It will have to be cleared by the Bureau of the Budget and other agencies before going to Congress. •Oil men consider dry holes a necessary evil in their search for oil. Last year 34 out of every 100 wells drilled were dry holes. Yet Texas Technological College is attempting to drill a dry hole on its campus at Lubbock, taking every precaution to make sure it is a "duster" so its petroleum engineering students can play around with experiments without being bothered by any messy crude oil. --Natural Resources Notes. •A portable alertness indicator which signals lethargy in persons doing monotonous jobs has been developed for the Navy's Special Devices Center. A possible application to hoistmen is indicated but broaching the matter to them would be tricky.

Jan 6, 1950

By R. C. FLEMING

G OLD MINING is enjoying a real revival in the West, and a considerable portion of the production is coming from small properties. The large mining companies of the world get most of the publicity, but in the last year the small gold property has often proved a more attractive field for the mining engineer looking for something to do. Old mines have been re- opened, prospects have been more closely examined, and many properties that were out of the running with the high commodity and labor costs of two or three years ago, have recently been making money for their operators. An interesting phase of this activity is the operation of so-called one-man mines. The west is dotted with these small properties, without the resources or reserves to warrant large-scale operation, but which return a living and often something over to one or two men who under- stand mining and simple methods of treatment.

Jan 1, 1932

By M. G. Benz, J. F. Elliott

A new type of solution calorimeter has been constructed to measure heats of mixing, enthalpy increments, and heats of fusion, formation, and reaction at temperatures above 1000°C. With it, measurements hove been made of the partial molar heats of mixing joy tin in the Cu-Sn system from 0 to 13 at. pet Sn at 1127°C and fir nickel in the Cu-Ni system from 0 to 9 at, pet Ni at 1200°C. The integral molar heat of mixing for the Cu-Sn system is strongly negative with a calculated minimum value corresponding to the composition Cu3Sn. The integrnl molar heat of mixing for the Czi-Ni system is slightly positive at these temperatures. These integral molar values have been measured with a probable error less than 30 cal per g-atom at an atom fraction of nickel or tin equal to 0.1. The estimated probable error for the Cu-Sn system is approximately 450 cal for a measured heat of solution of approximately 9000 cal. For the Cu-Ni system it is approximately 700 cal for a measured heat of' solution of approximately 60 cal. A new type of heat of solution calorimeter was designed and constructed to provide a more accurate experimental method for determining heat effects at high temperatures, (T > 1000°C). With it, partial molar heats of mixing, enthalpy increments, heats of fusion, and heats of formation and reaction for metal systems can be measured directly. Previously it has been necessary to rely upon the use of the dropping calorimeter or the van't Hoff equation applied to equilibrium data for this information. For the most part equilibrium data are scarce and difficult to obtain in many cases, and it has been necessary to rely upon the "method of mixtures" for the desired enthalpy measurements. An earlier study1 provides a prototype for this work. The "method of mixtures" as outlined by K. K. kelley,2 "consists of dropping the substance under investigation from a furnace, with controlled and measured temperature, into a calorimeter operating at or near room temperature.'' In this manner the change in the total heat content (enthalpy) of the substance between the temperature of the furnace and that of the calorimeter is determined. In order to determine high-temperature heats of mixing, enthalpy increments, and heats of fusion, formation, and reaction, it is necessary to take the difference between two such measurements, one before and one after the occurrence of the enthalpy change being studied. The desired enthalpy change is then the small difference between two large numbers. Small errors in the large numbers are included as large errors in this small difference. It is this difficulty that must be avoided for accurate measurement of the desired functions. The procedure with the new solution calorimeter consists of dropping the substance under investigation from a furnace, with controlled and measured temperature, into a solution calorimeter operating in the temperature range of 1000o to 1200°C. Measurements in the range of 1200" to 1600°C are planned for the future. By selection of the composition and

Jan 1, 1964

By Walter C. Lawson

The primary objective in laying track in panel sections is to reduce the number of track laborers required. This is possible because the work is mechanized. Moreover, because the work is mechanized and each of the operations needs only a few men, and each is self-contained, the work can be carried on at night as well as in daylight; therefore, the method provides a means of preparing tracks on more than one shift. The laying of tracks in open pits and quarries in panel sections is not new but new methods have been made possible by the introduction of new types of equipment. The purpose of this paper is to describe the methods that are followed in the Morenci open pit. General Mining Operations Full-scale ore production at Morenci is about 50,000 tons daily. The normal yearly output of ore and waste is 32,000,000 tons, of which 30,000,000 tons is handled by rail haulage. This requires the building of approximately 47 miles of loading and other temporary tracks during a 12 months' period (Fig I). Broken ore and waste is loaded into 90-ton capacity dump cars with 5-cu-yd full-revolving electric shovels. Shovel banks are uniformly 50 ft high. They are blasted with churn drill holes and the broken material from a blast is loaded out with two shovel cuts, the first one being called (locally) the "splatter" cut and the second one the "clean-up" or "face-up" cut. When a shovel is making its clean-up cut, the loading track is about 70 ft from the toe of the bank and, under normal conditions, a bank is blasted against it without removing the track. It is thus evident that each track is used for two shovel cuts before relocation is necessary, inasmuch as a single position serves for both the clean-up cut prior to blasting and for the splatter cut following the blast. The normal advance of a solid bench by a single blast is 40 ft (Fig 2). Preparation OF Panel Grade In preparation of panel grades bulldozers and rooters are used for the bulk of the work and an auto-patrol road grader for the final stage. At Morenci, bulldozers have always been used for track-grade preparation, but before the introduction of the other two types of equipment grades were uneven and irregular at best, and always necessitated a big gang of track laborers to hand-block under the ties with rocks after a track was laid into place. High blocking also made poor track because of instability and caused frequent derailments. Under these conditions derailments were generally bad as re-railing became difficult. Much track was torn up and many tics broken in the process. The inadequacy of the hand-blocked track, together with the inefficiency of hand blocking, constantly pointed, to the desirability of reducing the amount of labor required, so various means were tried to improve conditions, such as wood

Jan 1, 1949