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By C. D. Woodward

The Anaconda Copper Mining Co. purchases 25,000 kw. of electric power for its mining operations at Butte, Mont. This power is delivered, over duplicate feeders, in the form of 60-cycle, 2400-volt, three-phase current, to five compressor plants, where most of the energy is used for driving air compressors. At the compressor plants are located the switching apparatus for controlling the 2400-volt power and distributing it to the various mines. At these points, also, there are a number of motor-generator sets for converting the alternating current to 275-volt direct current for the haulage systems. Pole lines convey the powcr from the compressor plants to outdoor transformer substations at most of the mines. When it is not economical to distribute the power at the lower voltages in the mines, transformers and motor-generator sets are placed at strategic points underground. All power is purchased on a maximum-demand basis; therefore there is installed at one of the compressor plants an eight-element totalizing graphic wattmeter. This instrument records simultaneously the value of all power taken at the numerous points of delivery, which not only climinates the diversity factor but permits load dispatching between compressor and pumping plants, and thus materially reduces the maximum demand from the power system. As most of the mine hoisting is done by 90-lb. compressed-air winding engines, the air-compressor equipment for the winding engines and mining operations is quite extensive. The standard air compressor has a rating of 7500 cu. ft. per min. of free air, and most of the compressors are directly connected to synchronous motors. The synchronous motors are designed for 80 per cent. loading power factor, thus facilitating power-factor correction of total mine load. Consequently by cooperation with the power company, the voltage of the power received at the compressor plants is constant. In the mines there are installed an induction motor load of approxi-mately 10,000 hp., and 4500 kv.-a,, in transformer capacity. It is the practice to install 2200-volt motors in the mincs, except those rated below 50 hp, hence there are in operation underground about 5000 hp., in the

Jan 1, 1923

By W. A. Barrows, Carl Zapffe

Jan 1, 1913

By P. A. E. Armstrong

For hardening, the steel should be heated just above the critical temperature, as a properly forged steel quenched from this heat has some toughness, with maximum hardness and density. The quenching bath should be kept at approximately a constant temperature. In drawing or tempering, longer time periods at lower temperatures are better than the shorter periods at higher temperatures. A recent questionnaire brought out the following facts: The double-arc, double-taper bit and cross bit give the best service; resharpening of the drill steels most frequently was caused by wear of gage; chipping of bit was, with one exception, the second cause; breakage of shank was with one exception, the third cause; upsetting of bit, upsetting of shank, and breakage of body were the fourth cause. The direct cause of the necessity of resharpening given was poor heat treatment first, and faulty steel and severe rock conditions second. Rock-drill Steel By N. B. Hoffman Much of the drill steel produced in America is manufactured into hollow rods. After all forging has been finished the entire bar should be thoroughly annealed and heat trcated before the point is hardened and tempered, at least where the drill has heavy duty, such as working in deep holes and hard rock. A large number of tools of like character and doing work requiring similar properties are now being made of alloy steels; for instance a steel with a carbon content of 0.75 to 0.85 per cent., manganese 0.25 to 0.35, phosphorus under 0.020, sulfur under 0.030 and vanadium 0.18 to 0.23 has proved very satisfactory for chisels. A steel of this type properly manufactured will be far superior to the ordinary carbon steels, while at the same time is one whose price range should not prove prohibitive. Much of the cutting efficiency of a drill depends on proper heat treatment. This vanadium steel has a far greater safe hardening and forging range than ordinary carbon steels, making it more nearly foolproof. It will harden nicely at 1400" I?. but will also harden well and satisfactorily at 1550" F. retaining its quality of hardness and toughness in either case. Drill Steel from Hollow Ingots BY P. A. E. ARmstrong Hollow drill steel is made from a drilled billet with a sand-filled core or the drilled, pierced, or the drilled and pierced billet, not sand-filled, is rolled down over a projectile or ball much the same as in ordinary pipe manufacture. The first is the method generally used in this country; the second is used largely in Sweden. Swedish hollow drill steel has a

Jan 1, 1922

By B. A. Eaton, K. E. Brown, C. R. Knowles, D. E. Andrews, I. H. Silberberg

This paper presents the resitlts of an investigation of two-phase, gm-liquid flow in horizontal pipelines. Experimental data were taken in three field-size, horizontal pipelines, two of which were constructed for this purpose. The data were obtained using water, distillate and crude oil separately as the liquid phase, and natural gas as the second phase. Experimental pressure-length traverse, liquid holdup and flow-pattern data were collected for each set of flow rates. These data were used to develop three correlations that are presented herein. The liquid-holdup values correlated with various flow parameters without regard to the existing flow pattern. The same was true for the energy-loss factors. A new flow-pattern map is presented that appears to be quite reliable, but not required for the pressure-loss calculations. The liquid-holdup correlation and the energy-loss factor correlation are used in conjunction with a two-phase flow power balance, developed during this study, to predict the pressure losses that occur during gas-liquid flow in horizontal pipelines. A recommended calculational procedure is given, as well as a statistical analysis of the results. This procedure lends itself to computer application, since several small pressure decrements are needed to calculate a pressure-length traverse. The correlations are shown graphically, but may be curve fitted with existing curve-fitring computer programs. INTRODUCTION Due to the frequent occurrence of gas-liquid flow in pipelines and the desire to accurately calculate the pressure losses that occur in these lines, two-phase flow is of considerable interest to the petroleum, chemical and nuclear industries. In the petroleum industry, gas-liquid mixtures have been transported over relatively long distances in a common line due to the advent of centralized gathering and separation systems. Long two-phase flowlines are usually accompanied by large pressure drops which influence the design of the system. Gas-lift installations are designed on the basis of known tubing pressures at the wellheads. The horizontal flowline connecting the wellhead and the separator system must be correctly sized in order to minimize the horizontal flowline pressure losses and the wellhead tubing pressure. Practically all oilwell production design involves horizontal two-phase flow in pipeknes. All of the flow processes of oil and gas production must be studied simultaneously to insure good well design. Since the beginning of offshore oilfield development, long horizontal flowlines have been constructed. Because pressure losses greatly influence the performance of producing wells, a method is desired that can be used to predict such pressure losses and select optimum flowline size. Several types of gas-liquid flow exist, and many of these are discussed by Gouse The study of pressure gradients, fluid distributions and flow patterns that occur in horizontaI multiphase flow is made difficult by the great number of variables involved. The various flow regimes give rise to changing velocities of the fluid particles in all directions. These instabilities of the interface between the gas and liquid prohibit the determination of actual vector velocities of fluid particles in each phase. Also, it is practically impossible to arrive at correct sets of boundary conditions. Therefore, most investigators have concluded that a solution to the problem by the classical fluid dynamics approach, whereby the Navier-Stokes equationsM are formulated and solved, is far too complex. Other methods must be utilized to develop general correlations that will predict the behavior of gas-liquid horizontal flow systems. Multiphase flow studies have sought to develop a technique with which the pressure drop can be calculated. Pressure losses in two-phase, gas-liquid flow are quite different from those encountered in single-phase flow; in most cases an interface exists and the gas slips past the liquid. The interface may be smooth or have varying degrees of roughness, depending on the flow pattern. Therefore, a transfer of energy from the gaseous phase to the liquid phase may take place while energy is lost from the system through the wetting phase at the pipe wall. Such an energy transfer may be either in the form of heat exchange or of acceleration. Since each phase must flow through a smaller area than if it flowed alone, amazingly high pressure losses occur when compared to single-phase flow. Most investigators of horizontal two-phase flow phenomena have chosen to separate their experimental data into several groups of observed flow patterns or regimes.

By G. R. Belton, Y. K. Rao

A galvanic cell, using liquid MgCl2 or MgC12-CaC12 mixtures as the electrolyte, has been used to determine activities in Mg-A1 liquid alloys between 700' and 880°C. The incovporation of a chlorine electrode in the cell also allowed measurements to be made of the standard free energy of formation of MgCl2(l). The results are shown to be in good agreement with thermo-chetrlical values from the literature, and this is taken as evidence that the small, known solubility of magnesium in iMgCl2 introduces no significant error in galcanic cell measurements. Within experimental error, the activity coefficients and relative partial molar enthalpies at 800°C are shown to be represented by the following "subregular" solution equations: logy~~ =-0.68(1 -xMgj3 log yAL =-1.02(1 - XMf + 0.68(1 - XMf H.M = -4400(1 - %)3 / cal Mg 7Ag' HZ =-6600(1 - xA1)' + 4400(1 - XMf cal SCHNEIDER and toll' have used a transpiration technique to measure the vapor pressures of magnesium over Mg-A1 alloys between 544" and 594°C. amsstad,' however, has since suggested that the extrapolation to zero flow rate, used by these authors in interpreting their apparent pressure vs flow rate data, gives unreliable results. Rogers, Tomlinson, and Richardson,3 in interpreting the results of solution equilibria between Mg-A1 alloys and liquid MgC12, also considered the measurements of Schneider and Stoll to be unreliable and preferred to derive activities for the alloys from the earlier boiling point determinations of ~eit~ebel~ and the partial molar heats recommended by Kubaschewski and ~atterall.~ These latter heats were based substantially on the early calorimetric work of Kawa-kami but, unfortunately, his work on other systems has sometimes been found to be inaccurate.7 Rogers et al., in the above-mentioned paper,3 tentatively concluded that the most likely species responsible for the limited solubility (0.3 mole pct at 800°C) of magnesium in MgC12 were Mg° (neutral) and Mg2++. Two more recent studies8,9 have supported Mg2++ as the soluble species. In the present study, activities in Mg-A1 alloys have been determined by means of a galvanic cell involving liquid MgCl2 or MgC12CaCl, mixtures as the electrolyte. Since the reactive nature of magnesium precluded simple Faraday yield experiments, a chlorine electrode was incorporated in the cell in order that the performance of the cell could be checked by measurements of the heat and free energy of formation of MgC12. This procedure was considered necessary since it has been suggested1' that the solubility of a metal in a molten salt might introduce electronic conductivity; also, previous determinations of the standard electrode potential for MgC12 differed by as much as 70 mv11-13 EXPERIMENTAL Materials. Analyses of the materials used in preparing the alloys and the electrolyte mixtures are presented in Table I. The alloys were prepared by induction melting weighed amounts of the metals in a graphite crucible held under an argon atmosphere. Pure anhydrous magnesium chloride was prepared by heating the mixture MgCl, . 6H20 +NH4C1(1:1) to 650°C, followed by melting under dry argon. The melting point of the dry MgC12 was found by differential thermal analysis to be 714.8oC, which compares well with the accepted value of 714C.14 This agreement was taken to be an indication of the high purity of the dried salt. Table I. Compositions of Materials, wt pn Impurity Mg Al MgCI2 CaCI, Ba - - 0.005 Ca - - 0.010 Cu 0.02 0.02 Fe - 0.10 0.001 0.010 Pb 0.01 - 0.001 0.005 Mn 0.15 0.001 Si - 0.10 Sr - - 0.005 MBSO* - 0.040 ARGON TUNGSTEN CHLORINE LEAD—411 11 II ALUMINA 'A I / ave GRAPHITE on irA~_ ( ^"l ROD MAGNESIUM S>ILICA~^ /, OR ALLOY-. I /A] ___________ -«^- _ ELECTROLYTE I y FRITTED DISCS Fig. l—Arrangement of chlorine and metal electrodes in electrolytic cell.

Jan 1, 1970

By AIME AIME

I N JUNE, 1918, at a meeting of the American Society of Mechanical Engineers in Worcester, Mass;, a resolution was adopted for a committee to investigate the aims and organization of that society. This was followed subsequently by similar independent action on the part of the Society of Civil Engineers. The other two Founder Societies were approached and requested to appoint similar committees, the four committees to combine as a .Joint Development Committee, later called the Joint Conference Committee, to investigate what might be done in the way of coordinating those activities of the Founder Societies which ape of common interest, and which were then being pursued separately. The Joint Conference committee worked diligently -for almost. two years and. brought forth a tentative as outlined in its report which was published in full in MINING AND. METALLURGY, December, 1919. It recommended the formation of a nation-wide organization to be composed of representatives' of all of -the engineering societies, local, state, regional, or national, the object to be to further the interest of the public through the use of technical knowledge and engineering experience, and to consider and act upon matters common to the engineering and allied technical professions. Whereas the technical societies have large fields of endeavor in welfare work, and their prime. efforts are 'still in technical lines, this new organization was to be devoted entirely to service, looking to the welfare of the nation and the engineering profession, and to service for the public in local and state affairs.

Jan 1, 1920

By V. Kondic, W. M. Rumball

HUNT and Jackson' have recently suggested that binary eutectics might be classified according to the entropy of fusion of the component phases. Such a classification was in fact proposed2 some time ago by the authors and the purpose of this communication is to present some supporting evidence. As pointed out by Hunt and Jackson' typical metals of low entropy of fusion, ?S, tend to form normal eutectics (using Scheil's terminology3). Where one phase is metallic (low ?S) and the other nonmetallic (high AS) then anomalous structures are formed. These anomalous structures may either be regular (e.g., Bi-Sn)or irregular (e.g., A1-Si). Finally Hunt and Jackson suggest that where both phases are of high ?S regular faceted structures are formed. In the proposed classification2 the ratio of the entropies of fusion is taken as the quantitative parameter, i.e., ?Sa/?SB = E, where e > 1.0. An extensive literature survey has been carried out2,4 for reliable photomicrographs of eutectic structures. The structures, numbering 151, have been classified into two classes, viz., normal (i.e., lamellar and rodlike) and anomalous. The latter group has been arbitrarily subdivided into regular and irregular anomalous eutectics. Details and sources of the structures are given elsewhere.2,4 In the absence of better thermodynamic data the value of E has been determined for each of the systems making the following assumptions and approximations: l) The entropy of fusion of solid solutions may be calculated additively;5 ii) Inter metallic compounds are treated similarly but with the addition of the following term for fully ordered structures.5 -4.573(Ni lOg10 Nl + N2 log10 N2) where Nl and N2 are the atomic fractions. It might be argued that the entropies of fusion are meaningless as the eutectic phases form at some temperature (T,°K) below their true melting point (Ta or Tb). As AS, = Lo/To if La the latent heat of fusion of a, is assumed independent of temperature, the actual entropy change AS& is given by La/Te. The ratio of entropies of fusion then becomes Fig. 1 shows E' plotted against cumulative totals for normal and anomalous systems from which it is seen that normal eutectics predominate at low values of E'; e.g., some 90 pct of normal systems lie below E' = 1.5 with 65 pct of anomalous systems above this value. Fig. 1 also shows that the regular anomalous structures occur mostly at low values of c' possibly suggesting growth more akin to normal than anomalous growth. The choice of c as a classification parameter was based on nucleation concepts, it being observed that metals widely separated in Sundquist and Mondolfo's8 nucleation series were anomalous and those close together normal. The basis of these classification views is really outside the intended scope of this communication but it is hoped to explain them fully in the near future.7 Having arrived at this entropy of fusion classification by nucleation considerations it is interesting to note that Hunt and Jackson's ideas are based on growth considerations. Elsewhere one of the authors4 has shown that an even better classification of the metallographic structures reviewed is obtained from purely conventional heterogeneous nucleation concepts. It has been found that systems having a value of the parameter +b less than 0.28 are almost certainly normal and above this anomalous: V, is the gram atomic volume. This parameter is nevertheless closely related to c and c', these being an approximation of p. The parameter is also related to the other classification3,8,9 which have met with any success in the past. All these classifications are to be reviewed shortly by the authorsU7 A significant thing about the classifications based on

Jan 1, 1968

By P. Davey Wheeler

San Francisco meeting, September, 1915) IN an article in the General Electric Review, January, 1915, reference was made to the X-ray examination of a steel casting 9/16 in. thick. Fig. 1 shows one of the radiographs thus obtained. All these radiographs showed plainly the tool marks on the surface of the casting. All but one showed peculiar markings the shape of which strongly suggested that they were indeed the pictures of holes in the interior. A circular piece, 1 in. in diameter, was punched from the casting at a point where the radiograph shown in Fig. 1 indicated that a blow-hole should be found. (Location of sample shown by circle in Fig. 1.) Fig. 2 is a photograph of the end of the punching, showing the .hole that was found. Since that article was written it has seemed desirable: (1) to obtain data from which the exposure necessary for any thickness of steel could be at once calculated; (2) to find the thickness of the smallest air inclusion which could be radiographed in a given thickness of steel; (3) to determine in what direction to hope for further progress; and (4) to develop the technique of, radiographing metals. In order to gain some preliminary data, several pieces of ½ -in(12.5mm.) boiler plate were obtained, 5 by 7 in. (12.5 by 17.5 cm.) in size. In one of these, holes were drilled in such a way that the axis of each hole was midway between the faces of the steel and parallel to those faces. The diameters of these holes were as follows: Hole number Diameter 1 1/4 in. = 6.3 mm 2 1/8 in. = 3.1 mm. 3 1/16 in. = 1.6 mm. 4 1/32 in. = 0.8 mm. 5 1/64 in. = 0.4 mm.

Jan 8, 1915

By Roger C. Malan

The Monument Valley and White Canyon districts are in northeastern Arizona and southeastern Utah. Exploration and mining for uranium has been conducted in these districts since the late 1940's. In July 1965, ore reserves plus ore production at 174 properties were approximately 3.3 million tons of ore containing about 19 million pounds U3O8, of which about 10 per cent remained in reserves. The two largest mines, Monument No. 2 and Happy Jack, together account for about 45 per cent of the sum of production and reserves. Approximately half the deposits in these districts contain less than 1000 tons of ore. Nearly 5000 feet of Permian, Triassic, and Jurassic sedimentary rocks, mainly continental in origin, are exposed in these districts. All the important uranium deposits are in the Shinarump, the basal member of the Chinle Formation of Triassic age. The Shinarump lies on a widespread unconformity. It is composed of fluvial sediments, generally less than 100 feet thick, that were deposited by streams flowing from a source to the south. Most of the deposits are in an arcuate belt, convex to the west. This belt, 3 to 12 miles wide, extends from Monument Valley northward nearly 130 miles. It is along the western flank of the ancient Monument Valley-Monticello upland, an area that was slightly uplifted at the beginning and again at the end of deposition of the Shinarump. Erosion and subsequent reworking of the Shinarump sediments in the vicinity of this upland are postulated to have made possible the transportation, in solution, of the uranium contained in these sediments. The soluble uranium probably was carried by migrating ground water into sites favorable for precipitation in Shinarump beds bordering the upland. Thus, the original very small amounts of dispersed uranium in the early Shinarump sediments were accreted in the favorable belt where the accumulations of carbonaceous plant remains and their decay products provided a persistent reducing environment.

Jan 1, 1968

By Eugene McAuliffe

NO physical impairment can be more serious than the partial or complete loss of sight. With reasonably good eyesight, a person is equipped to care for life and I limb, provided a rational measure of t caution is manifested. When the sight of one eye is lost or badly impaired, one-half of this God-given asset is gone, and extreme care must be taken to prevent the tragedy of total darkness that closes out the beauty of sky, field and mountain, the faces of relatives and friends, and either removes entirely or in part one's capacity to produce and earn. During 1933, The Union Pacific Coal Co., operating ten coal mines in Wyoming, decided to undertake a visual survey of all of its mine operating officials and employees. Although the cost of workmen's compensation paid because of eye injuries was material, the management was more deeply concerned with the social loss and the suffering resulting from the many eye injuries. As every element of coal production cost must be scrutinized, accurate data on all accidents, with the workmen's compensation paid therefor, are carried forward monthly. The number of accidents to eyesight and the resultant compensation paid are shown in Table 1 for nine calendar years:

Jan 1, 1934

By R. W. M. Lai

This paper presents a simple flotation kinetics model (Lai, 1981) along with a method of presenting the model in an informative graphical form. Examples are given for evaluating various flotation conditions and different ore types.

Jan 1, 1983

By T. B. Counselman, T. B.

Continuous countercurrent decantation calculations have always been a headache to the cyanide man (and the chemical engineer) because of the simultaneous equations involved. These are tedious to solve, and there is considerable opportunity for mathematical error. This paper presents a shortcut method for making these calculations, which has been in successful use for twenty years by the author, and which is particularly valuable in selecting the best of several possible flowsheets, or evaluating the effect of various assumptions.

Jan 1, 1950

By Persifor Frazer

It has been the aim of the writer, by measuring his base line on the territory of theoretical chemistry, to attempt to fix by triangula tion certain points within the domain of mineralogy. As the barest first experiment in this direction, a few of the hydrated oxides of iron have been selected, their theoretical construe tion reduced to percentage of the constituents into which the ordinary analytical methods would resolve them, and the results compared with actual analyses compiled from the most reliable sources; the accidental errors being as much as possible eliminated. This method seems to be a simple one and one easily pursued, but, as will shortly appear, it is beset with grave difficulties, all of which the writer does not pretend to have satisfactorily surmounted. In the first place arises the important question, what are we to understand by the hydrated oxides of iron ? In all books of chemistry and lexicons of minerals, the proposition, long ago taught by the earlier chemists, that water might exist in two forms of combination, viz., as water of crystallization or as water of constitution, is tacitly assumed. There is nothing in the principles of the new chemistry which is opposed to this; for (to carry the mind's eye into the process of con struction of the least units into which a definite chemical compound is capable of being divided without losing its characteristic proper ties), however unlikely it may seem, it is, nevertheless, possible that a given molecule of iron may, under certain conditions of heat, pressure, etc., attract to itself as many molecules of the water in which it is natant as: from the relative size, shape, attractive force, etc. of either, it is capable of taking up, and this complex system of associated molecules might oscillate as a physical unit so long as the conditions on which its existence was dependent remained unchanged. Moreover, it is highly probable that the first effect upon such a mole cule produced by physical or chemical forces would be to separate it into two or more simple ones of different kinds, while a further ap plication of these forces might rend asunder the bonds of the simpler compounds themselves.

Jan 1, 1879

By Persifor Frazer

(Read at the Amenia Meeting, October, 1877.) IT has been the aim of the writer, by measuring his base line on the territory of theoretical chemistry, to attempt to fix by triangulation certain points within the domain of mineralogy. As the barest first experiment in this direction, a few of the hydrated oxides of iron have been selected, their theoretical construction reduced to percentage of the constituents into which the ordinary analytical methods would resolve them, and the results compared with actual analyses compiled from the most reliable sources; the accidental errors being as much as possible eliminated. This method seems to be a simple one and one easily pursued, but, as will shortly appear, it is beset with grave difficulties, all of which the writer does not pretend to have satisfactorily surmounted. In the first place arises the important question, what are we to understand by the hydrated oxides of iron ? In all books of chemistry and lexicons of minerals, the proposition, long ago taught by the earlier chemists, that water might exist in two forms of combination, viz., as water of crystallization or as water of constitution, is tacitly assumed. There is nothing in the principles of the new chemistry which is opposed to this ; for (to carry the mind's eye into .the process of construction of the least units into which a definite chemical compound is capable of being divided without losing its characteristic properties), however unlikely it may seem, it is, nevertheless, possible that a given molecule of iron may, under certain conditions of heat, pressure, etc., attract to itself as many molecules of the water in which it is natant as from the relative size, shape, attractive force, etc. of either, it is capable of taking up, and this complex system of associated molecules might oscillate as a physical unit so long as the conditions on which its existence was dependent remained unchanged. Moreover, it is highly probable that the first effect upon such a molecule produced by physical or chemical forces would be to separate it into two or more simple ones of different kinds, while a further application of these forces might rend asunder the bonds of the simpler compounds themselves.

Jan 1, 1878

By D. S. Choi, R. Stefanko

There are a number of complex factors that influence the effectiveness of anchorage to maintain tension in rock bolts. However, a plastic analysis of the anchorage site employing certain simplifying assumptions with application of the Mohr-Coulomb criterion appears to explain the observed phenomena. Such an analysis has been made and a correlation sought with field and laboratory tests. Field tests were made in an anthracite mine in eastern Pennsylvania and included pull tests and long-term tests of a variety of anchorage devices in two basic lengths, 30 and 42 in. in two widely differing seams. Performance is reviewed for wedge, expansion shell, and resin anchorage. Laboratory tests duplicated many of the field conditions but in addition compared the performance of shells with normal and reversed serrations. This performance was compared with the predicted results from the plastic analysis. One of the major problems in conducting long-term underground tests is the selection of suitable instrumentation. All installed bolts were fitted with spherical and hardened washers to insure the best possible torque wrench readings. In addition, commercially available load cells were used. Finally, the performance of a specially developed strain-gage-equipped ring cell is viewed. Rock bolting as a method of support continues to increase with applications in many other industries in addition to mining. Nevertheless, with nearly 55,000,000 roof bolts installed in coal mines alone last year, this remains as the single greatest use. While bolts have frequently supported ground where conventional timbering could not, there are relatively few design criteria; and trial-and-error procedures prevail. Furthermore, there has been a lag in development of suitable instrumentation that is simple to install and read out, sensitive, durable, reliable, safe, and economical in evaluating the effectiveness of a bolt over long periods of time. Therefore, the pull test continues to be the most popular method of evaluating the applicability of a certain type of roof bolt under specific installation conditions. At The Pennsylvania State University in the Dept. of Mining, research has been conducted for a number of years to measure bleed off in carefully controlled laboratory experiments as well as in underground investigations."-' Unfortunately, most of the instrumentation developed has been primarily suitable only for research purposes, not possessing all of the aforementioned characteristics desirable for routine underground use. Other groups also have met with restricted success. Therefore, while relatively crude, the torque wrench continues to remain as the most widely used load measuring device. While both field and laboratory tests continue to be con- ducted, analytical analyses are attempted to discover the more important design parameters in order that more efficient anchorage might be devised. Bolts are being used for a greater variety of purposes in mining. Suspending wire sideframe belt conveyors from roof bolts is a common application. The suspension of a monorail transportation system presents yet another. One such system has just been installed in a recently reopened anthracite mine and is presently being evaluated under production conditions. Preliminary studies revealed that a considerable cost reduction was possible by suspending the monorail on bolts anchored in the top. The monorail was to be installed under two widely differing conditions—a competent sandstone above the Buck Mountain seam and a softer shale top above the Skidmore. The type of anchorage device, length of bolt, and long-term performance, consistent with economy and safety, had to be established for the installation once the decision was made to suspend the system on rock bolts. This paper describes some of the testing procedures leading to a final selection. Theoretical Analysis of Expansion Shell Anchorage A detailed look at an expansion shell assembly might shed some light on the factors involved in the design of a suitable shell, Fig. 1. When a bolt is rotated, the tapered plug is forced downward, expanding the leaves laterally to grip the sides of the hole. Two friction surfaces are present: (1) the interface of the plug and leaf and (2) the interface between leaf and rock. The relationships of these friction planes, geometry of expansion shell, and properties of the rock are important in the design of an expansion shell. Therefore, an analysis assuming the rock to behave as a rigid plastic material with its yield governed by the Mohr-Coulomb criterion was made." Furthermore, the effect of friction between the leaf and rock produced by serrations was analyzed.

Jan 1, 1971

(Members are urged to send in for this column any notes of interest concerning themselves or their fellow-members.) Members and guests who called at Institute headquarters during the period May 10, 1916 to June 10, 1916: G. Aertsen, Philadelphia, Pa. Hennen Jennings, Washington, D. C. Frederick C. Alsdorf, Wickenburg, Ariz. H. M. LaFollette, LaFollette, Tenn. A. H. Anderson, Worcester, Mass. E. T. Lednum, Chicago, Ill. J. H. Batcheller, Mattapoisett, Mass. Francis Church Lincoln, Reno, Nev. Arthur B. Clark, Sheridan, Mont. H. Mortimer-Lamb, Montreal, Canada. J. Murray Clark, Toronto, Canada. Andrew W. Newberry, San Francisco, Cal. J. H. Collier, Oakland, Cal. C. E. Pettibone, Cleveland, 0. H. S. Emlaw, Spring Lake, Mich. Heinrich Ries, Ithaca, N. Y. E. L. Estabrook, Platteville, Wis. C. S. Robinson, Youngstown, 0. James W. Hambleton, El Paso, Tex. - M. K. Rodgers, Basin, Mont. James Henderson, London, England. E. J. Rossbach, St. Louis, Mo. G. P. Hulst, East Chicago, Ind. J. B. Tyrrell, Toronto, Canada. William F. Jahn, Riebeling, Mont. G. B. Waterhouse, Buffalo, N. Y.

Jan 7, 1916

By J. L. Stuck

Geological investigation and research have contributed greatly in making industrial minerals the basis of an important industry in the state. North Carolina contains a wide variety of industrial minerals and rock. Mica, feldspar, kaolin, halloysite, talc, pyrophyllite, silli-manite, and spodumene are used to illustrate the progress being made. IN a previous paper1 an attempt was made to indicate the importance of industrial minerals in North Carolina and the wide variety of such materials present. The present paper is concerned with geological investigation and research which have made industrial minerals the basis of an important industry in the state. Geological mapping has gone through three stages in North Carolina during the present century. The first stage is represented by excellent reports of which Corundum and the Peridotites of Western North Carolina,2 Volume I, now a classic, is representative. In this report, a geologic map of the western third of the state is shown on a scale of 10 miles to the inch. The next stage is represented by folios" of the U. S. Geological Survey published between 1902 and 1932. Most of these contained 30 min quadrangle maps on a scale of 2 miles to the inch. The third step is represented by reports prepared during the past 10 years which contain geological maps4 on scales varying from 500 ft to 1 mile to the inch, while many mine maps have been prepared on scales varying from 20 to 150 ft to the inch. As the scale on which geological mapping has been done has decreased, the amount of information secured has increased. Pratt and Lewis did excellent work on the peridotites of western North Carolina, but their maps lacked details. Keith and others added

Jan 1, 1952

By R. W. Cahn, C. D. Graham

The rate of growth of a single grain growing into a strained aluminum single crystal, measured by the conventional heat-cool-etch technique, is shown to decrease with time at temperature. The growth rate measured by means of X-rays, with the sample continuously at temperature, is found to be linear. Evidence is presented to show that the decreasing growth rate obtained by the conventional technique is due to abnormal recovery in the strained grain, and that the recovery in turn results from the heating and cooling cycles, rather than from the effects of etching. The experimental apparatus is described in an appendix. FREQUENTLY, the rate of grain boundary motion during recrystallization is determined by heating a sample to a known temperature for a given time, cooling to room temperature, and etching to reveal the boundary position. The cycle of operations is repeated as many times as necessary to establish the rate of boundary motion. Although this heat-cool-etch technique has been used by a number of workers over a period of many years,'-!' other investigators have encountered difficulty with the method."'. " They have attributed the erratic results to the effects of repeated heating and cooling, or of etching, or both, and have adopted an alternative experimental procedure in which a number of identical samples are employed, each sample being cooled and etched only once. This alternative method ove1.comes some difficulties, but introduces others. In particular, the incubation periods of the observed grains are unknown: any effect of crystal orientation on growth rate cannot be determined easily. A preferable method would be to measure the motion of a recrystallizing grain boundary with the sample at temperature without etching," but such measurements have in the past been restricted to nonmetals. This paper describes the construction and operation of a device, the goniometer furnace, with which the position of a moving grain boundary between a recrystallizing grain and the strained single crystal into which it grows can be measured by means of X-rays, with the sample maintained continuously at temperature. Goniometer Furnace The operating principle of the goniometer furnace is shown in Fig. 1. The sample, in the form of a bicrystal strip, is surrounded by a furnace, not shown in the sketch, and can be rotated about the two axes A and B which intersect at the point where the X-ray beam strikes the strip. The strip is oriented so that one of the two grains gives a strong Bragg reflection, which is detected by a suitably placed Geiger-Miiller counter coupled to a counting-rate meter When the strip is moved parallel to its own length in the furnace, arrow C, so that the X-ray beam strikes the second grain, there is in general no strong reflection. By noting the position of the strip at which the drop in Geiger counter reading occurs, it is possible to determine the position of the boundary. Measuring the change in boundary position with time at temperature gives the rate of growth of the recrystallizing grain. Details of the construction and operation of the goniometer furnace are given in the Appendix. Measurements showed that the temperature in the furnace was uniform within ±10°C over its working length of about 28 cm. The temperature at the measuring position, i.e., at the point where the X-ray beam struck the sample, was estimated to be constant within ±2oC. Using the goniometer furnace, the position of a stationary boundary could be measured with a reproducibility of ±0.3 mm. At elevated temperatures, 500" to 625"C, with the boundary in motion and the X-ray reflection less sharp, the estimated accuracy of each measured boundary position dropped to about ±1 mm. Experimental Results The test pieces were single crystals of 99.6 pet A1 —principal impurities 0.19 pet Fe and 0.12 pet Si— 1 mm by 1 cm in cross section and 6 to 10 cm in length, grown by the strain-anneal method. This relatively low purity material was used because of the difficulty encountered in producing strain-anneal single crystals of very high purity—99.996 pet—

Jan 1, 1957

By A. J. Griest, P. D. Frost, J. R. Doig

During the past 5 years, research directed toward the development of titanium alloys having improved strength-ductility relationships and heat treatability has been carried out at Battelle for the U. S. Air Force.1"3 In the course of this work, a method of heat treating ß-stabilized titanium alloys was developed which produced a wide range of useful properties.4 The heat treatment consisted of two steps: a) solution treating at temperatures in the a-ß phase region, and b) overaging at a lower temperature in the range 800°to 1100°F. Corollary to the alloy development work, research was conducted on the mechanism of the heat-treatment reaction. The investigations of Frost and co-workers on isothermal transformation in Ti-Cr5 and Ti-Mn8 alloys disclosed the existence of the transition phase, w, during the course of the decomposition of metastable ß phase. Subsequent work at Battelle7,8 'and at Case Institute by Brotzen and co-workerss further clarified the nature of the decomposition process. Beta decomposition was found to proceed by the following series of reactions: 1 2 3 4 a + Ti, My (in eutectoid systems). ßo, ßr, and ßU refer to ß phase of original, enriched, and ultimate alloy contents, respectively. Omega is a transition phase having a complex structure. 10-13 Step 4, of course, occurs only in ß-eutectoid systems. This paper presents data correlating transformation behavior with mechanical properties for the following alloys: Ti-8Mn, Ti-8Mn-2A1, Ti-4Mn-4A1, Ti-6Al-4V, and Ti-4Fe. The isothermal decomposition of ß in titanium-manganese alloys of similar composition has been investigated by Frost and coworkers8 and the effect of various annealing treatments on alloys in this system has been studied by Holden, Ogden, and Jaffee.14 The compositions Ti-8Mn-2Al, Ti-4Mn-4A1, and Ti-6A1-4V, were studied in the present work in an effort to define more clearly the effect of aluminum on the response to solution and aging treatments. Ogden, Holden, and Jaffee15 have invesitgated the effect of aluminum on the response of a similar alloy (Ti-8.8Mn-2.46A1) to annealing treatments, and Luini and Lee16 have made an exploratory investigation of the heat-treatability of the Ti-4Mn-4Al alloy. The Ti-4Fe alloy was studied as an example of a moderate1y active eutectoid system. Holden, Ogden, and Jaffee 17 have studied Ti-Fe alloys and have presented some hardness data for aging at 400°C for alloys of Ti-2.56, 5.01, and 7.35 iron after quenching from the a-ß field (750°C). EXPERIMENTAL PROCEDURES The experimental procedures generally used in the precipitation-hardening study are outlined in the following sections. Departures from these techniques are noted in the discussions of the individual alloys. Table I presents the nominal and actual compositions of the alloys studied, together with the swaging and rolling temperatures. In all cases, these temperatures were in the a-ß field and the microstructures consisted of an equiaxed a-ß mixture. Melting and Fabrication—Except for the commer-

Jan 1, 1960

TO THE BOARD OF DIRECTORS OF THE AMERICAN INSTITUTE OF MINING AND METALLURGICAL ENGINEERS Gentlemen:-To a Board of Directors keeping in as close touch with all of the affairs under their care as do the Directors of the A. I. M. E., through their monthly meetings, a report of the year's progress is almost superfluous. ' To the members who read the monthly reports of the Board Meetings and of the various activities of the Institute as published each month, a yearly report cannot carry much fresh information; yet for both it may be well, as is the custom, to glance over the field of our activities during the past year, and to make an estimate for the year to come. The beginning of 1924 was not propitious for the members of the mining profession, though tonnage production for 1923 had been high and the gross value higher than for several years. The margin of profit had been narrow, prospecting and development were limited, and many of our members were unemployed or were working in other industries. Toward the end of the year, higher metal prices were in sight. Old-time optimism began to grow, and it now brightens the outlook for 1925. An excellent barometer of the prosperity of the industry, and that of the Institute, for they go hand in hand, is the work of our Employment Bureau. During the past few months, the percentage of our members for whom openings have been found has been increasing to a marked extent, and many members who had fallen in arrears are placing themselves in good standing. The number of new members joining has remained about as it was in 1922 and 1923. The Directors have reason to congratulate themselves on the interest maintained during a dull period, for it is not humanly possible to take a keen interest in the technology of an industry when our hands and minds are not actively engaged in it Now, with a much brighter outlook, we can look forward to a year of increasing prosperity for the industry and for the Institute.

Jan 1, 1925