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By H. T. Bowman

FOR more than 80 years the Bessemer process has depended upon the ability, skill, and judgment of the blower, although as early as the 1860's it was recognized that the process would benefit by some type of instrumental control.1 However, instruments with sufficient recording speeds did not exist, so the end-point determination was always dependent upon the blower's eye. This placed an obstacle in the way of precise experimental work, because of the absence of the necessary records and reference points as reported by Work.2 The use of the photocell provided the instantaneous record of the blow that made this experimental work possible and provided more scientific control for the process as discussed by Graham3' A brief description of the progress of the blow will illustrate the recording function of the instrument. The silicon in the iron is being oxidized during the first minutes of the blow, as pointed out by Henning4 in a table showing the order of metalloid elimination. The product of this oxidation is a solid that remains in the converter, so there is virtually no flame during this part of the blow. This low flame luminosity is illustrated by the flame recording shown in Fig. I, where the silicon blow is plainly marked. The dull flame of the silicon blow gradually gives way to the brilliant carbon flame as the increasing quantities of carbon monoxide formed inside the converter burn to dioxide upon contact with the atmosphere above the vessel. When the carbon reaches some low value under 0.20 per cent, there is insufficient monoxide formed to maintain the dioxide flame, so its intensity drops. Throughout the flame drop carbon continues to burn, until at some value around 0.05 per cent an arrest occurs in the recorded drop. This point has been designated as the end point. The period of time from this end point until the vessel is turned upon its side and blowing has stopped has been called the afterblow. This afterblow is used as a measure of the degree of metal oxidation, and uniformity demands that it be controlled within narrow limits. Iron and blowing conditions are likely to change several times during a turn, necessitating corresponding changes in end-point control. It is the purpose of this paper to discuss these changes, the factors that make them necessary, and their bearing upon the quality of steel. CARBON-FEO RELATIONSHIP In the Bessemer process oxidation relationships are precise. Fig. 2 shows a graph of the carbon-FeO relationship. The familiar "bomb-test" method, described by McCutcheon and Rautio,5 was used for obtaining these and all other dissolved FeO values herein reported, all tests being taken from the converter before deoxidation unless otherwise noted. All tests of 0.10 per cent carbon and above were obtained from metal blown for duplexing. McGinley and Woodworth6 reported iron oxide values for blown metal, but their tests were obtained by a different method than were those

Jan 1, 1942

By John C. Draper

The principal object of an underground coal mine transportation system is to move coal from the face where it is produced to the outside of the mine where it is prepared for market. In addition to the movement of coal, a transportation system must also move supply materials to the inside; it must move men in and out of the mine; and it must move rock and other debris out of the mine for disposal. Usually, mine haulage is divided into three categories named for the various areas of the mine served : 1) Face Haulage. This is used at face from the mining machine to the intermediate transport system. 2) Intermediate or Secondary Haulage. Generally this is used between face haulage and main haulage. Sometimes this is merely an extension of the main haulage. 3) Main Haulage. This extends from the secondary haulage to the outside and is usually either a track or conveyor system, sometimes a combination of both. Transportation modes of coal in the various areas pose different problems, but the whole system must be synchronized. For instance, at the face the coal should be removed quickly from the various places to facilitate the movement of machines, whereas the intermediate system just passes the same coal on to the main transportation system. Selection of the transportation system must be based on the seam height, mining methods used to extract the coal, capacity required, ease of coal handling, and haulage efficiency. When driving rooms, mine cars can be used. They often simplify supply haulage and rock handling because they can also handle these items. Conveyors could be used and would have a greater haulage capacity but they cannot handle supplies easily or segregate the rock. When using a different mining method, such as longwall, mine cars cannot be used because there is not sufficient space to move the cars at the face nor can the cars haul the coal without delays which would cause excessive losses in production. As for ease of handling

Jan 1, 1981

By D. U. Deere, F. D. Patton

Introduction A close relationship exists between the geologic investigation and the stability analysis of the slopes of an open pit mine. One significant result of this relationship is that the stability analysis is no better than the assessment of pertinent geologic factors that enter into the analysis. In some slope stability problems the engineering solution becomes obvious once the geologic framework is established. In other cases, establishing the geologic framework is only the first stage in the process of analysis. However, even in these cases the geology should not be neglected once the analysis is made. The geology should be periodically reviewed when new slopes are excavated. This will help ensure that the basic assumptions for the analysis have not changed and will permit changes when new conditions are encountered. In recent years improved methods of stability analysis have been accompanied by advances in laboratory testing techniques and new knowledge of the shear strength of rock discontinuities. At the same time there have been improvements in field geological descriptions. As more experience is gained in analyzing and predicting the stability of rock slopes, the importance of certain geologic factors has become more apparent. Some of these factors were described in a paper given at the Open Pit Mining Symposium in Johannesburg, South Africa in September 1970 (I). This paper includes many of the points covered at that meeting but with additional emphasis on the significance of the major geologic structures. Other papers given at the South African symposium also considered geological and hydrogeological factors in slope stability analysis (2) (3) (4) (5) (6). This paper first describes the approach to a slope stability problem including assessment of the relative roles of field geology studies, laboratory testing, stability analyses, and continued slope monitoring studies. Next, is described a framework which has been found useful for classifying or separating the several types of slope stability problems encountered in open pit mines. The principal geologic factors in slope stability problems in rock are discussed and brief comments are made on how these factors distinguish stability problems in rock slopes from those normally encountered in soil slopes. The over-riding control of major geologic structures, especially faults, in most slope stability problems is emphasized. In this regard the relative importance of statistical studies is contrasted with knowledge of the positions of key structural

Jan 1, 1971

By E. S. Machlin, S. Weing

GRAIN boundary stress relaxation has been the subject of several investigations in recent years, but as yet the phenomenon is not well understood. One of the major difficulties has been the lack of a sufficient amount of data with which to evaluate any proposed mechanism. Little information is available on the effect of small amounts of substitutional solutes on grain boundary stress relaxation. It is with this important phase of the problem that this investigation is concerned. The influence of substitutional solutes on grain boundary stress relaxation has been recently investigated in copper by Pearson: and in aluminum by Dorn et al.' Pearson studied the effect of zinc, gallium, germanium, and arsenic on the relaxation peak of OFHC copper.* The pure OFHC copper decreased the peak intensity and a second peak appeared at a higher temperature. This latter peak was termed the alloy grain boundary peak. At the lowest binary concentration studied, approximately 1 atomic pct, the primary peak was almost completely obliterated. Pearson found that the activation energy calculated from the alloy grain boundary peak for all solutes, irrespective of the concentration, was 44,000 cal per mol. Pearson concluded that the increase in activation energy from 33 to 44 kcal per mol is not continuous but abruptly changes from the lower to the higher value. As no attempt was made to investigate the intermediate range of concentration and hence calculate the possible variation of the activation energy for the initial grain boundary peak, this conclusion is hardly valid. In contrast to these results, Dorn et al. studied the effect of zinc, silver, copper, germanium, and magnesium on the grain boundary stress relaxation of aluminum. No change in the energy of activation was observed for binary alloys of the flrst four solutes, but a linear increase was found for increasing concentration of magnesium. Saturation was not found up to the maximum of 1.6 atomic pct. The energies of activation were obtained by plotting the horizontal displacement of the dynamic modulus curve vs temperature for two vibrational frequencies. As the modulus is proportional to the square of the frequency, this requires the measurement of the torsional frequency over a range of temperature. However, the technique does not lead to an unambiguous interpretation of the grain boundary

Jan 1, 1958

By Earl S. Greiner, Eric R. Jette

Although the mechanical and chemical characteristics of certain iron-nickel-silicon alloys have been investigated,1 the available literature shows no results of a systematic investigation of the constitution of this system. 'This paper describes the results of an X-ray investigation of the constitution of the iron-rich iron-nickel-silicon alloys at 600°C. Data 011 the constitution of the included binary systems obtained in other investigations have been correlated with the structure of the ternary alloys. Jette and Foote2 have presented a tentative constitutional diagram of the iron-nickel system. following X-ray studies on quenched specimens. This diagram shows that the alloys at 600°C. containing from zero to approximately 4 atomic per cent nickel consist of a body-centered cubic (alpha) phase, the alloys containing 4 to 24 atomic per cent nickel consist of body-centered cubic (alpha) and face-centered cubic (gamma) phases, and the alloys containing from 24 to Ioo atomic per cent nickel consist of a face-centered cubic (gamma) phase. These investigators recognized that it was not possible to retain the gamma phase in equilibrium by quenching alloys containing less than approximately 25 atomic per cent nickel and that high-temperature X-ray methods were desirable to determine the gamma-phase solubility limit. In a later investigation of the iron-nickel alloys, Owen and Sulley3 determined the alpha-phase solid solubility limit to be 3.5 atomic per cent nickel at 600°C. High-temperature X-ray methods showed the solid solubility limit of the gamma phase to be 14 atomic per cent nickel at 600°C. Since the high-temperature X-ray method should reveal equilibrium conditions in these alloys better than the quench method of other investigators, the results of Owen and Sulley pertaining to the gamma-phase boundary are to be preferred. As the result of an X-ray investigation of quenched iron-silicon alloys, Greiner and Jette4 have shown these materials to consist of a body-centered cubic (alpha) phase containing from o to 26.4 atomic per cent silicon at 600°C. The alloys containing from 26.4 to approximately 50 atomic per cent silicon consist of two phases at 600°C.; namely, alpha and eta. The eta phase corresponds to the stoichiometrical formula FeSi (33.4 wt per cent Si)." The literature pertaining to the constitution of the nickel-silicon alloys has been reviewed by Ackerman,' who found disagreements in the results of various investigators on several parts of the system. Subsequent data on the constitution of the nickel-silicon alloys were reported by oSawa and okamoto.6

Jan 1, 1943

By Paul M. Tyler

MINOR industrial minerals included in this chapter are: the alum minerals, bromine, calcium chloride, epsomite and other natural magnesium salts, iodine, meerschaum, quartz, industrial crystals other than quartz (Iceland spar, tourmaline, fluorite, selenite, mica), and nonfuel gases (air, helium, carbon dioxide). ALUM MINERALS The alums comprise a series of double sulphates (or selenates) isomorphous with potash alum, which, according to a ruling of the Pennsylvania courts, is the only product commercially described simply as "alum." Common alum occurs in nature as kalinite (K2SO4- A12 (SO4) 324H2O). The mineral mendozite (Na2S04) 3.A12 (SO4)3- 24H2O) is soda alum; tschennigite (NH4)2SO4.Al2 (SO4)3.24H2O) is ammonium alum; and there are about a dozen other native alums and related double sulphates. Alunite (alumstone or alum rock) has the formula Al2(SO4) 3.K2S04.4A1 (OH)3 and alunogen, Al2(So4) 3.18H20. Saline residues, found wherever natural water is evaporated, may contain sulphate of alumina, which for most uses is the essential ingredient of alum. Mineral wells and springs that emerge from beds of pyritiferous shale are typically astringent and at times form local deposits of alum, generally as incrustations. Acid waters acting upon aluminous rocks may form sulphates of alumina. The alums of commerce, as well as aluminum sulphate (concentrated alum), are produced principally by treating bauxite with acid, but they have been made also on a substantial scale from clay, cryolite, pyritic slates, schists, lignites, alunite, and leucite. Alum shale-chiefly clay, pyrite, and (usually) carbonaceous matter-was extensively used in England as a source of alum for more than two centuries. In France, pyritic lignites mixed with sand and clay were burned in heaps to red ash, the leach Liquors from which, after treatment with ammonia, yielded alum and copperas. Processes have been developed for making alum or aluminum sulphate from such diverse materials as feldspar, aluminous phosphate minerals, greensand, and mixtures of mica and

Jan 1, 1949

By Elton A. Youngberg

The Holden mine operated by the Chelan Division of the Howe Sound Co. is on the east slope of the Cascade Range in north central Washington on the south slope of Railroad Creek valley at an elevation of 3500 ft. The mine may be reached by a 40 mile boat trip from the town of Chelan which is at the southern tip of Lake Chelan, to Lucerne at the mouth of Railroad Creek and an 11. mile bus ride up Railroad Creek to Holden. A11 freight and concentrate is moved over this route to Chelan Falls on the Columbia River which is on the railroad four miles below the town of Chelan. The mine is now producing 2000 tons of gold, copper, and zinc ore per day which is treated in the Holden mill. Gold-copper and zinc concentrates are made, the first of which is shipped to Tacoma, Wash., and the latter to Kellogg, Idaho, for smelting. Ore is broken by long-hole blasting using the Noranda system which has been modified to meet local conditions. Until recently, blastholes have been drilled by diamond drills. Now a partial substitution of percussion drill holes, drilled with tungsten carbide insert bits, is being made. Geology The ore body occurs as a replacement deposit in a highly metamorphosed series of sedimentary rocks, mainly gneiss and schists, in a shear zone several hundred feet in width and of undetermined length. Commercial ore has been found in mineable widths of 25 to 100 ft for approximately 2500 ft along its strike. The commercial minerals are chalcopyrite, sphalerite, and gold. During the period of mineralization considerable silicifica-tion took place giving the ore an abrasive drilling characteristic. Following the period of mineralization, numerous dikes were introduced into the ore body. The earlier ones were of granite composition having a width of a few inches up to 80 ft. These were followed by much younger, fine grained basic dikes which usually do not exceed 2 ft in width. Development of Percussion Blasthole Drilling Equipment Test work with the 1½-in. tungsten carbide bit was carried on in development headings for several months early in 1947. The short life of the bits, because of gauge loss caused by the abrasive nature of the rock, prevented its adoption for this use. However fast drilling speed and ability to drill a long uniform hole suggested its use for drilling blastholes in competition with diamond drills as diamond costs were steadily increasing and exper-ienced drillers were difficult to obtain. The 1½-in. bit was the largest available at the time initial test work was started with sectional steel. The 1½-in. hole limited the diameter of the steel thread and coupling which could be used. Type F couplings were first used but because of the small thread section excessive breakage of the steel was experienced. Type H couplings were tried next. In order to use this coupling which is 15/8 in. in outside diameter, it was reduced to 1 3/8 in. giving 1/8 in. clearance between the coupling and the hole. Rod breakage at the thread was substantially reduced but some coupling breakage was experienced, however the overall performance was considered satisfactory (see Fig 1 for illustration of coupling and thread). Early test work with the 1½ in. bit indicated machines of piston diameters larger than 255 in. would cause inserts to loosen or break. It was found however that the additional weight of the sectional steel cushioned the blow enough to prevent bit failures when 3-in. Leyners were used. Rods used with the 1½-in. bits were 7/8 in. q. o. for sectional steel and 1 in. q. o. for all chuck pieces. In May 1948, 2-in. tungsten carbide bits became available and test work was immediately started. The 2-in. hole approximated the AX (1 15/16 in.) diamond drill hole which was being used exclusively for blastholes and permitted their substitution for diamond drill holes in a ring without alteration of pattern, burden, or explosives. The 2-in. bit also gave room in the hole for larger couplings and permitted the use of heavier rods and 3½-in. machines, increasing the

Jan 1, 1950

By R. V. Taborelli, P. B. Bucky

This investigation was carried on by means of models and the application of the principles of similitude to determine the effects of props, props and cribs and sand filling in longwall mining. The geologic structure and rate of face retreat were kept constant and the only change introduced was in the method of support. It is not felt necessary to repeat a description of apparatus, or to explain the fact that a scalar model made in all parts of the same material as the prototype will behave similarly to the prototype when rotated at speeds such that the centrifugal force is as many times the gravitational force as the prototype dimension is a similar linear model dimension. The reader is referred to earlier papers1,2 for further information regarding these statements. All models were made of sandstone and were as in Fig. 6. They are composed of a 3/16-in. ore body bed A, overlain by a 3/16-in. bed B, a ?-in. bed C and two ?-in. beds D and E. The model was rotated at + 2350 r.p.m. equivalent to a model ratio of 1268. It was worked back ¼ in. at a time before being replaced in the centrifuge and again rotated. Table 1 gives model and prototype dimensions occurring in this discussion, the prototype dimensions being 1268 times the model dimensions. Figs. 1, 2, 3 and 4 were taken while the model was rotating at 2350 r.p.m. One was taken for each face retreat of 26.4 ft., but for obvious reasons all are not presented. Fig. 1 (A-E) shows the behavior of this type of structure with face retreats of 26.4 ft. and no artificial support. Fig. 2(A-E) shows the behavior of this type of structure where breaker and face props were used. The props were exceptionally strong, being of steel ? in. square in cross section, and capped with 1/16 in. ± of soft wood and paper, to allow for roof deflection. The face props were

Jan 1, 1940

By E. I. Salkovitz, F. W. von Batchelder

DURING the last few years several papers1-' have been published in which internal friction measurements have been used to determine the quantity of carbon or nitrogen dissolved in a iron. This method is based on the fact that, in pure Fe-N and Fe-C alloys, nitrogen and carbon cause peaks in the internal friction vs. temperature curve; at a frequency of 1 cycle per sec (cps) these peaks appear at $-200 and +360C, respectively, and if internal friction is expressed as Q-1, which is equal to times the logarithmic decrement, this figure will, by coincidence, give the weight percentage of nitrogen or carbon in solid solution.' In most of the studies published, very pure iron (Puron) was used. In one case the influence of manganese on the behavior of nitrogen in a iron was mentioned.4 It would be of great value, especially for the study of aging and related phenomena, if this method could be applied to commercial mild steel with norrnal percentages of manganese, phosphorus, sulphur, etc. As a rule, in such steels carbon and nitrogen are present together, and the amounts of these elements in solid solution should preferably be determined separately. The fact that their internal friction peaks appear at different temperatures (+36° and + 20°C in pure iron) seems promising for such a selective determination. It is necessary, however, that the peaks are narrow enough not to interfere with one another, and further, that there is no effect from carbon on the behavior of nitrogen in stress induced diffusion, and vice versa. According to Fast,' however, in the presence of manganese the nitrogen peak gets wider and appears at a higher temperature nearer the carbon peak, and thus the prospects for selective determination are reduced. (The carbon peak was not affected by the presence of manganese.) But even if fully quantitative de- terminations of the two elements are not attained, some relative figures on the sum of them and an indication of which one is the predominant one, would be of value. Some results from experiments along these lines will be reported here. An internal friction measuring device was assembled mainly following a description by KG." The measurements were also carried out as reported in that paper. Table I gives the chemical compositions of the four different materials used in this investigation. All materials were drawn to wires with diameter about 0.8 mm, and the analyses refer to these final shapes. Determination of Nitrogen Peak Wires from steels A, B, and C were decarburized in wet hydrogen (about 30 pct H2O) at 700°C until no carbon or nitrogen could be found by chemical analysis. No peak was then found in the internal friction. The wires were further annealed at 580°C for 16 hr in hydrogen bubbled through a solution of 6.8 pct NH3 in distilled water. Chemical analyses gave 0.04 pct N in A and C, and 0.06 pct in B. After annealing at 580°C for 15 min in a lead bath and water quenching, the internal friction was immediately measured. The resulting curves are shown in Fig. 1. At these high values of the internal friction the accuracy is comparatively poor; at Q-1 - 0.030 it is estimated to be 0.002. In order to make possible a calculation of the activation energy for diffusion of nitrogen, measurements were made at two different frequencies. Steel A shows rather broad peaks, and their temperatures can hardly be expected to be very accurate. Steels B and especially C are better in this respect. The finding of Fast' that manganese broadens the nitrogen peak is con-

Jan 1, 1953

By L. W. Pommier, F. B. Brien

The Rheological properties of pulps are non-Newtonian in character and more than one viscosity parameter is necessary to describe their behavior, therefore, the single term 'apparent viscosity' which has been used in the past may be misleading. The study reported in this paper uses a dimensional analysis based on the Ostwald-de Waele shear stress-rate of shear model for non-Newtonian liquids to develop velocity and resistance equations for falling spheres. An electronic monitoring apparatus was assembled for determining the velocity of metallic bodies as they fall through opaque liquids and suspensions. By means of this apparatus the behavior of the viscosity parameters of the Ostwald-de Waele model and the applicability of the proposed equations were examined for a number of non-Newtonian liquids. The validity of the equations for these liquids was confirmed. Preliminary data collected using solid-liquid suspensions established the validity of the form of the basic equations for these systems. The differential movement of solid particles through solid-liquid pulps and suspensions is very important LO many branches of engineering, such as minerals processing, soil mechanics, ceramic slip processing, oil well drilling-mud technology, materials-handling in pipelines, and many others. There is a dearth of fundamental knowledge on the flow resistance encountered by immersed bodies moving through solid-liquid suspensions. The resistance offered by Newtonian liquids to the movement of free settling spheres is well described for laminar and turbulent conditions by Stokes' and Newton's Laws, respectively. However, problems are encountered when attempts are made to extrapolate these simple relationships into solid liquid suspensions. The rheological properties of pulps are such that they are non-Newtonian in character;'" that is, the applied shearing stress and resulting rate-of-shear are related by non-linear functions, and thus, in the simplest case two viscosity parameters are necessary to describe their rheological properties. For this reason the single term 'apparent viscosity' which has been commonly used to explain the flow resistance of suspensions and non-Newtonian liquids may be misleading. It is realized that a rigorous analysis of the rnechanisms of momentum transport of liquid-solid systems is complex indeed. There are many variables that affect the rheological properties of the systems such as density, size, shape, and surface energy of the suspended solid and density and viscosity of suspending liquid, as well as the solid to liquid ratio. However, it was felt that a useful contribution to the knowledge of the behavior of suspensions could be made by examining the systems in terms of the basic fundamentals of nowNewtonian flow. This has led to the development, by means of dimensional analysis, of velocity and resistance equations, using two viscosity parameters to describe the velocity of penetrating bodies and the flow resistance encountered by these bodies, as they pass through non-Newtonian systems. THEORY In order to examine the effects of the rheological properties of solid-liquid suspensions on the movement of immersed bodies it is appropriate to start with non-Newtonian liquids and develop equations, analogous to those of Stokes and Newton, for laminar and turbulent flow respectively, from which quantitative information may be obtained. Further investigation would then be directed at the complex suspension systems, and the effects of the many variables on the velocity and resistance equations. Liquids are classified on a basis of viscosity which may be defined as the relationship between applied shear stress and resulting rate of shear?-'* Pure single phase liquids composed of small light molecules behave as Newtonian liquids, having a single viscosity parameter since the shearing stress and rate-of-shear are related by a linear function. Bingham plastics are similar but have a yield stress. Of particular importance in our investigation are dilatant (shear thickening) and pseudoplastic (shear thinning) non-Newtonian liquids, with and without yield values.

Jan 1, 1968

By P. B. Bucky, R. V. Taborelli

This investigation was carried on by means of models and the application of the principles of similitude to determine the effects of props, props and cribs and sand filling in longwall mining. The geologic structure and rate of face retreat were kept constant and the only change introduced was in the method of support. It is not felt necessary to repeat a description of apparatus, or to explain the fact that a scalar model made in all parts of the same material as the prototype will behave similarly to the prototype when rotated at speeds such that the centrifugal force is as many times the gravitational force as the prototype dimension is a similar linear model dimension. The reader is referred to earlier papers1,2 for further information regarding these statements. All models were made of sandstone and were as in Fig. 6. They are composed of a 3/16-in. ore body bed A, overlain by a 3/16-in. bed B, a ?-in. bed C and two ?-in. beds D and E. The model was rotated at + 2350 r.p.m. equivalent to a model ratio of 1268. It was worked back ¼ in. at a time before being replaced in the centrifuge and again rotated. Table 1 gives model and prototype dimensions occurring in this discussion, the prototype dimensions being 1268 times the model dimensions. Figs. 1, 2, 3 and 4 were taken while the model was rotating at 2350 r.p.m. One was taken for each face retreat of 26.4 ft., but for obvious reasons all are not presented. Fig. 1 (A-E) shows the behavior of this type of structure with face retreats of 26.4 ft. and no artificial support. Fig. 2(A-E) shows the behavior of this type of structure where breaker and face props were used. The props were exceptionally strong, being of steel ? in. square in cross section, and capped with 1/16 in. ± of soft wood and paper, to allow for roof deflection. The face props were

Jan 1, 1940

"The Murray Plant of the American Smelting & Refining Company is situated seven miles south of Salt Lake City, and has a fine view of the Salt Lake Valley with its fertile farms and orchards.It is located on the Los Angeles & Salt Lake and Denver & Rio Grande Western Railroads, and has a fine electric car service, cars running every 15 minutes.The beautiful and majestic Wasatch Range lies about five miles to the east and the Oquirrh Range to the west, and from these mountains a large proportion of the ores treated are obtained.The location is very central, ores coming to the plant from all directions. Park City, where a large tonnage of high grade silver-lead ore is obtained, lies to the east and the camp of Alta is just across the mountains from Murray.To the west is the wonderful camp of Bingham, which produces a large tonnage of lead ores, in addition to its immense tonnages of copper ores, which are treated at Garfield.Tintic, to the south, sends in quantites of dry silicious ores, as well as silver-lead ores.Besides the above, ores are shipped to the plant from Stockton, Ophir, Milford and other camps in Utah, as well as from Nevada and Idaho, and also some ores from Cali¬fornia, Oregon, Washington, Wyoming and Colorado.The American Smelting & Refining Company took possession in 1899 of its Utah properties which consisted of the following plants, all of which have been dismantled:"

Jan 1, 1925

By Lyon F. Terry

INCREASING domestic demand for products, a sharp reduction in exports to Europe, and a rise in imports from South America were the chief features of the economic side of the industry in 1940. As the war progressed it became evident that exports to former European customers were being cut off or drastically reduced, leaving heavy inventories of products in the hands of many American refiners who had anticipated larger demands from the belligerents. Stocks of motor fuel reached burden-some proportions early in the year for the added reason that refining operations were stimulated by heavy demand for heating oils. Excessive tanker rates for Gulf to Eastern Seaboard movements during the first part of 1940 contributed to the accumulation of products on the Gulf Coast, where refinery gasoline prices were forced to extremely low levels by midyear. Tanker rates receded to normal during the summer but have since risen again to the approximate equivalent of pipe-line tariffs from the Mid-Continent.

Jan 1, 1941

By C. P. Lawhon, J. P. Simpson, W. M. Evans

Data obtained under controlled test conditions using a microbit drilling machine showed that oil emulsified in water muds may either increase or decrease the drilling rate, depending upon drilling conditions. A low-viscosity oil such as diesel fuel can give drilling rates in limestone almost equal to that of water. Data obtained for water emulsified in oil muds showed little decrease in the drilling rate in water-saturated cores as the water percentage of the mud was increased above the 5- to 10-percent range. Changes in drilling rate were found to be dependent upon the oil or water concentration of the mud and upon the type of formation drilled. Changes in static filtration on paper (API filtrate) did not correlate with filtration while the mud was circulated across rock. INTRODUCTION Oil additions to water muds have been reported to increase drilling rates, provide hole stability and improve filtration control. Eckel' showed that water-base emulsion muds used in the West Texas area increased drilling rate with increasing oil concentration up to 15 percent oil by volume, but drilling rate decreased at a concentration of 20 percent by volume. Based on laboratory tests using water muds to drill shale, Cunningham and Goins' reported that drilling rates increased and tendency for the bit to ballup decreased with the addition of oil. Percentage increase in drilling rate varied with the particular formation. They showed oil additions to improve drilling rates ap proximately 75 percent in Vicksburg shale and as much as 150 percent in Miocene shale. Each investigation showed an optimum oil content for the particular formation. Most data that indicated improved filtration control due to oil additions were based on static API Eltrates through paper rather than dynamic filtration through permeable rocks. Some types of dynamic test give a better representation of filtration down-hole while drilling and might be more likely to show some correlation with drilling rate. Static filtration would be important, of course, in relation to hole stability and formation damage. This laboratory's drilling tests, conducted on water-raturated Berea sandstone, indicated that improvements in drilling rate were not evident with increasing oil concentration in water-base muds. Investigation also showed similarity between oil-emulsion (water-in-oil) muds and water-emulsion (oil-in-water) muds while drilling these formations. In Lueders limestone high concentration of water-in-oil muds and high concentration of oil-in-water muds provided the same relative drilling rates. In Berea sandstone there was a large reduction in relative drilling rate with both the oil and water muds that contained low percentages of emulsified fluid. Dynamic filtration rates of water muds on rock did not always decrease with increasing oil percentages even though the static API filtration rates on paper did decrease. Data observed in laboratory drilling of limestone and sandstone indicate that improvements in field drilling operations when water- or oil-emulsion muds are wed may not be the result of increased drilling rates but of improved hole conditions. In some cases, actual drilling rates might be slower but improved hole conditions will result in less total time on the hole. DEFINITIONS Mud pressure—Pressure of drilling fluid as measured after leaving the drilling chamber. This is considered as the approximate mud pressure just past the bit and at the face of the formation. Terrastatic pressure—Pressure representing weight of overburden. Formation pressure—Pressure of formation fluid as measured at outlet of drilling chamber. This is considered as approximate pressure of fluid in the pores of the formation. Differential pressure—Difference between the mud pressure and formation pressure. Relative drilling rate, percent—Drilling rate with experimental fluid divided by drilling rate with water times 100 equals percent. LABORATORY EQUiPMENT AND TESTING PROCEDURES The drilling equipment has been described in previous publications The microbit drill is a closed system (capacity, approximately 7 gal) that can be pressurized to 15.000 psi and heated to 500F. Main components are a drilling chamber, filter-heater, rotary-drive and variable-speed cir-

Jan 1, 1943

By H. Macpherson

Durhm has a well earned reputation for supplying some of the finest coking caals in the world. The caals, in general, vary in rank from 301 to 501/2. Durham has traditionally produced foundry coke for the major proportion of the foundries in Great Britah. Durham coals can be described as clean, soft coals, which yielded, with the old hand methods of coal getting, low ash small coal because the extraneous shale was normally harder than the coal and occurred in larger pieces. Under these conditions, with a plentiful supply of cheap labor, it used to be sufficient, at most collieries, to hand clean the large sizes of coal which could then be remixed with the untreated small coal to produce carbonization coals, ready for the coke ovens, at under 5 pct ash. With the introduction of mechanical methods of coal mining, the coal gradually required more cleaning. The first method adopted to resolve this problem was the introduction of pneumatic dry cleaners for the small coal. Although such machines had little effect on the fine coal (say below 1/8 in.), they could clean the intermediate sizes of coal. This, coupled with hand cleaning the larger sizes above 1-1/2or 2 in., resulted in a combined run-of-mine mixture below 6 pct ash, capable of maintaining the quality and reputation of the cokes produced. In more recent years, the intensification of mechanization and power loading, coupled with gradual exhaustion of the cleaner seams, has created the need for a more complete method of coal cleaning. This particularly applies in the fine sizes (say below 1/50 in.) which normally vary, under present day conditions, between 15 and 35 pct ash and are much too dirty to be included in the raw state in a carbonization mixture. This pronounced change has been accelerated because legislation controlling the dust conditions of mine airs for the prevention of pneumoconiosis has resulted in tk~e extensive use of water underground and a consequent increase in moisture content of the run-of-milie output. The presence of damp fine coal decreast the efficiency of prescreening and dry cleaners, so that this type of preparation for low ash coking coals is decreasing, although it is still used satisfactorily for industrial coals in the medium ash range. Table I shows the gradual increase in mechanization, the reduction in manpower, the increased use of explosives per ton of coal extraction, and the increase in the proportion of coal cleaned by mechanical means in Great Britain. Although similar figures are not available for Durham Div. until after the date of nationalization of the coal industry, it is probable that the increase in mechanical cleaning, particularly by dry cleaners, was more marked in the Durham collieries than elsewhere in the country. As dry clealiers were replaced by coal washeries in the Gritish ccal industry, no special attempts were made to recover the slurry, with the result that large outflows of dirty water were allowed, deposits of slurry came in to lagoons and neighboring streams, and a proportion of fine material was lost from the coking coal. This position, coupled with the higher moisture of the washed coking coal, resulted in adverse effects on coke oven throughputs and coke quality. It is now realized that the natural coal fines are an essential ingredient of coking coals in obtaining the correct coke structure in metallurgical cokes. This, together with economic pressure, led to the introduction of flocculation and filtration plants for the recovery of slurries, and later, when the ash contelits of the filter cakes were too high, to the introduction of froth flotation equipment. After this position had been reached, the tailings from the froth flotation pIants were, in many cases, still allowed to constitute an undesirable effluent. Recent legislation on river pollution has changed this picture; it is now necessary to provide a circuit which is completely closed so far as solids are concerned. The gradual increase in the coal cleaned by wet methods and froth flotation in Durham Div, is shown in Table 11. It is now an accepted feature of new Washeries that. froth flotation should be an integral part of the washing process from the initial installation of the plant.

Jan 1, 1962

Jan 1, 1889

Jan 1, 1943

[Abad. Leopoldo F., Min. Engr., Div. of Mines, Bureau of Science Manila, P. 1. '28 Abadilla, Quirico A., Geol., Lago Pet. Corp Box 172, Maracaibo, Venezuela. '20 Abarquez, Ramon F., Met., Bureau of Science Manila, P. I. '24 Abbey, Robert Graham, Student, Case School of Applied Science Cleveland, Ohio. '21 Abbott, A. N., Mines Supt.. Mazapil Copper Co,, Ltd Concepcion del Oro, Zac,, Mexico. '28 Abbott, Clarence E., Mgr,, Mines & Quarries, Tenn, Coal, Iron & R. R. Co., 1242 Brown Marx Bldg,, Birmingham, Ala. '04]

Jan 1, 1928

By G. Sandoz, D. A. Meyn

The fracture surfaces of specimens of titanium a1loys which exhibited susceptibility to subcritical crack growth in a wide variety of environments, including aqueous solutions, alcohols, hydrocarbon gases, carbm tetrachloride, and dry air, were examined. The dominant and characteristic fracture mode was cleavage. which became mixed with an increasing porportion of ductile fracture modes (dimples. and so forth) as the applied KI was increased. The cleavage plane in all the alloys was oriented at 15 deg from (0001) of the a phase. No indices could be assigned to the 15 deg cleavage Plane because of uncertainty as to which zone it belonged to. SLOW crack growth and delayed fracture take place in certain titanium alloys at stress intensity (KI) lower than the critical values for complete fracture (KIc) found in short-time tests for plane strain fracture toughness.' Such crack growth may take place in very dry air on sustained loading if the alloy contains a sufficient amount of hydrogen and if the stress intensity factor is higher than a threshold value designated KIH.2 Similarly, a number of environments such as water, alcohols, and hydrocarbons may cause slow crack growth provided the stress intensity factor exceeds the threshold value KISCC. In this paper it is intended to examine some fracto-graphic and crystallographic details of this subcritical crack propagation process as related to alloy composition, environment, and stress intensity. It has been previously reported that subcritical crack growth takes place in titanium alloys in aqueous environments by cleavage.2"6 The observations to be described here indicate that in the alloys investigated the mode of subcritical crack propagation is more dependent on the stress intensity during cracking than on the environment. The fracture mode is illustrated with photographs of the fracture surfaces at a wide range of magnifications. The crystallographic character of the cleavage mode is also presented and the results discussed. EXPERIMENTAL APPROACH The studies were made on four titanium alloys— Ti-8A1-1Mo-lV, Ti-5A1-2.5Sn, Ti-7Al-1Mo-lV, and Ti-0.350. Of these four alloys the first two were mill annealed and fine grained. The latter two were noncommercial and coarse grained, having been prepared for other experimental purposes. The crystallographic studies required a large-grain size. Consequently the fine-grained alloys were an- nealed in a vacuum at 1950°F and furnace cooled to produce samples for these studies. This treatment did not alter the microstructure significantly except for grain size. All the aluminum-containing alloys showed primary a with a network of ß-phase particles within the a grains; Figs. 1 and 2 show this microstructure for the specific case of fine-grained Ti-8A1-1Mo-1V. The cracks in the figures will be discussed later. Fractographic studies were made on all the alloys, but the electron fractographs displayed herein are from the Ti-8A1-1Mo-1V alloy in the fine-grained condition. Emphasis was placed on this commercial alloy because considerable information was available on the stress-corrosion cracking characteristics in a variety of environments. Sufficient supplementary studies of the alloy after the anneal to produce large grains were conducted to establish that the stress-corrosion cracking susceptibility and fractographic characteristics were not changed significantly. Thus it could be inferred that the crystallographic data obtained exclusively on large-grained specimens would apply also to fine-grained specimens. Fracture surfaces for study were obtained using precracked cantilever beam specimens loaded as described by Brown. The precracked section of a specimen was immersed in the environment of interest. Values of initial stress intensity factor Kli were chosen slightly higher than KISCC in order to obtain a fairly extensive region of slow crack growth. Fracture surfaces representative of a variety of stress intensity levels could then be examined because in the cantilever beam test KI increases as the crack propagates.

Jan 1, 1970