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By R. M. Schuster, F. M. Benavides

A plan is prepared to develop and operate a four mine complex over a 30-year period. The mining complex is in the vicinity of two existing processing plants and the most economical means of transporting the raw minerals to either or both of these processing plants is sought. The mines and processing plants are all within a radius of 5.6 km (3.5 miles). Existing transportation facilities consist of county and state roads and federal highways as well as haul roads in some areas. A navigable river meanders through the area under study and there are two railroad systems servicing the area. The analysis shows the economic and operational feasibility of using an overland conveyor in lieu of other means of transportation.

Jan 1, 1983

By Philip H. Nelson, Richard Lingle

Vibrating wire stressmeters (VWS's) and borehole deformation gages (BDG) were deployed in two in-situ heater experiments at Stripa, Sweden to determine the thermally induced stress changes in the rock mass. The heater experiments ran for 18 months, including a six- month cool-down period after the heaters were turned off. Gages were installed in both horizontal and vertical boreholes and were subjected to temperatures ranging from 10°C to 120°C, depending upon the distance of a gage from the central heater. Most gages operated in a moist environment because groundwater flowed into many of the instrument boreholes during the experiments Of the 36 VWS's installed, six failed. Failures were attributed to corrosion of the vibrating wire due to moisture entering the gage body. Of the 30 BDG's installed at the beginning of the experiments, 22 failed, also as the result of water entering the gage body. Modification and reinstallation of the gages eliminated the problem of water infiltration, but much data from early stages of the experiments was lost due to gage failures. Calibration of the VWS in blocks of Stripa granite showed a lack of repeatability. Variability in calibration results are attributed to seating effects, to variations in the elastic modulus of the rock, and to changes in temperature. These three effects combined to produce an error judged to be approximately ±33% of the stress changes measured at Stripa. In contrast, the major source of error in determining stress with the BDG appears to be the uncertainty in rock modulus and thermal expansion coefficient. Sample calculations based on data acquired near the end of the experiments (during cool-down)

Jan 1, 1982

By R. J. Keene

The South Works high-tonnage billet caster was started in late March 1971, with the first heat being successfully cast to completion. Currently, over 31,500 tons per month are being produced. U. S. Steel designed and built this caster with the objective of producing quality-steel billets for critical bar, rod, and wire applications. The essential design parameters were based on studies conducted on the Research Laboratory's pilot caster, also located at South works. 1,2,3)* The caster is a four-strand, straight-mold machine that produces 7.5-inch- square billets at rates exceeding 300 tons per hour. An in-line-reduction mill reduces each strand to either 6-inch-, 5-inch-, or 4-inch-square billets.

Jan 1, 1972

By Rebecca Mae Summer

Increasing urbanization and industrial activity require increased supplies of sand and gravel. This means expanded surface mining and despoiled land near population centers. Highly competitive land use demands justify serious consideration of premining planning for multiple land use and reclamation concurrent with mining, 1-5 Formulating solutions to environmentally and economically sound uses requires a comprehensive approach based on properties of the natural resource base--geology, soils, and water. A study of sand and gravel mining within Pleistocene-Holocene fluvial deposits in Colorado County, Texas (Fig. I) illustrates how physical limitations imposed by the resource base are determined.6,7 Data from drillers logs of water wells, test boreholes, field observations, and laboratory analyses are used to evaluate these physical controls.

Jan 1, 1978

By M. G. Magnuson, H. O. Hofman

When dry chlorine gas is made to act in the cold upon fiuely-divided gold,' it converts the latter with evolution of heat into auro-auric chloride, Au4 Cl4, a hard, dark-red, hygroscopic salt. Moisture splits this salt into aurous and auric chloride, Au²C14 = AuCl + AuCl³; treatment with water converts it into auric chloride and gold, 3 Au²CI4 = 4 AuC1³ + Au². Aurous chloride, when stirred with water, undergoes a similar decomposition, 3 AuCl = AuCI, + Au,. These decompositions of auro-auric chloride and of aurons chloride furnish the explanation for the practice of moistening an ore before it is treated by the Plattner chlorination-process; practical experience having shown that gaseous chlorine gave an unsatisfactory extraction with dry ore. According to Rose12 fine gold is acted upon more slowly by chlorine than gold containing some base metal, e.g., copper. He also says that small quantities of silver increase the rate of solution, but adds that the coating of silver chloride formed, checks, and finally stops, further action, if the percentage of Silver be increased beyond a certain undetermined amount. Bromine3 acts upon finely-divided gold in a manuer similar to chlorine; the auro-auric bromide, Au²,Br4,, however, is not hygroscopic. Upon treatment with water it is decomposed as is the corresponding chlorine salt. It is generally believed that bromine does not act as energetically upon gold as does chlorine. This seems to be borne out by the results in the leach- +1MASSACHUSETTS INSTITUTE OF TECHNOLOGY, BOSTON, MASS.

Jan 1, 1905

TO metallurgists generally, Arthur S. Dwight is no stranger even to those who do not know him personally. He is one of those contributors to technical progress whose names will go down to posterity because of their being attached to a successful machine or process, such as Dorr, Hardinge, or Marcy, or Wedge, MacDougall, or Herreshoff. The roasting and sintering method and equipment developed by Colonel Dwight and his associate, the late Richard L. Lloyd, may be found in lead smelters throughout the world, and also in many metallurgical works dealing with other ores, including those of iron. It is ordinarily used to desulphurize and agglomerate fine ores for subsequent smelting. Colonel Dwight's citation as James Douglas Medalist reads: "For his contributions to the art of smelting nonferrous ores; and particularly for his pioneer work in developing equipment and technique for sintering such ores and metallurgical products." The medal was awarded at the last Annual Meeting of the A.I.M.E. but unfortunately the medalist was unable to leave Florida at the time to receive it in person.

Jan 1, 1942

By D. W. Duncan, A. Bruynesteyn

An ore containing chalcopyrite was microbiologically leached in 6 ft columns at particle sizes ranging from -2 +1 ½ inches, to -3/8 + 3/16 inches. The rate of leaching increased exponentially as the particle size decreased. The controlling factor was the active leaching volume made up of the particle surface area and the depth of penetration of the bacteria and leach liquor into the particle. This volume became an increasingly larger part of the total volume as the particle size decreased. The sample under test leached poorly at larger particle sizes and it was calculated that under commercial conditions, it would produce at best a pregnant solution containing 100 mg/l (0.2 lb/ ton) of copper per 100 ft of dump height.

Jan 1, 1974

By B. Yarar

Samples of coal from an adit in the Fording River District of British Columbia showed hydrophilic properties between depths of 0-24.5 m (0-80 ft) and was naturally hydrophobic at greater depths. Laboratory experiments indicated that weathered samples (i.e., those mined at 0-24.5 m) could be upgraded by froth flotation at pH32 following slimes removal. The i.e.p. of samples varied regularly between pH = 1.6-4.1, the weathered fractions being at the lower end of the pH scale. These values followed a pattern comparable with the flotation behavior of samples. A patchwise structure for coal surfaces determining the resultant disjoining pressure which in turn determines flotation-non-flotation relationships is postulated.

Jan 1, 1983

Two 6.17-m-diam (20.25-ft) shafts, said to be the largest ever opened with mechanical raise boring techniques, were completed in May and June 1978, at Monterey Coal Co.'s No. 1 mine near Carlinville, Ill. According to the shaft contractor for the project, Frontier-Kemper Constructors, the openings are 60% greater in cross section than the largest previous raise-bored shaft, which had a diameter of 4.85 m (16 ft). Both vertical shafts are 93 m (305 ft) in total depth, with the upper 28-30 m (90-100 ft) sunk and lined by conventional methods through unconsolidated overburden and the remainder mechanically bored through sedimentary rock. The two shafts will be used for service access as well as to augment ventilation.

Jan 12, 1978

THE first session of the production engineering group on Wednesday, morning, with J. B. Umpleby as chairman, recorded the principal developments since the Fort Worth meeting. Added to this was a lively discussion of pressure maintenance. Recent advances in the air-gas lift have resulted from the need of applying the method to smaller wells at lower costs. In many places intermittent flow has given excellent results, and numerous mechanical de-vices for its automatic control have been, developed. Papers by C. V. Millikan on the Mid-Continent field and by A. H. Bell on California, fields formed the basis for discussion. The maintenance of initial sand pressures was ably discussed for two Texas fields by t. V. Foran in a paper that not only outlined the technic of operation and the results obtained but also contained noteworthy cost data in terms of increased ultimate production. Mr. Foran recommends the use of air in the first stages of pressure maintenance as a means of determining sand conditions and directions of flow, later turning to gas, if available, because of its greater solubility on oil. A round table discussion on petroleum engineering educational problems, with H. G. George as chairman, brought out much interesting discussion that is difficult to summarize. The other Wednesday morning session was a refinery engineering symposium with T. G. Del-bridge as chairman and the economical application of heat for the general topic. A paper on the modern pipe -still, by H. S. Bell, and another by C. W. Stratford on the modernization of the cylindrical still elicited a lively discussion.

Jan 3, 1928

By Mario L. Villa

During the year 1941, there was another increase in the production of oil in Argentina, to which the fields in the Comodoro Rivadavia zone in the Territory of Chubut and those of the Provinces of Salta and Mendoza all contributed. The total production for this period reached 22,013,472 bbl., which represents an increase of 6.8 per cent over that of 20,609,538 bbl. in the preceding year. This result is again attributable to the Government oil company, the Yacimientos Petroliferos Fiscales, which had a total production of 14,006,559 bbl. representing an increase of 1,531,904 bbl., or 12.3 per cent over that of the 12,474,655 bbl. of the year before. The other companies

Jan 1, 1942

By Mario L. Villa

During the year 1941, there was another increase in the production of oil in Argentina, to which the fields in the Comodoro Rivadavia zone in the Territory of Chubut and those of the Provinces of Salta and Mendoza all contributed. The total production for this period reached 22,013,472 bbl., which represents an increase of 6.8 per cent over that of 20,609,538 bbl. in the preceding year. This result is again attributable to the Government oil company, the Yacimientos Petroliferos Fiscales, which had a total production of 14,006,559 bbl. representing an increase of 1,531,904 bbl., or 12.3 per cent over that of the 12,474,655 bbl. of the year before. The other companies

Jan 1, 1942

By M. Lastra, A. Cruz, J. Menacho

The use of phosphates was studied as a way of purifying acidic copper leach solutions for direct electrowinning. The addition of 2.5 gpl phosphorus to plant solutions originally containing 6.25 gpl Fe (III) at pH 2 0 reduced the iron concentration by one half. Under identical conditions, but without phosphorous additions, the iron concentration was reduced by less than 1 gpl. Any residual phosphorous had no undesirable impact on electrowinning. The concentration ratio of Fe (III) to phosphorous which provides maximum iron elimination was determined. Higher ratios bring about a redissolution of the iron precipitate. Several ways of controlling iron with phosphates are discussed. These take advantages of more rapid and complete iron precipitation at lower pH levels.

Jan 1, 1980

By Frank J. Anderson

IN the cement region of the Lehigh Valley, a difference of 2 to 3 pct in CaCO3 can make or break a new quarry development, and experience of the Dragon Cement Co. has shown that values of calcium carbonate, as reported from churn drill samples, have been increased as much as 6 pct on the average when the same area was diamond drilled. This calcium carbonate increase consequently lowered the values for silica, iron, and alumina, and made these sections much more attractive. Since 1950, the Dragon Cement Co. Inc. has been engaged in extensive diamond drilling in the local limestone of the Northampton, Pa., region, known as the Jacksonburg formation, and in the Lebanon, Pa., region in the Annville limestone, both of Ordovician age.

Jan 12, 1954

By F. C. Newton

REFINERS of lead by the Parkes process have always been solicitous of recovering the zinc used in the desilverization, and justly so, as the loss in zinc constitutes one of the heavy costs in this method of refining. Part of this loss is due to the absorption of zinc by lead, and in the present state of knowledge is not recoverable as metallic zinc. The remainder of the zinc, which finds its way into the precious-metal-bearing crust, is recoverable and naturally engages the operators' most exacting attention. Careful elimination of the impurities in base bullion has enabled the refiner to produce a zinc crust better adapted to retorting, which reflects favorably in the zinc recovery; and to produce a richer crust, thereby lowering the zincking cost, as the increased efficiency of the zinc results in less of it being in circulation. It is obvious that if the ratio of concentration be increased, a lessening of the amount of crust formed will ensue, throwing less work on the retorts and diminishing the amount of retort metal sent to the cupels, thus making an actual money saving in all these operations. In the effort to obtain a rich crust, the metallurgist has increased the heat to a considerable degree, upon the assumption that at the higher temperature the zinc-silver alloy could be squeezed free from the adhering lead. A further possibility for improvement suggested itself in the freezing-point curve of Prof. H. C. Carpenter, upon zinc and silver. Study of this curve disclosed the existence of a definite chemical compound, . Zn3Ag2, with a freezing point of 665° C., a promising compound for practical application.

Jan 2, 1915

By W. R. Phibbs

THE blast furnace of the Columbia Steel Corpn., at Ironton; Utah, was put in blast April 30, 1924, and its operation has presented some interesting problems. The coke for the furnace is furnished by 33 Koppers Becker type ovens of 15 tons capacity each. The coal is shipped from the company's mine at Columbia, Utah, which is approximately 123 miles from Ironton, and is probably the highest volatile coal that is being coked for blast furnace use in this country. The analysis of the coal is: PER CENT. Moisture 3.90 Volatile 39.00 Fixed carbon 51.10 Ash.... 6.00 Sulfur : 1.07 The analysis of the coke is: PER CENT. Volatile 0.55 Fixed carbon :...:.::: :..:.:: 89.70 Ash 9.75 Sulfur 1.05

Jan 1, 1928

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

The austenite solidus of the iron-carbon system has been determined using a series of diffusion couples, each of which consisted of a specimen of austenite held in contact with a melt saturated with austenite. After the equilibrium distribution of carbon had been established by diffusion at a specified temperature, i.e. the austenite specimen had become austenite of the solidus conzposition, the diffusion couple was cooled, sectioned and anazlyzed for carbon. The solidus was found to be a straight line: A revised iron-carbon temperature-composition diagram is presented, COMPOSITION has a marked effect on the temperature at which austenite begins to melt and the austenite solidus of the iron-carbon system describing this effect has been the subject of many investigations.1-10 The significant results of these investigations are presented in Fig. 1. The experimental methods and purity of the materials used in them are summarized in Table I. In plotting the data in Fig. 1 no attempt has been made to convert these results to the International Temperature Scale of 1948," except for the data of Adcock,5 as this conversion would do little to reduce the uncertainty that exists as to the position and shape of the solidus. A point of major concern in evaluating these data is that the alloys studied, except those used by Adcock, were not binary alloys of iron and carbon, Table I. Also, it would appear that several of the methods did not permit equilibrium to be established through the system being studied. All that can be said for the results of these investigations is that they indicate only approximately the location of the solidus with the uncertainty as to its location at 1 pct C being approximately 100°C. The current investigation was undertaken to provide reliable data by which the austenite solidus could be established. It was hoped that information on the liquidus also could be developed at the same time, but experimental limitations prevented this as austenite segregated from the liquid on cooling. After a careful study of possible experimental methods and extensive laboratory tests, it was decided that the use of a series of austenite-liquid diffusion couples would provide the most reliable results. This paper describes the method and its results and also includes a complete iron-carbon temperature-composition diagram based on what are considered to be the best available data. EXPERTMENTAL METHOD The diffusion couple used for this investigation consisted of a small cylindrical pellet of austenite held in contact, at a specified temperature, with a melt saturated with austenite. The composition of the cylindrical austenite pellet was chosen to be approximately 0.1 wt pct C less than the estimated

Jan 1, 1962

By M. E. Shank, J. Wulff

In view of the current interest in magnetic materials having rectangular hysteresis loops, as for example those obtained with the grain oriented 50 nickel 50 iron alloys,t we wish to call attention again to the results obtainable with the perminvar (Co-Ni-Fe) alloys heat treated in a magnetic field. Data taken from direct current measurements made prior to and during World War II give the typical values shown below for two of the perrninvar alloys. Fig 1 and 2 show- the hysteresis loops for these samples. The first sample above consisted of small rings punched from 0.014 in. sheet stock. These rings were heat treated at 1000°C for one hour in a hydrogen atmosphere and then cooled with the furnace to 750°C at which point they were subjected to a magnetic field of 15 oersteds maintained during cooling to room telmperature. The molybdenum perminvar sample consisted of a spirally wound core of 0.001 in. tape. The heat treatment was the same except that box annealing methods were used and no hydrogen atmosphere was employed. Even better properties might be expected using hydrogen. The heat treating temperatures and cooling rates are not critical. Rectangular hysteresis loops produced in other perminvar alloys by heat treatment in a magnetic field were described earlier.',? Properties similar to those described above are realized in perminvars manufactured by conventional methods. Drastic cold working which in practice limits the final thickness and is gen- erally expensive may thus be avoided. This information may be of interest to those concerned with magnetic alloys and the development of contact rectifiers, magnetic amplifiers and so on.

Jan 1, 1950

By A. E. Jenkins, A. Jostsons

Isothermal sections of the Ti-0-H phase diagvam at 600°, 700°, and 800°C have been constructed from equilibrium hydrogen pressure measurements over a range of Ti-0-H alloys containing up to 34 at. pct 0. Oxygen reduces the hydrogen solubility at fixed hydrogen pressure but increases the terminal solubility in the a solid solutions at the a/(a + P) phase boundary. Metal-lographic studies of alloys annealed below the eutectoid temperature show that oxygen also increases the ter-ninal solubility of hydrogen in the a solid solution in equilibrium with the hydride phase. The effect of oxygen on hydrogen solubility is discussed in terms of the electronic and geometric structure of interstitial solid solutions. THE isothermal solubility of hydrogen in a Ti-0 alloys at 800°C has been measured by Hepworth and ~chuhmann' who subsequently used ternary Gibbs-Duhem integrations to calculate oxygen activities in binary Ti-0 alloys. The present study aims to extend Hepworth and Schuhmann's measurements to alloys richer in oxygen and to a range of temperatures. This paper presents the results of hydrogen equilibrium pressure/concentration measurements in Ti-0 alloys as well as observations on the effect of oxygen on the terminal solubility of hydrogen in a titanium. The thermodynamic properties of binary Ti-0 alloys, derived from these measurements, will be published separately.' EXPERIMENTAL METHODS Specimen Preparation. Ti-0 alloys were prepared from iodide-refined titanium and titanium dioxide obtained by hydrolysis of redistilled titanium tetrachlo- ride. Specimens containing up to 16 at. pct 0 were prepared by electromagnetic levitation3 whereas a conventional tungsten arc furnace with a water-cooled copper hearth was used to melt oxygen-rich alloys. The specimen homogeneity was indicated by the constancy of lattice parameters of samples from various parts of the ingot as well as by the sharpness of the reflections on X-ray powder patterns. Oxygen-rich specimens in the composition range (20 to 34 at. pct), where ordering has been ~bserved,~ were annealed for 300 hr at 600°C prior to use in hydrogen solubility measurements. Apparatus. The hydrogen pressure/concentration measurements were made with a modified Sieverts apparatus shown diagrammatically in Fig. 1. Specimens were placed in a clear silica tube and impurity pickup by direct reaction with silica was prevented by lining the heated end of the silica tube with thin molybdenum sheet. A double silica tube was required to eliminate loss of hydrogen by diffusion through silica at high temperatures and high hydrogen pressures, the space between the tubes being maintained at a hydrogen pressure equal to that above the specimen. Hydrogen was purified by diffusion through a Ag-Pd tube.= Hydrogen pressures were measured with a mercury McLeod gage in the range 0.001 to 4 Torr

Jan 1, 1968

By F. E. Harris

It has been said that carbon is "ubiquitous" with reference to iron alloys. Certainly at temperatures where carbon and iron form the solid solution, austenite, it may be readily added to, or removed from, steel surfaces. Differences in concentration potential are the sole requirements for carbon flow. To measure the rate of carbon flow, a proportionality factor, D, is arbitrarily expressed in units of (length)2 X (time)-'. If the term used for carbon concentration is weight Pet C, as is customary, then a factor must be found, changing this term to One of weight Per unit volume when the diffusion coeficient, D, is used in flow formulae. The determination of D values for carbon is complicated since D varies with the concentration itself. The Matano method has often been employed for systems involving a variant D. This method expresses all evaluation of unsteady flow whereby D is given a relationship with the numerical value of C-x slopes. The author contends that this solution is incorrect, except when D is invariant. The primary purpose of this paper is to support this contention. Here diffusion is controlled under two conditions of flow. The first part deals with the steady state; the second part considers unsteady flow under definite restrictions. Beginning with the fundamental concept, the development is continued until equations for C-x curves are obtained. The solution is then subjected to experimental data. It is realized that a great amount of reliable data is required for a rigorous proof. KO such research is claimed. Instead an attempt is made to set forth the physical significance of the diffusion mechanism, and particularly to express the factors which influence the flow of carbon in austenite. Of equal significance is the implication that gaseous media may be employed with reasonable accuracy in making these determinations. The Steady State Diffusion of Carbon in Au~tenite The fundamental experiment defining diffusion in solid metals may be readily performed for carbon in gamma iron.' For this experiment a thin plate of medium carbon steel is chosen. The surfaces of this plate may be taken as two parallel planes which may be considered infinite for points well in the Center of the planes. These two planes are held at different concentrations of carbon at a constant temperature. This temperature, 1700°F for example, is one where the single phase: carbon in solution with gamma iron, exists. When these conditions are held for a sufficient time the concentration of carbon of the different points of the solid ment down towards its steady state value. At points well removed from the ends, the concentration will remain the Same along planes parallel to the surfaces of the plate.

Jan 1, 1948