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By R. V. Ramani, T. V. Falkie, T. E. Wilson

In order to increase the efficiency of underground coal operations, it is necessary to understand not only the operating system in detail, but the interrelationships between system components and the operating environment. With such an understanding comes more exact application of simulation and other operations-research techniques to plan and operate mining systems. One aspect of the coal-winning system in need of better definition, namely, the performance of continuous miners, is dealt with in this paper. Detailed discussion of this research will be found in a report by the authors. Mining Rate The performance of continuous miners-that is, the rate at which miners can deliver coal from an underground face to the outby transportation system-is dependent upon the geometric and geological conditions of mining, the characteristics of the mining machinery, and the skill of the machine operators. In order to predict mining performance, it is necessary first to identify these factors, secondly to devise a data-collection technique, and lastly, to select a method of data analysis for drawing meaningful conclusions. Factors Affecting Mining Rate: The factors that affect the mining rate can be conveniently grouped in the following four categories: Geological Factors-The natural conditions such as seam thickness, hardness, and cleavage. Geometrical Factors-The height and width of the entries and the angle of drivage with respect to the main entries. Machine Factors-The mechanical characteristics and physical dimensions of the machine, condition of the machine, condition of the bits, and related items. Other Factors-Operator efficiency, size consist of cutter product, etc. A classification such as given here is not rigid; some of the factors can be included in more than one of the categories and some can be combined as ratios. Data Collection The empirical nature of this investigation required measurements of variables under operating conditions in underground coal mines. A majority of the variables measured were continuous over a specific range of values; for example, the "width ratio" varied in practice from 0.25 to 1.00. "Dummy" values were assigned to certain operational variables in order that the variables would have numerical expression, i.e.: [ ] Data Analysis The method of analysis was to test a large model containing potentially significant variables and then reduce the model to one containing only the essential significant variables. The procedure of "scanning" a large proposed model and subsequently condensing the model consisted of two cycles of the same series of computational procedures. Correlation analysis, factor analysis, and regression analysis were the three statistical procedures that were used to derive the rate-generating equation. Correlation and Regression Analysis: Multiple linear correlation coefficients between all of the variables were calculated using the Pearson product moment formula along with the statistical significance of the correlation

Jan 1, 1975

By C. R. Sandberg, L. S. Gournay, R. F. Sippel

The effect of fluid-flow rate and fluid viscosity on oil-water relative permeability determinations was studied using the "dynamic flow technique." In this work relative per-nleability curves were obtained for homogeneous small core .samples from several sandstorle outcrop form-utions. Radio-tracers were used for the determination of fluid saturation and for the detection of saturation gradients. Cobalt-60 in the form of cobaltous chloride was used as a water-phase tracer in some of the experiments. Iodine-131 in the form of iodobenzene and Mercury-20-3 in the form of mercury diphenyl were used as oil-phase tracers in other experiments. Flow rates for each phase were varied within a range of 2.5 to 140.6 ml/hr. Oil-phase vis-cosities under flowing condition,> were varied from 0.398 to 1.683 cp. The relative permbilities ob-tained were found to he solely a function of saturation and independent of flow rare, provided there was no .Saturation gradient induced in the core sample by "boundary effect." Even though equilibrium with re-sped to flowing conditions was obtained at the lower flow rates, where a saturation gradient exists, this equilibrium is of a "contingent"-type rather than the "steady-state" equi-librium implicit in the relative per-meability concept. The only effect of increasing the oil or non-wetting phase viscosity was to decrease the flow rate required for the elimina-tion of the boundary effect. Fairly good agreement between experimentally determined and calculated values of the boundary effect was obtained when the non-wet-ring oil phase was the only Flowing phase. INTRODUCTION In the characterization of reservoir rock, as well as in the solution of reservoir production problems, it is most desirable to have reliablc rela-tive permeability measurements for the rock and fluids of interest. Many techniques have been developed for the laboratory determination of the relative permeability of both large and small core samples. In varying degree, difficulties attend the use of all of the methods. Each of the methods requires the metered flow of fluids of known viscosity through the core sample under conditions wherein the pressure drop in the individual flowing phases can be measured or closely approximated. Since the relative permeability is a function of the saturation and distribution of the flowing fluids, some means of obtaining such information is also required. The laboratory determination of the relative permeability of a sample should give the same relative permeability saturation relationship that would exist if the sample were in place in the oil reservoir. The attainment of this objective is complicated by the fact that the use of small core samples for laboratory measurements is usually necessary. As a result, errors in measuring the relative permeability arise from boundary effects at either the fluid input or output ends of the sample; no significant boundary effect is anticipated at the sides of the sample normal to direction of fluid flow. At the input end of the sample a boundary effect exists if the flow fluids are not com- mingled as they would be in the reservoir. At the output end of the sample a boundary effect exists as a result of discontinuity of the capillary properties of the system. Here the flowing fluids leave the small flow channels and enter a collecting system having much enlarged flow channels. Thus, there is a tendency for the wetting phase to be retained by the core sample because of the attraction of the core sample for the wetting fluid. No reference is made to these boundary effects in either Darcy's equation or in the relative permeability concept. As a consequence the saturation effect peculiar to the input end of the core sample may cause an error in the effective permeability measurement, since some portion of the core sample must be utilized for commingling of the flow fluids. At the output portion of the core sample a saturation gradient or a saturation change along the axis of flow results. Since relative permeability is a function of fluid saturation, this saturation gradient may cause a variable permeability measurement, especially since extent and character of the saturation gradient can vary with fluid-flow rate. The most convenient method of minimizing the boundary effect, especially at the output end of the sample, is to flow the fluids of interest through the core sample at such high rates that the capillary forces arc insignificant as compared to the viscous forces involved in the fluid flow. Since recent work of a preliminary nature has indicated that fluid dispersion in the porous medium increases with the flow rate, the high flow minimizes the boundary effect at the input end of the core sample by enhancing the mixing of the fluids.

By Romeo Calderón

El presente trabajo describe los trabajados realizados en la Compañía minera Huarón con el objetivo de realizar la explotación de vetas muy angostas y sinuosas de potencias inferiores a 1.20 m. de un modo seguro, eficiente y económico, donde fue necesario resolver el problema de carguío y acarreo en tajeos inferiores a 1.20 m. empleando equipo LHD de 0.80 m. de ancho, fabricado especialmente para este fin.

Nov 1, 1982

By R. C. Fernandes, F. L. Santos

Aluminum alloys in particular, have certain limitations when subjected to welding process. This is mainly present because aluminum alloys have high thermal conductivity, high contraction in solidification and high hydrogen solubility. Taking this into account, the FSW process has great potential for this application, since it is autogenous, held without metal melting and without the use of slags or shielding gases. From this concept, the aim of this study is to evaluate the joining of thin sheets of aluminum alloy 3105 H26 with 0.7 mm of thickness. To performing of the tests, some parameters were analyzed, such as: tool penetration in the sheets, attack angle, the type of welding tool and penetration control mode (position or force). The results indicated that the force control mode is most suitable for thin sheets, and the transient state at the beginning of welding was the most critical part to control the welding quality.

Jan 1, 2015

By M. B. Ramachandra Roa

This paper records the results of the earth resistivity surveys made in the Godavari River in connection with the Ramapadasagar project. After describing the topographical and geological features of the area, the results of the investigation at the several sites have been mentioned. Further, a detailed account has been given of the resistivity methods adopted, the apparatus used and the interpretation of the curves. The resistivity measurements carried out over the water course have been specially outlined, and a review of the verification of the electrical indications by drilling in a number of cases, has also been presented. Introduction The Government of Madras has under consideration the Ramapadasagar project which is estimated to cost some Rs.660,-000,000 (about two hundred million dollars). The most essential feature of this project is the construction of a high dam across the Godavari near Polavaram for impounding the waters of this great river of South India, whose maximum discharge is 2 million cu secs in flood time. It is estimated that when the proposed reservoir is constructed, about one million tons of rice could be produced annually under irrigation. To those who have had any acquaintance at all with the recent distressing famine conditions which India has passed through and is still undergoing, the Lounteous effects which this project will bring about to the country in the future, are obvious. In the region of the proposed reservoir, the river flows for several miles through a hilly tract, hemmed in between flanks of hard, solid rock; but the river bed is mostly sandy. A few bore holes put down in this sandy bed touched rock at a depth of 180 to 200 ft. The river bed is about jo ft above the mean sea level (m.s.l.) and the bedrock was found at —125 to —160 ft m.s.l. The crest of the dam is proposed at +162 ft m.s.l. The proposed dam mould therefore be about 120 to 130 ft above the river bed, and the foundations would have to reach down nearly zoo ft below the bed at the deepest part. A number of alternative sites were proposed for investigation, and it became necessary to quickly ascertain the bedrock topography at these sites. Dr. M. S. Krishnan,* who was consulted in the matter, furnished a detailed account of the geological features of the region and suggested a geophysical investigation which the writer carried out from February to April 1944, employing solely the electrical resistivity methods. The total length of the survey lines for the electrical measurements amounted to 62,600 ft and the number of resistivity determinations was about 2500. Altogether nine alignments for the dam were inten-

Jan 1, 1949

By William Johnson

IT is now recognized that several important types of reactions in metallic systems proceed by the formation of nuclei and the growth of these nuclei. The process of freezing is a simple example of this, as Tammann pointed out years ago.1 Tammann held that ' the rate, of freezing is determined by a rate of nucleation, expressed as the number of nuclei formed per unit volume of unfrozen liquid per second, and a rate of growth of these nuclei, expressed as the linear rate of radial growth in units of length per second. For isothermal freezing the conception is simple; for ordinary freezing, extending over a range of temperature, it is not as simple, for the values of the two constants must change with change in temperature. There is ample evidence that the postulated mechanism is correct even though a quantitative derivation of the rate of isothermal or of ordinary freezing in terms of the two constants has been lacking. In recent years other reactions have been found to proceed in a similar fashion. It has been well established, particularly by Bain,2-8 that. the formation of pearlite from the eutectoid decomposition of the solid solu-tion austenite proceeds in such a way, and Polanyi and Schmid, Tammann and Crone, Karnop and Sachs, and others9-11 have shown that the process of recrystallization proceeds in a similar way. Isothermal reaction rates have been determined for eutectoid decom-position by a number of investigators. Bain's2-8 work on the formation of pearlite from austenite is especially valuable in this respect-the type of isothermal reaction curve obtained, as illustrated in Fig. 13, showed an initial slow rate, accelerating to an intermediate maximum rate which then decelerated to the completion of the reaction; similar curves have been obtained by Wever and his collaborators.12 Other eutectoid decompositions show similar behavior: for example, the decomposition of the beta eutectoid in the copper-aluminum system, studied by Smith

Jan 1, 1939

By D. K. Dysinger

The U.S. Bureau of Mines investigated leaching of chalcopyrite with sulfuric acid-oxygen under conditions anticipated during in situ leaching. A central composite experimental design was chosen to study oxygen pressures of 150, 300, and 450 psi, leach temperatures of 35?, 65°, and 95° C, oxygen-to-chalcopyrite mass ratios of 0.5, 1.0, and 1.5, leach times of 8, 16, and 24 hours, initial acid strengths of 0.6, 1.2, and 1.8 g H2SO4/g chalcopyrite and pyrite to chalcopyrite mass ratios of 0, 1, and 2. The leaching kinetics were consistent with the shrinking core model. A quadratic response surface model was used to determine linear and interaction effects of the design factors on rate constants from Arrhenius correlations.

Jan 1, 1993

By W. Bleloch

Published in the Journal, September 1970, and presented at a colloquium on 'Future of the Steel Industry', 17th March, 1971. Errata (a) The final sentence in the penultimate paragraph, left hand column p. 34 of the text should read: 'In the hot regions of the bosh and stack the C+CO2=2CO reaction proceeds to CO from coke carbon and carbon dioxide generated by reduction of iron oxides by CO (the so-called solution loss of carbon)'. The italicised words have been omitted in the text. (b) Temperature in Fig. 3 is K not C. (c) In Fig. 9, connection from top plate of column 10 to heat exchanger 9 has been omitted. DISCUSSION J. B. BEEDON AND C. J. JONKER* Dr Bleloch's paper has outlined the advantages of recycling stack-gas of low nitrogen content in the blast furnace. In the first instance it would appear to be extremely beneficial in controlling the hearth temperature and allowing a 100 per cent oxygen-blast to be used. On a second point however we have to disagree. It is claimed that heat is liberated in the combustion zones by the oxidation of CO to CO2 near the tuyeres and in the subsequent reduction of the CO2 by CO. The author has hypothesized as follows, and we quote: 'The C+CO2=2 CO reaction in the outer combustion zone at about 1 700°C is no longer endothermic due to loss of stability of CO2 and its consequent dissociation into CO and free oxygen.' This statement requires closer examination. If we consider the individual events occurring with the CO in the recycled topgas, with the oxygen in the blast and with the coke in the burden, as done by Dr Bleloch, the following heat considerations emerge. All heats of reaction are calculated from the enthalpy values of each reactant and product, as well as the temperature dependence of their molar heat capacities. (a) At the tuyeres: CO+1/2 O2-+CO2 . . . . . (1) CO, CO2 at 500°C; O2 at 25°C. ?H reaction = -65 000 cals/mole CO The reaction (1) is exothermic. (b) In the outer combustion zone: CO2+C?2 CO . . . . . . . . (2) C, CO at 1 700°C; CO2 at 500 0C. ?H reaction = -56 000 cals/mole CO Reaction (2) is endothermic. The overall heat gain of reactions (1) and (2) is ?H=+56 000 - 65 000= -9000 cals/mole CO i.e. the overall reaction is slightly exothermic, the amount of heat liberated is however smaller than suggested by Dr Bleloch. (c) The dissociation CO2+CO+1/2 O2 . . . . . (3) is a highly endothermic reaction at 1 700 0C, requiring 82 000 cals/mole CO2 to proceed to completion. Furthermore, this reaction (3) is energetically not favoured to proceed, as can be observed from the free energy-temperature relationship of figure (3), which favours the formation of CO2 at 1 700 0C. Hence direct dissociation of CO2 at 1 700 0C appears to be unlikely.* The concept of recycling topgas is however still intriguing from many other points of view. Apart from providing a very efficient method of hearth temperature control, it will create a much higher CO partial pressure in the stack. Whether the rate of indirect reduction in the stack will be proportional to this partial pressure or not is un-

Jan 9, 1970

By D. D. Porter, C. Fairhurst

Crack propagation in the region of a statically pressurized borehole is investigated to determine a role of the sustained borehole pressure following detonation in a blast. The case of a single-hole bench blast is reduced to a plate model, which is considered both theoretically and experimentally. Based on the principle of least work, it is hypothesized that the path of any crack in the plate will coincide with one of a family of maximum principal stress trajectories. These trajectories were computed, and critical experiments in glass, designed to test the effects of controlled crack origin and of changed trajectories from different loading configurations, confirm this hypothesis. It is concluded that under ideal conditions the crack path can be predicted and that cracks can be produced in the absence of either high-amplitude stresses or stress waves. Energy considerations for crack extension are discussed, and, based on the strain energy distribution, a relationship between hole burdens and spacings is revealed, a critical burden is demonstrated, and a maximum crater width is shown to exist.

Jan 1, 1971

By Adrian E. Scheidegger

"AbstractThe possibilities of deriving pertinent information about fractures in an oil pay from data obtained by core analysis are investigated. It is shown that it is possible to obtain an estimate of the fractured area per unit volume of the pay, and that the size of the fractures can be estimated if their shape is known. A suggestion of a routine procedure for the analysis of fractures is given.1.-IntroductionMany oil fields are producing essentially from cracks or fractures. Where this is the case, it is important to be able to obtain a knowledge of the size and distribution of those fractures in the oil pay. This knowledge has to be derived from the analysis of cores taken from the fields, as it is generally impossible to follow a fracture through the pay by direct means. The necessity of using statistical methods to extrapolate the meagre information obtained from the cores of the wells is therefore indicated.It is known that the fractures are much bigger than the diameter of the cores; thus, if they strike a core, the latter will generally fall into two pieces. The angle of the fracture with the vertical can be measured and, if oriented cores are taken, the exact position of the surface element representing the intersection of the fracture with the drill stem can be determined. Sometimes the edge of a fracture can be seen in a core. The number of •Cores that show such an edge can be noted. Of course, one has to be careful to distinguish between original fractures in the pay and fractures in the core caused by drilling operations. Only the former are relevant."

Jan 1, 1955

By M. D. Amirova

Cyanide-free technology of complex copper-lead ores flotation may be improved through enlarged range of pH values, enhanced copper recovery into copper concentrates due to additional recovery of secondary copper sulfides, as well as through enhanced efficiency of lead sulfides depression in process of new flotation modifiers-based selective separation. Study of the effects of flotation modifier (of metal nature) on minerals surface conditions proved that the xanthate is practically not adsorbed on the galenite surfaces due to minerals hydrophilization. Joint effects of sodium sulfite and modifier enhance process conditions for intensive galenite depression and at the same time for effective chalcopyrite and chalcosine flotation within a large pH values range (from pH=8 to pH=10). Identified mechanisms carry inference that proposed chemical reagent treating method is very promising for selective copper-lead concentrates separation. Potential use of carbon-containing materials as zinc flotation modifier to enhancing zinc recovery in processes of lead-zinc ores treatment has been studied. In our flotation tests we used Shalkiya (South Kazakhstan) lead-zinc ores containing such impurities as carbon shales, which presence impedes the process of saleable concentrates production and gives rise to excessive consumption of flotation agents due to the xanthate adsorption on the carbon. Lead and zinc concentrates were produced by process stages as follows: ores milled to 95% Cl. -0.074 +0; lead and zinc roughing flotation and further recleaner and testing operations. Test flotation in open process cycle resulted in enhancing zinc recovery into zinc concentrates by 21.1% and increasing zinc content in zinc concentrates by 3.96% that evidences promising potentialities for use of carbon-containing products as additional zinc flotation modifier. Works were carried out under National Program 2003~2005 of fundamental researches ?Physical and Chemical Mechanisms of Interactions in Multicomponent Solid and Liquid Systems Specific for Integrated Processing of Complex Metal-Containing Minerals and Technogenic Raw Materials? and contractual Agreement 2005 Optimization of Production and Technology of Shalkiya Lead-Zinc Ores Processing at Kentau Dressing Works.

Jan 1, 2014

By Nelson Hogg

"THE NOR-ACME gold mine is located close to the north shore of Snow Lake, at 54°53' north latitude and 100°03' west longitude. It is about 75 air miles east of Flin Flon, and 36 miles by road from Wekusko at Mile 81 from The Pas on the Hudson Bay Railway.The claims which contain the Nor-Acme orebodies were staked in 1927 by C. R. Parres, who, with his sons, held the ground until 1938 when Nor-Acme Mines Limited was incorporated. In 194 l, on the recommendation of F. Ebbutt (1), this property was optioned by the Howe Sound Exploration Company, Ltd. A program of 50,000 feet of diamond drilling resulted in the outlining of two orebodies containing an estimated 5,000,000 tons with an average grade of 0.15 ounces per ton to a depth of 1,000 feet.A period of inactivity during the war years was followed by the construction of a mining plant capable of treating 2,000 tons of ore per day. Milling started in March 1949, and to the end of 1954 has resulted in the production of 383,793 ounces of gold and 32,906 ounces of silver from 3,331,403 tons of ore.General GeologyThe general geology of the Snow Lake area is described by J. M. Harrison (2), and will not be discussed here except insofar as it affects the Nor-Acme orebodies. The orebodies occur in rocks of Precambrian age that have been classified by Harrison as the Snow group, comprising meta-morphosed sediments interbedded with acid and basic volcanic rocks. The volcanic rocks include pyroclastic types which are unique in the region, a fact which led to their classification in the Snow group rather than the more widespread Missi group that generally occupies the same stratigraphic position above the Amisk group (Figure 1)."

Jan 1, 1949

By R. E. Head, E. L. Tucker

Previous investigations of E. L. Tucker and R. E. Head' related in particular to the effect of cyanogen compounds on galena, sphalerite, and pyrite, and their behavior in the presence of such compounds. The present contribution deals with the floatability of the copper minerals and of pyrite. All experiments were performed on minus 200-mesh material, the method of preparation being the same as that described in the previous article. Flotation tests were made in a small mechanically agitated machine of 50-gm. capacity designed in this laboratory by Gates and Jacobsen.2 General Naval Stores pine oil No. 5 and potassium xanthate were used in constant amount in all of the experiments; these agents were selected because of their present wide use in the flotation of copper minerals. Time additions were varied to secure four final hydrogen ion concentrations, namely, neutral, 0.0005 per cent. CaO, 0.003 per cent. CaO, and 0.02 per cent. CaO. The variation in lime addition was introduced to include the range of alkalinities employed in actual flotation practice. The minerals employed were the purest obtainable. Their analyses are shown in the following tabulation: Table 1.—Analyses of Minerals Employed in Experiments mineral Cu Fe Cao S MgO Insol. Chalcocite .............. 77 02 0.49 0.29 21.70 0.08 0.28 Chalcopyrite............. 34.50 29.20 0.23 34.10 0.07 1.42 Bornite................. 64.30 9.30 0.12 23.70 0.10 1.95 Pyrite....................... 36.90 1.12 49.70 .... 1.51

Jan 1, 1926

By R Sharpe, M D. Hannington, K Perrin, K Simpson, S Petersen, H Gibson, N Augustin, K Lackschewitz, T Monecke

Semi-massive to massive sulfides were drilled in a shallow-water (630 m) hydrothermal system in an island arc volcanic setting at the Palinuro volcanic complex in the Tyrrhenian Sea,Italy. Overall 12.7 m of sulfide minerlisation were drilled in a sediment-filled depression in a water depth of 630 - 650 m using the lander-type Rockdrill 1 drill rig of the British Geological Survey. The longest drill core recovered consists of 4.9 m of continues semi-massive to massive sulfides + sulfates with abundant late native sulfur overprint. Metal enrichment at the top of the deposit is evident in some cores with polymetallic (Zn, Pb, Sb, As, Ag) sulfides overlying more massive and dense pyritic ore. The massive sulfide mineralisation at the Palinuro volcanic complex contains a number of unusual minerals, including enargitefamatinite, tennantite-tetrahedrite, stibnite, bismuthinite and Ag-sulfosalts, that are not commonly encountered in mid-ocean ridge massive sulfides. In analogy to epithermal deposits forming on land, the occurrence of these minerals and the abundance of native sulfur suggest an intermediate to high sulfidation state for the hydrothermal fluids during deposition, implying that the mineralising fluids were acidic and oxidised rather than near-neutral and reduced as those forming typical base metal-rich massive sulfides along mid-ocean ridges. Oxidised conditions during sulfide deposition are likely related to the presence of magmatic volatiles in the mineralising fluids that were derived from a degassing magma chamber below Palinuro volcanic complex. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

Innovative mining technology came to Texas in the form of bucket wheel excavator/cross-pit spreader systems. Texas Utilities Mining Company put the first system to work at its Big Brown Mine in December 1985. The second such system was put into operation at the Monticello Mine in February 1991. The cross-pit spreader systems are mobile, electrically powered, excavation and conveyor systems, the principal components of which include bucket wheel excavators (BVE) and an across-the-pit conveyor (spreader). These crawler mounted machines operate as a unit; the BVE's excavate overburden, feed it via conveyors to the spreader which in turn conveys the material across the open pit and onto the developing spoil bank. The system at the Big Brown Mine is composed of 2 BVE's and an across-the-pit conveyor while the Monticello system is made up of 1 BVE and a spreader. The BVE's prestrip overburden preparing a dragline bench for the final removal of overburden. Numerous evaluations, including lignite production requirements, economics, overburden characteristics, rehandle reduction, spoil stability, and the compatibility with dragline operations, led to the selection of the cross-pit spreader system at the Big Brown Mine. The system has proven itself as a viable and economical means of prestripping. The system's success at the Big Brown Mine led to the development of a second such system at Monticello. The advent of the cross-pit spreader system is viewed by Texas Utilities Mining Company as a viable solution to recovering deeper lignite reserves in a safe and economical manner.

Jan 1, 1993

By Yingchang Tsenshan Wang

UUIN L&SS 1» Paqb I. Introduction........................................................658 1. Subject and Scope...............................................658 2. Acknowledgments...............................................659 3. Review of Previous Work........................................659 Field Data...................................................659 Experiment.a1 Data............................................662 4. Plan of Present Investigation.....................................662 Method of General Procedure...................................663 I1. Experimental Work..................................................663 A. The Solution of Sphalerite..............................:........663 1. The Solvent Effect of Iron Sulphates upon Sphalerite...........663 2. The Solubility of Sphalerite in Salt Solutions of Silver, Copper and Lead...............................................668 B. Formation of Zinc Carbonates....................................674 3. The Reactions of Carbonates and Bicarbonates With Solutions of Zinc Salts............................................674 4. The Reaction of Zinc.Sulphate Solution With Limestones.......684 C. Peculiar Conditions Affectitig the Formation of Zinc Silicate (calamine) and Zinc Carbonate (smithsonite)..........................686 5a. The Effect of Carbon Dioxide Upon the Basic Silicate and the Carbonates of Zinc in Water, and Its Bearing Upon the Conditions of Theii Precipitation..............................686 5b. The Reactions of Solutions of Soluble Silicate With calamine and Smithsonite in Solution in Presence of Carbon Dioxide..689 6. The Reactions of a Mixture of Hydroxide and Silicate of Sodium with a Dilute Solution of Zinc Sulphate...................691 D. High-Temperature Methods.....................................692 7a. The Influence of Temperature on the Formation of Calamine..692 7b. Possible Effect of Heat on Calamine and Srnithsonite.........697 E. Summary of the Experimental Work..............................698 III. Petrographic Work....................................................700 1. The Occurrence of Sphalerite in Limestones or in Cherts............701 Summary of the Blende in Limestones and in Cherts.............7432 2. The Partially Altered Sphalerite and the Oxidation Products........702 a. Smithsonite with Blende....................................702 b. Calamine with Blende......................................703 c. Smithsonite and Calamine..................................703 d. Summary on the Partially Altered Sphalerite and Its Oxidation Products..............................................704 IV. Concl~~siom ........................................................-705 V. Microphotographs and Photographs with Their Explanations.............705

Jan 1, 1916

By Mohamed Ahmed, A. Kawy

"Smelting of scrap copper and residual anodes and cathodes carried out in a reverberatory type furnace. In this, deoxidation process is carried out by wood, which acts as a resource of reduction gases such carbon monoxide, hydrogen and methane. Use of wood causes the formation of soot pollutants and efficiency of oxygen removal from copper is low leading to added costs in removing contaminants. This expensive problem was solved by using of reformed natural gas as a source of reduction gases (CO+ H2).IntroductionThree reverberatory furnaces were used for smelting of scrap copper and residual anodes and cathodes. Each furnace had a 7tpd capacity and was operated at 1183 °C.In this furnace, Step1-compressed air supplied by tubes from the side of the furnace to remove sulfur from copper matte by oxidation .The copper is also oxidized to copper oxide .[1]Step 2- copper from matte is deoxidized by a reductant. Typically deoxidation process is carried out using wood as a resource of carbon monoxide, hydrogen and methane which are the reduction gases. Use of wood causes the following:1- Forms soot pollutants2- Oxygen removal efficiency from copper is low; more contamination in copper matte increased energy in deoxidation3-the process is highly expensive.In the recent trends, this problem has been solved by using reformed natural gas as a source of reduction gases (CO+ H) .This results in 1-Reduced pollution during smelting.2- High efficiency in the removal of oxygen from copper to produce oxygen free copper. The surface of copper produced from this method is smooth which helps in forming and machining.3- Low cost and natural gas is more readily available in Egypt than wood."

Jan 1, 2010

By Jos. R. Guiteras

This paper is one of a series describing; mining and milling methods and costs being published by the Bureau of Mines. It deals with the mineral resources of western South Dakota and describes the mining and milling of tantalite and associated amblygonite by the Black Hills Tin Co. and the Fansteel Mining Corporation. ACKNOWLEDMENTS Acknowledgment is made to Earl C. Schultz and Arthur I. Johnson, respectively superintendent and engineer for both the Black Hills Tin Co. and the Fansteel Mining Corporation, who contributed the information on mining and milling operations.

Jan 1, 1939

By A. L. Engel

The sample of ore on which the work described in this paper was done came from Mina Oriente, Carrizal Bajo, Provincia de Atacama, Chile, South America, and was sent at the request of the Chil.ean Government through the Foreign Minerals Division of the Bureau of Mines. This ore had been tested locally for treatment by flotation and cyanidation without satisfactory results. An additional difficulty was the absence of water near the ore deposits, so that in any treatment method considered the water requirements would have to be very low. It was desired to develop a practical method of recovering the gold and, if possible, the copper in the area. No data of previous investigations were made available. The sample received was mostly quartz, highly brecciated, with limonite and hematite in the fractures. Copper occurred as malachite and azurite, also in the fracture s and to a slight extent as a stain in the quartz. Some fine-grained pyrite with a little arsenopyrite occurred within the quartz. An occasional grain of chalcopyrite was observed. No free gold was seen during examinations of the ore, but amalgamation indicated that some was present.

Jan 1, 1949

By D. A. Stevenson, T. Alden, J. Wulff

A portion of the liquidus curve has been determined for the binary alloy systems Ni-Pb and Cr-Pb. The solubility of nickel is 0.53 atomic pet at 372° and 18.63 atomic pet at 1200°C. Chromium shows low solubility, 0.634 atomic pet at 1210°C. Molybdenum and tungsten were also studied and found insoluble in lead, less than 0.005 atomic pet at 1200°C. INCREASED use of liquid metals of low melting X point for heat transfer, coating, joining, and other purposes has renewed interest in the solubility of structural metals in these liquids. A study of Hansen1 and current literature indicates that few liquidus curves at the low melting end of the binary diagrams have been accurately delineated. This statement applies particularly to the binaries of lead. The present paper is limited to nickel, chromium, tungsten, and molybdenum in lead. In early studies2, 3 of the lead end of the Pb-Ni system, a monotectic at 1340°C was established. Tammann and Oelsen' determined the solid solubility of nickel in lead at 20°C to be 0.023 wt pet. Recently Pelzel5 determined the liquidus curve from the eutectic temperature of 327° up to 727°C using a segregation method. In the present paper this part of the curve has been checked and extended to 1244°C. The Pb-Cr system was first studied by Hindrichs.6 He pointed out the existence of a monotectic at 1470°C and indicated a tentative liquidus. Recent corrosion studies of Fe-Cr alloys in lead suggest that chromium is more soluble than iron in lead.7-8 The solubility of tungsten in lead according to Inouye8 is about 30 wt pet at 1200°C. Appreciable solubility of molybdenum in lead might therefore be expected. Experimental Various experimental techniques have been employed in the determination of solubility in liquid metals. For low solubility, thermal analysis is unsatisfactory. A segregation method was used by Pelzel3 in his study of the Pb-Ni system. In this procedure separation of liquid and solid is possible due to difference in density. In the technique of Kleppa10 a single piece of material is maintained in contact with the liquid metal in evacuated Vycor vials. After equilibration, solid and liquid are separated by tilting. Keck and Broder" measured the weight of a piece of the solid solute before and after immersion in a pure solvent bath; the weight loss was a measure of the solubility. All of the above procedures are time-consuming since they permit only one determination per run. Numerous samples for analysis may be taken from the melt in the method described by Gurinsky and CO-workers.10 The rate of extraction of samples is limited only by the time required for equilibration. In the present work, a modification of this method was employed. A 150-g charge of analytical reagent grade lead and the added metal* were contained in an Alun- dum crucible. It rested on firiely divided silica at the closed end of a 45 mm Vycor tube, 500 mm long. The top of the tube was provided with an inlet and

Jan 1, 1959