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By G. Cifuentes

The kinetics of the electrolytic oxidation of cyanide to cyanate on PbO2-coated stainless steel anodes have been studied by both experimental and theoretical means. The anodes were based on 316 steel and performed in a satisfactory fashion. The pH of the studied KCN solutions exhibited a constant value about 11. Values for all the kinetic parameters have been determined and a mechanism for the studied reaction is proposed.

Jan 1, 1999

Lime-enhanced carbothermic reduction may provide an alternative process for treating low grade chalcopyrite concentrates. To date, most research on lime-enhanced reduction has been on pure, synthetic sulfides. In this study, preliminary experiments were carried out on natural chalcopyrite using a thermal analysis system to assess the rate and extent of reaction at several temperatures and identify the major solid and gaseous reaction products. Calculations were performed to establish the thermodynamic limits of the reactions in the temperature range of interest in order to identify the potential conditions for processing chalcopyrite concentrate. The study found that finely ground chalcopyrite can be reduced carbothermically in the presence of lime at moderate temperatures and in a reasonable time to form metallic copper, with the sulphur reporting virtually entirely to calcium sulfide. At temperatures below about 750?770ºC calcium ferrite is the stable form of iron whereas at higher temperatures metallic iron is stable. Further work is required to demonstrate the reaction on a scale to obtain sufficient sample for evaluation of subsequent processing steps to remove the gangue material and iron products from the copper.

Jan 1, 2009

By Edgar A. Scholz

The purpose of this paper is to make a comparative cost analysis of domestic and foreign exploration projects which developed into mines during the 1960-1974 time period. A total of 18 mining companies, American and Canadian, were approached to solicit cost data on domestic and foreign exploration projects which developed into mines. Only 20 percent of the companies to which questionnaires were sent made data available. Several companies answered negatively, informing us that they would have difficulty in attempting to sort our costs. Some companies were usable to release cost details. It is comforting, however, to realize that some of the non-contributing companies expressed eagerness to hear the findings of this paper. Inasmuch as the data available on exploration expenditures is, in some cases, somewhat uncertain and that no two mining companies follow the same system of cost allocations, the results obtained in this analysis should he interpreted as trends of a general character.

Jan 1, 1976

By T. Cohen

Technological innovation in the minerals industry must be driven by the need to improve performance according to social, as well as environmental, safety, efficiency and production criteria. This paper outlines the possibilities and rationale for incorporating constructive technology assessment into technology research and development within the CSIRO Minerals Down Under National Research Flagship (MDU). The paper develops a process of Social License in Design that attempts to address the future social challenges and opportunities of a technology during development by utilising forecasting techniques and accounting for the perspectives and values of decision makers and likely stakeholders. Interviews with senior technologists and social scientists within MDU reveal the institutional context into which the Social License in Design process is to be situated and highlight key factors that may inhibit or enhance its uptake.

Jan 1, 2011

Development of Grindability Tests Based on Direct Measurement of Energy Nowadays, for the characterisation of the grindability different grindability indices - Bond-work index (Wi), Hardgrove Grindability Index (HGI) or Zeisel specific grindability (Wt) - are used. Generally, the grindability tests are carried out under relatively simplified circumstances, in a special dry batch mill with defined feed size material until prescribed conditions are reached at room temperature. However, in the fine- and ultra fine grinding, which is a frequent task (fly ash, tailings, alumina, etc), a fine material (<50 - 200 ¦m) is usually ground down to the few micrometers. The conventional grindability testing methods and apparatuses (Bond-, Hardgrove-, Zeisel-processes) for their determination, although, are not suitable directly to measure the grindability of such fine materials, since the maximal particle size of the feed material (0.5 - 3 mm) to be tested is much higher. One of the important goals of the research carried out in our Institute was to develop the novel grindability testing methods, which are suitable for the fine and ultra fine grinding, and additionally provide the possibility for the fast determination of the grindability. In order to realise the above aim the conventional Bond- and Hardgrove- mills were modified in order to directly measure the grinding work. In particular, the Hardgrove-mill was equipped with a simple torque-meter (load cell). The Bond-mill was rigged with a digital electric power measurer. The systematic experiments were carried out parallel in both mills using the conventional and the developed methods. Finally the results of both were compared. The measuring results have proved that the Bond-work index can be determined based on the developed methods. The new grindability testing methods were applied successfully in several industrial research tasks for the determination of the specific grinding energy and the Bond-work index. These methods can be also used in the industrial practice for the control of the grinding process.

Sep 13, 2010

By Jurgen te Kook

State-of-the-art for subsidence calculation are stochastical models. Although these models were successfully used all over the world they have their limitations due to the fact that they are not based on mechanical laws. For example the models did not take the rock mass structure and the rock mass characteristics into account. Therefore in a research program the skills of geomechanical numerical models for subsidence calculation were investigated. A case study shows that numerical models which are in principle based on the elastic theory are suitable for subsidence prediction. Due to the principles of these models the results are not sufficient in the case of multiple seam extraction. More extended geomechanical numerical models like FLAC and UDEC were investigated in further steps of the research work. Up to now large area geomechanical models require unrealistic long calculation times if the level of detail is similar to that of small scale calculations. Due to this it was necessary to implement a simplified description of the rock mass structure and characteristics. Different case studies show that this approach is successfull for subsidence calculation by numerical geomechanical models even for multiple seam extraction.

Jan 1, 2008

By Morris Cohen

This paper deals with the calculation of the composition of the infinitesimal trace of alloy that transfers from the liquid to the solid state at each temperature during the equilibrium solidification of a binary solid solution, and which thereby enables the compositions of the coexisting liquid and solid phases to follow along the liquidus and solidus lines respectively during the cooling. A general expression for the composition (d) of the liquid-to-solid transfer at each temperature has been derived: d = ZLXL(XL - P) + Zsxs(P- ZL(XL - P) + Zs(P - Xs) where ZL and Zs are the slopes of the liquidus and solidus lines at the given temperature, XL and xs are the composi-tions of the stable liquid and solid phases at the same temperature, and P is the composition of the alloy under considera-tion. The d equation is valid for the process of equilibrium heating as well as cooling, and may be applied to vapor-to-liquid, vapor-to-solid, liquid-to-liquid, and solid-to-solid transfers if the corresponding equilibrium diagrams are known. The d -versus-temperature curves for two alloys Pl and P2 are shown in Fig. I. In each case, the liquid-to-solid transfer has the same composition as the stable solid FIG. I.-GENERAL SOLID SOLUTION DIAGRAM SHOWING S CURVES FOR ALLOYS P1 AND P2. phase only at the temperature of the be-ginning of solidification, and has the same composition as the stable liquid phase only at the temperature of the completion of solidification. At each intermediate tem-perature, the composition of the liquid-to-solid transfer differs by a finite amount from those of the two coexisting phases. Therefore, during equilibrium cooling, the transfers must merge into the solid phase from the liquid without forming a transition phase; otherwise the condition of equilibrium would be violated. At any given temperature during solidification, the composition of the liquid-to-solid

Jan 1, 1940

By M. Stoica

Bioremediation is a complex process which involves mass transfer, chemical and biochemical phenomena. In particular, the adsorption kinetics of a substance by biomass may by model by taking into account: - Enzymatic kinetics type; - Combined kinetics - enzymatic kinetics at the same time with the Monod type biomass growth; - Chemical kinetics for substance adsorption according to Freundlich and Langmuir ad-sorption isotherms; - New empirical kinetics models based on experimental data. In this paper modelling of kinetics of bivalent lead ions on live vegetal biomass (aquatic plant Pistia stratiotes) as well as of hydrocarbons on dead vegetal biomass (pyrolysed nuts) is studied (Stoica, 2004). Modelling was carried out using experimental data and relative equations with an error of 5%.

Jan 1, 2006

The Musselwhite mine, located in northwestern Ontario, Canada, has been an underground narrow-vein gold producer since the spring of 1997. As an exploration project at the feasibility stage, much effort was undertaken to generate a geostatistical resource model that would integrate the orebodyÆs geological features, as well as the controls on mineralisation. Today as an operating mine producing over 200 000 ounces of gold per year, reconciliation studies of the tonnes and grades treated at the mill, with the feasibility model, for longer time periods, and with the grade control models, for shorter time periods, show results that are in good agreement. It was clearly demonstrated with the reconciliation to production, that the key to good reconciliation remains in the proper selection and application of the geological resource estimation method. The application of a grade interpolation technique capable of capturing threedimensionally pertinent geological features, as well as accounting for spatial grade continuity, proved to be successful in the predictability of tonnage and grade at the Musselwhite mine. Along with good mine practices, this approach, which was carried through to the operation, has produced excellent reconciliation results. The ongoing reconciliation studies at Musselwhite allow for a constant revision of the grade estimation strategy. In return, this optimisation process adds value by raising the accuracy level of production expectations. As this is an evolving practice at the mine site, further implementation developments are recommended to integrate these reconciliation procedures on a more regular basis.

Jan 1, 2002

By Kan Song, Lin Liu, Hengzhi Fu, Jun Zhang, Haijun Su, Xiaojiao Jia

"Al2O3/YAG/ZrO2 eutectic in situ composite has been regarded as new generation of high temperature structural material due to its excellent performance even close to its melting point. The directionally solidified Al2O3/YAG/ZrO2 eutectic ceramics are prepared by recently developed Laser Floating Zone Melting (LFZM) apparatus in which a splitter mirror is used to obtain two beams with the same quality from one CO2 laser. With the two laser beams irradiate the sample from opposite directions, the sample is zone melted. The apparatus configuration and the solidification processing are described in detail. The solid/liquid interface morphology is studied and the mechanism of microstructure formation especially the characteristic of eutectic cellular is discussed. It is shown that YAG and ZrO2 phases play a leading role during the ternary eutectic growth. Meanwhile, the relationship between the solidification microstructure and the processing parameters are investigated.IntroductionAl2O3/YAG/ZrO2 ternary eutectic in situ composite, due to its excellent high temperature mechanical properties, is now considered to be a promising candidate material as a replacement of nickel based super alloy for new generation aero space engine turbine blade [1]. They exhibit flexural strength of 360-500 MPa from room temperature to 2073K in air atmosphere [2]. The compression creep strength at 1873K is 433MPa with the strain rate of 104/s [3]. However, because of the high melting point and complex physical properties, there remain still many difficulties for its application. One of the bottlenecks is the poor understanding of the relationship between microstructure and solidification conditions."

Jan 1, 2012

Jan 1, 1928

In 1987 Wyoming became the largest coal producing state in the country. The state is known for its extensive coal resources and extremely thick coal seams. Wyoming's coal reserves total about 69.3 billion tons, or 14.2 percent of the U.S. coal reserve. Coal seams range generally from 10 to 80 feet in thickness, although one seam is 220 feet thick. The coal-bearing areas of Wyoming underlie approximately 41 percent of the state's total land area. Wyoming's coal ranges from lignite to high volatile bituminous. Most of the coal produced is subbituminous from the Powder River coal region near Gillette. The presence of coal in Wyoming was discovered before 1834 on the Belle Fourche River. The state's first mine opened in Carbon County in 1865, and with the completion of the trans- continental railroad, the demand for coal increased. Currently approximately 80 percent of Wyoming's coal production is shipped out-of-state to meet the growing demand for low- sulfur coal to fuel electric generating plants. Wyoming received conditional regulatory approval November 26, 1980. Its Abandoned Mine Land Program was approved February 14, 1983.

Jan 1, 1992

By J. M. Davey

Lead-zinc sulphide ores at Mount Isa are currently treated at the rate of 180,000 long tons per 28 day period in the No. 2 Concentrator of Mount Isa Mines Limited. Prior to June 1966 lead-zinc ore was treated in part of the No. 1 Concentrator up to a rate of 70,000 long tons per period. Since 1955, two major changes in ore type being processed have occurred. Because of these changes, problems arising from treatment of the ore have altered and during the period several major changes in practice have been advocated and experimentally tested. Most of these flow sheets were developed with a view to overcoming one major problem in the ore. These were invariably abandoned as the Mount Isa lead-zinc ore contains a number of equally major problems all of which must be overcome in the treatment process. MINERALOGY The orebodies are situated in the Mount Isa Shale Group which is Proterozoic in age (Carpentarian System). The sediments consist dominantly of fine grained dolomitic, quartzo-feldspathic shales and siltstones. Specifically, the Mount Isa orebodies lie in the Urquhart shale formation which is characterised by sediments of high albite and orthoclase content denoting a large volcanic component. The Urquhart shales are approximately 3,500 feet thick and extend at least north and south of Mount Isa for 20 miles in each direction. In the area of the silver-lead-zinc orebodies the Urquhart shales are highly pyritic and have a relatively high carbon content. The

Jan 1, 1970

By P. M. Blair

This paper presents numerical solutions of the equations describing the imbibition of water and the countercurrent flow of oil in porous rocks. The imbibition process is of practical importance in recovering oil from heterogeneous formations and has been studied principally by experimental means. Calculations were made for imbibition of water into both linear and radial systems. Imbibition in the linear systems was allowed to take place through one open, or permeable, face of the porous medium studied. ln the radial system, water was imbibed inward from the outer radius. The effects on rate of imbibition of varying the capillary pressure and relative permeability curves, oil viscosity and the initial water saturation were computed. For each case studied, the rate of water imbibition and the saturation and pressure profiles were calculated as functions of time. The results of these calculations indicate that, for the porous medium studied, the time required to imbibe a fixed volume of water of a certain viscosity is approximately proportional to the square root of the viscosity of the reservoir oil whenever the oil viscosity is greater than the water viscosity. Results are also presented illustrating the effects on rate of imbibition of the other variables studied. INTRODUCTION The process of imbibition, or spontaneous flow of fluids in porous media under the influence of capillary pressure gradients, occurs wherever there exist in permeable rock capillary pressure gradients which are not exactly balanced by opposing pressure gradients (such as those resulting from the influence of gravity). The importance of such capillary movement in the displacement of oil by water or gas was recognized in early investigations and described by Leverett, Lewis and True in 1942.1 Methods advanced by these authors for studying the process using dynamically scaled models were rendered more general and flexible by the research of later workers.2"4 The influence of capillary forces in laboratory water floods has also been discussed by several authors.6 While imbibition plays a very important role in the recovery of oil from normal reservoirs, Brownscombe and Dyes7 pointed out that imbibition might be the dominant displacement process in water flooding reservoirs characterized by drastic variations in permeability, such as in fractured-matrix reservoirs. In water-wet, fractured-matrix reservoirs, water will be imbibed from fractures into the matrix with a countercurrent expulsion of oil into the fractures. If the imbibition occurs at a sufficiently rapid rate, a very successful water flood can result; if the imbibition proceeds slowly the project might not be economically attractive. Scaled-model studies have demonstrated the vital importance of imbibition in secondary recovery in fractured reservoirs. It is therefore important in the evaluation of waterflooding prospects to develop a thorough understanding of the quantitative relationships of the factors which control the rapidity of capillary imbibition. The imbibition process serves reservoir engineers in still another important way by providing a technique for studying the wettability of reservoir core samples. Such experiments are usually conducted by observing the rate of expulsion of oil or water from core samples submerged in the appropriate fluid. Several papers have been 'published on the experimental techniques involved?? Although Handy has recently published a method for calculating capillary pressures from experiments with gas-saturated cores, it has not yet been possible to deduce quantitative information regarding water-oil relative permeability and capillary pressure characteristics of the rock from the experimental results. Thus a technique is needed for studying the quantitative dependence of imbibition rate on oil and water viscosity, initial water saturation, relative permeability-saturation, and capillary pressure-saturation relations. The development of such information, including saturation and pressure profiles by laboratory experiments, would be very difficult. However, recent advances in the applica-

Jan 1, 1965

By Howard W. Miller, Charles R. L. Oder

Approximately 5000 tons of zinc ore a day was mined during 1943 in the Mascot-Jefferson City district in East Tennessee. This ore came from the Kingsport formation, a part of the Knox dolomite, of Ordovician age. The Kings-port is composed of 350 to 400 ft. of limestone and dolomite. Thin cherts, sandy layers and shales are numerous. Frequently, the limestones are altered to crystalline dolomite. The Kingsport is divisible into four main lithologic zones. These divisions are illustrated in an accompanying table, which gives detailed sections of the ore-bearing beds as found in the mines and shows the exact positions of the various ore zones within the formation. Key beds are described and the practical applications of stratigraphy in mapping, prospecting and mining are discussed. Introduction The Mascot-Jefferson City zinc district is in Knox and Jefferson Counties, in the Great Valley of East Tennessee. It extends from Mascot, I3 miles northeast of Knoxville, to Jefferson City, about 30 miles northeast of that city. The American Zinc Company of Tennessee is producing from five mines in the district, in which it has operated for more than 30 years. The only other important producer is the Universal Exploration Co. The approximate daily production of the district in 1943 was 5000 tons of sulphide ore, grading from 2.5 to 6 per cent zinc. Small amounts of oxidized ore are mined intermittently. The Knox dolomite has been described by various geologists,'-' but no detailed descriptions of the rock sections revealed by mining have been published. Rock units are not conspicuously different and careful study is required to distinguish them. Nevertheless, familiarity with the stratigraphy of the mineralized zones is essential to successful exploration and extraction of the ores; therefore the purpose of this paper is to give detailed stratigraphic sections as measured in the mines, to discuss their important features and to show their relationship to the stratigraphy of the district. Generalized Section Table I gives the most characteristic general features of the major stratigraphic units. The formation names given in parenthesis are locally and widely used terms, the correlations of which are not necessarily established. For this reason they are put in quotation marks and are replaced by more restricted terms. The names "Mascot" and "Kingsport" were adopted from local towns. They were chosen jointly by Josiah Bridge, of the Federal Geological Survey, and the senior author for use in their separate unpublished manuscripts describing the Knox dolomite in East Tennessee. Descriptions of the type sections may soon be published. The name "Longview" was first applied by Butts6 in Alabama.

Jan 1, 1949

By Burt C. Mariacher

Two AIME sponsored symposia to be held during the year 1970 will examine copper, lead and zinc metallurgy in considerable depth. MBD and the Extractive Metallurgy Division of The Metallurgical Society will participate in both. Thus, the full field of minerals and metals processing including milling, smelting, and refining will be covered. Since these symposia hold special interest to MBD members, it was felt that a useful purpose could be served by devoting this column to a description of what has been arranged for the registrants.

Jan 1, 1970

By S. R. L. Harding

"Introduction0N MAY 2th, 1953, Socony Seaboard Pembina No. 1 well, located 70 miles west-southwest of Edmonton, was completed as a producer of high-gravity oil from the Cretaceous Cardinm sand. This event is possibly the most significant in the development of the oil industry in Western Canada since the Devonian discovery at Leduc in 1947. The result of the Pembina discovery and the follow-up drilling has been a tremendous increase in interest in the Cardium formation.Descriptions of the Cardium formation, as it occurs in the 'Central Foothills' and in the 'Southern British Columbia Foothills' have been presented by R. E. Folinsbee (9)-and C. R. Stelck (21), respectively. The purpose of this paper is to discuss the more regional aspects of the subject.The name Cardium was first used .as a stratigraphic term in 1863. Dr. James Hector ( l2), geologist attached to Captain John Palliser's exploratory expedition, gave the name 'Cardium to the whole section of marine Cretaceous beds exposed along the Bow river west of Calgary."

Jan 1, 1955

By André Bérubé

Since the disappearance of Les Forges du Saint-Maurice at the end of the last century, many historians have taken an interest in the lengthy past of this enterprise. They considered the political, socio-economic, administrative and anecdotal aspects of the industry, but barely dealt with the elements of technology. The purpose of this article is to try to fill this gap (1). Les Forges du Saint-Maurice was an integrated industrial concern, specializing in the production of semi-finished wrought iron and finished cast iron that operated almost without interruption between 1734 and 1883. Les Forges first came into being in 1729, when Montreal merchant Franc;ois Poulin de Francheville submitted to the King of France a request for the right to exploit the bog iron ore deposits on his seigneury of Saint-Maurice. This request, agreed to in 1730, was one of a long series of attempts, previously unsuccessful, to establish a local iron industry in the colony. Several such proposals were held up by a lack of capital from promoters or a too rigid application of the mercantilist policy by the metropolis. In 1730, however, the French minister Maurepas favoured a more liberal policy which would encourage private enterprise. The benefits of an iron industry to the naval construction industry was a factor that caught the attention of administrators. The choice of the site for Les Forges was based on the following factors: - the abundance of surface deposits of bog iron ore in the Saint-Maurice region; - the presence of a vast supply of hardwood and conifers needed in large quantities by this industry; - the proximity of sandstone and limestone deposits, md1spensable materials for the construction and operation of the blast furnace; - the presence of a water stream, with sufficient flow to provide the hydraulic power needed for the operation of the machinery.

Jan 1, 1999

By R. Van A. Mills

This preliminary paper is intended to answer briefly some of the inquiries coning to the Bureau of Mines regarding the so-called "paraffining", of oil wells and methods of preventing and remedying that trouble. The increased difficulties in operation and the losses of production caused by the deposition of gummy and waxy hydrocarbons, commonly called paraffin, in the wells, tubing, other pumping equipment, and in the pores of the productive sands, have long been recognized but the trouble has not been overcome. The nature and causes of the trouble, together with some of the possible methods by which it may be diminished or overcome, are outlined below. Character of the Peraffining Materials. The so-called paraffin that collects in oil wells end in the pores of the oil-producing sands immediately around the wells, is generally made up of amorphous wax or uncracked paraffin, asphalt, or other gummy hydrocarbons mixed with more or lees water, oil, and inorganic silt. Some of the samples of this "paraffin" collected from oil wells in different fields and examined by the Bureau of Mines contain as mach as 20 per cent by weight of water and inorganic silt, whereas other samples are composed entirely of waxy hydrocarbons and oil. The inorganic silt accompanying this "paraffin" is mostly fine sand, clayey materials, common salt and finely disseminated precipitates of calcium and magnesium carbonates. Sulphates of calcium, barium, and strontium are less common constituents of the "paraffin."

Jan 1, 1923

By J. J. Moore

Combustion synthesis, or self-propagating high-temperature synthesis (SHS), reaction systems are discussed with respect to thermodynamics and kinetics. In particular, the effect of the process parameters, e.g. particle size, [All] ignition and combustion temperatures, on these self-sustaining reactions is discussed. Combustion theory is used to investigate the effect of the overall actuation energy of the SHS reaction on the combustion front propagation rate and in obtaining a clearer understanding of the transition from stable to unstable propagation. Finally, examples of the application of combustion synthesis to advanced materials processes are made, in particular the synthesis of Ni-Ti-X intermetallic shape memory alloys, TiC-AI2O3 and ZrB2-AI203 ceramic composite materials.

Jan 1, 1992