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By E. V. Foran

Among the many newer disclosures that have accompanied the petroleum industry's progressively deeper exploratory drilling is the increased frequency with which the operators are encountering reservoirs of which the products at the time of discovery exist wholly or predominantly in the gas phase. The popular term "distillate pool" is most often used within the industry when referring to this type of reservoir, and in this paper the term is used in that sense. These pools have been observed in many different surroundings. In some places the entire reservoir is filled with the wet gas containing its water-white condensible products in the gas phase but apparently with no dark oil or other hydrocarbon liquids in the reservoir. The 8200-ft. horizon in the Big Lake field in West Texas is a good example of this type. At other places the wet, or distillate-bearing, gas may form a large gas cap directly overlying and in contact with an extensive reserve of dark oil. Oklahoma City, Kettleman Hills, the 8500-ft. horizon in the Big Lake field, and many others are examples of this type. There are also many places in which the wet distillate-bearing gas fills nearly the entire reservoir space, while the dark oil occupies only a narrow, bandlike zone, which marks the boundary of the reservoir along its lowest productive contour. The heavier components of these deep pool gases are generally water white in color, a large portion of which are condensible in a conventional oil and gas separator, when operated under pressures of the order of 400 to 800 Ib. per sq. in. Although the water-white products recovered in the separator sometimes have end points of 650" F. and higher on standard Engler distillation, they occur only in the gas phase in the reservoir. It is entirely possible that even some small amounts of dark colored reservoir components may occur in the gas phase when the temperature is 300" F. and pressures exceed 6000 Ib. per sq. in. Close approaches to these conditions have been encountered in the deepest producing wells. The condensible content of the deep reservoir gases of the many pools that have been tested or produced to date shows a wide variation in both condensible content, per 1000 cu. ft. of gas, and physical character.

Jan 1, 1939

By E. V. Foran

Among the many newer disclosures that have accompanied the petroleum industry's progressively deeper exploratory drilling is the increased frequency with which the operators are encountering reservoirs of which the products at the time of discovery exist wholly or predominantly in the gas phase. The popular term "distillate pool" is most often used within the industry when referring to this type of reservoir, and in this paper the term is used in that sense. These pools have been observed in many different surroundings. In some places the entire reservoir is filled with the wet gas containing its water-white condensible products in the gas phase but apparently with no dark oil or other hydrocarbon liquids in the reservoir. The 8200-ft. horizon in the Big Lake field in West Texas is a good example of this type. At other places the wet, or distillate-bearing, gas may form a large gas cap directly overlying and in contact with an extensive reserve of dark oil. Oklahoma City, Kettleman Hills, the 8500-ft. horizon in the Big Lake field, and many others are examples of this type. There are also many places in which the wet distillate-bearing gas fills nearly the entire reservoir space, while the dark oil occupies only a narrow, bandlike zone, which marks the boundary of the reservoir along its lowest productive contour. The heavier components of these deep pool gases are generally water white in color, a large portion of which are condensible in a conventional oil and gas separator, when operated under pressures of the order of 400 to 800 Ib. per sq. in. Although the water-white products recovered in the separator sometimes have end points of 650" F. and higher on standard Engler distillation, they occur only in the gas phase in the reservoir. It is entirely possible that even some small amounts of dark colored reservoir components may occur in the gas phase when the temperature is 300" F. and pressures exceed 6000 Ib. per sq. in. Close approaches to these conditions have been encountered in the deepest producing wells. The condensible content of the deep reservoir gases of the many pools that have been tested or produced to date shows a wide variation in both condensible content, per 1000 cu. ft. of gas, and physical character.

Jan 1, 1939

By A. Nhasengo

Paper written on project work carried out in partial fulfilment of B. sc. Eng (Mining Engineering) The purpose of this investigation was to assess the mining strategy for steep reefs at Mine A mine in 2005 and 2006. Reefs steeper than 35° were discovered when production commenced at the mine. At that time reefs steeper than 35° were not popular in South African tabular gold mines, therefore new techniques of mining them had to be developed. The underhand mining method was chosen for this purpose. The project was about assessing ventilation, support costs, local support cycles, adherence to the mine?s support standards, mine planning and efficiencies of the underhand mining method. The project work was covered by doing a literature research for underhand mining methods and performing a literature review of the mining methods, support methods, ventilation standards at Mine A. Underground visits were conducted at Mine A mine for data collection, and Mine B was visited to obtain information on support costs and efficiencies. During the investigation it was realized that the underhand mining method was an appropriate method for mining steep reefs; however, there were some challenges related to ventilation and support installation. Efficiencies could be realized with the underhand mining method and planning and scheduling were not different from breast mining.

Jan 1, 2007

By Bror Nordberg

SAND and gravel are unconsolidated granular materials resulting from the natural disintegration of rocks. The two materials nearly al- ways occur together, variably proportioned in widely available de- posits. A commercial sand comprises the fine granular material, usually less than f in. in diameter (ASTM Designation C58-28), and gravel consists of the coarse, granular material larger than sand (ASTM Designation C125-46T). Gravel falls within the range of 1/4 in. and a top size usually of 3 ½ in. Chemical definition is impossible. Sand and gravel are always of secondary origin. They were formed from various massive rocks through the action of chemical and mechanical forces; then transported, abraded, washed, sorted, and classified by streams, glaciers, waves, or winds, to be redeposited in beds as they are found. Chief disintegrating forces in the reduction of rocks into granular particles were frost, rain, the dissolving action of acid and alkaline ground waters, the mechanical action of streams and waves, and the action of glaciers. Method of formation and deposition have imparted physical properties to sands and gravels that largely determine the commercial value of the materials for particular use and influence the manner of exploitation. In the early days of the commercial industry, purchasing specifications were relatively lenient but in. the past decade much more rigid quality requirements have had to be met for acceptance by all classes of purchasers. The trend to further severity in requirements is a challenge to the industry that commands full knowledge of the nature of raw materials at hand and skillful application of processing into commercial products. Mechanical strength, the ability to resist disintegration, chemica

Jan 1, 1949

By J. C. M. Li

The steady state shape of a shrinking cylindrical grain boundary of miform boundary energy is shown to be circular. This is based on the principle of either the minimum rate of entropy production or the minimum thermokinetic potential. The circular shape corresponds also to a state of minimum (not maximum) velocity. The steady state shape of a grain boundary moving between two inclined surfaces is a circular cylindrical arc whose position and curvature will be afjected by the nature of the surfaces. The minimum thermokinetic potential is the only valid criterion in this case. THE preceding paper1 reports an interesting experiment in which it is shown that a grain boundary moving between two inclined surfaces assumes a circular cylindrical arc whose axis nearly coincides with the line of intersection of the two surfaces. The driving force is well defined since it is the energy of the grain boundary itself. The velocity of the grain boundary is found not to vary linearly with the driving force. Several interesting questions arise: 1) What principle determines the shape of a moving grain boundary? 2) What is the effect of the inclined surfaces? 3) How do we understand the nonlinear velocity-driving force relationship? It is attempted in this paper to discuss the first two questions based on irreversible thermodynamics and in a following paper to discuss the third question based on dislocation theory. STEADY STATE SHAPE OF A SHRINKING LOOP (A CYLINDRICAL GRAIN BOUNDARY) In irreversible thermodynamics, there are two criteria for the steady state. One is the minimum rate of entropy production2 which is based on the symmetry of phenomenological coefficients and is applicable to linear force-flux relations with constant coefficients. The other is the minimum thermokinetic potential3 which is based on the integrability of a certain Pfaffian differential equation and is applicable to nonlinear systems with variable coefficients. In the case of a shrinking grain boundary loop (a two dimensional version of a cylindrical grain), the flux of atoms across the grain boundary can be taken as the local boundary velocity v measured perpendicular to the boundary (the number of atoms transferred per unit area per second is equal to the product of atom density and the velocity of the boundary). The local thermodynamic driving force can be taken as y/p with y being the grain boundary energy (invariant with respect to the orientation and curvature of the grain boundary) and p being the radius of curvature. Such driving force can be understood by considering the loop as an elastic string with tension y. As shown in Fig. 1, across a length ds along the loop, the direction of y changes by an angle d@ which is ds/p. Because of this change of direction, the tension exerts a force perpendicular to the curve equal to yd@. The force per unit length is then y/p. According to the experimental observation, the velocity v is a power function of y/p, where M is the velocity at unit driving force and 'n is a constant. The rate of entropy production per ds along the loop is vyds/pT, where T is the temperature. For a given length L of the loop, the total rate of entropy production is The thermokinetic ptentia13 has only a differential definition and its existence depends on the integrability of this definition. In this case, Eq. [3] happens to be a total differential and the thermokinetic potential can be defined as which turns out to be the same as the rate of entropy production, Eq. [2], except for a constant factor n + 1. Strictly speaking, since the flux-force relation is not linear, the rate of entropy production may not be a minimum at the steady state. However, because of the proportionality between Eqs. [2] and 141, the state of minimum thermokinetic potential happens to be the same as that of minimum rate of entropy production. The steady state shape thus can be obtained by minimizing either integral [2] or [4] for a given L.

Jan 1, 1970

By M J. Saynor, W D. Erskine an, D R. Moliere

The Jabiluka uranium mine was constructed in the Ngarradj catchment, a right bank tributary of Magela Creek in the Northern Territory. The Jabiluka Mineral Lease is adjacent to Kakadu National Park, near an area listed as Wetlands of International Importance under the Ramsar Convention and recognised under the World Heritage Convention. In the late dry season of 1998 and prior to the 1998 - 1999 wet season, a stream-monitoring program was implemented in the Ngarradj catchment to collect baseline data on sediment transport within the catchment to assess and proactively manage associated impacts caused by mining at Jabiluka. Stream suspended mud concentration, stream discharge and rainfall data were collected for four wet seasons (1998 - 2002) giving an almost continuous data set. The stream system has high natural variability dependent on rainfall intensity and subsequent discharge and pre-wet season fire distribution and intensity. In general, mud concentration is elevated at the commencement of the wet season until about February. This is caused by first-flush removal of surface material detached during the dry season by agents such as bioturbation (including anthropogenic activity), wind erosion and surface desiccation. Water quality trigger values downstream of the mine were derived using upstream percentiles and the before-after-control-impact, paired site design. Both analyses showed no observable impact from mine construction in 1998 or during the study period. However, the impacts of dry season fires could be clearly detected. The data set provides good baseline information for future assessment at Jabiluka and demonstrates the need to view measured parameter values on a catchment-wide basis with knowledge of rainfall, discharge and fire distribution.

Jan 1, 2004

By W. W. Schmittroth, A. Y. Bethune

THE commercial analysis of Special High-Grade zinc usually involves the determination of lead, iron, copper and cadmium as impurities in the base metal. Over the past 20 years, as the result of metallurgical improvements in the art of producing Special High-Grade zinc metal there has taken place a gradual exclusion of almost all extraneous elements, and the few that do remain in the final product have been virtually reduced to the vanishing point. Thousands of tons of zinc .are now commercially produced annually and made available to the trade, in which impurities are present only in the order of 0.0010 per cent or less and the sum total of all impurities does not exceed 0.0025 per cent. To such zinc the term "superpurity" might well be applied without undue exaggeration. The techniques used for production control and final analysis of Special High-Grade zinc by means of emission spectra in the laboratories of the electrolytic zinc plant of the Sullivan Mining Co. are based on the premise that self-electrodes are to be preferred over all other forms for the examination of the zinc in question. Furthermore, after a survey of the literature and considerable experimental work,1 it was decided that the spectrographic method of internal control, the principle of which was first announced by Gerlach,2 using a modification of the high-voltage alternating-current arc source introduced by Duffendack and Thompson,3 with the calibration of each photographic plate as recommended by Wolfe,4 would yield the most accurate and reproducible results. Self-electrodes were chosen in order to make use of one of the unique advantages inherent in spectrographic analysis; namely, the rapid and almost effortless detection of elements other than those being quantified by the analyst; or conversely, the proof that the zinc is free from such impurities if no spectral line of the suspected element appears. This fact was verified for certain elements, and will be discussed later. Carbon electrodes impregnated or packed with zinc salts chemically prepared from the zinc to be assayed were avoided for a number of reasons. First, the chemical manipulation was another time-consuming step, which increased the chances for contamination. Second, none of the common zinc salts, such as the chloride, nitrate or sulphate, yielded reproducible results under our conditions, nor did the spectral line of the impurity appear as readily in the low concentrations as when using zinc metal. Third, no commercial carbon, except the very expensive, was pure enough to use with this grade of zinc and the continued time, effort and expense incurred in the purification of carbon was not desirable. The use of Special High-Grade zinc self-electrodes introduces certain complications with regard to obtaining satisfactory excitation conditions, because it seems necessary to raise the temperature

Jan 1, 1946

By J. C. Bayles

It is seldom the privilege of one who contributes to the Transactions of a technical society, to describe a new industry in which, by processes employed for the first time, are attained results of conspicuous value. There are but few such patches of virgin soil worth the tilling, within the area circumscribed by the industries which have experienced a regular and uniform development. New and startling methods in production are often announced as about to be introduced; but, as a rule, they take their place among the " large desires with most uncertain issues," or give new significance to the historic words of an eminent statesman concerning " the bright beginnings and the bitter end of a halcyon and vociferous proceeding." In this paper I shall have the pleasure of briefly describing a new industry which has been established without announcement or proclamation — the manufacture of serviceable pressure pipes of great strength, from strips of steel or iron wound spirally, heated only along the overlapping edges, welded by hammering and finished into tubes of uniform diameter, and of such length as mag be found convenient in handling and transportation. As such tubes are now manufactured on a considerable scale, in a range of sizes which will soon include everything between 4 inches and 30 inches, and as much larger as may be needed, both process and product are likely to be of interest to engineers in all departments of professional work. The raw material of the industry is the ordinary sheet-iron or steel of commerce, of such lengths and widths as it is convenient to roll. The range of the ganges of the metal which can be employed has riot yet been determined. The lightest metal thus far successfully made into pipe is No. 29 iron, and the heaviest a steel gauging somewhere between 12 and 14. Heavier machines are now building which will bend steel .165 of an inch in thickness, or No. 8 of' the Birmingham gauge. Probably No. 20 or No. 22 will be the lightest used in making commercial pipes; hut the experiment with No. 29 was interesting as showing the readiness with which the flame can be controlled. To get a welding heat with such thin

Jan 1, 1888

By M. A. Halim, V. I. Lakshmanan, Z. Jankovic

An innovative mixed-chloride process for the separation of iron from lateritic ore is described. The separation of Fe(III) from leach liquor is an important process step for the recovery of nickel and cobalt. The patented process of Process Research ORTECH Inc. uses a lixiviant containing hydrochloric acid (HCl) and magnesium chloride (MgCl2) for the leaching of lateritic ores/concentrates followed by the selective solvent extraction step of Fe(III) over other value metals such as Ni and Co. The use of MgCl2 increases the activity of the hydrogen ion in the lixiviant, which reduces the consumption of HCl in the leaching stage and enhances the formation of HFeCl4-, thereby increasing the solvent extraction efficiency of Fe(III) with ketone. The process produces high purity iron oxide (Fe2O3) and regenerates HCl by the pyrohydrolysis of the FeCl3 rich pregnant strip solution. The developed process flowsheet is in closed loop, economically attractive and environmentally friendly.

Jan 1, 2015

By Zay Jeffries

Each generation accepts the developments of the preceding generations without full appreciation of the difficulties that had to be overcome or of the effect of any given development on society. Today, the production of pig iron is the yardstick with which general industrial health and progress are measured. So natural and logical does this seem to us, that it is difficult to picture conditions prior to the fourteenth century when pig iron was unknown. Not only was pig iron unknown but iron or steel could not be melted and poured into castings; all iron and steel articles were forged from sponge iron. All castings, as well as many worked articles, were made of non-ferrous metals or alloys. In many parts of the world, over long periods of time, not only was the annual exchange value of non-ferrous metals greater than that of iron and steel, but their combined tonnage was greater. At present, the value of the pig iron produced in a year is of the same order of magnitude as that of all non-ferrous metals combined; the tonnage of pig iron is, however, about twenty times that of all non-ferrous metals combined. Owing to lack of records, we will probably never know the relative importance of the various metals at all periods in historic times. A certain conclusion is that the iron and steel industry, since the discovery of pig iron and the cheap methods of converting it into steel, has grown at a much more rapid rate than the non-ferrous metal industries. Notwithstanding their fundamental fitness for man's needs, iron and steel owe their importance in no small degree to the low cost of production. The low cost was a result of increased knowledge of the production appliances and of the metallurgical processes. This increased knowledge is the key to our modern industrial civilization. It will remain for future generations to determine whether there is now going on a gradual change toward greater importance of the non-ferrous metals, as compared to iron and steel. The world's pig iron production in 1920 was slightly more than twice what it was in 1890, whereas the non-ferrous metals production in 1920 was about two and one-half times that in 1890. Every non-ferrous metal industry has shown marked growth during the last thirty years. During this period, the production of cop-

Jan 1, 1924

By Siân E. Boyd

Studies of benthic recolonization in the aftermath of marine aggregate dredging in the U.K. and elsewhere are limited and are largely confined to experimental circumstances. Investigations of the physical and biological status of licensed extraction sites in the U.K. at various times following cessation of commercial dredging are very limited, and so judgments as to the likely progress towards environmental restoration and the time-scales involved continue to be based on predictions rather than real data. This field-based research programme was commissioned to enhance the understanding of processes leading to physical and biological recovery of the seabed following dredging, thereby aiding the identification of practices to minimize environmental harm at licensed sites, and to promote rehabilitation on cessation. The outcome of survey work will have the notable benefit of allowing questions about the present status of locations hitherto subject to commercial exploitation to be answered directly, rather than by inference.

Jan 1, 2002

By Clifford R. Stanley

"Abstract - Reproducible analyses of representative samples for elements affected by the ‘nugget effect’ is vital in mineral exploration and reserve estimation. Unfortunately, a priori knowledge of what size of sample is representative from a mineral deposit or its dispersion train is commonly unavailable. Use of the simple ‘equant grain model’ and the NUGGET computer program facilitates determination of the sampling parameters that will produce appropriate samples for chemical analysis. Based on Poisson statistics, NUGGET can be used to determine: (1) the ‘effective grain size’ of nuggets in a suite of samples, (2) the level of representativity (precision) that samples with specific nugget grain sizes will exhibit, and (3) the sample size required to obtain a specific level of sample representativity. The program determines these sampling parameters for any element in any mineral, including solid solution minerals (e.g., Au, electrum, Pt-Fe alloy, diamond), and allows assumption of a variety of grain shapes (e.g., ellipsoids, cylinders, parallelepipeds, etc.). Furthermore, it outputs the effective number of nuggets expected in a sample of given size and the percentile confidence bounds on any element concentration affected by the nugget effect.Results from the software allow determination of effective sampling and analysis strategies that minimize the nugget effect in geochemical analysis/assaying used in mineral exploration and reserve estimation. This will not only improve confidence in the resulting exploration results or reserve estimate, but will facilitate estimation of the error associated with any subsequent interpretation or reserve figure."

Jan 1, 1998

By E. Breinan, M. Salkind

Al3Ni whiskers were chemically extracted from unidirectionally solidified Al-A13Ni eutectic ingots, bent into loops, and heated for 0.1 to 10 hr at 320°, 415", and 510°C. The initial strains ranged from 0.003 to 0.055. In all cases, permanent plastic deformation was noted after heat treatment. The deformation consisted of relatively uniform bending at low stresses and temperatures and short times and kinking followed by fracture at high stresses and temperatures and long times. After kinking, the whisker segments adjacent to the kinks were found to have straightened, which is evidence of a dislocation condensation mechanism. The range of temperatures and strains at which time dependent plastic deformation was found indicates that creep of whiskers probably plays a role in the creep of A13Ni whisker-reinforced aluminum. WHISKERS may be defined as nearly perfect single crystals which exhibit high strength. Because they can support high stresses at relatively low strains, they have been successfully employed in reinforcing metals at both ambient and elevated temperatures. In studying the creep behavior of A13Ni whisker-reinforced aluminum at elevated temperatures,1,2 it was noted that the composites exhibited measurable creep deformation. This investigation of the creep relaxation of individual A13Ni whiskel, extracted chemically from the composite was initiated to determine if creep of whiskers could con. "bute to the overall creep of the composite material. Many observations of plastic deformation of metal and halide whiskers have been made. Brenner3-8 noted that copper, silver, and iron whiskers exhibited heterogeneous plastic deformation at room temperature when strained beyond their yield points. Gyulai9 and Gordon10 observed plastic deformation of relatively large (>3 µ) NaCl and KC1 whiskers, although the smallest, most perfect whiskers were completely elastic. Eisner" noted plastic deformation and microcreep of iron and silicon whiskers at room temperature after straining beyond the yield point. Whiskers reported to exhibit creep at stresses below the yield point were zinc1'-" and Silicon.15 Cabrera and price" observed some zinc whiskers which crept at room temperature after a short incubation period but then stopped creeping after a short time. Because some of their specimens exhibited no creep, they concluded that those whiskers that crept were relatively imperfect. Pearson, Reed, and Feldman15 observed similar creep behavior of silicon whiskers at 800°C. They also concluded that creep of the whiskers was a result of imperfections in their crystals. Brenner16 observed delayed failure of A12O3 whiskers at elevated temperatures but found no evidence of plastic deformation up to 2030°C (99 pct of E.EREINAN and M.SALKIND,JuniorMembers AIME,are Research Scientist and Chief, respectively, Advanced Metallurgy Section, United Aircraft Research Laboratories, East Hartford, Conn. Maunscript submitted April 5, 1968. IMD the melting temperature). Brenner also noted7 that some copper and iron whiskers exhibited delayed kinking above 350°C while others did not. One can conclude from these observations that small relatively perfect whiskers could exhibit completely elastic behavior during sustained elevated-temperature loading of composites. Since A13Ni whiskers tested in both bending and tension were found to exhibit no evidence of plastic deformation at room temperature'7'18 this study was initiated to determine whether or not creep of A13Ni whiskers occurred at the elevated temperatures at which creep in the composites was observed. Whiskers were chemically extracted from ingots of unidirectionally solidified A1-A13Ni eutectic, constrained in bending to various elastic strains and heat-treated. The bending constraints were removed after heat treatment and the amount of permanent set was taken as a measure of the time-dependent plastic deformation. EXPERIMENTAL PROCEDURES Ingots of eutectic Al-A13Ni containing nominally 6.2 wt pet Ni were unidirectionally solidified at approximately 11 cm per hr using a process described elsewhere.19,20 The starting materials were 99.99 pct pure. Cylindrical sections cut from the center of each ingot were placed in a 3 pct aqueous solution of hydrochloric acid and the whiskers were extracted as described previously.17 The whiskers nearest the surface were blackened somewhat due to overexposure to the acid while the center of the ingot was being dissolved These partially attacked whiskers were discarded. An intermediate zone of silver-gray-colored whiskers was collected and stored in methanol for use in relaxation experiments. Individual long pieces of A13Ni whiskers were placed on Fisher Precleaned Microscope Slides. These normally straight whiskers were bent elastically into arcs or loops of varying radii by manipulating their ends with a slender probe. The mass attraction between the whisker and the probe was sufficient to cause the whisker to follow the probe. The whiskers were retained in the elastic bend by the surface tension of a fine residual film on the slides. By using long whiskers, the action of the surface tension on the unlooped ends of the whisker allowed high elastic strains to be maintained in the loops. After each whisker was bent, a photomicrograph was taken for use in measuring the bending strain. The range of strains studied was 0.003 to 0.055. The bent whiskers were then encapsulated in Pyrex tubes at pressures between 10"6 and 5 x 10"6 mm of mercury and heat-treated at 320°, 415°, and 510°C (respectively 53, 61, and 70 pct of the peritectic decomposition temperature). After each heat treatment, the liquid film on the slides was found to have dried, but the whiskers were held in their original shapes by a residue on the slide. The minimum radius of curvature of each bent whisker was measured before and

Jan 1, 1969

By D. Fourie

A brief history of channel sampling in South African gold mines is followed by a chronicle of different sampling events and sampling methods that used the traditional ?hammer and chisel? approach as well as diamond core extraction of the sample. The problems associated with each method of sample collection are documented and the use of a laser scanner to measure the exact volumes of sample material extracted from a correctly delimited sample site are considered. Areas where increment delimitation errors (IDEs), increment extraction errors (IEEs), increment weighting errors (IWEs), and increment preparation errors (IPEs) occur were investigated. A ?simulated chip sample model? is introduced and provides the basis for comparing the percentages of error introduced as a result of improper sampling. The heterogeneity experiment showed that reefs that are more homogenous tend have lower extraction errors than the more complex carbon-rich reefs, which may contribute to understanding the poor mine call factor on mines exploiting the latter types of reef. Keywords channel sampling, chip sampling, error, bias, modelling.

Jan 1, 2014

By Wieslaw Wszolek, Kazimierz Trybalski, Ryszard Tadeusiewicz

"The present work is an attempt of neural networks application to the description of complex technological processes of useful minerals enrichment. Neural networks are among the most convenient tools that have been added recently to the professional toolbox of modelling specialists, and they are particularly useful in realisation of multiple practical tasks, characterised by great complexity and relatively low amount of available a priori knowledge about the nature of the modelled processes. They are successfully applied in a wide variety of problems related to data processing and analysis, their prediction, classification or process control. The object of the study was the technological site for copper ore enrichment by floatation, being a part of technological line in the Ore Enrichment Plant ZG „Polkowice”, KGHM „Polska Miedz” S.A.The main floatation is described by parameters measured by the supervision and control system, which can be grouped with respect to the functions performed for the object:a) input function: aFG - copper contents in the feed material for the main floatation [% Cu]b) control: LFG I - level in the first section of the floatation unit [%], LFG II - level in the second section of the flotation unit [%], LFG III - level in the third section of the floatation unit [%], LFG IV - level in the fourth section of the floatation machine [%]. These quantities compose the five elements long input vector.c) output function: ? - copper contents in the waste from main flotation (final waste) [% Cu]The measurement data, containing the above-mentioned parameters, have been collected during the normal operation of the plant. The data contain momentary values of the parameters, registered every 10 minutes, covering the period of 196 hours of the plant’s operation (1176 measurements for each quantity).For construction of the model used in the study classical multi-layer perceptron-type neural network has been used, with one hidden neuron layer, trained by the error back propagation method."

Jan 1, 2003

By K. C. Shaver

The Sloan Ranch kimberlite complex is located approximately 130 km north-northwest of Denver in the Precambrian core of the northern Colorado Front Range (Figure 1). A Devonian age for the complex is suggested by the fossil assemblages in limestone xenoliths (Chronic and others, 1969), and by paleomagnetism of the kimberlite (E. E. Larson, personal communication, 1986). The presence of diamond was first reported in rocks from the Sloan diatreme by McCallum and Mabarak (1976). Prior to this time, the distinctive- appearing host rock of the Sloan diamonds had been quarried for use as terrazzo stone; examples may be seen in the floors of the airports in Cheyenne and Laramie, Wyoming. The Minerals Division of The Superior Oil Company obtained a lease on the Sloan property in 1980. During the next four years Superior built and fine-tuned a highly efficient diamond recovery facility, explored and tested the Sloan deposit, and used Sloan as a site for testing numerous exploration techniques for future use in a continuing exploration program in the Colorado-Wyoming kimberlite province. The Sloan property was ultimately determined to be sub- economic, but the lessons learned there have been very helpful in subsequent exploration efforts.

Jan 1, 1987

By J. W. Hickman, E. A. Gulbransen

In a previous paper' the authors have investigated the structure of the oxide films formed on most of the metals that make up the alloys of this study. The metals were studied in order to provide basic information on the structures, both physical and chemical, of the oxide films and to determine how these structures are effected by the temperature, time of oxidation, and surface preparation. It was felt that an understanding of the physical and chemical structure as well as the stability of the oxide film might furnish clues as to the nature of the reaction process and the protective quality of the film. The oxidation of the metals was studied over the temperature range 300' to 7o0°C. except for copper, wherc the range selected was 100' to 500°C. The results of these studies were presented in graphical form as existence diagrams of the oxides on a time-temperature scale. For some of the metals the existence diagrams were simple and showed few chemical transitions, but there were numerous cases where the physical state of the oxide surface was a function of time and temperature. In general the physical state of the oxide surface changed with increasing temperature so as to increase the sharpness of the diffraction patterns and to cause orientation effects to be more pronounced. Deviatiois in lattice Darameters from X-ray values were noted. In general these deviations were of positive nature and may be due to solid solution of the metal in the oxide lattice. This effect might be expected in thin oxide films. In a study of the oxidation of alloys containing two or more metals, there may arise the complicating factor of identification of the oxides formed. A thorough understanding of the oxides formed on the pure metals, therefore, was, essential before investigation of the oxidation of alloys. In this paper it is our purpose to present a study of the following problems: 1. The existence diagrams of various alloys. 2. The effect of the structure of the alloying metal on the existence diagram of iron. 3. The effect of the percentage of chromium on the oxides formed on Fe-Cr alloys. 4. The relationships, if any, between the oxides formed and the protective quality of the oxides. The following alloys are included in this study: alloys of iron with body-centered cubic, face-centered cubic and other metals, 13 Cr-Fe, 18-8 stainless steel, K4²B, Nichrome V, Hipernik, Inconel, Stellite "²I," Refractaloy, Kovar, mild steel, a series of Cr-Fe alloys and a series of Co-Fe alloys. Since many of the commercial alloys in this list contain more than two metals, various complicating factors in the identification of the oxides formed may arise.

Jan 1, 1947

By E. A. Gulbransen, J. W. Hickman

In a previous paper' the authors have investigated the structure of the oxide films formed on most of the metals that make up the alloys of this study. The metals were studied in order to provide basic information on the structures, both physical and chemical, of the oxide films and to determine how these structures are effected by the temperature, time of oxidation, and surface preparation. It was felt that an understanding of the physical and chemical structure as well as the stability of the oxide film might furnish clues as to the nature of the reaction process and the protective quality of the film. The oxidation of the metals was studied over the temperature range 300' to 7o0°C. except for copper, wherc the range selected was 100' to 500°C. The results of these studies were presented in graphical form as existence diagrams of the oxides on a time-temperature scale. For some of the metals the existence diagrams were simple and showed few chemical transitions, but there were numerous cases where the physical state of the oxide surface was a function of time and temperature. In general the physical state of the oxide surface changed with increasing temperature so as to increase the sharpness of the diffraction patterns and to cause orientation effects to be more pronounced. Deviatiois in lattice Darameters from X-ray values were noted. In general these deviations were of positive nature and may be due to solid solution of the metal in the oxide lattice. This effect might be expected in thin oxide films. In a study of the oxidation of alloys containing two or more metals, there may arise the complicating factor of identification of the oxides formed. A thorough understanding of the oxides formed on the pure metals, therefore, was, essential before investigation of the oxidation of alloys. In this paper it is our purpose to present a study of the following problems: 1. The existence diagrams of various alloys. 2. The effect of the structure of the alloying metal on the existence diagram of iron. 3. The effect of the percentage of chromium on the oxides formed on Fe-Cr alloys. 4. The relationships, if any, between the oxides formed and the protective quality of the oxides. The following alloys are included in this study: alloys of iron with body-centered cubic, face-centered cubic and other metals, 13 Cr-Fe, 18-8 stainless steel, K4²B, Nichrome V, Hipernik, Inconel, Stellite "²I," Refractaloy, Kovar, mild steel, a series of Cr-Fe alloys and a series of Co-Fe alloys. Since many of the commercial alloys in this list contain more than two metals, various complicating factors in the identification of the oxides formed may arise.

Jan 1, 1947

By T. Wennberg

An elevated location of a paste thickener on a ridge close to the disposal area is considered at a Swedish iron ore mine. About 0.7 M tonnes of thickened tailings are planned to be layered as paste in the vicinity of the thickener over several years with pipeline lengths of up to 900 m after about 20 years. In order to clarify the pipeline pumping characteristics of the tailings product for volumetric solids concentration from 40 to 50%, experiments in loop systems with pipeline inner diameters from 0.063 to 0.152 m have been carried out with various types of pumps. The results and comparisons carried out here showed that the performance of centrifugal pumps cannot simply be related to the rheology, but factors related to pump design and build-up tendencies of material within the pump and other particle properties may be of equal importance. During the first years of operation only one thickener underflow pump is required. The reliability and performance for various pump configurations are planned to be investigated systematically in order to meet the most effective long-term solution for paste thickener operation, pipeline distribution and placement in the disposal area as the discharge point advances over the life of the project.

Jan 1, 2007

By R. Havens, K. C. Dean, H. Dolezal

Mine, mill, and smelter wastes aggregating billions of tons are scattered across the country as unattractive barren piles that mar the natural beauty of the land. As the population of the United States increases and the demand for land intensifies, populous centers are slowly encroaching on these formerly isolated wastes. Encroachment sharply intensifies the importance of controlling the air and water pollution derived from natural weathering of such wastes. Use or stabilization of these wastes comprises the only viable means for minimizing pollution. Utilization is preferable to stabilization, because full use would both eliminate the waste and broaden the mineral resource base. However, the wastes typically comprise immense tonnages of materials discarded by selective mining or after recovering the significant mineral values by milling and/or smelting. Only rarely can such low-grade material be reprocessed to extract additional minerals at a profit. Some mineral wastes are suitable for disposal as mine fill, railroad and highway road ballast, and land fill. Similarly, some mineral wastes can be utilized as raw materials for making brick, rock wool, concrete, and ceramic products. Several means exist for stabilization of relatively fine-sized wastes, which constitute the chief sources of air and water pollution. These include physical, chemical, and vegetative stabilization, and combinations thereof. Massive coverings of coarse slag, concrete, and soil may be used to prevent erosion of waste piles. A variety of chemicals can be used to bond the particles of fine-size waste into a relatively inert mass. However, the most promising method of producing an esthetically appealing storage site is vegetative stabilization. Numerous species of plants can germinate, grow, and reseed in waste materials which have been adequately prepared to support plant life.

Jan 3, 1969