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By Louis D. Huntoon

AFTER the completion, in 1905, of the Hammond Mining and Metallurgical Laboratory of the Sheffield Scientific School, Yale University, it became necessary to secure and assay a large assortment of ore-samples, and to arrange the results in such a manner as to admit of use with the least amount of work on the part of the instructor. At first, pulp-samples, together with their respective assays, were secured from the mines, smelters, and public assayers, but this practice did not prove satisfactory. It was not only difficult to secure a sufficiently large supply of material, but it was also impossible to secure the proper assortment required for instructing students. It involved considerable work for the donors to select the samples and furnish a record of the assays, and also for the instructors to examine each pulp and determine its character. Some of the samples did not contain a sufficient quantity of pulp for the student to check his work in case his first assay did not correspond to the record. In order to increase the number of samples and to vary the character of the material, pulp-samples were later mixed with barren rock and with sulphides, but this method also was unsatisfactory and has been discontinued. At present., small lots of ore are secured by gift or purchase from engineers, public assayers, and the managers of mines, mills, and smelters. These lots weigh from 10 to 100 lb. each, and are rarely finer than 0.25 in. in size. The larger samples permit of a careful study by the instructor in order to determine the best method of assaying to be followed. In universities in which assaying is taught the record of the samples should fulfill the following requirements

Nov 1, 1909

By R. H. Tien

Temperature distribution as well as position of the solidified front is solved by means of "heat balance integral", for the case of freezing a slab with time-dependent surface temperature. Numerical solutions for the cases of linear variation and exponential decay for surface temperature are given. Application also includes solidification of casting. An increased interest in the heat-transfer problem involving a change of phase has been developed in recent years. Practical problems include solidification of a casting, freezing and thawing of soil, ice formation, and others. Despite the importance of the topic, a literature search reveals relatively few solutions which may be extended to practical problems. Due to mathematical complexity, which comes from the nonlinearity of governing differential equations, exact analytical solutions which have been published are limited to a few cases with simple boundary conditions. Although numerical solutions of these problems have become available after highspeed digital computers were introduced, lack of simple and general methods of programming for computation makes this approach impractical. The case of the semi-infinite slab with constant surface temperature was solved in the 19th century. In honor of Neumann, who first found an analytical solution, this kind of problem is generally referred to as the Neumann solution. As has been shown in Fig. 1, the problem to be analyzed is the freezing of a semi-infinite region (x > 0) which is initially liquid at the melting temperature with the surface (x = 0) maintained at time-dependent temperature. This analysis can be applied to the study of many casting processes where most of the heat removal is essentially unidirectional. "Heat balance integral" which has been used by Goodman1 is employed in this analysis. The concept of "heat balance integral" is to define a quantity, d(t), called the thermal layer. Beyond this thermal layer, for all practical purposes, there is no heat transfer, and the region is at the equilibrium temperature. "Heat balance integral" is obtained by integrating the conduction equation with respect to the space variable over this thermal layer d(t). Choosing some plausible temperature distribution, usually a polynomial or a finite trigonometric series in the space variable, this integral equation becomes an ordinary differential equation, with time as the independent variable, which can be solved by classical methods. The thermal layer and "heat balance integral" are equivalent, respectively, to the boundary-layer thickness and the momentum integral in hydrodynamics. A modern account of Prandtl's concept of the boundary layer and von Karman's momentum integral may be found in Ref. 2. Although the problem considered here has been limited initially to uniform melting temperature, the present method is equally applicable to the case with arbitrary temperature distribution in the liquid. STATEMENT OF THE PROBLEM The physical situation and coordinate system used in the problem to be analyzed are shown in Fig. 1. Notations used are listed in the table of nomenclature. Let us assume a semi-infinite region extending over positive x, initially at the uniform melting temperature. At the surface x = 0, a time-dependent temperature, which has a numerical value

Jan 1, 1965

By N. Krauland, A. Nystrom, M. Board, S. Sandstrom

Several deep Swedish cut-and-fill mines experience severe ground control problems, including roof collapse and wall sloughing, as a result of variable rock quality and high in situ stresses. A project to examine the problem included two main areas. The first was prediction of mining conditions at depth and the adaptation of cut-and-fill mining to such conditions; the second was the assessment and improvement of support methods at present and future depths. Simple, elastic, mine-scale numerical models were used to optimise stope sequencing and more detailed, stope-scale models to simulate the failure processes around a stope and the interaction of rock mass and support. Kristineberg was chosen for testing and calibration of the predictive methods because of its long history of severe ground conditions and the large base of observational and monitoring data available for comparison. Horizontal cut and fill was found technically suitable to depths beyond 1 000 m and economically viable if ore value covers support costs. Stability can be achieved with the present support technology down to 1 000 m but the 7-strand 15.2 mm cables have poor deformation properties (5% failure strain) compared with rebar rock bolts (17%). Reducing the intervals between levels from 100 m to 50 m will cut support costs and improve production reliability and capacity. Simulation of sill-pillar mining indicated that conditions would be most severe when pillar height was reduced to 15-20 m; mining of a sill pillar has been carried out successfully to the last 3 m, whose extraction is planned for the near future

Dec 1, 1995

By M. A. Vasina, I. A. Matveeva, E. A. Naumova, V. V. Doroshenko, N. A. Belov

"Using the calculated (Thermo-Calc software) and experimental methods (SEM, TEM, EMPA, DSC, XRD, etc.) the phase composition, structure and hardening of aluminium alloys of the Al-Ca-Zn-Mg system were studied in the following range: 2. 5%Mg, up to 10% Ca, and up to 14% Zn (wt%). Fragments of this quaternary phase diagram in the aluminium corner were constructed, including the liquidus surface, as well as some vertical sections. It was shown that the relatively large amount of zinc enters in the Ca-containing phase, which formula can be described as (Al,Zn)4Ca. An increase of Zn content leads to formation of Al4Ca primary crystals at lower concentrations of calcium. The eutectic (Al)+(Al,Zn)4Ca has a fine structure and aluminide particles are capable to spheroidization during the heat treatment at temperature 500 C. The maximal level of hardness observed on calcium containing alloys was higher than 200 HV, what gives the reason to expect good strength properties. With an example of an Al-9% Zn-2,5%Mg-3,5% Ca model experimental alloy based on the (Al)+(Al,Zn)4Ca eutectic, a principal possibility of manufacturing thin rolled sheets was demonstrated.INTRODUCTION Aluminum alloyed with calcium was first studied in 1970-80s by such authors as Piatti (1976), Moore (1978, 1980), Il'enko (1985), Swaminathan (1990), and Perez-Prado (1997) as superplastic materials. In particular, the alloy systems Al-Ca-Zn were studied (Il'enko, 1985, Swaminathan, 1990, Perez-Prado, 1997). For some time there was no new published works concerning the aluminum-calcium alloys. During the last years many works were published dedicated to the calcium alloying of magnesium alloys (Kim, 2011; Xu, 2011; Aljarrah, 2008; Bakhsheshi, 2014). This urged the authors (Belov, Naumova & Akopyan, 2016) to start studying cast and wrought aluminum-calcium alloys for construction (2008–2014). There is almost no information in the literature concerning triple and more complex diagrams of the aluminum-based system states with calcium and other elements. In recent work, parts of the state diagrams are plotted for the aluminum angle zone: Al-Ca-Mg-Sc (Belov, Naumova & Bazlova, 2016), Al-Ca-Ni-Sc (Belov, Naumova & Bazlova, 2017), Al-Ca-Si-Sc (Belov, Naumova & Akopyan, 2017) and others. Special attention was paid to the study of the system Al-Ca-Zn-Mg (Naumova, 2017). Based on this system creation of advanced extra-high tensile alloys is planned. Wrought extra-high tensile alloys series 7??? based on the system Al-Zn-Mg-Cu are well studied."

Jan 1, 2018

By Shobhana Dey

A low volatile medium coking coal from Jharia coal field, India was used for this investigation. The proximate analysis of the sample shows that it contains about 25% ash, 21.4% volatile matter and 52.4% fixed carbon. The sizewise ash analysis of -0.5 mm coal indicates that -0.5+0.15 mm fraction contains lower ash (21.9%) than -0.15 mm fraction (29.7%). The flotation characteristics of the -0.5 mm coal were determined by release analysis. The study reveals that recovery of combustible at 15% ash is about 27% and 43% at 17% ash level. The low recovery is due to the presence of high ash in finer fraction. In order to improve the recovery, the -0.5 mm feed was classified into -0.5+0.15 mm and -0.15 mm fractions, and subjected to flotation separately. The recoverable combustible obtained from the release analysis of -0.5+0.15 mm at 15% ash level is 46%. The effect of collector dosage, frother dosage and aeration rate on flotation was studied. The responses of these variables in collectorless flotation of the -0.5+0.15 mm fraction containing low ash were also studied. A lower aeration and frother dosage favored the generation of clean coal with low ash. The ash content in the tailing stream from -0.5+0.15 mm flotation circuit is close to that of the original -0.15 mm fraction. The former is ground to -0.15 mm and the two fractions are processed together. As -0.15 mm fraction contains relatively higher ash, collector aided flotation using sodium silicate was performed to recover the clean coal with 17% ash. The products of the overall flotation circuit having different ash levels were recommended for use in different applications. The reject from -0.15 mm flotation circuit contained 56.4% ash which can be used for fluidized bed combustion (FBC). This eventually leads to complete utilization of coal.

Sep 1, 2012

By Ellis S. Hertzog

The relatively large amount of phosphorous occurring in many iron ores limits their usefulness aid sometimes renders them valueless under present conditions of nip-iron manufacture. A practical method for removing the phosphorus would be valuable to the iron and steel industry. Gravity concentration has been of little value as far as the removal of phosphorous is concerned, because the compounds of this element are, as a rule, disseminated very finely. Removal of the phosphorous by leaching is not a new idea and has been the subject of some investigation,3,4/ out for data :lave been published. W.R. Crane published analyse of various ore bodies in the Birmingham ham district. The hard or unleached ores a .re much higher in phosphorous than the Soft, leached ores along the outcrops. This fact indicates that as mild a leaching agent as water removes phosphorus effectively if enough time is allowed for it to react. As the forms in which phosphorous occurs in the iron ores are important in the consideration of any leaching operation, much time was expended in devising a method for determining them. According to Professor McVey, University of Alabama, the phosphorous-bearing minerals in the red iron ores of Alabama have not been positively identified by any microscopic methods.

Jan 1, 1935

By Gordon R. Wicker, Peter V. Avotins, Steven S. Ahlschlager

Laterite ore slurries exhibit Bingham plastic behavior and can be characterized by the magnitude of their yield point and Bingham viscosity. These two parameters are affected by ore composition, solids concentration, and temperature and are used to predict the pressure drop in pipelines and heat transfer coefficients in shell-and-tube heat exchangers. In cycloning of laterite slurries, the calculated cut size is corrected by factors obtained from the rheological parameters.

Jan 1, 1979

By Stuart M. Buck, J. H. Bramwell, Edward H. Williams

The Southwest Virginia Improvement Company began operations in the Bluestone Flat-Top coal-field, situated in Tazewell County, Virginia, in the fall of 1881. In May, 1883, the company had built 200 coke-ovens, and by March, 188-1, had 9000 feet of entries, exclusive of air-ways, in the Nelson or Rig coal-bed of this district (which here averages eleven feet in thickness), and had extracted 200,000 tons of coal, representing an area of about twenty acres. About this opening has grown the recently incorporated city of Pocahontas, and the completion of the New River branch of the Norfolk and Western Railroad to this point enabled the company to make large contracts for supplying coal and coke, so that it was deemed necessary, on account of the limited area developed, to work the mine day and night to fill orders. At 1.30 Thursday morning, March 13th, the inhabitants of Pocahontas were awakened by a violent shock, and within a few minutes all knew that the East mine had been the scene of an explosion of so general a nature that, of the 114 men at work, not one had escaped. The daily papers gave more or less distorted accounts of the number of victims, the scenes in and about, the mine, and the probable cause of the disaster. At the request of the company, the President of the American Institute of Mining Engineers appointed the undersigned a committee of three to investigate the matter, and the committee thus constituted presents the following report, accompanied by a copy of the testimony taken daring the investigation, for preservation in the archives of the Institute. Pocahontas was reached on Thursday, April 24th, and left on Friday, May 2d. During this interval the committee made repeated visits to the mine, especially to the points, of most importance, examining it carefully in every part; and summoned a number of witnesses, twenty-six of whom appeared and testified. The mine had been left in the same state as when the bodies were

Jan 1, 1885

By Do-Hyeong Kim, Jong-Jin Pak, Jung-Mock Jang, Min-Kyu Paek

"Thermodynamic relations among Mn, Al and N in liquid iron were studied by measuring the effect of Mn on the solubility product of AlN in liquid Fe-Mn-Al-N alloys in the temperature range from 1773 to 1873 K. The critical Al and N contents for AlN formation were determined by the metal-nitride-gas equilibration technique over wide ranges of melt composition and temperature. The effects of Mn on N solubility in Fe-Mn and Fe-Mn-Al melts containing Mn up to 26 mass% were separately determined in the same temperature range. The experimental results were thermodynamically analyzed using the Wagner's formalism to estimate the critical Al and N contents for the onset of A1N formation. The validity was checked by the observation of inclusion evolution in Fe-20%Mn-1.5%Al-0.6%C-0.3%Si-0.012%N melt during cooling and solidification.IntroductionRecently, high manganese steels such as Twinning Induced Plasticity (TWIP) steels have been developed as next generation steels because of their high formability as well as excellent strength and ductility.[1•2l In these steel grades, a large amount of Mn (15-20 mass%) and Al (1-2 mass%) are added to liquid steels, and such high Mn and Al concentration bring the great challenges to the steelmaking and casting processes. Mn significantly increases the N solubility in liquid iron and the AlN inclusions can be easily formed at such high Al concentrations due to high affinity of Al and Mn with N in liquid steels. Although the AlN inclusion is known to be a dominating and considered as a detrimental phase for the hot ductility of steels,l3l thermodynamics of AlN formation in high Mn-Al alloyed liquid steels was not well known.Moreover, the melting point of these steels decreases down to near 1623 K as increasing Mn content up to 20 mass%. However, most of thermodynamic data has been measured at the steelmaking temperature around 1873 K. Even at steelmaking temperature, there are huge scatters in thermodynamic interactions of Mn and Al on N in liquid iron. The nitrogen solubility in Fe-Mn alloy melts has been measured using the Sieverts' method[4l and the samplinij method[5-7J in the temperature range of 1813 to 1973 K. In the authors' recent study,[8•9 the N solubility in Fe-Al alloy melts was measured using the sampling method in the temperature range of 1823 to 1973 K. However, the simultaneous effect of Mn and Al at high concentrations on Nin liquid Fe-Mn-Al-N alloys is still not known. Also, there remains uncertainty about the temperature dependence of the interaction parameter of Mn on N in liquid Fe-Mn alloys. Therefore, it is worthwhile to check the temperature dependence of this parameter at a low temperature near the melting point of Fe-Mn alloys. There have been few studies on the characterization of non-metallic"

Jan 1, 2014

By J. Halpern, D. R. McKay

SOME of the most important hydrometallurgical developments in recent years relate to processes involving the oxidation of sulfide minerals in aque- ous suspension at elevated temperatures by air or oxygen under pressure. Among these is the acid pressure-leach process which has been developed, particularly for the treatment of pyritic uranium ores.1-5 In this process, an aqueous suspension of the ore is digested in an autoclave, in which an overpressure of air or oxygen is maintained, at temperatures above 100°C. Oxidation of the pyrite (FeS,)

Jan 1, 1959

By Frank Firmstone

WE found it necessary, in December, 1874, to repair the upper part of the lining in No. 5 furnace at Glendon, and, as we succeeded in doing it with comparatively little trouble, a description of the plan followed may be of service to those having a similar operation to perform. On two opposite sides, as shown by the sketch, the lining was completely gone for a height of about four feet, below which it increased gradually in thickness, being nine inches thick about three feet lower down. On a plane at right angles to the section drawn, the brick were nowhere entirely gone, but were in some places not more than two or three inches thick, being still sufficient to sustain the upper part, where the brick, being above the level of the stock, were not at all worn. The furnace was blown down, so that when we cast and closed the tuyeres, about 7 A.M., on December 8th, the top of the stock was about twenty-four feet below the filling-plates. The walls were quite hot, and a good deal of gas was given off for several hours after the tuyeres were closed. The hopper and bell were thrown into the furnace, and were covered by filling several charges of cold stock over them, which at once greatly cooled off the top of the furnace. A wrought-iron pipe, thirty inches in diameter, in five sections, each six feet long, was then put down, and made to stand upright, as nearly as possible in the centre of the furnace. Around this we filled a double charge of coal, taking care to heap it up next the pipe, and let it get thinner as it got to the walls. This was covered with about two feet of fine ore, leaving the lowest joint in the pipe entirely uncovered. We were now ready to put in our scaffold to get at the

Jan 1, 1876

By V. Ramachandran

The Amarillo Copper Refinery, the newest and most modern copper refinery in the world, has been in operation for the last eleven years and has a rated capacity of 460,000 st/yr. The tankhouse - a structure that covers 500,000 ft2 under one roof - extends one-half mile in length and is a model of materials-handling efficiency. The use of recently developed and patented* reagent control technology, termed "Reatrol Process", has increased current efficiencies to an average of 98% and has considerably improved the physical and chemical quality of the cathode deposit. The present paper describes the current operations at the Amarillo Copper Plant with special emphasis on tankhouse operation.

Jan 1, 1987

By T. S. McGahey

The southeastern region of the United States has long been a major market area for coarse and medium particle size natural ground calcium carbonate fillers. The primary market for calcium carbonate in the southeast traditionally has been as fillers in building materials such as carpeting, joint cement and roof shingles. In these applications the economic value of the calcium carbonate in the final product is weighted more toward lessening the cost of the final product, as opposed to contributing any desirable physical characteristics. For example, in carpet backing applications the calcium carbonate filler does little more from a physical standpoint than add weight and body to the backing adhesive. The important factor in the use of calcium carbonate in carpet backing is that it can be used at high loading levels to replace the more expensive latex binder, thus lessening the cost of the final product. It is estimated that calcium carbonate producers in the southeast sell in excess of 200,000 tons (181,436,000 kg) annually for use in latex compounds for carpet backing applications.

Jan 1, 1986

By A. V. Deforest, A. R. Anderson, C. W. MacGregor

ONE of the important problems in the design of structures and machine parts subjected to rapidly applied loads is the determination of the strength and ductility of the material itself under such conditions. Realizing the need for such information, many investigations have been carried out in the past. Most of these experiments have been made using notched bars in bending either with the Charpy or Izod impact machine. While yielding valuable data on the effect of notches in the energy absorption of the material and on the condition of heat-treatment, this form of test does not lend itself readily to a determination of fundamental stress-strain relations. For this and other reasons, more attention has been paid recently to the tension impact test. An extensive literature already exists on the subject and only those investigations somewhat closely related to the present paper will be mentioned. For a more comprehensive list, the reader is referred to the Symposium on Impact Testing of the A.S.T.M., 1938. The work of Mann,1 Clark and Dätwyler,2 Nádai and Manjoine,3 Winlock and Leiter,4 Deutler,5 and Brinkmann,6 however, deserve especial mention. In most of the previous investigations on the subject, when stress-strain relations were obtained under high rates of loading, it was the common procedure to determine stresses based on the original area and strains based on the original length. Stress-strain curves were then constructed by [P OL, plotting So = Ao as a function of eo = Lo] where A o and Lo refer to the original area and gauge length, respectively. At present there exists a paucity of true stress-strain data in the impact problem. The advantages of constructing so-called true stress-strain curves in order to reveal the fundamental physical properties of the material for the tension test were discussed recently by one of the authors' It was shown that the true physical behavior of the material in the tension test could best be represented [by plotting the average true stress, S = P as a function of e = q' = log o = log Log] where P, A, L, S, e, and q' refer to the load, the cross-sectioned area while the load P is applied, the actual gauge length, the average true stress, the true strain and true reduction in area, respectively. Besides giving a better physical representation, the method has certain additional advantages in that the stress-strain curve so plotted becomes a straight line from the maximum load point to fracture. The construction of such- curves, however, while comparatively simple for the slow rates of loading customarily used in the tension test, presents certain difficulties for tensile impact in that both loads and diameters are required throughout the test. The continuous measurement of test-piece

Jan 1, 1941

By D. M. S. Bhatia

The intimate association of iron formation and massive sulfide deposits has been documented by many investigators (McAllister, 1960; Hutchinson, 1972). In a classic example of such an association four distinct facies (oxide, carbonate, silicate, and sulfide) were identified in an Algoma type iron formation occurring in Paleozoic rocks, but exhibiting physical features (banding) and chemical composition (SiO2 + A1203 + Fe2O3) typical of Precambrian iron formations. The geochemical variation of the iron formation was studied by analyzing 62 samples for Si, Al, Fe, P, S, and CO2. Following a model proposed by James (1954), the geochemical and mineralogical variation of the iron formation can be used as an excellent tool for the exploration of massive sulfide deposits.

Jan 1, 1981

By Michel G. Grenier

Compliance with Diesel Particulate Matter (DPM) exposure regulation is currently performed using timeweighted average (TWA) sampling on underground mine workers. These samples are collected in the span of an entire shift and the resulting concentrations are compared to a legislated exposure limit. While this is very useful to determine the exposure level of an individual to DPM, it fails to clearly identify causes of exposure and highlight opportunities that could help reduce the exposure of workers in the course of the work shift. Real-time DPM monitoring measures the worker?s exposure as a function of time and helps identify circumstances where corrective actions can be taken or design changes can be made by the individual or the employer to reduce the overall exposure of the worker and peers. This work focused on obtaining DPM concentrations using a real-time polycyclic aromatic hydrocarbon (PAH) monitor. The aim was to demonstrate that this instrument, while not a direct DPM analyzer, was able to provide a concentration profile that could easily be linearly correlated to standard TWA elemental carbon measurements. In addition, several instances of improvements that could be implemented to reduce the exposure of underground employees were demonstrated.

May 1, 2010

By S Basu, P M. Midhun

Electro-Slag Remelting (ESR) is a process capable of producing ingots with much lower centre-line segregation and better internal soundness than conventional ingot casting processes, as well as lower inclusion and sulfur concentrations. This process is commonly used for alloyed steels intended for critical applications like components of marine turbines, supercritical powerplants and rocket motor casings. It involves melting a metal electrode using electrical resistive heating in a slag pool and re-solidification of the resulting metal droplets beneath the slag layer, forming an ingot. Conventional ESR fluxes consist primarily of CaF2, Al2O3 and CaO, along with minor concentrations of SiO2, MgO etc. The emission of fluoride vapour from the molten slag causes several environmental and health problems, triggering a need to develop and reduce the fluoride content in the ESR flux. The present study aims to develop low-CaF2 alternatives to commercial ESR fluxes without compromising on productivity and the surface quality of the refined ingot. Thus, the modification in chemical composition needs to satisfy properties like electrical resistivity, viscosity and liquidus temperature, essential for efficient ESR operation. Since electrical resistivity and viscosity are highly dependent on the ionic structure of the molten slag, it is important to understand the effect of compositional modification on the structure of the flux. The present study employs Fourier-transform infrared spectroscopy (FT-IR) and Raman spectroscopy to investigate the structural variations in the modified fluxes, especially the effect of changing SiO2 concentration, in comparison with conventional CaF2-rich fluxes. Additionally, thermal analysis (Differential Thermal Analysis (DTA) and Thermogravimetric Analysis (TGA)) has been carried out to characterise the melting behaviour of the fluxes. The findings are compared with simulations carried out using the FactSage™ software, ver 8.3 (GTT Technologies, Aachen, Germany). Simultaneous analysis of liquidus temperature and the structure is expected to help in identifying the practical suitability of modified ESR flux compositions for industrial implementation.

Jun 19, 2024

By L. V. Clark, Arthur La Motte

"INTRODUCTION The U. S. Bureau of Mines in 1930 and 1931 made a study of the properties and characteristics of liquid-oxygen explosives (L.O.X.) at the request of one of the largest users, in order to determine and eliminate the hazards attending its use.This report deals with the examination of absorbents for L.O.X. to (1) determine their most desirable and most undesirable characteristics, (2) to find ways and means of desensitizing absorbents to mechanical shock, and (3) to determine the effect that such desensitization of absorbents has on the explosive Characteristics of L.O.X.ABSORBENT MATERIALS The absorbent used in driving the Simplon Tunnel, the earliest project in which L.O.X. was used, was composed of crude petroleum, soot, and kieselguhr. During the World War, powdered cork, soot, sawdust, powdered straw, or other similar powdered materials were mentioned in the German military instructions for use of ""liquid air"" explosives. At that time the common types of absorbent, materials were compounded ones containing the above ingredients as well as kieselguhr, paraffin, gas oils, charcoal, bituminous coal, etc.Kuryla and Clevenger4 investigated absorbents of the above type and made the following statement concerning them:"

Apr 1, 1932

By Virtanen M

Grinding has been one of the areas of major development at Outokumpu's concentrators. During its early years the company used entirely rod and hall mills, but due to the high costs of metallic grinding it began the testing of autogenous grinding as early as the 1950s. In the late-1970s, the company's own modification for two stage autogenous grinding was ready for industrial use. Surprisingly late, in the 80s - 90s, an interest rose to check also the effects of grinding methods on flotation results. This paper firstly gives a short history of the development work of Outokumpu type autogenous grinding, called 'Outogenius'. The effects of some grinding methods on the process results of two nickel ores are then reviewed. The tests to date show notable effects of grinding methods on flotation.

Jan 1, 1996

By Paul J. Axtell

This case history describes the foundation design and construction for the New Mississippi River Bridge, presently under construction in St. Louis, Missouri. The 1,500 ft (457.2 m) main span of the cable-stayed bridge is supported by two delta tower pylons in the river, with anchor piers on each bank. The final foundation design was completed as a part of an Alternate Technical Concept (ATC) proposal by the winning construction team, and utilized drilled shafts up to 11.5-ft (3.5-m) diameter that were socketed into very hard limestone. As part of the ATC foundation design, a full-scale, bi-directional static load test was performed to verify the design and allow use of higher resistance values. This paper presents the results of the site exploration, construction of the load test shaft, details of the load testing, and a comparison of the test results with various design parameters.

Jan 1, 2011