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Stope back conditions in the cut-and-fill stopes at New Broken Hill Consolidated Limited often deteriorate to such an extent that, because conventional rockbolts are not able to maintain safe working conditions, square-set timber is installed. An attempt to eliminate this costly procedure has involved the use of long grouted rockbolts using high tensile prestressing wire. These bolts were developed in conjunction with the prestressing engineers of BBR (Aust.). This form of support has improved the back conditions, maintained safe working conditions, and delayed the introduction of timber in a number of stopes.Production from these stopes has been maintained at its previous level (at a rate approximately double that of a comparable timber stope).

Jan 1, 1974

By Silvana Costa

In the last two decades, there have been nearly no new mining towns built in Canada. Governments and mining companies have viewed long distance commuting (LDC), commonly known as fly-in-flyout or fly-in mines, as a way to avoid problems associated with building a new community and providing for its sustainability after mine closure. LDC is also considered more cost-effective than building a mine town. The intensification of the use of LDC in the Canadian mining sector has been quite rapid, particularly in northern regions. However, LDC has implications to employees, their families and communities, which deserve further examination, particularly considering the significant expansion in Northern mining and Aboriginal participation in this sector. This paper presents a review of the major issues in long distance commuting, both from an industry and community perspectives. It is a result of preliminary investigation for a PhD research project that will be pursued by a Bridge Fellow and UBC Mining Sustainability Working Group member, and guided by an interdisciplinary research team at the University of British Columbia (UBC). The Bridge Fellowship Program is research-training program linking the UBC?s Faculties of Medicine, Engineering and Graduate Studies. Its mission is to develop creative evidence-based prevention measures for public, environmental and occupational health problems. The SWG is an interdisciplinary student group based in the UBC Department of Mining Engineering, committed to respond to the complex sustainability-related challenges currently faced by the mining industry. In other to pursue this project, it is paramount that industry and local communities alike participate in the development and clarification of research questions as well as in the research design. It is hoped that this paper will function as an invitation for industrial and community partners for such study. The main themes identified for this research are occupational health and safety of LDC employees, family life impacts and community health impacts of this model of resource development.

May 1, 2004

By J. R. Thoenen

Occurrences of titanium, zircon, and other heavy minerals are widespread in Florida. Deposits concentrated as "heavy sands" by wave and wind action have been mined an or near Atlantic coastal beaches since 1916. An important inland concentration at Trail Ridge; .believed, to have formed along an ancient share line, was disclosed by preliminary investigations (1947) by the Bureau of Mines. This report describes investigations to determine the extent and grade of "heavy-sand" concentrations in other inland stabilized dune areas in the central and northeastern parts of the peninsular region of the State (fig. 1). Portions of the central highlands south of Trail Ridge and terraces and dunes in the coastal lowlands region, east and northeast of the ridge were investigated. Holes were drilled in 10 areas (see table 1 and fig. 2) along State and County roads and on private property. They were spaced 250 to 2,000 feet. apart to obtain a cross-sectional picture of "heavy-sand" content in the dune areas. These sections were generally placed in east-west directions normal to the general trend Of the peninsula to intercept one or more of the ancient shore lines in the various areas (figs. 3 to 13, incl.). A total of 433 drive piped and 333 jet holes were drilled, and 7,293 bulk and core samples were taken. Intermediate holes were placed at closer intervals when field analysis indicated 1 percent or more of heavy minerals present. All of the holes drilled and the analysis of samples that contain 1 percent or more of heavy minerals are listed in table 2. Profiles (figs. 14 to 20, inclusive) show the more favorable concentrations, which are irregular in outline and erratic in mineral content. The highest concentrations averaged 1.0 to more than 2.0 percent heavy-mineral content, but a few individual hole samples exceeded 3.0 percent in grade.

Jan 1, 1949

By Jannie van Deventer

"Innovation in the minerals industry has been lagging behind comparable industries like oil and gas. An incremental innovation culture that tolerates long lead times between invention and adoption has been exacerbated by a research grant structure that inhibits radical idea generation. Entrepreneurs who can make the link between ore source, technology and finance will cause a shift in innovation culture and open up substantial opportunities in the minerals industry of the future. By extrapolating existing trends in technology within and outside mineral processing, a crystal ball vision of future innovation is shaped with the aim to lower energy and water demand, reduce CO2 emissions, decrease operating and capital costs, reduce environmental impact, and secure a social licence to operate. Advances in nanotechnology, advanced materials and biotechnology will impact mineral processing, but the initiative for technology transfer must come from mineral processors. Laminates of graphene oxide can offer efficient filtration and separation media, while microfluidic devices will be used for desalination, solvent extraction and analysis. Substantial progress is expected on benign lixiviants and separation agents, such as nanoscale supramolecular hosts that can serve as high-capacity, selective and recyclable ligands and sorbents, and solid aminobiphosphonate-based adsorbents. Radical ideas for the recovery of precious metals from non-assayable ores and the generation of energy above unity will be adopted in selected minerals projects. In-situ mining in which microbes generate lixiviants at mineral surfaces will simplify processing circuits. Specific ores will be subjected to microwave processing and electropulse liberation to enhance recovery. Ultrafine grinding using devices of low energy consumption will be done mainly dry, followed by dry separation. New flotation cells will remove efficiently either coarse particles or ultra-fine particles, with mineral surfaces being modified not just by new reagents but also by selective microbes. Innovation in mineral processing indeed has a bright future."

Jan 1, 2014

By D. J. Thorkelson

New data indicate Wernecke Breccia-associated iron oxide copper-gold (IOCG) deposits likely formed from moderate-temperature, high-salinity, non-magmatic brines. The breccias formed in an area underlain by a sedimentary sequence that locally contained evaporites (potential source of chloride and possibly sulfur) and was thick enough to produce elevated fluid temperatures. Metals (Fe, Cu, Co, U) were probably derived from host strata, transported as chloride complexes, and precipitated due to changes in fluid temperature and pressure during brecciation. These new data suggest that the spectrum of genetic models for IOCG deposits that typically invoke formation from magmatic or hybrid magmatic-non-magmatic fluids should be expanded to include those systems that formed in a non-magmatic environment. Modifications to the definition of IOCG systems are proposed that reflect the degree of involvement of magmatic and/or non-magmatic fluids and the nature of the mineralizing environment. A division into magmatic, non-magmatic, and hybrid magmatic-non-magmatic IOCG types is suggested. Typical magmatic end-member IOCG deposits include Lightning Creek and Eloise, Australia. Hybrid magmatic-nonmagmatic IOCG examples include Ernest Henry and Olympic Dam, Australia. The Wernecke Breccia and Redbank deposits are suggested as possible representatives of non-magmatic IOCG end members. Endmember magmatic IOCG deposits have similarities to some porphyry deposits, whereas non-magmatic IOCG end members share characteristic with some sediment-hosted Cu deposits, suggesting that the range of IOCG deposits may form a link between intrusive- and sediment-related deposits

Jan 1, 2007

By Fred C. Schmednecht

For years, the strategy was to contain waste and in many applications, is still the recommended method. Recently, it has become acceptable to create filters below ground for the in-situ treatment of waste. Consequently, in lieu of the waste being contained, it is desirable that the waste flow through a pervious treatment zone. For instance, subterranean pervious walls comprised of iron sand are particularly useful in treating chlorinated solvents in contaminated groundwater. The iron acts as a corrective filter to treat the contaminated groundwater. How are these impervious and pervious walls being constructed? One effective means of constructing an impervious barrier is the vibrated beam method. This method, in brief, involves the use of a fabricated steel beam, a vibrator, a pile driving crane, and a mixing plant. This method results in a 4-6" wide wall with depths up to and exceeding 100'. Over one hundred slurry walls have been installed using this method in the United States. The need for the vibrated beam method continues to escalate due to its reduced health and safety considerations, high level of quality control, lack of excavation, narrow working area, and ability to achieve depths greater than 100'. A recent project was in Marinette, Wisconsin at the ANSUL facility. The project consisted of a 28,000 square foot slurry wall and was completed in January of 1999. Another effective means of creating an impervious barrier, where structural support from the barrier is needed, is the Waterloo® Barrier System. This system involves the use of a pile driving crane, Waterloo® steel sheet piles which are patented steel sheet piles due to their groutable interlocks, and a grout plant. This system results in a water-tight barrier due to the grouted interlocks and provides structural support. A project was completed at Beta Steel in Portage, IN for a retention pond to protect Lake Michigan. Due to the new concept of "filtering", there are few accepted construction techniques available. One effective field proven construction technique is the patent pending mandrel emplacement technique. This technique involves the use of a fabricated hollow steel mandrel with a shoe, a vibrator, a heavy duty crane, and a material feeder. This technique results in a pervious wall which may be comprised of pure iron sand or any other flowable media. Using this technique, the pervious wall may be constructed in varying widths to depths in excess of 100'. A successful installation occurred in October 1997 at Cape Canaveral Air Station in Florida.

Jan 1, 1999

The Torington Lodes.This paper describes investigations into mineralogical, petrological and structural associations of cassiterite in occurrences of economic value. The work was carried out in three mines, during a number of years, in the hope that the, data collected might be helpfulin the search for occurrences of cassiterite in stanniferous zones and reduce unproductive exploratory work. Tin-bearing lodes at Torington, in the New England district, New South Wales, have been worked since 1880, and the locality is the most important centre of lode tin occurrence in the, State. The township of Torington is 18 miles westerly from Deepwater, a station on the Great Northern Railway, 446 miles from Sydney.The tinfield forms part of the Mole Tableland, which has an altitude between 3,000 ft. and 4,000 ft. above sea level. The country rock, in which the stanniferous lodes occur, is granite of Permian age, which has been intruded into Carboniferous claystone. An inlierof claystone is exposed to the west of the stanniferous area, 'and in it, close to' its contact with the enclosing granite, are occurrences of wolfram and bismuth. These minerals, together with chalcopyrite, pyrite, arsenopyrite, zinc blende, galena and molybdenite, in very small quantity, are associated with cassiterite in lodes traversing the granite, particularly near the claystone, but decrease in amount with distance from the contact. Their occurrence is sporadic and usually causes no trouble in dressing the cassiterite concentrate, the final product containing less than 1% of total penalisable impurity. In Curnow's mine, pyrite, galena and molybdenite have been observed at 700 ft. from surface.The granite is of the biotite type and its structure may be divided into four groups, or classifications, arising from segregation processes during cooling and consolidation. The four classes, in order of extent of distribution, are:1. Granite of normal type, in which the constituent quartz felspar and mica, have a particle size approximately 14, in.2. Porphyritic granite, in which the felspar particles are from % in. to lin. in size, that of the quartz and mica approximately % in.3. A fine-grained granite, in which the particles of all constituent minerals are % in. or less in size;4. A rock of highly siliceous ground mass containing very small particles of felspar and almost negligible biotite.Type 1 is the general type of granite in all mines of the field; types 2 and 3 may occur as large masses, or all three classes may merge rapidly one into the other, and all be disclosed in 20 ft. of driving. Usually, however, the segregations are massive, but are not associated with any special horizon. For instance, a mass of porphyiiticgranite extends from surface to a depth of 440 ft., for a distance of 350 ft. south from the New England main shaft. The upper levels of Curnow's mine, 14" mile south-east, are in normal granite, but a restricted mass 'of porphyritic granite occurred between Nos. 5 and 6 levels, or 400-500 ft. below the collar of the shaft...

Jan 1, 1950

By C. -T. Mutale, A. S. Tuling

Titanium can exist in three different oxidation states. Its oxides are numerous and in presence of iron and oxygen, iron-titanium oxide compounds can also form. Some of the oxides are non-stoichiometric, making the determination of the thermodynamic properties of titanium and its oxides in molten steel and in slag difficult. Therefore, for the assessment of titanium activity in molten steel using the electrochemical measurements of oxygen partial pressure, the identification of oxides in equilibrium with titanium is important. This paper reports on an investigation of solid titanium oxide inclusions, which have been identified by combining different methods of analysis on quenched samples. These samples were taken from a Fe-Ti-melt at 1600°C, quenched in cold water then mounted and polished for optical microscopy. The oxide inclusions were analysed using transmission electron microscopy (TEM) with energy dispersive spectroscopy (EDS). Both single crystal and polycrystalline diffraction patterns were used to identify the oxides by comparing the d spacings with those in the ICDD X-Ray Diffraction (XRD) database. XRD was used to analyse the oxide particles on the top of slow cooled samples. It was found in the TEM study that the similarity of the diffraction patterns of the various phases meant that unique identification was difficult to achieve in some of the diffraction patterns. However, TiO, Ti2O3, Ti3O5, Ti4O7were identified in quenched samples, while TiO2, FeO.TiO2and iron oxides were seen in slow cooled samples. It was also confirmed that the type of oxides is related to titanium content of the samples. Keywords: Titanium, Titanium Oxides, Iron, TEM, XRD, thermodynamic.

Jan 1, 2004

By David A. Andrews

Coal occurs at many scattered localities in Arizona, California, Idaho, Nevada, and Oregon, but in most of the known occurrences thick coal beds are of small extent and the coal generally contains a high percentage of impurities. The coal beds occur at many different horizons in strata of Cretaceous and Tertiary age. Bituminous coal has been found in several areas, the most extensive of which is the Eden Ridge field of Oregon. Lignite also occurs in many places, but the only extensive deposit is in the Goose Creek field of Idaho, Nevada, and "Utah. The coal reserves of the region are largely of subbituminous rank; most of the subbituminous coal is in the Black Mesa field of northeastern Arizona and the Coos Bay field of Oregon. The Black Mesa field contains more than 80 percent of the coal reserves of all ranks but is remote from both transportation facilities and centers of consumption. Substantial reserves ill the Coos Bay field are favorably situated with respect to transportation and markets. ARIZONA Subbituminous coal occurs in the Black Mesa, Pinedale, and Gallup coal fields in Apache, Navajo, and Coconino Counties, Ariz. (fig. 1). Bituminous coal occurs in the Deer Creek field in Pinal and Graham Counties and in a small area in Apache County at the north-east corner of the State. All the coal beds are in strata of Cretaceous age. The coal in the Gallup field and at the northeast corner of the State lies in the Western edge of the San Juan structural basin. "Vest and south of this basin the coal-bearing strata have been removed by erosion except in high mesas.

Jan 1, 1947

By Kouichi Tomisawa

Two bridges were constructed for extension work of Central Hokkaido Connection Road in 2005 at two different sites. Pile group foundations were employed for the foundations of abutments of the two bridges. In order to assess the performance of the constructed piles in the sites and to obtain design parameters for design in future, static alternating cyclic horizontal load test was carried out on one of the open-ended steel pipe piles constructed at each site. The ground at one site was characterised as a thick deposit of volcanic soils, and the ground at the other site was characterised as a very soft peat layer near the surface. In this paper the results of static alternating cyclic horizontal load tests on the piles at the two sites are presented and discussed in detail.

Jan 1, 2006

By Jean R. Garcia, Paulo J. R. Albuquerque, Renato P. Cunha, Osvaldo Freitas Neto

"Abstract Results obtained from in-situ load tests carried out on drilled displacement piles sunk in a porous, lateritic and unsaturated soil deposit, are analyzed in this paper. Three slow-maintained load tests were performed on deep instrumented piles with a diameter of 0.37 m and around 12 m long. The soil deposit consists of a superficial, silty clay “porous” layer 6 m thick, with an average standard penetration blow count (NSPT) of 4 and cone tip resistance and sleeve friction (qc and fs) of 1.5 MPa and 48 kPa, respectively. Under this layer there is a residual stratum 10 m thick, geotechnically consisting of a “porous” clayey silt with an average NSPT of 7 and qc and fs of 2.4 MPa and 202 kPa, respectively. The water table was reached at a depth of 17 m below ground level. The results of the field load tests yielded a maximum pile load (average for the tests) of 1428 kN, which is twice as high as corresponding experimental values from standard bored piles with similar geometric conditions. Exhumation of one of the tested piles was carried out after the test, in order to check integrity and shaft conditions. Numerical finite element analyses, using the commercially available French Code LCPC Cesar®, were performed in order to back-analyze the geotechnical soil parameters for a post execution pile condition. The results permitted a better understanding of the improvement of the subsoil given the intrinsic execution characteristics of this particular pile. It was also possible to note that drilled displacement piles have great potential to become an economically viable solution in tropical soils, given the enhanced behavior of such piles when compared to alternative (cheaper) techniques. In fact, it has several advantages which should make it a key foundation type in the Brazilian market in the future.IntroductionMost buildings in tropical soils use, as the main type of foundation, deep bored or auger type piles. These types of foundations can be performed in various ways, for example with or without soil extraction, with or without bentonite mud and so on. Two main processes maybe formulated: the first execution process is typified by bored pile types, continuous flight auger piles etc., which do not cause excessive soil displacement during excavation. With respect to the second process, one could mention, amongst others, driven piles (precast concrete or steel), Franki piles and drilled displacement piles, which do displace the soil during excavation by pushing the soil laterally around the hole in order to allow either the penetration of the pile or the excavator auger."

Jan 1, 2014

By M. Abdellatif

Keywords: Magnesium, pyrometallurgy, Mintek Extensive testwork on atmospheric thermal magnesium production has highlighted certain important fundamental and operational factors that have a major influence on magnesium extraction and its extraction rate, the condensation efficiency of magnesium, as well as on the quality of the condensed metal. The possible impact of these factors on the selection and preparation of raw materials, recipe choice, furnace electrical energy consumption, and on the refining requirements of the crude magnesium is discussed. Selected pilot plant operational and metallurgical data are also presented.

Jan 1, 2006

As it is my opinion that deep alluvial mining in Victoria and in the Murray Flats in New South Wales is practically in its infancy, and considering that we, the old school of alluvial miners, who have thirty or forty years' experience to guide us, must in the natural order of things hand over the management of our mine, to the younger and less experienced' generation of miners, I thought that as our Association has been formed for the purpose of disseminating information and the exchange of ideas, a few notes on the practical working of alluvial mines might be of some service to aspirants for the position of mining manager.The greatest difficulty the alluvial miner has to contend against is the immense quantity of water contained in the drifts overlying the wash in the gutters or ancient river beds, and to cope with this water successfully and economically is the point to be aimed at by our mining managers; and if they thoroughly understand this part of their business in all its details, they will not only win kudos for themselves, but will be the means of saving large sums of money to the companies they represent, and, in many instances, will make a success of a venture which otherwise might be stopped for want of funds before it is properly proved. At the present time, although we have had over forty years' experience indraining the deep leads of the colony, I regret to say that a large amount of ignorance still prevails amongst both directors and managers.

Jan 1, 1901

By H. Antrekowitsch

Nowadays, the pyrometallurgical treatment in copper smelters is the common process for the recycling of metals from the electronic scrap. Furthermore the European Directive on the Waste from Electrical and Electronic Equipment (WEEE) and the Directive on the Restriction of Hazardous Substances (RoHS), increase the importance of electronic scrap recycling. Besides these a high amount of plastic and inert components in these materials leads to problems at the processing. An optimisation concerning the internal recovery and the high amount of plastic is necessary to reach the recycling quota of the European directive. The majority of the scrap is treated mechanically in order to separate in a first step plastics from metals, iron from nonferrous metals and harmful substances from valuable materials. But the quality of the different fraction often rather low and further treatment leads to higher costs. Therefore an interaction between mechanical treatment and metallurgical processing should be realised. The Christian Doppler Laboratory for Secondary Metallurgy of Nonferrous Metals at the Institute of Nonferrous Metallurgy at the University of Leoben carried out investigations concerning the optimisation of the metallurgical recycling and the treatment of the input materials especially of printed circuit boards.

Jan 1, 2006

The beach sand industry is the only Australian mineral industry which, so far, has used electrostatic separation on a full commercial scale. The main application of the process is for the separation of rutile from zircon. Laboratory work has demonstrated that electrostatic methods are effective for ilmenite-monazite and cassiterite-zircon separations, thus facilitating the production of high grade monazite and cassiterite products from top-strip table concentrates, but the commercial application of these processeshas been rather limited so far. Overseas, electrostatic methods are becoming more widely used for the treatment of granular material which is not amenable to flotation. The use of electrostatic separation for the treatment of ores other than beach sands has been investigated in this laboratory 1, 2, 3, and two pilot separators were built during i953 to carry out field tests. Of these, the first was an inclined feed plate separator for the removal of silica from granular lime-sand in Western Australia, the second a conductance roll separator for the removal of diamonds from alluvial gravel in New South Wales. In both cases the whole of the ore passed through the separator, not a gravity concentrate only as in beach sand practice. The two types of separator mentioned are shown diagramatically in Figs. 1 and 2.

Jan 1, 1954

By Lucien Eaton

THE use of filling in mines is less common in the United States than it is in Europe, where in some places it is required by law. In most cases the filling is placed by hand, and the material used for this purpose is the waste from development and that sorted from the ore in the stopes. When these sources provide an insufficient supply, additional rock must be quarried on surface or mined underground, or some other material :st be used. In different parts of the world sand, clay, gravel, culm, nulated slag, mill tailings, and even ashes, have been used as filling material in place of or in conjunction with rock. Of all the materials used for filling the best is probably clean sand. Gravel, finely crushed rock, granulated slag and coarse mill tailings are almost as good, and the methods used for placing and confining sand will apply equally well to any of these. The advantages of sand are its comparatively slight compressibility and the ease, economy and convenience with which it may be placed. On account of the voids, which necessarily occur in fills made of coarse waste, such fills will compress 10 to 25 per cent before they develop their full strength, whereas clean sand seldom compresses more than 5 per cent. Sand is especially desirable when practically complete filling is required, and sand derived from mill tailings, especially when not thoroughly cleaned, has been remarkably effective in sealing off and extinguishing mine fires. When natural sand is available on surface, or when it can be obtained from the mill tailings or tailings dump, the cost of using this material for fill will probably be considerably less than that of rock. In this paper it is not proposed to discuss all methods of filling, butt to describe some of the methods used for placing sand fill and to make a brief comparison of their merits.

Jan 1, 1932

As the question of zino recovery from lead blast furnace slags has lately become such an important subject with lead metallurgists, the following description of some of the work carried out in this oonnection by the Sulphide Corporation, at CockleCreek, should prove of interest to those concerned. Early in the life of the works it was realised by the metallurgical staff that a very wide field for investigation lay before them. At the head of these was the late Mr. F. H. Evans, and it was due to his work and suggestions that the question has grown from a mere hypothesis to a commercial undertaking, in so far as these works are concerned. A great deal of the early work was carried out in the form of small laboratory expe!iments, those giving the best results being ear-marked for subsequent trial on a larger scale. One of the main obstacles in the way of research was the lack of any data or information of similar work done in other...

Jan 1, 1920

By Gianni Bartolacci, Patrice Nadeau, Szatvanyi. Gerard, Carl Duchesne, Claude Chrétien

"Combustion is used throughout the mineral processing industry to produce steam in boilers, to dry concentrates in rotary dryers, and to apply heat treatments in pyrometallurgical furnaces. Tight combustion control is very important in latter type of furnace since the combustion conditions directly affect final ore quality. However, achieving tight combustion control is not straightforward since most of the flames encountered in industry are turbulent non-premixed flames, they are affected by several unmeasured disturbances and are often produced by burning several types of fuel simultaneously, some of them coming from other parts of the plant. A novel method is proposed in this paper to improve process and product quality control as well as to optimize the combustion conditions based on digital flame color images. Multivariate Image Analysis and Regression is to used extract the flame color characteristics from images to predict the solids discharge temperature of an industrial rotary kiln. It is shown that this method yield extremely good 10 minutes ahead forecast of the temperature and should lead to a substantial reduction in product quality variability as well as in fuel consumption.INTRODUCTIONFuel-fired furnaces are often used in the mineral processing industry for various purposes, such as for the production of steam (utility boiler), in conjunction with rotary dryers to dry mineral concentrates or in pyrometallurgical processes for induration, roasting, and so forth. These furnaces are necessary in the supply chain from the mine to the metals, but their operating costs are constantly rising due to the fluctuations in fuel prices. Moreover, these processes are now targeted by the Kyoto Protocol since they are energy intensive and they produce significant amounts of CO2 and other pollutants such CO, NOx and SO2. To achieve both a reduction in operating costs (i.e. fuel consumption) and in pollutant emissions while maintaining or improving product quality, one needs to have a very good control of the combustion process."

Jan 1, 2005

By Frank Rausche

Without doubt, driven piles are the most economical deep foundation element for a nearshore environment, providing for high bearing capacities and stiffness, quick installation times, assured quality by simple monitoring and inexpensive dynamic load testing during restrike testing. However, when the pile top elevation is several meters below water surface, questions often arise as to the most reliable and economical pile installation method. Frequently encountered, yet relatively expensive, solutions include driving inside a dewatered cofferdam, driving long piles that are later cut off below water surface, or using an underwater hammer. Arguably, the most economical solution is driving the piles with a follower or chaser. However, many foundation engineers shy away from this solution because of the uncertainty associated with the transfer of energy through the interface between follower and pile, the associated potential driveability problems and maybe the limited fatigue life of the follower. This paper will demonstrate how the driveability of a hammer-follower-pile-soil system should be analyzed prior to installation and how to model the pile-follower interface both for steel and concrete piles. As an example, results will be presented which were obtained for both steel pipe piles and precast concrete piles, driven by a single-acting diesel hammer through a steel follower for a pre-construction test pile program in Venice, Italy. While analysis of the steel pile-follower system was straightforward, for the concrete piles, the presence of a soft cushion material whose material properties changed continuously posed some difficulty. Pile Driving Analyzer® measurements and CAPWAP® analysis yielded not only realistic stresses and transferred energy values in the pile, but also reasonable model parameters for further use in a pure wave equation analysis. As a side note for clarity, the dynamic measurements and analysis results herein presented are based on the GRLWEAP and CAPWAP software. GRLWEAP is commonly used all around the world for the preparation of pile driving jobs. The program either yields a bearing graph that relates bearing capacity and pile stresses to blow count or set per blow or it predicts blow counts and pile stresses as a function of pile penetration. These results allow the contractor to estimate driving time and select an economical hammer and driving system for a safe and efficient installation. CAPWAP on the other hand is the analysis of choice once a pile has been installed and records of pile top force and velocity have been acquired during installation or during a restrike test. CAPWAP is a signal matching program which calculates for one particular impact (for example at the end of driving) the static and dynamic soil parameters. Its final results include the calculated resistance distribution, the complete stress history in the pile and also a simulated load set curve. The CAPWAP calculated dynamic soil parameters can also be used in a Refined GRLWEAP analysis to generate a calibrated bearing graph."

Jan 1, 2006

By J. E. Conley

Available statistics show that the demands of the American chemical industry for sodium sulphate have been increasing slightly in recent years. The supply from domestic sources, particularly In the form of byproduct salt cake from the acid manufacturers, has been tending to decrease due to the growing manufacture of synthetic acid. Both hydrochloric and nitric acids are being synthesized from their elements. The natural result has been that a smaller amount of salt cake is available. Simultaneously, the expansion of the Kraft paper industry, especially in the South, has brought about greater demand for sodium sulphate in that section. This dean is being met by domestic byproduct salt cake, by imported German sodium sulphate made from potash waste liquors, and by favorable situated domestic deposits of Glauber salts and tile anhydrous salt, thenardite. No shortage of natural sodium sulphate exists in the United States, but usually such deposits occur in semiarid regions far removed from transportation facilities and from markets. Moreover, the major portion of the natural deposits is Glauber salt or mirabilite (Na2SO4 ? 10H20), which must be dried or dehydrated in order to meet consumer requirements. The water of hydration represents, roughly, 55 percent of tae total weight of the crude salts and therefore has a very important influence on transportation costs. In marry instances the cost of getting, even the dehydrated product to market is the deciding economic factor. Therefore, the recovery oil production of anhydrous sodium sulphate from plant-.waste liquors or from natural brines of suitable composition might be economically feasible. The U.S. Bureau of Mines, at its nonmetallic Minerals Experiment Station, New Brunswick, N. J., has, for a number of rears, been investigating the commercial possibilities of treating the complex saline mineral polyhalite (K2SO4?NgSO4?2CaSO4?2H20) for the recovery of potash and magnesia. Certain proposed processes (1, 2, 3, 4)4/ yield waste liquors that contain the bulk of the magnesium and sulphate originally combined as magnesium sulphate in the polyhalite molecule. Sodium chloride In limited concentrations is also present, as extensive beds of salt occur in strata overlying the polyhalite deposits. A typical waste liquor would contain:

Jan 1, 1936