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By Gang Chen

Conventional methods designate a factor of safety, a deterministic number, to indicate the stability of a mine excavation. However, this deterministic description of excavation stability is frequently insufficient or inaccurate and, sometimes, misleading. Employing the probabilistic analysis to determine the likelihood of mine excavation failures will lead to a better understanding of ground control problems and result in more rigorous designs of the excavations. Based on the theory of probability, two approaches are taken in this study for the probabilistic analysis of excavation stability. The first one utilizes direct integrations for the estimation of failure probabilities of mine excavations. Due to the complexity of the integration, this approach can only be applied to solve relatively simple problems. In order to overcome the limitation of the direct integration method, the second approach employs the first-order second-moment approximation of the failure probabilities for more complex ground control problems. The probabilistic analysis offers a deeper insight into the uncertainty associated with the stability of mine excavations. The study indicates that the distributions of parameter values play a significant role in the mine excavation stability, which can not be disclosed by the conventional methods of stability analysis. Greater dispersiveness of the parameter values will lead to a different probability of failure, although the factor of safety estimated by conventional methods stays the same if the mean values of the parameters are constant. By taking consideration of the probabilistic distributions of the parameters, the probability model can provide more reliable designs of mine excavations.

Jan 1, 1996

By J. G. Henning, R. Edrissi

This paper describes a practical methodology, based on numerical modeling, for the prediction of progressive failure of underground-mine stopes having cable-bolt support. A case study of the 40-761 scope at the Kidd Creek mine, Timmins, Ontario, Canada is presented. Scope 40-761 was mined by blast hole open sloping in 1986 and was a lead scope within a mining block located between levels 36-1 and 38-2. Initially designed to peak at level 38-2, the scope back caved upwards =40 m towards level 36-1. After caving began, cable bolts were installed above the stope from level 36-1. The stope eventually stopped caving when the falling rock mass encountered a sufficiently high cable density. This paper provides details of the geomechanical data and modeling results of the case study. Numerical modeling of cable bolts around the mine stoke was carried out using a finite-element modeling software. The software, known as e-z tools, was developed by the first author.

Jan 1, 1996

By Mason P, Waller C

The Phase I electrowinning system at KCGM's Fimiston Operation utilised the well proven technology of electrowinning precious metal values onto steel wool followed by calcining and direct smelting to bullion. The above process, while reliable and successful, was to some extent labour intensive. The Williams Mine in Ontario, Canada had published conditions under which precious metal values are electrowon onto woven stainless steel and directly removed using high pressure sprays. The current paper describes the testwork which was carried out to check the applicability of the Williams criteria to KCGM eluates arising from the elution of highly loaded carbon from the calcine circuit and lowly loaded carbon from the float tails circuit. Information is also given on the commissioning and operational experience which occurred.

Jan 1, 1996

By Lawson F

Arsenic-containing waste was dissolved into molten slags and the leaching behaviour of the quenched arsenic-doped slags (containing up to 2.3 wt per cent arsenic) was ascertained to evaluate the potential of this method as a means for arsenic disposal. The leaching behaviour was evaluated using acetic and sulphuric/nitric acid based solutions.From short-term (18 hour) leach tests, the amounts of arsenic in the leach solutions were found generally to decrease with an increase in the Fe(III)/Fe(total) ratio of the slag or an increase in pH of the leach solution. The amount of arsenic in solution increased with an increase in the slag basicity, the slag arsenic concentration or the surface area of the slag exposed to the leach solution. From longer term leach tests (up to 40 weeks) in the pH range 5 to 8, the arsenic remaining in the leach solution was believed to be controlled by sorption processes. The sorbent was an iron oxide-rich material which had the capacity to lower the arsenic concentration in the leach bottles to well below 1 ppm in some cases. At a leach solution pH over 9, the arsenic concentration in the solution increased with time, although the rate of solubilisation was much slower due to the high pH.Slags have the potential to stabilise arsenic and prevent it entering the environment provided attention is paid to the slag chemical composition and oxygen potential.

Jan 1, 1996

By Cornell J. B

Scaling in Bayer Refineries is a natural consequence of the super-saturated liquors used in the process. The caustic liquor is supersaturated not only with alumina but also silica and calcia at various stages of the process. The basic scaling mechanisms are reviewed and examples of the two basic types, growth and settled scales, are given. Examples include gibbsite scales formed in the precipitators and silica scales formed in heat exchangers. The main factors affecting the rate of growth of growth scales are temperature and supersaturation and are highlighted using a silica scale example. For growth scales chemical cleaning rates can readily be predicted from kinetics and an example for a gibbsite scale is given. For settled scales the growth rate cannot be predicted and the hydrodynamics within the system have most effect. There is no simple method to predict the potential for chemical cleaning of settled scales; some of the relevant issues are discussed, in particular methods to identify the cementing phase in the scale. An example of design considerations for a scaling system, transport of slaked lime, is Given.

Jan 1, 1996

By D. Limpitlaw

As coal mining often results in the generation of acid mine drainage (AMD), careful planning and management of the water on such mines is required. A colliery in Mpumalanga recently sponsored independent research into the pollution-ameliorating potential of a natural wetland that has been receiving AMD for at least two decades. Samples of the sediment collected in the wetland were subjected to nine stages of sequential extraction in a determination of the distribution of the metal species present. The samples were then analysed for aluminium, iron, and manganese. The concentrations of sulphate-reducing bacteria (SRB) were also determined. The SRB concentration was found to increase with distance downstream (away from the source of pollution). An analysis of the sediment speciation data indicated that metal immobilization may be optimal in areas where the organic adsorption of metals is at its greatest. The analysis also provided evidence of the biogeochemical improvement of the water quality as the AMD passed through the wetland environment. The metal species present did not correlate strongly with the SRB populations; nor did the soluble species correlate with the species formed over long periods of time.

Jan 1, 1996

By S. G. Kumar, R. G. Reddy

"Niobium aluminides offer the advantage of higher high temperature capability compared to other intermetallic aluminides due to the refractory nature of niobium. However, the reaction sequence in Nb-Al system is sluggish and currently there is a great interest in the processing aspects of these materials. In the present study, a systematic investigation was undertaken to compare the effect of different powder metallurgy processing routes on the phase relations and microstructure of 66Nb-22AH2Ti (in atom percent) alloy. The three different process routes adopted were: (i) cold pressing followed by reaction sintering; (ii) cold pressing and hot pressing followed by sintering; and (iii) arc melting, hydride-dehydride process to make the alloy powder followed by cold pressing and then sintering. The samples are analyzed by XRD, Optical Microscopy, SEM-EDS and EPMA. The analysis showed that alloy pellets made from pre-alloyed powders i.e., arc melting followed by hydride-dehydride process, gave good densification and more Nb3Al formation.1. IntroductionTo improve the performance standards of turbine engines, materials scientists are challenged to develop materials that have· high thrust-to-weight ratio with high specific strength, high specific modulus and good environmental properties at elevated temperatures. The conventional high temperature materials like nickel based superalloys are high in density and hence many of the high temperature materials scientists have focussed their attention on intermetallic aluminides like Fe-AI, Nb-AI, Ni-AI and Ti-AI in recent years. The phase relations and properties of alloys based on Fe-AI, Ni-AI and Ti-AI are fairly well known whereas little is known about the alloys based on niobium aluminides."

Jan 1, 1996

By P. Hornby, S. Henley

INTRODUCTION The project described in this paper is designed to provide a standard and flexible method by which data can be exchanged among different systems and packages in common use for geo- logical modelling and mine planning, with substantial savings in ad hoc programming which is expensive and produces interface software that is difficult to maintain. Such packages include specialised applications such as Vulcan, Surpac, Datamine, and Gemcom software, and the Whittle pit optimisation programs, and more general products such as AutoCad, Microstation, and Maplnfo, and database management systems through a generic SQL interface. The data translator is built around the CSIRO Data Model and GeoEditor, and will make widely available the benefits of the Data Model by adding functionality to its implementation in an industry- standard language and style, with interfaces to important geological and mining software products used by the industry, while including also the visualisation and editing capabilities of the GeoEditor which provides the functional framework within which the Data Translator is developed. The Data Translator is intelligent in the sense that it is not a black-box solution but allows visualisation and validation of data during transfer; furthermore it provides a means for changing abstraction levels during the transfer operation. There have been few similar efforts to address this problem. It is not a problem which is likely to be solved in any general or long- term way by any individual commercial software vendor. THE CSIRO DATA MODEL A wide variety of software tools have entered the exploration and mining industries via different pathways. Examination of these pathways and the origins of the software illuminates the types of data transfer problems and difficulties which might occur in the day to day life of exploration and mining operations. In exploration, the focus is normally on a large area (>5000km2) which is explored primarily in two dimensions. For 20 exploration purposes, geographical information systems (GIs) software, image processing software, and, in some cases, 20 computer aided design (CAD) software have been employed. Typically, GIs soft- ware is used the most by lands and tenements personnel and government geological survey organisations, image processing software is used the most by geophysicists, and 20 CAD software is used the most by drafting and geology personnel. In contrast, within the mining environment, almost all activities have 3D character. In this realm, 3D CAD software and specialised mine planning and design software are important. Specialised mine planning and design software is similar to 30 CAD software, but typically has additional capabilities such as specialised modules for surveying, drill hole data operations, open pit design and optimisation, underground mine design, mining block model creation, and/or ore reserve calculations. Unfortunately, the different origins of the software in exploration and mining lead directly to problems in data exchange and the design of seamless software systems. These problems result from the different data management strategies employed by the different classes of software. In order to address these problems, CSIRO Exploration and Mining and CSIRO Division of Information Technology have been investigating the structure, character, and syntax of data and soft- ware present in computer-aided exploration and mining activities since early 1993. The goal of this effort is to 1) systematically ex- amine the breadth and depth of the data in use within exploration and mining, and to 2) promote a data organisation strategy which is broad enough and comprehensive enough to enable wiser soft- ware design and easier data transfer. In the short term a data model can be used to improve data transfer; in the longer term it is hoped that a data model framework will help object-oriented concepts to enter the next generation of geoscientific software. The data model is described in more detail by Power et al., 1995. THE DATA TRANSLATOR PROJECT The CSIRO Data Model provides a basis for a very wide range of applications in geology and mining. It has been developed over the past two years by a joint team from the Division of Exploration and Mining and the Division of Information Technology, and its principal purpose is to provide a comprehensive and self consistent model of the geometric and topological properties of geological and mining data. The project is being carried out by CSIRO with the support of Australian mining companies through AMIRA (the Australian Mining Industries Research Association). Eight companies are sup- porting the project : • North Ltd Minenco • MIM Exploration • Fractal Graphics • BHP Australia Coal • Pacific Coal • Gencor CRA Exploration The systems to be interfaced have been decided by comparing the priorities of the various sponsors, to produce a final combined priority list as follows : • Vulcan • Minescape • Micromine • Mapinfo INTRODUCTION The project described in this paper is designed to provide a standard and flexible method by which data can be exchanged among different systems and packages in common use for geo- logical modelling and mine planning, with substantial savings in ad hoc programming which is expensive and produces interface software that is difficult to maintain. Such packages include specialised applications such as Vulcan, Surpac, Datamine, and Gemcom software, and the Whittle pit optimisation programs, and more general products such as AutoCad, Microstation, and Maplnfo, and database management systems through a generic SQL interface. The data translator is built around the CSIRO Data Model and GeoEditor, and will make widely available the benefits of the Data Model by adding functionality to its implementation in an industry- standard language and style, with interfaces to important geological and mining software products used by the industry, while including also the visualisation and editing capabilities of the GeoEditor which provides the functional framework within which the Data Translator is developed. The Data Translator is intelligent in the sense that it is not a black-box solution but allows visualisation and validation of data during transfer; furthermore it provides a means for changing abstraction levels during the transfer operation. There have been few similar efforts to address this problem. It is not a problem which is likely to be solved in any general or long- term way by any individual commercial software vendor. THE CSIRO DATA MODEL A wide variety of software tools have entered the exploration and mining industries via different pathways. Examination of these pathways and the origins of the software illuminates the types of data transfer problems and difficulties which might occur in the day to day life of exploration and mining operations. In exploration, the focus is normally on a large area (>5000km2) which is explored primarily in two dimensions. For 20 exploration purposes, geographical information systems (GIs) software, image processing software, and, in some cases, 20 computer aided design (CAD) software have been employed. Typically, GIs soft- ware is used the most by lands and tenements personnel and government geological survey organisations, image processing software is used the most by geophysicists, and 20 CAD software is used the most by drafting and geology personnel. In contrast, within the mining environment, almost all activities have 3D character. In this realm, 3D CAD software and specialised mine planning and design software are important. Specialised mine planning and design software is similar to 30 CAD software, but typically has additional capabilities such as specialised modules for surveying, drill hole data operations, open pit design and optimisation, underground mine design, mining block model creation, and/or ore reserve calculations. Unfortunately, the different origins of the software in exploration and mining lead directly to problems in data exchange and the design of seamless software systems. These problems result from the different data management strategies employed by the different classes of software. In order to address these problems, CSIRO Exploration and Mining and CSIRO Division of Information Technology have been investigating the structure, character, and syntax of data and soft- ware present in computer-aided exploration and mining activities since early 1993. The goal of this effort is to 1) systematically ex- amine the breadth and depth of the data in use within exploration and mining, and to 2) promote a data organisation strategy which is broad enough and comprehensive enough to enable wiser soft- ware design and easier data transfer. In the short term a data model can be used to improve data transfer; in the longer term it is hoped that a data model framework will help object-oriented concepts to enter the next generation of geoscientific software. The data model is described in more detail by Power et al., 1995. THE DATA TRANSLATOR PROJECT The CSIRO Data Model provides a basis for a very wide range of applications in geology and mining. It has been developed over the past two years by a joint team from the Division of Exploration and Mining and the Division of Information Technology, and its principal purpose is to provide a comprehensive and self consistent model of the geometric and topological properties of geological and mining data. The project is being carried out by CSIRO with the support of Australian mining companies through AMIRA (the Australian Mining Industries Research Association). Eight companies are sup- porting the project : • North Ltd Minenco • MIM Exploration • Fractal Graphics • BHP Australia Coal • Pacific Coal • Gencor CRA Exploration The systems to be interfaced have been decided by comparing the priorities of the various sponsors, to produce a final combined priority list as follows : • Vulcan • Minescape • Micromine • Mapinfo • Medsystem

Jan 1, 1996

By M. Fofana

The use of a laboratory-scale magnetic fluid-based separator for coal separations was examined. A Frantz laboratory magnetic separator was modified by fabricating new pole pieces of the appropriate geometry to provide the proper magnetic field gradients. Two separation chambers, which were constructed out of Plexiglas, were designed to fit between the pole pieces. A commercially available, water-based, ferro-magnetic fluid was used as the separating medium. The separating density was changed by varying the intensity of the electromagnet. Both batch and continuous separations were made using 0.59x0.50 and 0.18x0.15 mm coal. The results are compared to those obtained using organic liquids.

Jan 1, 1996

By M. Niec

Poland lies at the junction of three geologic provinces: the East European Precambrian platform, the Middle European Paleozoic platform, and the Alpine orogenic belt comprising the Carpathian Mountains. However most of the rocks that contain mineral deposits and many of the recently explored and mined deposits are commonly hidden under thick overburden, sometimes up to over 500 m thick. The discovery of these mineral deposits was due to the combination of geologists talents for inference and the keen interpretation of geophysical data ultimately tested by drilling. Examples of such use of the state-of-the-art geology include the following: 1. Sedimentologic and paleogeographic reconstructions led to the discovery of 8.8 Gt of bituminous coal under 500 m of Jurassic and Cretaceous cover in the Lublin basin, 2. Tectonic and paleogeografic data suggested a potential for discovery of burried Upper Permian copper de-posits on the Foresudetic monocline; subsequent exploration discovered 75 Mt of copper and 0,17 Mt of silver, 3. Geological interpretation of gravity and magnetic da-ta combined with sedimentologic data and regional subsur-face geology resulted in the location of 1.3 Gt of Fe-Ti-V ore in the Precambrian basement of northeastern Poland under -500 m of cover 4. A combination of metallogenic theory and geological interpretation of regional geophysical mapping led to the discovery of Caledonian-Hercynian granites and grano-diorites with accompanying porphyry-type Mo-W-Cu ores below 300 m cover on the northeastern border of the Upper Silesian coal basin 5. Tectonic reconstructions based on gravity and seismic data combined with theory on the origin of native sulfur led to the discovery of 1.0 Gt of native sulfur under cover up to 300 m thick. Five deposits were found at the northern margin of the Carpathian Foredeep. The other deposits found include lignite, polyhalite, lead-zinc ores.

Jan 1, 1996

No paper available.

Jan 1, 1996

By V. Bondarenko

The forecasting of floating earth inrush into the working is to a great extent connected with the investigation of the rock mass stressed-deformed state around the working. The aim of such investigations is to estimate the carrier ability of the protective layer (which is stabilized by the physico-chemical mode of fixing) and to determine it's thickness, which is to be sufficient to present the floating earth inrush into the working. We consider the protective layer to have exhausted it's carrier ability if the rocks of this layer reached the overlimit phase of deformation and it's greater part (section), which adjoins the working. is destroyed up to the limit of the remaining strength. So, the aim of investigations is to determine the size of the rocks inelastic deformation zone in the roof of the working. It is necessary to take into account the presence of water saturated seam in the roof and the overlimit characteristics of the rocks, their ability to lower the carrier capacity up to the level of the remaining strength.

Jan 1, 1996

By H. S. Chang

A three-dimension two-phase (air and dust) computer model was developed to model air velocity and respirable dust distributions in the longwall faces. This paper describes the derivation of the model including the model features, mathematical equations and boundary conditions. Example simulations were also performed for two longwall faces where measured respirable dust and air velocity distributions were available. The results indicated the model can simulate the mine conditions fairly accurately.

Jan 1, 1996

By Y. J. Wang

In the mathematical analysis of electrical networks, the electrical devices are often modeled using idealized network elements such as current sources, voltage sources, and resistors. An analogous approach is outlined here for the modeling of mine ventilation networks, which can be considered nonlinear resistive networks. The modeling technique proposed uses five basic (non-reducible) elements: the H element, the Q element, the D element, the R element, and the N element. These elements are characterized by their (a) pressure gain or loss, (b) air quantity, and (c) pressure-versus-quantity relationship, each of which may be known or unknown. In addition to the definition of the basic elements, the necessary conditions for which there exists a unique solution are discussed. This is performed using theoretical developments derived from electrical circuit theory and illustrated in example networks. The proposed procedures are useful in the solution and characterization of mine ventilation networks.

Jan 1, 1996

By G. de Alva

"Industrias Peñoles S.A. de C.V. (Peñoles) is a private enterprise and is the main silver producer in Mexico. Peñoles is a Mexican Company, and since 1887 ranks as one of Mexico's main natural resources industrial groups.Peñoles Mining Group includes six operating Companies producing mainly gold, silver, lead, and zinc. All mines are underground operations, and the ore is milled in ten concentrator plants near the mine sites. Plant throughputs range from 150,000 to 810,000 tonnes per year.This paper gives a general view of the Peñoles Mining Group, their type of deposits, mining methods, and mineral processing work practices.The paper also discusses some of Peñoles work philosophies and measures being adopted to become more competitive. Due to the small size of the deposits, the mining methods used and size of the concentrator plants are somehow different to those typically seen in large deposits. This could make the paper more interesting.IntroductionIndustrias Peñoles S.A. de C.V. (Peñoles) since 1887 ranks as one of Mexico's main natural resources industrial groups; initially in the mining field and afterwards in the metallurgical, chemicals and refractories areas.Peñoles is integrated as follows: a Mining Group; an Exploration, Engineering and Construction Groups; the Metals Group; and the Chemicals Group.Peñoles is a Mexican Corporation devoted to the location, extraction, industrialization and commercialization of natural resources under its control, performed in an efficient and responsible manner for the benefit of its shareholders, employees and the communities where it operates, through blending and managing a portfolio of sound highly profitable business, offering products and services with integral quality; leaders in their respective fields or with an outstanding presence; technologically and operatively effective, with ecological consciousness and international projection, and an image of prestigious integrity."

Jan 1, 1996

By Stewart B. Nelson

With the pending U.S. ratification of the United Nations Convention on the Law of the Sea (UNCLOS), the subject was raised as to the Convention's potential impact on U.S. ocean science. The Ocean Studies Board (National Academy of Sciences) elected to convene a two-day workshop in October 1995 to consider the potential impacts and to determine whether or not they warranted a more formal and intensive study. A review of the workshop discussions and deliberations concerning the matter of UNCLOS and U.S. ocean science will be presented.

Jan 1, 1996

By Roger Amato

The 1982 United Nations Convention on the Low of the Sea includes provisions under Article 76 for extending a coastal State's jurisdiction beyond the 200-nautical-mile (nm) Exclusive Economic Zone (EEZ) and for establishing the seaward limits of sovereign rights over natural resources. Article 76 prescribes a set of methodologies for determining these outer limits based on physiography and sediment thickness. The methodologies were applied to each of the five continental* margin areas of the United States - Atlantic, Pacific, Gulf of Mexico, Alaska, and Pacific Islands-using existing digital hydrographic and geologic data. Figures 1 and 2 show the results of applying the methodologies to the Atlantic, Pacific, Alaskan, and Gulf of Mexico continental shelves. Figure 1 depicts the preliminary limits of each of the Article 76 determinations for the Atlantic and Gulf of Mexico continental shelves. The Atlantic limits were described by Carpenter, Thormahlen, and Amato (1995) at the 26th Underwater Mining Institute.1 The limits for the Alaskan continental shelves are shown in Figure 2. Additional areas beyond the 200 nm EEZ are highlighted. These include a small area north of the U.S. - Canada boundary, containing 7,000 km2, a large area north of Point barrow (395,000 km2), and a third area north of the Aleutian Islands (178,000 km2). The shelf between the first two areas appears to have sediments thick enough to qualify for the 1 percent method (Irish Formula); however, year-round ice cover has prevented acquisition of seismic or drill data. The entire northern Alaska shelf is prospective for petroleum The Gulf of Mexico (Figure 1) has two small areas beyond the EEZ known as "doughnut holes." One is south of Louisiana and includes part of the Sigsbee Escarpment, an area believed to have potential for oil and gas. Oil was found on Sigsbee Knoll in cores from Deep Sea Drilling Project's Leg 1 cruise in 1968. The Sigsbee areas contains about 6,000 km2. The second area is south of the Florida panhandle and contains about 12,000 km2.

Jan 1, 1996

By Paul F. Saxton

Introduction As the world economies continue to face an increased demand for natural resources to support growth in the established and developing world, the western mining industry has expanded its operations and funding of mineral developments into new and relatively unexplored regions of the world. Mining companies worldwide, in order to grow in a global economy, are now actively exploring and developing mineral resources in the emerging markets of South and Central America and most recently have expanded activities throughout Asia. South East Asia Resources (S.E.A. Resources) has recognized the vast resource potential offered by countries such as China, India and Indonesia, Asia's main driving forces of economic growth and has made a commitment to be actively involved in the area. These countries rich in mineral resources, represent some of the highly prospective and underexplored regions on earth. Their vast potential has been underestimated because of political reasons and overlooked as Central and South America still continue to be the focus of exploration for many mining companies. Most of these Asian countries have faced a prolonged period of political unrest and it has not been until recently that they have begun to enjoy a relatively stable political climate which has encouraged foreign investment, growth and economic development. These countries are in need of capital to develop their infrastructure and market economies. Their wealth in resources is one of the best methods to achieve their goals. Gold is usually one of the first targets to be extracted from developing economies. Equivalent-sized gold projects tend to cost less to develop and require less supporting infrastructure than base metals. These projects are easier to finance and, most important of all, tend to give a quicker return on investment than that offered by base metals. They also provide the economy with precious foreign exchange, international investment and the technology required to build the country. Following is a graph representing the global re-allocation of the total capital investment on the twenty largest gold projects now under construction with the total for those under construction in 1990.

Jan 1, 1996

By Daniel Levacher

Pile load tests in site require extensive means of action and time. To get outstanding tests, the environmental test conditions must be perfectly known and acceptable. They concern the support installation, the loading, the access and instrumentation site conditions and the economical aspects. In particular cases as offshore areas, the load tests are not feasible. Moreover the variability of soil characteristics limits the interpretation results at the considered tested site. The use of centrifuge modellling offers an other way to study the loaded pile behaviours. Centrifuge tests lead to parametric approaches which constitute for geotechnical engineers an important data base tor recommendations and design codes. To accurately simulate pile behaviours by checking similitude laws linked to the studied problems, the installation of model-piles must be also representative of the in-situ piles. Driven piles account for a large part of the piles installed through the world, mainly for offshore or harbour constructions. So, to explore driven pile problems by centrifuge tests, miniature pile driving hammers must be developed and tested under macro-gravities. The paper describes two types of these ones in details. They are commonly used at the centrifuge centre of the Laboratoire Central des Ponts et Chaussées - (LCPC) - [Réf. 1] for different deep foundations researches. Performances and limitations are given for both miniature pile drivers and some results from their use are presented to illustrate the suitability of these apparatus.

Jan 1, 1996

By J. D. Miller

Fluid flow phenomena and therefore the flotation efficiency of air-sparged hydrocyclone (ASH) flotation are strongly dependent on operating and design variables such as air and slurry flow rates, underflow and overflow opening areas, percent solids of the feed, reagent levels, particle size and ASH length. Time-averaged multiphase flow characteristics, as determined by X-ray CT (described in a previous publication), are used to understand and explain the steady-state ASH flotation of quartz. A detailed parametric study of quartz flotation by a nominal 2in. diam. air-sparged hydrocyclone (ASH-2C) revealed the influence of these variables on the flotation response, which is discussed in terms of the multiphase flow characteristics. Thus, a phenomenological description of quartz flotation has been established to assist in the further development and utilization of the ASH technology.

Jan 1, 1996