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By J. D. Steenkamp

In a paper presented at the Heavy Minerals Conference 2001 a laboratory scale investigation on the beneficiation of an ilmenite containing waste stream by magnetizing roasting was reported1.This waste stream contained a high concentration of ilmenite, which was contaminated by chromite and other gangue minerals. Interpretation of the results of the investigation was based on the assumption that during magnetizing roasting of an ilmenite concentrate, under the oxidizing conditions, the magnetic properties of the chromite would remain constant. In this article thefollowing hypothesis was tested: The magnetic susceptibility of chromite would remain constant during magnetizing roasting of an ilmenite concentrate under the oxidizing conditions reported by Gouws and Van Dyk1. The results of this study indicated that the hypothesis is not true. The increase in the magnetic susceptibility is not significant though and it is expected that it will not influence the final ilmenite quality to a large extent. Based on the assumptions that the bulk magnetic susceptibility of the waste stream samples represents that of the ilmenite in the waste stream, and the bulk magnetic susceptibility of UG1 chromite that of the of chromite in the waste stream, the results also served to confirm that the waste stream with a high chromite content should be roasted under oxidizing conditions, in a reactor with a well-defined retention time distribution (i.e. a fluidized bed reactor), at a roasting temperature of 750°C (rather than the higher temperature ranges of 800°C and 850°C).

Jan 1, 2003

By Siyabonga Malevu

Chemical Initiatives? Umbogintwini plant is the production facility of Chemical Initiatives? business. Umbogintwini?s J Plant manufactures sulphuric acid. The plant was designed and built by Simon Carves, and was commissioned in 1974. The plant was designed to produce 500 tons/day of Sulphuric acid (H2SO4) at maximum rates. The Sulphuric acid manufacturing is through the famous contact process whereby liquid Sulphur is injected through dried air in a burner operating at 1000 °C to form sulphur dioxide (10.5% SO2). The SO2 gas is then cooled in waste heat boiler no. 1 before being fed to a four pass converter which provides 99.5% SO2 conversion to sulphur trioxide (SO3). The SO3 gas is the absorbed by 98.5% H2SO4 through the inter-pass & final tower to make more concentrated acid and dilute it with water back to 98.5% H2SO4 in acid pump tanks and dispatched to storage tanks. The manufactured Sulphuric acid is supplied to a variety of industrial manufacturing customers includes Pulp & Paper industry, Mining industry, Chemical manufacturing industry etc.

Jan 1, 2009

By Siyabonga Malevu

Chemical Initiatives? Umbogintwini plant is the production facility of Chemical Initiatives? business. Umbogintwini?s J Plant manufactures sulphuric acid. The plant was designed and built by Simon Carves, and was commissioned in 1974. The plant was designed to produce 500 tons/day of Sulphuric acid (H2SO4) at maximum rates. The Sulphuric acid manufacturing is through the famous contact process whereby liquid Sulphur is injected through dried air in a burner operating at 1000 °C to form sulphur dioxide (10.5% SO2). The SO2 gas is then cooled in waste heat boiler no.1 before being fed to a four pass converter which provides 99.5% SO2 conversion to sulphur trioxide (SO3). The SO3 gas is the absorbed by 98.5% H2SO4 through the inter-pass & final tower to make more concentrated acid and dilute it with water back to 98.5% H2SO4 in acid pump tanks and dispatched to storage tanks. The manufactured Sulphuric acid is supplied to a variety of industrial manufacturing customers includes Pulp & Paper industry, Mining industry, Chemical manufacturing industry etc. During the 1st quarter of the year 2007, Chemical Initiatives undertook a study to up rate the sulphuric acid plant output by 10% (i.e. from 500 tpd to 550 tpd).

Jan 1, 2009

By D. He, A. Yaacoubi, A. Baçaoui, K. Boujounoui, A. Abidi, K. El Amari

The effects of utilizing recycled tailings pond water from the flotation plant at the Mining Company of Guemassa (MCG) on galena recovery and selectivity towards chalcopyrite (RPb-Cu) , sphalerite (RPb- Zn), and pyrrhotite (RPb-Fe) were studied at bench scale. The results showed that recycling the tailings pond water in the lead circuit without addition of fresh water gave a good flotation performance in terms of lead recovery (Rpb) (75%) and selectivity towards the other metals: RPb-Cu (54%), RPb-Zn (60%) and RPb-Fe(65%). This allows the water to be recycled at least four times. However, increasing the d80 from 100 μm to 160 μm currently used at the MCG plant had a negative effect on the lead flotation performance.

Nov 30, 2022

Mr D. Wilson was born in Vereeniging, where he also completed his schooling, matriculating from General Smuts High School in 1977. Mr K.A. van Gessel was born in 1937. His final studies were conducted at Delft University, where he graduated with an M.Sc. degree in mining engineering. Mr J.G. McCaUum was born in 1938 and matriculated at Jeppe Boys' High School, Johannesburg. Mr H. Scot RusseU started his mining career at Randfontein Estates Gold Mining Co. Witwatersrand, Limited, where he served as temporary Geological Assistant, Sampler, Surveyor, Shift Boss, and Mine Overseer. Mr A.M.P. Henderson was born in 1950, in Kiel, West Germany. Mr J.L. Nel matriculated in 1957. This was folowed by his atainment ofthe folowing degrees: B.Sc. (Chemistry, Physics) in 1961, B.Sc. Hons. (Metalurgy) in 1965, M.Sc. (Metalurgy) in 1967, and MDD (student of the year) in 1981

Jan 1, 1989

By G. L. Smith

As the Platinum mining industry expands in the Eastern Limb of the Bushveld Complex it is increasingly evident that a major constraint to development is a lack of appropriate infrastructure. Of critical concern are water resources and spatial development / infrastructure. This paper identifies the context for infrastructure development in the Eastern Limb and two solutions that have evolved in the areas of water supply and spatial development. INTRODUCTION In an economics context, infrastructure is considered to be the structural elements of an economy which allow for the production of goods and services, without themselves being part of the production process. Despite the lack of a specific definition, infrastructure has largely become understood as to comprise road and rail transport systems, public transport systems, airports, public educational facilities, water supply and water resources, wastewater management, solid waste treatment and disposal, electric power generation and transmission, telecommunications and hazardous waste management systems. Critically it is important to understand that infrastructure not only comprises these physical elements but also the operating procedures, management practices and developmental policies that facilitate the effective utilization and development of the infrastructure in response to societal demand.

Jan 1, 2008

By B. K. Loveday

The South African Institute of Mining and Metallurgy hosted a School on 'The Practical Design of Comminution Processes' at Megawatt Park (near Johannesburg) on 14th to 16th May, 1991 Derek Barratt, a Senior Consultant of Wright Engineers, Canada, and the main speaker, provided a good insight into how Wright Engineers design milling circuits, particularly large semi-autogenous mills. He was ably assisted by Jens Lichterof Allis Mineral Systems, who described some interesting examples of pilot-plant testwork and summarized South African milling practice. Mike Moys of the Witwatersrand University spoke on the influence of pulp viscosity on mill performance, and Johan Engelbrecht and Jeremy Bosman of Multotech

Jan 1, 1991

By P. He

Abstract This paper introduces tested results of rock-socketed pile in Nanjing, Wuhan and Chongqing. From a force- transfer model, a distribution of axial force for pile-body and inlaid resistance for rock-socketed pile was deduced. Comparing the results of test and calculation, it shows that the calculation result coincide with the test result. Keywords rock-socketed pile, load transfer, inlaid resistance, end resistance. Zusammenfassung: dieser text legt eine kuyze Einfuehyung ueber die Erfolge wissenschaftlicher Forschungsarbeit in bezug auf die Grundprinzipien der Mechanik von Belastungsuebermittlung der Einlegesteinpfeilers der Durch Benutzung von Ausgleich/Balance der inneren Kraft und Deformationskoordinierung wird das mechanische Modell der Belastungsuebermittlung des Einlegesteinpfeilers aufgestellt. Vom lebendigen Beispiel wird dia Wellenkraft des Steinpfeilera und die Verteilungskurve Einlegebfestigungskraft ausgelegt, man hat diess bereits mit der tatsaechlichen genessenen Kurve verglichen. Schluesselwoerter: Einlegesteinpfeilers, Belastungsuebermittlung, Einlegebfestigungskraft, Seitenwiderstand. Résumé - Le présent article décrit de façon succincte des résultats de la recherche sur le mécanisme du transfert de chargement du pieu d’ancrage au massif. Une modèle dynamique du transfert de chargement du pieu d’ancrage au massif est ainsi établie avec l’application des conditions de l’équilibre de contraintes internes et de coordination de la déformation. L’expérimentation sur des exemples réels a permis de mettre à jour des courbes de distribution de la force axiale du corps du pieu et de la force d’ancrage avec comparaison aux courbes effectivement mesurées in situ. Mots clés - Pieu d’ancrage au massif, Transfert de chargement, Force d’ancrage, Résistance à la pointe

Jan 1, 2003

By E. M. Bloomfield, C. A. Jermy

Geotechnical tests were carried out within an area of the coastal sand dune cordon of northern KwaZulu-Natal which is currently being exploited through mining of heavy mineral sands. In situ and laboratory tests were carried out to assess the density, strength and stability of the dune sand material before and after mining. The most stable combination of sand (>63µm) and fines(<63µm) material was determined as well as the effects of compaction on the strength and permeability of the sand dune samples. In situ DCP and density tests showed that the sand dunes fall in density immediately after mining has taken place. However, settlement of the dunes occurs with time and the density increases within the top 2 metres, and particularly once the dunes become re-vegetated. Laboratory tests carried out showed that the dune sand with between 20% and 30% added fines had the highest shear strength and dry density, but the permeability was shown to decrease steadily with increasing fines up to 40% fines added. The addition of fines would result in steadily increasing water flow problems. Compaction of the dune sands was shown to significantly increase the density and the shear strength, but with a corresponding dramatic decrease in the permeability of the material. Slope stability analysis carried out on models of the dunes with increasing fines showed that the addition of fines increases the stability of the dune sands up to a peak of about 30% fines added, and compaction further increases the stability of the dune sands. Despite the benefits of compaction on the stability of the tailings dunes, the loss of permeability is thought to outweigh the benefits as well as the high costs involved. The stability of the tailings dunes greatly increases after re-vegetation. Compaction and densification of the tailings dunes may be necessary within the top 2 m interval if large-scale construction takes place on the sand dunes. Petrographic analysis was performed to understand the granular interactions of the sand and fines fractions, and the effect of the in situ weathering of the dune sands on the stability of the sand dunes. As the fines contents increase the gaps between the sand grains are filled, until a point where the percentage of fines begins to push the sand grains apart.

Jan 1, 2003

By J. Galloway, P. K. Hofmeyr

Obviously all mining operations require much analytical work to be carried out. This starts with exploration, becomes more stringent with the evaluation of a mineralised area and finally becomes on-going when mining operations are under way. All these phases are carried out by geologists, metallurgists and mining engineers. They require analyses to carry out their functions but usually have no involvement in the analyses themselves. Analyses are carried out at commercial laboratories or in-house analytical laboratories. In the past in South Africa the tendency was for the larger mining houses to have their own centralised laboratories for exploration samples with each mine having it?s own laboratory to meet only that mine?s requirements. The centralised laboratory maintains QC functions at the subsidiary laboratories. In other mining areas of the world there has been a strong tendency for all geological analytical requirements, especially for exploration and mining, to be carried out at commercial analytical laboratories. In recent years there has been a tendency for mines in South Africa to move in the same direction. This paper discusses the factors that need to be taken into consideration when a new laboratory is being planned and automation is an option. The planning of the laboratory at the new Langer Heinrich Uranium mine in Namibia is discussed considering these factors. 2.0 REQUIREMENTS OF A MINING ANALYTICAL LABORATORY The purpose and requirements of a mining analytical laboratory are fairly obvious and can be summarised as follows :- 1. All mining operations must have access to analytical facilities, either in-house or commercial 2. The laboratory must be able to handle all the sample types submitted by the mining operation These can be mining, exploration and/or plant samples. They can comprise solids (rocks, bore-cores), slurries and/or liquids.

Jan 1, 2007

By I. E. Teymenson, L. A. Bakhvalov

Irrational usage of mineral commodities leads to depletion of natural resources and various ecological violations in natural environment. Fulfilment of a number of measures and strategic decisions by given problems requires a correct forecast of trends of social-economic systems. For solving the task of long-term forecasting special procedures, considering Kondratyev’s big cycles of world conjuncture, have been embedded into algorithms of unknown parameters identification and recovering of factors of different countries mineral resources production and consumption models. In the paper the classification of long cycles types, existing forecasting algorithms on the basis of Kondratyev’s ‘long waves’ or ‘K-waves’ and the modified algorithm, developed by us, which allows to reduce time and financial expenses and to improve the forecast quality, are presented. Furthermore, the article includes several forecasts of mining branch corrected models factors, received by us, permitting complex prognosis of economic and social development of different scale and control level systems. In the paper workability of proposed forecasting algorithms on the base of ‘K-waves’ and adequacy of created models to researched processes are proved.

Jan 1, 2003

By PC Pistorius, DR Groot

The South African base metals industry has been one mainly focused on the production of metals or metal compounds from primary ores. This is true for metals such as titanium, vanadium, chrome, manganese, cobalt, nickel, copper, zinc and aluminium. The steel making industry has traditionally used a substantial portion of scrap steel, and could thus be considered to be somewhat of an exception. Secondary sources have played much less of a role, possibly due to at least some of the following factors. Scrap material is often of unknown composition, and thus it requires additional chemical analysis, and possibly special treatment. Tonnages are relatively small, and the incorporation of secondary materials is possibly seen to carry undue risk and inadequate benefit. South African consumers are still not very conservation and recycling conscious, which limits the amount of scrap made available. This attitude might also be expected to influence decision makers in these industries. Finally, pressure from environmentally motivated activists locally has not been unduly large. This landscape has been changing, and is continuing to do so. Various municipal authorities such as those of Pretoria, Johannesburg and Cape Town are reporting increasingly limited landspace for waste (Bondolfi, 2007). There are increasing concerns regarding the leaching of hazardous metals such as chromium, mercury and cadmium from landfill waste, especially electronic and electric wastes ? the so-called eWastes. In more developed countries such as the United States of America and Western Europe the problem of eWaste has grown to the extent where legislation has been enacted, such as the Waste Electrical and Electronic Equipment (WEEE) legislation of the EU (European Union Directive 2002/96/EC). The 19th and 20th centuries have seen major technological advances. Relevant to this paper is the availability of centrally generated electrical power, telecommunication, entertainment through recorded and transmitted music and images, the growth and pervasive influence of electronics, and the handling of digital data by computers and microprocessors. These developments have placed ever increasing demands on resources for the manufacture of electrical and electronic equipment, as well as on the generation of electrical power. Most of the resources required are non-renewable: copper, steel, aluminium and other metals, various thermoplastic polymers such as PVC (polyvinyl chloride), polyethylene and ABS ( acrylonitrile-butadiene-styrene), thermosetting polymers such as epoxies, elastomers such as butyl rubber, glasses and ceramics, and composites such as fibre reinforced plastic (fibreglass). The conservation of non-renewable resources inevitably includes recycling. To a certain extent, recycling of materials locally is well established. Thus glass, paper, used oil, car batteries, ferrous scrap such as beverage cans and non-ferrous scrap such as

Jan 1, 2007

By B. P. Watson, T. J. Maphosa, D. P. Roberts, L. J. Gardner

The results of FLAC3D modelling on chromitite Upper Group 2 Reef pillars from the Bushveld Complex of South Africa are described. The model input parameters were determined from laboratory triaxial tests with post-failure measurements. These geomechanical tests were performed on rock materials within the pillars and the immediate pillar foundations. In the models, postfailure behaviour was simulated using the concept of cohesion softening. Models were built to determine the strength and behaviour of pillars with a width-to-height ratio of approximately two. The original research aimed to find a suitable depth below the surface where Impala Platinum Ltd could safely introduce crush pillars; however, the paper only describes the model results: the ideal depth of the crush pillar introduction is not discussed. The results of the modelling are compared with the PlatMine formula for peak pillar strength and with an underground instrumented pillar located elsewhere on the same reef. Some insight into the effects of grid size on strength is also provided. Further underground measurements are recommended to verify the model results

Sep 9, 2024

By D. Marcotte, R. V. Dutaut

"In mineral resource evaluations, geostatistical methods known as global change of support allow prediction of the theoretical histogram and gradetonnage curves prior to interpolations or simulations of grades. Two methods commonly used by professionals to guide the choice of interpolation parameters and assess results are the discrete Gaussian model (DGM) and the indirect lognormal correction (IndLog). These models rely upon an estimate of the dispersion variance of the blocks, which is derived by numerical integration of the variogram model over a discretized block. Due to difficulties in obtaining well-formed traditional experimental variograms (especially in the presence of outliers and limited clustered data), many professionals prefer to use ‘normalized’ variograms such as correlogram (non-ergodic variogram), pairwise-relative, or variogram of the normal score transform. A series of simulations with different grade distributions and variogram models are used to assess the performances and robustness of the various variogram estimators with respect to the DGM and IndLog global change of support. Our results show that the traditional variogram, the correlogram, and normal score variogram have better performances, compared to pairwise, for both DGM and IndLog. Moreover, DGM provided better results than IndLog for the grade distributions that are not strictly lognormal. These findings provide valuable guides for geostatistics practitioners. IntroductionWhen reporting resource estimates,practitioners are required to follow generalstandards described in the NI43-101 (CIMguidelines), JORC, or SAMREC codes. One cangenerally recognize three main parts directlyrelated to the block model:•,Pre-processing: exploratory data analysis (EDA), domaining, capping, compositing, declustering, variography•,Processing: block size, neighbourhood, interpolation types (linear or nonlinear)•,Post-processing: classification, reporting.Pre-processing aims to simplify and strengthen the processing step. Ideally, domaining, capping. and compositing is aimed at defining a single homogenous population. During the processing phase, a common practice is to use a block size corresponding to the planned selective mining unit (SMU). In most precious metal deposits (gold, notably), the SMU size is frequently smaller than the recommended half data spacing (Journel and Huijbregts 1978), resulting in high estimation variance and either a high degree of smoothing if the regression slope is managed or a high degree of conditional bias if it is not. Most actual resource estimates are made using block sizes between one-quarter to one-sixth of the average data spacing, sometimes even smaller. In addition to the block size, the interpolation choices for the neighbourhood selection and interpolator (e.g. inverse distance (ID) or ordinary kriging) are often based on the Qualified Person’s (the QP) experience and some basic validation plots that often do not consider the conditional bias (e.g. trends or SWATHs plots, which are designed to compare two sets of population using a one-dimensional graph)."

Jan 1, 2018

By H. Griesel

The overall supply of platinum is forecast to rise more than the demand, and market deficit will narrow somewhat, but is still substantial at about 480 000 ounces. Because of this deficit, the price of platinum is expected to remain high, not taking into account the impetus from funds and speculators. With this strong demand for platinum and the high price, platinum producers still need to initiate projects to not only sustain current production, but also expand output into the high demand. However, the rise in the platinum price does not entirely offset the drop in revenue due to the strong rand. Consequently, in the current economic environment, executives and managers are under extreme pressure to initiate only the highest yielding projects and implementing them successfully. During the initiation phase of a project, the cost of changing concepts is the least, and strategic project decisions are the most important. It is during this phase that the most value can be added to a project, therefore requiring inputs from highly skilled, creative and experienced people. This paper will discuss thought processes and paradigms during the initiation of projects that will assist project owners in the selection and initiation of successful and profitable projects. The project initiation process will also be discussed outlining selection models, risk analyses and funding considerations.

Jan 1, 2004

By Simon Mundike, Muwindwa Lipalile

A scraper based block cave method has been successfully applied to extract the Lower Ore Body at Nchanga since the 1950?s. Since inception, scraper drifts and service ways have been supported using steel arch sets fabricated to a specific design from high strength manganese steel To reduce costs and to improve productivity, trials commenced in 2002 using fibre reinforced shotcrete as an alternative support method. One of the areas; the 2420 8E 1C trial drift was subjected to abutment loading for several months prior to undercutting and cave mining. Shotcrete installed exhibited minor cracking shortly after application but very little deterioration thereafter. Following the success of the trial, the application of fibre reinforced shotcrete was extended to other drifts. This paper describes the application of fibre reinforced shotcrete at Nchanga and outlines design and quality assurance methods employed.

Jan 1, 2005

By Baruch Grinbaum, Edwin Bwalya, Robert Minango, Deogratias Bukunkwe

Solvent extraction of Cu from acidic leach, using an oxime extractant, e.g. LIX 984 or Acorga is a well known and established process. As the process advances, Cu is extracted to the solvent and is replaced by H+ in the aqueous phase. At high acidity the distribution coefficient of Cu between the solvent and the aqueous phase decreases, and eventually relatively high concentration of Cu remains in the raffinate, regardless of the number of equilibrium stages. In many processes this phenomenon is immaterial, as the raffinate returns to the leaching and no copper is lost. But when the copper raffinate is used for processing of additional metals, minimal concentration of Cu in the raffinate is essential for an effective process. The recommended process includes three steps: 1. SX-1: Standard extraction of Cu with oxime. The resulting raffinate contains about 6-8 g/L Cu and 50 g/L H2SO4. 2. SX-N: Extraction of most of the acid into an amine-based solvent, and stripping it with a base, e.g. aqueous ammonia, caustic, Na2CO3 etc. The extraction removes no metals, but decreases the concentration of acid from 50 to 10 g/L. 3. SX-2: Extraction of the neutralized solution once more with oxime, to remove the residual copper. Such a process enables one to get down to 100-150 ppm Cu in the final raffinate. This process was developed and tested in the R&D facility in Chambishi Metals plc, by a joint team of Chambishi & Bateman, using Cognis LIX 984N and real solutions from the plant. In the laboratory scale, the equilibrium isotherms for SX-1, SX-2 and the neutralization were developed. Computer simulation of the results showed that the optimal configuration is two stages for both extraction and stripping for SX-1. For SX-2 2-3 stages of extraction and two stages of stripping are needed. The stripping stages may be common to both SX-1 and SX-2. The neutralization of SX1 raffinate was tested both by conventional precipitation with lime and by extraction with Alamine based solvent extraction and stripping with a solution of 10% NaOH. For the SX-N only one stage was needed for both the extraction and stripping. The bench scale pilot plant was run for both SX-1 & SX-2. The results were very similar to the simulated ones, and the configuration of 2E2S for SX-1 and 3E=2S for SX-2 delivered the required raffinate with less than 150 ppm Cu.

Jan 1, 2005

By X. B. Zhao, J. G. Cai

When stress wave propagates through fractured rock masses, the wave will be slowed and attenuated due to the presence of these fractures. If the amplitude of stress wave is large enough to mobilize nonlinear deformation of these fractures, they will present different effects on one-dimensional P-wave propagation compared with those of linear deformational fractures. The static BB model is adopted to describe the nonlinear deformational behavior. Method of characteristics combined with displacement discontinuity theory is used to build analytical solutions of wave particle velocities and wave stresses. These equations are numerically solved with sufficient accuracy.

Jan 1, 2003

By A. Peake

Background The CSIR Division of Mining Technology assumed responsibility for the operations of the Hoist Rope and Mechanical Test Laboratories at Cottesloe in April 1999. The laboratories were previously the responsibility of the CSIR’s Division of Manufacturing and Materials Technology, before which they fell under the National Mechanical Engineering Research Institute (also of CSIR). As the focus of this conference is on safety in mines research institutes, it was thought appropriate that this paper should review some of the activities at Cottesloe and its role in supporting mine safety strategies.

Jan 1, 2003

By E. Hakami

The objective of the study was to estimate the largest shear displacement that could be expected on a pre-existing fracture located in the repository area, due to the heat release from deposited waste. Two-dimensional numerical analyses using UDEC have been performed. The maximum shear displacement, at the fracture centre, amounts to 0.2 – 13.8 cm depending on fracture parameters. The fracture extension, friction angle and shear stiffness are found to be the most important. Le but de cette étude est de déterminer le déplacement maximal en cisaillement qui puisse se développer le long d&apos;une fracture préexistante en réaction à la chaleur dégagée par les déchets radioactifs enfouis dans la roche. Les analyses numériques ont été réalisées à l&apos;aide du code 2D UDEC. Le déplacement maximal en cisaillement enregistré au centre de la fracture varie entre 0.2 et 13.8 cm en fonction des propriétés de la fracture. L&apos;ouverture, l&apos;angle de friction et la rigidité au cisaillement semblent avoir une influence dominante sur les résultats. Zielsetzung der Studie war die Abschätzung der maximalen Scherverschiebung, die auf einer innerhalb des Endlagergebietes existierenden Rissfläche infolge der Wärmeabstrahlung des eingelagerten Materials zu erwarten war. Es wurden zwei-dimensionale numerische Berechnungen mit UDEC durchgeführt. Die maximale Scherverschiebung im Zentrum der Rissfläche beträgt 0.2-13.8 cm, abhängig von den Risseigenschaften. Dabei hat sich herausgestellt, dass Rissgrösse,Reibungswinkel und Schersteifigkeit den grössten Einfluss haben.

Jan 1, 2003