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The three most common rock mass classification systems in use in the South African mining industry today are Bieniawski’s (1976) Geomechanics or RMR System, Barton et al.’s (1974) Q-System and Laubscher’s (1990) MRMR System respectively. Of these three systems, only the MRMR Classification System was developed specifically for mining applications, namely caving operations. In response to the increased use of the MRMR Classification System in the mining industry, and concerns that the MRMR System does not adequately address the role played by discontinuities, veins and cemented joints in a jointed rock mass, Laubscher and Jakubec introduced the In-Situ Rock Mass Rating System (IRMR) in the year 2000. A quantitative comparison of the MRMR and IRMR Classification Systems has been undertaken to determine a correlation between the two classification systems, the results of which indicate that there is not a major difference between the resultant rock mass rating values derived from the two Classification Systems. Therefore, although the IRMR System is more applicable to a jointed rock mass than the MRMR System, the MRMR System should not be regarded as redundant, as it still has a role to play as a mine design tool.

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The Torlesse composite terrane is an important geological unit in Canterbury, New Zealand, making up the backbone of the Southern Alps. It consists of a large group of rock that exhibits a range of engineering geological conditions. This study has been undertaken to characterise the range in engineering geological conditions throughout the Torlesse of Canterbury in order to develop a rock mass classification scheme specific to this abundant and complex rock type. The classification is aimed to aid in TBM tunnelling assessment in the Torlesse, which enables sub-division of an area or tunnel alignment into rock mass domains. Furthermore the classification enables the prediction of rock masses through geological controls in areas of poor outcrop coverage. Four sites throughout Canterbury were selected for mapping to represent Torlesse terrane types, metamorphic facies and a range of regional fault settings: the Elliott Fault, Hurunui River, Ashley River Gorge and Opuha Dam. A preliminary desktop study was carried out with a landscape lineation analysis to develop 1) a conceptual geological model at each study site and 2) field mapping sheets to provide a check list to ensure consistency of information collected between outcrops and sites. Lineations and conceptual models identified a series of structural blocks within sites, which were further validated by field mapping. Outcrop field mapping was carried out across selected extents of study sites using the field sheets from the desktop study. Using NZGS (2005) and ISRM (1978) derived parameters, rock mass characteristics, including lithology and defect information, were recorded on the field sheets. A laboratory testing programme on selected outcrop intact rock was undertaken to support field work and later classification development. Data from field work was plotted to derive rock mass trends. Trends were used to develop a classification framework. It was found the rock mass could be defined by bedding thickness, degree of fracture and the combination of discontinuities such as persistent jointing and shearing, which defined dominant rock mass control. The rock mass could therefore be classified based on: blockiness, defined by bedding thickness and density of non-systematic jointing (fractures); and defect structure, defined by the combination of systematic discontinuities such as persistent jointing and shearing. The two principle rock mass governing controls were related together on an XY plot to form the conceptual Torlesse rock mass classification (TRC). Six classes encompassing the range of conditions observed in the Torlesse were devised for blockiness and defect structure. Blockiness classes range from: thickly bedded to massive sandstone with slight to moderate fracture, to very thin to thin bedded sandstone that is fragmented. Defect structure classes range from rock masses defined by: dominant systematic, persistent jointing with rare faulting, to rock masses typical of major shear zones, where material geotechnically behaves as a soil with no principle defect sets. Individual outcrop plotting then allowed rock masses typical of each site to be grouped on the TRC. Clusters of each study sites’ outcrops were overlaid to characterise all rock mass types observed throughout this research. This allowed representative identification of eight distinctive rock mass types (Types 1-8) that are indicative of the Torlesse composite terrane of Canterbury. Each type has a series of geological controls that influence the nature of the rock mass. Geological controls can aid in the prediction of rock mass conditions for tunnel alignment selection. Lithostructure and proximity to major structures were defined as major rock mass type controls. Lithostructure defines the effect of lithology on bedding thickness and fracturing by non-systematic jointing. Medium to massive bedding as part of rock mass Types 1 and 2 result in the best rock mass. In the sandstone-rich rock mass, systematic jointing dominates with less shearing and faulting and a lower occurrence of short, discrete, non-systematic jointing. Conversely, the thinly bedded Torlesse represented by rock mass Type 5 lacks persistent jointing. This type, being mudstone dominant, fractures more easily, is characterised by short, discrete jointing, and tends to localise faulting, shearing and some folding. Modern tectonic stress fields are also a major control. The size of the tectonic structure can impact different volumes of rock. Rock outside the direct fault zone can also be impacted giving rise to rock mass Type 6. For example, increased levels of shearing are observed in adjacent rock at both the Elliott and Opuha Dam Faults. Rock mass Types 7 and 8 represent the rock masses directly affected by large tectonic structures. Sub-dividing proposed tunnel alignments by rock mass type allows assessment of tunnelling parameters. Dependant on project specific rock mass types expected, different TBM design will be suited. This has significant implications on support measures. Open gripper TBM’s are likely to be suited to rock mass Types 1 and 2. This rock mass is expected to represent the best rock mass stability but will be the hardest to excavate. As a result, rock bolt, mesh and shotcrete will likely prevent significant block failure through gravity release. Rock mass Types 3 and 4 are expected to represent a favourably interlocked rock mass, resulting in increased penetration rate but whose advance rate is likely to be hindered by the need for more extensive support. As rock mass Types 5-8 increase in abundance, shielded TBM’s will likely be best suited due to questionable thrust generation and support requirements toward the poorer rock masses. Penetration rates will be high but advance rates are expected to be low. Significant potential for failure exists in the poorer rock mass types without adequate support, including running ground. The selection of a shielded or gripper TBM will depend on the proportion and lengths of each TRC rock mass type anticipated along a tunnel alignment. The opportunity exists for future work to refine and validate the TRC classification through increased data input, more extensive laboratory testing and its application to tunnelling projects. Furthermore it is hoped the TRC can be used for other types of geotechnical applications, at a variety of scales where Torlesse is concerned. To do this the TRC interpretations with respect to rock mass behaviour must be adapted to different scales.

Erodibility is an important factor in studies of geomorphology. Along with other factors such as climate, time, and tectonics, it contributes to the shape and evolution of landscapes. Several methods exist to quantify erodibility that examine rock mass properties such as fracture characteristics and strength of intact rock. These systems can be used to predict such varied properties as the slope of a rock mass, the geometry of bedrock channels, and the likelihood and type of potential slope failures. Yet, these systems are limited by shortcomings such as subjectivity, limited calibration, and failing to produce reasonable predictions of slope when rocks are mechanically or chemically weak. To address these and additional issues, original and modified versions of three erodibility rating indices are applied in a variety of lithologic, climatic, and erosional environments. Ratings are compared to topography for calibration purposes and to examine whether erodibility and topography will correlate in all environments studied. Several of the techniques tested are successful at improving ratings' correlation to topography in slowly eroding landscapes, while other landscapes do not correlate to ratings. A new adjustment factor for chemically weak rocks further improves this correlation in certain environments. Finally, suggestions are made for the future use of erodibility indices that incorporate specific techniques and alterations from the study as well as general impressions from use. / Master of Science

The Eastern Black Sea region of Turkey accomodates indecent residence conditions for people owing to ground conditions comprising of volcanics and concurrent flysch, and its related irregular geomorphology. One of the important difficulties in this region is transportation. Accordingly, the ordu peripheral highway which encompasses various structures such as, open cuts, bridges, viaducts and junctions and double tubed tunnel sections which will be driven in these geological and geomorphological conditions is palnned to be constructed. In regional scale, volcanics, pyroclastics and flysch deposits often intertounge with each other even over very short distances. The accurate determination of the shear strength parameters of these lithologies is vital for the assessment of portal slope stability and support design in regards to tunnel design. Rock mass classification systems, namley, RMR, NGI Q system and GSI, have been employed to obtain the rock mass shear strength parameters. Stress analyses around the tunnel opennings have been executed through employing 2D finite element analysis in an attempt to design tunnel support. The results of the analysis have been correlated with the results obtained from the emprical methods. The overall analyses and interpretations led to the determination of the support systems to be employed during tunnel construction.

The main aim of this Thesis is to examine how the rock mass and intact rock properties influence the excavatability of rock in surface mine. One of the most important decisions in the design of surface mine is the selection of mine equipment and plant. Now that increasing effort is being invested in the design and manufacture of continuous surface miners it is appropriate to examine how their performance can be related to the physical properties of the rock mass and intact rock.Over the years many attempts have been made to develop a means of assessing the excavatability of rock. Most of them are based on an empirical rating system whilst some authorities still propose the use of seismic velocity as a direct predictor of the rippability of a rock mass. On the other hand there are a number of classical models which have been developed to define the cutting force required at the pick or tooth of continuous miners.Whilst these methods have been applied with various degrees of success to the design of excavation systems there is no generally acceptable method of defining the excavatability or cuttability of a rock mass in terms of the machine power required to generate a particular rate of production.An attempt is made to overcome this deficiency by recording the intact and rock mass properties at Limestone quarry in Retznei, Austria; Openpit Gold Mines in Meekatharra and Mt Gibson of Western Australia and Openpit Coal Mine in Air Laya, Indonesia, where VASM-2D and Bucket Wheel Excavator O&K SchRs(800/1.2)15 or O&K S630 were in use in the first mine sites and Air Laya respectively to use this data to examine the relationships between the relevant dimensionless groups developed from a dimensional analysis of the problem.The dimensionless groups are obtained by examining the factors which influence the productivity of a surface miner. These include intact rock and rock ++ / mass properties, and machine power required for a particular rate of production and lead to the development of dimensionless groups namely, Rock Cuttability Index (RCI), Rock Mass Factor (RMF), Brittleness Index (BI), Rock Excavatability Index. The monitoring of machine power was carried out at Mt. Gibson and Air Laya mines.As a part of this study, field seismic tests were carried out at Mt. Gibson and Air Laya with the intention of seeking the most appropriate method of this type of test and analysis for excavation purposes. The test results indicate that borehole tests are the most promising and the output of seismic velocity obtained from a built-in program seismograph needs further thorough examination.The analysis of field data at all the sites proved that the most appropriate measure of discontinuities in the rock mass is the mean distance between discontinuities in a direction parallel to the cutting direction of the machine.Since the lateritic rock mass is different to other ordinary rock masses, a modified RMR is proposed. This is done by adjusting classification criteria on spacing and condition of discontinuity. The results proved that the discontinuity spacing obtained from the proposed method warrants wide application of the power cutting model developed.The RMR, Q-System and Excavatability Index are used to assess the performance of the continuous surface miners investigated. The results indicated that the Excavatability Index is the most acceptable criterion for the excavatability assessment.The outcome of this research has confirmed the significance of the RCI as a predictor of cutting performance of mechanical machines. The relationship between the RCI and REI can be used to good effect in analysing the performance of operating machines. A good example of this is given in the analysis of the performance of the BWE at the Mae Moh mine in Thailand.

Measuring the shore platform width might be an effective way to measure the rate of coastal retreat. The processes controlling shore platforms are a highly debated topic throughout the coastal science community. Some researchers believe that marine processes control them and other researchers believe that physical weathering is responsible. This study determined the relationship between rock mass classification systems and shore platform widths as a diagnostic tool to predict the rate of recession. Testing took place along the Mahia Peninsula and Tatapouri on the East Coast of New Zealand. A Garmin eTrex hand-held GPS unit was used to map both the cliff base position and the edge boundary of the shore platform. Data analysis for Mahia Peninsula showed a linear relationship with a r2 value of 68% with a negative regression line. The data for Tatapouri showed that there was no linear relationship, but has an r2 value of 68% when a polynomial fit to the 2nd order was apply to the data (appendix). The estimated rate of erosion, ranges from 0.61 to 17.8 0.06 mm y-1 for Mahia Peninsula and 1.32 to 16.45 0.08 mm y-1 for Tatapouri.

The Zagros fold-thrust belt results from the continent-continent collision between the Arabian margin and the Eurasian plate following the closure of the Neo-Tethys Ocean during the Tertiary. Despite some ongoing controversies about the timing of the onset of the collision there is little doubt that the main episode of the cover shortening in the Zagros folded belt occurred since about 10 Ma as suggested by the youngest folded strata of the Agha Jari red marls. Shortening by about 70 km derived from balanced sections across the Zagros folded belt, yields shortening rates of 7 km Ma-1 consistent with the present-day rates of 0.7 cm yr-1 based on GPS studies. A major unconformity between the Agha Jari formation and the Bakhtyari conglomerates indicates that cover shortening decreased or ceased 5 Ma ago. During or since the deposition of the Bakhtyari Formation, the Zagros fold belt underwent a regional uplift whose origin still remains enigmatic. The deformation is characterized by periodic folding with axial lengths sometimes greater than 200 km. This fold geometry is outlined by the limestone beds of the Asmari Formation, which is one of the main oil reservoirs in the Zagros. The Zagros also serves as the main originating headspring of the rivers running into the Persian Gulf and Oman Sea watersheds. Among all these rivers, the major ones are: Arvand Rud, Gamasb, Karun, Rajah, Zaal and Marun join and form Jarahi, Seymareh, Qareh Aqhaj, Zohreh, Dalaki, Mend, Shur, Minab, Mehran and Naband. Therefore, the Zagros region has high potential for dam construction to control surface water for electric energy, water supply for irrigation of agricultural lands and land reclamation. Among various formations in the Zagros region, the Asmari Formation limestone with relatively exclusive characteristics such as rigidity and morphology is a suitable rock foundation for dams in the Zagros range. It should be considered that the Asmari limestones constitute a series of double plunging, asymmetrical folds with northwest-southeast trend and that the southern flanks are steeper than the north-eastern ones (70° to 90º, locally reversed). Due to varying inclinations, there are much more curvatures of strata in the southwestern flanks of folded structures, with different characteristics of the rock mass in the two flanks of the anticlines. The anticlines, particularly in the Asmari Formation, contain tension-induced, open fracturing which has introduced significant secondary permeability. Engineering geological investigations indicate that there is a clear relationship between rock mass characteristics of the Asmari Formation and tectonic activities such as various tilting and curvature rates of strata at folded structures in the Zagros Mountain range. In this regard it should be considered that the upper and middle units of the Asmari Formation that constituted the main dam foundation rock mass on the northern flanks are influenced by karstification processes which have resulted from aggressive mineral waters. Thus huge karst features and cavities can be observed, where the Gachsaran evaporites stratigraphically overlie Asmari Formation succession limestones. The aggressive mineral waters originating from the Gachsaran Formation play the main role in karstification of the Asmari Formation limestones, whereas the lower Asmari is less influenced by these solutions and karstification processes as it is restricted to where the Karun-3 and Karun-4 dams are situated. Reassessment of available data and geological investigations during this research, lead to a new proposed configuration of engineering characterization of the rock mass for the Asmari formation limestones in the Zagros Region. / Thesis (PhD)--University of Pretoria, 2012. / Geology / unrestricted