No description available.

No description available.

No description available.

No description available.

No description available.

No description available.

No description available.

No description available.

M.Sc. (Geology) / This study represents the first detailed field, geochemical and geochronological study of Archaean rock units that crop out along the Ncotshane River in the southern part of Swaziland. These rock units were mapped as Mahamba Gneiss in the geological map of Swaziland (Wilson, 1982). However, field examination indicated that the area consists of a heterogeneous assemblage of serpentinite, amphibolite, gabbroic gneiss, quartzite, meta-ironstone, augen gneiss, granitic gneiss and diorite, all of which are intimately associated with weakly foliated granite and dolerite. Serpentinite is regarded to represent the metamorphosed equivalent of komatiite found in the Dwalile Supracrustal Suite, a correlate of the Onverwacht Group, on the basis of similar geochemical characteristics. The silicified part of the serpentinite may compare with silicified komatiite that are widely observed in the Onverwacht Group. It is equally possible however that the ultramafic rocks originated as intrusions that are widespread in the SE Kaapvaal craton and which include both Palaeoarchaean and Mesoarchaean layered complexes. No contacts with neighbouring rocks were observed, thus not allowing unequivocal differentiation between the different possibilities. Amphibolites represent metamorphosed equivalents of the Mozaan Group basalts based on their association with Mozaan quartzite. Gabbroic gneiss, which occurs in association with amphibolite, likely represents an intrusive equivalent of amphibolite.....

A research report submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science in Engineering. Johannesburg, 2017 / The study sought to establish the applicability of rock mass classification as a primary input to wall control blasting. Conventional rules of thumb are used to develop blast designs based on parametric ratios with insufficient consideration of the rock mass factors that influence the achievability of final wall designs. Control of the western highwall of the Phoenix pit had proven to be challenging in that the designed catchment berms and wall competence were perpetually unachievable from the pit crest to the current mining levels. This exposed the mining operation to safety hazards such as local wall rock failure from damaged crests, frozen toes and rolling rock falls from higher mining levels. There was also an effect of increased standoff distances from the concerned highwall which reduce the available manoeuvring area on the pit floor and subsequently the factor of extraction that is safely achievable. The study investigated the application of rock mass classification and the Blastability Index (BI) as a means to improve wall control. This was achieved by establishing zones according to rock type forming the western highwall rock mass wherein distinguishing rock mass classification factors were used to establish the suitable wall control designs through a Design Input Tool (DIT). The DIT consolidated rock mass classification methodologies such as the Geological Strength Index (GSI) and the Rock Mass Rating (RMR) and related them to the BI and discontinuities of the rock mass to produce a tool that can be used to develop objective wall control designs. The designs driven by the tool inherently take into account the rock mass characteristic factors at the centre of rock mass classification methods and significantly reduce the dependence on rule of thumb. It was found that this approach yields designs with powder factors that are consistent with the rock breaking effort and the behaviour of discontinuities while remaining biased towards preservation of perimeter wall rock. / MT 2017