MESMEG / Department of Mining and Environmental Geology / Giyani Greenstone Belt is known to host significant amount of gold of which about 10 tonnes were extracted from the belt in the 19th century. Due to increased gold price and mining practices that make it economic to mine low-grade ore deposits, major gold deposits within the belt have been the main targets for exploration while Nebulas Prospect remain unnoticed. To make the Nebulas Prospect attractive for investment, its gold mineralization potential needed to be investigated. The main purpose of this study was to conduct assessment of the probable gold mineralization in the Nebulas Prospect and its economic viability. The specific objectives were to establish the gold mineralized zones within the Nebulas Prospect, develop a geological model showing the geometry and placement of gold in the subsurface, establish gold grade distribution and its economic implication, and select the most appropriate and practical mining method for exploitation of the established gold deposit. The research approaches used in achieving these objectives comprised of knowledge driven predictive modelling of Nebulas Prospect to derive prospectivity map demarcating the area with the potential of hosting gold mineralization. Magnetic survey was conducted in geological permissive areas, thereby establishing boundaries of mineralization, both lateral and vertical. Geological and subsurface gold grade distribution were carried out by means of trenching and pitting. The integration of the geological, geophysical and geochemical data using Geosoft 8.5 and ArcGIS 10.5 assisted in development of a gold deposit model that model illustrates distribution and concentration of gold. Results of the investigation reveals that Banded Iron Formation (BIF) dominates the southern part of the study area while quartz vein and schist dominate the northern part. The application of knowledge driven predictive modelling established mineral prospectivity map for Nebulas Prospect, which narrowed the potential area for further investigation. The area located outside the boundary of prospective area indicated low mineralization potential compared to highly mineralized zone within geological permissive boundary. The two mineralize zones which exits in the Nebulas Prospect are separated by pegmatite intrusion which is observed from magnetic data presentation. The gold is hosted within BIF, schist and quartz vein. The highest concentration observed value of 10.65 g/t is hosted in serpentine schist and lowest significant of 1.24 g/t in BIF. The gold grades are higher in schists than in BIF and quartz veins. The Nebulas Prospect present significant measured iv gold mineral resource with substantial economic potential. The evaluation of the technical aspects of the Nebulas Gold Deposit, which include grade and tonnage was estimated through longitudinal vertical section method. The gold hosted within Banded Iron Formation (BIF) comprise a measured gold resource of 6957.6 t at an average weighted grade of 2.22 g/t Au. However, the gold mineralization hosted within tremolite-mica schist, serpentine schist and quartz veins comprise a measured gold resource of 3919.37 t with average grade of 3.8 g/t Au. The Nebulas Gold Deposit contain a significant grade and tonnage. At an assumed currently economically mineable cutoff grade 1 g/t Au, Nebulas Prospect has a measured resource of 10877 t at a weighted average grade of 2.79 g/t Au. Analytical hierarchy process (AHP) was used to prioritize the factors affecting mining method selection and ranking of potential mining method, technically appropriate for the established gold deposit in Nebulas Prospect. Open pit mining method was identified as appropriated for extraction of the Nebulas Gold Deposit. / NRF

MENVSC / Department of Ecology and Resource Management / Mining has historically been the mainstay of the South African economy and has both shaped its social and environmental fabric. However, it has left the country with a negative legacy of abandoned mines that present environmental problems, and public health and safety concerns. The common physical and environmental problems of most of these abandoned mines are associated with open shafts, unstable slopes of waste dumps and pits, and dilapidated mine infrastructure. Even though the problems of these abandoned mines are known, little has been done to rehabilitate these mines. Some attempts have been made to rehabilitate mine openings but efforts to rehabilitate features such as mine waste dumps and dilapidated infrastructure has been woefully inadequate. The reasons for ineffective rehabilitation measures may include inappropriate measures that are used in rehabilitation of the abandoned mines, lack of financial resources to carry out the rehabilitation and the need to prioritize abandoned mine features and mine sites for rehabilitation in view of the fact that there are many of these abandoned mines that require urgent attention and resources to rehabilitate them are limited. It is therefore important that practicable rehabilitation strategies are developed and used to rehabilitate mine features and sites to provide long-lasting solutions to the physical, environmental, and social problems. This study focused on the evaluation of strategies for rehabilitation of selected abandoned mine sites in the Giyani Greenstone Belt. The approach used in this study involved conducting a detailed field inventory and characterization to establish the nature and seriousness of the physical and environmental conditions of the selected abandoned/historic mining sites in Giyani Greenstone Belt. Field inventory and characterization involved traversing around the mine-site to locate and describe abandoned mine features. The Global Positioning System (GPS) was used in capturing the absolute location of the identified major abandoned mine features such as open mine shafts, tailings dump, and dilapidated infrastructure. Each of the identified mine features was critically analyzed by scoring and ranking the associated hazards. The scoring focused on the source of the hazard, exposure pathways, and possible damage that might be caused by the hazard. Analytical Hierarchy Process (AHP) and Pugh Matrix were used to devise a multi-criteria framework for evaluating mine site rehabilitation strategies. AHP method was utilized to evaluate the significance of the deciding factors and the Pugh Matrix to relatively compare the strategies for the selection of the appropriate rehabilitation options. The results of the study showed that the best approach to effectively address the physical and environmental hazards at Louis Moore and Klein Letaba abandoned mines of the Giyani Greenstone Belt was to give priority to extremely hazardous open mine shafts and tailings dumps. Mine shafts present a high risk of falling and drowning in water in the mine workings. Such risks are likely to lead to death with no hope of recovery of the body. The next mine features to be rehabilitated are the tailings dumps since they have relatively less physical hazards but extremely high environmental hazards. Abandoned mine infrastructure was found to be less hazardous and should, therefore, receive the least attention. The preferred rehabilitation strategies for abandoned mines features were evaluated after a comprehensive characterization of the site, this was done to ensure that the selected strategy addresses both physical and environmental problems identified on the site. Based on the results of evaluation, backfilling was selected to be the most suitable rehabilitation strategy for mine shafts as it has a very high potential to eliminate the risks of people falling into the mine shaft and the chances of water contamination by abandoned mine shafts. The most ideal rehabilitation option for tailings dumps was revegetation, since it ensures the safety of the site after implementation and minimizes the future environmental impacts such as the discharge of contaminants to the nearby environment. The most preferred rehabilitation strategy for dilapidated abandoned infrastructure in the study area was the demolition of the infrastructure, this strategy will improve the safety status of the mine sites and make the land they occupy available for other traditional post-mining land uses. It was concluded that the approach of prioritizing the extremely and moderately hazardous abandoned mine features is appropriate for use in developing countries where there are numerous abandoned mines and limited resources to rehabilitate them. This will go a long way in ensuring that characterization and rehabilitation of the abandoned mine features are effectively carried out within the constraints of resources. / NRF

No / The ESA/Roscosmos ExoMars rover will be launched in 2018. The primary aim of the mission will be to find evidence of extinct or extant life by extracting samples from the subsurface of Mars. The rover will incorporate a drill that is capable of extracting cores from depths of up to 2 m, a Sample Preparation and Distribution System (SPDS) that will crush the core into small grains and a suite of analytical instruments. A key component of the analytical suite will be the Raman Laser Spectrometer (RLS) that will be used to probe the molecular and mineralogical composition of the samples. In this work we consider the capability of the proposed Raman spectrometer to detect reduced carbon (possibly associated with evidence for extinct life) and to identify the level of thermal alteration/maturity. The Raman analysis of 21 natural samples of shale (originating from regions exhibiting different levels of thermal maturity) is described and it is shown that reduced carbon levels as low as 0.08% can be readily detected. It is also demonstrated that the Raman spectra obtained with the instrument can be used to distinguish between samples exhibiting high and low levels of thermal maturity and that reduced carbon can be detected in samples exposed to significant levels of oxidation (as expected on the surface of Mars). (C) 2014 Published by Elsevier Ltd.