Magister Scientiae - MSc / The Morokweng impact structure which is located in the North West province of South Africa, has attracted attention as a potential host for Ni-PGE mineralization. Geochemical exploration techniques using hydroxylamine partial extraction were used to determine the nature and source of surface geochemical anomalies known to occur in the overlying aeolian sang regolith. About 40 aeolian samples were taken from an area of about 35 square kilometer, located in the north eastern sector of the Morokweng impact structure. The samples were sieved to various grain size fractions and partially extracted using varying concentration of hydroxylamine hydrochloride at 50° / South Africa

The Mount Ayliff Complex (MAC) is situated on the border between Kwa-Zulu Natal and the Eastern Cape provinces in the Republic of South Africa, approximately 90 km due west of Port Shepstone. The Complex forms part of the Karoo Igneous Province and includes five lobes (Ingeli, Insizwa, Tonti, Tabankulu, and Horseshoe) that are the remnants of a single continuous intrusive sheet that had an original extent of 18,000km2• The current outcrop is estimated at 800km2• The lobes all show extensive internal differentiation, from basal ultramafic cumulates to diorites and monzonites at the top, while most other intrusions in the Karoo Igneous Province cooled rapidly enough to produce relatively homogenous dolerites. Most work conducted on the Complex thus far has centered on the Insizwa lobe due to the presence of a Ni-sulphide occurrence near the base of the lobe at Waterfall Gorge. The setting of the ores has analogies to the Noril'sk-Talnakh deposits, which has raised considerable exploration interest on the Mount Ayliff Complex over the last century. The current study investigates the Ni-Cu sulphide potential of the Ingeli and Horseshoe lobes, which have been poorly studied in the past. To this effect, a stream sediment survey was conducted around the Ingeli lobe to try and detect potentially hidden magmatic sulphide ores. Further, the five lobes of the Complex have been compared in terms of lithology and lithogeochemistry. Analytical techniques used for the current study include: XRF, ICP-MS and electron microprobe. Stream sediment samples were analysed using XRF and ICP-OES. Olivines from the ultramafic cumulates of the Ingeli and Insizwa lobes are undepleted in Ni, whereas olivines from the Horseshoe and Tabankulu lobes are strongly depleted in Ni. This suggests that the rocks of the latter two lobes crystallized from parental magmas that interacted with a sulphide liquid and that the magmatic flow direction was from the north to the south. The data indicate that the ultramafic rocks of the Complex plot on or near control lines between olivine and Karoo dolerite indicating that the rocks are mixtures of cumulus olivine and trapped melt of Karoo dolerite composition. There appears to be a copper enrichment towards the top of the ultramafic package in the Ingeli lobe. This pattern corresponds to other studies conducted in the InsiZWa lobe and suggests that the two lobes had originally been connected. The lowermost cumulates of the Ingeli lobe contain an enhanced crustal component suggesting some in situ contamination. No significant sulphide enrichments were encountered in the Basal Zone rocks of the Ingeli lobe. However, the stream sediment data indicate localized PGE enrichment indicating the possible presence of a localized hidden sulphide occurrence of the type found at Waterfall Gorge. Small amounts of sulphides were found associated with the Basal Zone rocks in the Horseshoe lobe consistent with the trends of Ni-depletion of olivines. However, a lack of Co depletion in the ultramafic rocks of this lobe suggests that any sulphide segregation event that did take place was of a relatively small scale. / Dissertation (MSc)--University of Pretoria, 2006. / Geology / MSc / Unrestricted

<p>The Morokweng impact structure which is located in the North West province of South Africa, has attracted attention as a potential host for Ni-PGE mineralization. Geochemical exploration techniques using hydroxylamine partial extraction were used to determine the nature and source of surface geochemical anomalies known to occur in the overlying aeolian sang regolith. About 40 aeolian samples were taken from an area of about 35 square kilometer, located in the north eastern sector of the Morokweng impact structure. The samples were sieved to various grain size fractions and partially extracted using varying concentration of hydroxylamine hydrochloride at 50&deg / C.</p>

<p>The Morokweng impact structure which is located in the North West province of South Africa, has attracted attention as a potential host for Ni-PGE mineralization. Geochemical exploration techniques using hydroxylamine partial extraction were used to determine the nature and source of surface geochemical anomalies known to occur in the overlying aeolian sang regolith. About 40 aeolian samples were taken from an area of about 35 square kilometer, located in the north eastern sector of the Morokweng impact structure. The samples were sieved to various grain size fractions and partially extracted using varying concentration of hydroxylamine hydrochloride at 50&deg / C.</p>

MESMEG / Department of Mining and Environmental Geology / This study entails geochemical and mineralogical characterization of gold tailings of Nestor Mine and Glynn’s Lydenberg Mine of the Sabie-Pilgrim’s Rest goldfields. A total of 35 samples were collected and were analysed for chemical composition (XRF and ICP-MS), mineralogical composition (XRD). In addition, acid-base accounting (ABA) techniques had been conducted to predict the potential for acid mine drainage. Seepage from Nestor tailings dump and water samples from the adjacent Sabie River were also collected and analysed by means of inductively coupled plasma mass spectrometry (ICP-MS) and immediate constituent (IC) -analytical techniques. The study revealed that Sabie-pilgrim’s rest goldfield is characterized by both acid generating and non-acid producing tailings, and this is attributed to variations in the mineralogy of source rocks. Gold occurred within the Black Reef Quartzite Formation in the Nestor Mine and within the Malmani Dolomite in the case of Glynn’s Lydenburg Mine. Mineralogy and bulk geochemical analyses performed in this study showed a clear variation in the chemistry of Nestor Mine and Glynn’s Lydenburg Mine tailings. Predominant oxides in Nestor mine tailings samples are SiO2 (ranging from 66.7-91.25 wt. %; followed by Fe2O3 and Al2O3 (in range of 0.82-15.63 wt. %; 3.21-12.50 wt. % respectively); TiO2 (0.18-10.18 wt. %) and CaO (0.005-3.2 wt. %). Also occurring in small amounts is CaO (0.005-3.2 wt. %), K2O (0.51-2.27 wt. %), MgO (0.005-1.46 wt. %), P2O5 (0.029-0.248), Cr2O3 (0.013-0.042 wt. %) and Na2O (0.005-0.05 wt. %). The samples also contain significant concentrations of As (137-1599 ppm), Cu (34-571 ppm), Cr (43-273 ppm), Pb (12-276 ppm), Ni (16-157 ppm), V (29-255 ppm), and Zn 7-485 ppm). In the Glynn’s Lydenburg Mine tailings SiO2 is also the most dominant oxide ranging between 47.95 and 65.89 w%; followed by Al2O3 (4.31 to 16.19 wt. %), Fe2O3 (8.48 to 11.70 wt %), CaO (2.18 to 7.10 wt. %), MgO (2.74 to 4.7 wt. %). Occurring in small amounts is K2O (1.12-1.70 wt. %), MnO (0.089-0.175 wt. %), P2O5 (0.058-0.144 wt. %) and Cr2O3 (0.015-0.027 wt. %). Arsenic (As), is also occurring in significant amounts (807-2502 ppm), followed by Cr (117-238 ppm), Cu (10-104 ppm), V (56-235 ppm), Ni (45-132 ppm), Pb (13-63 ppm) and Zn (90-240 ppm). Nestor Mine tailings associated with Black Reef Formation mineralization have net neutralizing potential (NPR) <2, hence more likely to generate acid; and their acid potential (AP) ranges 1.56 to 140.31 CaCO3/ton and neutralizing potential (NP) range from -57.75 to -0.3 CaCO3/ton. Glynn’s Lydenburg Mine tailings dump which is vi associated with dolomite mineralization, however, was not leaching acid. Based on acid-base accounting results, these tailings have more neutralizing potential (ranging between 57.6 and 207.88 CaCO3/ton) than acid potential (ranging between 7.5 and 72.1 CaCO3/ton); and their NPR>2, hence unlikely to produce acid. This is confirmed by paste pH which was in the ranges between 7.35 and 8.17. Tailings eroded from Nestor Mine tailings dump were also found to be characterized by high content of metals and oxides, namely, As, Cu, Ni, Pb, V, and Zn with SiO2, Fe2O3 and TiO2. The tailings were observed eroded into the Sabie River where AMD related precipitate (yellow boy) was also observed, indicating further oxidation downstream. Field observations, onsite analyses of water samples and laboratory results revealed that Nestor Mine tailings storage facility discharges acid mine drainage with considerable amounts of Al, As, Cu, Fe, Mn, Zn and SO4 and very low pH exceeding the limit as per South African water quality standards. High concentrations of these metals have toxicity potential on plants, animals and humans. Upon exposure to oxygen and water, tailings from Nestor Mine are more likely to generate acid mine drainage that can cause detrimental effect to the environment and the surrounding communities. Potential pollutants are Fe, Mn, Al, As, Cr, Cu, Ni and Pb. Tailings from Glynn’s Lydenberg showed no potential for acid mine drainage formation. / NRF