VOLUME 47 . DECEMBER 2016 INSIDE: Shale gas developments in Shale gas developments in the the Karoo Basin Karoo Basin I 1 Doug Cole/Haajierah Mosavel Characterisation of surface dust and trapped dust samples around some asbestos mine dumps in Mpumalanga Province, South Africa I 3 Maphuti Kwata The all new Young Geoscientists’ Network I 4 Refilwe Shelembe Core logging team at borehole site KWV-1 near Willowvale in the Eastern Cape (left to right): Cecil Tivani (UJ), Claire Geel (UCT), Haajierah Mosavel and Doug Cole. First South Africa–Canada Bilateral Collaboration Workshop I 5 Refilwe Shelembe In 2015 and 2016, the Council for subsequent laboratory measurements Geoscience undertook a collaborative of residual gas and Rock-Eval analysis. project with the Karoo Research Initiative Shallow groundwater was sampled from New book on the Bushveld (KARIN) under the auspices of CIMERA wind pumps within a 10 km radius of Complex I 7 (DST-NRF Centre of Excellence for borehole KZF-1 and from boreholes and Maria Atanasova Integrated Mineral and Energy Resource rivers within a 10 km radius of borehole Analysis) with a view to investigating the KWV-1. Artesian water emanating from shale gas potential and the properties depths of between 560 and 670 m in Annual Conference 2017 I 8 and distribution of shallow and deep borehole KZF-1 was sampled, but no groundwater in the Karoo Basin. deep artesian water was encountered in borehole KWV-1. Laboratory Services – new Methane gas is known to occur in the instrumentation I 8 Ecca Group shale of the Karoo Basin. Borehole KZF-1 which had been drilled The Whitehill Formation provides the to a total depth of 671 m intersected best target for shale gas since it has 657 m of Ecca Group shale overlying similar total organic carbon contents to 14 m of Dwyka Group diamictite at several gas-producing shales in the USA the base of the borehole. No dolerite and maturity levels conducive to the was encountered. Black carbonaceous production of dry gas. shale of the Whitehill Formation was intersected at three intervals due to The investigation focussed on core tectonic duplication caused by thrusting. retrieved from two deep boreholes in the Thicknesses from the top downwards Tankwa Karoo (KZF-1) and the vicinity were 19.5 m, 36.25 m and 2.45 m. of Willowvale (KWV-1) in the Eastern Cape Province. Carbonaceous shale The desorbed gas measurements are from the Ecca Group was sampled for very low for the Ecca Group shales, with desorbed gas in the field and sealed for the highest value being 0.047 m3 of gas CGS 2016_ Geoclips - Vol 47_ December 2016_ 21-11-2016_ v1.indd 1 2016/11/30 01:39:17 PM 2 I GeoClips per tonne per day from the Whitehill Formation. Only the Whitehill Formation was sampled for residual gas, with the highest value recorded being 0.56 m3 of gas per tonne, with methane contributing 86 %. The results of the Rock-Eval analysis indicated that the shales are overmature and have a low potential for shale gas. Borehole KWV-1 was drilled to a total depth of 2 353 m and intersected 410 m of dark-grey shale of the Fort Brown Formation, 13 m of black carbonaceous shale of the Whitehill Formation and 31 m of dark-grey shale of the Prince Albert Formation overlying 15 m of Dwyka Group diamictite at the base of Drilling rig and core boxes at the KWV-1 site near Willowvale. the borehole. 1 245 m of sandstone, rhythmite and shale of the Ripon Formation occur between the Fort Brown and Whitehill Formations. Several dolerite sills up to 150 m intrude the entire Karoo succession. Gas contents are very low with no residual gas present. The highest total gas value recorded was only 0.2 m3 of gas per tonne, derived from a sample of carbonaceous shale from the Ripon Formation. The results of the Rock- Grey shale containing abundant lighter-coloured tuff beds of the Collingham Formation overlying black Eval analysis indicated that the shales carbonaceous shale of the Whitehill Formation at 420.46 m depth. A sample of the Whitehill Formation was are overmature, probably as a result of removed for gas analysis. deep burial and thermal metamorphism associated with dolerite intrusion. The quality of the shallow groundwater around the KZF-1 borehole site was found to vary significantly, ranging from good-quality potable water to brackish water with elevated Na, Cl and HCO3 concentrations. The shallow groundwater and surface water in the vicinity of the KWV-1 borehole site was found to be of good quality, based on pH and electrical conductivity measurements. The deep artesian groundwater sampled from borehole KZF-1 consisted of good-quality groundwater emanating from brecciated Prince Albert Formation shale at 560 m depth and brecciated Dwyka Group diamictite at 671 m depth, interspersed with sulphurous groundwater from brecciated Prince Albert Formation pyrite- rich shale at 634.44–637.44 m depth. The shale gas potential of the Ecca Group shales, including the Whitehill Formation in the two boreholes, was found to be minimal. The shales Shallow groundwater sampling from a borehole near Willowvale with Kate Robey, Doug Cole and Haajierah were found to be overmature owing Mosavel. CGS 2016_ Geoclips - Vol 47_ December 2016_ 21-11-2016_ v1.indd 2 2016/11/30 01:39:18 PM Geoclips - Volume 47 - December 2016 GeoClips I 3 to tectonometamorphic overprinting deep groundwater for the first time. associated with the Cape Fold Belt in This will be a requirement for future For more information contact: the case of KZF-1 and deep burial and regulations, should hydraulic fracking Doug Cole/Haajierah Mosavel thermal metamorphism from dolerite in for shale gas proceed. Knowledge Mapping Geology the case of KWV-1. of the deep groundwater properties +27 (0)21 943 6700 will facilitate empirical investigations [email protected] This research is important, as it into the possible contamination of the [email protected] allowed for the sampling of in situ shallow groundwater. Characterisation of surface dust and trapped dust samples around some asbestos mine dumps in Mpumalanga Province, South Africa The mining of asbestos in South Africa started in the 1800s and ceased in 2002 because of environmental and health reasons. Large operations of asbestos mining in South Africa took place in the Northern Cape, Limpopo and Mpumalanga Provinces. It is an environmental concern that numerous asbestos mine dumps situated in close proximity to human settlements in the Mpumalanga Province have remained unrehabilitated. Asbestos particles are microscopic in size and can be lifted from ground-based sources by wind erosion or during excavation processes. The purpose of this investigation is to characterise surface dust and trapped dust samples around human Location of the sampling sites in the Mpumalanga Province. settlements that are close to ownerless and abandoned mine dumps. Thus, samples were collected from five sites, with three of these sites (A, B and C) situated close to Mbombela (previously Calcite named Nelspruit), the capital city of Mpumalanga Province. A fourth site, D, Plagioclase is close to Malelane on the eastern side m/m % of Mbombela near the Mozambique Quartz border gate, while Site E is located to Chlorite the southwest of Mbombela. Amphibole The geochemistry results indicate the presence of oxides of Si, Ti, Al, Fe, Serpentine Mn, Mg, Na, K, P and Cr metals which confirms the predominance of silicate Talc minerals, as indicated by the following measurements: SiO2 (28.78 to 62.3 %), Fe2O3 (9.61 to 38.45 %) and MgO Sampling points (14.94 to 41.2 %). The dominant minerals measured were chlorite (Mg,Fe,Li)6AlSi3O10(OH)8, Mineralogy data. CGS 2016_ Geoclips - Vol 47_ December 2016_ 21-11-2016_ v1.indd 3 2016/11/30 01:39:18 PM 4 I GeoClips quartz (SiO2), plagioclase (NaAlSi3O8) semirectangular. The size particle (Mg,Fe,Al)5(Al,Si)8O22(OH)2) and mica and serpentine (Mg3(OH)4(Si3O5). range measured 70 µm to 100 µm (KAI2(Si3AIO10)(OH)2. The non-silicate The other minerals detected in low for granular, 100 µm to 200 µm for minerals were calcite (CaCO3), feldspar concentrations were calcite (CaCO3) semitriangular and 200 µm to 500 µm ((KAISQ3O8)-(CaAI2Si2O8)), dolomite and talc ((Mg3[Si4O10](OH)2). for semirectangular minerals. (CaMg(CO3)2 and clinopyroxene ((Ca, Mg, Fe, AI)2(Si ,Al)2O6)). The shapes of the amphibole The SEM-EDS data confirmed the and serpentine minerals detected presence of quartz (SiO2), serpentine The results confirm the predominance were granular, semitriangular and (Mg3(OH)4(Si3O5)), amphibole (NaCa2 of silicate minerals in trapped and surface dust samples. The significant levels of amphibole and serpentine asbestos minerals measured suggest Composition A B C D E an increased risk of contamination to SiO2 37.17 28.78 33.62 62.3 33.41 the nearby communities. TiO2 0.21 0.4 0.05 0.59 0.02 Al2O3 4.87 5.32 1.96 13.4 1.39 Fe2O3 4.48 38.45 9.61 8.01 6 MnO 0.247 0.279 0.079 0.159 0.114 MgO 32.02 14.94 40.94 2.2 41.2 CaO 0.84 0.35 0.01 1.39 0.37 For more information contact: Na2O <0.01 <0.01 <0.01 1.08 <0.01 Maphuti Kwata K2O 0.02 0.23 <0.01 0.74 <0.01 Sustainable Resources and P O 0.046 0.144 0.02 0.176 0.014 2 5 Environment Cr O 0.387 0.393 0.644 0.205 0.229 2 3 +27 (0)12 841 1387 Total 99.64 99 99 99.9 100.2 [email protected] Geochemistry data for sites in the Mpumalanga Province.