8 inside: new manager to take the council for geoscience...

VOLUME 55 . DECEMBER 2018

New manager to take the Council for Geoscience strategy forward

Valerie Nxumalo, Manager: Strategic Management

Valerie Nxumalo was born in Bushbuckridge in the Mpumalanga Province. She is a registered professional natural scientist who matriculated from Soshangana High School in 2000. Ms Nxumalo graduated from the University of the Witwatersrand with a BSc Honours degree in 2006 and an MSc degree in Geology in 2011. She started her career in 2007 as a junior exploration geologist at SRK Consulting. The focus of her work at SRK involved uranium exploration in Beaufort West. Project tasks included the logging of sedimentary rocks of the Beaufort Group in search of channel-hosted uranium mineralisation, sampling, positioning of new exploration boreholes and field mapping.

She joined the Council for Geoscience in November 2007 where she continued her investigation of Karoo rocks. Her first project at the Council for Geoscience entailed a study of the stratigraphy and sedimentology of Karoo Supergroup rocks in the Kalahari Karoo Basin of Botswana and Namibia. The purpose of this project was to develop a correlative framework for the various stratigraphic units in the Kalahari Karoo Basin and to understand the distribution of mineral resources, especially coal. Ms Nxumalo contributed to multidisciplinary projects that investigated the proposed nuclear sites in South Africa and the geology and mineral potential of the Rosendal area in the Free State Province, with a focus on uranium and molybdenum.

INSIDE:New manager to take the strategy forward I 1

A new path for digital transformation I 2

Congratulations to the MSc graduates I 2Nontobeko Scheppers

Husband and wife receive PhD degrees I 4Nontobeko Scheppers

11th ICARD/IMWA 2018 conference hosted in South Africa I 5Thakane Ntholi

Wrapping up collaboration with ENVIREE I 7Henk Coetzee

Potential of platinum group elements in the Main Zone of the Northern Limb of the Bushveld Complex I 8Alazar Yosef Billay

Go Ghaap! heritage route launch – the geology of the Ghaap plateau I 10Ponani Mthembi

The Union Buildings – An early case showing the need for pre-construction geological testing of building stones I 11Rehan Opperman

Council for Geoscience Annual Conference 2019, 11–12 February 2019 I 12

She also participated in several small commercial projects such as the classification of rock samples for road aggregate material and the 3D geological modelling of quarries.

Ms Nxumalo is currently working on a research project focussing on the nature and distribution of uranium and the provenance of the Karoo Supergroup rocks in the Springbok Flats Basin. This project forms part of her PhD research at the University of Johannesburg.

Her vision for the Council for Geoscience in her capacity as manager of the Strategic Management Office is for the organisation to continue executing its mandate as established by Geoscience Act No. 100 of 1993, as amended. This will position the organisation to contribute

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A new path for digital transformation

The newly appointed Chief Information Officer, Phineas Mogale, was born on 8 August 1973 in Soweto. He started his school career at Molalatladi Primary School in Soweto and completed Matric at Seana-Marena High School. Mr Mogale enrolled at the University of Johannesburg and completed a BCom degree.

Mr Mogale is an experienced Information Communication Technology (ICT) professional with over 20 years’ experience in financial services and consulting in the public and private sector. He brings expertise in areas of software development, governance, information systems security and ICT infrastructure and operations management.

Prior to joining the Council for Geoscience, Mr Mogale served as Chief Information Officer of the Government Pensions Administration Agency (GPAA) as well as the Government Employees Pension Fund (GEPF) where he was responsible for claims and contributions

Phineas Mogale, Chief Information Officer

Congratulations to the MSc graduates

The Council for Geoscience wishes to congratulate the staff members who recently received MSc degrees. They are Nontobeko Magwaza, Senzangakhona Ndumo and Lusunzi Rudzani.

Nontobeko Magwaza received an MSc in Environmental Chemistry from the University of KwaZulu-Natal on 18 April 2018.

Seasonal assessment of heavy metals and spatial distribution in surface water and sediments of the Msunduzi River, KwaZulu-Natal, South Africa

Nontobeko Magwaza graduated at the University of

KwaZulu-Natal, having obtained an MSc degree.

to society through integrated and multidisciplinary geosciences in order to make a meaningful impact towards improving the lives of all South Africans

by reducing inequality and poverty, contributing to clean and affordable energy, training and development, and environmental sustainability.

Nature in all its forms is close to her heart and finds expression in her keen interest in photography and the exploration of human cultures.

processing as well as the payment of claims. Under his guidance, the GPAA modernisation programme was stabilised with several subsystems developed as part of the modernisation programme being brought into production. This resulted in increased focus in regard to organisational KPIs including the reduction in turnaround time for the processing of pension claims and the cost per member.

In addition to the management of ICT infrastructure, Mr Mogale is also a member of the UNISA ICT Committee of Council where he is one of three independent external experts. The ICT Committee oversees the management of the ICT function of the university.

Over the past 15 years, Mr Mogale has established himself as a dedicated ICT leader who is passionate about technology and the opportunities it provides to uplift society. His focus has been on change management and training programmes running alongside the more technical system development

and infrastructure implementation projects. His aspiration for the Council for Geoscience is to drive digital transformation and to automate the business processes of the organisation.

Mr Mogale is very fond of his two children, a teenage girl of seventeen and a boy of ten. He spends his spare time reading and enjoys a good game of soccer or cricket.

Heavy metal pollution is a major problem facing freshwater systems worldwide. Heavy metals do not biodegrade naturally, thus they remain one of the most persistent environmental pollutants associated with anthropogenic activities. Heavy metal concentrations and some physicochemical parameters of surface water and sediments in the Msunduzi River in KwaZulu-Natal were investigated with a view to providing information on the spatial and seasonal characteristic patterns of surface water quality, concentrations, chemical speciation and the environmental risks of heavy metals in surface sediments. The metal concentrations in the water

GeoClips I 3Geoclips - Volume 55 - December 2018

Lusunzi Rudzani at the graduation ceremony of the

University of Venda where he received his MSc degree.

and sediments were quantified by inductively coupled plasma-mass spectrometry (ICP-MS), while the chemical speciation of heavy metals in sediments was evaluated following the Community Bureau of Reference (BCR) sequential chemical extraction method. The results indicated significant (p<0.05) spatial and seasonal variations in the physicochemical characteristics and heavy metal concentrations of the surface water and sediments. The water quality index (WQI) values for this river system fell within the water categories of “very poor quality” to “unsuitable for drinking”. The ecological risk index indicated that there is a low ecotoxicological risk associated with exposure to heavy metals in these sediments. The high metal concentrations revealed that increased urbanisation and industrialisation may be the main source of contamination along the Msunduzi River. Industries situated along the river which are possible contributors to pollution include chemical industries, waste water treatment plants, medical industries and electrical industries. Agricultural activities may also contribute to contamination.

Senzangakhona Ndumo obtained an MSc in Applied Geology from the University of the Western Cape on 27 August 2018.

The influence of contact metasomatism and fluid-rock interaction on the nature and style of platinum-group element

mineralisation in the Platreef, Northern Limb, South Africa: a case study from the Moordkopje farm

The complexity of Platreef stratigraphy and the generic position of Ni-Cu-PGE mineralisation present a challenge to prospecting and mining companies in the Northern Limb of the Bushveld Complex as a result of various floor rock interactions with the reef. Hence, this study evaluated the effects of contact metasomatic fluids on the nature and style of PGE mineralisation as the main event leading to the complexity of Platreef stratigraphy from the contact zone near the floor rock.

Fifty samples from two boreholes on the farm Moordkopje 813 LR for the Akanani project by Lonmin Plc were utilised in the study. The mineralogy and geochemistry of the Platreef samples were studied and associated with mineralisation occurrences.

The presence of metasomatic fluids in Platreef lithologies is indicated mineralogically by the substantial presence of quartz and geochemically by high values of yttrium and zirconium. Geochemistry was used to evaluate the effects of Archaean granite floor and calc-silicate xenoliths, respectively, by the formulated ratios K2O/TiO2 and CaO/Al2O3 and were correlated with mineralisation as Cu/Zr using down-hole plots. The correlation results showed no significant floor rock effects on the Ni-Cu-PGE mineralisation under the granite floor, in contrast to the dolomite floor where the effects enhanced mineralisation. The effects of contact metasomatism from the granite only varied the lithological units of the Platreef subsequently to complicate the primary lithological sequence which remained unresolved in this study. The shortfalls that remained unresolved are the stratigraphy of the Platreef and the position of the mineralisation related to the contact zones. These issues may be resolved by means of isotope geochemistry.

Lusunzi Rudzani was awarded an MSc degree in the Earth Sciences in Geology by the University of Venda on 21 September 2018.

Geochemical and minerological characterisation of gold mine tailings for the potential of acid mine drainage in the Sabie–Pilgrim’s Rest goldfields

The environmental hazards arising from active and abandoned mine tailings are a cause for concern. This study reports on the presence of major, minor and trace elements and primary and secondary minerals at the Nestor and Glynn’s Lydenburg Mine tailings storage facilities, Mpumalanga. The two disused mine dams, Glynn and Nestor, are approximately 6 km apart.

This study showed the availability of acid-neutralising, calcite and dolomite material at the mine tailings of Glynn that may be used to neutralise the acid generation capability of the Nestor Mine tailings. The acid-neutralising material would be able to improve the acidic Nestor Mine tailings to an almost neutral pH, which is conducive to the growth of plants and necessary for phytoremediation efforts.

The XRF results indicate that quartz is the dominant oxide at both the Nestor and Glynn’s Lydenburg Mine tailings (ranging from 47.95 to 91.25 wt%; followed by Fe2O3 and Al2O3 in the ranges 0.51 to 18.59 wt% and 1.98 to 16.19 wt% respectively). Also occurring in small amounts are CaO, Na2O, K2O, MgO, MnO, TiO2, P2O5 and Cr2O3. Trace elements such as As, Cr, Cu, Pb, V

Senzangakhona Ndumo obtained an MSc degree

from the University of the Western Cape.

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and Zn occur in substantial amounts within the tailings of the mine dams at Nestor and Glynn’s Lydenburg. The mineralogical composition based on X-ray diffraction of the bulk samples shows a wide range of primary and secondary minerals such as pyritic sulfide, quartz and mica. Calcite and dolomite are only found in the mine tailings dam of Glynn’s Lydenburg and are absent in the tailings of Nestor Mine. The study revealed that the tailings storage facilities at Nestor and Glynn’s Lydenburg in the Sabie mining area are

characterised by a potential both for acid generation and non-acid generation, which can be attributed to variations in the mineralogy of the source rocks.

The phytoremediation of Nestor Mine tailings did not succeed because the plants would not grow in acidic soils. The presence of acid-neutralising material within the Glynn’s Lydenburg Mine tailings can be used to neutralise the acid generation capability of Nestor Mine tailings. Thus, the presence of nearby acid-neutralising material, at a distance

of less than 6 km, reduces transportation and material costs. It was proven in this study that phytoremediation efforts will indeed contribute to saving the environment.

For more information contact:

Nontobeko ScheppersHuman Resources+27 (0)12 841 [email protected]

Husband and wife receive PhD degrees

Congratulations to Janine Cole and Patrick Cole, husband and wife team, for both receiving their doctoral degrees on 4 December 2018. Janine completed a PhD in Geophysics at the University of the Witwatersrand. The focus of her research was on the 3D geometry of the Bushveld Complex (BC) that has been a source of controversy for well over 50 years. Two-dimensional gravity models and magnetic models limited to short profiles in the eastern sections of the BC have been used to propose conflicting geometries for the Rustenburg Layered Suite (RLS), especially between the western and eastern lobes. One school of thought has argued for completely separate intrusions while the other school has proposed that the outcropping lobes are connected at depth. These competing models suggest different emplacement models and they provide a valuable starting point, but 2.5D potential field modelling is not well suited to modelling the complex 3D geology of the earth. In previous work, only the magnetics or gravity data were modelled independently. In this research, Janine presented the first full 3D potential field forward modelling of the central and southern Bushveld Complex. Joint 3D modelling of regional gravity and magnetic data combined with published crustal thickness models derived from broadband seismic tomography studies shows that the western and eastern lobes are broadly connected, with major disruptions largely in the eastern lobe. However, they are not separate intrusions, but represent a single magma

chamber affected by pre-existing and synmagmatic updoming. Janine imaged the possible remnants of magma staging chambers, constrained by the extent of the diffuse crust-mantle transition that underlies the whole BC. Finally, she proposed feeders correlated with the chambers in the northern lobe near the large gravity high near Polokwane and in the southeastern lobe.

Patrick Cole was also awarded a PhD in Geophysics from the University of the Witwatersrand and his research examined the modelling of potential field data, focussing on tensor magnetic

datasets. The interpretation of potential field data is fraught with challenges, ranging from inherent model ambiguity to magnetic remanence. The use of tensor-based sensors is a new technology which attempts to overcome some of the limitations of traditional magnetic or gravity surveys by measuring the full direction of the field and not just its magnitude.

Both forward modelling and inversion (in the form of source-distance calculations) were investigated, with new tensor equations being derived for tensor-based source distance calculations. The

Janine and Patrick Cole received their Doctorate degrees from the University of the Witwatersrand, focussing on

the 3D modelling of the Bushveld Complex and tensor magnetic datasets respectively.


For more information contact:Nontobeko ScheppersHuman Resources+27 (0)12 841 [email protected]

tensor forms offer the possibility of lower noise in the calculations when dealing with tensor data. The synthesis of the results from these techniques into a final model is semi-automated, allowing for the automatic determination of relevant features from the depth calculations.

Remanent magnetisation was also examined with respect to tensor data. Equations were derived to calculate magnetic field direction cosines from the tensor magnetic components. From this,

it was possible to obtain an indication of the presence of remanence, the direction of the remanent field and the complexity of remanence within bodies.

The use of actual tensor data as well as the derivation of tensor datasets from total magnetic intensity data showed that the process derived in this project is not only viable, although having some limitations, but also that it achieves good results. The extraction of valid source distance solutions from raster data is

straightforward and allows for the rapid creation of the 3D starter model for the area, from which improvements can be made through further forward modelling.

11th ICARD/IMWA 2018 conference hosted in South Africa

The Council for Geoscience participated in the International Conference on Acid Rock Drainage hosted by the International Mine Water Association (ICARD/IMWA). The conference took place at the CSIR International Convention Centre in Pretoria from 10–14 September 2018. South Africa was chosen as the venue for the 2018 event because of its mining history that dates back to the late 19th century and the fact that it plays a substantial role in the international mining sector. South Africa is faced with the challenge of abandoned mines that generate polluted mine water resulting in the deterioration of water quality. The conference covered themes such as mining for closure, water treatment processes in perspective, saline and neutral mine water, electrochemical treatment options, catchment management, economics of mine water, geochemistry/hydrogeology, prediction and mitigation. Nearly 350 experts from all over the world, including delegates from government, mining companies, universities and consultancies attended the conference, where possible remedial solutions were discussed. The Council for Geoscience was represented by the late Mr Obed Novhe and the late Ms Tlou Mashalane, as well as Mr Rudzani Lusunzi, Dr Henk Coetzee and Dr Thakane Ntholi. Five papers were published as a result of the conference. Mrs Joyce Leshomo and Ms Tebogo Mello supported the Council for Geoscience delegates at the conference. The postconference tour took place from 14–18 September and included an excursion in the Barberton area and a

visit to the Nkomati Nickel Mine. Mr Obed Novhe led the pre-conference tour to a gold mine in the area.

Highlights of the presentations given by the CGS team members are discussed below.

Geochemistry and mineralogy of precipitates formed during the passive treatment of acid mine drainage in the Ermelo coalfield, South Africa. By the late Mr Obed Novhe

This study involved geochemical and mineralogical characterisation of resulting precipitates using XRF, XRD and

geochemical speciation modelling tools to optimise a passive treatment system for acid mine drainage. Contaminants are removed as metal sulfides, sulfates and oxy-hydroxides in anaerobic units and as secondary oxides or hydroxides in aerobic units. The mineral phases formed are responsible for the attenuation of other trace elements such as Zn, Ni, Cu, Co, Pb and REE (Ce, La, Nd, Y and Yb) and also control their mobility and fate in the environment. Accumulation of chemical constituents may present an opportunity for metal recovery.

Metal removal from mine water using an integrated passive treatment

Henk Coetzee, Joyce Leshomo, the late Tlou Mashalane, Rudzani Lusunzi and the late Obed Novhe in front of

the poster presentations.

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system at the Witkrantz discharge point in the Ermelo coalfields, Mpumalanga. By the late Ms Tlou Mashalane

Passive treatment technology has been used successfully worldwide for the treatment of contaminated mine water, but its applicability in South Africa is limited. To help understand its applicability in the South African context, a pilot plant consisting of integrated anaerobic and aerobic units was operated in Carolina, Mpumalanga. The main objective was to raise the pH levels and to remove the contaminants. An overall removal rate of at least 90% was achieved for contaminants such as Fe, Al, Zn and Ni. Sulfate was removed up to 30% with no Mn removal having taken place. Deterioration of treated water is ascribed to sludge clogging and the depletion of treatment materials. Future investigations will focus on the characterisation of organic and alkaline substrates.

Acid base accounting (ABA) of mine tailings for the potential of acid mine drainage in the Sabie–Pilgrim’s Rest goldfields, South Africa. Rudzani Lusunzi; [email protected]

The study noted the availability of acid-neutralising calcite- and dolomite-bearing material at Glynn’s Mine as tailings material that can be used to neutralise the acid generation capability of Nestor Mine tailings. The acid-neutralising material is able to improve the acidic Nestor mine tailings to an almost neutral pH, which is conducive to the growth of plants necessary for phytoremediation purposes. However, the study noted that phytoremediation of the Nestor Mine tailings would not succeed because of the acidic quality of the soils. Nonetheless, the presence of acid-neutralising material within the Glynn Mine tailings can indeed be used to neutralise the acid generation capability of the Nestor Mine tailings. Thus, the presence of acid-neutralising material at a location at a distance of less than 6 km will reduce transportation and material costs. This will ensure the success of phytoremediation efforts in saving the environment and in the overall prevention of acid mine drainage.

Passive underground mine-water purification system (PUMPS): a conceptual geo-engineering model for the treatment and management of acid mine water in the Witwatersrand gold mines, South Africa. Thakane Ntholi; [email protected]

The passive underground mine-water purification system (PUMPS) is a hybrid geo-engineering model based on the mimicry of natural systems integrated with modern technologies designed for the semipassive in situ remediation of acid mine water in the Witwatersrand gold mines using sulfate-reducing bacteria and driven by geothermal energy. The model simulates reactions that occur at deep-sea hydrothermal white smokers. The mimicry of a hydrothermal system is achieved by combining three components: a low-enthalpy geothermal energy system, a reaction (bioremediation) chamber in which bioremediation takes place through sulfate reduction and a water reservoir, which together form the PUMPS.

Reconstructing historical mine water management practices for a portion of the East Rand goldfield, South Africa using long-term map and image time series. Henk Coetzee; [email protected]

Gold and uranium have been extracted from the conglomerates of the Witwatersrand since the late 19th century. The development of the mining industry, its related industries and the economic development which followed,

For more information contact:Thakane NtholiWater and Environment+27 (0)12 841 [email protected]

Joyce Leshomo, the late Obed Novhe, the late Tlou Mashalane, Frank Nkansah-Boadu (from Canada) and

Tebogo Mello participating in the Barberton Excursion.

transformed the open farmland which had existed before mining into a highly urbanised and industrialised area, with a population of over ten million people. While underground gold mining continues from rocks of the Witwatersrand Supergroup to the east, west and south of Johannesburg, formal mining ceased in the original three goldfields, the West Rand, Central Rand and East Rand, when the last mine stopped dewatering in 2010. Water inflows have been a challenge to mining since the early days, but in recent years, the rising water levels and consequent risk of pollution have received considerable attention. Historical and modern spatial data covering more than a century of mining have been compiled and used to investigate the hydrological evolution of a portion of the East Rand goldfield to unravel the engineering measures which were used to improve the management of water in the mining areas and to develop recommendations for improved water management in the future.

The Council for Geoscience regrets to announce that, subsequent to the conference, Mr Obed Nhove and Ms Tlou Mashalane were tragically killed in an accident.


Wrapping up collaboration with ENVIREE

A team from the Council for Geoscience participated in a multinational collaboration project entitled ENVIREE (ENVIronmentally friendly and efficient methods for the extraction of Rare Earth Elements (REEs) from secondary sources). The project, which had commenced on 10 October 2015, was concluded on 30 April 2018. It was coordinated by Prof. Ekberg through Chalmers University, Sweden and partners were from Poland, France, Romania, Portugal, Norway and Germany.

The aim of ENVIREE was to investigate the feasibilty of environmentally friendly methods of re-mining and processing secondary rare earth element resources.

The Council for Geoscience team was led by Dr Henk Coetzee and other members were Dr Viswanath Vadapalli, Dr Godfrey Madzivire, Mr Tshepo Motlakeng and Dr Thakane Ntholi.

The role of the Council for Geoscience was to identify secondary resources of REE in South Africa and to evaluate their potential/concentrations. This was done using hand-held XRF instruments and other laboratory methods. Additionally, the Council for Geoscience participated in the Life Cycle Asessment (LCA) section of the project where the aim was to perform studies on the environmental impacts of the environmentally friendly mining and processing methods of the REEs. Detailed sampling was undertaken on a number of mine residue deposits produced during historical fluorspar, tin, gold, uranium and pegmatite mining in the North West, Limpopo and Northern Cape Provinces.

During the course of the project, the Council for Geoscience attended project meetings in France, Portugal, Poland and the Czech Republic. These meetings included workshops and excursions related to the processing of REEs. The Council for Geoscience hosted the fifth ENVIREE project meeting from 24 to 26 April 2017 in Pretoria. The meeting included a one-day workshop

Abandoned Zaaiplaats tin mine (Photo: Tshepo Motlakeng).

The ENVIREE project meeting in South Africa.

For more information contact:Henk CoetzeeWater and Environment+27 (0)12 841 [email protected]

the Council for Geoscience participated by means of a conference call. This has been an exciting collaboration for the CGS team. As the future of energy mix indicates that there will be an increased need for REEs, it is beneficial to have CGS scientists participating in these projects.

on REEs and their beneficiation. The workshop was open to all staff members and ENVIREE members shared their expertise on various stages of REE beneficiation.

The workshop was followed by a one-day excursion to Rooiberg where Tshepo Motlakeng is currently undertaking REE work as part of his MSc studies. Here, the team collected footage of the deposits using the Council for Geoscience drone operated by Dirk Grobbelaar.

The final ENVIREE meeting took place from 21 to 24 April 2018 in Prague and

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Potential of platinum group elements in the Main Zone of the Northern Limb of the Bushveld Complex

The Northern Limb (NL) of the Rustenburg Layered Suite hosts Platreef type, chromitite layer associated type (in the Lower Zone) and Main Zone (MZ) hosted type PGE mineralisation. The MZ has been considered to be unprospective in terms of PGE mineralisation. It has been suggested that PGE mineralisation in the underlying Merensky Reef in the Eastern and Western Limbs was derived from the MZ magma. This view does not apply to the NL due to the recognition of a magmatic break between the Platreef and the MZ intrusions. Exploration and research in the NL, however, has

indicated that several PGE deposits in the NL are hosted by the MZ. These deposits include recently discovered Waterberg PGE mineralisation (below the Waterberg Group), the deposits known on several farms under the Aurora project and Moorddrift in the southwest of Mokopane.

To evaluate the PGE potential of the NL in general and the MZ in particular, simple ternary images of V-Cu-Ni and ternary images of relevant principal components (PCs) of the soil data were used to outline PGE potential zones. Vanadium (V), Cu and Ni were selected

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in respect of the spatial relationship of the high values of these elements and the known PGE occurrences. The PCs were selected based on the element associations they represent and the spatial correspondence of their signatures with known PGE occurrences.

The V-Cu-Ni ternary image shows that Platreef-type PGE mineralisation (Tweefontein area) is represented by light blue and green with bluish tint colours, MZ-hosted PGE mineralisation is represented by the green colour (A1 and A2) and chromitite-associated PGE


mineralisation in the ultramafic rocks (Grass Valley area) is represented by the bluish colour. Signatures associated with the above-mentioned types are also represented in the ternary image of PC4-PC7-PC8 as white, light blue and blue, respectively.

There are only a few PGE occurrences documented that are spatially associated with signatures A1 and A2. Classified soil data of Pt and Au of the layered suite were superimposed on the ternary image to examine whether the signatures are related to PGE mineralisation. This indicated that the signatures are associated with high Au and Pt values. However, these signatures indicating possible PGE mineralisation within the upper part of the MZ require further scrutiny with respect to two possibilities:

Classified soil data of Pt (a) and Au (b) superimposed onto a PC4-PC7-PC8 ternary image to reveal the relationship between the signatures and the high Pt and Au values.

i) The signatures reflect a pyroxenite marker similar to those in the Eastern and Western Limbs and simply reflect elevated background values for Pt and Au;

ii) The signatures reflect possible PGE mineralisation hosted by the MZ.

For the first case, a comparison with the Eastern and Western Limbs shows that the signature observed in the NL (A1 and A2) is absent in both limbs. Further, from geochemical studies of the Bellevue drillhole, it has been concluded that the pyroxenite marker is absent in the NL. Thus, signatures A1 and A2 are interpreted to reflect sulfide-PGE mineralisation. Whether the mineralisation is of economic significance requires further investigation.

It is concluded that signatures A1 and A2 in the upper part of the MZ has the potential for new discoveries of PGE (Au), that further investigation of this anomalous zone (A1 and A2) should be conducted and that the regional PGE potential zones can be outlined by a variety of data manipulation methods, in particular using those elements associated with PGE mineralisation such as Cu, Ni and V.

For more information contact:Alazar Yosef BillayEconomic Geology and Geochemistry+27 (0)12 841 [email protected]

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I GeoClips10

Go Ghaap! heritage route launch – the geology of the Ghaap plateau

In 2016, the Karoo Development Foundation (a non-profit trust) and Habitat Landscape Architects submitted a proposal to the National Lotteries Commission for funding to create a heritage route in the area south of Kuruman. The project has been strongly advocated by the Northern Cape Department of Tourism. In 2017, the Foundation received a sum of R1.8 million from National Lotteries, and the project to establish the route commenced in August. The route includes the following towns: 1. Ga-Segonyana Local Municipality: Kuruman and Mothibistad, 2. Gamagara Local Municipality: Kathu, Deben and Olifantshoek, 3. Tsantsabane Local Municipality: Postmasburg and Jenn-haven, 4. Kgatelopele Local Municipality: Daniëlskuil and Lime Acres, 5. Siyancuma Local Municipality: Griquatown and Campbell.

For more information contact:Ponani MthembiGeoscience Mapping+27 (0)15 295 3471 [email protected] Ponani Mthembi and marketing representative Rethabile Makwela attended the launch of the

newly established Go Ghaap! heritage route in the Northern Cape Province.

As part of the ten-year geoscience mapping programme, the Council for Geoscience is currently mapping part of the Griqualand West area. In July, Ms Ponani Mthembi was in the field mapping the Daniëlskuil 2823BA and Gakarosa 2723DC sheets. During this time in Kuruman, she was approached by Prof. Doreen Atkinson, who is the trustee/project manager of the Karoo Development Foundation, to give a general geology talk at the launch of the Go Ghaap! heritage route. The talk was presented under the theme Natural History: The Ghaap Escarpment and the Kaapvaal Craton.

The conference and launch of the route took place on 29 and 30 October at the Red Sands Country Lodge in Kuruman. The launch took the form of a Heritage

conference of which the main purpose was to introduce the local communities of the Ghaap region to some of the fascinating heritage resources of the area. This event was aimed at non-specialists such as municipal officials and councillors, business people, NGOs and various heritage enthusiasts.

Ms Mthembi presented key aspects of the geology of the area and the lithological units found in the region, touching on the dolomite problems the area is experiencing, but also highlighting the positive heritage sites facilitated by the weathering of the same dolomites. The presentation showcased the petroglyphs that had been discovered during the July field mapping season, the potholes/caves and the dolines. The questions following the presentation highlighted general and diverse interest in the dolomites of the area. Other speakers covered topics that ranged from rock art, the wonders of the Wonderwerk Cave, the Stone Age site at Kathu, the archaeological sites and the Langberg and Anglo-Boer battles of the Ghaap.

The presence of the Council for Geoscience at this event contributed to project stakeholder participation by increasing community awareness of the work of the organisation. The representative of Marketing and Communication, Ms Rethabile Makwela, showcased the services and current projects of the organisation in the area. Numerous stakeholders showed an interest in the work of the Council for Geoscience, as was evident from the numerous engagements and information sharing activities. The Council for Geoscience is proud to contribute to increased insights into the heritage sites of the Kuruman area.


The Union Buildings – An early case showing the need for pre-construction geological testing of building stones

The Union Buildings in Pretoria, designed by Sir Herbert Baker, one of South Africa’s most famous architects, are considered a national architectural masterpiece. The Department of Public Works (DPW) was responsible for the specifications and the management of the building contract.

The speed at which the Union Buildings building project commenced before the unification of the four colonies on 31 May 1910 is noteworthy. The decision to construct the Union Buildings was taken when it had become clear in January 1909 that Pretoria would be the administrative capital of a united South Africa. By late March 1909, Sir Baker had begun with preliminary sketch designs and Parliament approved most of the plans by 24 November 1909. Levelling, filling and excavation of the site were already underway in November 1909.

Owing to taxes received from the gold mines, the Transvaal Colony was in a better financial situation than the other colonies before unification. Some politicians suspected as early as March 1909 that the initial rush to complete the construction was because the Transvaal Colony wanted to spend as much of its money for its own benefit before unification to ensure that the Transvaal colony derived as much benefit as possible in a possible later bid to host the parliament of South Africa.

It is not known who made the original choice of using building stone for the construction of the Union Buildings, but the choice of Transvaal-sourced sandstone was a cause of ongoing discord and controversy.

Construction started around June 1910. The initial plan was to use considerable quantities of Balmoral sandstone for the facade of the Union Buildings. However, in the report of the Geological Survey for the year 1909, it is briefly mentioned that Dr Kynaston (the Director of the then Geological Survey), on behalf of the Department of Public Works, had commenced an investigation during the latter part of 1909 to research suitable building stones for the new Government offices and other public buildings. No reports were produced for 1909. This investigation was likely the result of the criticism voiced by Sir Herbert Baker during August 1909 regarding the choice of building stone. Dr Kynaston and Dr A.L. Hall continued with this investigation during 1910. Some of the samples were analysed in 1910 by the laboratory of the then Geological Survey and others by the Mechanical Laboratory of the Mines Department in Johannesburg.

The 1910 Annual Report of the Geological Survey was only published during June 1911, in which Dr Kynaston mentioned that Transvaal sandstones often contain pyrite, which may be concentrated locally to such an extent as

to be seriously detrimental to the stone on exposure to weathering. As the corner stones of the Union Buildings have already been laid during November of the previous year, it can be assumed that some progress had already been made with the construction of the ground floor by the time the results of the investigation were published in June 1911.

Fearing discolouration and possible decay, the stone was changed. For the walls of the first and second floors, Steenpan/Vlakpan/Klippan sandstone from the Free State was mostly used. This change of the sandstone source likely resulted in a surplus of large quantities of local Transvaal sandstone. The fact that fair amounts of Transvaal sandstone were used for constructing the numerous containing walls was likely an effort to get rid of the surplus stone.

The construction of the Union Buildings could be cited as an historical prominent case where early geological input and investigation could have avoided much uncertainty and unnecessary expenditure. Nowadays, several tests are available to evaluate the suitability of different types of dimension stones.

For more information contact:Rehan OppermanEconomic Geology and Geochemistry+27 (0)12 841 [email protected]

Cropped image of the Union Buildings. Sandstone

from different sources was used for constructing

the lower and upper sections of the walls (Photo

from https://repository.up.ac.za).

Lower retaining wall constructed

from rough cut stone obtained from

Meintjieskop itself and from site

excavations. The higher retaining

wall is constructed from neatly cut

sandstone, possibly from surplus

Transvaal sandstone. On the main

structure, a slight colour difference

in the sandstone is visible between

the ground floor and the first and

second floors (photo from http://

transformsa.co.za).

If you are not on our mailing list and you would like to receive a copy of GEOclips, please send an e-mail to:

Mahlako Mathabatha, Marketing, Communication & Stakeholder Relations [email protected]

Private Bag X112, Pretoria 0001, South Africa / 280 Pretoria Street, Silverton, Pretoria 0184, South Africa

Tel: +27 (0)12 841 1911 / Fax: +27 (0)12 841 1221 / www.geoscience.org.za

Merging maps for an emerging future

The Council for Geoscience Conference will bring together national and international scientists to discuss aspects of its new “integrated and multidisciplinary geoscience mapping programme 2018–2021”.

Within the broad geological mandate of the organisation, special emphasis will be placed on: geoscience for minerals and energy; geoscience for infrastructure and land use; geoscience for health, groundwater and the environment; geoscience innovation; geoscience diplomacy.

The technical organising committee received 84 abstracts in the above-mentioned subject areas that will be presented in two parallel sessions. The conference has ten invited national and international experts presenting on issues relevant to the conference subthemes. These keynote presenters are Dr Bob Thomas, Dr David Khoza, Dr Emmanuel Sakala, Dr Jeanine Engelbrecht, Mr Stephen Hine, Prof. Louis van Rooy, Prof. Laurence Robb, Prof. Patrick Vrancken, Prof. Richard Ernst and Prof. Ronald Cohen. With this annual conference, the CGS hopes to provide its stakeholders with insight into all the nationally funded research projects it is undertaking.

The conference is fully subscribed due to a much larger than expected flood of registrations and consequently registrations have been closed until additional resourcing can be arranged. The organising committee will hopefully open the online registrations again and will post any new information on the conference website. The website is available at http://geoscience.org.za/cgs/ and may be perused for more information such as the draft conference programme for all presentations and details regarding the specialisations of the keynote presenters.

8 inside: new manager to take the council for geoscience...

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