The National Core Library at Donkerhoek, managed by the Council for Geoscience, contains a large collection of borehole cores and cuttings from South African geological strata collected over a period of more than 25 years. Continued collection of borehole material aims to make the collection as representative as possible of all the major lithostratigraphic units in the country.
- To provide material for research on the petrography, geochemistry, stratigraphy and genesis of sedimentary, igneous and metamorphic rock units undertaken in connection with exploration for economic minerals, as well as engineering-geological and environmental projects;
- To serve as type sections or reference sections for poorly exposed lithostratigraphic units.
- Interested parties, including research institutions, mining companies, urban planners, etc. are hereby invited to make use of the borehole core, cuttings and logs housed at the NCL. Donations of borehole core and cuttings will be welcomed.
Fig. 1: View of the National Core Library building at Donkerhoek.
Fig. 2: Roadmap to the National Core Library.
Follow the N4 (Witbank) freeway. Carry on up to the Boschkop/Donkerhoek offramp. At the stop street, turn left and at the next T-junction, turn right into the Old Bronkorstspruit Road (R104). Carry on for about 1 Km up to the Renosterfontein signboard and turn right. Carry on for about 2 Km and turn right at the Mooiplaats signboard. The entrance to the Core Library is about 200 metres down this road on the right.
Alternatively, out of Siverton, follow Pretoria Road eastwards toward Bronkhorstspruit for about 30 Km, up to the Renosterfontein signboard and turn right. Carry on for about 2 Km and turn right at the Mooiplaats signboard. The entrance to the Core Library is about 200 metres down this road on the right.
Follow the N1 (Pietersburg) freeway and take the N4 (Witbank) offramp. Follow the signs towards the N4. Take care not to turn too soon, which will lead you into Pretoria. From here follow the N4 (Witbank) freeway. Carry on up to the Boschkop/Donkerhoek offramp. At the stop street, turn left and at the next T-junction, turn right into the Old Bronkorstspruit Road (R104). Carry on for about 1 Km up to the Renosterfontein signboard and turn right. Carry on for about 2 Km and turn right at the Mooiplaats signboard. The entrance to the Core Library is about 200 metres down this road on the right.
In order to render an efficient service to the public and to continue with an active core collecting programme, a modern coreshed was built at Donkerhoek, 20 km east of the Council's premises at Silverton. The facility has recently been expanded by the addition of a second coreshed and the current capacity is in access of 1 000 km of core.
Fig. 3: The modern storage racks that host the core at the NCL
The new coreshed has the capacity to accommodate more than 1 000 km of core. The present collection comprises the cores and cuttings of approximately 1 500 boreholes with a cumulative depth of 420 km, 210 km of which consists of core and the rest of cuttings.
Most of the core and cuttings were acquired during SOEKOR'S oil exploration programme and the Council's stratigraphic drilling programme. The rest was donated by mining companies.
Although most of the boreholes are relatively shallow, six boreholes are deeper than 1000 m. This includes one of the deepest boreholes ever drilled in South Africa, namely borehole TF1/72 in the North West Province which penetrated 4573,76 m of strata belonging to the Transvaal, Ventersdorp and Witwatersrand Supergroups, and the deepest cutting borehole, namely borehole SC3/67 in the Aberdeen District with a depth of 5556 m.
An electronic database, containing borehole number, locality, name of institution that drilled the borehole, stratigraphy, depth and position of the core at the coreshed, etc. facilitates easy access to any core or part thereof. Detailed logs of most of the boreholes are also kept, together with all additional work that has been carried out, including chemical analyses. Limited sampling of the core is allowed, in order to avoid depletion.
Inspection of Borehole Core
Inspection and sampling of core is subject to a fee to defray the cost of storage, maintenance and handling of the borehole collection. A written, fax, phone or E-mail enquiry should be made in advance to ascertain whether the specified borehole material is available. Please provide all available information on the required borehole as this will facilitate the search for computer information regarding the locality of the borehole in the NCL and the log. Hereafter a fax must be sent to confirm the intention to view the core and agreement on the fees involved. This confirmation must preferably reach the Council 1 to 2 weeks prior to the intended visit.
The Council for Geoscience does not charge Value Added Tax
- Viewing of Core
First 10 trays or part thereof (per borehole) R 450,00
Each tray thereafter R 15.00
- Copy of logs
R 80,00/log plus copying costs.
- A4 copy: black-and-white R0.50, colour R7.50
- A3 copy: black-and-white R1.00, colour R15.00
- A0 copy: black-and-white or colour R375.00 - copy supplied as PDF file on CD
R 100.00/sample (samples are one quarter of core and 50mm long)