Over the past two years there has been discussion among South African physicists about the possibility of establishing a deep underground physics laboratory to study, amongst others, double beta decay, geoneutrinos, reactor neutrinos and dark matter. As a step towards a full proposal for such a laboratory a number of smaller programmes are currently being performed to investigate feasibility of the Huguenot Tunnel in the Du Toitskloof Mountains near Paarl (Western Cape, South Africa) as a possible sight for the South African Underground Laboratory facility. The programme includes measurements of radon in air (using electret ion chambers and alpha spectroscopy), background gammaray measurements (inside/outside) the tunnel using scintillator (inorganic) detectors, cosmic ray measurements using organic scintillators and radiometric analyses of representative rock samples.
Wyngaardt, S. M., Newman, R. T., Lindsay, R., Buffler, A., De Meijer, R., Maleka, P., … Ndlovu, Z. (2015). Towards the South African Underground Laboratory (SAUL). In Physics Procedia (Vol. 61, pp. 586–590). Elsevier B.V. https://doi.org/10.1016/j.phpro.2014.12.056