Results and discussion
3.1. Clayey material mineralogical composition
Clay samples (eight) collected at different points of the main river in Mondeor-Johannesburg had mostly blackish colour. The X-ray fluorescence and diffraction analyses of these samples showed almost similar patterns among the samples which have many minerals in common (Tables 1 and 2). The compounds in abundance were silica and alumina which are main components of the minerals identified such as muscovite, kaolinite and quartz.
Selective representation of X-ray diffraction results focusing on clay minerals allowed us to establish the presence of three differ- ent minerals in our samples. Also, the clay-mica muscovite was found in all the samples implying a dominance of argillaceous type of samples. Kaolinite was found in half of the sample while only one sample contained goethite.