Abstract

The present study is necessitated as a result of the use of kaolinitic clay as raw material for cement by West African Portland Company (now called Lafarge-WAPCO) situated in southwestern Nigeria. The study area covered an extent of 6 acres and fall within Ajebo town near Abeokuta. XRF and XRD techniques were employed in the determination of the chemical composition and crystalline component respectively. Vertical electrical resistivity soundings (VES) were used to evaluate the clay thickness, reserve and in the design of the exploitable zone of the clay deposit. The combination of XRF and XRD results show that quartz, kaolinite and feldspar are the dominant minerals. The VES results show indication of 3 to 5 geoeletric layers which include: the top soil (0.5 - 1.4 m), lateritic clay (1.7 - 4.7 m), indurated clay (4.4 - 11.3 m), clay sand (9.3 - 18.3 m), and saturated clay (6.3 m and above). The exploitable zone which corresponds to the “indurated clay” pinches out towards the depression as observed from the geoelectric sections. Using an exploitable zone average thickness of 4.25 m andarea extent of 8790 m², the clay reserve estimate is 9.5 x 10⁴ tonnes. Surface mining techniques will be appropriate as the overburden thickness is shallow.

Key words: Geoelectric sections, reserve, overburden, indurated clay, cement.