Tenth and final report on EL 9742 Border Diamonds for the period 16 June 2001 to 15 June 2011

Abstract

An ovoid photo-geological feature on EL 9742 does not appear to be a simple drainage or regolith landform and may outline a collapsed kimberlite or carbonatiite volcanic vent. If so, it would be highly prospective for diamonds. Within the ovoid feature there are undisturbed outcrops of Jurassic DeSouza Sandstone, and so the ovoid feature must be even older. No units beneath the De Souza Sandstone, such as basement, have been identified within the ovoid feature; the nearest exposed basement (granite) is 4 km west. Two previous heavy mineral samples within the ovoid feature returned garnet: one had strong kimberlitic affinities. Previous work also revealed a number of gold anomalies within EL 9742, including an ironstone rockchip that returned 24 g/t Au (putative basement). The location from where this ironstone was collected has never been re-identified, but widespread elevated Au values in soil samples suggest high gold prospectivity. Gold anomalism was found in a variety of regolith environments, including gravel sheetwash adjacent to outcrop and sandy sheetwash distal from outcrop. Followup detailed soil sampling of these previous soil anomalies has been completed and returned no elevated gold. The only remaining work is to drill test part of the ovoid feature to check whether it is a kimberlite. In the 10th year of tenure no work was undertaken. Extreme wet conditions washed away the access road along the boundary fence and hence access was not possible. It was decided to surrender the tenement.