The exploitability of pegmatite deposits in the lower Orange River area (Vioolsdrif - Henkries - Steinkopf)

Abstract

This study aims to investigate the exploitability of the pegmatite deposits in the lower Orange River area, situated between the settlements of Vioolsdrif, Henkries and Steinkopf in the Northern Province, in the light of current methods of financial analysis. A summary of the prevailing ore deposit model and a description of the geology are presented, and a financial analysis is undertaken taking into account the resources, current market conditions, and the legal requirements associated with a mining venture on the pegmatite bodies. The most acceptable ore deposit model for the formation of pegmatites currently presents the pegmatite body as the final stage of crystallization of a cooling magma (Cerny, 1998a). Recent studies suggest that the crystallization of the pegmatite occur at an unexpectedly fast rate by the working of undercooling, in which the rate of cooling exceeds the rate of crystallization (London, 2005). The pegmatites of the study area are mostly developed in granites of the Vioolsdrif Suite, in a post-orogenic tectonic setting and in many respects, fit well into the model of Ginsburg et al. (1979). Although resources are difficult to estimate, it can be said that individual pegmatite bodies in the study area host reserves of up to 50 Mt of pegmatite ore. The markets for feldspar, currently the primary commodity in pegmatites, show an increase in price and a positive outlook for the future. Legal requirements (licensing) are rigorous, under the new Act even more so than under the old, especially with regard to environmental issues. A financial analysis suggests that, although mining operations on pegmatite bodies are highly sensitive to changes in commodity prices, revenue and fuel-related expenses, they are feasible under the current market conditions. Zebrakop pegmatite is identified in this study as a potential target for the exploitation of a homogeneous pegmatite, coupled with the necessary development of bulk mining methods and a beneficiation plant.