f AN INVESTIGATION OF THE CONDITIONS AROUND A REHABILITATED GOLD MINE IN MONARCH AREA OF FRANCISTOWN, BOTSWANA

Mining in Monarch area exploited lenticular gold bearing quartz veins up to 400m long and 2m thick. These veins were emplaced along shears within a complex tectonic contact zone between the Francistown Tonalities and the Penhalonga Formation. The shears were localised by inclusions of altered schist within the tonalite. The shears extend some 1500m along a northerly trending strike, dipping steeply to the west. Subsidiary shears trending north-north-east and northwest are also mineralised and the highest grades are found where these intersect with the main zone. The wall-rock hosting the veins also has impregnations of carbonate and sulphide, and typically contains fine-grained biotite (or stilpnomelane) which imparts a brownish hue to the altered zones.