Tembang Geology

Tembang encompasses an extensive low-sulphidation epithermal system comprising northwest and northeast trending, gold-silver bearing quartz-sulphide veins hosted in Miocene intrusive volcanic and volcaniclastic rocks. Tembang is believed to be focused within a zone of dilation created by faulting associated with the Trans-Sumatra Fault Zone that parallels the Sumatran volcanic arc.  

Individual vein lodes have strike lengths of between 200 and 500m, however mineralised trends are observed to be greater than 1km.  Vein widths are typically less than 2m, however at Berenai vein lodes or complexes are greater than 5m and locally up to 10m. Gold-silver mineralisation is found associated with quartz-chalcedony veins, vein breccias and vein stockworks with a low sulphide content. The veins display typical epithermal characteristics including crustiform-colloform banding, silica pseudomorphs after bladed calcite, adularia, amethyst and bands of fine grained dark sulphides. 

The depth extent of the economic mineralisation outlined to date appears to be approximately 300 metres, however several high grade vein lodes have not been closed off at depth. As such, the potential for resource growth is considered to be high in that most known deposits remain open at depth, along with a pipeline of prospective near mine exploration targets.