KINGSROSE Mining has significantly improved performance at its Talang Santo gold and silver mine largely as a result of implementation of a plan to minimise the impact of water on production horizons. The improvement was typified by record ore production during the December quarter.
The dewatering plan included commissioning of a 200kw multi-stage pump on the 4 Level, which resulted in a significant lift in production from the mine in November and December. Production from stoping was 7960 tonnes @ 12.2 grams/tonne (g/t) gold and 30.1 g/t silver. A total of 21,341 ore tonnes were mined at 9.4 g/t gold for the period, representing an increase of 62% over the September quarter, with the bulk of the tonnage mined from development drives.
Surface infrastructure at Kingsrose Mining’s Talang Santo mine in southern Sumatra.
Mining activities during the quarter were focused on sublevel and stope development on the 4 Level. Significant advance rates were achieved opening up a large proportion of the mineable area on the 4 Level with the bulk of the work areas now dry. A total of 2017 metres of development advance was achieved during the quarter, including 1719 metres of operating development, which represents an increase of 89% over the September quarter.
The development of the external shaft to the 5 Level was suspended during the quarter due to the intersection of a significant water-bearing fault structure. A grouting program has been designed to seal and minimise the water ingress to both the Splay vein and the external shaft. Kingsrose expected the program to commence during the March quarter with development on the external shaft to recommence early in the June quarter.
Plant throughput for the December quarter was 21,612 dry tonnes at a head grade of 9.3 g/t gold and 24 g/t silver. Recoveries of gold and silver were 96% and 86% respectively. Lower silver recovery was attributed to a planned trial to reduce the concentration of cyanide in the leach circuit. The trial resulted in significant cost savings in re-agents, with the processing plant achieving a record milling cost per tonne during the December quarter.
Gold production for the quarter increased 55% on the previous quarter to 6212 ounces and silver production was up 43% to 14,888 ounces. All-in sustaining costs averaged US$963 per ounce which was a record quarterly low for Talang Santo.
Ongoing drilling at Talang Toha identified a broad mineralized zone while drilling at Mitra Jaya intersected host lithologies to both the Way Linggo and Talang Santo deposits.