Overview

Otago Region

The Otago Region has produced over 8 Million oz of placer (alluvial) gold since 1861 and hosts the mesothermal Macraes Gold Mine (OceanaGold Limited).

During 2007 Glass Earth collected new data using an advanced airborne mapping technology. The NZ$4M survey was flown over 53,000 line km, and took 7 months.
This data along with a significant new regional geochemical database, has provided completely new insights into the prospectivity of the region.

Target concepts incorporated into exploration programmes are addressing:
  1. Large tonnage/ounce resource in relation to unoxidised shear-related mineralisation
  2. Small, multiple, high grade, oxidised ore deposits

Conceptual modelling, combined with hard rock geochemical data, has highlighted that in many cases low angle shear related mineralisation is overprinted by small multiple high grade quartz veins host to coarse gold. These shallow high grade oxide ore systems are being examined to determine their potential to contribute to hard rock gold production via a mobile crushing and gravity separation plant.

Historical drilling, trenching and rock chip sampling and limited underground workings show potential for the recovery of this high grade mineralisation by gravity separation. Further prospects, including Ophir and Sparrowhawk, present opportunities to go directly to mining these shallow high grade oxide ores, and could provide sufficient gold resources to support production from a mobile plant.