The
Otago Goldfield has produced approximately 8 million ounces of alluvial gold and
over 2.5 million ounces of hard rock gold and is currently home to
New
Zealand's largest producing gold mine. In the
eyes of explorers this production history makes the goldfield a good place to
explore.

Modern exploration in
the Otago Goldfield commenced in the late 1970s with the exploration for
tungsten. However, a rapid rise of the gold price in the early 1980s saw the
focus shift to the exploration for gold which lead to the discovery of the
Macraes Gold Project in 1984, which since it came into production in 1990 has
been New
Zealand's largest producing gold mine. With the
exception of the Macraes Gold Project, exploration continued in the Otago
Goldfield for a further 20 years without further success.

In
2006, Glass Earth (NZ) Limited (Glass Earth) reviewed all the exploration
technologies applied to the Otago region and available geological data,
including the 1996 OceanaGold Helicopter Electro-Magnetic (HEM) data, and
concluded that combined magnetics and HEM were able to delineate the Hyde
Macraes Shear Zone (HMSZ) which hosts the Macraes Gold Project. Unlike previous
explorers who explored the Otago region in a piecemeal manner, Glass Earth opted
to collect a new, region-wide dataset which could be integrated with all
previous collected geological information to come up with new exploration
concepts and targets. As part of this process, Glass Earth applied in mid 2006
for New Zealand's largest on-shore gold Prospecting Permit, PP39-322 which was
subsequently granted in November 2006. In mid January 2007, Glass Earth
commenced acquisition of approximately 50 000 line kilometres of HEM data,
making the Otago regional aerial geophysical survey (survey) the largest aerial
geophysical survey ever undertaken in New Zealand.

This
paper will report on the progress of the Otago Regional aerial geophysical
survey and outline some of the preliminary findings from what is still a work in
progress.