Economic gold mineralisation was
discovered at Round Hill by Homestake NZ Limited in 1984 and was subsequently
put into production by Macraes Mining Company Limited (MMCL) in 1990. The total
mineral resource in 1990 was estimated at 41.4 Mt @ 1.42 glt at a
0.7g/t cut off, for 1.8 Moz of gold. Since project start up the mill has
been upgraded twice to increase throughput and reached its current capacity of
3.2 Mtpa. At 31 December 1996, a total of 16.2 Mt of ore at average grade of
1.73 g/t has been
excavated, yielding 655,000 oz of gold. MMCL began exploration along the Hyde
Macraes Shear Zone in 1994. Since 1994, exploration has been successful with the
discovery of over 3.5 Moz of gold. The resource now stands at 110 Mt @ 1.46
g/t gold for 5.1 Moz. This success has led to a
planned expansion of the processing capacity to 9 Mtpa with the building of a
new 6 Mtpa processing plant.