Sun Metals said Thursday the latest six holes drilled on the 421 zone extended the known plunge length to more than 160m, which remains open to the north and south. The drill results continued to show the continuity of the system and the prevalent skarn alteration that surrounds the copper-gold mineralisation indicated drilling was on the correct trajectory to find the mineralising source, the company said.

Highlights from the most recent drilling included 45.55m grading 1.44% copper, 1.18 grams per tonne gold and 27g/t silver for 2.44% copper-equivalent; 24.85m grading 3.13% copper, 4.85g/t gold and 93.5g/t silver for 7.12% Cu-eq; and 15.9m at 2.38% copper, 2.68g/t gold and 66.6g/t silver for 4.71% Cu-eq.

"The alteration encountered in 2019 drilling to date confirms our belief that we are still distant from the heart of the system, which indicates to us there is significant, highly prospective exploration ground to the north with the opportunity to discover more of the high-grade copper-gold mineralisation that we are seeing in the 421 zone," said VP for exploration Ian Neill.

"We also expect to see increased consistency in grades from hole to hole as we track the mineralising fluids to their source."

CEO Steve Robertson said the team expected the sulphide replacement of the skarn alteration to be more complete closer to the high-energy heat source, theoretically resulting in even higher grade material.

"This is what drives us to continue our focus on the trend to the north. We are excited that our team will continue exploration over the coming winter months as we learn more about this impressive high-grade system."

Since drilling started in May, the company has completed 8,860m in 19 drill holes.

Sun Metals said last month it would add a third drill to the ongoing programme and it was preparing an all-season camp to enable drilling to continue through the winter months.

The third drill will accelerate the campaign and will be used to test the continuation of the 421 zone up-plunge to the south.