The holes — seven from within underground mine workings and six drilled from surface — are aimed at increasing confidence in the deposit ahead of an updated resource estimate due for release later this month.

The final set of results from the drilling program included 9.6g/t of gold and 34.9g/t of silver over 21.4m, and 11.5g/t of gold and 48.6g/t of silver over 12.9m.

"These latest holes continue to re-affirm the new geological model developed by Bluestone, where broad widths of high-grade mineralisation occur due to multiple quartz-adularia veins converging at depth, possibly representing a feeder structure," the company said.

The company acquired the advanced underground project from Goldcorp in May last year for US$35 million plus shares.

One hole encountered new high-grade veins discovered through recent underground channel sampling in the South Ramp access tunnel and will be included in the new resource estimate, part of a feasibility study due by the end of this year.

"Our understanding of the geologic potential within and immediately adjacent to the current deposit, has been significantly enhanced through the drilling and sampling programs," said Bluestone CEO Darren Klinck.

Based on a preliminary economic assessment filed with regulators last year, Bluestone expects to invest $171 million to bring the underground mine into production.

The operation is expected to produce 138,000 ounces per annum of gold during its first four years of operations at an all-in sustaining cost of $490 per ounce.

The deposit is estimated to contain a resource of 1.2 million ounces of gold with an average ore grade of 10.2g/t of gold.