Victorian-focused explorer Navarre Minerals (ASX: NML) has reported “highly encouraging” gold intercepts from reconnaissance aircore drilling at its wholly-owned St Arnaud gold project, 240km northwest of Melbourne.
First results from the program on the New Bendigo Line have shown strong gold mineralisation from wide-spaced drilling across a target area which forms one of the three main trends of the historic St Arnaud goldfield.
Assays include a standout 20m broad intercept grading 1.8 grams per tonne gold located 180m north of the historic New Bendigo mine, which is the second largest mine within the goldfield.
Within that broad intersection were numerous high-grade gold intervals of 1m at 9.2g/t, 1m at 6.9g/t and 1m at 5.5g/t.
Other notable drill results were 4m at 3g/t gold from 6m; and 3m at 2.2g/t gold from 49m.
Navarre managing director Ian Holland was pleased with the positive assays.
“St Arnaud is the second largest hard rock goldfield in Victoria’s Stawell Geological
Zone which, until now, has missed out on [the State’s] gold resurgence,” he said.
“We are currently drilling in the shadow of St Arnaud’s second largest historical mine and we have been encouraged by the tenor and widths of near-surface gold mineralisation intersected to date.”
Along with other high-grade intercepts, Navarre said the result confirms a strong potential to discover significant economic gold mineralisation beneath the goldfields’ shallow historical workings.
The aircore program is testing the potential for economic levels of gold mineralisation around historic shallow workings, in conjunction with a deeper 2,000m diamond drilling program to follow-up rich legacy drill hits, including 1m at 1,174g/t gold beneath New Bendigo.
This aircore program marks Navarre’s first drill testing beneath the shallow gold workings of recently granted exploration licence EL 6819 which includes the gold-bearing New Bendigo (Bristol), New Chum and Nelson lines of reef.
Drill testing has already covered 4,000m which Mr Holland said would likely be extended beyond 5,000m given the positive results to date.
St Arnaud history
The permit covers most of the historical mines of St Arnaud, which produced 400,000 ounces of gold between 1855 and 1916.
The prolific Nelson line hosts the deep Lord Nelson mine, which was the region’s largest producer – churning out more than 300,000oz of gold.
Alluvial gold was first discovered at St Arnaud in 1855 and quickly traced to its source in outcropping quartz reefs.
Just five years later, around 47 hard rock mines were in operation across the region.
The Nelson line produced the most gold and was worked over a strike length of approximately 5km to a maximum depth of 685m.
Lord Nelson was the only mine to produce gold from sulphide ores below a depth of 200m.
Most other mines closed once they reached the water table because the technology was not available to economically treat the sulphide ores in addition to the added cost of pumping mine water.
In 2018, Navarre’s maiden reconnaissance drilling program demonstrated the potential for economic mineralisation of the St Arnaud goldfield to extend under shallow Murray Basin cover more than 5km beyond the limits of the historic workings.
The mineralisation remains open along strike, with the best gold result being 4m at 6.6g/t gold from 48m and the best silver result being 1m at 67.4g/t silver from 50m.