St Arnaud Gold Project

Location

Western Victoria, Australia

Geological Province

Bendigo-Stawell Zone, Lachlan Fold Belt

Commodity

Gold, Silver

Ground holding

Exploration Licence 006556 (479 km2) & Exploration Licence Application 006819 (8km2)

Status

Navarre Minerals 100%

Project Summary

The St Arnaud Gold Project is located to the west of Bendigo and includes the historical 0.4Moz St Arnaud Goldfield. In line with the Company’s strategy of targeting gold mineralisation near multi-million ounce gold mines, the geological team assessed the available data for the historical St Arnaud Goldfield and highlighted considerable potential for a Fosterville-style high-grade gold mineralisation system containing multiple structural targets beneath shallow Murray Basin cover and in the exposed East Field prospect .

The gold mining history in St Arnaud dates back to 1855 when alluvial gold was first discovered and was quickly traced to its source in outcropping quartz reefs.  By 1860, 47 hard rock mines were in operation.  From 1855 to 1916, approximately 400,000ozs of gold were produced at a recovered grade of over 15 grams per tonne of gold from the hard rock mines.

The St Arnaud Goldfield comprises several lines of reefs which were worked to the edge of the Murray Basin cover.  These reef trends are known as the West Field, New Bendigo (Bristol), Nelson (including New Chum line) and East Field (Figure 1).

The Nelson line produced the most gold and was worked over a strike length of 3.2 kilometres to a maximum depth of 685 metres in the goldfields deepest mine, the Lord Nelson Mine.  The Lord Nelson Mine was the only mine to produce gold from sulphide ores below a depth of 120m with records showing a total of 323,000 recovered ounces (80% of total goldfield production).  Most other mines closed on reaching 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.

The Lord Nelson Mine demonstrates the prospectivity of the area in terms of vertical continuity of auriferous reef systems.  Ten steep west dipping auriferous quartz reefs of up to 7.5m width were worked between 1864 and 1916.  Historically, silver was a common occurrence with gold mineralisation in the St Arnaud Goldfield.

Modern exploration in the region started back in the 1970’s with shallow RAB drilling that returned anomalous gold-in-quartz within the range of 0.1 – 1.8 g/t Au. In 2008 Rex Minerals (ASX:RXM) reported bonanza style grades including 1m @ 1,174g/t gold from drilling beneath the New Bendigo Line (see Figure 2).

The Company’s exploration focus has been on understanding the geological controls on gold mineralisation in the exposed basement areas, tracing these mineralised reef systems along strike from historical workings and under shallow cover and then drill testing.

First-pass reconnaissance drilling on several key target areas has been completed following a program of geological mapping and / or re-processing of geophysical surveys (see Figures 1, 3, 4 & 5).

The drilling has delivered multiple significant intersections of gold and silver mineralisation successfully demonstrating the potential for economic mineralisation to exist under cover more than 5 kilometres beyond the limits of the historic workings of the St Arnaud Goldfield (Figure 1). This mineralisation remains open along strike and at depth and will be the focus of follow-up drilling.  The Company considers this an outstanding result given the early stage of greenfields exploration (wide-spaced reconnaissance drilling) and targeting through Murray Basin cover.

Highlight results from reconnaissance drilling through the Murray Basin cover include (See NML ASX release of 30 July 2018 & Figure 1):

  • 1m @ 67.4 g/t Ag from 50m down hole (SAC055)
  • 4m @ 6.6 g/t Au from 48m down hole (SAC022)
  • 1m @ 1.3 g/t Au from within a broader zone of 2m @ 0.8 g/t Au from 67m down hole (SAC024)

First-pass drilling was also recently completed on the East Field prospect where multiple encouraging gold and silver intersections within a broad arsenic halo were returned that exhibit strong geometrical similarities to the Swan and Eagle zones at the Fosterville Gold Mine.  The best gold result was returned was 6m @ 2.5 g/t Au from 80m (SAC098), including 1m @ 5.4 g/t Au within a broader interval of 25m @ 0.9 g/t Au starting from 63m.  The best silver result was 1m @ 81.0 g/t Ag from 81m (SAC082) within a broader interval of 8m @ 19.8 g/t Ag.

Importantly, all these drill intercepts were recorded in the oxide zone and remain open at depth.  The Company is planning for a deeper, follow-up drilling program targeting the fresh basement rocks beneath the oxide zone.

Figure 1: St Arnaud Gold Project map showing historic gold production, interpreted mineralised trends and significant Navarre drill intercepts (see ASX releases of 30 July 2018 & 5 February 2019).

Figure 2: Diamond core photograph of visible gold intersected in drill hole STDD-004 (1m @ 1,174 g/t Au) (Source: Rex Minerals Limited ASX release 16 April 2008).

Figure 3: Geological mapping of exposed gossanous reefs in the East Field prospect of the St Arnaud Gold Project.

Figure 4: AC drilling on exposed quartz reef in the East Field prospect, December 2018.

Figure 5: Gossanous rock chip from the East Field prospect.