On the verge of making an Impact at Silica Hill

THE INSIDE STORY: Impact Minerals decision earlier this year to focus on expanding the already established Resource at the Commonwealth gold-silver-zinc project has already started to pay off.

Impact Minerals (ASX: IPT) 100 per cent-owned Commonwealth project is located 100 kilometres north of Orange in New South Wales.

The Commonwealth project is already ahead of a number of its peer projects in that it has an established mineable gold equivalent resource and a one million ounce – plus exploration target.

Commonwealth has current Inferred gold-silver-copper-lead-zinc Resources of 720,000 tonnes at 4.5 grams per tonne gold equivalent (AuEq) containing 110,000 ounces AuEq, including 140,000 tonnes at 9.3g/t gold for 47,000 ounces AuEq.

Impact Minerals holds the 315 square kilometre project in high regard, and considers it to have the potential for small scale, early production.

Of late, Impact has received a highly-encouraging run of results from a reverse circulation (RC) and diamond drilling program it has been conducting at Commonwealth, to the point where it recently announced it was to be extended by about 25 per cent to follow up encouraging assay results achieved at the Silica Hill, Walls and Commonwealth prospects.

The drill program is testing a number of targets Impact had previously identified at four separate locations across the Commonwealth project.

These include the eponymous Commonwealth deposit, Silica Hill, the Walls- Welcome Jack Trend, and Doughnut.

A maiden drill hole at the Walls prospect, 1.2 kilometres east of Commonwealth identified a 20 metre thick zone (true width) of gold and silver mineralisation.

The Walls prospect lies at the southern end of the Welcome Jack Trend, which extends over a strike length of at least one kilometre and has not been previously drill tested.

Impact viewed the maiden drill result from Walls to be encouraging for the discovery of further high-grade gold-silver mineralisation, deeming it to indicate potential for near surface open pit resources at the dopiest.

However, it was drilling at the Silica Hill deposit where strong interest grew, as three new drill targets emerged from the identification of two important controls to the higher grade mineralisation in the Silica Hill-Commonwealth deposit when combined with assays from previous drill holes.

It was decided two of the targets would be immediately included into the current program with the third area likely to require a new drill permit from the NSW Department of Mines.

Studies completed by Impact indicated the possibility the high grade mineralisation at Silica Hill and Main Shaft may be linked at depth.

A gold-silver-in-soil anomaly extends in a NE direction from Main Shaft towards Silica Hill and widens in that direction, which remains open to the north and north-east.

Impact believes this to be further indication the two areas may be linked and further drilling at depth is required.

“The results showed a clear overlap in the nature and style of mineralisation, in particular silver, as well as the alteration minerals between the two prospects,” Impact Minerals managing director Dr Mike Jones told The Resources Roadhouse.

“Areas where the two styles of mineralisation connected became obvious priority target areas.”

The subsequent drilling at Silica Hill resulted in the discovery of a 75 metre thick zone of vein and disseminated sulphide mineralisation.

The mineralisation was encountered by Hole CMIPT043 from 99 metres to 174 metres down hole.

Impact released assays for the first 60m of the zone drilled by reverse circulation drilling.

The last 15m of the zone was diamond drilled with the company still awaiting assay results as the time of writing.

The assays revealed the mineralised zone to have an upper silver-rich and a lower gold-base metals rich part, containing a number of higher grade intercepts – mostly associated with the veins.

Assay included:
60m at 0.4 grams per tonne gold, 51g/t (1.6 ounces) silver, 0.2 per cent zinc and 0.1 per cent lead or 1.3g/t gold equivalent from 99m;

This included:
30m at 0.1 g/t gold and 77 g/t (2.5 ounces) silver, 0.2 per cent zinc and 0.1 per cent lead or 1.3g/t gold equivalent from 99m; and

10m at 2g/t gold, 38g/t silver (1.2 ounces), 0.4 per cent zinc and 0.2 per cent lead or 2.9g/t gold equivalent from 149m (to end of RC hole at 159m).

Six higher grade intercepts were encountered within these broad zones, which Impact considers, together with the diamond drill core, demonstrate the presence of numerous veins containing very high-grades of silver and probably other metals.

The upper silver-rich part of the zone also included intercepts of note including:
1m at 122g/t (4 ounces) silver and 0.2g/t gold from 108m;

1m at 146 /t silver (5 ounces) and 0.1 /t gold from 118m;

2m at 373g/t (12 ounces) silver, 0.2g/t gold, 1.8 per cent zinc and 0.9 per cent lead from 123m, including 1m at 525g/t (17 ounces) silver, 0.1g/t gold, 2.1 per cent zinc and 1.1 per cent lead from 124 m; and

1m at 0.1g/t gold and 337g/t (11 ounces) silver from 134m.

The lower part of the zone produced the first significant gold assays from the Silica Hill prospect with higher grade intercepts within a 10m thick zone including:

1m at 2.3g/t gold, 64g/t (2 ounces) silver, 1 per cent zinc and 1.1 per cent lead from 153m; and

1m at 6.4g/t gold and 18g/t silver (0.5 ounces) from 155m.

“There is little doubt this new discovery at Silica Hill is a very significant development for the Commonwealth project,” Jones said.

“It demonstrates that very thick widths and also high-grades of mineralisation exist outside the Commonwealth deposit and that we have been able to achieve an intercept like this very early on in our drilling at the prospect is extremely encouraging.

“Having previously encountered very high-grade intercepts of massive sulphide from the northern end of the Commonwealth deposit itself, these latest results should allow us to increase in the project’s resource.

“It should come as no surprise that we are now very keen to test this new discovery along trend and at depth where potentially it may even connect to the underlying massive sulphide.”

Impact has interpreted the new newly-discovered zone connects to previous thick intercepts in two drill holes drilled during previous campaigns at Silica Hill.

CMIPT011 returned:
20m at 44g/t silver from 122m ending in mineralisation; and

CMIPT026 which returned:
39m at 0.3g/t gold and 16g/t (half an ounce) silver (0.6g/t gold equivalent) from 5m.

According to Impact, there has now been significant silver-gold mineralisation defined by drilling over an area of 200m by 100m down to 200 metres below surface.

The mineralisation is open in all directions, including up-dip towards surface.

Impact has now moved the diamond drilling rig with the intention of re-entering hole CMIPT011. 

This hole has also returned significant mineralisation over a 50m width with assays pending.

Interpretation of previous results has determined this hole to have intersected the top of the mineralised intercept encountered in Hole CMIPT043.

Impact is hopeful that deepening the hole with diamond core will allow the company to glean further insights into the trend and nature of the newly discovered mineralisation.

Impact Minerals (ASX: IPT)
…The short story

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