Pantoro Ltd (ASX:PNR) (FRA:RKN) is confident that the historic Mainfield system at Norseman Gold Project in Western Australia will extend mine life, after receiving high-grade drilling results up to 5.7 metres at 35.85 gold from an initial drilling program.
The results suggest that high-grade mineral resources and ore reserves from Mainfield will be included in future optimisations of the phase one mine plan and that Mainfield ore bodies will be accelerated into phase one mining.
In the past, the system produced around three million ounces with grades of more than 11 g/t.
Within the 5.7-metre intersection was 1.4 metres at 141.57 g/t while other notable results include 1-metre at 23.5 g/t, 0.45 metres at 21.9 g/t, 2 metres at 20.61 g/t, 2 metres at 15.87 g/t, 6 metres at 14.94 g/t and 1-metre at 10.3 g/t.
High grades “consistent theme”
Speaking to the results, PNR managing director Paul Cmrlec said: “These results continue to demonstrate the very high grades, which are a consistent theme at Norseman.
“The iconic Mainfield was not considered in the phase one feasibility, and addition of mineral resources and ore reserves from this area are expected to increase mine life and head grades.
“Ore within Mainfield can be highly nuggety, with a mix of very high grade and lower grade holes as we have seen in this first campaign eventuating in outstanding production outcomes historically.
“Few if any goldfields in Western Australia have produced so many ounces of gold at the very high grades encountered in Mainfield, and this drilling confirms that there is plenty more to come.
“Proving up high-grade ounces in Mainfield was an objective set by Pantoro at the time of acquisition of the project and our work programs are on track to significantly enhance the outcomes of the phase one feasibility study.”
Drilling was focused on unmined virgin blocks outside of the existing remnant mineral resources at Mainfield.
The existing underground mineral resource at Mainfield is 1.27 million tonnes at 13.1 g/t gold for 540,000 ounces, with only 44,000 ounces included in Pantoro’s phase one mine plan per the DFS announced in October 2020.
Reserve definition
Pantoro is utilising the current results in conjunction with historic drilling and face sampling results to generate internal planning models and guide the areas being drilled to indicated mineral resource status in the near term.
Areas confirmed as ore reserve target areas include:
- Three large unmined blocks within the Crown Reef;
- Butterfly area where extensions south of the historic limit of mining confirmed high grade results; and
- St Patricks open pit and underground extensions.
The areas of focus can be readily accessed from existing decline development at Viking and Bullen and the planned open pit at St Pats.
Between two and four drill rigs scheduled to be operating within the Mainfield areas throughout the coming financial year.
Drilling is underway from within the town boundary at Crown South, which is considered to have excellent potential for definition of large panels of previously unmined ore and is a priority target.
History and location
The Norseman Gold Project is in the Eastern Goldfields of Western Australia, at the southern end of the highly productive Norseman-Wiluna greenstone belt.
Discovered in 1894, the Mainfield Mining Centre was the primary ore source for historic operations and is adjacent to the town of Norseman.
The 5-kilometre-long Mainfield reef system was continuously mined for over a century from 1894, with the field acquired and developed on a large scale by WMC in 1936.
The north-south striking Crown and Mararoa Reefs produced the majority of the historically mined gold, however a cross linking structure named Bullen was only initially mined in 1991 and produced approximately 500,000 ounces.