A total of 36 reconnaissance aircore holes comprising 1,423 metres were drilled in the phase one and phase two programs in the Southern Area with the aim of finding similar mineralised systems as nearby Evolution Mining Ltd’s (ASX:EVN) Cowal and CMOC’s (SHA:603993) Northparkes mines.
Rimfire managing director Craig Riley said: “The results from the phase one and phase two drilling programs over the Northern and Southern Areas support the Rimfire interpretation that the basement rocks are older Ordovician rocks that also host the nearby significant Northparkes (copper/gold) and Cowal (gold) mines.”
However, testing indicates that it is likely to be from stage II volcanism rather than the stage III and IV volcanism associated with mineralisation at Cowal and Northparkes.
Drilling at the Northern Gold prospect was designed to test the bedrock beneath a 400 metre long by 80 metre wide zone of historical mine pits.
The phase one RC drilling consisted of two holes totalling 165.5 metres and generated anomalous gold (0.15 parts per million), copper (0.17%), lead (120 parts per million) and zinc (0.13%) although it did not intersect high copper or gold grades.
These results are supportive of the Intrusion Related Gold System (IRGS) model for mineralisation in the area.
The surface gold remains unexplained by the limited drilling to date and an aircore drilling program is the next step in understanding and locating the source of historical gold from this prospect.
The company believes the known footprint of Northern Gold historical gold workings supports the potential for a significant mineralised system, which could be either an independent mining operation or an incremental additional source of supply feed to any Sorpresa development.
Rimefire project location
Phase three program
The focus of the planned phase three drilling program will be the Northern Gold prospect historical gold workings that were partially tested in phase one, as well as the Transit prospect, around 3 kilometres to the east of Sorpresa, where in 2017 Rimfire obtained promising intersections of 20 metres at 1.11 g/t gold from 48 metre depth.
Riley said: “The focus of work for phase three drilling will now transition to the Northern Gold and Transit prospects which both retain strong potential for economic gold mineralisation that could be independent significant discoveries or be accretive projects to any development of the Sorpresa Resource.”
The focus of the next phase of work at Transit will be to better understand the geological structural setting that is thought to control zones of mineralisation and to test initially for further zones of shallow higher grade mineralisation that may support Rimfire’s dual strategy of monetisation of Sorpresa and ongoing exploration towards discovery of a mineralised system of economic significance.
The company is currently working to obtain the necessary NSW Government drilling approvals and local land holder access agreements for phase three drilling, however, expects the Coronavirus to influence the scheduling of company activities in the short term.