The new target, called Rudnica North, was initially identified by soil sampling and is located 500 metres north of Tethyan's previous drilling at its flagship Rudnica copper-gold porphyry project in southwestern Serbia.
Rudnica North displays a similar geophysical and geochemical signature to Rudnica, suggesting that the two areas may be linked at depth., Tethyan said.
The announcement came as part of the publication of the results of channel sampling at Rudnica.
Highlights include hole RCH002: 70 metres (m) @ 0.27 grams per tonne (g/t) gold, from 0 m to 70 m; hole RCH003: 71 m @ 0.43 g/t gold, from 0 m to 71 m; hole RCH015: 40m @ 0.21 g/t gold, from 15 to 55 m; hole RCH016: 30m @ 0.24 g/t gold, from 0 to 30 m, and hole RCH017: 10m @ 0.26 g/t gold, from 0 to 10 m.
The first two holes listed above are from Rudnica; the others from Rudnica North.
At Rudnica, the channel samples (RCH002 and RCH003) demonstrate a continuation of the near surface, gold-bearing leached zone 50m to the south of the current limits of drilling. This information will be used to guide drill program planning for the 2018 season and further emphasises the exploration potential at Rudnica, Tethyan said.
At Rudnica North the channel samples were collected from argillic and advanced argillic altered andesite and andesitic volcaniclastic rocks that crop out over an area of 160 by up to 80 metres; the outcrop is limited to road cuts and small, historic exploration pits.
The peripheries of this anomalous area were drilled historically (2011 to 2013) by a private Serbian company on a wide spacing for lead-zinc exploration purposes to between 250 and 370 metres depth. Gold and copper were not routinely assayed or reported during this historic exploration; however, one hole (RB-20) returned 44m at 0.4 g/t gold from surface.
Tethyan said it has not verified the historic drill data and the data should not be relied upon. Hole RB-20 is located 300 metres south of these recent channel samples and indicates that the mineralised zone may extend to an overall strike length of 600 metres.
Copper values returned by the channel samples were generally low, yet anomalous, typically in the range of 0.03 – 0.1 % copper; however, this was to be expected as Tethyan's drilling results indicated there is good evidence of oxidation and leaching of copper mineralisation at shallow depths, and re-precipitation of copper as a high-grade supergene enrichment blanket.
At Rudnica the supergene zone is typically 20 - 40 metres thick, commencing at roughly 80 – 120 metres below surface and grading around 1.0 - 1.5 % copper and 0.2 – 0.4 g/t gold, below which drilling intersected primary sulphide copper and gold mineralization.
Tethyan said gold mineralisation remains largely in-situ during the leaching process, and it believes it is this copper-leached, auriferous zone that it is seeing in the channel results at Rudnica North.
"The Rudnica North target is inferred to represent a leached, gold-bearing, copper-poor lithocap overlying a concealed copper-gold porphyry centre,” said Fabian Baker, Tethyan's president and chief executive officer.
“The same alteration and metal zonation is observed at Rudnica and the two zones may be linked at depth over a total strike length of more than one kilometre, as indicated by the results of the Titan DCIP geophysical survey we completed in late-2017. The Rudnica North porphyry is inferred to lie in a down-thrown fault block relative to Rudnica, therefore copper-gold porphyry mineralisation is anticipated to occur at depth, underlying the auriferous lithocap.
“The potential for supergene copper enrichment at the base of the lithocap has not been tested, but has been proven at Rudnica and Rudnica North appears at this early stage to be an analogous system," he added.
Fabian revealed that rock-chip, channel sampling and mapping is continuing to identify areas of untested alteration east and north of Rudnica.
“Our exploration team is continually building on the understanding and interpretation of the Suva Ruda license area and producing additional near-term exploration targets," Fabian said.