Shares in North River Resources (LON:NRRP) shot up almost 18% after it said current drilling at its flagship Namib lead-zinc project has increased its confidence in the mineral resource at the Namibia property.
Resource expansion drilling is now underway but the group has drilled out 4,828 metres, in 66 holes, since the summer of 2014, when the last JORC estimate was published.
That showed the total resource had grown by 36% to 1.25mln tonnes with zinc and lead grades 6.5% and 2.5% - a rise of 13% and 4% respectively.
Drilling since has focused mainly on targeting both new extensions of known mineralised shoots, as well as infill drilling to potentially convert inferred into the higher confidence indicated category.
The work has mainly been on the top half of the North Orebody and also below the historic South Mine, which is around 200m below surface.
Significant intercepts have included 7.3 metres at 14.9% Zinc, 3.2% lead and 4.5m at 9.3% Zinc, 13.6% lead.
Chief executive of North River James Beams said: "I am encouraged that the results of the drilling have confirmed previous drilling and I am very pleased to share the high grade drill results from the Southern orebody.
"I look forward to providing regular updates on the resource expansion drilling campaign and other pre-construction work streams over the coming months".
Earlier this month, shares surged around 27% as North River unveiled a key step toward a mining licence for its flagship Namib lead-zinc project, receiving from the ministry of mines and energy what's called a "notice of preparedness" to grant the document.
Shares today gained 17.86% to 0.0825p.