Midnight Sun Mining Corp (TSX-V:MMA, OTCQB:MDNGF) said on Wednesday its ongoing drilling at the Dumbwa copper deposit in Zambia continues to define broad zones of near-surface copper mineralisation, including multiple high-grade intercepts, as it advances one of its largest exploration programs to date.
The Dumbwa deposit, part of the company’s Solwezi project in northwestern Zambia, sits in the Domes Region near First Quantum’s Kansanshi mine and Barrick’s Lumwana operation.
Midnight Sun said drilling has now exceeded 200 holes for more than 42,000 metres, confirming continuous copper sulphide mineralisation over a 5.3-kilometre strike length, with assays returned for roughly the first 4 kilometres.
Among the reported results, hole DBW-25-099R returned 93 metres grading 0.4% copper from 152 metres, while DBW-25-123 intersected 80 metres at 0.39% copper from 127 metres.
The company also highlighted higher-grade intervals, including hole DBW-25-122, which returned 36 metres at 0.58% copper and a 15-metre sub-interval grading 1.03%.
Another notable intercept came from DBW-25-149, which returned 17.84 metres at 0.85% copper, including 8 metres at 1.71% copper, alongside additional broader zones of 21.42 metres at 0.38% copper and 26.65 metres at 0.38% copper.
Midnight Sun said four rigs are currently operating at Dumbwa, focused on extending mineralisation northward and testing strike and width extensions across the system.
Chief operating officer Kevin Bonel said the results continue to support the emerging geological model of a large, structurally controlled copper system. “What began as a geological concept has now been established as a significant discovery, with over 5.3km of strike now tested and supported by more than 40,000m of drilling,” he said, adding the system shows consistent expansion along strike.
The company said geological interpretation indicates a basement-hosted, strain-related copper sulphide system with variability in grade distribution along strike, but broad continuity across the mineralized corridor.
Drilling to date has focused on the upper 220 metres of the system, with mineralisation remaining open to the north, east and at depth. The company added that some deeper holes have intersected mineralization beyond 300 metres.
“We are developing a clear understanding of Dumbwa and can see the hallmark ‘pinch-and-swell’ geometry typical of major structurally controlled systems and have confirmed unequivocally that Dumbwa is a basement-hosted, strain-related deposit, geologically comparable in every way to Barrick’s Lumwana…Most importantly, we are continuing to establish meaningful scale with each step north expanding the system and mineralisation remaining open, alongside a clear plan to unlock additional mineralisation within zones identified through earlier drilling,” Bonel added.
Midnight Sun also said earlier laboratory issues at SGS Laboratories in Zambia have been resolved following internal audits and corrective actions, clearing a backlog of delayed assays. Results for 66 holes remain pending.
The company plans to continue Phase One drilling along an 11.2-km strike target, with an additional 200 holes and roughly 40,000 metres of drilling planned as it continues to expand the deposit.