The previous April 2018 resource was increased to 15.17 million tonnes at 0.61% coppper using a cut-off grade of 0.184% copper after a 2018 drilling programme comprising 8,604m in 93 holes.

Phoenix Global said the resource's copper volume rose 37.4% to 73,872t, zinc was up 108.3% to 29,813t, gold rose 75.9% to 139,000 ounces and silver volume increased 69.6% to 6.03 million ounces.

CEO Dennis Thomas said the resource had a combined metal value of about US$800 million.

"We have an additional 4.3Mt of inferred resources, but only measured and indicated resources will be used for the purposes of completing a bankable feasibility study," he said.

"At a 0.325% cut-off grade, we now have over 10Mt in the measured and indicated category at a copper grade of 0.61% copper. This will be the cornerstone for the development of a low capital cost fast-track openpit oxide operation, to produce 8,000t of combined copper and zinc annually.

"Our team will look to optimise the project economics as we progress the BFS, as well as evaluating the potential for early cash flow from the gold and the silver."

Phoenix also reported a maiden inferred sulphide resource at the recently discovered Red Star zone.

"Drilled for the first time in 2018, Red Star is showing an inferred resource of 103,500t with an average grade of 173.4g/t silver, 0.85g/t gold, 0.33% copper, 3.85% lead, and 0.92% zinc," Thomas said.

The Red Star resource included 338t of contained copper, 957t of contained zinc, 2,800oz of contained gold, 577,000oz of contained silver and 3,988t of lead.

"We look forward to the continued evaluation of the Red Star Zone, which has all the makings of a highly profitable mine," he said.

Phoenix's shares (AIM:PGM) were 1.34% lower Tuesday at £6.94 (US$9.08) per share, up from £5.66/share at the start of the year.