Walkabout increased the proven and probable ore reserve by 10% to 5.5 million tonnes, with the total graphite content (TGC) up 22% to 987,000t and the life of mine grade up 11% to 17.9% TGC.
Executive director Allan Mulligan pointed out that "grade is king" and the company had validated Lindi Jumbo as the highest-grade graphite project in Walkabout's ASX-listed, East Africa-operating peer group.
The company said the higher-grade would also allow better operational efficiency, with a 13% reduction in required throughput while maintaining annual production of 40,000 tonnes of flake graphite.
"The super-high-grade mill feed means that Lindi Jumbo is an incredibly robust project and positions the company to deliver the largest margins in the industry," Mulligan said.
He said Walkabout would now be able to take advantage of opportunities for increased market share and it would continue towards its goal of become "the non-China producer-of-choice for premium large-flake natural graphite".
Walkabout's shares rose 4.76% on the news Thursday to A11c (US0.8c), up 22.22% since the start of 2019.