Manono's Roche Dure pegmatite now has a measured, indicated and inferred resource of 400.4 million tonnes at 1.66% lithium oxide for 6.64Mt of contained lithium oxide, 300,000t of tin as cassiterite grading 750 parts per million and 13,200t of tantalum grading 33ppm.
Measured resources more than doubled.
The company noted the deposit includes 0.99% iron oxide, a potentially deleterious element, which is low compared to other reported hard rock deposits within ASX-listed companies.
The resource is contained within a 1600m strike length, comprising 95% of the Roche Dure pegmatite.
The company expects the deposit to grow further with five holes not included in the current estimate.
"With Manono now confirmed as the world's largest lithium deposit and drill results from the last quarter of 2018 still pending, we are confident that the Manono project will continue to grow and potentially become a world leading source of lithium," AVZ managing director Nigel Ferguson said.
AVZ shares peaked at A37c in January but were sitting at just 7.9c today.
The biggest single-day drop came when former executive chairman Klaus Eckhof sold most of his stake in the company in June.
"In terms of our share price performance, as owners of about 70 million shares, your board more than empathises with shareholders' disappointment," Ferguson told the company's AGM today.
"An analysis of the equity market performance of junior lithium companies around the world by Metal Bulletin has highlighted the negative impact this price fall has had on this group in particular.
"Having outperformed producers and developers while lithium prices appreciated the juniors have been the hardest hit on the way down. AVZ has been no different.
"We don't see any fundamental reason why our share price has fallen more than others in our peer group except to suggest that having gone up 2500% since the beginning of 2017 that our shareholders may have been more aggressive taking some of their ‘chips off the table'."
AVZ expects to release scoping studies next month into 5Mt per annum and 10Mtpa production options ahead of starting a full feasibility study in January.
All 15 resolutions at the AGM were passed, though about a third of shareholders voted against the re-election of director Hongliang Chen.