Butcherbird's measured, indicated and inferred resources now stand at 263 million tonnes at 10% manganese for 26.3Mt of manganese.
The previous resource was 180.8Mt at 10.8% manganese.
The resource for the flagship Yanneri Ridge deposit is 105Mt at 10.1% manganese, comprising 16Mt at 11.6% manganese in measured resources.
E25 said Yanneri Ridge's measured and indicated resources of 57Mt at 10.4% manganese were expected to yield 18.2Mt of plant feed at 28.1% manganese via crushing, scrubbing and wet screening.
The updated resource will underpin as maiden reserve, as well as a prefeasibility study.
The company believes the measured and indicated resources will provide feed well in excess of the 25-year high purity manganese PFS base case.
The PFS will focus on producing high purity electrolytic manganese metal and battery grade manganese sulphate for the battery market.
Shares in the company jumped 11.7% to A19c.