AVZ chart, page-6211

30/11/2018 Company announcement
Additionally, there is a significant increase in the global tin content to 300,000 tonnes and the tantalum content to over 13,200 tonnes, which is expected to provide a significant offset in the operating costs for the planned processing plant.”
A high-level observation is that the entire Mineral Resource could likely be
extracted from an open pit with a worst case final wastere stripping ratio of 1:1. Due to this observation the Mineral Resource is reported to a depth of 550 m below surface as it is reasonable to expect economic extraction to this depth.