Tidal I like your numbers but what would be the additional capex for an underground mine?

Also we are looking at this PEA in the global graphite context but as the USA has determined graphite to be a 'strategic mineral' and their desire to be self sufficient in graphite supply we have to look at domestic competition, can anyone name a US miner with a resource as large as ZEN offering graphite which can be mined with such a clean process producing a product of this purity and quality at this cost?