Well for one thing he is wrong about the acid treatment IMO and I believe that he as have others make this point as if it is very detrimental to ZEN. First there is a big difference between using acid to extract and using it to neutralize a basic solution created by the NaOH leaching (caustic). For one thing when you neutralize a basic solution with acid you get salts and water, no acid or base left. However when you extract with acid you produce acidic tailings that may be hard to neutralize and is detrimental to the enviornment. ZEN has said all along that they are using caustic and naturally it has to be neutralized with ACID. But it is being used only to eliminate the high pH produced by the base (caustic).
Now other producers especially flake producers must use high concentrations of Hydrofluric acid to extract or leach out the graphite and then end up with highly contaminated water which is difficult to remediate, this is the situation in particular with many Chinese producers or at least it is what has been reported. Since flake graphite is harder to purify to very high purity (99% or better) acid is generally used as an initial leachate process.
In any case I have read the PEA and this seems to me to be a non issue and it is not like ZEN has made some sort of sea change in how it is doing things, they are doing the extraction essentially as they have indicated all along, except that the results are being refined so that it can be scaled up.
