wdurham,I think you ( and Stemis,unionhall and pehaps Daz ) are very much the exception for looking at this as a project and not as a share play,although nothing wrong with a genuine trading approach.
I have a very mixed record on mining investments and where I have lost it is mainly through flawed valuation of the assets in the ground in cash terms.
While I maintain a small investment in TMC I do not anticipate adding to it until the means to produce the cash ( actual shipments ) are in place and I will be happy to forego 50p 100p or therabouts to reduce risk.