I should also say, ARV could do what Altona did in Finland, and...

I should also say, ARV could do what Altona did in Finland, and just treat Carlow Castle for its gravity gold and store the sulphide on site in a wet tails storage facility while it works out what to do with it. This way could simplify the capital costs dramatically (say, $60-80M tops), recover a profitable amount of gold, and not destroy or sterilise the copper or cobalt resources ahead of a full metallurgical flow sheet being developed. Likeiwse, this strategy was used by Mutiny Gold on Gullewa to get past the transitional copper at Deflector; by throwing 2,000t of copper out as waste, they saved $130M in capex (off the top of my head) and jacked up the NPV and IRR...and Gullewa is going great. 

This is the kind of thinking ARV needs with Carlow Castle. Get something out of it now (the gold) and work on the base metals later.