legal recourse I believe Entree may have legal recourse -- but against RIO, not the GOM. I believe that RIO may be liable under the contract between TRQ and Entree over their share % and the inclusion of the mining licenses in the final OTLLC deal (I might be getting the details confused). As a party RIO is probably jointly and severally liable, meaning that Entree probably has a case in a normal jurisdiction (US). However, this may not be the case if the contract includes clauses saying that TRQ is not liable for anything caused by the GOM.
The main point now is that it comes down to Entree's relationship with RIO -- the relationship between ETG and the GOM is now completely finished.