Oct 28 (Reuters) - Elk Petroleum Ltd ELK.AX :
* Elk and denbury extend deadline for grieve discussions
* Elk and denbury have agreed to extend the termination of the negotiation period from November 1, 2015 to 30 November 2015
* Says capital development for the grieve co2 eor project is approximately 70% complete
* Source text for Eikon ID:nASX41830d