We are on site and coring has begun. The rig went up last Wednesday 13th and began washing/reaming into hole on 14th May. Had to go slowly to avoid starting a new hole. Back on bottom Friday afternoon bringing up core of beautiful crystal-rich welded ash flows. Problems on Saturday - core barrel would not release. After bringing up a dozen or so sticks of rod found the problem: a drill rod had split, making it impossible to maintain mud pressure on bit. Finally got the core barrel to release and found it "welded" shut. Tripping out found the outer core barrel had twisted off as well. Retrieved what we could; now milling out the bit, which is fused to the bottom of hole. Hope to be making core again by Monday.