Found it -from Bingo :
"70 and 72 at the lower elevations hit iron at 2 and 4 meters, DH 69 was already excavated down to 30 m, so we started drilling in the iron, DH 73, the one behind the crushers, we hit the iron at 6 (we had graded 3m off the surface, so from surface was a total of 9 meters down)meters, took it down to 100m, and stopped, but we were still in the iron"