Adamantium Stuffs should be Bedrock Veins, how old is your GT6 Version? Because in newer Versions, if you picked up just Rocks then it’s a GT5 Style Vein, and if you picked up “Raw Adamantine Ore”, then it is a Bedrock Vein.
I would recommend digging a 1x1 hole to Bedrock in the center of each chunk for the 5x5 of chunks around the Rocks you found.