[cctalk] PDP-10 TENEX mini-dump format

I've got a 7 track tape here that was written on a PDP-10 TENEX setup. It's identified as a "mini-dump" tape. I can extract the data (PDP-10 5 char/word) successfully, but the format of the block headers (seems to be about 6 words) eludes me. I'd like to be able to use the original file names. Does anyone have information on the mini-dump structure? TIA Chuck