These rooms housed the quarry administration. This is where the telephone equipment connecting various parts of the quarry to the workshops was kept. This, too, is where the stores were kept. In the main stores, iron, steel and other large items were kept on long racks. There was also an amazing variety of screws, nails and washers, with every drawer correctly and minutely labelled.

Once, a tally board hung by the door in this place (you can see it now through the entrance archway window). Every man who worked in Gilfach Ddu had his own tally, to be presented at the end of the day. Men who called at the stores were not allowed to go into the stores themselves — they had to ask for what they needed at an adjacent window. A notice warned that they should not linger too long!