This oil store served the Maenofferen Slate Quarry and was constructed after 1939 according to plans held by J. W. Greaves Ltd. It is situated south of the River Bowydd within the main mill complex and north of a workshop range. It comprises a single storey building orientated N-S and measuring 6.7m x 5.1m externally, with a double door offset of centre in the N wall, 2 windows in W wall and single door in W corner of the S wall. It is constructed of coursed slate blocks with walls 0.6m thick and has a pitched slate roof. Inside there is a 3.8m long by 0.7m wide plinth along the west wall. Thestore was decommissioned in 1999 and a tank wagon remains in situ on tramway tracks inside the building.

References: Plans referred to are held by J. W. Greaves and Sons Ltd, Blaenau Ffestiniog

Louise Barker & Spencer Gavin Smith, RCAHMW, August 2011.