This, the 12th International Comminution Symposium (Comminution '21)is the postponed Comminution '20, which was affected by the Coronavirus outbreak. It is organised by MEI in consultation with Prof. Aubrey Mainza and is sponsored by King's Ceramics & Chemicals, Russell Mineral Equipment, Keramos, Starkey & Associates, Grinding Solutions, Glencore Technology, ME Elecmetal, Derrick Corp., ZEISS, Hudbay Minerals, Magotteaux, FLSmidth, Outotec, Sino Grinding International, Maelgwyn Mineral Services & Metso. Media sponsors are International Mining & Imformed, and the Coalition for Eco-Efficient Comminution (CEEC) are industry advocates.