1 GUERRERO PALMA, P (2012) 'Roller mill development'. in: WC, April, p81-85. 2 GUERRERO PALMA, P AND HASTRICH, M (2019): 'Maintenance strategies to reduce the downtime of the quadropol® vertical roller mill' in: Cement International, 17(6), p36-39. 3 POLYSIUS (2008): 'Polysius commissions a modern 10,000tpd cement production line in