The present invention relates to the field of mineral and metallurgical processes, to comminution processing or disintegrating in general and to comminution processing by crushers and tumbling mills, and more particularly to a method and an arrangement for controlling a comminution process having a grinding circuit. An arrangement for controlling a comminution process according to the present invention having a grinding circuit (8), (20), (31), which arrangement comprises an imaging system (22), (27) measuring 3D reconstruction measurement data (33) for three-dimensional reconstruction of incoming ore (9), (21); a particle size analysis equipment (28) measuring particle size data (34) for calculation of the particle size characteristic value (38) of outgoing ore (10), (32); an ore characteristics data calculation block (39), said ore characteristics data calculation block (39) receiving a particle size distribution profile (36) of incoming ore (9), (21) and a particle size characteristic value (38) of the outgoing ore (10), (32), the said particle size distribution profile (36) being calculated and/or reconstructed from the said 3D reconstruction measurement data (33) for three-dimensional reconstruction, and the said particle size characteristic value (38) being calculated based on the said measured particle size data (34), said ore characteristics data calculation block (39) calculating ore characteristics data (41) based on the said particle size distribution profile (36) and the said particle size characteristic value (38); and a control block (44), (51) controlling the grinding circuit (8), (20), (31) based on the said calculated ore characteristics data (41).