Abstract: In autogenous grinding of mineral material in a grinding mill with a screening wall a method is provided for enabling the removal of at least three different fractions without the need of the screening wall being divided into sectors, thus increasing grinding material turnover and grinding capacity, by passing through openings (8) distributed over the screening wall (7) a mixed material fraction containing all material fractions having a maximum particle size less than or equal to the largest size opening for screening coarse material in the size intended for use as a grinding charge in a further mill (23) and dividing up the mixed material fraction into at least three fractions in a classifying apparatus (13), by always taking out from the classifying apparatus (13) at least a fine fraction, a coarse fraction and a medium coarse fraction, the latter two fractions being kept separate for permitting, as required, diversion (38) of the coarse material fraction as grinding charge to following grinding steps, the