Column densities for each dip stage derived from the respective equivalent width for all Si and S ion absorption lines detected in ObsIDs 3814 (yellow diamonds), 8525 (green triangles), and 9847 (blue squares). Negative values of the equivalent width correspond to absorption lines. The column densities of lower charged ions increase with increasing dip depth, whereas column densities of highly charged ions decrease with dip level. Be-like Si XI and Li-like Si XII lines are contaminated by the Si He z emission line.