BT BQ 99b(52)var. :ההיא שעתא דנפיק מתותי סיכתיה‏ : the time when it (masc.!) was in place of its stamping
See the entire entry for mn@tḥwt prep. from below

BT BQ 99b(52) :ההיא שעתא דנפיק מתותי סיכתיה‏ : at that time when it was just coming off the coin press †
See the entire entry for sekkā, sekkəṯā n.f. peg, large nail