@ Patrick: You asked why the drop specifically today?
Don't know but I can guess.
Except for Barclay’s price cut on ACL on 27 Feb to R37/share and this weekend's China-issues, my guess would be yesterday’s Investor Day Presentation in Canada fuelled more flames:
Mittal yesterday said they are selling some Ukrainian output in other markers on a forecast for slower than expected demand in that growth region as domestic markets are down in Ukraine. Steel demand in Commonwealth of Independent States (that includes Russia & Ukraine), may increase more slowly than the 1.5% to 2.5% previously forecasted by Mittal.
The company provided an update on operations and medium-term plans, (unchanged from previous investor day last year), investors were hoping for additional cost cutting, hence some disappointment after announcement.