Employee was clearing the D-16 to D-11 chute from a flat rock that became lodged in the chute. Employee pulled the e-stop lanyard on D-11 and got on the 3 step platform from the south side of D-11. Employee used a bar to pry the rock from the chute. The rock came loose allowing the bar to drop suddenly and employee's pinky finger got between the bar and the metal skirting.