EE was in the process of changing a boom swing pin on the 401 roof bolter. EE had removed the old pin and set it in the tray of the bolter. As EE was driving the new pin in place the old pin which weighs approx. 33 pounds fell out of the tray smashing EE's left pinky finger. EE received 3 stitches and was diagnosed with a fracture of the pinky finger.