Two employees were bolting at the face. When finised in one area, operator lowered the canopy and was suppling his tray with roof bolts for the next place. As he laid some roof bolt on the tray he bumped his elbow the canopy. He had small 1/4"" cut. On Saturday it became swollen and he was ill with fever and nausea. He was treated at ER, released; no missing time until 12/13/04.