Miner was removing a guard to do maint. The guard slipped & landed on his left foot. The miner completed his shift & worked his next 4 scheduled days without incident. When he woke up the morning of 7/22 his foot was swollen had been on his feet all day 7/21. He came into work 7/22 & ran the plant with his foot elevated & iced. Miner left early to go to urgent care & get x-ray.