EE was assinged to walk belts into section and see what work needed done, at the 1-a drive he helped to unload their tools out of the mantrip, He then walked over to belt and shoveled a couple of shovel's onto the belt, He stated to other EE that his chest was hurting. He sat down for a minute started to shovel again and said he had severe pain. He had 2 blood clots