Driller and mechanic were performing drill maintenance/repair when driller began to double over attempting to vomit. Chest was sore and left arm was numb. Mechanic rushed them to the ER at Chanute Med. 1 hr later, mechanic was told that driller had a heart attack and was going to Freeman Med in Joplin, MO. Driller was placed in ICU. On 2/17, employee was released.