EE was the opposite side roof bolter. EE was installing the second pin in the row. EE had drilled the 2nd hole and was putting in the sectional steels to finish the 6' hole. The steels did not connect. EE lowered the boom & struck the steel with a 1' wrench. After one strike, the steels sprang apart. The bottom steel struck EE in the mouth, breaking a tooth and cutting lip.