TWO EES WERE WORKING FROM AN ELEVATED MAN BASKET. THEY WERE CONSTRUCTING AN OVERHEAD COVER ARRANGEMENT FOR A MINE SUBSTATION (UNDERGROUND). WHILE WELDING STEEL 4"" CHANNEL TO 4"" H BEAMS ON THE SUPPORT FRAME. THE WELDER RECEIVED A SEVERE ELECTRIC SHOCK AND THE HELPER A MINOR SHOCK. EE WAS SENT BY CHOPPER TO THE HOSPITAL. AFTER ABOUT 3 HOURS HE WAS ALL RIGHT.