WHILE WORKING ON AN OPEN LEACH STOCKPILE, SEVERAL EMPLOYEES SMELLED AN UNUSUAL ODOR. SHORTLY AFTER SEVERAL EMPLOYEES EXPERIENCED SORE THROATS, HEADACHES, LUNG IRRITATION. EMPLOYEE WAS SEEN AND RELEASED THEN ON 10/21/2014 EMPLOYEE WENT BACK TO DOCTOR AND TOLD NOT TO WORK UNTIL FURTHER NOTICE.