EMPLOYEE WAS MEASURING THE HEIGHT OF THE HIGHWALL IN FIERSTEIN QUARRY FOR TEST DRILLING. THE WEIGHT ON THE END OF THE TAPE MEASURE GOT STUCK. THE EMPLOYEE WENT TO THE EDGE OF THE HIGHWALL TO F REE THE TAPE MEASURE. THE SURFACE WHERE HE WAS STANDING GAVE WAY AND HE FELL ABOUT 15'. THE EMPLOYEE WAS NOT WEARING FALL PROTECTION.