 In a logical conclusion town officials and many residents suspected the source of the hum was a massive $7 million mine ventilation fan with blades in diameter.From local reports and an informal investigation by "ABC World News Tonight", the fan operated by Jim Walter Resources, Inc. was generally thought to be the culprit.However, JWR (then owned by a subsidiary of Kohlberg Kravis Roberts) was in bankruptcy proceedings and denied its fan was the source.