OPERATOR WAS SCRAPING DIRT OFF THE TOP OF THE COAL WITH THE FRT BUCKET OF THE TRACKHOE WHEN THE BUCKET HIT AN OLD OIL WELL CASING PIPE 9""-6"" IN DIAMENTER. WHEN HE HIT THE CASING IT CAUSED A BI JOLT THAT CAUSED WHIPLASH TO HIS NECK. HE DID NOT EXPERIENCE PAIN UNTIL A FEW DAYS LATER