The Tennessee Department of Transportation said yesterday at least one lane of westbound Interstate 40, shut down by a rock slide in the isolated Pigeon River Gorge, could reopen by Feb.14. Spokesman Mark Nagi with the Tennessee DOT said that was a rough estimate.  The slide Tuesday about one mile from the state line in Tennessee shut down both westbound lanes. Eastbound lanes remain open. Tennessee transportation officials were getting bids for the cleanup work yesterday. The problem is a 1,500-ton boulder on the mountainside that transportation officials worry will fall if it’s not removed. Around 11,000 cars per day travel the westbound lanes through that area.