I was working at a open pit coal outside of kemmerer wyoming. i was driving a 50 ton coal truck on top of the west side of the property. i was driving about 18 miles per hour when i looked out of my right side window and observed a cigar shaped object going the same speed as i was. it looked like the front of a dc 3. i could see horizontal plates with rivets. it followed me for about 5 minutes. i went up a long hill to the top of the hill and i could see for about 15 miles and the object was nowhere to be found. so i stopped my truck,got out and looked in all directions and nothing was found.