At Reported date and time i was walking down a unnamed service road parrallel to railroad tracks and grain elevators.sky was clear, no wind at all, apx. 90 degrees. i looked up to observe object hovering north at apx 4 Mph. the object appeared to come off of the top of the grain elevator. object was orb apx 18 inches in diameter about 90 feet off the ground rotating very slowly counter clockwise. Object had the same pattern on it as a tennis ball and was colored a greyish-tan.I watched it for apx 15 minutes as it moved north and slowley gained elevation until it could not be seen.No audible sounds were observed including surrounding area. I have seen alot of strange things in this area, but that was the best observance.