The longest belt conveyor system in the world is in Western Sahara. It is 98 km long, from the phosphate mines of Bu Craa to the coast south of El-Aaiun. The longest conveyor system in an Airport is the Dubai International Airport baggage handling system at 92 km. It was installed by Siemens and commissioned in 2008, and has a combination of traditional belt conveyors and tray conveyors. The longest single belt conveyor runs from Meghalaya in India to Sylhet in Bangladesh. It is about 17 km long and conveys limestone and shale at 960 tons/hr, from the quarry in India to a cement factory in Bangladesh (7 km long in India and 10 km long in Bangladesh). The conveyor was engineered by AUMUND France and Larsen & Toubro. The conveyor is actuated by 3 synchronized drive units for a total power of about 1.8 MW (2 drives at the head end in Bangladesh and 1 drive at the tail end in India). The conveyor belt was manufactured in 300-meter lengths on the Indian side and 500-meter lengths on the Bangladesh side, and was installed onsite by NILOS India. The idlers, or rollers, of the system are unique in that they are designed to accommodate both horizontal and vertical curves along the terrain. Dedicated vehicles were designed for the maintenance of the conveyor, which is always at a minimum height of 5 meters above the ground to avoid being flooded during monsoon periods. Source: en.wikipedia.org
Source:
http://en.wikipedia.org/wiki/Conveyor_ belt