From Halopedia, the Halo wiki
Conveyor belts are materials transport systems that consist of pulleys that have a continuous loop of material that rotates about them.
The Forerunners' gas mining facilities use conveyor belts that run along tracks to move gas containers to and from different locations within the facilities. There are two types of Forerunner conveyors, one made of a metal track belt, and one that uses a hard light track somewhat like the Forerunner energy bridge or Covenant gravity bridge technology.
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