A new ore transport system supplied by RBL-REI to the manganese mining company Comilog in Gabon, part of French global mining and metallurgy group Eramet, includes a package of belt conveyors at the Moanda mine site, the longest of which is an overland conveyor of over 6.5 km. About 5 Mt/y of ore is produced at the mine. This overland conveyor goes downhill from the minesite to the stockpiling area, following a negative slope with a height difference of -250 m and an aggressive trajectory involving a combination of four horizontal curves and vertical curves.
The most challenging aspects of the system which required RBL-REI’s depth of experience in this field include the design of the braking system due to the regenerative mode of the overland conveyor system, and on the other side the design of the roller configurations in the horizontal curves in order to keep the belt stable in any loading case, due to the high variations in belt tension.
The downhill configuration of the overland conveyor sees power generated when material is conveyed, at a level of few hundred kilowatts. Thanks to state-of-the-art frequency converters, the power generated can be used and consumed, and the overland conveyor belt can be controlled in any material loading configuration. And in case of power shutdown, the hydraulically-controlled braking system designed by RBL-REI and fitted on the drive pulley shaft has the capability to stop this very long belt in less than 10 seconds. The start-up of this major overland conveyor reference in western Central Africa is scheduled in the coming months.
For Eramet, the project is an important part of its wider strategy to reduce carbon emissions given that the downhill conveyor is electrically powered and uses regenerative technology. It also replaces diesel powered haulage trucks. It was recently mentioned by Leod-Paul Batolo, Managing Director at Comilog, when discussing the company’s decarbonisation trajectory at the first edition of a series of Biodiversity Meetings held at Lékédi Park in December 2022.
