THE manganese dumped on the Keetmanshoop to Lüderitz road in the vicinity of farm Brakwater was removed on Tuesday.
Manganese is a transition metal with important industrial alloy uses, particularly in stainless steel.
TradePort Namibia rail logistics manager Henry Katokele said personnel from the receiving depot cleaned up the manganese pile.
"The estimated quantity was just under one tonne, and TradePort is still busy investigating," said Katokele.
TradePort Namibia specialises in the import and export trade operations of transporting, handling and storage of manganese lumpy ore and other materials like gypsum, fertiliser and lime, as well as diesel in bond by utilising the Trans-Oranje Corridor.
The manganese is transported from the Northern Cape province in South Africa by rail or road to the Lüderitz port and then exported to various overseas markets.
It is, however, still not known who or which company dumped the manganese and why.
"We are busy at the same time reaching out to the contracted private road haulers to find out, and for anyone or company involved to stop the dumping of manganese immediately," said Katokele.