Sources involved in the project have told Reuters the aim is to give manufacturers a way of ensuring the cobalt used in lithium-ion batteries has not been mined by child labour.

"The demand to make cobalt more sustainable is going to continue growing, meaning there is a will to find a solution and blockchain will be part of that," a source told the wire service.

Human rights group Amnesty International put the issue of child labour in the spotlight with a report in 2016 into tech companies' sources of cobalt and followed it up in November, calling on electric vehicle manufacturers to do more to check on their cobalt supply chains.

The DRC Chamber of Mines addressed the issue last month, with president Charles Kyona calling on mining companies to establish a system of a responsible supply chain in line with the chamber's ethics charter, and regional, national and international legal instruments.

China established a Responsible Cobalt Initiative in October which companies are signing up to, aiming to establish an inclusive, sustainable and responsible cobalt supply chain.

Under the blockchain pilot scheme being planned, each sealed bag of cobalt produced by a vetted artisanal miner would be given a digital tag which is entered on blockchain and its details updated with every transaction through to the smelter, Reuters reported.