The London Metal Exchange (LME) could ban or delist brands that are not responsibly sourced by 2022 under an initiative launched on Tuesday to help root out metal tainted by child labor or corruption. But the LME, seeking to avoid overly punishing small mining brands to the benefit of larger miners such as Glencore, said it would not single out cobalt and tin for accelerated auditing...The proposal is the largest step yet by the LME, the world’s biggest market for industrial metals, to clean up global supply chains and marks a shift from the exchange’s traditional role of requiring its suppliers to meet only metallurgical standards...the exchange would by 2022 audit brands identified as higher-risk with a view to banning them if they do not comply with requirements on responsible sourcing...Brands would be forced to publish fully all of their supply-chain information by 2024, the LME said...