The assertion is that the cancellation was "unlawful on public law grounds". The cancellation occurred on March 8th following volatility that saw prices doubling to over $100k a tonne in a matter of hours. HKEX, the parent company of the LME, dismissed the claim as "without merit".
LME Nickel is now trading (both cash and 3m contract) under $30K a tonne. Nickel is used in alloying to give steel (stainless steel) its corrosion resistant properties. LME Physical futures on nickel trade in 6 tonne lots with the nickel presented required to be Primary Nickel.