Authorities at the London Metal Exchange took the unprecedented move to halt trading in nickel on Tuesday after prices for the metal doubled to $100,000 a ton. The sharp upsurge came in response to concerns over supply disruptions in Russia, one of the world’s largest nickel producers, and short positions by Chinese mining giant Tsingshan — a company that also has a huge presence in Zimbabwe.

Traders began panic buying in response to the wall of sanctions that arose around Russia this past week and has effectively sealed off the country from the global economy. The higher prices then sparked a crisis at China’s Tsingshan Holding Group, one of the world’s top nickel and stainless steel producers, that had extensive short positions on nickel (basically, they anticipated that the price of nickel was going to go down not up) and then they had to furiously start buying as much of the metal they could to cover their losses.