First Quantum said that Zambia's tax agency had demanded the taxes, saying they were on import duties, penalties and interest on consumables and spare parts.
Blankenship served time in prison for safety violations connected to a 2010 disaster that killed 29 miners and is seen as the weakest of the three candidates in the upcoming primary.
Chinese companies continue to aggressively try securing steady supply of lithium, a key ingredient in the making of batteries that power electric cars.