The United States has imposed new sanctions on a Cuba nickel operation, triggering immediate changes at Canadian company Sherritt and adding pressure to Havana's already strained economy.Marco Rubio revealed the measures on Thursday.Three Sherritt directors, including chairman Brian Imrie, resigned with immediate effect after the announcement.Sherritt said sanctions announced by Washington on May 1 had already materially altered its ability to operate normally in Cuba.The company is involved in the Moa joint venture and also holds a one-third stake in Energas.The move matters because Energas accounts for about 10% of Cuba's electricity generation capacity, linking the sanctions to wider concerns... [Continue Reading]