By Divya Rajagopal

TORONTO Shares of Canadian miner First Quantum Minerals fell as much as 24.1% on Monday after the Panama government said it will hold a referendum whether to scrap a mining contract that was awarded to the company earlier this month.

Following protests by thousands of people who oppose the open pit mine of First Quantum at Cobre Panama, President Laurentino Cortizo said on Sunday the government would hold a referendum on Dec.17 and the decision would be binding.

Panama's government and the miner had agreed on a contract which would guarantee the Central American nation an annual income of $375 million while allowing First Quantum's local unit to operate the Cobre Panama project, an open-pit copper mine, for at least 20 years.

First Quantum was not immediately available for a comment. Cobre Panama represents nearly 5% of Panama's gross domestic product and 1.5% of global copper production according to RBC Capital markets estimates.

By late morning, the stock was down 23.5% at C$21.35, while the benchmark Canada share index was up 0.4%.

(Reporting by Divya Rajagopal; Editing by Tomasz Janowski)