Canadian miner First Quantum Minerals said on Wednesday it was seeking $20 billion through international arbitration after Panama ordered the closure of the company's flagship copper mine in the central American nation.

The company has lost over half its market value after Panama's surprise order in November to shut Cobre Panama mine, one of the world's largest. The country's top court ruled First Quantum's contract was unconstitutional following nationwide protests against its operation. The mine accounted for about 40 percent of the company's revenues.

"We have provided a minimum value sought in those proceedings of $20 billion, reflecting an estimated fair market value of initial investment," First Quantum chief executive officer Tristan Pascal said on an earnings call, adding the company could potentially get much higher amount in damages and interest.

However, Pascal said that arbitration is not the preferred outcome for the company.

"We would really rather come to a resolution with the state of Panama that results in the best outcome for the people and for the company.

First Quantum has filed arbitration as part of the free trade agreement between Canada and Panama. The company separately has also filed a case at the International Chamber of Commerce (ICC) arbitration process, under the termination clause in the ICC contract.

For the quarter ending Dec.31, First Quantum reported a net loss of $1.45 billion. The stock was trading up 2.8 percent in late morning.

(Reporting by Divya Rajagopal, writing by David Ljunggren, Editing by Marguerita Choy)