The soldiers belonged to an anti-guerrilla battalion fighting members of the Revolutionary Armed Forces of Colombia (Farc) in the SanVicente de Caguan area.
It wants the army to withdraw from a town near SanVicente, and consumer countries to pay for an alternative development programme and tourist centre there.
Meanwhile, the La Colorada (in Mexico), SanVicente (Bolivia) and Manantial Espejo (Argentina) mines posted increases in silver production compared to the third quarter of last year.