But the International Atomic Energy Agency (IAEA) failed to disclose what the missing materials were, or whether it knew about them before they disappeared.
The sector is facing an even more uncertain future as the impacts from weaker demand and environmental regulations are creating more contractual volatility from the utilities to the railroads.
Production at its five operating silver mines in Mexico hit a record of almost 3.86 million equivalent ounces of silver for the second quarter ending June 30.