The Associated PressShares of Endeavour Silver Corp. fell Tuesday after the silver miner said that an "illegal work stoppage" was blocking access to some mines in Mexico. Endeavour said that if resolved shortly, the labor dispute shouldn't affect its production guidance for 2012. The Canadian company, which has three operating mines in Mexico, said it has contacted Mexican authorities and taken steps needed to declare the stoppage illegal and end the blockade. The move by its contract workers is illegal because no formal complaints have been made against the company and no strike notice has been filed, Endeavour said. The company's Las Torres mine and flotation plant are shut down, and mining operations have stopped at the Peregrina mine. Operations continue at its El Cubo mine, but a nearby plant will run out of supplies from the Las Torres plant soon. Endeavour's U.S. shares fell 32 cents, or 3.3 percent, to $9.30 in afternoon trading.