NEW : Mexico 's labor minister says Chilean experts will visit the mine Wednesday . NEW : In a blog post , he says the mine had 100 employees and had operated for 20 days . NEW : Mexican President Felipe Calderon said federal authorities were working with state officials to coordinate the rescue effort . Rescuers plan to work all night at the mine , somewhere in northern Mexico . The fate of the workers inside is unknown .
NEW : Mexico 's labor minister says Chilean experts will visit the mine Wednesday . NEW : In a blog post , he says the mine had 100 employees and had operated for 20 days . NEW : Rescuers plan to work all night at the mine , somewhere in northern Mexico . The fate of the workers inside is unknown .