Twelve Thai boys and football coach trapped in flooded cave for 12 days
On Thursday rescuers started looking for a 'chimney hole' from the surface
Volunteers have accidentally pumped drained water back into the caves
A new phone is being taken to the cave after previous device fell in the water
Rescuers hope that caves can be drained and the boys can wade to safety
The young football team trapped underground in Thailand are still too weak to attempt to leave their flooded cave with two boys and their coach suffering from exhaustion, it has emerged.