The characters refer to Williams's station as Dunsley Tracker, and it is labeled as such on the puppet-sized version of Lansfield's console. But in a close up shot of the console (a large-scale section of the same set), the caption above the alert light reads 'Densley' Tracker.
When Tony and Bob fall down the mine shaft, Bob is trapped face down, by two heavy looking timbers, his whole body has turned 90 degrees to his feet, but in the next shot we see him sitting up contacting International Rescue on his walke-talkie. The timber has moved inline with the one trapping Tony. Also both boys miraculously look in good shape, considering they have just fell over 20 feet down a mineshaft.