" This is the most important part of the film because it shows how we closed the old and most polluting part of the mine to protect the environment from over-exploitation," the mining guide explained to them.

" You have to be very careful because there is a complex network of tunnels at the bottom, and there have been several cave-ins in the past."

" That's why part of it was closed, because of the scandal of several dead miners - they all looked at the entrance with fear, like in horror movies