Whoever said that nothing can be built here is just ignorant of either the terrain or construction and engineering. Levelling ground to build something at a certain location is done all the time, and the US military has done it in some not so habitable places. Just look at the infrastructure that is already present in these areas of Russia. How did they get all of those huge mining vehicles and equipment into such a hostile place if it is impossible?
Its remoteness is the perfect defense for a military installation, and we know the Soviets did this with their labor camps as well, as to make escape
foolish. The upside to building something secret in such a place is that only a satellite will be able to detect what is there. My advice to the OP,
check out whether the airspace is restricted. I do not know of all that many flights that would be going through that area, but if there are any
civilian flights, then the area may be a no fly zone for these flights. There are some big cities in east Russia, so this may be a good lead.
Building in areas like this is not impossible, it is just impractical for anyone but those who are doing something secret. The military would almost
nullify security by building out there. Another place that intrigues me about Russia is Tunguska. There is enough credible evidence both from the
scientists who have visited the area, as well as the indigenous peoples, to suggest that giant spheres of metal have sunk into the boggy terrain.