"While the complex was designed to withstand a nuclear blast, it’s also ready to handle an EMP or electromagnetic pulse."
"Rose explained that an EMP won’t affect operations inside Cheyenne Mountain because the buildings are so deep inside the granite mountain."
"Also, the buildings were built of Navy-grade steel which reflects impulses and shields the equipment inside, Rose said."
“We have a high level of protection,” Rose explained.
Most of those “secrets” are well known to those that are paying attention.
They left out the part about the SGC being relocated to Dulce Base./s