There were no missiles, erectors, launchers, silo doors, hatches, warheads, fueling systems or solid rockets, launch control systems. Therefore not "nuclear missile tunnels". The whole concept was shelved once they learned what a pain in the ass it would be to build and maintain such a base, and the advances in range and reliability of regular icbms became obvious.

Camp century was built around the same time as the DEW line and other north warning system radars throughout Greenland and northern Canada, which had a more obvious use and necessity.