When did SGC become operational?

[hedwig]

Assuming it took years to build the SGC, how long did it take for the Stargate to become operational?

This is information I found when I googled NORAD:

The Cheyenne Mountain complex traces its origins to 1956, when General Earle E. Partridge, commander of the Continental Air Defense Command, proposed construction of a new underground combat operations center to replace the outgrown and vulnerable above-ground facility at Ent Air Force Base, Colorado.

***
Excavation for the facility began in May 1961, and was completed three years later in May 1964. The NORAD Combat Operations Center became operational on February 6, 1966.

[Dave2]

So it would have only taken 3 years to build the entire complex over 20 stories deep? Including the basement area to explode a nuclear bomb?!

[KEK]

So it would have only taken 3 years to build the entire complex over 20 stories deep? Including the basement area to explode a nuclear bomb?!

The entire channel tunnel only took 6 years to build.

[DigiFluid]

So it would have only taken 3 years to build the entire complex over 20 stories deep? Including the basement area to explode a nuclear bomb?!

Uhh....what?

[fems]

I think he's referring to Singularity; Sam is doing an experiment with microscopic particles of naquadah and potassium in a lead-sealed room "in the sub-basement floor of the complex". Or he's confusing the SGC with the abandoned nuclear facility 20 minutes away from the SGC where they dumped Cassandra in the basement.

[Dave2]

Yes, it's about Singularity and Cassandra.......

[Snowman37]

Or he's confusing the SGC with the abandoned nuclear facility 20 minutes away from the SGC where they dumped Cassandra in the basement.

Bingo.