Black Rock Quarry Control Map. Door at the Upper Level NSC Power Plant checkpoint. Inside the Black Rock Lab.
This would lead you to a mold-infested area. The way to Atlas Chamber. Head down to the bottom to unlock the hidden location.
If you mean the one that you get into through that small visible crack on the left side of the map when looking from the control point Then yeah.
Continue towards the Quarry. Pick up the Security Clearance Level 5 and go through the door and into the service elevator. If the quarry is marked yellow instead of white then itll be the right place if not then itll be somewhere else. How to reach the Quarry how to detonate the charges and how to escape from the Quarry.