Black Rock Processing Control Bridge. Remedys adventure is a bewitching bewildering time. Head back down to the walkway by following the signs for Black Rock Processing then cross the bridge go up the stairs to the right and drop down into the office.
Fast travel to the Upper Panopticon Control Point and head across the bridge to Fortified Unit. Find a Black Rock Prism. Black Rock Quarry Entrance Hidden Location 2.
The pathbridge leading to the Black Rock Processing is now accessible.
So that big empty area with the bridges on either side is called a firebreak. If you continue to follow the signs you will come to a giant abyss. To get to the Black Rock processing area in Control you need to build yourself a bridge. Its two walls of black rock over a bottomless pit with bridges and doors on either side.