The Arah mining facility was an Imperial oridium ore mine located in the Belt of Arah. It mined and refined the oridium ore into fuel supplied to the TIE Phantom project.
The Interior of the Mine
The Mine resided on one of the larger Asteroids of the Arah belt; A flat, irregular disk surrounded the asteroid's equator and contained extensive pipe and tunnel systems, presumably required to refine and transport the mined materials off the base.
The disk tunnels were interconnected with the central mining area by three access tubes, whose entrances were shielded.
The center of the asteroid was hollowed out by giant escalators , 'rock scrapers' literally;. The bulkheads holding up the reactor and escalators were littered with sentry guns meant for taking out falling debris, to avoid damage to the structure.
On the asteroid's north pole, as well as an maintenance access tunnel to the core, resided a part of the mining facility, likely for fuel storage and crew habitats.
The north pole structures of the Mine
The mine was established in secret at some point before 3 ABY. A YT-1300 freighter pilot was aware of the existence of the mine and subsequently tried to inform the Rebel Alliance of this discovery; However, he was close to Dreighton when he tried to contact a Rebel Patrol; This brought the attention to the Imperial garrison on the planet, intercepting the Corellia Star with TIE fighters and eventually boarding the vessel, killing anyone on board.
Rookie One was able to retrieve the battered freighter from the Imperial base, and with a full record of the message in their hands the Alliance decided to strike against the facility, forming temporary Rascal Squadron. The facility and its TIE/IN interceptor defenders were destroyed soon after, bringing an end to the Imperial operations in the Belt of Arah.
If Rookie One is killed in Chapter 6 "The Mining Facility" a game over cutscene shows the Belt of Arah as Rece asked to Merrick where did Rookie One went and Merrick asked her if he is behind her.