For other uses, see Mine (disambiguation).
The facility is composed of several large chambers that are not directly connected and can only be visited using linked portals. Vortigaunts are the main laborers in the facility, serving as both guards and worker drones. They remain indifferent to intruders unless supervised by Alien Controllers which command them to attack. In the mines, the Grunts are produced inside large blue containers that are transported throughout the facility using conveyor belts. The grunts within the barrels are already in a battle-ready state as they will engage in combat like any other grunts if the container is breached. The facility has a portal connected to the Nihilanth's lair and several elevators that lead to higher floors of the mines. It also includes numerous healing chambers that the Vortigaunts make use of, implying the work in this area can be dangerous.
The mines only appear towards the end of Half-Life in the chapter Interloper. Gordon Freeman arrives there using a portal from elsewhere on Xen. In the first area, only Vortigaunts are present, and they show no hostility towards him. In later parts, however, the presence of Alien Controllers ensures that the Vortigaunts become hostile. Gordon also finds the bodies of Black Mesa survey team members, indicating that Black Mesa had previously discovered the facility. Eventually, Gordon fights his way through the mines and reaches a portal that leads him to the Nihilanth.