In the southern Mathavia Mountains, within Deo Esari's contaminated Abandoned Lands, the Choking Mines sit at the precise intersection of void and air leylines. The convergence causes air to spontaneously appear and cease to exist — miners can be breathing normally one moment and instantly choking the next as the air vanishes from their lungs.
The mines were worked despite their danger because the leyline convergence produces rare magical minerals and crystals found nowhere else. Bodies recovered from the shafts are found frozen mid-task, no wound, simply out of air. Whether the site was ever formally closed alongside the rest of the Abandoned Lands is unclear; the Titanic Priesthood's archives are sealed.