Minera Escondida Chile /global/scaled/1592x691x9x210x1000x435/Other-Tesa-Hotel 2.0-Referencias-Minera-Escondida.jpg BHP BILLITON’s Minera Escondida. These mines contain the biggest concentration of open-air fine copper in the world. Located in the Antofagasta (Chile) area, 3,400 meters high, no less than 4,300 people work in these mines. Part of the staff lodgings has been equipped with 220 TESA Donna electronic locks – these are the management rooms. In a dry weather climate, prone to sudden temperature changes, Donna locks represent the ideal complement for everyday use in extreme conditions when it comes to solidity and cycles.