The oldest mention of the mine dates back to the year 1365. Jan van Wambeke, dean of the chapter of Saint Servatius in Maastricht, wrote that he had received interest from the Duchy of Limburg due to the Bradersbergh mine. Mining took place where veins of ore rose to the surface. In addition to opencast mining, there were four thirty-meter-deep shafts in the Braesberg or Bleyberg, which led into an 800-meter mine gallery. The region is rich in heavy metals, as there are other quarries where zinc has been extracted, such as in Völkerich, Welkenraedt (Lantzenberg), Walhorn and La Calamine (Altenberg). In 1427, Philip the Good, Duke of Burgundy, rented the lead mine for one ninth of the revenue and for fifteen years to three men from Aachen: Jean Bernage and the brothers Herman and Geryt Pael. Under the reign of this triumvirate, the mine was extensively flooded. Then came three other tenants: Jean van der Moer, Guillaume Nekens and Pierre Danckaerts. According to Jean de Dalhem, intendant of the Duchy of Limburg, this second trio was still tenants in 1445. In the centuries that followed, setbacks, such as war devastations and floods, and prosperity alternated. At that time, the Braesberg, where the ore deposits are around a meter thick, was mainly mined north of today's village.