Following the discovery of tin deposits around 1440, extraction began in the area surrounding the present-day sink-hole. The ore was largely mined using the fire-setting method. After the ore was removed, empty chambers (known as stopes) remained. The deposit site was honeycombed with such stopes. Eventually, the remaining pillars were unable to support the weight of the stone overhead. The first collapses took place in the 16th century, and the largest collapse occurred in 1620. It caused the destruction of large parts of the original mines, and a two-hectare funnel sink-hole appeared at ground level. Today, this sink-hole is 160 metres deep with a diameter of 400 metres, covering an area of around 12 hectares.