The Altenberger Pinge (shaft collapse) is located immediately northeast of Altenberg town (which was substantially rebuilt after World War II due to extensive damage inflicted by Allied air raids in spring 1945). It represents the largest of several collapsed underground and/or open-worked tin mines in the nominated property, developed in such a manner because they exploited ‘stockwork’ tin deposits (intense networks of veins and greisen enriched with pervasive low- grade ore). Is up to 160 m deep, has 450 m in diameter and occupies an area of 12 ha. The main period of the collapse of block cave mine workings was between 1545 and 1620 and substantial enlargement further occurred in the 19th and 20th centuries.
The intensive exploitation of the Zwitterstock deposit started in 1436 and whilst, comparatively, the overall average ore-grade was low (0.36%), it was constant, and the hill was full of tin. By 1576, 124 ‘mine fields’ were crammed into an area of less than 5 hectares of the surface of the Zwitterstock. The owners of these fields sunk shafts and extended drives and stopes using fire setting. As a result, the deposit was hollowed out to a depth of about 200 m; below which the ore grade rapidly falls away. The thickness of pillars between cavities was often barely one metre and, progressively, these failed in the 16th century. In 1620, large parts of the mine collapsed and a funnel shaped surface depression of 2 ha emerged.
1663/64 saw the unification of the mines to the Zwitterstockgewerkschaft zu Altenberg (mining corporation) and tin mining activity was centralised. The formation of Altenberger Pinge enforced a new exploitation strategy of driving galleries from the surrounding rock into the crushed zone of the ore deposit. Mining continued as late as 1976-1991.
