Pinge

in Germany's Thuringian Forest A ( , plural: ) or ( ) is the name given in German-speaking Europe to a wedge-, ditch- or funnel-shaped depression in the terrain caused by mining activity. This depression or sinkhole is frequently caused by the collapse of old underground mine workings that are close to the Earth's surface. Unlike natural landforms, a is a direct result of human activity. The term has no direct equivalent in English, but may be translated as mining sinkhole, mine slump or, in some cases, as glory hole.

in Germany's Thuringian Forest A ( , plural: ) or ( ) is the name given in German-speaking Europe to a wedge-, ditch- or funnel-shaped depression in the terrain caused by mining activity. This depression or sinkhole is frequently caused by the collapse of old underground mine workings that are close to the Earth's surface. Unlike natural landforms, a is a direct result of human activity. The term has no direct equivalent in English, but may be translated as mining sinkhole, mine slump or, in some cases, as glory hole. . Key: = mound; = ; = coal seam; = side wall slippage; = original pit; = groundwater Initially, the extraction of ore or coal took place near the surface at outcrops of the main deposits. Excavations of seam-like deposits were carried out by digging out bowl-shaped depressions, the so-called , that miners hewed out along the course of the seam with picks and shovels. Once digging reached the water table, groundwater ran into the hole. If the quantity of water was so great that it entered the pit faster than it could be drained, the holes filled up with groundwater. To make matters worse, the ingress of water and the consequent softening of the soil reduced the stability of the side walls. For this reason, the pit was simply abandoned in such cases and a new one dug some distance away. Over the years, these hollows became . In the southern Ruhr, there are numerous such caused by surface mining. Subsequent erosion and collapse has produced funnel-shaped hollows, the . Where have resulted from surface mining, small ring-shaped tips were often made by dumping the waste rock. Another origin of occurred in a method of lignite mining called or . Here, the brown coal was extracted by means of small, square, open pit known as a . As one pit was exhausted, it was filled with spoil from the next. In this way, a row of several hollows or was created.

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