Pinge

A Pinge (pronounced "pinger", plural: "Pingen") or Binge ("binger") 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 sink-hole is frequently caused by the collapse of old underground mine workings that are close to the Earth's surface. Unlike natural landforms, a "Pinge" is a direct result of human activity. The term has no direct equivalent in English, but may be translated as "mining sink-hole", "mine slump" or, in some cases, as "glory hole".
Origin of the word.
In the original sense of the word, the mining terms "Pinge" or "Binge" go back to the activity known as "pingen" which meant something like "prospecting". An "aufgepingter" lode was one near the surface of the ground. The "Pinge" was therefore like a primitive, open pit mine.
Subsequently, the term was transferred to the funnel-shaped depressions that formed at the surface above filled or collapsed mineshafts. In lode mining, shafts and pits followed the strike of the lode and left behind the typical lines of "Pingen" ("Pingenzüge") associated with medieval mining that may still be seen, for example, in the Thuringian Forest, the Upper Harz Mountains, the Ore Mountains and the Eschweiler area in central Europe.
Later on, the term "Pinge" was applied to many kinds of depression left in the terrain as a result of mining activity, including the holes left by opencast pits in surface mining or the cave-ins above underground mines. The latter occurred either as a result of the unexpected consequences of active mining (often associated with accidents or disasters) or the subsidence above abandoned mines. They were sometimes willingly and knowingly accepted, for example, when mining was carried out by a method known as block caving.
A "Pingenzug" is a row of several "Pingen" in succession.
Types.
A "Pinge" can arise in different ways. In some cases it is caused by surface excavation. In other cases it follows the extraction of mineral deposits at a shallow depth and the associated collapse of the overburden that can result in subsidence at the surface. "Pingen" caused by surface mining generally date to the 16th and 17th centuries and are mostly only 0.5 - 1 metre deep. Deeper "Pingen", caused by collapse of the overburden, date to the 18th and 19th centuries. The "Pinge", which is caused as a result of the subsidence of the surface of the terrain, is usually surrounded by a ring-shaped mound (German: "Halde"). A number of "Pingen" form trenches up to 250 metres long and 15 metres wide.
Excavation.
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 "Pütts", 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 "Pingen". In the southern Ruhr, there are numerous such "Pingen" caused by surface mining. Subsequent erosion and collapse has produced funnel-shaped hollows, the "Pingen". Where "Pingen" have resulted from surface mining, small ring-shaped tips were often made by dumping the waste rock.
Another origin of "Pingen" occurred in a method of lignite mining called "Kuhlenbau" or "pit mining". Here, the brown coal was extracted by means of small, square, open pit known as a "Kuhle". As one pit was exhausted, it was filled with spoil from the next. In this way, a row of several hollows or "Pingen" was created.
Collapse.
"Pingen" were also caused by the mining of a lode near the surface that was not properly supported. When a deposit is exploited through underground mining, there are pressures and strains along the hanging walls. Over time, the hanging wall slips along the tear line into the mine cavity. "Pingen" are mining sink-holes covering a small area. But just like the continual, large-scale subsidence caused by large-scale mining at great depths, the overburden of mines near the surface collapses at regular intervals along a tear line. This subsidence of the strata is usually accompanied by an audible mining shockwave ("Bergschlag"). The actual shape of the "Pinge" is primarily determined by the different rock formations. In addition, the shape and appearance of "Pingen" is influenced by their age. A "Pinge" which is only shallow and only gently shaped over its entire surface is usually older than a "Pinge" with sharp contours.
How quickly an underground cavity near the surface collapses is dependent on various factors. Key criteria are the depth and the stability of the overburden. The depth of the "Pinge" is essentially determined by the size of the cavity created. If larger voids are created at less depth as in the mining technique known as "Tummelbau" ("underground pit mining"), the "Pinge" can be several metres deep. This sort of mining damage is particularly problematic if it occurs in a populated area.
"Schachtpinge".
A "Schachtpinge" ("shaft pinge") is a particular type of "Pinge" caused by the collapsing of old surface mineshafts. Especially in the early days of mining, very many smaller mineshafts were sunk. The shafts were predominantly lined with mine timber. Only in rare cases was natural stone, brick or concrete used for this purpose. If these wells were then abandoned, the wooden lining rotted over the years, fell away and then the pit collapsed, leading to the formation of a "Schachtpinge". The diameter and depth of a "Schachtpinge" depends on the size of the shafts, and whether the shaft had been filled in and the quality of the infill. Another cause for the emergence of a "Schachtpinge" was so-called "Duckelbau" mining. In this type of mining, the overburden in the area of the shaft usually collapsed very quickly, because ore was dug out just a few metres below the surface and, in most cases, not in solid rock.
"Stollenpinge".
A "Stollenpinge" is caused by the collapse of parts of a mining gallery ("Stollen") that is usually located at levels close to the surface or in weathered rock. They are generally easily recognizable from their typical asymmetrical shape and their shape of the depression which, unlike "Pingen" caused by excavations, is normally greater on the uphill side as well as their rather large mounds.
Examples of well-known "Pingen".
The following "Pingen" were formed by the collapse of overburden.