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cave digging
Cave Digging is the practice of enlarging undiscovered cave openings to allow entry. Cave digging usually follows a search of mountains and valleys in karst topography for new caves. Often it takes place underground in places where a large passage has clearly been backfilled with silt, or choked with boulders. Sometimes chisels or explosives can be used to widen constrictions in the passage when spaces are evident on the other side.
Digs are in unstable parts of a cave and often need to be shored up with scaffolding or concrete to prevent re-collapse. It can be a dangerous activity, depending on the circumstances.
==Geological cave indicators==
Most of the obvious caves in countries with a well-established caving community have already been discovered and explored, so cavers must search for new caves. This is most commonly accomplished while ridgewalking, the practice of scouring the countryside, in areas with cave potential, for new, previously undiscovered openings to the underground. These may be found in sinkholes, in rock outcrops or anywhere the ground is underlain by limestone or other soluble rock. Areas underlain by lava flows or where lava tube caves are found may also contain new caves.
If the discovered feature is either blowing or sucking air in great volumes, it is an encouraging sign and indicates that there is potential for a large or extensive cave beyond.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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