Altitude:

120a Kacherlschacht (Quelli, F3) 1940m
120b Velo-Tracteur (F6) 1774m
120c Carcajau (F9) 1736m or 1731m
120d Altarkögerlhöhle 1670m

Location: In the south flank of Feuertal on the north side of Schönberg. Kataster says west of Schönberg, east of Franzosenschacht, 1626/119.

From the Quelli entrance, pitches p8, p19, p83, p33, p24, p17, p5, p33, p24, p9, p33, p27, p103 lead to -400m. Here one reaches a vast passage going up and downhill. The downstream passage emerges at the top of an 84m pitch. Below this a winding canyon interspersed with small pitches gives onto a 15m pitch and the end of exploration in 1976 at -708m.

The lower entrances lead by large phreatic passages to pitches which drop into a further large horizontal level which undulates between -410m and -500m. At -497m, this links to the main vertical system from Quelli. Using these lower ways in, exploration reached a sump at -913m in 1977. Following the large phreatic level away from Quelli goes for about a kilometre before breaking into the side of a colossal shaft at -414m. This is a 211m pitch to a choke at -625m. There is a possible way on across this shaft, which is, however, 20m in diameter.

The Austrian expedition of 1985 found a 3km horizontal passage, which brought the total length of the system to 15km.

In early 1997 the length was given as 19 808 m (Markus Wiesinger, personal comm.)

Discovery: Found in 1973 by Groupe Spéléo Alpin Belge under the name T3, but not pushed to any depth.

Exploration: Rediscovered in July 1976 by J.M.Piron and explored from 12th to 23rd of July by A.C.Toulon, S.C.Toulon, Lou Darbon & Spéléo Ragaie to a depth of 708m. Later sources refer to this group as 'an unheard of group of "Spéléos Provençaux"'.
The same group in 1977 discovered the two lower entrances, using them to explore to the bottom at -913m.
The Austrian expedition of 1985 set out to connect Feuertalsystem to Raucherkarhöhle and found a large horizontal passage, but no connection.

References :

78.2012

(GSAB) Spéalp 1 (June 1977) pp 33-49, Totes Gebirge : Description des principaux gouffres de la zone ouest du massif, Jean Claude Hans & Etienne Degrave
English Translation
En Français

78.2013

(GSAB) Spéalp 2 (1978) pp 66-67, survey, Feuertalsystem, Jean Claude Hans
En Français

The above description is translated mainly from these references by Andy Waddington and Jill Gates.