Lago Ercina

Speleogroup  title


Site list/GPS fixes

Walks/GPS tracks 

Coordinates used

LED projects:

 Lamp tests
 ISP isolators
 SMT boards

Expedition logs:

 1973, 1974, 1975,  1976, 1977, 1979,  1982, 1983, 1985,  1986, 1987, 1988,  1989, 2000, 2001,  2002, 2003, 2004,  2005, 2006, 2007,  2008, 2009, 2010,  2011, 2012, 2013,  2014


 The Battle of
 El Mazuco

Name: Rales System

Location: Above Rales village, near Posada

GPS: N43°24′43″ W4°53′39″

UTM: 30T 346.64 4808.39

Lambert: Fuentica: 5020 9793 50; Molino/Samoreli: 5015 9793 120; Un-named 5015 9793 110; Manantial de la Aldea 5022 9793 40

Map: Nueva (31-II)

Survey: OUCC 1973 »

Description: Length 2.4km, depth 110m. See OUCC Proc. 7 » for detailed description. Upsteam is Samoreli with impressive large chamber; water incoming from upstream sump. The stream exits and crosses Pozo del Molino – a deep open pit with remains of a mill. Downstream of that the large passage becomes a tight squeeze and duck (often blocked) leading to 12m pitch and a fine series of cascades and flowstone pools of the main stream passage. This joins the mainly dry passages coming down from Cueva de la Fuentica big entrance. The streamway continues alongside the Main Chamber series to a sump which is about 30m from the resurgence (Manantial de la Aldea).

Car parking fairly near Molino is at: N43°24′41″ W4°54′05″ 30T 346.05 4808.34.


1974 – through trip(?) from Molino to Fuentica down cascades and main stream

1975 – hot in wetsuits; surveyed upper Samorelli; down Molino to detackle and take photographs

1979 – wet through trip; lost rope. Mike, Bill, Elsa

1985 – tourist trip with Leopoldo + 7 others from Rales

1987 – tourist trip with Rafa + 1

2000 – no squalid pools, Mike impales back

2003 – GPS, descend Molino, short through trip

2005 – 20th anniversary trip with Leopoldo’s friends, etc.

2007 – an hour+ searching for route to Fuentica Main Chamber; photos


Possible site for hydrological experiments (tufa deposits in cave, etc.).

Expeditions to the Picos de Europa and elsewhere since 1973.
Please send e-mail to Mike Cowlishaw » ( with any corrections, suggestions, etc.  See also the SpeleoTrove speleology section ».
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This page was last edited on 2009-05-14 by mfc.