Lago Ercina

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Site list (GPS fixes) Walks (GPS tracks)  Video clips Panoramas

Coordinates used

Electronic projects:

 Bat detector
 Lamp tests
 µ-controlled lamp
 SEPIC-based lamp
 ISP isolators
 Making 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, 2015, 2016,
 2017, 2018, 2019
 Mexico, New England


 The Battle of
 El Mazuco

Name: Cueva Bolado (Herrería)

Location: 2.5km S of Llanes (3.5km by road). From the Llanes–La Pareda road, turn left about 0.6km after crossing the main N634 road. After 100m or so, some 100m before a quarry entrance, there is a widening in the track, with lake to east, to park. Go west over small stream (drain) and wooded path 50m to big walk-in cave entrance.

GPS: N43°24'00" W4°45'56"

UTM: 30T 357.14 4806.96

Map: Porrúa (32-III)

Survey: (none)

Description: Easy walking cave with crystals, at the end. One side passage is gated off, presumably has paintings or other archaeological interest.


2004 – locate entrance

2004 – general explore

2005 – more photographs, etc.

2010 – tourist trip & dark adjustment experiment

2011 – UV torch tests

2012 – test 3W LED lights and surveying reflectors

2019 – general explore and discovered stream and resurgence



Crystal flow in Bolado

Crystal flow in Bolado

Bolado - modern art

Bolado - modern art

Cueva Bolado formations

Cueva Bolado formations

Expeditions to the Picos de Europa and elsewhere since 1973.
Please e-mail Mike Cowlishaw ( or Bill Collis (
if you have any corrections, suggestions, etc.   See also the SpeleoTrove speleology section ».
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This page was last edited on 2019-07-06 by mfc.