Updated 3rd March 2020
This site is described on the web site of the Sociedad Espeleológica Alto Duero who have explored it. It would appear that the entrance has been located with GPS but the altitude (in brackets above) is wrong when plotted on 1:5000 maps.
The 1.5m diameter shaft is 3m deep and lands on a small ramp to the head of a 41m pitch. This is divided in 8m, 21m and 12m sections. The last part has another parallel shaft of the same dimensions.
It was possibly seen in February 2020 with a grid reference of 0454371 4796351.
website; file; anon., 2020a (January, February logbook)
Detailed survey: elevation on the SEAD website
On area survey: