Sun 13th December 2015. 18:20. BBC One
Duration: One Hour
This episode of Countryfile was filmed in the Peak District, part of it being around Castleton. It was to look at the contrasting features of the White Peak and Dark Peak. The first part was looking at Reef Limestone, Matt Baker met a geoligist on Treak Cliff Hill who explained how Reef Limestone was formed, how it shaped the landscape of Castelton and the valley basin. The geologist preeded to show some rock outcrops with examples of fossils, that identify that this was created underwater environment in past warmer climates.
The geologost showed a simple experiment where rainwater was poured onto limestone, this showed the chemical reaction as the water dissolved the rock, that water ran into the cracks and joints; and that this would eventually create underground passages and chambers.
The end of the episode was filmed in Speedwell Mine showcave which demonstrated these underground passages and chambers, and how they have been used by lead miners. Mat Baker was talking to John Harrison, Speedwell Mine Director as they went down the Speedwell Level on a boat. John was explaining how the lead miners used black powder, pick axes and chisels to mine this level on a pre-defined bearing to hit a specific point underground, passing through veins, faults so they could mine the lead; and harness the rivers so they could flood this tunnel. This allowing them to bring the lead out on boats in the flooded tunnel. The Bottomless Pit was the final destination, with John showing a piece of Galena and Matt washng the rock so examples of the minerials stand out.
Glimses of Winnats Pass, Treak Cliff Hill, Longcliffe Hill and Castleton were shown in this episode.