Interesting that the rescue capsule is based on a design used in an accident in 1963, (at much shallower depth).
It's actually based on a much older design, it is effectively a "Dahlbusch Bomb". Named after it's first successful use in 1955 when it rescued 3 miners after an underground fire at the Dahlbusch Colliery, Gelsenkirchen-Rotthausen, Germany.
It was used again in Germany on 7th November 1963 when 11 miners trapped in the Lengede-Broistedt ore mine were recovered.
This latter rescue inspired several films and documentaries. The German news channel N-TV were showing some of the 1963 news film and interviewing survivors from that rescue, getting them to compare then with now.
Preserved examples of Dahlbusch Bombs can be found at the Deutsches Bergbau Museum, Bochum and the Grube Samson mining museum - this one has a preserved man-engine, plus underground reversable winding waterwheels.