On this page, about 1/3 down the way (it's in Russian) is a nice schematic of the hole that shows it's not vertical at all: https://realt.onliner.by/2015/11/19

On this page, about 1/3 down the way (it's in Russian) is a nice schematic of the hole that shows it's not vertical at all: https://realt.onliner.by/2015/11/19/kola https://realt.onliner.by/2015/11/19/kola The depth is the true depth, apparently.