Proposed vertical shaft excavation.

Frontiers A Case Study of Deep Shaft and Open Face Tunnelling Induced Excessive Ground Settlement in Water Rich Strata in Guangzhou, China

Small-diameter vertical shafts constructed in the shallow space of steep mountainous areas - ScienceDirect

Tunnel Shafts: Types, Construction, and Advantages - The Constructor

Deep vertical drilling in New Zealand opens a new chapter for large sustainable drainage reticulation projects – Australian Tunnelling Society

Tunnel & Trenchless Construction Services, West Coast

Tunnel Shafts: Types, Construction, and Advantages - The Constructor

BHP Jansen Shaft - one of the largest potash mines in the world - Arup

Drilled shafts Keller North America

Vertical Shaft Sinking Machine (VSM) - Herrenknecht AG

Atsushi Yashima's research works Gifu University, Gifu-shi (Gidai) and other places