About: http://webisa.webdatacommons.org/164884246

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	Accessing the TBM with an emergency shaft from the surface is cost and logistically prohibitive, particularly if the tunnel is being driven at depth and under significant hydrostatic pressure.
http://www.w3.org/ns/prov#wasQuotedFrom	tunnelingonline.com