Deep Navigation Colliery Deep Navigation Colliery Deep Navigation Colliery was a coal mine in South Wales, that operated from 1872 until 1991. Located next to the co-developed village of Treharris in the borough of Merthyr Tydfil, on development it was the deepest coalmine in South Wales Coalfield by some . Producing the highest quality steam coal, it powered both the Cunard passenger steamers RMS "Mauretania" and RMS "Lusitania" in their successful attempts at the Blue Riband prize for the most rapid Atlantic Ocean passage. The mine is also thought to have been one of several locally that provided coal to the RMS Titanic;
Sigsbee Deep Sigsbee Deep The Sigsbee Deep (Mexico basin in the U. S. Board on Geographic Names Advisory Committee on Undersea Features (ACUF) Gazetteer), is a roughly triangular basin that is the deepest part of the Gulf of Mexico named for Commander Charles Dwight Sigsbee, USN, Assistant U. S. Coast and Geodetic Survey, commanding officer of the USC&GS George S. Blake which discovered the feature during its mapping of the Gulf of Mexico. As described below there is some confusion of names that apply to the basin or a particular point in the basin with both being found in technical and popular