TriciaK,
 
 I have not heard of planz like zat !  
 However here's some stats of Blyth coal leaving the harbour.
  Exported coal broke thru the million tons mark in 1888. 
  1937= 6.6 million tons. 1938= 5.8, 1939= 5.8, 1940= 4.1
   1941= 3.9, 1942= 3.9, 1943= 3.5.
 In 1961 Blyth exported 6,889,317 tons. Blyth ( and Europe's)
  highest ever total. It went downhill thereafter through efforts
  of UK government policy decisions !
   Plans to block the harbour for whatever reasons would have 
   had a major impact on the value of Blyth's commerce.
  Michael