pityacka,
I suppose that because the pit's name was derived from the Norman family, the Delavals, it is fair to call it New Delaval. ( New Delaval as opposed to "old" or original Delaval)
My great grandad married in Blyth St Wilfred's in 1862. His address on marriage cert. was just Forster Pit, an earlier name of the community around the pit.
Before the pit was sunk ( circa 1860) that area was called Low Horton.
Michael