Seems to be the Ordnance Surveys mistake, its called Bunton on every OS map since the first edition, but all the mine literature and plans call it Bunting.
Methodism in Swaledale
by John Ward (1865)
Amongst the mines we may relate
Surrender, Kinnin, and Blakewaite,
With Bunting, Blind Gill, Beldi Hill,
And celebrated Swinnergill."