Believed to be the portal to a collapsed drift entrance on the upper level railway at East Kilns, Rosedale. Some believe it has been subsequently rebuilt after the mines closed in 1926 as all the drift entrances in this area are collapsed. The upper level railway in Rosedale is a fascinating place to explore and much less visited than the main lower level. Along the upper level the remains of High Baring Cottages where the miners lived and worked can be found, along with old engine beds, workshops and a gunpowder store. The drift entrance would have looked similar to the photo below when it was operational. !(http://www.northyorkmoors.org.uk/__data/assets/image/0005/1198787/3.-East-Mines-Entrance-with-miners-circa-1900-photo-T.-Smith-D.C..jpg)Thanks for the original asset creator : Land of Iron
Try "photogammery", "diorama", or "dinosaur", for some cool results.