Disused adit

On my wanderings around north-west England I sometimes happen upon interesting mining remains. This disused adit marks the entrance to upland coal workings in the thin seams of the lower coal measures. The area in front of the adit has been partly filled with rubble and silt and would once have been quite a bit lower. I suspect that there was once a structure over the entrance and that the little alcove on the left may have been for placing a lamp or candle.