Gelli Colliery is denoted on the 1st edition Glamorgan Ordnance Survey County Series mapping of 1877 (sheet XXVII, 2), with several levels, workers housing and coke ovens adjacent to the railway line at Gelli. By 1900 the colliery had expanded with a tramway and additional quarry to the south, on the lower slopes of Llwynypia Mountain. A second tramway has been constructed to the west with quarry. By 1919, the quarry is denoted as 'old quarry' with 'old coal level' and the tramway to the west has been dismantled.
Redevelopment has now taken place on the site of the old Gelli Colliery, with disused tips still evident on the lower slopes of Llwynynpia Mountain.
Photographed during aerial reconnaissance by RCAHMW on 16th October 2008.
L. Osborne, 21st November 2012.
