Sydallt is a village in Gwersyllt community, Wrexham County Borough, north Wales.
[1] In 1877, the Llay Hall Colliery was opened in the village.
[2] Later, the Llay Hall brick works was established next to it to use the clay from the lower coal seams.
[3] The colliery was privately owned by the Llay Hall Coal, Iron and Fireclay Company until it was nationalised in 1947.
[2] It closed shortly afterwards due to a serious underground explosion.