In the 1870s a further extension, the Wrexham and Minera Joint Railway, was built from Brymbo through to an end-on connection with the LNWR's Ffrith Branch, which ran from Llanfynydd to Coed Talon near Mold. This line was jointly operated by the GWR and the LNWR - the only line in North Wales to be so operated. The completion of this link through the Cegidog valley not only gave the GWR a route to Mold, but allowed the LNWR access to the North Wales Coalfield.