Large double pit with tunnel to Glynrhonwy Lower.*

The site retains two impressive pits with extensive rock-cut tramway formations and sections of tunnelling. Remains also include inclines and several buildings associated with the workings. A fine wooden bridge survives, along with the abutments of a former bridge that once carried waste across the road.

Originally separate but contiguous with Glynrhonwy Lower. It was developed in the mid-nineteenth century from earlier small diggings and grew into a substantial operation consisting essentially of two major pits worked in tandem. The quarry featured a notably complex internal rail system, partly locomotive-worked, with some tracks dramatically cantilevered along sheer rock faces. In 1882 it produced 2,181 tons with a workforce of 90 men. It was initially linked to the Ffridd incline, but following amalgamation all output was routed through Glynrhonwy Lower via a connecting tunnel. Average production later stabilised at around 3,000 tons per year. Activity steadily declined until only two men remained at work when the quarry closed in 1939.