underground photography workshop with Unloved Heritage? at the disused Dinas silica mine, nr Pontneddfechan. This silica mine began in the late 1800s and finally closed in the 1960s. The silica was used to make firebricks, which were exported internationally and became known as 'Dinas bricks' due to the purity of the mineral and the superior quality of the firebricks from these works.