Retort Base

A row of access doors runs along the bottom rear of the retort vessels at the Bathurst Gasworks. Each door is heavy cast iron, hinged into a brick surround, with bolts and a clamping mechanism that held it sealed during operation. The brickwork around the doors is darkened by decades of contact with tar, soot, and the heat of the retort house. The doors themselves carry rust across their working faces. The clamping handles still hang in position. The floor in front of the doors is stained where decades of operation worked tar and ash through the slab.

These doors were the tar removal access points on the retort vessels. Coal heated in a sealed retort drove off the volatile fraction as gas and left coke behind, but the carbonisation process also produced coal tar as a heavy by-product, which collected at the lower stages of the retort and had to be drawn off periodically. The Bathurst Gasworks ran coal carbonisation from 1888 until 1979 under council operation, with the plant rebuilt around 1960. Coal tar drawn through these doors became the site's defining contamination problem, and Bathurst Regional Council entered a Voluntary Remediation Agreement with the New South Wales EPA in 2006 to address it. The doors have not been opened in working order since 1979.