Former Lewis Merthyr Colliery lamproom and fan house

Of rubble sandstone with protruding brick dressings and a Welsh slate roof. A single main storey rectangular gabled building of 4 bays to sides 2 to gable ends. S elevation has 2 tiers of semicircular windows with multipane/radial glazing, brick surrounds and concrete sills; round headed doorway to left (W) with fanlight and double plank doors. Gable ends E and W have single round window in apex and 2 semicircular below. N elevation has full height windows with multipane metal framed glazing and second door; basement has cambered arched windows and door. Attached NW is the fan house built of stone and brick with metal casing of fan and part chamfered brick evasee with corbelled top.

The lamproom is open to the metal framed roof with arcading above the lower bays. Travelling crane by Herbert Morris of Loughborough. Steps lead down to quarry tiled ground floor which is partly divided by metal partitions into offices and secure storage areas; adjacent are racks for recharging lamps. Steps down to fan house which contains a 1950s electric motor by David Brown and Sons and a Scirocco fan within its metal casing although fan not accessible at time of inspection January 1996.