Wellington fire crews were called to tackle a blaze at the Tonedale Mill for the second weekend in a row.
Fire fighters raced to the site late on Friday night after receiving reports of a skip fire.
On arrival they found a large skip containing burning building waste with plumes of smoke rising into the sky and covering the site.
Compressed air foam was used to extinguish the fire, before water was brought to bear from a nearby hydrant.
Both of the station's fire engines, and a Landrover, were deployed to the incident, which carried on until the early hours of Saturday morning.
It comes less than a week after an arson attack inside one of the mill's buildings.
On Sunday, July 9, Wellington crews were forced to dismantle a plasterboard ceiling after a deliberate fire began spreading to the roof of the building.
Sunday's fire prompted police to launch an investigation. A spokesperson for the force said: "We were called by the fire and rescue service following a fire in a derelict mill building in Wellington on Sunday, July 9, which is being treated as deliberate.
“Officers have carried out house-to-house enquiries in the area as a result.
“If anyone has relevant information and hasn’t yet spoken with the police, please call us on 101 and give the call handler the reference number 5223163876.”