Fire crews attended an incident at a cement works at the weekend.
Staffordshire Fire & Rescue were called to a fire at Lafarge Tarmac in Waterhouses, near Leek, at 10.15am on Saturday, July 12.
Crews from Leek, Cheadle and Longton attended, aong with a water carrier from Leek.
Crews stayed on site overnight to put out the fire which had started in a coal storage hopper.
Group Manager of Staffordshire Fire & Rescue Brian Griffiths said: "The fire was in a hopper located on the fourth floor of a building on the site. Firefighters wearing breathing apparatus applied specialist foam solution to the fire to extinguish it, in what was quite a technical operation.
"The hopper contained 200 tonnes of stored coal which is used to fire the furnaces.
"The coal had self-ignited due to spontaneous ignition occurring, which although rare can occur if certain conditions are present.
"We managed to prevent the fire from spreading beyond the hopper and once we had ventilated the premises the business was able to carry on operating.
"Crews remained at the scene for several hours to ensure that the fire was under control and have since carried out a number of re-inspections at the site to monitor the temperature of the hopper. We will be working with the site management team over the next few days to ensure that the burnt material is safely removed."