This is a grassland fire. The firefighters are using "flat beaters" to extinguish the fire. In order for a fire to burn it needs heat/oxygen/fuel when the beater comes down on the grass that is on fire it removes the fuel by impacting it. it also temporarily removes the heat by bashing it out the way. this is really hard/hot work. the reason why they are using beaters could be because they could not get the fire appliance close enough to the fire or there is no hydrants or open water in the area. Firefighters also need to act fast at grass fire incidents because the fire can move very quickly - sometimes faster than you can run.