A mysterious sinkhole spewing fire and incredible heat has appeared in a Chinese hillside. Geologists and media have flocked to the desolate mountain on the outskirts of Urumqi, in Xinjiang Uyghur Autonomous Region in north-western China, since it appeared a few weeks ago. Scroll down for video . The hole appeared recently after locals noticed the ground nearby getting warmer . The heat blasting from the 'ring of fire' has been measured at 792C (1457F) from two metres away, reports People's Daily Online, and is so intense that experts can't get close enough to determine how deep the hole is. Video footage of the 3ft-wide hole shows locals igniting branches and grass by pushing it to the rim. Some Chinese internet users have branded it a 'gateway to hell' after viewing the pictures. Experts can't get close enough to determine how deep the mysterious hole is . The temperature has been measured at 792C - but that was from two metres away . Locals told Chinese media that they had noticed the ground in the area had been warm underfoot for some time. The hill is not in a volcanic area, and experts from Xinjiang Meitian Geological Bureau think the hole is caused by the layer of spontaneously combusted coal underneath the ground, which leads the surface layer to collapse. ‘The phenomenon has existed in the area for a few decades,’ Huang Wei, an engineer from the bureau told China Central TV Station. He added that smoke often comes from under the ground on this hill in the spring and autumn. Branches and grass that are held near the hole immediately catch fire from the intense heat . Experts think a coal seam may have spontaneously combusted below ground . Chen Long, a supervisor from Xinjiang Meitian Fire Engineering Bureau, said there used to be more than a dozen of small coal mines in the area in the 1970s. ‘Primitive mining and extinguishing techniques caused coal to burn deep under the ground,’ said Mr Chen in the same interview. ‘Operators didn’t seal the mines properly after business discontinued and this leads the underground fire to burn towards the surface of the earth.’ The local authorities have started drawing plans to put out the underground fire.
Locals had noticed the ground in the area was warmer than usual.
Experts can't get close enough to determine how deep the hole is.
Temperature measured at 792C from two metres away.
Thought to be caused by a coal seam spontaneously combusting.