Ramgarh: At least four persons died of suspected asphyxiation while allegedly carrying out mining in a 40-foot-deep unauthorised mine in Jharkhand's Ramgarh district on Saturday, police said.The incident took place in forest land near Argada within Ramgarh police station jurisdiction.Ramgarh police station in-charge Naveen Prakash Pandey said all four bodies were recovered from the mine and sent for postmortem examination."Prima facie, it appears that they died due to oxygen deficiency inside the mine. The incident is being probed," Pandey told PTI.The deceased have been identified as Deva Bediya (30), Dablu Bediya (36), who hailed from Chhotki Tongi village under Giddi police station limits of Hazaribag district, Kishore Ravani (33) and Ashish Kumar Natwar, both hailing from Budh Bazaar of Ramgarh district, he said.General manager of Central Coalfields Limited's (CCL) Argada area, Satyajit Kumar, told that the incident site is outside the command area of CCL.He said the four villagers fainted due to reported oxygen deficiency in the nearly 40-feet deep unauthorised mine outside the CCL leasehold area in a forest land."They were taken to a hospital in Ramgarh where doctors declared them brought dead," he added.