At least ten labourers were feared buried alive and several others injured when a portion of a hill caved in during mining in Obra area of the Sonebhadra district today. Police, however, has confirmed the death of four labourers so far and claimed that several were still missing. The incident occurred near Sharda temple this evening. Faujdar Singh was the contrator who was mining at the place. Senior police officials have rushed to the spot and relief operations started.