Raipur (Chhattisgarh) [India], February 28 (ANI): Four labourers were killed while two others sustained injuries after a portion of a rock caved in an iron ore mine area in Dantewada district, following a landslide, a police official said. The deceased were identified as Bittu Bala (26), Tushar Bala (49) and Nirmal Bala (56), all residents of West Bengal and Santosh Kumar Das (29), a resident of Bihar. According to Additional Superintendant of Police, R K Burman, the incident took place at around 3 pm on Tuesday afternoon, during construction work of a retaining wall as part of the Screen Plan…