KwaZulu-Natal police have opened an inquest after four construction workers were killed when a sand bank collapsed onto them at a building site in Ballito, north of Durban, on Saturday morning.Only one worker survived after he was retrieved from beneath tons of sand that entombed the workers.Emergency services reported that just before 9.30am, a sand bank collapsed at a site in Zen Drive in Ballito, entrapping five workers.IPSS Medical Rescue’s Samantha Meyrick said after midday, a call was made to halt the search.“Recovery was called off at this stage due to further collapses of the…