Don Shirley goes there almost every year. So it is still open for diving. But as Meadowwalker and Germie said, it is a vast cave, in the middle of nowhere and all dive facilities must be taken along. So we run expeditions to the site, and divers wanting to join on a trip should be CCR, Cave, Trimix and IWR qualified to go there.
As for mapping.. too deep and too vast to do it the traditional way. We have mapped the upper areas to 80m. You need specialised mappers to do more.