There is a major storm in that part of the world and it is playing havoc with the VK9MT DXpedtion. They have announced they may be forced to leave the reef and return to Australia. No spots have been seen since about 1414Z on April 4.
Latest News: http://dx-world.net/2014/vk9mt-mellish-reef/
VK9MT Website: http://vk9mt.com/