I first spotted this one towards the end of July last year. It's been getting bigger since then.
DCC Highways have concluded that the top road has slipped a few millimetres towards the hole which is not enough to close the road but is a cause of concern, particularly because its just downhill of the section of road which they spent vast amounts of time and treasure fixing only a few years ago.
This shot looking the other way gives a better impression of the line of the vein. See if you can spot the entrance to Speed Mine at the top of the picture!
For those unfamiliar with the area: