I think "denlopviper and Meekal" have got it right.
Have personally witnessed another major Pakistani carrier do the said circling approach after breaking off the ILS 30. Not a problem if done correctly and within the rules. I don't have the minima handy but from memory around 1000' and 5km vis required for the circling approach. In the case I witnessed vis was reported below minima yet the a/c was allowed to continue on the circling approach. I watched the a/c disappear into the sandstorm only to appear some 5 or so minutes later on final approach. The crew that day definitely did not maintain visual contact with the threshold or it's surrounds as required.
If this is proven to be the case the crew will be crucified, I hope the procedures and ATC there are looked at closely as this is an ongoing illegal procedure which is done with the blessing of the controllers.
AUH