I'm not totally sure what all the detailed reasoning was in the...

I'm not totally sure what all the detailed reasoning was in the MEP office, but I recall that other companies have been pinged for being aware of information having a material effect on a share price, being aware and seeing photos of sulphides in drill core means that someone in MEP has made the call that the release of descriptions or even photos of the drill core would have a material effect on the MEP share price.

The Iris drill core photos aren't particularly high grade but they do contain enough sulphides (especially Chalcopyrite) to allow some people to make a "rough" visual determination of the expected Cu grades in the core. This would be an estimate only, but it looks like the decision was made that it could have a "material effect" - hence the trading halt.

After all - the ASX compliance guys can hardly claim that visible sulphides in drill core definately won't have a material effect on the MEP share price can they? Especially when no-one has the assay results yet.