When your gut feel is based on extensive knowledge and experience over many years studying the industry @BkrDzn as yours is, that gut feel is more often right than wrong I reckon, so always good to go with it. Certainly was on this occasion.
My gut feel isn't always so accurate however - I had a gut feel that FRS were overstretched, trying to do too many things at once, including trying to buy gold mills off people who weren't yet ready to sell (Edna May from RMS), and were telegraphing all of their plans via their website which seemed like a serious case of over-sharing that could lead to less-than-ideal outcomes for the company, so I exited at just over breakeven at 50.5 cps on 13th May. Three trading days later they closed at 64 cps (+26.7% higher than my exit price), and while they've been up and down since, they remain 10% above my exit price, so I reckon my thinking was sound, but my timing was terrible.
However, in your case, with SMM, if the IT (investment thesis) was based mostly on positive drillhole results and your gut tells you those are now likely to be mostly dusters, it's an easy call to exit, as you did. Your gut feel was based on specifics. Mine (with FRS) was more based on the "vibe"...