Haven't researched much, but I think it's the uncertainty...

Haven't researched much, but I think it's the uncertainty regarding the rail situation. It's not as bad as it seems on paper IMO they still have a 2nd rail option if all goes pear shaped.

Could also be that they were running low on cash, prior to the sale of tenements.

And then there's the conspiracy theorists, share price manipulation so that NM could purchase more?

That's all I can come up with at the moment. But wow, you bought purely based on a director buying? Hope it goes well for you and the holders (of which I could become, soon)