The problem with averaging down in any stock is that it becomes mental accounting to most people. They think of it as just bringing their cost base down. You need to look at any new money you put into the market as fresh....what is the best possible way i can use this money in the market. You don't want to throw good money after bad just to make yourself feel better by bringing your cost down thereby in your head, partially correcting your first mistake. Averaging down is not always a bad move, but many times it is.
As for Nb205, I know next to nothing about the rare earths market other than the margins are not what they once were and you only need to look at Molycorp, the biggest player in the game to see how thats working out. I am actually suprised IMG has not spun this asset off or sold it. Most people that buy gold stocks want pure gold plays. Several of the seniors have learned the hard way on that front and have sold off non core assets such as copper and zinc components. Pure gold plays often take a premium in the markets against hybrids. Unfortunately for many.....there isn't much premium in any gold right now.