Well the only argument that I think the company could come up with (and it's not a great one) is that Full Metal Minerals, which owns property surronding Pebble to the west and South isn't actively drilling their property either.
But then again Teck Cominco gave away Pebble for pennies and now it's the biggest unmined deposit in the world. Not so smart move by an experienced mining company.
Now if Northern Dynasty today wanted to offer more shares to pursue another project, it could because it has built significant shareholder value in the biggest unmined deposit in the world.
Rio Tinto and Anglo American have invested heavily in Northern Dynasty. Now in about 5-7 years we'll find out whether Pebble will be mined. In that same 5-7 years, Liberty Star could delineate a 10+ million ounce gold deposit, build shareholder value, then if they want to dabble in uranium, that's fine just use the shareholder value built up from the gold deposit. But in 5-7 if Pebble is permitted and Liberty Star hasn't done anything to the property, Rio Tinto and Anglo American will buy the company for pennies, and people would wonder why didn't Liberty Star put a drill bit to a project that had so much potential.
Hell if I was Rio Tinto, I'd buy out all of the surronding property around Pebble TODAY, start drilling it out, then work out a deal with Anglo American to mine the entire district.
Trust me it would take Rio Tinto much less than 1.4 billion dollars (the amount Anglo American paid for a 50% interest in Pebble) to buy the surronding area. Rio paying say 200 million (to buy the surronding area) to possibly make 10's of billions of dollars. Sounds like a good risk for reward investment to me.