I was wrong, it wasn't Selwyn. It was North American Tungsten. They optioned the 3 Ace properties for two years and let them lapse when they started going broke. (from their 2008 annual report):

Limited work was undertaken on the Rifle Range Creek and the Bailey claims in the year. The exploration programs on these properties will be given low priority in the short term as the Company focuses on developing the Mactung property. During Q2 2008 the option agreement on the Three Ace claims expired, the Companyelected not to pursue renewal of the option agreement for these claims and accordingly wrote off the associated capitalized costs of $104,878.

http://www.northamericantungsten.com/s/FinancialStatements.asp

So, if this property is so good, then why did NTC allow it to lapse when they had a camp full of workers, the diamond drills, and all the equipment to put a drill hole in the ground a few kilometers up the road?

It could be they just missed out.