Ann: Strike Takeover Offer for UIL Energy, page-107

A while back, a poster (can't remember who) talked about how SN asked the senior geologist to take a look at some old seismic data for the tenement, and from that, they identified these new prospects.

As such, possible answers to your question (why didn't the big boys buy these tenements first) is that the simply didn't look, or didn't have the same data that SN told our geos to look at, or started with the wrong assumptions (i.e. that deeper targets were unlikely to exist).

In short, I don't think we should always assume the big boys are the only ones who can do good, innovative research. And sometimes the small guys have to think outside the box.