Mark Twain said the difference between the right word and almost the right word means the difference between "lightning" and "lightning bug".

Tell that to the Andersons of Mountrial County, North Dakota. The family lost a case because "drilling" doesn't mean the same thing as "drilling operations".

On May 3, 2004 and May 10, 2004, they granted mineral leases for five-year terms to what became Hess Corporation. Hess won a fight with the Andersons because the courts held that, under North Dakota law, Hess's "drilling operations" just before the five years expired kept the leases alive until Hess's actual "drilling" struck paydirt.

The leases all said that they wouldn't end so long as Hess conducted "drilling or reworking operations" on the Andersons' lands, which had become subject to a "pooling" unit. The Andersons urged that "drilling" didn't go with "operations" — that the "drilling or reworking operations" covered actual "drilling" or "reworking operations" but not "drilling operations". The Eighth Circuit disagreed. It affirmed summary judgment for Hess because the record showed, without dispute, that Hess had started getting ready to drill before May 10, 2009, although it began the actual drilling after May 10. Anderson v. Hess Corp., No. 10-3116 (8th Cir. Aug. 15, 2011).

Because the leases contained a "Pugh clause", production from the Hess well on one of the leases kept all the leases in the pooling unit alive.