At present there is no mining of any kind in Greenland, but the cash-strapped and semi-autonomous country is keen to break away from financial and political dependence on its historical owner, Denmark.
Statehood!
The study proposed building a network of thousands of miles of tunnels under the ice, excavated as trenches and then covered over again. The tunnels would link together launch stations, each a minimum of four miles from any other and with at least three feet of ice cover, giving protection up to 30 psi overpressure. Overpressure is a measure of blast strength – 1 psi overpressure will shatter glass, 3 psi will collapse a wood frame house, and 5 psi will destroy all buildings save those made of reinforced concrete.
Six hundred ICEMAN IRBMs (modified Minuteman), enough to destroy 80% of the target list in the Soviet Union and eastern Europe, would be shuttled between launch stations through the tunnels, probably on trains. The network would be controlled by sixty launch control centers (LCCs), each with 100 psi overpressure protection. Small nuclear reactors would provide power to the LCCs and launch sites. The whole complex would cover 52,000 square miles, beginning 300 miles east of Thule.
11,000 men would be required to operate, supply, and protect the system, including 400 Arctic Rangers and 200 Nike-Hercules SAM operators. The remote LCCs would be resupplied from Thule via ski-equipped aircraft.
With 56,000 people? One-tenth the population of Wyoming?
Maybe there might be more with an *American* Greenland but nothing like enough for statehood to be politically plausible.
Of course the whole thing is academic, because the idea of sale, whenever mentioned, was "indignantly rejected by all political parties" in Denmark. https://groups.google.com/d/msg/soc.history.what-if/njge9xCMzpg/johVK_rY2xQJ
POD would need to be a different WWII with Denmark somehow becoming a huge battleground and becoming a wasteland. Suddenly the moneybags from Uncle Sam start to look a bit more appealing.
It would be a combination of Puerto Rico (non-statehood territory) and Nevada (a place where most land is owned by the government).
There would be some kind of commonwealth status or organized, but unincorporated territory to allow local self-governance within the limits set by Congress. Native Greenlanders would be given US citizenship instead of being US nationals.
Unlike the Pacific Mandates, the US intention would be to keep permanent control of Greenland because of its importance to North American defense.