Tech investors are sounding out how the U.S. taking Greenland would affect the viability of critical and rare earth minerals mining there, CNBC has learned, as Washington ramps up its pursuit of the Arctic island.Greenland has found itself at the center of a geopolitical firestorm over the past week as the U.S. has threatened to annex the self-governing Danish territory, citing national security concerns. Commercial opportunities have also come into the spotlight.In the past week, Critical Metals Corp, a co ...