To determine whether a deposit has enough of a mineral to merit mining, companies use air-based geological mapping and drill for core samples.

WSJ: Exhausting the Earth's Resources? Not So Fast

They also noted the deployment of Russia's most advanced S-400 air defence system in Belarus and a parallel drill conducted by the Strategic Rocket Forces, the guardians of the Kremlin's nuclear arsenal.

ECONOMIST: NATO and Russia

These dry, 15-to-20-second statements are as fun to listen to as the dentist's drill, and make the air only under the strictest of rules: There can be no mention of products, and no appeal to buy anything.

FORBES: Public Radio Goes Begging