b'Ocean explorers and entrepreneurs have been thinking about how to scoop up mineral-laden deposits on the seafloor since the HMS Challenger dragged a few up in a bucket during its globe-trotting scientific voyage in the 1870s. A century later, the CIA used deep sea mining as a cover story for a secretive plan to recover a sunken Russian nuclear sub. Now, it\\u2019s a serious engineering proposition.\\nLearn more about your ad choices. Visit podcastchoices.com/adchoices'