And we could have used them to answer some important questions in physics, however, they got mined away: https://medium.com/the-physics-arxiv-blog/in-the-1970s

And we could have used them to answer some important questions in physics, however, they got mined away: https://medium.com/the-physics-arxiv-blog/in-the-1970s-scientists-discovered-a-2-billion-year-old-nuclear-reactor-in-west-africa-4472460b82c2#.u3tvy8ars https://medium.com/the-physics-arxiv-blog/in-the-1970s-scien...