I always thought it was something to do with particle distance rather than the content
It also works with sawdust, flour and, the one I used to experiment with, coffee whitener. The Mythbusters did one on a massive scale with coffee whitener.
www.youtube.com/watch?v=yRw4ZRqmxOc
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shovelboy This is bad - Two minutes to Belgium, Tue 3 Mar 2009, 23:56,
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