TW3 - Angle of Repose
Angle of Repose for Sand dune My last blog here was about cascade failure. It is one of my favorite scientific theories. Others include Chaos Theory, Queuing theory, and paradigm shift. And the subject of this blog: Angle of Repose - in short you can only pile sand (or shit or any other substance) only so high. (Note: the precise angle of repose varies per substance and moisture content but more of that later.) I choose sand as my illustration here because as children this may be our first encounter with the laws of physics as we sit in our sandboxes with our pails and shovels. I noted in a recent local news article that the Questa Moly Mine is putting off clean up of waste for 18 years. This is relevant to our topic because it has piled slag and dirt from its above and below ground mines to beyond the angle of repose. This is possible by misting the piles to solidify them. And it works for a while. Erosion by rain and wind can steepen that angle artificially beyond the natural an...