"During a railway expansion in Egypt in the 19th century, construction companies unearthed so many mummies that they used them as fuel for locomotives."
I think I remember reading that mummies were also used as fuel for the mechanical excavators used to dig the Suez Canal.
On a final macabre note I remember once reading that, in the 19th century, bone china tea sets were made from the ground up bones of soldiers killed at the battle of Waterloo. I have never been able to confirm this. Does anyone know if the story is true?