Cees I am no expert on digging or alloys.

It was clearly stamped on the back that it was made from Lynite.

Which according to the internet is principally an Al alloy (with possibly a small amount of Mg).

I repeat – I was only asking if someone had seen it before and not dictating the physics of crashing or corrosion.

perhaps as it is American and made from aluminum and not aluminium – it may survive better – IUPAC joke.