The hard disk, if it is still readable, belongs to the council (or waste company) now. It's not like salvage where who-ever recovers it owns it.

I'm amazed that a week or two of mining produced 7,500 BTC back in 2009. I know a guy that was mining back then and, come to think of it, I haven't seen him around work for months - I bet he owns a Caribbean island now.