Hi Mel,
to me it also sounds like a Russian last name. Years ago, I had a friend Konovalova ('a' is the ending for a female's name).
Kon' means a 'horse' ('конь'). Other last names with the same root are 'Konev', just 'Kon' ', 'Konyavskiy', and others. 'Konovalov' was an old name for a vet, who 'pushed down' (the root 'val' = a verb 'valit' ') a horse to perform a procedure. 

Looking through many records regarding my family, I saw mistakes made in spelling. It could be that an officer who spoke Russian/Ukrainian by mistake wrote a different surname with the same root. But, of course, it is better to confirm with other available documents.

Elena Boldyreva,
Toronto, Canada
Looking for Rogovin/Ragovin: Minsk, Valozhin, Szack.