I'm sure you are correct that the copper mineralization is likely copper sulphides - as I've never heard of any kind of pure copper being found in mining (I would think there would be pretty quickly [over geologic time] oxidation, sulfidization, or other admixtures of other elements).  I think whatever copper mineralization they referred to must have been of strong enough percentage for them to visually identify it as such.  That's why I consider it a great result, and something to be happy about.  Best regards - rodg45