You would then have to argue that local mining corporation and nationalized industries are better for the environment than foreign mining companies in 3rd world countries. I don't think that is a obviously correct point. My understanding is that cottage mining (mostly of gold) is absolutely horrendous as there are no Safety and Environmental regulations. For national project I would assume a problem of finding the technical skill and technology, something that multinational firms have in buckets but might be difficult to find in an undeveloped domestic mining sector.