The thing I wonder about with NVA specifically is 'how low can...

The thing I wonder about with NVA specifically is 'how low can you go' in terms of grade. Just from a very quick look around at other low grade operations:

In 2012 the Paracatu mine, operated by Kinross Gold Corporation in Brazil, treated around 58 million tonnes of ore at a grade of around 0.4grams per tonne (“g/t”) to produce 466,709 ounces of gold. At December 2012 it had reserves of 1.4 billion tonnes at grade of 0.40g/t gold for a total of 18 million ounces of gold. The cut-off grade is around 0.2g/t gold.

For the 2011 year Boliden’s Aitik mine (within the Arctic Circle in Sweden) milled 31.5 million tonnes at a head grade of 0.24% copper, 0.16g/t gold and 2.0g/t silver. At the end of 2011 it had reserves of 710 million tonnes at a grade of 0.25% copper, 0.13g/t gold and 1.6g/t silver. Resources totalled 1.7 billion tonnes at 0.18% copper, 0.11g/t gold and 1.0g/t silver.

I think the metallurgy will be important for this, ho easily we can get that gold from the material.