If it muddies the waters using an Au eq then like you are saying...

If it muddies the waters using an Au eq then like you are saying do not use it , for me it is just a way I can relate to a base metal project as most of the little knowledge I have in mining is related to gold mining .
Some gold miners with base metal credits ie DRM use flotation to form a concentrate just like G1A proposed to do , but all processing even CIL/CIP tends to costed out on a per tonne basis and then mineralised output factored in .
Yes as mentioned Room and Pillar mining tends to be cheaper than long hole mining but then you also need to look at mineralised value per vertical meter no matter what form of ore.