BLOCK MODELLING 101!!
When up-blocking to a specified SMU (smallest mining unit) size, I always tend to forget which parameter to use for weighted averages (WA). A friend of mine reminded me to use the diagram as illustrated below: you work with the bottom variables to do the weighting. So if you want to calc the WA of relative density (RD), you use Volume as the WA. Volume and Mass however are additive variables, so you just add them to calc your new up-blocked Volume and Mass. Likewise for Yield, you calc the WA by using the Run-of-Mine mass (RoM). The qualities are a bit easier: for Run-of-Mine (RoM) qualities, you use RoM mass as the WA. For Product qualities, you use Product Mass as your WA.