First of all, we should understand that there are two kinds of balance formulas for mineral processing: mass balance and metal balance:

Concentrate grade+tailings grade = raw ore grade (100%)

Concentrate grade * concentrate output+tailings grade * tailings output = raw ore grade * raw ore output.

It can be concluded that: raw ore rate/concentrate rate (beneficiation ratio) = (concentrate grade-tailings grade)/(raw ore grade-tailings grade).