RE:RE:Henrich are you wrong.I am also not sure if you can just apply an average grade over the mined rock.
There are some very strongly mineraized areas that can be identified visually
https://twitter.com/BayhorseSilver/status/1430919575575666689
These areas can be mined first and the less mineralized areas can be left on a pile until the throughput is high enough to deal with less mineralized material. Therefore, the absolute amount of rock required to extract the 300 tons of concentrate that meets the specifications may be not so high.