RE:QuestionRefers to a "top-cut" in resource estimate methodology.
For example https://www.mdpi.com/2075-163X/8/8/348
And mention here https://www.micon-international.com/minex/
A top-cut is a statistical procedure as follows. Establish distribution of grades over various assay results to find out where the "outliers" start. Looking for the level of grades where you start to get very sparse data at very large values, which greatly affect the calculation of an average. Median is okay, but blah blah blah statistics.
Top-cut means they took all the high-grade gold results and truncated them to a lower level. Then they re-calculated the average grade from that interval using the lower level instead of the actual intercepts. They only adjust the high-grade stuff.
Standard statistical procedure that is done widely in mining and beyond. Many exploration companies don't included top-cuts and I've certainly never seen any junior mention it in first drilling results for a new discovery.
Why did Aton include it here? That's an interesting question... Combination of conservative attitude and interest in providing enough information to allow a more sophisticated audience to be comfortable with analyzing results themselves?