Rock chip sampes will usually return higher grades than ore. That said, ...

"The Copper Queen Mine was a copper mine in Cochise County, Arizona, United States. Its development led to the growth of the surrounding town of Bisbee in the 1880s. Its orebody ran 23% copper, an extraordinarily high grade.[2] It was acquired by Phelps Dodge in 1885."

https://en.m.wikipedia.org/wiki/Copper_Queen_Mine

And, Hay Mountain is judged to be part of the "Bisbee formation" in terms of underlying bedrock. So, yes, 20 percent copper per ton of ore is what you are looking at here, potentially.

VP