First published by Money Metals here: https://www.moneymetals.com/news/2020/06/10/top-primary-silver-mining-production-falls-to-lowest-002053

The era of high-grade silver mines may be coming to an end. Remarkably, the top primary silver miners’ average yield fell to the lowest ever in 2019. Which begs the question, will high-grade silver mines become extinct in the not-so-distant future? Well, if we look at the data, it seems to be already happening.