About 130 tonnes of germanium are produced globally each year, up from 50-70 tonnes twenty years ago, primarily from zinc residues and fly ash (waste from the burning of coal), with producing between 60-80%.

Source: https://investingnews.com/trilogy-metals-announces-potential-for-by-product-germanium-at-the-bornite-copper-cobalt-project-alaska/

Around half comes from zinc mining, half from coal - but it's fly ash from having burnt the coal.

Source: https://seekingalpha.com/article/4657091-ramaco-resources-stock-revising-my-opinion-down?source=feed_all_articles