In the US, thousands of tons of rock are extracted just to produce a few gold bars: mines move up to 500 tons per day, the ore weighs only 3 to 10 grams per ton, and 2 bars can be worth almost US$1 million. - CPG Click Petróleo e Gás

Google News: Mining reports: In the US, thousands of tons of rock are extracted just to produce a few gold bars: mines move up to 500 tons per day, the ore weighs only 3 to 10 grams per ton, and 2 bars can be worth almost US$1 million. - CPG Click Petróleo e Gás. This is a premium/paywalled source, so the brief is based on headline and available metadata only.