Canadian minerals exploration company Avalon Advanced Materials has set its sights on a closed coal mine site in the US state of Illinois, where geochemical sampling has found elevated levels of rare-earth elements (REE) and other metallic elements, such as cobalt, nickel, lithium, manganese and zinc in waste materials.

The company has signed a binding letter of intent with a private US firm Coal Strategy Advisors (CSA) to earn an up to 50% interest in the Will Scarlett rare-earths recovery project, near Marion.

The rare earths are found in the acid mine drainage (AMD) and in the precipitates generated from lime treatment of the AMD to neutralise the acidity.

Avalon says sampling of the precipitates and AMD has revealed high concentrations of total rare-earth oxides in excess of 500 ppm. Also notable is that, unlike most hardrock rare earth resources, no significant uranium or thorium associated with the rare earths has been detected at Will Scarlett.

The potential for economic recovery of rare earths from coal mine wastes and fly ash has been receiving a lot of study in the US. This has accelerated recently with the introduction of new US government initiatives to reduce reliance on China as a source of these critical minerals.

The company believes that these unusual occurrences represent an interesting opportunity to create a new primary rare earths supply relatively quickly and at a low cost compared with typical hardrock resources.

CSA has applied for funding being made available by the US government for new rare earth supply chain projects.

Avalon and CSA plan to proceed with analytical and process testwork to confirm concentration levels and the most efficient extraction process to recover the rare earths from the AMD and precipitates.

Avalon and CSA will enter a formal joint venture agreement once the full scope of work required to advance the project to initial production is determined.

"In our research to date on rare earths in coal mine wastes, Will Scarlett stands out as exceptional in terms of the levels of rare earths present in the AMD. Like our East Kemptville tin project in Nova Scotia, Will Scarlett provides Avalon with an opportunity to extract value out of previously-mined waste materials at a relatively low cost, and potentially fully remediate the long term environmental liability associated with acid mine drainage at the site,” says Avalon president and CEO Don Bubar.