cracked earth (IMAGE) Penn State Caption A byproduct of coal mining, acid mine drainage sludge sites, like this one in central Pennsylvania, are rich in critical minerals. Scientists with the CANARY project will take stock of resources in northern Appalachia that could contribute to creating a domestic supply of these materials Credit Sarma Pisupati/Penn State Usage Restrictions non commercial use only License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.