Recent Examples on the WebQuarrying, crushing, and grinding ultramafic rocks would cost only about $10 per ton of CO2 absorbed, Wilson and her team estimate. Robert F. Service, Science | AAAS, 3 Sep. 2020 Wilson and her colleagues sprayed the mine’s ultramafic rock tailings with dilute sulfuric acid, causing magnesium to leach out. Robert F. Service, Science | AAAS, 3 Sep. 2020