Evaluating ore-sand by-products at Cadia’s porphyry copper-gold mine for construction applications

• Ore-sand can be produced as a by-product from porphyry Cu-Au ores. • Cadia ore-sand has more rounded particles than m-sand, similar to Brucutu ore-sand. • Coarse particle flotation after roughing improves its quality for construction. • Cadia ore-sand shows promise for use in concrete and shotcrete. • It can fully replace natural fine sand without affecting performance. The global consumption of aggregates—including sand, gravel, and crushed stone—is estimated at around 50 billion tonnes annually. Although these materials are geologically abundant, their extraction often occurs in sensitive environments, leading to significant socio-environmental harm. Additionally, the mining sector produces about 13 billion tonnes of tailings each year, with over 50 billion m 3 stored in tailings storage facilities, many of which are unstable, and 9 % located in globally protected areas. Innovative solutions are required to overcome this unsustainable way of extracting and producing minerals. Our research has introduced ore-sand, a potential source of sand at scale that can also help reduce tailings production. We present empirical evidence demonstrating the technical feasibility of producing ore-sand as a by-product of processing porphyry Cu-Au ores. We validate this concept using a representative sample from the silicate-rich HydroFloat output at Newmont’s Cadia operation in Australia. Our assessment of Cadia ore-sand indicates that it is a suitable alternative to river sand for concrete and shotcrete applications, complying with Australian Standards and commercial formulations. Our findings suggest that Cadia ore-sand possesses unique particle shape properties that place it between manufactured sand and river sand. Coarse particle flotation after rougher (desulfurisation) flotation results in a coarser ore-sand product, improving its quality and allowing it to fully replace natural fine sand in concreting while achieving comparable performance. This circular economy approach offers a low-impact alternative source of sand, which is particularly crucial given the rising demand for copper and other materials necessary for the energy transition.