Rio Tinto puts huge Winu copper-gold development in WA on the market with rumoured interest from South32

After teasing the immense potential of a copper discovery in WA’s north for years Rio Tinto is now sticking the once-hyped project —or at least a piece of it — in the shopfront window. The West Australian understands that since the beginning of this year Rio has been increasingly sounding out potential buyers or joint venture partners for the Winu copper-gold project about 320km east of Port Hedland. The ultimate cost to develop Winu is poised to be well into the hundreds of millions of dollars. The mining giant’s project update section buried in the weeds of its voluminous full-year results announcement lodged in February first alluded to a potential selldown. “In 2021, we reported our first indicated mineral Resource (at Winu). The pathway remains subject to regulatory and other required approvals,” Rio stated. “In parallel, we continue to explore options aimed at enhancing project value, including further optimisation of the current pathway and alternative development models and partnerships.” Rio repeated the same excerpt in its half-year results update tabled on the final day of last month. South32 has been touted by one industry source as an interested party. The BHP spin-out sold out of coal earlier this year for $US1.65 billion ($2.5b) and said it intends to siphon those proceeds into “development projects in copper and zinc”. South32 is on an extensive copper hunt spanning Argentina, Peru, the US, Queensland, the Northern Territory and WA. It will also spend about $3.3 billion to bring online its Hermosa mine in the US, which hosts the zinc-lead-silver Taylor deposit and the zinc-manganese-silver Clark deposit, as well as further exploration potential “including copper prospects”. A South32 spokesman said the company does not comment on market speculation when quizzed about the potential Winu interest. A Rio spokeswoman pointed to the company’s public disclosures in response to queries about a sales process. Winu was discovered in 2017 and kept a closely guarded secret, spawning theories that Rio had stumbled onto a copper version of Lasseter’s Reef. The fabled find sparked a huge exploration land grab in the lonely East Pilbara over the ensuing years. Rio at one stage had an exploration team numbering 180 on site at Winu, but the amount of money so-far ploughed into the project has also been shrouded in secrecy. Following the Juukan Gorge disaster in May 2020 Winu became bogged down in approval delays. The mine was meant to be in operation last year, but that milestone is still well beyond the horizon. It was only in December that Rio submitted its mining proposal for Winu to WA’s environmental watchdog. Winu has a resource estimate of 503 million tonnes at 0.45 per cent copper equivalent, including a higher-grade component of 188mt at 0.68 per cent copper equivalent, over a mine life of 41 years. For comparison’s sake Evolution Mining in December bought an 80 per cent stake in the operating Northparkes copper-gold mine for about $720 million. Northparkes has a mineral resource of 526.9mt grading at 0.55 per cent copper and 0.19 grams per tonne of gold. The Northparkes purchase came amid a backdrop of escalating copper fever among the world’s biggest diversified miners. Rio and BHP are both hungry for copper and the duo are branching out from Australia to satisfy their appetite for the battery metal. Over the six months to June 30 Rio says its copper exploration focus was predominately in “Chile, Kazakhstan and Serbia”.