Rio Tinto Exploration Update – Winu project

As previously announced, Rio Tinto has discovered copper-gold mineralisation at the Winu project in the Yeneena Basin of the Paterson Province in Western Australia. This release provides new data on fourteen diamond drill holes and twenty-eight reverse circulation (RC) drill holes completed since the last report.

Significant intercepts for the forty-two drill holes are set out in Table 1 below. Results continue to indicate relatively wide intersections of vein style copper mineralisation associated with gold and silver beneath relatively shallow cover. The mineralisation remains open at depth and to the east, north, and south, with a currently defined strike length of approximately 2.1km. Drillhole details are included in Appendix 1.

Drilling is ongoing with eight diamond rigs and three RC rigs drilling at Winu and further results will be reported in the first quarter of 2020. RC and diamond drilling is continuing, with RC drilling primarily focussed on defining the extent and tenor of the supergene zone and diamond drilling continuing to test the extents of the deposit.

Rio Tinto continues to conduct cultural heritage surveys through strong engagement with the Traditional Owners.

Preliminary technical studies have commenced on the project including environmental baseline studies, geotechnical and metallurgical testwork. Construction of a gravel airstrip is near completion. In addition to the ongoing work at Winu, Rio Tinto is conducting exploration within the broader Paterson Province on its wholly owned licences and joint venture licences during 2019.

While results continue to be encouraging, the exploration project is still at an early stage and drilling to date does not allow sufficient understanding of the mineralised body to assess the potential size or quality of the mineralisation nor to enable estimation of a Mineral Resource. The assessment and interpretation of existing data is ongoing and is being used to help guide drilling for the remainder of 2019.