Rio Tinto exploration update

(Posted on 11/03/19)

Rio Tinto has discovered copper-gold mineralisation at the Winu project in the Yeneena Basin of the Paterson Province in Western Australia. The Winu project is located approximately 130 km north of the Telfer mine and 350 km southeast of Port Hedland.

The discovery was made by Rio Tinto Exploration (RTX) who are conducting a programme targeted at finding copper mineralisation in the Paterson Province. The exploration programme consisted of eight reverse circulation (RC) and twenty diamond holes drilled on exploration licence E45/4833 between December 2017 and the end of 2018, totalling 13,286 metres (1,473 m RC and 11,813 m diamond). Assays for all RC holes and fourteen diamond holes were received and validated at the time of preparing this release. Assays are pending for the remaining six diamond holes (partially or totally); partial results are included for two holes. Diamond drilling recommenced in mid-January 2019. Four holes have been completed for 1,409 metres during 2019 and are pending assay results.

Assay results to date indicate relatively wide intersections of copper mineralisation associated with gold and silver. Vein style copper, gold and silver mineralisation beneath relatively shallow cover which ranges from 50 to 100 m. The mineralisation remains open at depth and to the east, north and south.

While results are 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 will be used to help guide the drilling in 2019. Significant mineralised drill hole intercepts above 0.4% Cu or 0.4 g/t Au are shown in Table 1 below. More detailed mineralised intercepts are provided in Table 2.

The Winu exploration camp is located approximately 200 km by gravel and sand track from the Great Northern Highway. The camp is a seven hour drive from Port Hedland, which poses a significant safety risk. A gravel airstrip is being constructed at Winu for emergency response purposes. In addition, the sand section of the track will be upgraded for logistics supply purposes.

In conjunction with the ongoing work at Winu, RTX will continue to explore its adjacent wholly owned licences and joint venture licences within the Paterson Province.

The Winu project is located within the Exploration Licence E45/4833 which lies within both the Nyangumarta and Martu Native Title Determination areas. It is approximately 130 km north of the Telfer deposit in the Paterson Province of WA (Figure 1). An 80-person temporary exploration camp was constructed in stages throughout 2018.