Representatives from Rio and Baowu signed a heads of agreement to reinforce the partnership at a ceremony in Shanghai.
The Bao-HI JV has achieved sales of more than 180 million tonnes of iron ore since it was created in 2002.
The JV incorporates the Eastern Ranges mine, part of the 24 million tonne per annum Greater Paraburdoo operation.
The JV also covers the Western Range project, where a prefeasibility study is due to be completed by the end of next year.
"The signing of this agreement is a significant milestone in the partnership between Rio Tinto and Baowu that extends back more than four decades and was enhanced with the creation of the Bao-HI JV," Rio Tinto Iron Ore chief executive Chris Salisbury said.
"The success of this relationship has contributed to the growth of both our organisations over many years and is one which continues to develop and strengthen over time."
Baowu, created in 2016 via the consolidation of Baosteel Group Corporation and Wuhan Iron & Steel (Group) Corporation, is the world's second largest steel producer and Rio's largest Chinese customer.
Rio holds 54% of the JV with Baowu holding the balance.