Simon McGarry, senior equity analyst at Canaccord Wealth Management, was also bullish on Rio.
He highlighted that CEO Sam Walsh, who took over in 2013, had focused on larger assets, while "zealously" pursuing better spending decisions and cost cutting, with several projects that had previously been approved now shelved.
"The combination of economies of scale, falling production costs and stronger balance sheet should allow Rio to weather any slump in prices until the supply and demand imbalance is resolved which may take two years according to S&P," he said in a note.
Read MoreWhy commodity giants need to think like manufacturers
And while volatile trading for BHP and its spin-off were likely for the rest of the week , Credit Suisse analyst Paul McTaggart said that things would like stabilize in the longer term.
By the end of 2016, BHP's debt is set to be trimmed to flat, he said, meaning that the group's dividend should be safe. He also highlighted that although the newly formed group is not a "production growth" story, its plans to be a low-cost, high-return and low-capital-expenditure miner mean he expects a strong recovery in underlying earnings.