Lynas Rare Earths Ltd (ASX: LYC), Regis Resources Ltd (ASX: RRL) and Rio Tinto Ltd (ASX: RIO) shares are making waves today.
Two of the big Aussie miners are outperforming the 0.4% loss posted by the S&P/ASX 200 Index (ASX: XJO) in late morning trade, while one is trailing those losses.
Here's what's grabbing investor interest on Tuesday.
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Rio Tinto shares increasing copper exposure
Rio Tinto shares have given back their earlier intraday gains to be down 0.1% at time of writing, changing hands for $172.31 apiece.
Still, the ASX 200 mining giant remains within around 1% of its all-time highs as investors mull over the company's first quarter production results (Q1 2026).
Highlights for the three months included a 13% year-on-year increase in Pilbara iron ore production to 78.8 million tonnes. Iron ore sales increased by 2%.
Rio Tinto shares have also been steadily increasing their exposure to copper amid strong global demand and price growth for the red metal. Over the March quarter, the miner produced 229,000 tonnes of copper, up 9% from Q1 2025.
Rio Tinto CEO Simon Trott noted:
Operating excellence drove 9% YoY copper equivalent production growth across our portfolio as the Oyu Tolgoi copper mine continues to ramp up as planned and our integrated aluminium business, again, delivered a strong performance.
Management reaffirmed Rio's full year 2026 production and cost guidance for its core operating divisions.
Regis Resources shares gain on $198 million cash build
Regis Resources shares are also grabbing headlines today following the release of the gold miner's own quarterly update (Q3 FY 2026).
Shares in the ASX 200 gold stock are up 1.4% at $7.79 apiece after the company reported gold production of 90,600 ounces in Q3. That brings Regis Resources gold production for the first three quarters of the financial year to 277,500 ounces.
Investors will also have noted that Regis Resources added $198 million to its cash and bullion holdings over the quarter. As at 31 March, the gold miner has a cash and bullion balance of $1.13 billion.
With no disruptions to its fuel supplies yet from the Middle East conflict, the ASX 200 gold stock's full year FY 2026 gold production is in the range of 350,000 ounces to 380,000 ounces.
Which brings us to…
Lynas shares slip despite revenue boost
Atop of Regis Resources and Rio Tinto shares, investors are also talking about Lynas shares today after the ASX 200 rare earths miner reported on its March quarterly results.
Lynas shares are down 2.3% at time of writing, trading for $19.93 apiece. That fall comes despite a strong operational quarter, with market expectations clearly running high following the stock's 123% share price gains over the past 12 months.
As for the March quarter, Lynas reported gross sales revenue of $265 million. That's up 115% year-on-year and marks the highest quarterly sales revenue since 2022.
Management credited a 25% increase in the average Neodymium-Praseodymium (NdPr) selling price and increased rare earth sales for the revenue boost.
