The Rio Tinto Limited (ASX: RIO) share price is set to finish lower today.
Despite the company not releasing any price-sensitive announcements to the ASX, the mining giant's shares are currently down 4.94% to $106.19.
This brings its losses this week to more than 8% following a broader market sell-off.
In contrast, the S&P/ASX 200 Index (ASX: XJO) is currently shedding 2.25%.
What's dragging Rio Tinto lower?
There are a couple of reasons as to why the Rio Tinto share price might be heading south today.
The current decline in iron ore prices is providing a resistance across the mining sector, with the majors down.
Shares in BHP Group Ltd (ASX: BHP) and Fortescue Metals Group Limited (ASX: FMG) are down 3.91% and 4.69%, respectively.
This is leading the S&P/ASX 200 Resources Index (ASX: XJR) to completely erase yesterday's 0.56% short-lived gain.
As such, the benchmark index for Australian resource companies is falling 3.34% to 5,475.2 points.
With the price of the steel-making ingredient fetching a three-week low of US$131.50 per tonne, investors have turned elsewhere.
The only performing index among a sea of red is the S&P/ASX All Ordinaries Gold (ASX: XGD) sub-industry.
The index is up 2.48% to 6,119.6 points.
Also putting pressure on the Rio Tinto share price is news surrounding China's plans to set up a centralised iron ore buyer.
According to the Financial Times, the Xi administration is hoping to reduce reliance on Australia's biggest export.
The move involves Beijing securing lower iron ore prices through larger bulk purchases from its state-owned mining and steel companies.
Notably, this will promote domestic iron ore production and boost investments in bringing mines online inside and outside the country.
Regarded as a key commodity in Rio Tinto's portfolio, the latest news is particularly significant.
In the financial year ending 31 December 2021, iron ore accounted for 62% of the total group sales revenue.
Rio Tinto share price review
Over the last 12 months, the Rio Tinto share price has dropped 14%.
However, when looking at 2022, the mining outfit's shares are up around 6%.
Based on today's price, Rio Tinto commands a market capitalisation of roughly $41.19 billion.
