What in the world is happening with China and ASX 200 mining stocks?

S&P/ASX 200 Index (ASX: XJO) mining stocks have been on a rollercoaster over the past month, with due credit to China for the wild ride.

In late morning trade today, the big Aussie iron ore miners are all trading in the green.

Fortescue Ltd (ASX: FMG) (ASX: FMG) shares are up 2.0%; BHP Group Ltd (ASX: BHP) shares are up 0.3%; and Rio Tinto Ltd (ASX: RIO) shares are up 0.8%.

For some context, the ASX 200 is up 0.2% at this same time.

The miners look to be benefiting from the 1.5% uptick in the iron ore price, which is currently trading for US$106 per tonne.

As for that rollercoaster ride, it was only back in late September that iron ore dipped below US$90 per tonne.

But following some significant stimulus measures from China's government to help spur growth and boost the nation's struggling property sector, the iron ore price marched steadily higher.

Last Tuesday, the steel-making metal hit US$114 amid investor expectations China would announce another round of outsized stimulus measures. Instead, last week's National Development and Reform Commission (NDRC) meeting failed to detail any major new plans.

The iron ore price immediately retreated on the news, and ASX 200 mining stocks hit the downhill side of that rollercoaster ride.

Despite significant losses last week, however, all three of the big iron ore miners remain well in the green over the past full month.

As of 17 September:

• The BHP share price is up 10.2%
• The Rio Tinto share price is up 8.9%
• The Fortescue share price is up 15.2%

Here's what's happening now.

Will ASX 200 mining stocks get more support from China?

Over the weekend, China held a much-watched briefing on its evolving plans to ensure the economy hits the government's 5% growth target.

But investors in ASX 200 mining stocks were likely hoping to hear more detailed and stronger support measures from finance minister Lan Fo'an. Instead, he said further details could be expected over the coming weeks. He added that local governments could use special bonds to buy unsold homes and promised major support to ease the debts carried by those local governments.

But many experts believe that won't be enough for China to reach its growth target.

According to Jacqueline Rong, chief China economist at BNP Paribas (quoted by Bloomberg):

The policy to support consumption sounds quite weak. It is still too early to call an imminent significant turnaround in deflationary pressure or a bottoming-out of the property market, which are the two key issues faced by the Chinese economy.

Bloomberg economists Chang Shu and David Qu added:

With no immediate new money in sight, central policymakers are likely to focus on supporting local governments to deliver their budgeted spending, while making use of existing resources to stabilise the housing market.

And Lynn Song, chief economist for Greater China at ING Bank, indicated that investors in ASX 200 mining stocks may need to be a bit patient to see China's growth engine shift into higher gear.

"My sense is that the fiscal policy moves will take a little too long to roll out for us to hit 5% this year unless the ultimate scale of fiscal stimulus ends up being much larger than forecast," Song said.

Stay tuned!