(Reuters: Rio Tinto (NYSE) reduced its 2021 iron ores shipments forecast Friday due to a tighter Western Australian labour market. This delay caused the construction of a Gudai-Darri greenfield mine.

Now, the miner expects that 2021 Pilbara ironore shipments will range between 320million tonnes (mt), 325mt and 325mt. This is down from the previous lower range of 325mt to 334 mt.

Rio is now in danger of losing its position as the largest iron ore producer worldwide to Brazilian rival Vale S.A.

The company stated that a tight supply chain worldwide contributed to the problems.

Rio noted that “there are clear headwinds due to recent regulatory tightening in China” and warned of volatility.

Prices for iron ore have almost halved from a peak of record in May, as demand has been hurt by China’s reductions in steel production and the sharp decline in property activity in response to regulatory reforms.

Rio still shipped 83.4 million tonnes of steel-making commodities in the three-months ended September 30, which is 2% more than last year’s 82.1 mt.