The Australian Securities Exchange had mixed leads today but chose to follow North American stocks down.

The S&P/ASX 200 closed 1.6% or 68.8 points down to 4144.9, after swinging between an intraday high of 4203.2 and a low of 4135.4.

Basic materials fell 3%.

Newcrest Mining was a major casualty, slumping 6.4% or $A2.30 to $33.45 after reporting lower quarterly gold production.

BHP Billiton dropped 2.5% or 92c to $35.48 and Rio Tinto fell 3.4% or $2.23 to $62.85 amid continued fears over iron ore demand from China.

However, UBS believes the headlines over Vale selling iron ore at spot prices instead of contract prices are exaggerated.

“What it has been asked by clients in China and is willing to accommodate, is a move to provisional pricing,” UBS said.

“The effect of this is to remove the quarter lag on spot vs contract.”

UBS noted Vale was more vulnerable than the Australian iron ore miners due to the longer lead times on deliveries.

Fellow iron ore producer Fortescue Metals Group fell 4.6% or 21c to $4.31.

Copper-gold miner OZ Minerals fell 5.4% or 63c to $10.98 as analysts adjusted their ratings for the miner following yesterday’s quarterly results.

Macquarie rated OZ as “outperform” with a 12-month price target of $14.40.

“We believe OZ is well positioned to generate strong near-term cashflows and continue to pursue its regional and near mine exploration program to extend the base-case [life-of-mine],” Macquarie said.

At UBS, analysts took a very different view, downgrading the stock from buy to neutral.

“With a limited mine life at Prominent Hill and in our view, a significant number of technical challenges to overcome on the Carrapateena project, we believe OZ provides little in the way of volume growth for investors,” UBS said.

“Subsequently, future growth needs to come from the drill bit or from value-adding [mergers and acquisitions] – both of which can be problematic to predict.”

Meanwhile, Lynas Corporation bucked the trend today, gaining 3.2% or 3.5c to $1.125 after diving nearly 10% yesterday.