Brazil's Vale SA, the world's largest iron ore exporter, said it had to temporarily halt operations at the Viga concentration plant that is part of its newly-acquired Ferrous Resources do Brasil due to a permit problem, impacting some 330,000 tonnes of iron ore production a month.
But it said the suspension would not affect the Viga mine and that the permit issue was not related to a tailings dam.
The most-traded iron ore contract on the Dalian Commodity Exchange, with a January 2020 expiry, rose as much as 1.2% to 633.50 yuan ($90.00) a tonne, before ending the morning session at 627.50 yuan, up 0.2%.
A deadly tailings dam collapse at Vale's iron ore mine in Brumadinho in January prompted mine closures for safety checks in Brazil, disrupting supply and pushing spot prices of ores for delivery to No. 1 steelmaker China to five-year peaks.
Iron ore prices have pulled back in recent weeks amid signs that the supply crunch is easing, with Brazil's ore shipments to China having risen recently, but some analysts said the market will remain tight to some extent.
"There is still some structural market tightness," said Richard Lu, senior analyst at metals consultancy CRU Group's Beijing office.
"There is some (Vale) capacity not coming back soon ... although we think the tightness in supply in the second half is not going to be as severe as what we saw earlier," he said.
Lu also said iron ore "might be a little oversold" and that some corrections were expected after "very strong declines".
FUNDAMENTALS
* Benchmark spot 62% iron ore for delivery to China <SH-CCN-IRNOR62> was steady at $91.50 a tonne on Thursday, having rebounded from its lowest in more than four months, hit early this week.
* In the Singapore Exchange, the most-active September 2019 iron ore futures contract was up 0.4% at $86.76 a tonne in late morning trade.
* Chinese steel futures extended their rallies amid hopes Beijing would roll out more measures to stimulate the slowing domestic economy.
* The construction steel rebar benchmark on the Shanghai Futures Exchange ended the morning session up 0.5% at 3,720 yuan a tonne. Hot-rolled coil steel for car and home appliances manufacturing gained 0.7% to 3,737 yuan.
* Other steelmaking materials were also firmer, with Dalian coking coal up 0.3% at 1,328 yuan a tonne and coke edging 0.2% higher at 1,981 yuan.