News: RIO UPDATE 1-China January iron ore imports rise on pre-holiday restocking

• Jan iron ore imports hit highest since Sept -customs data
• Mills rushed to restock ahead of Lunar New Year holiday
• Ore supply expected to tighten after Vale accident in Brazil

(Adds detail, background)

BEIJING, Feb 14 (Reuters) - China's iron ore imports in January climbed 5.3 percent from December, customs data showed, supported by strong restocking demand at steel mills ahead of the week-long Lunar New Year holiday this month.

Shipments of the steelmaking raw material last month were 91.26 million tonnes, up from 86.65 million tonnes in December, but were still shy of 100.3 million tonnes in the same period last year, data from the General Administration of Customs showed on Thursday.

January arrivals were at the highest level since September last year.

Steel mills in China typically replenish their inventories ahead of the Lunar New Year holiday, which fell during the week of Feb. 4 this year, to ensure they have sufficient raw materials for at least 20 days.

Steelmakers also bought more iron ore last month to take advantage of rising profit-margins for steel, which climbed more than 40 percent in January.

Ore imports in February are likely to drop due to mills reducing their operations until downstream users return to work later this month after the holiday.

Vessel-tracking and port data compiled by Refinitiv suggests China will import about 79.35 million tonnes of seaborne iron ore in February, a pullback from 93.12 million in January due to the holiday disruption.

Iron ore supply is expected to tighten after the accident at Vale SA VALE3.SA 's mine in Brazil as regulators close sites. The collapse of a dam holding mine waste on Jan. 25, the second fatal collapse in the country in five years, killed 300 people.

As much as 70 million tonnes of high-quality iron ore fines and pellets from Vale could be affected, according to analysts from Jinrui Futures, Huatai Futures and Jefferies.

Brazil is China's second-largest iron ore supplier after Australia, accounting for 23 percent of the country's total iron ore imports in 2018.

The most-active iron ore contract for May delivery on the Dalian Commodity Exchange DCIOcv1 has increased 16 percent since Vale's accident and reached a record of 652 yuan ($96.35) a tonne on Monday.

($1 = 6.7673 Chinese yuan renminbi)