TOKYO (Reuters) - Tohoku Electric Power (>> Tohoku Electric Power Co., Inc.) has agreed an annual thermal-coal import deal at prices 17 percent lower than a year ago with Rio Tinto (>> Rio Tinto Limited) (>> Rio Tinto plc), after not coming to terms with longtime supplier Glencore (>> Glencore PLC), the Nikkei newspaper said on Friday.

The move surprised traders and buyers and left them wondering whether the agreement would be considered the benchmark Australian coal price for Japanese utilities as had been the case with Tohoku's and Glencore's dealings. Australia is by far the biggest thermal coal supplier to Japan.

Global mining giant Rio Tinto and Tohoku Electric settled on a price in the upper $67 range per tonne for coal from Australia for the fiscal year beginning April 1, around 50 percent below the peak of $130 hit in fiscal 2011, the Nikkei said.

A Tohoku spokesman confirmed an agreement has been reached with a resource major other than Glencore, but declined to comment on other details of the contract. He would not say whether the company expected the deal to become the benchmark.

A trader and a buyer contacted by Reuters said they had heard indirectly that the price was set at $67.80 a tonne.

Tohoku had been negotiating prices with Glencore, the world's biggest thermal coal exporter, but the two sides have not come to terms so far this year, the paper said, saying Rio Tinto may handle the price talks going forward.

"We were really surprised that Tohoku signed the first deal with Rio, instead of Glencore," a Japanese trader who declined to be named said.

"We assume this was because Glencore kept asking for prices above $70," he said.

Buyers also said they were disappointed by the price as spot prices have plunged to below $60 a tonne recently.

Asian benchmark thermal coal from Australia's Newcastle terminal has fallen nearly 10 percent this year, last settling at $56.85 a tonne. The price has lost more than 60 percent since early 2011.

"The agreed price came a bit too high, but I guess Tohoku was obliged to accept it in order to secure a stable source of high-quality coal," another buyer said.

In past years, coal contracted annually by Japan - about 60 million tonnes - typically settled at around a $7-per-tonne premium to spot prices.

(Reporting by Yuka Obayashi; Editing by Himani Sarkar and Tom Hogue)