Thermal coal futures in China surged to a record high as a severe supply crunch overpowered the exchange’s effort to cool down the breakneck price rally.

Prices have rallied 34 per cent so far this year as miners struggle to meet robust demand from the nation’s economic rebound. Safety and environmental inspections, mining accidents and an unofficial ban on Australia coal has disrupted supply and tightened the market. A recent worsening in diplomatic relations with Australia has also given the raw material another boost.

Futures reversed a drop earlier Tuesday morning after authorities raised trading fees, typically a step that’s taken to cool markets. Trading fees for iron ore futures were also increased on Tuesday.

“The market has been unusually explosive,” said Huatai Futures Ltd. analyst Wang Haitao. Inspections in major coal-producing regions have been rife with corruption investigations in Inner Mongolia, overproduction probes in Shaanxi province, and environmental checks in Shanxi province. At the same time, power producers are stocking up on coal ahead of summer, when warmer weather boosts demand for air conditioning.

“In the near future, thermal coal will still see a mismatch between supply and demand,” said Wang. “As temperatures continue to rise, peak electricity consumption has not yet unleashed their true influence.”

Thermal coal futures on the Zhengzhou Commodity Exchange closed at 900.2 yuan ($140)a ton, surpassing the 900 yuan mark for the first time.

Several price providers have stopped releasing assessments, citing volatility. Fengkuang Coal Logistics said it will temporarily not release prices to avoid participants misreading the market. Separately, the China Coal Transportation and Distribution Association also said it will halt its price assessment report to help stabilize the market.