China's coal supply squeeze is set to persist as safety inspections expand from private mines to state-owned producers, extending a period of tightened supply that has pushed prices to multi-month highs since a deadly gas explosion in Shanxi in May.

The May 22 blast at a Tongzhou Group mine in Qinyuan county, Changzhi city, Shanxi province, killed 82 people and injured 128, with two still missing — the country's deadliest coal mining accident in two decades.

In the immediate aftermath, Shanxi authorities ordered mines to halt production for safety checks, with the toughest measures concentrated in central-southern Shanxi. The crackdown later spread to neighbouring Shaanxi and Inner Mongolia, and went nationwide following an emergency notice from the National Mine Safety Administration.

Coal output fell sharply as a result. National raw coal production dropped 9.7% year on year in June, with the decline widening by 8 percentage points from May, while output fell 4.11% month on month against a 3.01% rise in May. July saw the annual decline widen to 10.1%, with month-on-month output down 9.9%.

Shanxi showed signs of accelerating mine restarts around August. A July 25 meeting of city mayors stressed the need to push forward with safety inspections and production resumption on a mine-by-mine basis while cracking down on illegal production, and to orderly expand approved capacity.

However, a gas outburst at Yangmeishan coal mine in Lianyuan, Hunan province, on August 14 killed seven people, prompting fresh safety inspections across the province and casting a shadow over national coal production.

Supply tightness has shown no sign of easing, with strong pithead sales, low mine inventories and negative freight economics continuing to push coal prices higher to fresh multi-month peaks.

While earlier accidents and policy responses mainly affected private mines, a new document — issued by the National Mine Safety Administration on August 27 — is set to tighten safety constraints on state-owned coal companies.

The document, numbered 84, strengthens safety management at state mines across nine areas, including elevating safety inspection responsibility, normalising inspections and setting production targets. Unlike the short-term special inspections and rectification campaigns seen since the May 22 accident, Document 84 extends regulatory oversight to state enterprises, which account for a far larger share of supply.

State-owned coal companies are the backbone of China's coal supply stability. Data from the China National Coal Association shows the top 10 reporting large enterprises accounted for 49.3% of national raw coal output in January-July. Central state-owned enterprises supply over 25% of the country's coal, while state-owned producers overall account for more than 70% of output.

Under the new rules, inspections shift from periodic campaigns to institutionalised, higher-frequency checks within companies. Group companies must conduct at least one inspection covering all coal-related subsidiaries every six months, with sampling of no less than 20% of mines under each subsidiary. Production must be subordinated to safety, with output targets set based on mining conditions and disaster control capabilities.

Unlike previous safety notices issued during supply assurance periods, Document 84 places safety ahead of production, signalling that the intensified inspection measures introduced since the May 22 accident may evolve from periodic campaigns into permanent constraints. With the document's implementation, safety inspections are likely to exert more sustained pressure on coal production, potentially reducing medium-term supply elasticity further.