Unmarked tunnels, missing trackers, and fake doors have been uncovered during an initial investigation into the deadliest mining tragedy in China in over 15 years.

The government has vowed to leave no stone unturned, according to state media.

At least 82 people were killed by a gas explosion on Friday at the Liushenyu mine in Shanxi province.

Two remain unaccounted for with a further 128 hospitalized.

This incident is the deadliest mining accident since 2009 when an explosion at Xinxing Mine in Heilongjiang province resulted in 108 fatalities.

The cause of the recent explosion remains under investigation.

Concealed mining tunnels, falsified drawings, and outsourced miners without required life-saving location trackers are contributing factors to the tragedy.

The mine maintained two separate sets of plans and surveillance systems to manage official inspections while concealing operations from regulatory oversight.

This practice is colloquially known as 'yin-yang drawings.' Similar profit-driven tactics have been prevalent in coal mines across China despite crackdowns.

The Liushenyu mine used fake doors made from wire mesh and plastic sacks sprayed with mortar to evade detection during official visits.

To further avoid scrutiny, the mine operator hired subcontracted labor without equipping them with required trackers or logging their entry records.

This lack of accurate maps and location information has severely hampered rescue efforts.

The mine also deliberately avoided installing gas-monitoring equipment to circumvent authorities' supervision.

Authorities were aware of these issues prior to the tragedy, as the mine operator was fined in 2025 for concealed working faces.

Some mines across China have halted or reduced production following the incident for safety inspections.