‘One-Click Replacement’ Swaps Real Sensor Data

Recently, inspectors from the National Mine Safety Supervision Bureau in Guizhou uncovered a highly technical and covert method of data falsification at a coal mine in their jurisdiction, exposing the mine’s deliberate disguise and effectively combating illegal activities to maintain mine safety.

At 23:46 on the same day, a gas exceedance alarm was triggered at the 1905 fully mechanized mining face of the Xintian Coal Mine in Bijie City, Guizhou Province, with a maximum value of 53.64%.

The Xintian Coal Mine is owned by Yonggui Energy Development Co., Ltd., a state-owned coal mine with an approved production capacity of 1.2 million tons per year, classified as a coal and gas outburst mine.

Upon receiving the gas exceedance alarm, the Guizhou Bureau immediately formed an investigation team in conjunction with the Bijie City Energy Bureau and the Qianxi City Energy Bureau to investigate the mine and conduct a simultaneous mobile inspection.

Thorough Investigation Reveals Clues

After more than an hour’s drive, the investigation team arrived at the mine and immediately began their work.

Through on-site investigation, the team confirmed the installation locations of the methane sensors at the 1905 fully mechanized mining face. The T3 sensor in the track lane was installed 8 meters away from the working face in the intake airflow, while the T1 and T2 sensors were suspended on the downwind side of the same airflow, at distances of 168 meters and 510 meters from the T3 sensor, respectively.

By overlaying and correlating the monitoring curves of the T3, T1, and T2 sensors, the investigation team found that at 23:46, the T3 sensor triggered an exceedance alarm; at 0:17 the next day, the T1 sensor triggered an exceedance alarm; and at 0:18, the T2 sensor triggered an exceedance alarm. The time intervals between the alarms of the T1 and T2 sensors and the T3 sensor were 31 minutes and 50 seconds and 32 minutes and 18 seconds, respectively.

“Under normal circumstances, the T1 sensor should trigger an exceedance alarm 2 minutes after the T3 sensor. However, in reality, there was a nearly 32-minute delay before the alarm was triggered for T1, and T2 also had a delay of over 32 minutes, which does not conform to the alarm pattern.” By calculating the airflow speed at the fully mechanized mining face and the distance between the T3 and T1 sensors, the investigation team quickly discovered the anomaly.

At 0:17:50, the T1 sensor’s gas monitoring value suddenly rose from 0.17% to 4.64%, while the T2 sensor’s gas monitoring value rose to 2.31%. This abnormal situation drew the investigation team’s high attention.

Simultaneously, by reviewing the monitoring video of the T1 sensor at the 1905 fully mechanized mining face, the investigation team found that starting from 23:20 on August 8, the alarm light of the T1 sensor had been flashing continuously. The monitoring system’s terminal interface showed that the gas monitoring value of the T1 sensor was around 0.2%.

Tracing Back to Uncover the Truth

The flashing alarm light of the sensor indicates either a sensor malfunction or a gas exceedance alarm.

Upon reviewing the monitoring video, the investigation team found that on July 22 and 23 of this year, the T1 sensor’s alarm light also flashed, but the monitoring system’s terminal interface did not show an exceedance alarm for the T1 sensor, further confirming the data falsification behavior of the T1 sensor.

“We must get to the bottom of this!” To clarify how the coal mine committed fraud, the Guizhou Bureau invited experts and equipment manufacturers to assist in the investigation, ultimately determining that the flashing alarm light in the monitoring video of the T1 sensor was indeed due to a gas exceedance.

“We used the ‘one-click replacement’ function to replace the data uploaded by the T1 and T2 sensors at the 1905 fully mechanized mining face with data from sensors in the return air duct with lower gas concentrations, without uploading the real gas data from that working face.” Faced with the investigation team’s thorough probing, the mine’s chief engineer ultimately admitted to this significant safety hazard.

Further investigation revealed that after the T3 sensor’s gas monitoring value reached 53.64% on August 8, the mine was concerned that the T1 and T2 sensors would not show an exceedance alarm, which could lead to detection by the mine safety supervision department. Under the chief engineer’s instructions, the monitoring center director used the ‘one-click replacement’ function at 0:17:43 on August 9 to switch the real monitoring data of the T1 and T2 sensors back to upload.

“Thus, at 0:17:50 on August 9, the gas monitoring value of the T1 sensor suddenly rose from 0.17% to 4.64%,” said the mine’s chief engineer.

To prevent the mine safety supervision department from discovering the data falsification by reviewing the operation log records of the coal mine monitoring system terminal, the monitoring center director logged in with the administrator account in the office to use the ‘one-click replacement’ function to switch the data, and then remotely accessed the monitoring system’s main database to delete the operation log data of the ‘one-click replacement’ on that day, resulting in no anomalies being found when querying the operation logs at the monitoring system terminal.

To eliminate evidence, on August 9, the monitoring center director arranged for underground monitoring maintenance personnel to remove their personnel positioning identification cards in the permanent refuge chamber and go to the intersection of the return air duct at the 1905 bottom extraction lane and the northern wing return air lane to dismantle the two sensors used for replacement, placing them in the permanent refuge chamber.

The mine uses the KJ823X mine safety monitoring system from a company in Nanjing. The ‘one-click replacement’ is a built-in feature of this system that allows seamless switching of data from sensors connected to the same substation.

At this point, the truth was revealed. The mine deliberately falsified the monitoring data by using two methane sensors installed at the intersection of the return air duct at the 1905 bottom extraction lane and the northern wing return air lane to replace the monitoring data of the T1 and T2 sensors at the 1905 fully mechanized mining face, causing the return air gas monitoring data of that working face to not reflect the true situation, while production continued.

Comprehensive Inspection to Prevent Falsification

“This method of falsification is highly technical and covert. Generally, it is difficult for regulatory inspectors to detect. This serves as a wake-up call for us; combating illegal activities in mines is a long-term task!” said the head of the investigation team.

To comprehensively eliminate related issues, the Guizhou Bureau quickly conducted inspections and statistics on all coal mines using the KJ823X mine safety monitoring system in the province, effectively strengthening data technical identification, strictly investigating monitoring system falsification behaviors, and fundamentally enhancing the ability to detect data falsification.

“This significant safety hazard exposes the weak safety awareness of some coal mines and the erroneous development view of ‘prioritizing production over safety,’” stated the head of the investigation team.

Currently, the Guizhou Bureau has legally ordered the Xintian Coal Mine to suspend production for rectification and has initiated a case investigation into the related issues. Meanwhile, individuals involved in the suspected data falsification have been legally transferred to public security authorities for investigation.