coal mining safety, internet of things solutions

Coal mining is one of the most dangerous professions, historically taking the lives of hundreds of thousands of coal miners. Although deaths in coal mines are at an all-time low, this industry still presents its workers with conditions that can have detrimental effects on their health.

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One of the main causes for concern is the production of toxic gases inside the underground tunnels of a mine, which is merely a by-product of the mines. Because of the health implications, the goal of many mining companies is to ensure that their workers do not encounter these gases and that the mines can be evacuated once they become very hazardous. ThingSpeak offers a robust Internet of Things (IoT) solution for integrating different sensors to detect dangerous scenarios.

Risks of coal extraction

When working in a mine there are many potential hazards, including thermal stress. Exposure to extreme heat and humidity can cause fatigue, heat stroke, and worsen other health conditions. Heat and humidity fluctuations are common in mines due to being underground with few channels for heat and hot air to escape.

Another common occupational hazard here is that of exposure to chemicals. Some of these chemicals are the ones that miners work with, while others are natural gases that come directly from the surrounding environment. Some of these more toxic gases are carbon monoxide, hydrogen sulfide and methane. Once inhaled, these gases can cause prolonged breathing problems, decreased oxygen flow, and in severe cases, death.

ThingSpeak: An Internet of Things analytics (IoT) platform.

ThingSpeak is an IoT analytics platform created to collect, analyze, and visualize data directly from multiple sensors via the Cloud. IoT platforms such as this have been created to allow the transmission of data over the Internet from multiple sources, utilizing technologies such as intelligent devices and cloud computing.

What makes ThingSpeak convenient for monitoring conditions within a mine is its ability to visualize and analyze different data streams in real time. With the increasing availability of cloud computing power and cost reduction, IoT solutions like ThingSpeak are providing reliable and cost-effective ways of continuously monitoring sensor data.

ThingSpeak can also be fine-tuned for specific domains. In the case of coal mines, this would mean the integration of algorithms that can determine the conditions inside the mine from the sensor data to then allow the signaling of those in the mine.

The new model of the IoT system

Composed of several parts, the SRM Institute of Science and Technology has proposed an IoT system to monitor conditions within coal mines.

As an overview of this system, there are various sensors that are integrated into a device known as NodeMCU. This device is then able to transmit and receive data from the ThingSpeak platform. There is a beacon and LED attached to the NodeMCU that acts as the main system to warn nearby miners of any danger.

The main system interface uses the Ardunio Integrated Development Environment (IDE), which is a low-cost IDE commonly used for robotic and hardware engineering projects. The Arduino IDE provides a keyboard for imputing commands on the system, while also providing a way to secure information coming from the system.

The central component of the system, NodeMCU, features an ESP8266 microchip that supports a WiFi module, allowing data to be transferred between the system and the cloud over the Internet. Connected to NodeMCU are a series of sensors that continuously take measurements of conditions within the mine. The first of these is the GHT-11 sensor, which is a sensor for temperature and humidity. Another is the MQ-6, which is a high-gas sensor that allows the detection of hydrogen, methane, alcohol vapors (which are highly flammable) and carbon monoxide.

Another gas sensor is also used in the system, the MQ-7 sensor which detects carbon monoxide and is required due to the highly toxic nature of the gas. In addition, light-dependent resistors ensure that the lighting conditions inside the mining tunnels are suitable and safe for operation.

A flame sensor is also used to detect the presence of any nearby fires.

The system will use all of these sensors to determine mine conditions. If any of these sensors transmit values ​​that are considered hazardous, the system will activate an alarm and an LED to alert those in the mine for imminent danger. Because the system is connected to the ThingSpeak platform, mine conditions can be monitored in real time in a country abroad, with those observing the readings being able to warn those who are mining through the platform.

The general system proposed here provides a cost-effective way to monitor conditions in a mine and also presents a way to collect data for long periods of time up to the second interval. Having such data provides a way for those responsible for mining safety to analyze and possibly predict how conditions may change in different areas of the mine, increasing the safety of those within the mines.

References and further reading

Prabhu, D. et al. (2019) IoT-based coal extraction safety for workers using Arduino. IJESC.

American Bureau of Labor Statistics. (2010) Injuries, diseases and deaths in the coal mining industry. [Online] Available at:

Brandon Gaille (2019) 26 Statistics, trends and analysis of the coal mining industry. [Online] Available at:

KaaIoT Technologies. What is an IoT platform? [Online] Available at:

ThingSpeak. [Online] Available at:

Dr. R. Bhuvaneswari. et al. (2021) Design of IOT-based coal mining safety monitoring and alarm system. Gazeta Paideuma.

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