Balancing mine safety with efficiency using nitrogen 

Oxair Gas Systems Chief Engineer David Cheeseman explains why nitrogen is not just vital to the mining industry but also how the latest innovations are cutting onsite costs and improving safety still further. 

The coal mining industry is a lot more technology-focused than it used to be with advancements in autonomous underground mining and automated surface vehicles. However, it’s still very labor intensive, so reducing human exposure to risks like fires, lightning strikes, exploding tires on trucks and other potentially dangerous situations is a focal point for the industry.  

Underground nitrogen generation 

In terms of reducing the risk of fire, introducing nitrogen to the environment is an effective way to minimize this, since it expels oxygen, smothers coal oxidization and will suppress a fire in the worst-case scenario. But even this is not without risk, or indeed a price tag. Looking for ways to reduce the cost and hassle involved with the traditional method of drilling down holes from the surface to the seam for the supply of nitrogen, mine operators are now turning to underground nitrogen generators.  

Nitrogen generated underground at the coal face can be a highly cost-effective solution. The generators can often be rented and have minimal ongoing operational costs since they only need compressed air to provide the supply of nitrogen. Saving many kilometers of underground pipeline, the machines can be simply moved to wherever the gas is needed. An underground nitrogen generator significantly reduces the large infrastructure outlay of drilling boreholes.   

Well maintained nitrogen generating units are considered very safe for mines. Before being commissioned the machine must pass a risk management system, legislative compliance certifications and site compliant checks. Scheduled maintenance and regular inspections for possible leaks are carried out on nitrogen generators. The equipment also has ventilation and gas detection devices that control the risk of persons entering a confined space that may contain N2 gas. 

Maintaining tires on heavy machinery 

Nitrogen also plays an important role in mining when it comes to site vehicles. Nitrogen-filled tires protect mine workers by preventing fires when ruptured – an extra tier of safety on large off-highway trucks where the huge wheels are right underneath the driver’s position. They run cooler in extreme temperatures and remain inflated for longer. Unlike compressed air, nitrogen is an inert gas that does not react with other materials, so it’s resistant to corrosion.  

The International Council on Mining & Metals’ (ICMM) innovation for the cleaner, safer vehicles (ICSV) initiative – a supply chain collaboration with original equipment manufacturers – is to be commended. However, in the meantime rugged terrain will still be taking its toll on the tires of mining vehicles, the workhorses of the extraction process.  

Balancing efficiency with safe practice 

Maintaining a regular supply of nitrogen can be challenging for mines, which are often based in remote locations. Again, this is prompting many mining companies to turn to onsite generators, so they are not left reliant on the supply chain for nitrogen cylinders in extreme locations, where delivery is costly. With this equipment in place, mines can keep on operating and can accommodate fluctuating production schedules without unnecessary delay.  

The costs associated with setting up onsite nitrogen generation equipment are just a drop in the ocean when compared with payback that can be achieved many times over in the longer term. A nitrogen generator provides self-sufficiency as well as cost benefits and allows mines to turn supplies on and off as and when required.  

It is clear that with responsible mining practices geared up for long-term sustainability, investments in quality equipment are key to achieving both safety and efficiency goals. On-site nitrogen generators, which can be rented as and when needed, are providing mines with a fuss-free solution to site safety that is cost-effective and reliable, even in harsh environments. Nitrogen membrane systems are safe, reliable, easy to operate and never run out of gas, ensuring mines can focus on their core business of generating product and profits.  

By David Cheeseman   

David Cheeseman is Chief Engineer at Oxair Gas Systems, a world-leading manufacturer of gas process systems for shipboard and land-based use. Each of its systems focuses on reliability, safety and ease of maintenance.