Mining in general, and particularly mining underground, can create potentially hazardous environments.  Whether it is from noise and vibration that can negatively impact on workers or lead to accelerated wear in plant and equipment, or air columns that contain particles or gases that can ignite or explode, there is always a need for quality vibration, noise, heat and expansion products that mitigate those risks.

All underground mining applications require fresh air to be pumped in and dirty air to be expelled.  The problem is that the air underground can become contaminated with potentially flammable particles such as coal dust, or gases such as methane.  An air flow moving over a metallic or hard plastic surface can generate static electricity, and the sudden grounding of that charge can lead to a spark, with catastrophic consequences.

Room for Expansion

This is where Pyrotek’s range of patented expansion joints come into their own. They are fabricated from a special material that is both conductive and has a low Ohm resistance enabling it to pass full mines certification and achieve a FRAS rating (Fire Resistance and Anti-Static).

By definition, expansion joints must be high-quality products and apart from mining applications, they are also used in industrial equipment, plant units, machinery and pipelines. They have been proving their worth for many years in power generation, HVAC, the waste disposal, cement and steel production, the chemicals industry, materials handling and the ceramics industry.

In addition to ventilation ducting, most exhaust gas duct work also requires expansion joints or vibration eliminators to absorb any movement in duct work as it expands and contracts under normal operating cycles.  Bellows can be designed to offer a specialised solution for the control of chemical expansion.


After years of experience in the mining industry, they are able to select the correct materials for any application, depending on operating temperature and the type of corrosive gases present.

The company also supplies fabric expansion joints made from high temperature fabrics and are also able to incorporate high density noise barrier materials to provide a sound barrier in joints on or near fans.

In addition to a range of standard expansion joints for the industry, Pyrotek’s engineers are able to inspect and assess an application, design and test a compliant product that is fit for purpose, then manufacture and install onsite as required.  This applies to both mobile and fixed plant. 

Pyrotek offers custom-made metallic bellows for high temperature, pressure and chemical resistance applications as well as high noise reduction acoustic expansion joints.  They feature fabric expansion joints custom designed and fabricated from a variety of specialty fabrics to withstand highly corrosive, acidic and alkaline conditions.

Custom-made fabric expansion joints.

Considerations on a Mine Site

Mine sites are bound by numerous OHS and environmental regulations that ensure the safety of their workers and the environment.  Of particular concern is mobile plant acoustics – whether it is the comfort of the operator or the welfare of neighbouring towns, noise control is paramount.  Mine sites that are proximal to housing or towns can be fined heavily if they breach noise caps during operation and these alarms can be triggered by as little as a change of wind direction if machinery is not adequately suppressed.

Exhaust systems must not only be covered to reduce the risk of fire from oil and fuel or burns to maintenance staff but also to dampen their noise emissions.  Pyrotek has developed a name in the mining and oil and gas industries for designing, manufacturing and installing high quality heat and acoustic covers for most common mobile mine equipment.  Given the company’s design capabilities, it is also able to custom-make covers for any application.

Equipment hire companies should consider this compliance requirement for all their plant destined for mining applications because they must be thermally and acoustically covered to be permitted on site.  Therefore, even if a machine is primarily rented out for civil engineering work, its exhaust system and turbochargers must be covered before it passes through a mine gate.

One additional criterion for mine approval is that exhaust covers are totally non-absorbent: that is, the covers will not absorb fuel or oil. On the contrary, with an outer layer made of PTFE (teflon) or silicone-coated fibreglass, any liquid simply beads and runs off the surface. Pyrotek actually goes one step further in its thermal blanket construction, adding another layer of PTFE under the outer layer, just in case the top surface is worn or cut at any stage. This added layer of protection provides both added protection and longer service life for the covers. To add strength, structural integrity and even longer life, Pyrotek’s covers feature an inner layer of knitted stainless steel mesh that sits directly against the hot face of the exhaust pipe.

Pyrotek’s thermal covers are fuel and oil repellent, highly effective at insulating hot exhaust plumbing and turbocharger housings. They not only significantly reduce the chance of fire but also protect personnel from burns and help reduce engine compartment temperatures to keep engine inlet temperatures down and improve the life of proximally mounted electronics. They are also widely used for cryogenic applications where pipes, tanks and valves need to be insulated from external ambient temperature.

An acoustic expansion joint.

Faster Fitment and Removal

The beauty of thermal blankets and exhaust covers is that they are easy to install, easy to remove during maintenance work and easy to refit. This translates directly to less labour hours required to complete a given job and therefore lower operating expenses.

Removal and replacement time savings of up to 70% are regularly achieved when compared to conventional steel heat shields.

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