Company & Application

STRABAG UK’s tunnelling project, based in North Yorkshire, UK, is being constructing as the world’s longest conveyor tunnel, known as the Mineral Transport System, as part of the Woodsmith mine development. This project will see transportation of tens of millions of tonnes of Polyhalite, a naturally occurring mineral substance and subsequently when crushed, POLY4, a multi-nutrient fertiliser used worldwide.

The project began launching a Tunnel Boring Machine to commence a 36.7km long tunnel, which was constructed using a single shield machine. This length of tunnel is expected to be a new world record with the tunnel fit out, including a new full length conveyor system.

The Challenge

The project demonstrates the scale of the tunnelling and underground construction capabilities in the UK, also highlighting the need for focus on innovation and social responsibility throughout all processes. The 380 m-deep shafts were constructed using the blind-bore method, not only with the aim of reducing carbon emissions, but also to improve general on-site safety. Extensive air quality monitoring was required throughout the entire project and, notably, Trolex systems were fitted to ensure reliable and accurate monitoring is available and maintained throughout the entire project.

The Trolex plan

A range of Trolex real-time solutions have been identified for use in the STRABAG project for the detection of hazardous gases and dusts in this tunnelling project. 236 devices, including SENTRO 8 Gas detector, SENTRO single Gas detectors and AIR X real-time Particulate Monitors have been fitted across multiple systems with a total of 824 individual sensors for both gas detection and dust monitoring.

As well as particulate ranges from PM2.5 to PM10 being constantly monitored, logic systems constantly watch for key gases such as CH₄, CO, NO, H₂S, SO₂ and O₂. Local emergency Audio/Visual alarms, Trolex Flow Sensors and Intrinsically Safe Battery Back-Up units have been added to back up the system and add intelligent data to the data all powered by intrinsically safe battery back-up units.

The Trolex solution

Alongside the systems being implemented across the tunnelling project, the Tunnel Boring Machine itself has also been fitted with multiple gas detectors, as well as Audio/Visual alarms and sensors.

Due to the nature of tunnelling projects, with fast paced demolition, excavation and drilling processes, cutting, concrete spraying and transportation generates fine dust and particulates as a by-product of natural materials like rock and sand being disturbed, increasing risk of lung diseases and respirable health issues.

The recognised risk of using combustion engines and diesel-powered equipment often produces carbon monoxide and Diesel Particulate Matter is something the project was increasingly aware of, something the system will flag through data indicators across its broad range of sensors.

Gas sensors are already actively working as the mining machine hits pockets of hydrocarbons which set the unit into alarm, and where necessary lower down the mining machine to avoid risk of explosion.

What it meant moving forward

Providing this pioneering safety technology to STRABAG meant the project has joined a long-standing reputation of safety instrumentation being supplied to workers by Trolex in some of the most challenging environments over the last 65 years.

Like many other underground industry leaders across the globe, STRABAG made the decision to deploy multiple Trolex detectors, monitoring equipment, sensors and alarms demonstrating to their workers that health and safety is a priority on this project, and a superior approach, not only for producing the highest quality throughout the tunnelling project, but also with a conscious effort on the effects relating to the workforce wellbeing and the wider society.