Client:
Anglo American
Location:
North Yorkshire, UK
Build time:
2018 - present
Woodsmith Project
STRABAG UK is constructing the world’s longest conveyor tunnel, known as the mineral transport system (MTS), as part of the Woodsmith mine development.
The mineral transport system will transport tens of millions of tonnes of polyhalite, which will be mined from beneath the North York Moors National Park.
Polyhalite is a naturally occurring mineral substance that, when crushed and granulated, creates POLY4, a unique multi-nutrient fertiliser suitable for organic farming. It will be used in worldwide fertiliser programmes to help boost crop yields and plant strength and improve soil structure.
STRABAG UK began construction works in May 2018 and launched the tunnel boring machine, named Stella Rose, in June 2019.
The project scope consists of:
- 36.7km-long, 4.8m internal diameter segmentally lined tunnel, constructed using a single shield, hard-rock tunnel boring machine.
- Two 380m-deep, 3.2m internal diameter intermediate shafts, which were constructed using the innovative blind bore method.
- The tunnel fit-out, including the conveyor system.
The tunnel length surpassed 25.8km in October 2023, becoming the world’s longest tunnel using a single tunnel boring machine. Once completed, the tunnel will be 36.7km long, which is expected to be a new world record.
Innovation
The STRABAG UK team on the Woodsmith project has developed innovative technology to introduce robotics and automation into the tunnel segment manufacturing processes.
The 380m-deep shafts were constructed using the blind-bore method, which resulted in a reduction of carbon by approximately 60% when compared to traditional shaft sinking techniques. It also improved safety, increased efficiency, and reduced costs.
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Environmental and social responsibility
As the polyhalite deposit is located under the North York Moors National Park, extensive measures have been taken to minimise the environmental impact on the natural surroundings.
To reduce any visual impact, mineshaft headframes have been sunk below ground, and any above-ground buildings have been designed to look like agricultural barns with wood cladding. Further environmental considerations include strictly controlled working hours for surface operations to limit light impact, the implementation of full noise control measures, extensive air quality monitoring, and the preservation of wildlife and ecology habitats.
The mined ore is transported from the Woodsmith mine near Whitby to the Mineral Handling Facility located in Teesside, where it is processed and shipped. By using a 37km underground conveyor belt system to transport the ore, there is minimal congestion on local roads and rail infrastructure, thereby reducing the impact on local communities.