Mine Tailings Capping and Drainage

Pozidrain SKL and Erosaweb, Carrshield  Mine Works, UK

Project Information

Client:Defra, The Environment Agency & The Coal Authority
Contractor:J N Bentley
Consultant:Golder Associates
Product:Pozidrain 4SKL Geocomposite
Erosaweb GWX100/300 Geocell
Quantity7,000m2 Pozidrain
2,100,0m2 Erosaweb
Benefits:- All-in-one drainage & capping system
- High flow capacity in both directions
- Integral overlaps for ease of install without specialist installation tools
- Large roll widths for rapid installation
- Material cost savings
- 120 years design life for long term assurance


Project Description

The former Barneycraig lead mine at Carrshield is located within the North Pennines Area of Outstanding Natural Beauty, which itself is a UNESCO Global Geopark.

The mine operated primarily between c.1760-1920, and the mine tailings were deposited along the east bank of the River West Allen during that time. As a result, the river was the joint second worst in the Northumbria River Basin Management Plan in respect of mine water pollution, contributing around 20% of the total quantities of lead, zinc and cadmium found in the Tyne Estuary, over 40km downstream of the site.

The site was prioritised for remedial action as part of Defra’s Water and Abandoned Metal Mines programme, in partnership with the Coal Authority and the Environment Agency.

The Challenge

As part of the action plan for the site, the tailings storage facility required a permanent capping solution to prevent rainwater infiltration into the tailings, thus achieving the two key objectives for this part of the works, which were;

  • To afford long term stability to the tailings dam, which had already begun to collapse into the River West Allen in several places;

  • To mitigate the creation, and subsequent ingress, of an estimated 3,500kg of leached lead, zinc and cadmium into the river each year.

The Solution

The original capping solution for this site included a separate flexible membrane liner (FML) and a geocomposite drainage layer (GDL). ABG simplified this by proposing Pozidrain 4SKL, which provides both functions in a rapidly installed single layer without compromising the integrity of the containment. ABG Pozidrain geocomposite requires no specialist contractors or equipment to install.

By using Pozidrain 4SKL geosomposite drainage capping solution, the contractor saved significant material costs compared to purchasing separate FML and GDL layers, as well as reducing the programme time for the installation works, whilst still fulfilling the key objectives of the project.

Erosaweb GWX geocell was used on the 1:2.5 slopes to reinforce the soil veneer, and a fixing solution was used that secured the Erosaweb geocell panels without puncturing the new cap.

ABG Pozidrain 4SKL Drainage Geocomposite for mine tailings capping and drainage

ABG Pozidrain 4SKL Drainage Geocomposite

The ABG Service

ABG provided design assistance, including slope stability and flow capacity calculations.

Contact ABG today to discuss your capping, drainage and slope reinforcement project specific requirements and discover how ABG’s experience and innovative products can help on your project.

Installation of ABG Pozidrain geocomposite capping layer for mine tailingsWide width rolls enabled rapid installation and minimised the number of joints
Erosaweb geocell panels providing soil veneer reinforcementErosaweb geocell panels providing soil veneer reinforcement
Flat selvedge for rapid overlapping and jointing of the geosyntheticFlat selvedge for rapid overlapping and jointing
Slope reinforcement using ABG Erosaweb soil veneer geocellsSlope reinforcement using ABG Erosaweb soil veneer geocells


Erosaweb Geocell

Erosaweb geocell is designed for the reinforcement of weak soils and has many applications including retention of soils on steep slopes and highway and rail embankments. The cells of the geocell retain the fill material, while allowing water through.

more...

Erosaweb Geocell is a cellular confinement system

Pozidrain

Pozidrain drainage geocomposite is a wide-width preformed drainage and gas venting solution, providing a sustainable, environmental alternative to traditional filter stone drainage layers. Used extensively for landfill and contaminated land drainage on slopes and basal areas to remove water, liquids and gas quickly & efficiently.

more...

Pozidrain Drainage geocomposite for landfill drainage and capping from ABG Geosynthetics
 

Products

Erosaweb Geocell

Erosaweb geocell is designed for the reinforcement of weak soils and has many applications including retention of soils on steep slopes and highway and rail embankments. The cells of the geocell retain the fill material, while allowing water through.

more...

Erosaweb Geocell is a cellular confinement system

Pozidrain

Pozidrain drainage geocomposite is a wide-width preformed drainage and gas venting solution, providing a sustainable, environmental alternative to traditional filter stone drainage layers. Used extensively for landfill and contaminated land drainage on slopes and basal areas to remove water, liquids and gas quickly & efficiently.

more...

Pozidrain Drainage geocomposite for landfill drainage and capping from ABG Geosynthetics
 

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