Studying Ecological Approaches to Vegetating Old Mine Sites

Mine-tailings-with-stream-passing-through

Mine tailings with stream passing through

Green Solutions to Erosion and Mine Waste

The abandoned Nant y Mwyn lead mine lies in the valley of the Pen Cerrig Mwyn mountain and stretches to the banks of the Afon Tywi. In 1932 the mining company went bankrupt, leaving behind vast, steep-sided mounds of fine-grained and heavily polluted material.

The mine waste is too contaminated for anything to grow, and much of the site is bare.

With no vegetation to cover the soil and no roots to stabilise the surface the waste heaps are prone to severe erosion. As the tailings erode the material is deposited in rivers and pasture and causes significant contamination of the surrounding area.

TerrAffix have been working on a solution that is both cheap and effective and will vegetate mine sites such as Nant y Mwyn. The trials are being studied by Heather De-Quincey of Swansea University, who has a background in geochemistry.

Nant y Mwyn mine tailings and spoil heaps with the stream below

Nant y Mwyn mine tailings and spoil heaps with the stream below

Extensive Pollution Impacts from Orphaned Mines

The waste from Nant y Mwyn impacts upon 65 km of waterways and causes environmental standard failures for zinc, copper, lead and cadmium.

Most mine reclamation strategies involve using machinery to re-profile the landscape before capping the waste with geotextiles and clay.

However, for orphaned mines with no owner liability, the cost of this process is prohibitively expensive for the government bodies with whom the responsibility falls.

Research into Solutions

TerrAffix have been sponsoring Heather’s PhD, developing and testing a low-cost green-engineering solution to reduce the erosion and the spread of pollution without the need for hard engineering.

This involves hydroseeding a biochar-enhanced biochar enhanced, organic, growing medium created from sustainable natural materials and seeding with a diverse acid and metal-tolerant selection of grasses that mimic the native community.

Nant-y-Mwyn-mine-tailings-and-spoil-heaps-with-the-stream-below

Nant y Mwyn mine tailings and spoil heaps with the stream below

The vegetation, which is rapid, immediately reduces erosion, and long term these plants will facilitate nutrient cycling and soil formation, both essential processes which initiate ecosystem complexity.

Green Long Term Solutions

The on-going work is helping us develop cheaper and more effective reclamation strategies for mines which have previously been too expensive to remediate, ultimately providing a low-cost and accessible solution to land contamination and erosion reduction.

Heather De-Quincey