Wheal Jane

The Coal Authority, on behalf of DEFRA

Long term operation and maintenance of flag ship mine water treatment scheme

Truro, Cornwall

Location & Overview

The Coal Authority, on behalf of DEFRA and the Environment Agency, awarded the operation and maintenance contract for the Wheal Jane mine water treatment scheme near Truro, Cornwall, to John F Hunt Regeneration. The operation of the Mine Water Treatment Works runs for 5 years, with an option to extend further into the future. The Wheal Jane plant was built after a catastrophic release of contaminated water in 1992, a year after the mine was closed and its pumps turned off. A drainage tunnel, or adit, near the surface collapsed, and more than 45million litres of acidic mine water poured into the Carnon River and the Fal Estuary. This was the biggest water-related pollution incident in the UK and ranks highly among the world’s largest water pollution events.

Work, Challenges & Solutions

The Wheal Jane mine water treatment scheme treats mine water pumped from below ground using a high-density sludge process.
The resultant sludge is pumped into a dam, and the treated water is discharged into a stream. In a typical year, approximately 6,000,000 m3 of mine water is abstracted, 600 tonnes of metal contaminants (predominantly iron and zinc) are removed, and 2,000 tonnes of hydrated lime, 7,000 kg of anionic flocculant and 3,000 MW-h of power are consumed.
In addition to the operating plant, the plant infrastructure includes a workshop, storage facilities and office space.
John F Hunt ensure the effective and continuous operation, planned and preventative maintenance to the mine water treatment plant, by carrying out daily checks on the plant, taking samples and carrying out maintenance activities. The team make informed adjustments to the treatment process to ensure efficient use of chemicals and power, whilst procuring additives and supervising delivery.
Developing and implementing a 10-year management programme and maintaining an asset management system, ensures compliance with consents, licences, and permits.
Liaising with appropriate regulatory bodies and adhering to health, safety, and environmental standards is carried out daily as is reporting operational costs, safety statistics and performance trends.
John F Hunt provide and manage a database to capture and store plant data. They are periodically asked to manage capital projects, supervise and assist in research and development, cover flow monitoring and water sampling services in the southwest region and carry out emergency works when necessary.