Client
The Mining Remediation Authority formerly the Coal Authority, is an executive non-departmental public body, sponsored by the Department for Energy Security and Net Zero.
The organisation manages the effects of past coal mining. It deals with mine water pollution and other mining legacy issues.
It also owns, on behalf of the country, the majority of the coal in Britain. They provide services to other government departments and agencies, local governments and commercial partners, and contribute to the delivery of the UK Government’s Industrial Strategy and the environmental, social and economic priorities of the UK, Scottish and Welsh Governments.
Overview
Our team was appointed by the Mining Remediation Authority to upgrade the existing measurement structure at the outlet of the Minto MWTS, near Lochgelly in Fife. The objective was to provide accurate time-series measurement of discharge flows to ensure compliance with their discharge permit. The Minto MWTS scheme is a passive gravity-fed system that treats mine water via a series of reed beds.
Challenge
The existing outlet flume, located in a concrete chamber approximately 2.5m in diameter and 2.2m deep, was unsuitable for the current setup. The flow, entering through three 300mm pipes and into a 250mm wide approach channel, created turbulence and resulted in the flume being completely drowned. Additionally, challenges included:
- Determining suitable design flows of 8.72 l/s (minimum) and 98 l/s (maximum) from available site data.
- Selecting a primary structure that adhered to BS ISO standards and MCERTS relaxations.
- Addressing turbulence from the three incoming flows to ensure accurate flow measurement.
- Managing the upstream surcharge on reed beds, particularly during refurbishment periods.
- Mitigating debris and vegetation buildup within the chamber invert.
Solution
A thin plate weir was determined as the most suitable option based on design flows, available upstream head, modular limits, and measurement uncertainty. Key steps included:
- Designing and building a 400mm rectangular-notch weir integrated into a ‘tank’ structure to create an appropriate approach channel within the chamber.
- Installing baffle plates for flow straightening and additional upper and lower baffles upstream of the weir to mitigate turbulence.
- Ensuring the weir plate was removable to address upstream surcharge concerns during reed bed refurbishment.
- Producing detailed general layout drawings, manufacturing drawings, and design reports, including uncertainty tables and charts.
- Equipping the system with a level sensor, logging equipment, secondary pressure sensor, and a solar power system for operational efficiency. A gauge board was also included for visual checks of the flow depth from the top of the chamber to remove the need for entry and improve safety.
Client Benefits
- Accurate Flow Measurement: Enhanced time-series data aligned with BS ISO and MCERTS standards ensured compliance with discharge permits.
- Optimised System Design: The weir and baffling system minimised turbulence, providing reliable and precise measurements.
- Operational Flexibility: A removable weir plate allowed uninterrupted operations during reed bed refurbishment.
- Comprehensive Documentation: Detailed reports and uncertainty analyses provided transparency and confidence in system performance.
- Sustainable Operations: Solar-powered logging equipment supported environmentally friendly monitoring.
Client Testimonial
Cura Terrae were appointed to our Hydrometry framework and have successfully delivered several flow measurement installations. The sites at Minto, Kames and Chell Heath presented unique challenges due to existing infrastructure, but their team worked closely with us to develop practical, innovative solutions that met our requirements and were delivered to a high standard.”
Rob Burton BSc (Hons) MCIWEM CWEM Senior Hydrologist
