HDS Treatment Trails

The Mining Remediation Authority (MRA) is undertaking this preliminary market engagement to better understand the availability of suppliers capable of delivering field-based High Density Sludge (HDS) pilot treatment trials for zinc bearing mine waters and to inform its procurement approach.

In particular, the MRA wishes to understand the extent of supplier capability and capacity within the market for these specialist services. The MRA is seeking to procure a specialist supplier to design, provide, mobilise, operate and report on containerised pilot-scale HDS treatment trials for metal-contaminated mine water at three sites: the former Threlkeld Lead Mines in Westmorland and Furness; Abbey Consols Mine in Ceredigion, Mid Wales; and a site within the Minsterley catchment, Shropshire. The trials are required to validate HDS treatment performance, establish optimised operating conditions and generate robust design, cost and operational data to inform potential full-scale mine water treatment schemes.

The requirement is for field-based HDS pilot trials suitable for zinc-rich mine waters with differing water chemistry. The Threlkeld trial will address net-acidic mine water with zinc as the primary contaminant and secondary metals including iron, aluminium, manganese, lead, cadmium, arsenic and nickel. The Abbey Consols trial will address circum-neutral pH mine water with zinc as the primary contaminant and secondary metals including iron, aluminium, manganese, lead, cadmium and nickel. The Minsterley trial will address zinc-rich circum-neutral mine water with lead and cadmium as key secondary contaminants. Flow conditions vary by site and the supplier will be expected to propose and operate an appropriate pilot configuration for each location, including suitable flow management, chemical dosing, monitoring and control arrangements.

The supplier will be required to provide and operate containerised HDS pilot plant and equipment capable of demonstrating removal of zinc and relevant secondary metals through appropriate precipitation, sludge recirculation and clarification processes. The trials shall determine optimum treatment conditions, including target operating pH, reagent selection and dosing approach, and may include aeration and/or carbon dioxide stripping capability where appropriate. The scope includes all activities necessary to plan, mobilise, operate, monitor, demobilise and report on the trials. This includes, but is not limited to, pilot plant design and configuration; supply of plant, equipment, chemicals and consumables; mobilisation and set-up; commissioning; operation of the pilot trials; sampling and analysis; process monitoring; solids handling; retention of representative sludge samples; provision of sludge material for WM3 classification and characterisation; data management; interpretation of results; and preparation of final technical reports.

The supplier must provide all necessary health, safety and environmental documentation and controls, including method statements, task and site-specific risk assessments, CoSHH assessments, safe systems of work, emergency procedures, PPE requirements and an environmental management plan. Elements of site security (CCTV, fencing) may also be required by the MRA. The trials are expected to be delivered under the Construction (Design and Management) Regulations 2015. The supplier will be required to comply with all applicable UK health, safety and environmental legislation and to work in accordance with the MRA's site access, stakeholder, environmental and operational requirements.

Participation requirements are expected to include proven experience delivering HDS trials for metal-contaminated mine water, demonstrated experience in the treatment of zinc-bearing, net-acidic and/or circumneutral mine waters as applicable to the sites, and evidence of operating and optimising field-based pilot HDS trials. Suppliers must be able to demonstrate relevant technical capability, suitable field delivery experience, robust health and safety management, and the ability to produce high-quality trial data and recommendations for full-scale treatment design.

The key deliverables will include trial operation records and datasets; detailed testing methodology; performance assessments; optimised operating parameters; sludge characterisation samples and supporting information; and final reports containing conclusions and recommendations for full-scale treatment. The final outputs must provide sufficient evidence to support treatment process validation, full-scale design development, capital and operating cost estimation and future decision-making by the MRA.

The estimated value for each trial is expected to be in the range of £150,000 to £200,000 ex VAT. The anticipated duration of each trial is approximately six weeks, requirements currently expected to be delivered by 31 March 2027. The MRA may procure one or more of the site-specific trials under the same opportunity. The MRA may also procure more sites in the future under this notice.