Annesley Pithead after abandonment. The water was brought to the surface at 27C.
Introduction.
The issues surrounding minewater in the UK are many and various: they pollute rivers and streams with a variety of metals, change their acidity, threaten and in the past have polluted aquifers. Minewaters are generally a problem that has focused the minds of many consultants and academics for years and will continue to do so.
The Coal Authority is funding the running of 75 minewater treatment schemes from Cornwall to Fife, with still several hundred treatment schemes to be put in place. More still are expected to be needed but their locations have not as yet been identified. Costs are a critical factor with identifying ways to decontaminate minewater using less land area, cower cost methods and income generating possibilities that might use aspects of the water as a resource. The traditional methodologies employed are often large and expensive to run: active treatment works often require chemical flocculants, lime dosing or other multi stage treatments. Other minewaters are more readily treated using passive treatments such as lagooning and wetland treatments.
The expense of active or passive treatment systems vary greatly with active methods needing automated dosing and other systems plus buildings and connections to utilities, they also need active management: passive systems may require large land area to be taken on to locate reedbeds, lagoons and utilities including electricity supplies for pumps and other uses. They also need management: though not on a day to day basis.
The location of sites for any remedial work are escalating year on year with many of those sites that have already been put in place been installed on lands inherited by the Coal Authority from British Coal in 1994. The need now is to identify sites that might offer returns to the Coal Authority that might be used to cover the costs of remediation and ideally produce income so as to help fund further works.
One income generating scheme: that of using minewater as an energy resource is at long last starting to be considered in the UK. The use of low grade heat to be developed by heat engines of whatever sort and the resultant hot water used both for heating and hot water supply domestic or industrial premises. The same technology can be also used to deliver cooling in the form of air conditioning and chilling of specific infrastructure such as data banks.
Procurement.
The need to work with providers to act not just as suppliers but partners within such projects. It may be that partnerships are developed rather than just putting out to tender.
Players.
The sections below briefly outline the roles that need to be filled to make a project both viable and work, the main stays are all reasonably obvious but the last in the list is pivotal as without such a body the scheme will not happen.
Land owner
The landholder or landholders need to see their land be both a crock of gold or at the least offer a return on investment and simultaneously they need to feel that something special is to happen on it.
Coal Authority.
The body that holds many of the keys to any minewater project as it is in their shafts and workings that the target water is to be accessed, though the water belongs to the state. Their engagement is crucial as their agreement or not can stop a project in its tracks. Some small projects have been carried through to completion without it (Glasgow and in Fife) but that will not happen again.
Developer.
The company that plans to put bricks and mortar or at least tin and steel industrial units on the site. They are important but often unversed in the concepts employed and will find it a difficult to comprehend: so needing explanations so as to grasp the benefits and engage their involvement.
Local Authority.
The local authority planners are vital in that they can say no or at least recommend to the planning committee that planning permission should be refused. A well thought through plan that demonstrates sustainable concepts and worked through with the local authority planning officer to fit with planning agendas will though seldom fail.
Technology Provider.
The answer to getting the heat transferred from the minewater to the water networks needs to be carefully chosen. There are several companies about, but most are not aware of the easily fallen into traps. Any oxygen in the water during heat transfer and the whole process clogs up, in minutes or days. Aggressive water needs to be catered for with components that will not be worn out in months.
The provider needs to be engaged with the project so as to be part of the scheme and not an add-on chosen purely by tender.
Infrastructure provider.
The nuts and bolts of transferring the heat from source to customer either as heat or hot water needs to be engaged as soon as possible, even before
Environment Agency, SEPA or NRW.
These agencies are often in a secondary role as they need to see abandoned minewater treated. They will set consents of quality for the treated water to be discharged into a receiving water. Their early involvement though is a must.
Funder.
There are funders who work closely with technology supply or infrastructure providers and are often keen to be involved to see if there are extra values that might be extracted from any scheme.
Heat networks are easy and cost effective to install within a new build scheme but when it is intended to fit heat networks to existing properties the price rises substantially but still makes economic and environmental sense.
Customers.
A project such as this needs customers to make use of the heat procured. Ideally there will be one or more major user of the base load. Households or office heating are not the ideal as there are major fluctuations in need for heat and hot water or cooling so a user of constant supply is a driver to economic surety for the long term success of the scheme.
Liaison and coordination.
This is an all important role, often not linked to any of the above parties and that independence is vital. They drive the project forward and have no ideological reliance on any one party in alliance.
They need to take a broad brush approach to the scheme but also able to grasp vital detail. The history and technologies that are available and is capable of bringing this diverse knowledge base to the table. One of their key rolls is to maintain the impetus and direction of the whole group of participants.
Note.
Since 1992 Clean Rivers Trust has been an active proponent of the use of minewater as a resource in all its aspects: water resource, both as a potable or process water for industry, the use of the minewaters heat which can range from 12C to 30C or more for commercial and residential uses. It has looked at energy storage within the flooded voids of mines with the concept being published for the Selby Coalfield in 2006 where waste heat from traditional power generating complexes close to the set of mines that makeup the coalfield such as Eggborough and Drax might be brought up to a viable steam generating condition for electrical power generation. The Trust has researched the use of mineshafts for hydroelectric turbines or hydraulic rams in the 1990s at the time of maximum mine closure.
The Trust is constantly revisiting new and old technologies to develop the future use of facilities based around mines and mining, opera