The limestone quarry in Tunstead owes its location to major geological changes that took place over 300 million years ago when the area was covered by a warm, shallow sea. During the Carboniferous period, the water levels dropped and millions of shells and marine organism skeletons were left behind; the Carboniferous limestone that is quarried today was formed from these deposits.
The limestone is an extremely pure source of calcium carbonate which is used in many different manufacturing processes.
There are two main types of limestone at Tunstead- the high purity Chee Tor stone and Woo Dale stone which is less pure and used for construction purposes.
The Tunstead Quarry lies within Derbyshire immediately adjacent to the boundary of the Peak District National Park. However, much of the remainder of the site, including the majority of Old Moor Quarry lies within the Peak District National Park.
Progressive restoration has been underway throughout recent quarry development operations. Biodiversity management projects have been implemented as part of a Biodiversity Management Plan since 2007.
In June 2014, we conducted a review to outline the extent to which progressive restoration and biodiversity management initiatives undertaken at Tunstead and Old Moor Quarries have had a beneficial effect on the natural environment of the locality.
For all of the areas identified in this review, the habitat types developed through progressive restoration provide direct or indirect support for habitat conservation targets set out within the Peak District National Park Biodiversity Action Plan.
In addition, a number of species conservation targets identified by the Peak District National Park also benefit from the effect of progressive restoration and biodiversity management at Tunstead and Old Moor Quarries.
Waste derived fuels
Waste-derived fuels can be a range of things and waste tyres are used as a partial replacement for fossil fuels in the cement-making process. Solid Recovered Fuel (SRF) for example, is a specially prepared blend of non-hazardous materials, which would normally be land-filled, used as a fuel for the cement-making process.
In June 2014 Tunstead Cement Plant commissioned a Selective Non-Catalytic Reduction (SNCR) which uses ammonia solution to reduce NOx emissions from the Kiln stack.
The benefits of reducing the NOx emissions are:
- It will have a positive effect on health and the environment.
- Improved clinker quality.
- Increased flexibility of the kiln to enable demonstration of longer term improvements in the kiln stability.
- Demonstration of decreased energy consumption per tonne of clinker produced.
- It will enable the Company to remain competitive by keeping energy costs under control, thus securing hundreds of local jobs.
- It will enable reduction of emissions of the greenhouse gas carbon dioxide from fossil fuels.
The use of SNCR to reduce NOx emissions is well established across the majority of the other cement works in the UK and Europe, so is not novel in the cement industry. In addition to this, the SNCR system meets the Best Available Techniques (BAT) requirements of the Industrial Emissions Directive (IED) defined by the BAT Reference Document for the Production of Cement, Lime and Magnesium Oxide.
Waste code of practice for cement kilns
In March 2014, following detailed consultation with the cement industry, the environmental regulators responsible for monitoring and controlling the use of waste derived fuels in the UK - Scottish Environment Protection Agency, Environment Agency, Natural Resources Wales, and Northern Ireland Environment Agency - introduced a new Code of Practice governing the way waste is used in cement kilns.
The new Code of Practice works by identifying and ‘pre-approving’ a list of 101 waste types that can be used in cement kilns as non-fossil fuels or waste-derived fuels. Prior to March 2014, consultation on the use of new waste fuels was conducted on a fuel by fuel basis.
The changes will make it easier to use waste from a range of approved sources so that companies are able to move more quickly to take advantage of a variety of pre-approved waste fuel sources as they become available.
These changes are very important because they will help us further reduce our use of fossil fuels, which, in turn, will cut carbon emissions and divert more waste away from landfill.
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