Environment

Tunstead

Geology

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.

 

Restoration

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.  

BAP

 

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.

 

 

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.

Environment FAQs

Have you got a question on how the Tunstead site affects the environment? We have some helpful answers for you below.

If your question isn't here, contact us directly on tunstead.feedback@tarmac.com


Q. How do you ensure emissions are within limits?
We continuously monitor certain emission during our operational hours, these monitors are very precise and have to meet EU and UK quality and reliability standards as well as being calibrated by independent skilled third party. The data from the monitors is recorded in our control rooms where alarms will trigger if an emission is breached. Every 3 months we submit the daily data to our regulators to demonstrate compliance and all records are retained at the plant for at least 6 years to be reviewed if necessary. 

Other emission where technology does not allow continuous measurement an independent certified test house takes samples of our emissions and test them in a laboratory every 6 months to check levels are in compliance.

Q. Do you ever go over your limits? And if so, what happens?
Our Environmental Management System (EMS) sets out procedures to ensure we can comply with our limits and our operators and managers work very hard to ensure we do not go over the limit, however if we do then this is reported to the regulator in line with our permit and EMS. Investigations are carried out to understand why we went over the limit and corrective actions put in place to prevent this happening again.

Q. What comes out the chimney at Tunstead?
The main emissions from the Chimney are Carbon Dioxide and water vapour, this is the steam you sometimes see if the weather conditions allow, much like boiling a kettle in a cold or hot room. Other major emissions are Oxides of Nitrogen (NOx), Sulphur Dioxide (SOx), Carbon Monoxide (CO), Particulates (Dust) . NOx, SOx, CO and Dust are all continuously monitored against limit values to show they are at safe and acceptable levels. These limits along with other smaller emissions are listed in our permit along measurement requirements.

Q. Does using wastes as fuels change what comes out the chimney?
Using waste as a fuel does not have a negative impact upon the emissions from the chimney, many years of extensive measurements have shown there is no change and a study by the department of health independently verified this. In fact some fuels such as Tyres can help to reduce certain emissions such as NOx and other fuels have a bio mass content so they help us to lower our emissions of CO2.

Q. What happens to the quarry land after you’ve finished with it?
All of our quarries have restoration plans to develop them in line with local need at there end of their life. The final restoration is agreed with the local authorities and examples of former quarry restoration across the UK includes retail and commercial developments to nature reserves, outdoor classrooms and woodland walks. Read more about our restoration work above. It is important to note that not all restoration is carried out at the end of quarry operations, we are constantly conducting restoration work as areas of the quarry finished in order to reduce the operational footprint and visual impact of the quarry.

Q. What happens to wildlife on your site?
Before any work starts on a new quarry an environmental impact study is carried out to check for animals and flowers/grasses which need to be preserved or re located. Only once this is done the quarry will begin. During the quarry operation many animals choose to make their home in the quarry and live happily alongside our operations. Animals and birds often seen living in the quarry will range from rabbits, foxes, badgers and hares to swallows, swifts, bats, kestrels, owls and peregrine falcons. When these animals take up residency we work alongside them with respect and ensure any activity which may disturb them is not carried out during sensitive times such as when they have young.

Q. If someone has a concern, what should they do?

If you have any concerns you should contact us via email tunstead.feedback@tarmac.com

 

Sustainability and carbon reduction

Sustainability is at the core of Tarmac’s business and is deeply embedded in our culture. Our sustainability strategy plays a central role in our vision to becoming our customers’ preferred choice for sustainable construction solutions.

We have set ambitious commitments and targets based around four key themes - people, performance planet and solutions. The cement made at Tunstead and the range construction materials produced by Tarmac’s business, play a vital role in the construction industry.

The UK Government has set targets around carbon reduction and sustainability, which will change the built environment. As a leader in the UK construction sector, Tarmac is set to play its part.

Read more about Sustainability here

Primary Fuels and Alternative Raw Materials

The Mineral Product Association (MPA) Waste Code of Practice has now been implemented at Tunstead Cement Plant. In the past, when a new alternative or waste derived fuel was ready to be used in the plant, a full permit variation had to be submitted to the Environment Agency; this process was time consuming and costly. Going forward a variation will not be required for any of the fuels listed within the Waste Code of Practice. There are over 100 different pre-approved wastes listed in the code, and although not all of them will be appropriate for every kiln, it greatly increases our choices and ability to be innovative while decreasing the dependency on traditional fossil fuels.

Previously, a permit variation would have cost £30,000 and take approximately 6 months to be processed by the Environment Agency. Now that the MPA Waste Code of Practice has been implemented there is no additional cost required to vary the permit and wastes can be trialled on site following the completion of a risk assessment and notification to the EA.

Tarmac aims to increase its waste derived and alternative fuel usage to 70% by 2020, as outlined in the Sustainability Strategy. This will reduce carbon emissions, divert wastes away from landfill and ensure sustainability into the future by becoming less reliant on conventional fossil fuels.

In order to achieve these targets, the Tunstead Cement Plant has already trialled new waste materials in the pyro and grinding processes. For example, using slip casting moulds from the pottery industry as a substitute for gypsum in the Cement Mill, although this material has all of the chemical properties required for the end product, the size and shapes of the moulds were not suitable for the system at Tunstead. In some cases, the material has been used in other Cement Plants in the Tarmac network and has a very good track record; MBA Polymer is an example of this. MBA Polymer is a plastic granulate generated from the recycling of cars and consumer appliances, it has been used in Tarmac’s Aberthaw Cement Plant in South Wales successfully due to the process benefits it offers; it has a very high calorific value and therefore allows a high substitution rate in the kiln.

Tunstead Cement Plant has a target of 60% fossil fuel substitution rate for at least one month during 2016. Possible future fuels and alternative raw materials to help us achieve this include; tyre fluff from tyre recycling, waste clays from mineral extraction and catalysts from the petrochemical industry.