Towards a Minerals Local Plan for Derbyshire and Derby

Towards a Strategy for Brick Clay and Fireclay

Appendix

Appendix

Mouselow Quarry

A clay and shale quarry, operated by Wienerberger UK, is located at Mouselow, near Glossop. The quarry has been operational for many years, at least since 1879, and historically there was a brick factory on the site.  Brick clay extraction is undertaken by the ‘campaign’ method; the material is stockpiled on site. The raw material is removed off-site to the customer which is Wienerberger UK’s Denton Brickworks, in east Manchester, some 10 miles away.

The quarry is primarily worked to extract shale for use in brick making. The shales are part of the Millstone Grit Group which consists of an interbedded sequence of shales, mudstones and sandstones. The upper most shales which remain in the knoll feature in the western part of the site are currently the main source of brick making material. Below the upper shales lies a 6 metre thick deposit of high sulphur shales which are not suitable for brick making as the sulphur content is higher than can be used in the Denton factory. Below the high sulphur shales there are further low sulphur shales suitable for brick making which currently form a minor amount of the extracted material from the site. These lower shales can only be extracted after the overlying high sulphur shales have been removed.

In addition a 4 to 8 metre thick bed of sandstone occurs between the upper shales and the high sulphur shales. This sandstone is also removed to allow extraction of the underlying shales. The sandstone is used as a high quality building stone with a minor amount, which is not suitable for use as building stone, being used as a construction aggregate.

As of the end of 2013 the reserves of shale and sandstone material within the current planning permission area were as follows[1]:

  • Upper shales – 354,600 tonnes (197,000 cubic metres)  
  • Sandstone – 10,800 tonnes (125,000 cubic metres)
  • Lower shales – 1,085,400 tonnes (603,000 cubic metres)
  • Total – 1,450,800 tonnes (806,000 cubic metres)

(Tonnage estimates based on using a conversion factor of 1.8 tonnes/cubic metre)

At the present time, extraction from Mouselow has been substantially reduced from the levels experienced in the 1990s due to the closure of Cheadle brickworks, which it also supplied, and reduced output of the Denton brickworks. Output of clay from Mouselow is currently around 45,000 tpa and is unlikely to increase in the immediate future. If the economy improves in the longer term output is anticipated to rise to approximately 54,000 tpa.

The proposed rate of extraction for the foreseeable future, from the beginning of 2014, as set out in the planning application was as follows9:

Upper shales – 39,600 tonnes (22,000 cubic metres) per year - 9 years reserves remaining.

Sandstone – 10,800 tonnes (6,000 cubic metres) per year - 21 years reserves.

Lower shales – 5,400 tonnes (3,000 cubic metres) per year currently, to be increased after all the upper shales have been exhausted in 9 years to 54,000 tonnes (30,000 cubic metres) per year -approximately 28 years reserves in total.

Based on this information the stockpiles and extensive permitted reserves at Mouselow would last well beyond the plan period. Planning permission was granted in December 2014 to vary a time limited planning condition on the site which extends the period of working from 2019 to 2042, enabling these reserves to be worked throughout the Plan period and beyond.

More recently, January 2015, the operator has submitted evidence indicating that, after recent trialling, because of the high carbon content, the lower shale reserves are not economic to use on their own without blending with the upper shale reserves. This greatly reduces the availability of suitable brick making reserves from the quarry. Based on a future average production of 45,000 tpa the quarry has only sufficient reserves of Upper Shales to last for approximately 9 years. (This calculation takes into account the use of a small quantity of Lower Shales for blending purposes).

To compensate for this loss of reserves the operator is promoting, through the local plan process, a small extension to the area of extraction within the permitted site, (as shown on the Map: Mouselow Quarry) which will generate a further 1,400,000 tonnes of Upper Shale. These additional reserves of high quality brick making shale will ensure the supply of material to Denton beyond the Plan period. Planning permission will be required to enable mineral to be extracted from this area.

The Denton brick factory is a substantial modern facility with the ability to produce over 50 million high quality bricks per year. Mouselow clay and shale makes up the largest proportion of brick making material used at the Denton plant, over 50% overall, and is used in most of the brick clay mixes; a total of 67 different product types are produced at Denton. The Mouselow material has good consistency, low sulphur, good potash and medium carbon levels in comparison with other clay sources. Mouselow clay and shale is essential for the continued operation of the brickworks.

 mouselow

 

[1] Planning Application CM1- 0214 -162 to vary conditions of planning permission R1/0310/24 to alter restoration landform and extend the end date for winning and working of minerals at Mouselow Quarry, Wienerberger Ltd, January 2014, Vol 2 Non Technical Summary