Towards a Minerals Local Plan for Derbyshire and Derby

Towards a Strategy for Industrial Limestone

Introduction

  1. Introduction

1.1     Limestone

          Limestone is often described as the world’s most versatile mineral. In terms of the number of quarries and the scale of tonnage produced (around 10 million tonnes annually in recent years - average annual production 2007-2013[1]) it is by far the most significant mineral quarried within the Plan area.

          Limestone is mainly quarried for use in the construction industry where its physical properties have made it the principal source of crushed rock aggregate for use as fill material, road stone and in the manufacture of concrete. A separate strategy paper has been produced on the working of Limestone for aggregate uses.

          Limestone is also a very important ‘industrial’ mineral where its chemical properties make it a valuable mineral for a wide range of industrial and manufacturing processes; recently[2] around 3 million tonnes has been quarried annually in the Plan area for this purpose. This strategy paper is about ‘industrial limestone’. More detailed information can be found in the following supporting papers:

 

Industrial Limestone Supporting Paper – February 2015

 

Cement Supporting Paper – February 2015

 

 

          Limestone is also used on a very small scale along with sandstone as building stone. The availability of local stone to conserve the character of the Plan area’s historic built environment is of great local importance. Separate strategy and supporting papers have been produced on the working of Limestone for building stone.

 

Towards a Strategy for Building Stone – November 2014

 

Building Stone Supporting Paper – November 2014

 

 

 

1.2     Industrial limestone

          End uses

          Industrial limestone is important for a wide range of downstream manufacturing industries. It can be used as a raw material, for example, in cement manufacture and flue gas desulphurisation or it can be burnt (calcined) to produce lime and used in iron and steel making or in the chemical industry. It can also be ground to make a fine white powder which is used extensively as filler in a diverse range of products such as paints, plastics, paper, rubber, sealants, toothpaste etc. Unlike aggregate limestone, some industrial limestones are sold in the global market making the resource economically very valuable.  

 

          Specification

          Industrial limestones are valued mainly for their chemical properties, however, for many uses it is the level, or absence, of specific impurities present or the consistency or colour of the limestone i.e. a combination of chemical and physical properties that are important. These properties can make the performance of a specific industrial mineral quite different from one deposit to another.  Consequently, individual deposits may be aimed at particular products or markets and, as a result some specifications for products or markets are written around individual deposits.

1.3     Mineral resources

          Although limestones occur widely in England, many are unsuitable for industrial use because of their chemical and/or physical properties.  Within the Plan area, the three main areas of Industrial Limestone production are the Buxton and Wirksworth areas of the Carboniferous Limestone, bordering the Peak District National Park, and the Permian Limestone area around Whitwell in the east of the county.

1.4     Method of Working/Processing/Transportation/Restoration

          Industrial limestone is predominantly worked from surface quarries. The potential for the quality of the mineral extracted from a single site may vary considerably. This may require multiple extraction faces within one quarry, or supplies of specific feedstock from several different quarries, to enable blending of lower specification material with that of a higher grade.  Alternatively, it may result in only a small proportion being suitable for specific industrial end uses, with remaining minerals being used for alternative purposes such as aggregates. In view of the relative limited occurrence of ‘industrial’ limestone, it is important to make the best use of the resource, including minimising the use of this material for aggregate purposes.

          The price of an industrial limestone product is largely governed by the cost of extraction, processing and transportation. The processing plants associated with industrial minerals are generally large and require high capital investment, particularly for cement and lime manufacture.  This has led to the development of large quarries that can produce large outputs over long periods of time.  Limestone (both for industrial and aggregate purposes) is currently the only mineral quarried within the Plan area where the scale of working has made it cost effective to transport the mineral product to market by rail, for example, from Tunstead Quarry, Dowlow Quarry and Dove Holes Quarry.

          The scale of limestone quarries and the often relatively small quantities of waste material generated compared to the rock taken out means that it is not generally possible to restore land to its original levels following completion of working. Final restoration depends to a large extent on the depth of the quarry and level of the water table.  Natural regeneration incorporating water is usually appropriate for deep quarries and, in such cases, they can become important areas for wildlife and natural history. In cases where the depth is not too great, the quarry floor can be restored for agriculture or informal leisure uses.

1.5     Demand/production and reserves

          The annual production of industrial limestone from the Plan area has remained fairly steady at around 3 million tonnes over the last 5 years[3]. If demand follows the national trend [4] production is not expected to increase significantly over the Plan period. At the end of 2013, the Plan area had total estimated permitted reserves (at active and inactive sites[5]) of some 228[6] million tonnes of industrial limestone, equivalent to over 75 years of production at current rates.

          In 2013, a total of nine quarries produced industrial limestone within the Plan area, as shown on the accompanying map. Most of these quarries also produced limestone for aggregate use and in some cases industrial limestone production is quite low. Permitted reserves at active sites for industrial uses totalled some 197[7] million tonnes. In addition to the active quarries, a further five inactive quarries have reserves of industrial limestone (in total around 31 million tonnes[8]), and would not require a new planning permission to resume extraction, but are not currently producing limestone.

 2015 06 01 Limestone resources (2)

[1] East Midlands Regional Aggregates Working Party Reports (2007-2013)

[2] East Midlands Regional Aggregates Working Party Reports (2007-2013)

[3] EMRAWP Annual Reports 2009-2013

[4] UK Minerals Forum:Trends in UK Production of Minerals Jan 2014 – 7.8 Industrial Carbonates

[5] Active sites are those in current production and inactive sites are those with planning permission where production could readily commence. Sites that have been officially classed as ‘dormant’ are not included because that permitted reserve cannot be exploited until new planning conditions have been agreed, paragraph 3.3 EMAWP Report 2013.

[6] EMAWP Annual Report 2013

[7] EMAWP Annual Report 2013

[8] EMAWP Annual Report 2013