Aggregates extraction


Marine aggregate extractionMarine aggregates production in Britain involves a fleet of some 35 vessels working full time and approximately 2500 people working both at sea and on land to produce approximately 22 million tonnes p.a. Current projections of the demand for marine aggregates show that the trend remains upwards and is likely to continue to increase until secondary use of building material for a variety of applications becomes more widespread.

The Crown Estate owns the mineral rights to the sea bed around the UK and issues licences for extraction. A royalty is paid to Crown Estate for every tonne of aggregate dredged and the Crown Estate will only issue a licence if permission is granted by the a Government View (GV) procedure, National Assembly for Wales (NAW) or the Scottish Executive (SE) and satisfactory environmental appraisals have been completed.

Although the programme is in the process of being reviewed, the aggregate producers have supported research in the past, into key areas of environmental concern through the Aggregates Sustainability Levy Fund, co-ordinated by DEFRANatural England and English Heritage.

PML research which has potential application to the aggregates sector are:

  • Benthic community characterization to e.g. investigate the impacts of extraction and potential for different management approaches to enhance recovery
  • Evaluation of goods and services provided by benthic communities associated with aggregates extraction areas
  • Social and economic analysis as a basis to provide improved understanding of progress towards sustainability
  • Evaluation of the interaction of aggregate extraction of other users of the marine environment (e.g. fishing, offshore windfarms) on ecosystem sustainability.

An example of a recent project

Predictive framework for assessing recoverability of marine benthic communities following cessation of aggregate dredging.

The purpose of this study will be to provide (for the first time) a predictive framework for the rate of restoration of species composition and subsequent recovery of biomass following growth of the individuals in marine deposits prior to dredging or other anthropogenic disturbance.

The study will therefore represent a significant advance on current approaches to the assessment of 'recovery' of biological resources which are entirely based on descriptive assessment following cessation of dredging at particular dredge sites. This will be the first study to integrate analysis of population dynamics and growth data into the widely-used multivariate analysis of community composition used in benthic studies in UK waters.