Evaluation of mining lagoon silt as a suitable medium for restoring land to arable conditions

CENTA2 is a consortium of research intensive Universities and research institutes that are working together to provide excellence in doctoral research training. Cranfield University is proud to be working alongside these partners to create the next generation of scientific leaders in environmental science. The student will be based at the Cranfield campus at Cranfield in Bedfordshire. https://www.cranfield.ac.uk/About/How-to-find-Cranfield

Overview

During sand and gravel extraction, washing and scrubbing are part of the processes which removes fine particles. Water which is used in this process with suspended silt is pumped into lagoons. Over time silt can accumulate in these lagoons. Currently the use for such silt has not been fully explored when it is excavated periodically, being seen as a by-product. Mineral operators such as Tarmac typically have agreements for an after care period of 5 years to return the land back as close as possible to its original state after aggregate extractions. The challenge being faced by Tarmac and other mineral operators is the lack of restoration medium especially for subsoil during the aftercare period. This project, developed in close collaboration with Tarmac, proposes to conduct a study in Yorkshire, Nottinghamshire and Hampshire to evaluate the quality of silt coming from these lagoons as a replacement media for subsoil.

Aim
: To evaluate physical, chemical and biological parameters of silt that will influence its successful re-use as subsoil media in restoration of mining sites to arable land

Objective 1 : Assessment of characteristics of silt from lagoons as suitable subsoil medium

This objective will entail design and implementation of a strategic sampling program to facilitate visits to Marfield (Yorkshire), Lockington (Nottinghamshire) and Blashford (Hampshire) Quarries. Representative silt lagoon samples will be collected to assess their quality in terms of bulk density, shear strength, porosity, pH and organic matter as indices of silts suitability for providing nutrients for crop establishment. Information on the potential quantity of silt that can be excavated from lagoons to determine the supply of material that can meet the demand for subsoil in restoration sites will be collated. There will be laboratory analyses to determine a range of suitable physical, chemical and biological characteristics that will form the basis of an assessment of biotic and abiotic barriers to crop growth.

Objective 2 : Assessment of biotic and abiotic barriers to effective agricultural restoration using silt from lagoons

The characteristics mentioned in Objective 1 will determine the suitability of this medium as a potential subsoil that is susceptible to minimal compaction and also facilitate drainage in restoration sites. A pot study and field trial will be carried out to verify this. Cranfield University’s repository on the Land Information System (LandIS) (www.landis.org.uk) will be used to match the properties of silt from the lagoons to silty sub-soils (and associated crop suitability, drainage, compaction risk assessments) in order to enable the suitability of this material in restoration sites to be assessed.

For full project description please visit: http://www.centa.org.uk/themes/climate-environmental-sustainability/c9/

Key dates
• Application deadline – 21st January 2019
• Interviews (to be conducted via Skype) – w/c 11th February 2019
• Selection panel – 21st February 2019
• Universal acceptance date – 20th March 2019

How to apply -
To apply for one of the Cranfield University projects you will need to complete our online application form.

1. Please state the name of the project you will to apply for
2. When asked how you intend to fund your postgraduate studies please state that you wish to apply for a NERC CENTA2 studentship.
3. You will also be required to complete and submit the CENTA2 studentship application form and attach it to the application form.