CMLR - Centre for Mined Land Rehabilitation

Centre for Mined Land Rehabilitation

Coal reject instead of soil? - Evaluation of coal rejects as an alternative to topsoil at the Curragh open-cut coal mine

The CMLR, in collaboration with environmental staff of Curragh Queensland Mining Ltd., have been investigating sustainability of rehabilitation using coal rejects as a surface mulch.

Monitoring has shown the successful establishment of native trees and shrubs in the absence of strong grass competition found on topsoiled areas. Over time, the weathering products of rejects have been absorbed by the underlying spoil, where they provide a number of benefits including increased Ca and Mg status and reduced Na. Lowering exchangeable Na is expected to improve aggregate stability and increase infiltration. pH reduction of often highly alkaline spoil materials also enhances nutrient availability.
Areas of concern are continued salt release from some rejects, and poorer water relations, contributing to lower than ground cover development.
Current research is focusing on the hydrochemistry of leachates from areas of stockpiled rejects.

For further information contact:
Mansour Edraki
m.edraki@uq.edu.au
(07) 3365 8552

© 2009 The University of Queensland, Brisbane, Australia
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Authorised by: CMLR
Maintained by: A. Pudmenzky
Last Updated: 19 June 2009