Rapid seed-to-pot screening to inform alternative growth media development for coal mine rehabilitation

Authors: Robertson, LM; Levett, A; Laverick, B; Lyngcoln, S; Berghofer, P Download Paper Open access courtesy of:

DOI https://doi.org/10.36487/ACG_repo/2615_69

Cite As:
Robertson, LM, Levett, A, Laverick, B, Lyngcoln, S & Berghofer, P 2026, 'Rapid seed-to-pot screening to inform alternative growth media development for coal mine rehabilitation', in AB Fourie, G Boggs, J Heyes & M Tibbett (eds), Mine Closure 2026: Proceedings of the 19th International Conference on Mine Closure, Australian Centre for Geomechanics, Perth, pp. 1-13, https://doi.org/10.36487/ACG_repo/2615_69



Abstract:
The rehabilitation of Australian coal mines to achieve post-mining land uses (PMLUs) is constrained by a lack of suitable growth media. Coal mining rehabilitation therefore increasingly uses mined spoils to develop alternative growth media (AGM). However, successful AGM use depends on appropriate characterisation, field assessments and quality amendments. This study used a 2-stage assessment to rapidly evaluate germination rates of multiple species across varying mine-derived materials and to understand the influence of composted abattoir waste on growth media development for mine spoils and coal rejects under optimised nursery-scale conditions. Stage 1 assessed 27 native species and one cover crop across 12 mine-derived materials sourced from BHP's Goonyella Riverside Mine, including stockpiled topsoil, various Tertiary and Permian spoils, and coal rejects, under climate-controlled germination room conditions. Stage 2 further verified 7 top-performing materials based on cover crop germination response, with the best-germinating species transplanted into 52 L pots of amended materials mixed with nitrogen- and phosphorous-rich composted abattoir waste. Stage 1 results showed coal rejects yielded the highest germination of native tree and shrub species, while topsoil had the lowest germination, attributed to its high salinity and hard-setting properties. Coated native grass seed germinated poorly across all materials. Preliminary Stage 2 findings show compost improves AGM chemical and biological characteristics to support transplanted natives but offers minimal direct improvement to physical characteristics due to its low organic carbon content. The 2-stage approach provides a reliable, rapid method to shortlist pioneer species and verify AGM variations for achieving suitable PMLUs. It offers a targeted approach for screening mined materials, assessing ameliorants, and investing in native species with a proven germination and establishment record.

Keywords: rehabilitation, revegetation, native seed, germination, growth media

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