The following is an article by Dr Andrew Guzzomi, Dr Todd Erickson, Monte Masarei, The University of Western Australia which was published in the Mine Closure 2024 supplement.
Engineering restoration technologies to benefit the needs of mined landforms
Fifty-two million hectares in Australia and 20–40% of land globally is degraded. Rehabilitating much of this land is reliant on efficiently handling native seeds at scale. Common points of failure exist in seed-based rehabilitation practices which lead to underperformance and loss of expensive seeds. As climate change reduces the availability of viable seed stock, failure points are likely to be further stressed and therefore increasing the efficiency of seed performance in ecosystem rehabilitation for mined and agricultural landscapes is paramount. However, the process for collecting, storing, distributing and coating native seeds is an expensive and difficult exercise that hinders re-vegetation of large areas of degraded land, resulting from intensive mineral extraction and agricultural land use.
The majority of native seeds, such as the dominant grasses of inland Australia (Triodia species, or ‘spinifex’), have ‘fluffy’ appendages including floral bracts, awns, surface hairs and/or bristles making them difficult to handle. Their bulk takes up a lot of space in storage facilities and subsequent transport in trucks. The appendages stick seeds together which disrupts the mechanised sorting process, flow through seed planting machinery and the application of coatings that improve germination and seed placement. Whilst coating seeds with appendages with fine powders or binders is possible, resulting seed coats are too thick and inefficient, often re-imposing germination impediments previously alleviated through other treatments. Coating seeds without appendages is the only viable option for large-scale restoration projects to maintain batch germination potential and spread these seeds at scale. The solution lies in marrying up a detailed understanding of native seed biology with current and emerging seed and engineering technologies used in agricultural and horticultural industries.
Combining our engineering and science skills at The University of Western Australia (UWA) and Kings Park Science in 2015 we co-invented the Seed Flamer. The Seed Flamer’s flash-flaming process repeatedly exposes seeds briefly to a flame under strict species-specific conditions resulting in:
- precision removal of unwanted appendages
- improved flow properties enabling mechanical delivery
- increased bulk density
- no decrease in germination potential
- some species improving germination potential.
No other scalable technique exists to improve native seed flow and handling properties. Patents have been granted in Australia (2021), the USA (2020) and Canada (2024).
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Figure 1. (a) Patented Seed Flamer in action, (b) proven effective on a diverse range of species and seed morphologies
As a multidisciplinary team, we recognised that procedures for post-harvest handling, storage, germination and precision sowing of seeds must all be addressed in a harmonised manner to reduce seed wastage, enhance seeds and maximise seedling establishment – i.e. each step cannot be optimised in isolation. Therefore, in parallel, as part of the Global Innovation Linkages project titled ‘Eco-engineering solutions to improve mine-site rehabilitation outcomes’, administered by Kings Park Science, our research team established a range of seed-use and precision-seeding technologies for use in iron-ore mined landscapes of the Pilbara. This program:
- advanced the application of flash-flaming invention, through a series of evidence-based studies to a wider range of species in high demand for rehabilitation. By 2021, we had demonstrated that the Seed Flamer worked on over 20 target Pilbara and Southwest species
- combined these optimised flash-flaming treatments with additional seed enhancement technologies (including priming, extruded pelleting, and coating) in experimental laboratory, glasshouse, field-plot, and hectare-scale field trials with successful outcomes
- critically evaluated the field limitations of current mechanised seeding techniques used in large-scale rehabilitation and cropping efforts to guide engineering modifications or new designs required to improve precision-delivery of native seeds in adverse rocky, uneven and sloped landforms
- designed, constructed, and field-tested prototype seed enhancement and direct seeding machinery that can accommodate and efficiently deliver a wide range of seeds including those that differ in shape, size, and weight; and enhanced (primed, pelleted and coated) seeds, at multi-hectare scales and across multiple sites
- was awarded a patent in the USA for a native seed and mine waste dump compatible seeding machine (while patent was pending in Australia)
- quantified seed placement, seedling recruitment and rehabilitation performance using the engineered direct seeding machine(s) across different mining growth media and soil types.
Through these activities, we progressed a system to suitably treat and precision sow, diverse seed mixes (via purpose-built precision-seeding machinery), increasing success rates by up to 40%.
Balancing the goals of economic, social and environmental development is a significant challenge for the government, community and mining companies alike. Regulators expect mining companies to rehabilitate land upon mine closure, with some approvals requiring at least 70% biodiversity reinstatement of pre-disturbed species composition. The lack of sufficient technology to deliver cost effective and timely restoration of disturbed landscapes will result in major and lasting impacts on the mining industry’s social and environmental license to mine.
In late 2021 the Centre for Engineering Innovation: Agriculture & Ecological Restoration (CEI:AgER), co-endorsed by UWA’s School of Engineering and School of Agriculture & Environment was founded. Hon Stephen Dawson MLC, WA Minister for Innovation & ICT, officially opened the centre in late 2022.
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Figure 2. Comparison showing (a) business as usual seeding, and (b) outcome of combining our optimal seed enhancement technologies with precision seed placement
With our Australian patent granted, we established the Seed Flamer’s value proposition by demonstrating, through fundamental science, the improvement in plant establishment from recent field trials. Through our dedicated Seed Flamer Lab at CEI:AgER we processed 1,600 kg of flamed seed for the 2023 season and have flamed large quantities of seed for the up-coming Pilbara summer seeding season (2024–25). Additionally, through our CRCTiME Australian Seed Scaling Initiative project, we are testing and demonstrating the value of our approach through deploying our precision seeding machinery and seed management strategies into a range of highly altered systems that are commonly found in mined landscapes and severely degraded agricultural environments. Phase 1a began with demonstrating the technology in a range of mined bauxite landscapes in Western Australia, assess the transferability of the technology to other landscapes and develop the case for parallel testing at multiple locations on a national scale. The technologies have proven effective in these new environments, with shallow burial via our patented seeding device suggesting up to a doubling of seedling recruitment for some species compared to the industry standard of mechanised surface broadcasting. Research and development of new technologies and seed enhancement techniques to further improve mine site restoration is ongoing through the Centre for Engineering Innovation in collaboration with DBCA, BHP, Alcoa and the CRCTiME.
Working with UWA’s Office of Industry and Commercial Development we have built a technology stack combining the Seed Flamer with our precision-seeding devices and know-how to establish a UWA spinout Emergence Ecotech PTY LTD. This spinout will help permit efficient handling and distribution of native seeds at scale to establish plants in degraded lands in various mined, farmed, or grazed landscapes undergoing rehabilitation or restoration.