As operators recognise its scale and speed advantages, aerial seeding is becoming an increasingly prominent practice in the Australian resources industry.
While mine sites are of varying sizes and profiles, they are all subject to their own environmental obligations, much of which necessitates the progressive rehabilitation of land throughout a site’s life.
Seeding is an important component of mine rehabilitation, enabling the restoration of vegetation and ecosystems that once inhabited the area before any resources were extracted from the ground. However, the practice has long been confined to light vehicles or dozers, which can present safety hazards and disturb the ground as they seed.
But seeding methodology is evolving, a movement led by environmental technology companies such as Dendra. Drone fleets are surpassing traditional methods due to their speed, accuracy, safety and cost-effectiveness.
Dendra senior drone pilot Michael Whitehouse, who operates unmanned aerial vehicles (UAVs) for a living, said aerial seeding can cover areas “double, nearly triple” the size of traditional practices in the same timeframe.
showcasing automated
flight paths for diverse
seed mixes, covering 40 hectares.
Image: Dendra
“Our method is scalable because we can use more drones when needed, which is a small equipment outlay compared to using more dozers,” Whitehouse told Australian Mining.
“We can have multiple drones operating at once, significantly increasing the amount of seed we can spread.”
Each Dendra pilot can operate up to three drones at a time, and more pilots can be deployed depending on the size of the seeding job, which means up to 10 drones can be seeding at one time.
“With more pilots and drones, it exponentially increases the number of hectares we can cover in a day,” he said.
“All our seeding missions are pre-planned, meaning once we receive the seed mix and area boundaries, we calibrate the patented spreaders without wasting any of the seeds, then work out the swath distance and our spread rates.
“We can then generate the flight lines, so that each drone can complete its own seeding mission autonomously.
“We average between 15–20 hectares in a day, but on occasion, I’ve spread at least 40 hectares in a day. We can scale up or down as necessary to meet the required seeding deadline.”
Throughout a mission, the drone pilot monitors the spread rates and makes adjustments where necessary, ensuring the right deliverables are achieved.
The undulating terrain of a mine site can not only render traditional seeding methods difficult and less effective but also hazardous. By removing the human element from the seeding environment, Dendra’s drone technology has demonstrated its safety potential.
“We can seed slopes with an incline of at least 20°, which can be a dangerous, uneven environment for traditional seeding equipment,” Whitehouse said.
“And with mine sites becoming increasingly safety conscious, there is a greater emphasis on risk mitigation, which is generating more interest in aerial seeding.”
Depending on the environment and location, seeding is often conducted during the wet season. The sodden, muddy ground is another risk factor for traditional seeding methods – a challenge that presents no issues to drone fleets.
Image: Dendra
Operators are also likely to achieve greater restoration outcomes through Dendra’s drone technology.
“Not only do our drones avoid soil disturbance, but we can quickly mobilise to site and seed straight away which, from a biological point of view, means seeds are being dropped soon after the soil has been ripped, optimising the seed’s planting and potential for germination,” Dendra product marketing manager Maxim Stoker told Australian Mining.
“Conversely, a dozer can compact the soil and spread weeds and create gullies. Sometimes it can even be a struggle to seed the way land needs to be seeded or achieve the right native ecosystem design within that seed mix, whereas Dendra drones are engineered purely for that.”
These ecosystems have optimal seeding seasons, which, depending on the weather, is a time of the year that provides the best environment for germination.
Whitehouse said he was booked with back-to-back seeding jobs from November to February, and the ability to quickly complete aerial seeding at scale and move onto the next job means Dendra is able to execute more projects in a tight window.
“Everyone wants their seeds to be done at the same time and you also have all the ripping that needs to be done,” Stoker said. “So you have a really small timeframe of seeding that needs to be achieved.
“The drones come in and do the job really quickly and get out without disturbing the soil; this reduces risk to personnel. And if a dozer needs to rip the land and the availability of that dozer is delayed, then your whole seeding program is thrown out of whack.
“Dendra removes the reliance on shared machinery because we bring our own drone fleet in, have our own pre-planned missions, seed the land and get out.”
Across successive seeding seasons, mining companies can significantly reduce operational expenditure by implementing Dendra’s rapid and scalable aerial seeding solution. Being able to reliably meet deadlines also means seed is not wasted.
“Seed is an expensive commodity, and hard to collect at times,” Whitehouse said. “If anything isn’t seeded because of operational delays, this can have a huge cost, with the seed not necessarily usable the following year.”
“Having engineered a patented seed spreader, we can ensure that seeding happens when it needs to, and know we can spread large portions of seed in a short period of time, all within a homogenous seed mix, making it a huge cost consideration for sites.”
Image: Dendra
While Dendra offers its aerial seeding solution as a standalone service, it also forms part of the company’s holistic RestorationOS offering.
“We can offer a whole revegetation solution,” Stoker said. “From the initial seeding, we can then map it over time, see exactly how the land has become revegetated, and see if and which weeds are coming into the mix and harming revegetation. All this comes together to illustrate trends as to how a mining company is progressing against its environmental KPIs.
“Aerial seeding is part of a broader holistic approach to restoring ecosystems. It’s not efficient to just seed and hope for the best. Rather, the best restoration outcomes are achieved when you follow the process from
end-to-end.”
Dendra deploys drone and remote sensing technologies to map and survey land at scale. This enables miners to have a detailed, bird’s eye view of their entire environmental ecosystem.
Artificial intelligence is then used to convert data into actionable insights, which could inform the next seeding window, support statutory reporting, or enable a mining company to manage other environmental risks.
This all culminates into a progressive ecosystem restoration model, with Dendra being a partner throughout a mine’s life, ensuring the best rehabilitation outcomes and post-mining transition.
This feature appeared in the October 2024 issue of Australian Mining.