7 Principles To Help Build Sustainable Vegetation After Mining Disruption

Spray Grass Australia (SGA) utilises a framework that balances experience, science and the ability to offer revegetated solutions that are underpinned by outstanding results the first time around. Based on this ideology, we ensure that our approach supports confident decisions that provide our clients with a methodology that delivers fast, healthy, long-term growth and erosion control.

The ability to successfully rehabilitate mined areas is fundamental to the industry’s collective licence to operate, and a foundation for demonstrating the industry’s commitment to implement corporate social responsibly.

Throughout the full term phase of all mining operations, the change in topography as a result of stripping of vegetation, often causes erosion, unacceptable levels of runoff, and airborne particulate matter in the air, which can pose contamination risks to nearby communities and water systems. In consideration of these potential contingencies, a management plan should be implemented on-site as soon as possible.

The following seven principles will show you how to achieve successful and sustainable vegetation for mine closure sites by understanding what factors to prepare for and what research to undertake.

1. Preparation

Preparation is intended to assist in managing existing native vegetation and other environmentally sensitive areas on the site of a proposed or existing mine site. Planning for rehabilitation and the implementation of vegetation seed should start well before the first tonne of soil is removed from the mining site. This process begins with drawing up a rehabilitation plan before the commencement of the initial mining phase. This strategy is a more effective and cost-efficient process than if a client began preparation, nearing the time of the mine closure.

The early implementation of a rehabilitation plan provides ongoing sustainable management for native vegetation and ensures that an environmental specialist can promptly remediate land clearing and modification activities associated with soil disruption. This preparation is essential in developing a comprehensive and integrated approach to guide the immediate and long-term management of native vegetation.

2. Soil Quality

Good quality soil is essential for successful revegetation; without fertile, nutritious soil, any efforts made to germinate seed growth, will be insignificant. In essence, soil provides the necessary food, water and oxygen that is needed by plants to support healthy growth and successful development of seeds, so it is vital to ensure that the soil is of good quality before commencing rehabilitation.

Before the commencement of any mining activity, topsoil should be stripped off and stored in stockpiles until the mine is ready to rehabilitate the area. Using this topsoil in the restoration process can improve the productivity and rate of vegetation growth. However before the rehabilitation process can commence the topsoil is required to be tested. This process is designed to provide essential information needed to determine what adjustments must be made to ensure that soil quality provides a favourable growing environment. Unfortunately, various factors such as stripping, storage time and soil management can present adverse effects on the soils chemical, physical and biological properties.

Soil testing conducted by the team at SGA looks closely at these properties and the various imbalances of the substrate such as pH, fertility, microbial community and different soil nutrients. Based on an educated understanding, the substrate is restored as a result of creating a tailored amendment solution that will recover its ecological integrity by counterbalancing any significant changes that may affect the soil’s ability to facilitate growth. If the soil if far beyond repair, Enviro Soil, a topsoil alternative, engineered with Biotic Soil Amendments designed to improve the weak soils that lack essential nutrients and bioactivity to support vegetation.

The earlier the rehabilitation commences, the fewer soil modifications are required, therefore underpinning the need to provide an implementation plan and strategy as soon as possible.

3. Water Quality

The quality of water used for initial revegetation and continuous irrigation of seed through its growth period is essential to ensure that adequate germination is reached and effective erosion control is achieved. The water quality can vary dramatically based on the water source and in some circumstances, can not only be inadequate but even detrimental to revegetation goals.

A significant concern placed on mine site rehabilitation is the potential use of bore water, which can be contaminated or be of substandard quality. Before utilising any water throughout this process, it is vital to have it tested to ensure that there are no significant contaminants present that may require ameliorates to mitigate the effects of salt or pH.

Salinity can cause a build-up of salt in the soil, stunting growth or even inhibiting grass germination. Once sodium levels have built up in the soil, chemical amelioration and flushing with freshwater is likely needed to rectify the problem. Such products can be added during spraying and can mitigate the salinity issues; however, over the long term, a more suitable water source should be found. A similar problem can also be detected with a high level of metals in the water which may be of concern on mine sites in particular, although this problem is harder to rectify.

Water with a pH that distanced from neutral pH seven may cause vegetation to grow poorly or not at all if it blocks nutrients to the soil. The water pH can be adjusted relatively quickly, so it’s essential to know if this is necessary.

4. Seed Type

Re-establishing vegetation requires a reasonable understanding of what the land is capable of supporting. Establishing a cover on the exposed or disrupted area is essential for proper soil management and erosion control. The correct plant species must be selected to suit the project based on several factors, including the project location, site conditions, soil characteristics, intended use and maintenance requirements, all of which will safeguard success.

SGA strongly recommends that seed for any mine site revegetation operation should be collected from the local area. However, if the soil testing indicates extreme inbalances such as increased salinity or waterlogging, the selected seed may need to be altered to align with the quality of the soil. These site changes will affect what vegetation will be able to germinate in order to produce sustainable vegetation effectively.

5. Solution: Quality & Delivery

Based on the soil quality and environmental requirements, SGA will establish an exclusive vegetation solution designed specifically for the sight at hand. We spend considerable time assessing and reviewing our approach to each project. We understand that no two projects are the same; therefore, we take a tailored approach to ensure each project is customised. We carry into account the erosion control product effectiveness, ability to facilitate growth and the functional longevity required for that protection.

The most effective mine site solution suggested is hydromulching, a superior product designed for surface stabilisation on mine sites and is an effective and viable option for vegetating vast expanses of land quickly and easily, whether they are flat, hard to access or significantly sloped. This vegetation strategy underpins active vegetation growth and controls any pollution and erosion that may occur, helping to cease further environmental damage than necessary.

Our highly trained technicians ensure that the solution is mixed and applied according to guidelines to ensure that product mixes, ratios, and percentages are correctly implemented; by adhering to these guidelines, we can maximise the performance of our solutions to meet the required project goals.

6. Timing of Application

Choosing the best time to apply your revegetation solution such as hydromulch or hydroseed is crucial to all rehabilitation projects, as the weather can play an important part in the success of achieving vegetation.

The amount of expected rainfall is a significant factor that can determine how fast germination and establishment occurs. Timing of application also affects project costs, i.e. if there is an inadequate rainfall forecast due to dryer seasons, irrigation may need to be supplied, adding to water consumption and labour costs. The average temperature can also play a part in successful revegetation, particularly with hydroseeding. If the temperate is too cold, and mulch hasn’t been used for insulation, the rate of seed germination is hindered, however, if the temperature is too high, more water is needed to keep the seedling healthy after germination.

Depending on the site location, all these variables are taken into consideration and discussed carefully with the client.

7. Post Project Monitoring

Once a revegetation solution has been applied to the site area, post-project monitoring can commence. Continual monitoring of the project progression is the best way to make sure that all site requirements and compliance issues are addressed promptly. SGA has worked together to create a service that can exponentially increase project success rates through the means of Envizo, our realtime performance monitoring software system. Cameras and sensors allow us to receive 24/7 remote access to a full range of performance indicators including live video and reporting data on growth performance, advanced weather data, rainfall, volume, soil moisture and salinity levels. This information guides onsite performance measures and allows room to mitigate contingencies that may occur.

We work together with our clients to capture the data needed to ensure project success is achieved by demonstrating an understanding of their delicate landscape and providing innovative techniques to return it to a diverse and functioning ecosystem.