More than a ‘spray and pray’ environmental solution

Erizon’s six-step process to mine rehabilitation ensures the most efficient and effective way to meet remediation requirements.

Mine rehabilitation is a crucial issue for modern mining organisations.

This entails dealing with lingering issues related to excavation, regenerating flora and making the land viable for other uses if possible.

According to dust suppression and environmental expert Erizon, mining results in a major environmental impact which may affect more than the mine site’s immediate surroundings. 

The environment also suffers from both direct and indirect effects of mining. Some of the biggest issues caused are the loss of vegetation, biodiversity, soil and water contamination, and erosion. 

Mine site rehabilitation refers to the remediation of the negative effects sustained by the site and its surrounding environment during mining operations. 

It is often a legal requirement that mine sites must integrate environmental and social considerations throughout all phases of production. 

Revegetating with healthy, sustainable plant species that support existing ecosystems is the most efficient and effective way to meet remediation requirements.

Erizon’s approach to mine site rehabilitation takes into consideration the climate, the size of the site, the soil or rock condition and the chemical properties to prepare an appropriate remediation plan aimed at erosion control, dust suppression and successful revegetation of even the most damaged and degraded soils.

The restoration of vegetation can reverse the adverse negative impacts caused by the clearing and disturbance. 

Vegetation controls erosion, reduces land degradation, stabilises batters through root reinforcement and provides a habitat for biodiversity and animal species. 

One of the keys to Erizon’s success in this field stems from its intensive hydromulching process.  

Erizon senior environmental advisor Phil Barnett says hydromulching is a process that uses water as a carrier to spray seed, fertiliser, tracking dye and a binder/tackifier onto the seedbed, but has the benefits of Australian-tested cellulosic growth medium mulches added to the slurry. 

Hydromulching also provides a temporary layer of erosion control from wind and water until vegetation germinates.

Hydromulching provides a temporary layer of erosion control until vegetation germinates.


“The problem is that some soils are very vulnerable to erosion, particularly some of the soils that we are dealing with in mining areas that may not have much topsoil and are mostly made up of mining waste,” Barnett tells Safe to Work.

“The main purpose of it is to provide instant protection from erosion and it does that by providing a flat mass that is resistant to water erosion.

“It also has the same benefits as mulch in a garden, it retains moisture, it suppresses weed growth and it supports germination of the seeds we sow there that will grow their roots and get established to provide that ongoing sustainable support.”

Barnett says one of the highlights of Erizon’s program is the focus on safety.

“One of the advantages of our program in terms of safety is that it is a very safe way to carry out seeding,” Barnett says.

“You are not trying to run trucks up and down steep slopes and you don’t have personnel up on the slopes trying to plant stock – all of the process is done from a distance.

“The hydroRigs that are shooting the mulch out from their cannons can reach up to 100 metres so we can shoot from below the slope or from the top and completely seed without risk to vehicles or personnel.”

Barnett says one of the reasons Erizon stands out among its competitors is the company’s six-step process when applying and implementing its hydromulching program. These steps include:

Pre-site inspection

Rehabilitation involves careful analysis of a site’s requirements and condition to customise a solution that meets its goals. Soil samples are collected to determine the characteristics of the site.

Barnett says getting an early assessment allows Erizon to gain a greater understanding of the rehabilitation needs of each site.

“We like to actually go on site and walk around to get a better idea of a range of issues including soil type, the lay of the land and which seeds will be the most successful in this environment,” he says.

Drone survey

A 3D survey is undertaken to image map the area to a high degree of detail.

Barnett says each site is different and the inspection allows Erizon to get an early assessment of the best way forward, while tailoring the program to each individual site.

“The drones are also used as a quality assurance measure which is focusing on area so we can be truly accurate in our applications,” Barnett says.

Tailored solution

Selecting the optimum plant species, Erizon carefully applies the best solution considering the ability to facilitate growth, functional longevity and the erosion control effectiveness.

“Some companies have what I like to call a ‘spray and pray’ attitude where they will plant the seeds, add some fertiliser and hope for the best,” he says.

“At Erizon, we make sure we tailor the best possible solution to each site depending on what we believe will be the most successful.”

Uniform application

Hydroseeding and hydromulching process are optimal solutions for mine site rehabilitation, with each process providing its own benefits to deliver remediation success.

“There may not be a one-approach-fits-all solution for each particular job, so we are looking at the different levels of variability at each site,” Barnett says.

“While we offer a uniform approach, not all sites are uniform and we have to look at the best way to maximise growth and remediation success.”

Drone spraying

Latest drone technology allows Erizon to apply fertiliser, trace elements and soil probiotics four to eight weeks after seeding application to ensure ongoing project success.

“Using drones allows us to get an accurate measurement of the area we need to cover,” Barnett says. “It also allows us to get our rates of seeding right, as well as getting our rates of fertiliser right.”

Rehabilitation performance monitoring

Monitoring drones fitted with the latest scanning and imaging technology and sensors make sure the project is going as planned.

“This final part of the process measures how well the plant species are growing to make sure they take root and do their job of preventing soil erosion,” Barnett says.

“This continues on from our tailored solution phase and ensures we provide the continued support the site needs to complete the rehabilitation process.” 

This story also appears in the July issue of Australian Mining.

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