Soilwater Group est. 2000

Adam Pratt established the Soilwater Group, a Perth-based soil and water resource consultancy, laboratory and Research & Development (R&D) organisation. For over 20 years we have been providing total package solutions to our clients, both within Australia and overseas

Our mission is ‘Achieving Future Growth’ for our clients

Soilwater Consultants (SWC) is the consulting arm of SWG housing a team of experienced engineers and scientists. Lead by Adam Pratt the team has traveled around the world implementing their award winning techniques for Rehabilitation and Closure Monitoring

Soilwater Analysis (SWA) is the analysis arm of SWG providing a commercial soil and water testing laboratory.

Soilwater Technologies (SWT) is the research arm of SWG developing future solutions for environmental management.

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Adam Pratt has over 20 years’ experience in the mining sector, both within Australia and overseas.

In 2000, Adam Pratt formed the Soilwater Group (SWG), comprising Soilwater Consultants (SWC), Soilwater Analysis (SWA) and Soilwater Technologies (SWT).

Contact Adam Pratt

The Role of LiDAR in Mine Rehabilitation and Closure Monitoring

It is generally accepted that for a mine site to achieve closure and relinquishment it must meet specific standards or completion criteria so that an objective assessment can be made. The four tenets of mine closure are – safety, stability, non-polluting and sustainability. Whilst the principles of safety, non-polluting and sustainability are relatively easy to monitor, with established objective measures, the tenet of stability is less easily monitored and it is generally left to subjective assessments to determine whether a post-mine landform is stable or not.

Although this is case, LiDAR (or Light Detecting and Ranging) does offer a method to objectively assess stability, which can be used (and asked for) by the regulators to confirm stability and ensure compliance against completion criteria. But, as with all methods of assessment there are pitfalls that must be considered, both prior to collection of data and also in the application of the data.

In essence there are two main types of LiDAR – airborne and ground-based. At the present moment airborne LiDAR is generally restricted commercially to aircraft and whilst drone or UAV LiDAR is considered the holy-grail it’s application is generally restricted academic or government / defence force purposes. With regards to ground LiDAR, it can either be stationary or vehicle-mounted.

In choosing which LiDAR to use it all comes down to how you want to use the data. If wanting to measure small erosional features, establishing whether an erosional feature is growing and at what rate or accurately quantifying sediment loss (in t/ha/yr), then airborne LiDAR is not the answer because the spatial (namely horizontal) resolution (i.e. distance between adjacent points) is greater than the feature you are wanting to measure. With airborne LiDAR the point cloud resolution is controlled be the flight altitude, and planes simply cannot fly low enough to obtain a point resolution sufficient to measure small scale features, which are often the precursors to larger stability (and safety) issues. Airborne LiDAR is therefore generally only suited to pre- and post-mine topographic surveys.

Stationary ground-based LiDAR is the perfect tool for quantifying surface stability of post-mine landforms and in providing quantitative data that can be used to compare with established completion criteria. With this method of LiDAR the spatial resolution is in millimetres, which is ideal for detecting erosion and measuring sediment movement, and at its highest scanning resolution there are over 1,000 data points per square metre. Given this level of detail and accuracy the same spatial point(s) can be measured overtime to assess sediment loss (erosion) or gain (deposition) and establish the overall stability of the post-mine landform.

Although ground-based LiDAR is the perfect tool for measuring post-mine landform stability, it is generally only applicable in the early stages of rehabilitation when the revegetation is not established and reasonably dispersed. Given LiDAR cannot ‘see through’ vegetation, as soon as the revegetation gets established and the foliage cover increases, the role of ground-based LiDAR diminishes as there is not enough exposed ground to get accurate measurements. Although this limitation exists, it is generally in the early years of rehabilitation that erosion and instability are an issue and once the revegetation becomes established and the ground surface is protected from rain-drop impact the incidence of erosion decreases; hence there is less requirement to measure.

One critical aspect that I must raise when setting completion criteria for erosion and surface stability, is that whatever criteria is established and agreed upon it must be realistic and be measureable. For example, the Department of Mines, Industry Regulation and Safety (DMIRS) here in Western Australia commonly default to a stability value of 5 t/ha/yr as determining whether a surface is stable or not. Although this value might be considered realistic, when you delve deeper into what it actually means, a value of 5 t/ha/yr equates to a uniform sediment loss of only 0.3 mm over the surface. There is no instrument or measuring device that can detect such a small change in elevation over the spatial scales considered in post-mine landform stability. Given it is not physically or feasibly possible to measure 5 t/ha/yr, then why does DMIRS default to this value for stability? A more realistic completion criteria for stability, and one that could be accurately measured using ground-based LiDAR is 30-50t/ha/yr, which equates to 1.8-3 mm over the surface.

In this post I haven’t delved into the realm of photogrammetry which is what is obtained using drones or UAV because there is a lot of smoke and mirrors to what can and can’t be achieved with this technique.

HAPPY BIRTHDAY! Soilwater turns 21

In May 2021, the Soilwater Group turns 21 years old! It really does only seem like yesterday that Soilwater was established in my home office in Perth. It’s certainly been a whirlwind ride. They say that 60 % of all businesses fail in the first three years, so the fact that we have survived 21 years is a fantastic achievement and testament to our current and past personnel.

Over the last 21 years Soilwater have completed projects for a range of national and international mining companies, including BHP, Rio Tinto, FMG, Roy Hill, Barrick Gold, Cliffs, Northern Star, AngloGold Ashanti and the list goes on. Our team have worked in some amazing countries including Kenya, Mali, Namibia, Eritrea, Mongolia, Kazakhstan, and some incredible places in Australia, including Kakadu, Carr Boyd Ranges and Lake Argyle, Koolan and Cockatoo Islands, Chichester and Hamersley Ranges and of course the beautiful jarrah forest of the southwest of WA.

So what is the secret to our success?

Over the last 21 years I have had many people ask this question and my response has always been flexibility. When I first started Soilwater all we did was soil surveys. Whilst this was good and kept us busy for the first few years there was no way we could have survived if we remained solely in this field. We had to branch out into different fields to build a sustainable business. Our first and most logical expansion was into the field of geochemistry, including acid sulphate soils (ASS) and acid and metalliferous drainage (AMD). We then expanded into geochemical and unsaturated zone modelling, hydrology, and then into post-mine landform design, construction and ultimately mine rehabilitation and closure.

In order to be sustainable a small business must be flexible and be able to move rapidly into new and developing areas, without too much effort or cost. If this can’t be done then there is a risk that a business will stagnate and eventually die as money runs out. It is important to acknowledge that nearly all industries are cyclical and therefore they will change overtime. If a business can’t respond to this natural cycle then it will not likely survive.

Although change and flexibility is an essential trait for a small business it is easier said than done! In the consulting space we all value our regular clients who provide us with stability and safety. But, this doesn’t help in expanding a business or in changing or adding new fields. It is extremely difficult keeping existing clients happy and well supported, whilst trying to add and secure new business. In order to attract and service new clients, considerable time and effort is required to be invested, generally at the expense of older, existing clients. If not managed well, then existing clients will generally lose patience because they expect the same level of attention as they have always had, and you cannot tell them that they are no longer the priority and they must share your time; this generally does not go done well.

So what could have been done differently to improve our success?

When I first started Soilwater I was in the second half of my PhD at the University of Western Australia. Given I went straight from academia to consulting I did not have any industry experience and no industry networks. This made life very difficult and it was a slow road building my networks. Although this was the case, I was very fortunate to have a good ‘first’ client (Iluka Resources) that had many projects around Australia. Servicing Iluka and their many sites kept Soilwater busy for the first 10 years, but this came at the expense of building my network. 

So, what I should have done is transitioned from academia to industry first, in order to make contacts, and then moved across to consulting once I had greater industry exposure. If this alternate path was followed then I feel the road to where Soilwater is now would have been very different.

So where to from now?

Soilwater has many more years to come and many more challenges and opportunities that I look forward to. It’s been a fantastic first 21 years, now it’s time for the second half…

All the best,

Adam Pratt

Director | Principal Soil Scientist

Adam Pratt is a founding director of Silica Earth Resources and between from 2015 to 2018 Adam Pratt was the EHS Manager for Vimy Resources.

In 1996 Adam Pratt completed a BSc (Env) with Honours at Murdoch University and in 1997 he started his PhD in Soil Science at the University of Western Australia (UWA).

Adam Pratt has presented at numerous national and international conferences in the field of mine rehabilitation and mine closure. 

Adam is currently the CEO of Vytas Resources, a Perth-based silica resource and technology development company. 

Soilwater Group won the 2018 AMEC Environment Award for the Application of Ground-Based LiDAR for Rehabilitation and Closure Monitoring. Each year AMEC presents a number of industry awards to recognise the outstanding contributors to the mineral exploration and mining industry.
The AMEC Environment Award reflects the increasing importance of managing environmental impacts of mineral mining and exploration projects. It is made to a company that goes above and beyond in their management of environmental impacts or is developing innovative methods to achieve better long term environmental outcomes. The criteria for the award are relevant to mineral exploration and mining projects; degree of innovation from current/past processes and potential benefit or significance to industry.