Australian based geotechnical monitoring group Geomotion, has successfully come to a heads of agreement with SkyGeo for their cutting edge InSAR satellite monitoring technology to be used in Australia, Singapore, Malaysia, Myanmar and Indonesia.
Geomotion sees InSAR as complementary to existing instrumentation, not as a replacement, working so well together to offer their clients information that has previously been nearly impossible to obtain
InSAR stands for Interferometric Synthetic Aperture Radar and is a proven technique for measuring ground movements. Satellites record images of the Earth, and these images can be combined to measure movements of the ground surface.
InSAR is particularly useful for monitoring dynamic position changes. InSAR’s broad spectrum of impressive features allow for a new depth of insight for projects. A large number of measurements and weekly updates provide a detailed insight in the slope and speed of subsidence. A sudden drop of a small area might be a reason for local inspection. Wider gradual subsidence tells a different story.
InSAR allows for possible millimetre accuracy, measurements of areas as small as 100m2 up to 10,000km2 and up to 100,000 measurements per km2. Additionally, the data archive goes back to 1992 and covers 70% of the Earth’s land, meaning in some cases it is possible to have data dating back up to 25 years.
InSAR presents viable and important solutions across many industries, including Mining Stability, Tailings Dam Stability, Civil Engineering and Energy, including oil and gas projects both onshore and offshore.
Mining stability monitoring is a service to provide persistent geotechnical risk surveillance to identify areas of abnormal surface movement over time. Mines need to be up and running 24/7 and Geomotion helps achieve that goal by identifying instabilities early. By assessing time-dependent shape changes in InSAR data, geotechnical domain experts can identify patterns of instabilities.
This is a direct pathway to improve asset management in mining operations. Combined with strategically placed geotechnical or structural instrumentation a comprehensive monitoring plan is established.
Each mine has several areas of high geotechnical risk, that each require dedicated iterative assessment. Tailings dams pose a special category of risk. Because of environmental issues in the recent past, most mining experts are now looking for continuous monitoring systems to predict instability better. Solid tailings are often used as part of the structure itself and with the tailings being liquid or a slurry of fine particles within groundwater, significant instabilities arise in a variety of ways that are usually not completely understood. With InSAR, Geomotion can help with this understanding. We characterise and quantify these time-dependent degradation processes on a wide area scale and identify different dynamic patterns. Monitoring these patterns continuously is a proven permanent risk management method.
Geomotion/SkyGeo JV configures InSAR monitoring solutions for their clients, each with a graph of deformation over time. Risk management practitioners use this for predictive maintenance. Geomotion/SkyGeo JV monitors subsidence for many civil engineering projects in this way including roads, railways, dams, bridges, tunnels, airports, pipelines, neighbourhoods, sewage systems, buildings and water defence.
InSAR technology is available from the Geomotion/Skygeo JV now. Enquiries regarding how InSAR can benefit your project can be made today by contacting Geomotion’s offices on 1300 884 542 or click here to send an email. Alternatively, use the form below and a Geomotion representative will get in touch with you soon.
The City of Amsterdam is facing the huge task of assessing and potentially replacing 200 km of the quay walls along its charming old inner-city canals. Adjacent historical buildings are often susceptible to damage by nearby construction activities. Satellite InSAR is being used to monitor areas across the city. Monitoring subsidence is seen as a vital tool in the efforts to preserve the physical charm and historical assets of this scenery.
Deltares, the City of Amsterdam, TU Delft, and SkyGeo have published an article on the reliability of PS-INSAR usage compared to regular ground levelling and general InSAR data. It describes how the PS-InSAR process can considerably reduce the current lengthy period required for levelling updates and verifies the improvement in reliability when using a locally optimised SkyGeo InSAR dataset.
The City of Amsterdam started innovating by using levelling techniques centuries ago, when they introduced the NAP (National Reference Height). They have been measuring and placing markers on buildings throughout the city to aid in the assessment of subsidence. This is a profound effort as the inner-city is completely built on soft soil. Levelling and InSAR data usage are both used across the city to provide valuable insights on deformation. A direct comparison between levelling and satellite measurements means little, but researchers found a specific statistical procedure that is applied to levelling and satellite measurements to verify their reliability and determine the rate of vertical deformation of the buildings.
Permanent Scatterer SAR
The Permanent Scatterer SAR technique can measure deformations of objects with high reliability. Satellites launched in the last decade produce raw data to obtain deformation time series with high temporal and spatial resolution. Martijn Houtepen, InSAR Applications Expert at SkyGeo, was asked to supply two different datasets for the Amsterdam city area. One general dataset covering the entire city and a tailor-made locally optimised InSAR dataset. Three case studies were reviewed. The results exhibited a near 100% coverage for buildings in the SkyGeo locally optimised dataset. These structures all had reliable measurement points, greatly outnumbering general InSAR and regular levelling results.
Conclusion of the PS -InSAR study
There is merit in the insight building fine-tuning of local datasets. Caution should be considered with generic, publicly available, InSAR datasets. All three case studies showed deformation rates of the satellite measurements are significantly higher than those of the levelling on the same buildings. Locally optimised PS-InSAR satellite measurements are most suitable for assessing the deformation rate of buildings in the Amsterdam inner-city.
PS-InSAR is available for Geomotion customers looking to scale trust with InSAR data.
Article courtesy of SkyGeo
Failures of tailings dams are one of the most hazardous processes that may occur and can cause extensive damage to life, property, and health. The mining industry has experienced several significant dam failures in recent history: Merriespruit 1994 (South Africa), Omai 1994 (Guyana), Aznalcollar 1998 (Spain), Baia Mare 2000 (Rumania), Aitik 2000 (Sweden), Bento Rodrigues 2015 (Brazil) and recently in Mexico (2018). Historical records of tailings dam failure are of about 20 events per decade, showing a tendency to shift from developed countries to developing countries.
For decades, tailings dams have been monitored via manual monitoring systems. This typically involves selected spots along the barrage, where boreholes are drilled and periodically visited. Here, manual measurements are taken with a variety of instruments, mostly consisting of water level meters, piezometers, or inclinometers. However, this kind of measurement does not produce sufficient data to consistently measure the performance of the embankment dam if sporadic readings are collected manually. As such, some failures of dams can be attributed both to the combined effect of rapid dike construction and to poor maintenance and monitoring – usually through wired and/or manual means. Below are some reasons why a wireless monitoring system is a key tool for the safety management of the embankments.
1. Improves knowledge of the most critical potential failure mechanisms
It is important to identify the main cause of failings in order to plan better and to implement the correct measures to stop them.
Tailings dam failures can originate from overloads, anomalous behavior of the material used to build the dam (normally tailings), or from problems with the drainage mechanisms, which result in an increase of pore water pressure, and therefore a loss of resistance.
They can also result from other things, like poor monitoring systems, for instance. With manual or wired in-situ readings, operators do not have sufficient amounts of data to gain a clearer picture of the main factors playing a role in failure mechanisms. This massively increases risks in and around tailings dams, as those supervising the area cannot predictively act in order to stop potential failures. The amount of data and regularity with which it is collected through wireless monitoring solutions provides a solid basis for a correct risk analysis, and for building risk-potential models. This is key for long-term risk-planning and for understanding critical failure mechanisms.
2. Detects situations that are likely to trigger a failure of the dam
Real-time data-gathering means that operators have continuous knowledge of the dam’s status. It also means that they can very quickly build “normative” models of how the dam should be behaving, meaning that any anomalies are flagged up as soon as they occur. This allows operators to detect situations that are likely to trigger a failure of the dam – such as water level exceeding a certain limit, or acceleration of horizontal displacements in depth – and to respond preemptively to these situations.
As such, wireless monitoring systems permit for the implementation of corrective measures as soon as possible, preferably before any kind of incident can take place.
This is key not only to reducing risk and saving human lives but also to a business’ profit margins. Post-incident remedial action and the downtime of the dam cost significantly more than predictive maintenance activities.
3. Serves as a tool for designing the dam’s growth
Accumulated data-sets gathered through wireless monitoring devices are key to the successful future planning of the dam’s growth. Rather than create a growth strategy based on historical memory and previous actions, with a wireless monitoring solution, operators can use solid data to implement models that show the future probable status of the dam and its environs, and allow them to plan more accurately for any possible future changes and incidents within the context of its growth.
As part of an Operational Intelligence solution, wireless monitoring data can also be used to create “digital twins” or parts of the dam, or the whole site, in order to virtually model future actions in a “videogame” version of the environment.
Either way, wireless monitoring means that the risk of future failures and incidents is significantly reduced, through using the most scientific methods possible to calculate future risk potential.
4. Provides a sound basis for the establishment and implementation of the proper response in case of a failure involving human hazards
Equipped with the ability to model future incidents and predictively respond, operators can establish set responses to particular incidents that regularly happen, and set up crisis contingency plans in the case of an emergency.
This is all enabled through the constant relay of precise data about the status of different parts of the tailings dam.
For example, wireless nodes transmitting data from water level meters and inclinometers installed on boreholes enable periodic controls. Piezometric sensors provide information regarding the pore water pressure, and the measurement of the ground displacement in depth is automated by an in-place inclinometer which allows operators to measure the horizontal displacement on depth. Waste management gauges, which measure the water level in the dam or settlement cells to monitor the settlement processes of the walls and surroundings, are also crucial here. Moreover, meteorological stations measure variables such as rainfall and wind speed and are critical in terms of allowing operators to consider and plan for new climatic scenarios – especially in the context of climate change and increasingly erratic weather patterns. Again, this allows for predictive and early-stage responses to any potential anomalies that arise, massively reducing the risk of incidents occurring.
5. Provides long-term monitoring with very little maintenance
A monitoring system that is both long-term and low-maintenance is absolutely critical for tailings dam environments.
Manual maintenance of sensors and data-loggers – and more – is in itself incredibly risky, meaning that maintenance of a monitoring solution must be minimal.
This requires durability so that equipment can survive in sometimes very harsh physical conditions; longevity of battery life, so that equipment does not need to be placed frequently; and long-distance transmittance, so that it can continuously relay data from difficult, hard to reach environments over long periods of time. Depending on the system used, the long-range communication between the gateway and the dataloggers in most wireless monitoring systems allows for a distance of up to 9 miles or 15 km between the gateway and the data-loggers in an optimal situation. In the context of a mine, this means that, by placing the gateway in the mine’s central office, almost any point of the mine where a sensor is placed can be reached, meaning that no manual readings ever need to take place. Embedded, long-life batteries make remote data acquisition systems autonomous for up to 10 years, enhancing the maintenance cycles of the monitoring system. This massively reduces risks as equipment rarely fails, meaning continuous, accurate readings for years. In turn, this decreases potential downtime and means that there is no need to manually maintain the monitoring system.
Wireless monitoring is realistically the only way to properly monitor tailings dams to prevent and manage failures. Many mining and damming companies still rely on manual or wired in-situ readings as part of their core instrumentation and monitoring processes. This is problematic as tailings dam failures are incredibly dangerous – indeed they threaten lives – but manual monitoring systems do not give sufficient amounts of data to allow the situation on the ground to be monitored consistently or frequently enough to prevent this kind of incident from happening. Moreover, wired in-situ monitoring systems – using cables, for example – are vulnerable to physical damage over time. It is hard and expensive work to protect the cables, and they require a wired centralized acquisition system that relies on external power supply (solar kit or electricity).
Wireless monitoring systems eliminate all of these problems, providing a real-time, continuous flow of data enabled through reliable, long-distance, low-energy and low-maintenance technologies. The flexibility and longevity of this kind of system fit well with an embankment dam and its raises. Crucially, wireless data acquisition systems can transmit readings from in-ground sensors that measure the cause of any potential anomalies, not only the effect, as is often the case with other instrumentation and monitoring systems. Measuring the cause allows for the implementation of early, preventative actions if any anomalous performance of key variables is detected. Transmitting data from all these different sensors means that all site areas are covered and hazards are therefore reduced. This comprehensive monitoring system is thus indispensable to any tailings dam company, significantly reducing the risk of failure onsite through producing actionable insights that allow operators to make better, evidence-based decisions.
Article courtesy of Worldsensing
Albany Wind Farm is an 18 turbine wind farm with the southern hemisphere’s largest wind turbines. It has the capacity to meet 80% of Albany’s power needs.
Geomotion were appointed by WSP to provide a monitoring system for the farm. The aim of the project is to monitor the service life of the turbine foundations at Albany Wind Farm.
By installing tiltmeters on the base of three of the twelve turbines, WSP is intending to establish the extent of foundation movement, the extent of fatigue damage on the tensioned ground anchors and the extent of fatigue damage to the concrete foundation.
Geomotion installed two Biaxial Tiltmeters to each of the three chosen turbines at 90° angles form one another with the intention of monitoring the vertical movement of the foundation in four directions.
The sensors where glued to the base of each turbine mast using high strength epoxy resin glue, each covered with a protective metal vandal proof cover.
To allow the client to gain near-real time data of the foundation movement we attached these sensors to YDOC, Model number WL-N315ADS Data loggers. These loggers record the tilt on a 15 minute basis and provide a report email daily.
Premier Coal is situated in the Collie Coal Basin in the South West of Western Australia,
approximately 200km south-south-east of Perth. The mining operations are about 15km east of the town of Collie, which is situated in the jarrah forests of WA.
Premier Coal Mine produces a clean coal with low ash and sulphur content such that it does not need to be washed and requires only crushing, sizing and blending prior to use. The coal handling equipment installed at the Premier Coal Mine is very effective. The system has been designed to supply coal in a very consistent way so that there are no variations in quality.
The coal handling plant consists of a crusher, screening plant, stockpile stacker, reclaimer and delivering system for Premier’s customers, either by conveyor, rail or truck.
As part of Premier’s open cut pit monitoring, over 29 piezometers were installed in 11 locations across the area. Previously, the data was collected manually by site personnel.
Geomotion proposed the Loadsensing G6 Data Logging system to automate the collection process, including a 5-channel node at each location and a centralised gateway. The data is presented directly in Premier’s data management software.
This system fully automates the collection and presentation of piezometer readings, ensuring the data available for analysis is kept up to date at all times.
Mascot Towers is the high-profile residential building in Sydney that was evacuated in June 2019 due to serious concern about its structural integrity.
With the rapid growth of our cities and the increasing need for affordable housing, buildings similar to Mascot Towers are popping up quickly throughout Sydney and other major Australian cities.
Concerns were initially raised when significant cracking began to occur suddenly through the building’s basement foundations (see image below).
Geomotion were engaged by the remedial engineers to supply and install structural monitoring equipment on critical areas in the building's basement.
A site walkover was undertaken on the Monday morning after the evacuation, the same day Geomotion was first contacted. Sensors were installed and commenced sending live data to Geomotion Cloud, Geomotion's online data hosting platform, by the very next day.
Geomotion's precision monitoring systems can be utilised, not only after a major structural failure event, but also during construction and throughout a building's lifespan to provide critical information on a building's structural health, early warning alarms and peace of mind for all stakeholders.
Geomotion technicians carried out the installation of 4 tilt meters on critical areas on the basement slab, with four additional tilt meters set to be installed soon.
A 3G telemetry gateway was installed to enable data to be transmitted remotely – importantly removing the need to be inside the building to retrieve data.
Geomotion's data team set up the online portal on Geomotion Cloud, where data is displayed in easy to interpret plots.
Geomotion also integrated external survey data into Geomotion Cloud, offering the client a centralised platform to view all data, enabling them to make quick and informed decisions.
Want to ensure the safety and reliability of your major property asset? Geomotion can help. Contact us today for an obligation free discussion on how our precision monitoring solutions can provide key information in real time to prevent costly and dangerous critical failures. Suitable for new construction and existing building monitoring.
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The Queen's Wharf development in Brisbane is a GLS Monitoring project involving Geomotion and Land Surveys.
The project, part of the redevelopment of the Queen’s Wharf Precinct into a new world-class integrated resort, includes full automation of existing monitoring devices, as well as the installation of additional instruments including:
The project includes a staged warning system during Maritime works as part of the construction management plan, as well as monitoring of key structures including the Riverside Expressway.
January’s fatal tailings dam collapse at Vale SA’s Corrego do Feijao mine has sent the global mining industry once again scrambling to check the integrity of its tailings management systems.
The January 26 tailings dam collapse at the Corrego do Feijao mine near the town of Brumadinho, in Minas Gerais, killed more than 300 people and came just four years after the Samarco tailings collapse in the same state became Brazil’s worst environmental disaster and also killed 19 people.
Brazi’s mining regulator ordered Vale to suspend operations at its Fabrica and Vargem Grande complexes immediately after the Brumadinho disaster.
In a statement, Vale said the mining regulator ordered the suspension in light of the possible failure of five dams at the mining sites in the interior state of Minas Gerais. Since then, both authorities and mining companies have stepped up scrutiny of so-called upstream dams, which have been subject to multiple high-profile failures in recent years.
In a statement, Vale said it was abiding by the regulator’s decision but was asking the body for permission to dismantle the dams, while continuing some operations at the mine, “which would bring about limited impacts on production”.
The miner did not offer an estimate on how much production likely would be lost. However, the company had previously planned to maintain operations at Fabrica via dry mining, which eliminates the need for upstream dams. The company estimated that plan would result in 3mt of lost production in 2019.
“The cost of the wireless monitoring makes more sense than a couple of employees driving around different locations, taking measurements every few months. It eliminates errors, increases safety in remote locations and reduces costs because it is less labour-intensive,” - Kim Malcolm, Geomotion
Minas Gerais is still recovering from the 2015 Samarco collapse which buried a village and poured toxic waste into a major river.
Vale chief executive Fabio Schvartsman said the dam that burst was being decommissioned and its capacity was about a fifth of the total waste spilled at Samarco.
Schvartsman said there had not been any recent construction around the dam and apologised without taking responsibility in a television interview.
“Apologies to society, apologies to you, apologies to the whole world for what has happened,” he said. “I don’t know who is responsible, but you can be sure we’ll do our part.”
The disaster prompted the world’s largest miners to announce risk reviews of their tailings facilities.
BHP Ltd, which was Vale’s JV partner in Samarco, said it had “significantly increased the rigour of its assessment and management” of tailings since 2015, including a risk review which resulted in more than 400 actions being assigned to company assets.
“These actions are 93% complete, with the remaining actions considered low priority such as administrative actions and long-lead items regarding closure and climate change impacts. None of these actions is overdue,” the company said in a statement on February 19.
Rio Tinto Ltd – which has 100 active tailing facilities and a further 36 closed or under rehabilitation – said its tailings facilities were subject to three levels of governance and assurance.
“In August 2015, Rio Tinto introduced a standard for management of tailings and water storage facilities in order to ensure all our managed facilities are operated in accordance with one global standard,” chief executive J-S Jacques said. “In light of this tragic event, Rio Tinto is again reviewing its global standard and, in particular, assessing how we can further strengthen the existing audit of facilities.”
Perhaps the most surprising aspect of the disaster is how late Vale was in recognising the dangers.
Schvartsman said equipment had shown the dam was stable on January 10 and it was too soon to say why it collapsed. However, according to Geomotion Australia managing director Kim Malcolm, modern instrumentation and software allow for real-time monitoring of tailings facilities.
“In the past it was prohibitive to have real-time monitoring because of all the cabling required but now wireless data loggers are readily available; there was never previously anything available that could do that,” he said.
Geomotion works with a number of major miners in Australia including Rio Tinto, South32 Ltd and Newmont Australia providing geotechnical and structural instrumentation and asset monitoring. Malcolm said the days of having just a few sensors on a tailings dam, intermittently monitored by hand were rapidly ending.
“The cost of the wireless monitoring makes more sense than a couple of employees driving around different locations, taking measurements every few months. It eliminates errors, increases safety in remote locations and reduces costs because it is less labour-intensive,” he said.
Software such as the Mission Monitoring operating system also allows companies to anticipate problems as well as alerting them to impending spills.
“It is less about the alarms but about the constant, real-time review,” Malcolm said. “It allows you to see the trends well before anything happens.”
The web-based software could also present opportunities for companies to better relate their tailings management to affected communities.
“The software is designed so alarms are set up on individual smart phones,” Malcolm said. “It allows companies to select who has access to the alarms and they can even present the monitoring data on open websites to ensure their management has a more public-facing interface.”
– Dominic Piper - Australia's Paydirt (March 2019)
In line with the current VIBRA-series, of which thousands are now in use worldwide, Geomotion partner, Profound BV, proudly introduce the new VIBRA+. Later this year the new standard VIBRA will also be available.
New features of the VIBRA+: