4.14 Monitoring technologies

4.14.1 Real-time monitoring

Many mining operations use technology and communication platforms to operate their fleet of earthmoving equipment and their process plants. The use of telemetry networks for monitoring the environment is just an extension of this management technique. It saves the time and cost of manual data downloading and allows the monitoring staff to acquire information and act proactively, rather than reactively. The benefit is that the environment can be managed and operated in a similar manner to plant on the mine site. Telemetry networks can also provide cost savings by reducing the magnitude of the impact of incidents and the associated clean-up effort and by facilitating early intervention. They can also bring safety benefits and labour savings, as staff can limit visits to remote monitoring locations to maintenance inspections. The real value of data is realised when it is incorporated into the dataset and used to improve management.

When developing a telemetry system for a monitoring network, it is important to discuss requirements with a specialist. Apart from the immediate need to convey data from A to B, the design must consider the telemetry bandwidth, network support, communications protocol, power supply (preferably by solar panels, which are essential for remote locations) and consumption, data delivery, data storage, connectivity and data display.

Many system control and data acquisition (SCADA) packages for telemetry are programmed to store high-resolution data for only a short period—days or weeks—before the data is summarised. It is critical that the environmental data is stored at its original resolution before any summations are made. That being said, if the site SCADA package has the potential for environmental data transmission with the appropriate safeguards it can be of enormous benefit, as environmental staff will then have onsite support for back- end data receipt and management.

Leading practice requires the data to be delivered and accessible to the end user in a simple, usable format. This does not mean that the system has to have graphical displays; rather, it should deliver the data in a format that meets the program objectives. For example, some integrated GPRS (general packet radio service) data loggers can send an alarm out using voice messaging and SMS and an email of the dataset. This links field officers to their field instruments through smartphones. On the other hand, radio telemetry networks are normally site-based and have limited capabilities to transmit offsite.

To identify the appropriate technology, the project’s objectives should be considered and, as a minimum, the following questions should be addressed:

  • Is the data required in ‘real time’ for operational purposes or ‘almost real time’ for post-event management and alarm purposes?
  • What is the quantity of data to be relayed over the network? Does the selected technology have adequate bandwidth to both manage the immediate data transmission needs and allow for future expansion?
  • What infrastructure is in place that can be used for the telemetry network? Is the system to use site- based radio telemetry or publicly operated networks, such as mobile phone GPRS systems or satellite telemetry?
  • Is there a transmission charge, such as when using commercial networks for GPRS and satellite transmission?What communication protocols do the field instruments use and can the telemetry unit accept their input?
  • Has power consumption been considered?
  • What is the geographical coverage required? Has consideration been given to vegetation (signal attenuation) and topography)
  • Has climate been considered? Could heavy rainfall attenuate signals and cause signal loss? In hot climates, such as at arid or desert sites, can signals be distorted or blocked by heat mirages?
  • If using the site SCADA and telemetry system, what is the back-end SCADA package? Can data at the correct resolution be saved and exported? What data connection is possible to allow the export of data from the SCADA package in a simple, accessible format?
  • What requirements do the stakeholders have for accessing data?

The telemetry solution is not appropriate if the data is inaccessible or the data resolution is compromised by the telemetry platform. Field verification, calibration and maintenance are still required.

With rapid and constant change in technology, the demand to provide access to data now is growing. When designing a telemetry system, care must be taken not to leave out the data management requirements. The network will generate large amounts of data. At some time, false readings will need to be quarantined from alarms and dissemination to stakeholders. It is also important to ensure that the selected system has the ability to qualify the data either at the field monitoring station or by post- processing.

A leading practice telemetry system saves the environmental staff time, allows them to act on events in real time and is robust, reliable and cost-effective.

4.14.2 Routine and novel remote sensing

Aerial photography

Most open-cut mine sites have a standard set of remote sensing data that is collected on a regular basis to estimate resource and spoil stockpiles. Some of these data layers include annual site aerial photography (resolution ~50-cm pixels) and a photogrammatically derived digital surface model. Both these datasets tend to be underutilised by staff responsible for site rehabilitation. Because rehabilitation objectives require a safe, stable and sustainable landform, this remotely sensed data could be used to check the overall progress of a site. A time series of aerial photos illustrating the progression of rehabilitation, when compared to rainfall, soil and other data, may be used to help determine why some areas of rehabilitation have had more successful vegetation establishment. Areas of bare ground can be derived from classification of the aerial photography using GIS. For example, using iso-cluster analysis in ArcGIS, aerial photos can be used to demonstrate areas of bare ground across a site’s rehabilitation areas. Where the bare areas are persistent over time, this data can be used to guide soil surveys to determine whether there is an underlying substrate cause.

Slope angles of rehabilitation can be determined using the site digital surface model in GIS. If slopes are beyond suggested completion criteria or incompatible with the targeted post-mining land use, rework activities could be targeted, particularly where there is active erosion or unplanned ponding in geochemically active or risky material.

LiDAR

Airborne light detection and ranging (LiDAR) is commonly used to collected 3D point clouds of mine sites and is most cost-effective in more extensive areas, as long as good statistical analysis of the collected data can be done. LiDAR has the advantage that it collects multiple data points from rehabilitation vegetation and ground surfaces. If LiDAR datasets are available, the data from hard returns (for example, from the ground surface) could potentially be used over time to assess changes in the terrain beneath the vegetation and assess the development of gully erosion. Using change maps allows early intervention to prevent expensive and time-consuming earthmoving at closure. This dataset could also be used to illustrate the stability of a site’s rehabilitation before management applies for closure.

Unmanned aerial systems

The miniaturisation of sensors and the increased reliability of unmanned aerial vehicles (UAVs) controlled by GPS-guided autopilots allow the collection of hyper-temporal (several times a day) and very high resolution (~5-cm pixel) imagery across rehabilitation areas. This type of data can now be routinely collected by a number of organisations and, when processed, can generate highly accurate photogrammatically derived digital surface models of individual rehabilitation areas. Additionally, the imagery allows high-precision vegetation maps to be generated, particularly if landscape features and plant species are targeted and marked by ecologists before images are collected. One example of this technology becoming a routine part of vegetation assessment is at Curragh coalmine, where UAVs collect imagery with a resolution of ~5 cm to monitor ground cover, rehabilitation success and erosional processes over time. UAV imagery has also been used in combination with targeted ground surveys to map the distribution of a rare shrub species on mine leases in the Blue Mountains (Fletcher & Erskine 2012).

Thermal cameras operating in UAVs can be used to identify rehabilitation areas with subsurface fires and spontaneous combustion issues. They ensure that rehabilitation can be assessed where noxious gases (such as carbon monoxide and nitrous oxide) limit access and are a risk to human health. Monitoring conducted with UAVs fitted with sensitive gas sensors could be used to map and model gas plumes.

Finally, UAVs with thermal cameras can track animals that are using rehabilitation areas and provide evidence that sites have created native fauna habitat.

Smart sensor technology

In the past decade, there has been steady growth in smart sensor technology, and particularly rapid changes over the past five years. These technologies range from simple water-level sensors that have inbuilt data loggers and GPS units with centimetre accuracy to scanning technology using UAVs and remotely controlled bathymetry vessels.

The benefits of these technologies are readily apparent, such as the additional information that they can provide. It is more challenging to effectively manage the vast datasets that are captured and the additional computer processing power required to manage and analyse the data and generate the final product.

Leading practice using remote sensing technology considers the selection of the most appropriate instrumentation as carefully as more traditional monitoring. To identify the appropriate technology, the project’s objectives should be considered and, as a minimum, the following questions should be addressed:

  • Are the data required in real time for operational purposes or ‘almost’ real time for post-event management and alarm purposes?
  • What is the geographical coverage required? Has consideration been given to vegetation (signal attenuation) and topography?
  • What is the quantity of data to be captured?
  • What communication protocols do the field instruments use and what data formats will the field data be provided in?
  • What software tools and analysis skills are needed for data processing? What output requirements do stakeholders have?
  • How often should the study be replicated?
  • Is the data required in real time for operational purposes or ‘almost’ real time for post-event management and alarm purposes?

Remote sensing can provide excellent datasets that can be used to identify even minor environmental issues. Leading practice takes into account the resolution of the study for both data capture and interpretation.

4.14.3 Limits of detection for monitoring parameters

When choosing the detection limits for monitoring parameters, it is important to consider the reasons for collecting the measurements and the timespan over which the measurements may be used. Analytical methods tend to improve over time, and the levels of detection achieved tend to improve as detection limits decrease. Corresponding with this, target standards and guidelines also tend to reduce as community perceptions of acceptability tighten over time. It is true that the current standard commercial laboratory analytical methods are not able to detect all the toxicants in the Australian and New Zealand guidelines for fresh and marine water quality (ANZECC–ARMCANZ 2000a) at levels below the trigger values (silver is an example relevant to mining), but commercial analysis methods are approaching this as routine for most parameters relevant to mining.

For these reasons, it is important in the earlier stages of a project to aim for the lower range of detection limits that are currently achievable and at all stages to regularly reassess the levels of resolution that are requested of the analysis laboratory or specified for field or site monitoring equipment purchases, in order to maximise the relevance of the monitoring data over time. As mentioned in Section 4.10, monitoring data is often the most valuable asset of a mine’s environment section, and built-in obsolescence should be avoided as much as possible.

This may mean that consideration should be given to using ‘cutting edge’ or more costly analytical methods rather than standard, mid-priced commercial analysis, at least for key parameters and sites. The acquisition of pre-mining baseline data can never be done again once a mining project starts, so it is worthwhile to consider paying for low levels of detection at the initial stage, even if later routine compliance monitoring does not have such stringent requirements.

For some parameters, extremely low levels of detection are possible but might not be achievable by non-specialist personnel or laboratories. The sample preparation, collection, handling, shipment and analysis quality control requirements for measurement of, for example, dissolved metal concentrations in the nanogram per litre range (important for some elements in some circumstances) are much greater than for levels of detection in the low microgram per litre range (more typical for aquatic ecosystem protection for most metals), which in turn are much greater than for measurement in the upper microgram per litre and milligram per litre ranges (more typical for human drinking water considerations). The fact that a laboratory instrument has specifications indicating that it can achieve a particular level of detection does not mean that reliable measurements at very low concentrations can be achieved in practice without specialists being involved at each stage, from container preparation, sampling and delivery to the laboratory through to laboratory analysis and reporting.

This has become increasingly evident as a result of the improved availability of low-level analysis. While analysis to the required levels of resolution is readily available from the better environmental analysis laboratories, the skill levels of samplers and sample collection quality assurance and control systems to reliably manage contamination below these levels are not as readily available. Even the selection of the sampling equipment for these low levels of resolution requires careful consideration, and not all manufacturers are able to provide equipment of an adequate standard. For example, there are no commercially available water sampling poles that do not have metal fittings in the bottle-holding mechanism. Leading practice monitoring is able to achieve these levels of resolution and quality control and either has systems and training in place to ensure that they are achieved reliably or uses specialised consultants to achieve quality control of low-level sampling.

The key issue is that leading practice considers which analytical methods are appropriate for the project’s data needs, both now and into the future, and selects methods that are appropriate to those needs.

Leading practice never selects methods on the basis of current laboratory pricing structures and the skill sets of low-cost sampling personnel.

Collapsed - Case Study: Pushing technology to meet expected future requirement—Tampakan Project baseline water quality monitoring

The proposed Tampakan copper–gold project is located around 65 km north-north-west of General Santos City, a major growth centre on the southern Philippines island of Mindanao. The project area straddles a steep north-north-east trending incised plateau that ranges in elevation from 1,000 metres in the south to 1,350 metres in the north.

The Tampakan Project will be a large-scale copper–gold mine with a measured, indicated and inferred resource estimated in November 2013 to total 2.9 billion tonnes of ore at a grade of 0.5% copper and 0.2 grams per tonne gold and containing 15 million tonnes of copper and 17.6 million ounces of gold using a 0.2% copper cut-off grade.

The area is politically complex, and the deposit sits in the headwaters of seven different catchments, most of which are heavily used by downstream stakeholders for irrigating crops, stock watering and drinking and sanitary water supplies, and as a source of aquatic foods and other resources, all of which contribute to a need for rigorous, defensible baseline environmental data. In April 2007, Xstrata Copper (now GlencoreXstrata, XCu) acquired a controlling interest in the project; day-to-day management of the operation was through Philippines-based mining company Sagittarius Mines (SMI).

Until April 2007, surface water monitoring at Tampakan was conducted at 71 separate locations in more than 10 catchments. It was done periodically from January 1995, largely by Philippines-based consultants, and was consistent with the national requirements for environmental monitoring and assessment. XCu and SMI determined that there was a requirement for further feasibility studies and that a more detailed environmental impact statement would be needed to meet XCu’s international obligations. The project committed to an extended pre-feasibility stage to gather the necessary additional knowledge. A substantial extension of the baseline water quality monitoring program was part of that commitment.

The baseline water quality sampling and analysis program aimed to achieve leading practice by using rigorous quality control, clean trace-metal sampling techniques and then state-of-the-art analysis to low parts-per-billion levels. Laboratory analysis was initially sought from commercial environmental analysis laboratories in Hong Kong and Australia, both of which had a long-term history of high-quality environmental chemistry analysis for international mining projects. The water quality sampling was conducted under the stewardship of an Australia-based environmental consultancy. As a due-diligence exercise, initial rounds of the renewed sampling and analysis program included multi-element ‘scans’ of 70 elements to identify any unusual elements of concern. In addition, ultra-trace metals analysis was conducted in the initial two sampling rounds, as both a baseline data collection and a sampling program design assessment measure. As part of ongoing support and capacity building for local Philippines laboratories, analysis for selected parameters was undertaken at national environmental analysis laboratories on sample splits sent to the international laboratories for interlaboratory comparisons. It was intended to use Philippines laboratories in preference to international laboratories if suitable quality control and assurance could be established through cooperative capacity building.

SMI Environment Department staff were trained by international consultants in conducting water monitoring to high levels of quality control and assurance. This included requiring all laboratory parameters to be within 15% relative difference for triplicate samples taken during each monthly sampling round and field blanks to be below reporting limits.

The result has been two years of monthly and quarterly (depending on sampling site location) baseline water-quality monitoring data of high quality. The data is expected to provide a sound dataset that will be useful for the multi-decadal life span of the project. This has included achieving reliable trace metal analysis results to sub-μg/L levels of resolution. Such a high-quality and extensive baseline dataset was well beyond the minimum requirements for the pre-feasibility stage of a mining project in the Philippines, and in terms of data quality, levels of resolution and quantity, beyond the typical international requirements. However, SMI and XCu considered it to be of substantial benefit to the project because it would serve as a defensible baseline for many years, provided high-quality inputs into environmental management planning for the project and provided skills training to international leading-practice standards for in-country staff and service providers.

Since 2009, the project has remained undeveloped, but laboratory analytical capacity has improved such that ultra-trace metal analysis is now routinely offered by the better equipped environmental analysis laboratories. However, the limits of detection offered have not reduced markedly and the limits of resolution of the Tampakan baseline sampling remain relevant and leading practice.

Greater experience in the use of ultra-trace limits of resolution of analysis by a broader number of monitoring teams has found that quality control of the sample collection and handling is now commonly the limiting factor in determining practical limits of resolution for metal concentration because of sample contamination at those low concentrations, not because of laboratory instrument detection limits. Therefore, the effort put into training staff in quality control of sample collection by Tampakan, and the incorporation of good-quality assurance protocols including the routine use of trip and field blank samples, were particularly important and provided the project with a robust baseline.

Bottles used for sampling
Bottles used for sampling.

Filtering for dissolved metals and measuring flow
Filtering for dissolved metals and measuring flow.

Flow in the Dalul being diverted into the irrigation channel
Collecting water samples.

Collecting water samples
Flow in the Dalul being diverted into the irrigation channel.

Irrigation channel
Irrigation channel.

Local woman washing vegetables
Local woman washing vegetables.

4.14.4 Leading practice fauna monitoring methods

General considerations for fauna monitoring are outlined in the Biodiversity management handbook (DIIS 2016f). Monitoring methods have continued to evolve, and a number of recent technological improvements are now routinely used in fauna monitoring at mining operations. They include automatic audio recorders for bats, frogs and birds. A number of different types of auto recorders are now commercially available and are relatively inexpensive. They allow for sample monitoring day and night and for extended periods. Audio recorders used in conjunction with voice recognition software have considerably improved cost- effectiveness in data collation and analysis. For example, vocal recognition using computer identification of species has been used successfully for the detection of threatened species. The cost-effectiveness of audio recording enables the processing of considerably more data and improved monitoring quality. Other benefits associated with audio recording include:

  • removal of observer bias
  • rapid collation of biodiversity present
  • weatherproof construction and long battery life, allowing for extended periods of monitoring
  • consistency when repeating surveys
  • increased information gathering (for example, threatened and cryptic species detection)
  • cost-effective increase of sampling frequency (to enable seasonal sampling)
  • electronic generation of data, allowing for reanalysis at a later stage, verification of data quality and ease of storage
  • concurrent monitoring (that is, surveying a number of locations in the same point in time)
  • simplicity of use.

Infrared and motion-detection cameras are now commercially available and frequently used to survey fauna at mining operations. Such cameras enable day and night monitoring of discrete locations, such as water bodies, heap leach pad ponding and tailings systems. Where wildlife mortalities occasionally occur, they are very useful in carcass detection and, more importantly, in detecting carcass removal by scavenger species.

Although automated fauna monitoring technologies are readily available and now widely used, an understanding of the monitoring requirements, target species and how the technologies work is critically important for data integrity and subsequent analysis. For example, territorial species can be detected more frequently within their range using camera traps, and vocal birds are more readily detected with audio devices.

Abundance comparisons between species or even between age classes of a species are often not valid; such camera and audio devices typically measure species activity, not abundance. However, they are good at detecting rare, nocturnal and cryptic species.

Due to expense, fauna surveys are often conducted annually, usually at the same time of year to remove seasonal bias. Data analysis is used to determine any changes from the previous year. That might not be satisfactory, since impacts to wildlife may occur and remain undetected until the next annual survey. The cost-effectiveness of audio and camera surveying can enable quarterly or continuous monitoring at a similar cost to typical monitoring techniques. Importantly, the increase in frequency of sampling improves the timing and extent to which changes are detected.

Collapsed - Case study: Fauna monitoring to assess offsets and mine rehabilitation

Glencore’s Mt Owen Mine is in the Upper Hunter Valley of New South Wales. The original 1994 mine development consent permitted the disturbance of 240 hectares of Ravensworth State Forest, while in 2004 a development authority allowed for the clearing of a further 94 hectares of the forest, subject to the implementation of a biodiversity offsets strategy including comprehensive flora and fauna management measures.

Ravensworth State Forest is a highly significant remnant on the local and regional scale, and is one of the largest remaining areas of woodland on the Hunter Valley floor. Impacts on flora and fauna are managed under the 1994 Mt Owen Mine Plan of Management for Revegetation and Wildlife and subsequent revisions. Together with the biodiversity offset strategy, the plan requires conservation values in areas of remnant woodland to be managed and protected, restoration and reafforestation to be carried out on degraded and cleared areas, and targeted mined areas to be rehabilitated to woodland communities. The fauna monitoring and management programs are reviewed annually by the Mt Owen Flora and Fauna Interagency Advisory Group, which comprises representatives from the Department of Resources and Energy, the Hunter Environment Lobby, the University of Newcastle and the Mt Owen Complex (MOC).

Management actions to restore and enhance habitat for protected and threatened fauna include the permanent exclusion of grazing stock, modifications of water bodies to enhance habitat value, the installation of 300 nest boxes for hollow-dependent species in remnant, restored and rehabilitated woodland, the establishment of native woodland in offset and rehabilitated mine areas, the collecting and spreading of forest debris such as logs in rehabilitation, weed management, and feral animal control.

Flora and fauna monitoring are critical components of this management. An annual fauna monitoring program includes monitoring of both the effects of mining activities on fauna in remnant areas and the recovery and recolonisation of fauna in restored, reafforested and rehabilitated areas. This provides information essential for understanding the habitat requirements of fauna and enables the development of the most cost-effective techniques for promoting fauna recovery and recolonisation. Monitoring data is compared across three forest sites, four regenerating (restored or reafforested) sites, and two sites in mine rehabilitation areas. The fauna monitoring program is described in detail in FFSNI (2013).

Leading practice terrestrial vertebrate fauna survey techniques have evolved considerably in the past 10–15 years. Those used at MOC include conventional procedures and recently developed survey methods, including:

  • conventional bird surveys (such as visual and bird calls) and mammal trapping
  • pit trapping for reptiles, frogs and small mammals
  • using infrared (heat) and motion-detection cameras to detect several feral fauna species (such as wild dogs and spotted-tail quolls
  • using other cameras for waterbird population counts on wetlands, for population estimates of larger mammals, and to document stock intrusions
  • nest boxes that are checked using a camera mounted on a pole, which overcomes working-at- height restrictions and is a cost-effective alternative to trapping and spotlight surveys
  • using harp traps and Anabat detectors to survey bats
  • radio tracking of the spotted-tailed quolls using GPS collars and remote data retrieval via telemetry.

The project has helped to identify specific quoll habitat requirements, and also opportunities to improve habitat for the species, in the rehabilitation and revegetation areas of Mt Owen.

Several other recently developed vertebrate fauna survey techniques are used effectively in leading practice fauna surveys at other mines in Australia, but were not considered appropriate for the specific habitats and circumstances at MOC. They include song meters, which enable the passive monitoring of several faunal groups, including microbats, birds and frogs. They are also suited to long-term monitoring of several rare and cryptic species that would otherwise require intensive field hours by staff at considerable expense. They enable sampling during specific times of the day or during events such as summer storms when activity peaks for some species.

Fauna monitoring results at MOC have shown that colonisation of rehabilitated areas by vertebrate species, including a range of woodland birds and bats, is progressing well (for details, see FFSNI 2013). The rate of colonisation for some species has been enhanced by the installation of critical resources, such as rock and timber piles, frog ponds and nest boxes. However, as has been found elsewhere, there is variability between species as they recolonise rehabilitated and reafforested areas at different rates according to their habitat requirements.

The MOC fauna monitoring program is a useful illustration of how leading practice flora and fauna monitoring and management programs can be used to help mines achieve biodiversity conservation, offset and rehabilitation objectives. More details of these programs are in Glencore (n.d.), which includes several relevant publications.

Spotted-tailed quoll radio-tracking
Spotted-tailed quoll radio-tracking study.

Australian owlet-nightjar
Australian owlet-nightjar.

Bats in boxes
Bats in boxes.

4.14.5 Other technology considerations

Many leading practice monitoring methods have been or are being developed to meet particular needs. They include methods such as:

  • improved sensor technologies, including biosensors
  • specialist remote sensing methods:
    • on land, such as high-resolution satellite imagery of varying wavelengths and combinations of wavelengths
    • on water, such as hydro-acoustic sampling of aquatic organism position, density and size frequency; acoustic Doppler current profiling of water and suspended sediment movements; acoustic, including sonar, habitat mapping systems; automated video habitat and organism recording systems (for example, BRUVS or baited remote underwater video systems for fish); and water-quality drones
    • in the air, using remotely operated low-flying UAVs carrying cameras and multispectral detectors (Section 4.13.2)
  • improved non-destructive animal sampling, such as frog recorders, bat detectors and DNA analysis of hair
  • tube samples
  • radio and satellite fauna tracking devices to assess habitat recolonisation
  • instruments for measuring water uptake in vegetation.

Importantly, leading practice monitoring does not select standard default technologies or cutting-edge technologies because they are cheaper or provide cachet. Leading practice uses technologies that are appropriate to the monitoring program and address both its immediate and future data needs. In many cases, the pursuit of leading practice may accelerate the development of these technologies as a result of their adoption by the industry.

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