Engineering News and Mining Weekly
Fibre optic cables improve monitoring, safety
Innovative applications of fibre optic cable technology can provide a proactive solution to detect potential risks associated with tailings storage facilities (TSFs) and improve protection of the associated environment, thereby vastly improving monitoring of the sensitive assets, reports test and measurement solutions specialist TANDM.
With a focus on enhancing leak detection, strain monitoring and TSF security measures, TANDM’s technology improves TSF management efficiency and safety in the mining industry.
The use of fibre optic cables in TSFs is increasing owing to the solution’s versatility, as well as the depth of information it can provide for TSF monitoring purposes, says TANDM lead engineer Stewart Chaperon.
A key feature of fibre optic cables is their ability to monitor and measure strain.
Depending on the location of such cables, they are also able to provide various other forms of data. Therefore, he says, TSF operators can choose a fibre optic cable option that meets their specific requirements.
Fibre optic cables can be placed in several places in and near TSFs, including below the high-density polyethylene (HDPE) liner, above the liner, around a tailings dam or inside a tailings dam.
When placed under the HDPE liner early in the construction phase of a TSF, fibre optic cables can be used to detect leaks and monitor temperature changes underneath the liner, thereby identifying any anomalies to be addressed through follow-up measures.
When placed on top of the liner, the cables are placed in a grid pattern over the liner, enabling such a deployment the ability to provide an indication of any ground movement, settlements or foundation instabilities.
Through doing so, the fibre optic system can assist in mitigating risks such as sinkholes, which could jeopardise the integrity of a TSF, the nearby mining operation and nearby communities.
As TSFs are filled with material as mines progress, fibre optic cables can be installed around or within the deposition of tailings to enable realtime monitoring movement and facilitate early detection of any structural instabilities.
Further, monitoring pipelines, which are critical for transporting tailings and wastewater, can also be enhanced through the use of fibre optic cables.
Distributed acoustic sensing (DAS) technology uses fibre optic cables to provide acoustic sensing, enabling early detection of leaks along pipelines to safeguard against environmental contamination.
“DAS technology is a very effective way of monitoring an entire pipeline. Operators can monitor up to 80 km of pipeline with a single fibre optic cable,” says Chaperon.
He adds that remote wirelessly-controlled pressure monitoring systems can also be deployed at different locations along a pipeline to detect blockages in the system, detect anomalies in pipeline pressure and provide early warning. This further reduces the risk of bursts and leaks.
Improved Security
Chaperon notes that a significant challenge impacting TSF operators is that TSFs are located in remote areas, resulting in increased security risks, particularly equipment theft.
He asserts that a key advantage of fibre optic cables is their requirement to be buried, which lowers their theft risk.
Further, acoustic fibre optic cables are able to detect various movements and activities in the nearby vicinity, which can alert operators of unauthorised access and potential threats.
Positioning the fibre optic cable beneath the surface, within about 30 cm of a TSF, effectively offers the ability to monitor movements such as pedestrian traffic, vehicular movement and excavation activities.
“It can even detect instances where individuals exit a vehicle and move away from it,” Chaperon explains.
The acoustic resonance technology also serves as a security probe, enabling the distinction between different types of activities occurring above ground, including monitoring for any unauthorised digging activities near pipelines or within the dam area itself.
Meanwhile, to offer advanced solutions capable of data acquisition and analysis through deep learning algorithms, TANDM has partnered with monitoring systems manufacturer Uptech Sensing.
As a result of the partnership, TANDM’s systems are able to collect data and interpret it to a greater degree, enhancing the systems’ intelligence. Essentially, operators can then extract insights directly from the fibre optic cable system, eliminating the need for extensive post-processing, states Chaperon.
Compact Solutions
He highlights that innovations in battery and instrumentation technologies have resulted in significant advancements in compact units that provide realtime monitoring.
Chaperon asserts that by implementing a monitoring system that extends beyond the visible external layer of TSFs, and instead incorporating sensors positioned at various depths beneath the surface, operators can ensure proactive management of TSF operations.
Compact units are able to address the root causes of failures in TSFs by detecting failures below the surface before they become visible on the external walls of the tailings dam. This is especially critical during TSF remining operations, where altering the stability of the dam by adding or removing liquid can pose significant risks, he says.
Further, TANDM units offer extended battery life and are capable of transmitting signals at frequent intervals.
Additionally, the units are designed to be discreet, reducing the risk of attracting unwanted attention or compromising security, Chaperon concludes.