The future of underground mining at Carrapateena

Oz Minerals' Carrapateena site. Image: OZ Minerals

There is an important trend towards technological innovation in the mining industry as miners strive for greater safety, efficiency and productivity.

The opportunity is even greater for underground projects where the development and application of new technology, particularly sophisticated communications infrastructure, has been slower due to the challenging environment.

As technology has advanced, however, solutions such as automated loaders, semi-autonomous drills, various safety innovations and sophisticated communication systems are now being increasingly applied at underground projects around the globe with Australian mines among the early adopters.

Pybar Mining Services is taking the lead at the Carrapateena copper-gold project in South Australia by offering some of the latest innovations in support of OZ Minerals’ ultimate vision of the project becoming Australia’s first fully autonomous mine.

This vision strongly aligns with some of our values; safety, service and results, and our commitment to applying innovative technologies that deliver tangible benefits to our clients.

Following the on-schedule completion of the Carrapateena box cut development and portal firing at the end of September 2016, a number of innovative initiatives are now being rolled out during the development of the access decline.

Reducing risk at the face

While mine-wide surface support to the backs and walls of excavations has substantially reduced the risk of injury from rockfall, exposure to injury due to loose rock being dislodged from the drill face remains. This hazard is greatest when personnel are installing and charging lifter tubes.

As such, Pybar has commenced trials of a spray-on lining membrane, comparing various similar products from several manufacturers. The liner will secure any loose material on the face, providing a safer environment for drillers, nippers and chargehands.

While commonly used in general applications in the coal sector, its application as an alternative to meshing and bolting or shotcreting the face is a first for the Australian hard rock industry.

The product is easily applied to the face using shotcrete spray rigs and cures rapidly. Early results have been encouraging.

Improving safety and productivity

Wireless communication systems that track, schedule and communicate with personnel and machinery have revolutionised open pit operations.

Underground, however, has been a different story. Conventional Wi-Fi use has been restricted due to its cost, complexity, poor range and location accuracy of no better than 20m. Reporting and problem solving is typically retrospective rather than in real time and the solution to accurate tracking of tasks and equipment has proven to be elusive.

Now, the commercialisation of an effective and cost-efficient high precision tracking and communications technology has the potential to revolutionise underground operations.

Developed by an Australian mining ICT developer and supplier, the system enables sub-metre accuracy positioning to track and communicate with personnel and machinery underground in real time.

The infrastructure is powered by core wireless technology invented by the CSIRO, and is believed to be the only dual purpose communications system available globally with this level of capability in the underground environment.

While a number of Australian, and a few international mines, have partially applied this technology for tracking of equipment, we are one of only two mining contractors that have commissioned it for both tracking and data communications.

Our application of the technology at Carrapateena will see a phased roll out of the wireless communication and high precision tracking infrastructure and accompanying task management and safety platforms.

Wireless communication systems that track, schedule and communicate with personnel and machinery have revolutionised open pit operations.

Phase one will consist of a two-way underground digital radio system plus the installation of wireless infrastructure to cover the 500m to the decline face. A select number of our heavy and light vehicles will be fitted-out with the system’s mobile nodes and in-vehicle PCs, and set-up with the task management system. This will allow equipment to be visible to other enabled equipment in the work zone, reducing the risk of collision.

The system will allow real time communication and data transfer between supervisors and enabled vehicles and equipment, allowing performance monitoring and problem solving in real time, rather than post-shift.

Production information can be directly input to the reporting database by the operators, allowing supervisors and other operators to monitor progress precisely and to better prepare for the next critical-path activity, thereby increasing operational efficiency.

In the event of equipment breakdown, offsite electrical maintenance personnel can access the network to assist with diagnosis, parts, technical assistance and repair. No specialist technicians are required on-site.

It is widely accepted that without sophisticated communications infrastructure and platforms, autonomous mining simply isn’t achievable. As such, the system represents critical infrastructure on Carrapateena’s journey to autonomous mining.

Increasing drill rig safety

Initiatives for the continuous improvement of employee safety and well-being remain a core focus throughout the industry.

A known risk underground is the potential for entanglement in exposed rotating drill steels. While this risk is managed through safety procedures, technology is now available which can provide another layer of protection.

At Carrapateena, Pybar is retrofitting an advanced safety system to its two jumbos onsite. The system uses laser scanners to measure the location of people around the drill and automatically disables the functions of drilling and boom movement should anyone inadvertently pass into the operating zone in front of the drill rig.

Carrapateena will be one of the first mines globally to deploy the system.

With safety a core value, this is an important initiative for Pybar as we continuously seek to improve safety in the workplace.

Greater productivity

Carrapateena is a high-speed development project. Hence, the use of technology that facilitates increased development productivity is a core initiative.

Pybar is applying semi-autonomous technology to its LHD that allows for waste bogging to be undertaken while exhausting toxic fumes following a blast. By shortening the face cycle time, it is expected to deliver significant productivity benefits.

The system will allow autonomous navigation capability from the loadpoint to the stockpile within the low visibility area without any operator guidance. The system can steer the loader while engaged in up to fourth gear if the roadway is suitable, hence optimising the cycle time.

The operator can then switch to conventional tele-remote function for the more complicated activities of bucket filling and dumping at the stockpile. All video and data transfer is via a wireless network over a fibre optic backbone.

While the system is being rolled out to various sites across Australia, Carrapateena will be the first to apply the technology for development and stockpile application purposes.

Brendan Rouse is the chief operating officer for Pybar Mining Services.