By John Carr and James Earl
Perspectives from a senior technical specialist and a production engineer at Newmont Boddington Gold Mine.
Newmont Fleet Management Services now continually monitors and plots the performance of JPS Locata alongside traditional GNSS in an effort to fine-tune the installed infrastructure. Learning to sculpt the perfect network continues as we move our JPS LocataLite transmitters to accommodate an ever-changing and expanding pit design.
Large twelve-meter benches and an aggressive mining plan have seen both North Pit and South Pit at NBG rapidly increase in depth, bringing the problems associated with GPS coverage in a deep-pit environment.
As mine sites develop and evolve, for the first time ever, we have the ability to dictate and control which areas we direct our own positioning coverage, and guarantee we can sustain accurate high-precision navigation wherever we need it. This level of control has just never been available before, and is literally impossible with satellite-based positioning signals. With GPS you just get what you get.
We are rapidly re-evaluating what may now be possible. We believe we are only at the very beginnings of where we can go with the LocataNet in the mining environment.
Staying One Step Ahead. Shape changes from week to week keep operations continuously relocating around the mine benches; this can, in some instances, make optimal positioning of the Jps LocataNet challenging. In the early stages of the project, we relied on producing computer-generated radio-coverage heat-map models of the pit to determine optimum positions for the individual LocataLite transmitters on the pit rim, and this is still a valid path if given the time.
However, with more Jps rovers becoming available, we now tend to make highly accurate predictions about network configuration on the fly. We can now install spare rovers as portable units in light vehicles (LVs) used by technicians onsite. This roaming functionality allows use of the Jps web browser in the rover to instantly validate, in the pit, any changes that may be required for the network before drilling and digging equipment is moved into place. Thus we can monitor real-world signal conditions in specific areas and adjust LocataLite positions to optimize positioning availability for machines that will soon arrive.
The typical network monitoring scenario nowadays is to quickly move a JPS-enabled LV onto a bench or area yet to be drilled or excavated, and review the signals from the individual LocataLite transmitters in real time. Technicians then make any necessary placement changes to the network in advance of any mining equipment arriving. Our ability to now ensure maximum possible positioning and navigation coverage at all times was undreamt of even 12 months ago.
Dual Rover. A modified HP Leica Drill JS System utilizing a Dual Jps Locata Rover has been installed into the drilling supervisors’ LV wagon. The drilling superintendent and supervisors had been exploring ways of moving towards a paperless system that could not only check the drill pattern itself, but also the areas being mined around the pattern. They identified a use-case example where having accurate positional information available in a vehicle enables supervisors to quickly review the construction and positioning of the protective windrows around the drill patterns. Access tracks and bench heights could also be checked without needing to call surveyors in to help. This degree of instantaneous clarity removes the guesswork associated with windrow construction, designed to provide a safety barrier between trucking and drilling operations. Incorrectly placed windrows can lead to potential flow restrictions in either operation, so getting it right the first time in active areas is important.
Mark-up by Night. Drilling supervisors can now accurately measure and monitor progress across the drill patterns using Locata technology to display virtual maps of all active drilling areas. Another spin-off benefit has been the introduction of a fixed point mounted to the front vehicle bullbar, to provide emergency mark-up of patterns during the nightshift when surveyors are not available on site. This helps particularly when a localized Wi-Fi outage prevents drills from downloading the blast pattern to commence drilling operations in an area of the mine. Before Jps, use of this high-precision GPS technology in vehicle had been considered ineffective and impractical because of the unreliable GPS coverage in the bottom of both pits. Plans are now under way to install a similar system into the shovel and auxiliary supervisors’ vehicles.
Forward! Recent group discussions found consensus that the best way to move forward with this technology now is continued integration into GPS, rather than stand-alone systems. Miners are generally a cautious lot: we could hedge our bets through a combined GPS+Locata solution package. Full-scale integration of Locata technology into future standard GPS products is perceived as a way companies such as NovAtel can provide the total package. We envisage a unified system available from all positioning receiver manufacturers that combines the benefits of GPS technology with the evident improvements and back-up that Locata has provided for environments where GPS is unable to function.
We have been in the enviable position of gaining a glimpse into the future, when the power of GPS-style positioning is improved to fill the GPS holes. The results we have obtained are, frankly, addictive. Having experienced this revolution first-hand, it would now be extremely painful to even contemplate going back to our previous GPS-only world.