GPS+GLONASS Technology at Chuquicamata Mine, Chile

Héctor Contreras

Abstract:	Chuquicamata mine is the largest open pit copper mine in the world. Located in the Atacama Desert in northern Chile, the driest desert in the world, at an altitude of 3000 meters, Chuquicamata mine has a 6km by 4km pit with a depth of 800 meters. Chuquicamata produced 650,000 tons of fine copper in 1997. The engineers of Chuquicamata have been involved in studying the development of GPS technology in mining applications. They were testing GPS receivers from the very early stage of development, when there was too few GPS satellites to get satellite coverage inside the pit. So that problem was one of the main concerns about GPS. Also, at that time there were only post-processing techniques, which in productive environments made the system inefficient. Finally, when real time techniques and a full constellation of GPS satellites were developed, it was thought that the problems would be solved. But the depth of the pit did not allowed to have full spatial and time coverage. Mine operations can not be dependable on when there will be enough satellites to work: the job has to be done any time, anywhere in the mine. Enough satellites to work accurately and effectively with GPS RTK means six or more satellites. Inside the pit and close to a wall there are few moments where this condition can be met. Secondly, it was noticed that double frequency GPS receivers are sensitive to loss of lock of the L2 signal in comparison with L1. In other words it is advantageous to add more observables adding more L1 signals from extra satellites instead of adding a weaker L2 signal from the same satellites. When Ashtech developed a receiver, which can use all the satellites in view, GPS and GLONASS, there was a big interest in testing this technology in the Chuquicamata pit. Thanks to this scenario, Chuquicamata took the decision to incorporate to its surveying operations Ashtech GPS+GLONASS RTK receivers. This is the first step. Next step is to install GPS+GLONASS RTK in Drills and Shovels for machine control, where there is a more demanding solution yet. To date, the system has been fully operational for more than six months, giving a very good solution today in surveying with a satellite positioning system in a mining environment like Chuquicamata. Still an optimized performance is expected with a full GLONASS constellation.
Published in:	Proceedings of the 11th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1998) September 15 - 18, 1998 Nashville, TN
Pages:	993 - 996
Cite this article:	Contreras, Héctor, "GPS+GLONASS Technology at Chuquicamata Mine, Chile," Proceedings of the 11th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1998), Nashville, TN, September 1998, pp. 993-996.
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