Deep hydrogen over Oyu Tolgoi, years before its discovery
Satellite imagery taken in 2000 shows a deep hydrogen anomaly sitting directly over one of the world's largest copper–gold systems, three years before it was officially discovered.
The challenge
Oyu Tolgoi in Mongolia's South Gobi is one of the world's largest copper–gold systems, but four of its six orebodies lie more than 300 m deep. We wanted to know whether gas escaping up the faults above such deposits could be mapped from space, and whether it would have pointed to Oyu Tolgoi before anyone drilled it. This was our own retrospective test, not a client project.
Our approach
We took a completely cloud-free ASTER shortwave (SWIR) scene from May 2000, three years before the official discovery, and processed it with our proprietary gas-detection algorithms. We focused on the "deep hydrogen" solution, because major fault zones cut the deposit and give gas a path to the surface, and mapped hydrogen anomalies across a district-scale area of more than 11,000 km².
The result
Several significant deep hydrogen anomalies appeared across the district. The most prominent lies directly over, and parallel to, the Hugo Dummett orebody along the Central fault, and continues south to the area just east of the present-day open pit. Combined with alteration mapping, hydrogen detection gives a powerful vector to large concealed mineral systems, and the same method is used to target natural hydrogen itself.
- MAY 2000Cloud-free ASTER scene captured
- 2003Oyu Tolgoi officially discovered
- TODAYAnomaly matches the mine and orebody