Media Alert: Low-level helicopter flights to image geology over parts of Montana, Idaho

RESTON, Va. - Low-level helicopter flights are planned over a broad region in Idaho and Montana to image geology using airborne geophysical technology. The survey will be conducted from July 2024 for approximately 5 months, weather and wildfire restrictions permitting.

Surveying may resume in the spring or summer of 2025 if data collection is not completed in 2024.

Flights will cover areas of Idaho in Bingham, Blaine, Bonneville, Butte, Clark, Custer, Jefferson, and Lemhi Counties; and Montana in Beaverhead, Deer Lodge, Madison, Silver Bow Counties.

The flights are slated to fly out of Idaho Falls, Hailey, Challis and Salmon, Idaho. The survey base and flight locations are subject to change with little warning to other parts of the survey area as necessary to minimize ferrying distances and avoid adverse flying conditions

The purpose of the survey is to provide images that expand the fundamental knowledge of geology underpinning the Great Falls tectonic zone and Montana-Idaho Porphyry Belt. The area of interest covers numerous focus areas that are prospective for critical mineral resources and is designed to assist with the mapping of subsurface faults for earthquake hazard studies.

The survey footprint was coordinated with the Montana Bureau of Mines and Geology and the Idaho Geological Survey. Funding by the Bipartisan Infrastructure Law has facilitated coverage of such a large area.

The new geophysical data will be processed to develop high-resolution two and three-dimensional representations of bedrock composition and structure to depths more than 3,280 feet (1 kilometer) below the surface.

The 3D models and maps are important for improving our understanding of critical mineral resource potential, water resources, groundwater pathways near legacy mining areas, parameters for infrastructure and land use planning, and potential risks of naturally occurring radon.

Two helicopters will fly along pre-planned fight paths relatively low to the ground at about 300 feet (100 meters) above the surface. The ground clearance will be increased to 1,000 feet (300+ meters) over populated areas and will comply with Federal Aviation Administration (FAA) regulations. Flights will follow east-west lines spaced about 650 feet (200 meters) apart and north-south lines about 6,560 feet (2 km) apart.

The USGS is contracting with Dewberry and Sander Geophysics Ltd. (SGL) to collect data.

The survey will use helicopters equipped with an elongated "stinger" mounted to the underside of the cabin extending forward of the aircraft. Instruments in the stinger and inside the cabin will measure variations in the Earth's magnetic field and natural low-level gamma energy created by different rock types.

The scientific instruments on the helicopters are completely passive with no emissions that pose a risk to humans, animals, or plant life. No photography or video data will be collected. The data collected will be made freely available to the public once complete. The aircraft will be flown by experienced pilots who are specially trained and approved for low-level flying. The company works with the FAA to ensure flights are safe and in accordance with U.S. law. The surveys will be conducted during daylight hours only.

The survey fits into a broader effort by the USGS, the Montana Bureau of Mines and Geology and the Idaho Geological Survey and many other state geological surveys and other partners, including private companies, academics and state and federal agencies to modernize our understanding of the Nation's fundamental geologic framework and knowledge of mineral resources. This effort is known as the Earth Mapping Resources Initiative, and it includes airborne geophysical surveys like this one, geochemical reconnaissance surveys, topographic mapping using LiDAR technology, hyperspectral surveys, and geologic mapping projects.

To read more about this project and others, visit our newsroom.

More information about the USGS Earth Mapping Resource Initiative (Earth MRI) can be found here. To learn more about how the USGS is investing the resources from the Bipartisan Infrastructure Law, visit our website. To learn more about USGS mineral-resource and commodity information, please visit our website.