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Mining, Exploration and Geoscience

Cobar

MinEx Cooperative Research Centre (MinEx CRC) activities will be focused across the greater Cobar region (see map below).

Location map of the Cobar MinEx focus area

Location map of the Cobar MinEx focus area.

Current activities

Geological mapping and sampling

Geological mapping and sampling of rock outcrops in the Cobar area has been ongoing since 2020. The data acquired is being analysed and synthesised and will become gradually available through the NSW Seamless Geology dataset (also available on MinView).

A GS report was published on mapping updates (up to December 2021) in the South Cobar area.

A GS report was published with new chronological data for some rock samples in the Cobar region.

Further geological mapping and sampling of rock outcrops and existing drill core is planned in the Cobar region in 2023.

Cobar-Yathong seismic survey

A seismic survey has been planned to better image major faults in the Cobar area and the geometry of the Cobar Basin. This is a type of ground-based geophysical survey that is low impact. Seismic surveys help to build an image of the geology under the ground. Vehicles move along a route and generate energy vibrations that penetrate the ground and bounce off buried rocks. The reflected energy is recorded by a series of sensors.

Following roads, fire trails and existing farm tracks, no clearing of vegetation or soil will be necessary for the survey. Disturbance to traffic, residents, livestock and wildlife will be minimal. Two or 3 small trucks will transfer sound energy to the ground and will be supported by small vehicles for equipment, communication and personnel. Once the survey is complete, all equipment is removed from the site.

Map showing possible seismic lines:

Map showing planned possible routes in blue and follow roads or established tracks

Three lines will be surveyed. Two cross the northern part of the Yathong–Ivanhoe Trough, which will help map deep groundwater resources for a groundwater project. Continuing eastward the lines cross the Cobar Basin.  Data over this area will be used to better understand the rocks underground and mineral systems in the region. The survey will take around 6 weeks to complete, weather permitting.

Community information sessions

The Department of Regional NSW's Geological Survey has prepared an online information session about the Cobar AMR survey. A recording of the webinar is available here:

Remote video URL

Cobar MinEx CRC airborne magnetic and radiometric (AMR) survey from DPIE Training & Education on Vimeo.

You can also find out more about the AMR survey process here.

Completed activities

Hydrogeochemistry

Water sampling was conducted in May to September 2019 across the greater Cobar region. 86 samples were collected from existing waterbores then analysed for a range of elements and parameters such as salinity and pH. The age of some of the water samples was determined. Results were forwarded to landholders in May 2020 and are available on MinView. To download the data, click Tools > Data download > Hydrogeochemistry.

An accompanying interpretive report (by CSIRO and Geological Survey of NSW researchers) was released in March 2021.

Cobar Airborne Electromagnetic (AEM) Survey

GSNSW and Geoscience Australia coordinated an airborne electromagnetic (AEM) survey to measure the natural electrical properties of rocks and soil to a maximum of 400 m deep in the Cobar–Lake Cargelligo area. These properties vary depending on the type of rocks and soil, and the water content and salinity. The information collected will improve our knowledge of the geology and groundwater resources of the area, which will inform mineral explorers and farmers.

New Resolutions Geophysics (NRG™) was contracted to undertake the survey. A helicopter flew at a height of 60 m, with the sensor suspended 30 m below, along 116 east–west lines. The lines were typically about 55 km long and between 2.5 km and 5 km apart. An interactive map of the survey lines is shown below.

The data has been processed and is publicly available. If you are interested in receiving a copy of the data please email us at minex.crc@planning.nsw.gov.au. The data is also available from MinView.

GS report & data package – Cobar AEM Survey interpretation

We would like to thank the local community for their support.

Cobar Airborne Magnetic and Radiometric (AMR) Survey

Department of Regional NSW's Geological Survey with Geoscience Australia coordinated an AMR survey over the greater Cobar and Nyngan region.

AMR surveys measure small variations in Earth's magnetic field caused by different rock types and the naturally occurring radiation coming from the ground. AMR surveys use passive sensors, are non-invasive and do not disturb the ground.

The survey has filled gaps in our existing coverage, and the information collected will improve our knowledge of the rocks, faults, soils and mineral resources of the area.

GPX Surveys was contracted to undertake the survey. A plane flew 60 m above the ground along east‒west-oriented lines spaced 200 m apart. Some lines were flown north-south to 'tie' the data together. The plane flew higher over towns and buildings and tried to avoid groups of stock. Some areas were flown with a closer line spacing as industry-funded infill.

A map of the survey area is shown below.

The data is available for download from NSW Government's on-line application MinView. Industry infill data will be available publicly in the second half of 2022 through MinView.

AMR survey area (Download kmz file)

Cobar Basin mineral systems and drillhole data

Work by the GSSNSW has generated new data and interpretive products of mineral systems in the Cobar Basin:

3D geological models

New 3D geological models for parts of the Cobar Basin (based on AEM, drillhole and waterbore data and other assets) have been released:

Community information sessions

The Geological Survey of NSW held free drop-in sessions for landholders and the wider community in Cobar and Lake Cargelligo in April 2019.

Community-image-Cobar

Other publications and presentations