In 1994 the Lightning Ridge Mining Board determined that the title ‘Preserved Fields’ would be applied to older mining areas which would not be returned to their previous land use, adopting less strict rehabilitation standards.

The Geological Survey of NSW developed a Seamless Geology of UTM Zone 56 during2014 as part of a project to develop a seamless vector geology dataset of the best available geological mapping data covering the whole of NSW.The overarching aims of the Statewide Seamless Geology Project were to: (i) compile the different original scales, formats and rock unit naming conventions into a consistent, statewide format; (ii) edge-match the geology across existing map sheets; and (iii) interpret the basement geology under cover. The resulting geodatabase comprises a series of layers which include: (i) solid basement geology; (ii) cover rocks (defined as undeformed and unmetamorphosed); (iii) Mesozoic igneous rocks; and (iv) Cenozoic sedimentary and igneous rocks. The project was divided into 3 major stages corresponding to the UTM zones which divide New South Wales. This dataset includes the seamless geology layers from the NSW portion of UTM Zone 56 (ie.east of 150 degrees longitude to the coast).

Location of opal fields in Lightning Ridge, NSW.

The petrophysics database contains petrophysical (rock physical properties) data managed and acquired by the Geological Survey of NSW (GSNSW). Petrophysical properties recorded are: magnetic susceptibility (volume normalised); principal axes and degree of anisotropy of magnetic susceptibility; natural remanent magnetisation (NRM) intensity and direction; remanent magnetisation component directions; Koenigsberger (Q) ratio; saturated density; dry density; grain density; porosity. Vector and tensor magnetic properties (remanence and AMS) are oriented to in-situ (geographic) and fold-corrected (stratigraphic) coordinates where sample and bedding orientation are known.

Depth contours derived from the NSW Basement Elevation Model.

The NSW Seamless Geology Project is a five-year initiative of the Geological Survey of New South Wales which commenced in late 2013 and aims to provide a statewide compilation of the best available digital geological mapping data in an internally consistent format. The overarching aims of the NSW Seamless Geology Project were to: (i) compile the different original scales, formats and rock unit naming conventions into a consistent, statewide format; (ii) edge-match the geology across existing map sheets; and (iii) interpret the basement geology under cover. The resulting geodatabase comprises a series of layers which include: (i) solid basement geology; (ii) cover rocks (defined as undeformed and unmetamorphosed); (iii) Mesozoic igneous rocks; and (iv) Cenozoic sedimentary and igneous rocks. Due to the size of the project, the work was divided into UTM zones, starting in the east with Zone 56, then moving west to Zone 54, and finishing with Zone 55. The western half of Zone 55 was completed in 2018, after which the results were merged with the previously completed Zones to produce version 1 of the NSW Seamless Geology dataset. Completion of this stage saw the end of phase 1 of the Seamless Geology Project, but it is intended that the Seamless Geology dataset will be continually updated and refined as new digital geological mapping data becomes available. Version 2.3 is the 5th major update to the NSW Seamless Geology and was released in May 2023. This release includes: the addition of a "Mafic" attribute field; significant upgrades to the geology of numerous areas in the Lachlan Orogen, Permian-Mesozoic Igneous Province, and Permo-Triassic Basins; and attribute updates and minor error fixes to all layers. NOTE: A substantial amount of overlay, erase and intersect geoprocessing of the original multi-layered Seamless Geology was undertaken to produce the single layer surface NSW Seamless Geology dataset. Due to small tolerance differences between different layers in the Seamless Geology dataset, this has, in some places, created small “sliver” polygons between boundaries common to more than one layer of the original multi-layered NSW Seamless Geology. This is a known issue with the current single layer Seamless Geology dataset and while some attempt has been made to resolve these issues, a number of small “sliver” polygons remain. Users are cautioned to be aware of this problem when using this dataset at high zoom levels (ie. under 1:1,000 scale) and to refer to the full Seamless Geology dataset for clarification.

Map blocks and map units are based on a system originally devised by the British Ordinance Survey. Each 1:1 million scale map sheet is subdivided into 3456 graticular map blocks, each measuring 5’ of latitude by 5’ of longitude. These map blocks are further subdivided into 25 1’ by 1’ map units. A map unit is approximately 3 square kilometres in size.

This layer shows a depth slice from a 3D resistivity model of the crust derived from an inversion of the AusLAMP NSW long period MT data.

The Competitive Allocation Pathway is designed to maximise the value of a suitable unallocated coal resource through a competitive process. The Department of Regional NSW’s (Regional NSW) Guideline for the Competitive Allocation of Coal (December 2020) sets out when the Competitive Allocation Pathway applies.

The NSW Government has clearly identified areas where higher priority land uses mean that coal mining cannot occur. For the State Significant Development application SSD5156 - Rocky Hill area, the prohibition will apply to open cut mining only. Otherwise, within this area coal mining will be prohibited by State Environmental Planning Policy.