The Nolans Bore deposit is located at the southern end of the Reynolds Range in the central Aileron Province of the Arunta Region. The Aileron Province comprises greenschist to granulite facies metamorphic rocks with protolith ages in the range 1865-1710 Ma.

Supracrustal rocks in the Reynolds Range are divided into two broad units: the Lander Rock Beds (LRB) and the Reynolds Range Group. The LRB comprise (meta)turbiditic rocks that range in metamorphic grade from greenschist to granulite. In the Nolans region, the LRB include schist, phyllite, andalusite hornfels, garnet-cordierite-biotite-quartz granofels, sillimanite-biotite-cordierite-orthoclase granofels, tourmaline metaquartzite, and tourmaline-quartz pods.

Granite intrusion occurred in the Reynolds Range area between 1810 and 1790 Ma. Granitic rocks which intrude the LRB in the vicinity of Nolans are a southern extension of the Mount Boothby Orthogneiss (MBO). The supracrustal rocks and granites were overprinted by high grade metamorphism to amphibolite and granulite facies during 1590-1560 Ma.

Nolans Bore is a geologically unique deposit, which has world-class characteristics in size and grade of rare earth elements (REE), phosphate, uranium and thorium.

Apatite-hosted REE-P-U(-Th-F) mineralisation at Nolans Bore is distributed over an area of approximately 150 hectares within a kilometre radius of the bore. Primary mineralisation occurs predominantly in a series of sub-parallel tabular zones of massive fluorapatite (Ca₅(PO₄)₃(F,OH)), or as a stockwork of fluorapatite ± allanite ± carbonate veins and associated calcsilicate alteration. The massive zones dip steeply (65°-90°) to the NNW, are up to about 75 metres thick, and extend laterally and at depth over tens to several hundreds of metres. They are hosted primarily by gneissic granite assigned to the MBO, and also by the LRB and pegmatites.

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Consistently higher grades and greatest widths of mineralisation are observed in the North Zone Resource of the deposit. However, drilling during early-2008 intersected a new zone of high-grade mineralisation in the Central Zone, under several metres of alluvium.

A simplistic three-fold subdivision of rock types is apparent in the North Zone at Nolans Bore:

• A footwall granitic gneiss (to the SE), which includes mineralised stockwork of fluorapatite + calcsilicate alteration zones (see bottom half of photo below);
• A main mineralised zone, comprising massive zones of fluorapatite, truncated by a localised mylonite/breccia zone (see top half of photo below); and
• A hangingwall gneiss (to the NW), which hosts fluorapatite zones.

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The bulk (65-70%) of the REE-U content in the fluorapatite rock is hosted by minor amounts (up to 7-8%) of minute monazite-group (“cheralite” - [LREE, Ca][P, Si]O₄) and other REE-rich mineral inclusions. Only about 30-35% of the REE-U is hosted in the crystal lattice of the fluorapatite. The image below is a Scanning Electron Microscope (SEM) photograph showing crackle/mosaic brecciation of fluorapatite with cheralite infill. Other identified REE-U-Th mineral species include bastnaesite and thorite.

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