Gold mineralization in the Nicolson’s Find area is structurally controlled within the 400 m wide NNE trending dextral strike slip Nicolson’s Find Shear Zone (NFSZ) and is hosted within folded and metamorphosed turbiditic greywackes, felsic volcaniclastics, mafic volcanics and laminated siltstones and mudstones. This zone forms part of a regional NE-trending strike slip fault system developed across the Halls Creek Orogen (HCO).

The NFSZ comprises a NNE-trending anastomosing system of brittle-ductile shears, characterised by a predominantly dextral sense of movement. The principal shear structures trend NNE to N-S and are linked by NW, and to a lesser extent, by NE shears. Individual shears extend up to 500m along strike and overprint the earlier folding and penetrative cleavage of the HCO.

The overall geometry of the system is characterized by right step-overs and bends/jogs in the shear traces, reflecting refraction of the shears about the granite contact. Within this system, the NW- striking shears are interpreted as compressional structures and the NE striking shears formed within extensional windows. Mineralization is primarily focussed along NNE trending anastomosing systems of NNE-SSW, NW-SE and NE-SW oriented shears and splays. The NNE shears dip moderately to the east, while the NW set dips moderately to steeply to the NE. Both sets display variations in dip, with flattening and steepening which result in a complex pattern of shear intersections.

Mineralisation is strongly correlated with discontinuous quartz veining and with Fe-Si-K alteration halos developed in the wall rocks to the veins. The NE shears are associated with broad zones of silicification and thicker quartz veining (typically white, massive quartz with less fracturing and brecciation); however, these are typically poorly mineralized. The NW-trending shears are mineralized, with the lodes most likely related to high fluid pressures with over-pressuring and failure leading to vein formation. Although the NE structures formed within the same shear system, the quartz veining is of a different generation to the mineralized veins.

Individual shears within the system display an increase in strain towards their centres and comprise an anastomosing shear fabric reminiscent of the pattern on a larger scale.

Mining continued at both Nicolsons and Wagtail underground mines during the period. There was no open pit mining undertaken.

Nicolsons Underground Mine
Nicolsons underground mine is located adjacent to the Nicolsons processing plant and has continued to be the cornerstone of production at the operation. Development has progressed to approximately 380 metres below surface at the time of reporting.

At Nicolsons Mine, the primary ore zones in the high-grade Johnston Lode were mined out in the first half of the year, with remnant mining continuing in other areas of the mine. Mining of remnant ore is expected to be completed during the 2023 financial year.

Wagtail Underground Mine
Wagtail is located adjacent to the Nicolsons Underground Mine. Pantoro commenced mining Wagtail (and the nearby Rowdies mine) as open pit operations in October 2016.

At Wagtail, operations have continued to be advanced in the Rowdies Lodes which include the high grade REV and Wagon structures discovered during the previous year. In addition, development has now reached the Wagtail South orebody, adding a major work area for the coming year. The additional ore available from the Wagtail South orebody provides a platform for the mine to continue to produce at similar levels to those achieved during the past several years.

The Wagtail South surface ventilation raise bore was completed in early July 2022, after a protracted delay in mobilization of the raisebore rig due to difficulties at the previous worksite which was unrelated to Pantoro. The raise was planned to be completed in February 2022, and the delay contributed to reduced work areas during the period.

Development is now underway in Wagtail South, and initial ore development grades have exceeded expectations. Wagtail South will have a key development focus throughout the coming year. The Rowdies orebody continues to deliver high grades at depth. Development has now reached the 1950 mRl, approximately 350 metres below surface.

The Halls Creek Project was developed by Pantoro during 2015, with the first gold pour completed during the same year. The project includes underground and open pit mining, and a modern CIP processing facility.

In June 2018 Pantoro commissioned a Steinert ore sorter and new processing circuit at Nicolsons. The ore sorter has been operating effectively enabling the upgrade of low grade stockpiles and medium grade ore from mining operations. Full time operation is expected as ore feed from Wagtail and Nicolsons ramps up.