Mineralisation is associated with quartz veining and alteration focused within sub volcanic basaltic-andesite sills and adjacent volcaniclastic sediments. The deposits appear to have formed as the result of a rheological contrast between the porphyritic sub-volcanic sills and the surrounding volcaniclastic sediments, with the sills showing brittle fracture and the sediments ductile deformation, and have many similarities to well documented orogenic -lodestyle gold deposits.

Mineralisation at Wyoming One is developed within a number of different zones:

- porphyry – mineralisation hosted by a quartz stockwork within the carapace of a subvolcanic sill with dimensions roughly 60m x 150m. High grade mineralisation is developed along the eastern contact of the zone (‘contact’ zone);

- hangingwall – a linear zone of mineralisation situated approximately 30m to hangingwall of the ‘porphyry’ mineralisation and hosted within silicified and brecciated carbonaceous mudstone. This zone is interpreted to fold around the northern end of the porphyry (northern zone);

- ‘376’ – east west zone of high grade mineralisation developed at the northern contact of the porphyry. Interpreted to be a bounding structure and primary fluid conduit. Other high grade east-west structures e.g. ‘831’ appear to be developed en-echelon and to the south of the ‘376’ zone;

- footwall – a low grade zone located in a similar stratigraphic position to the hangingwall zone but footwall to the porphyry.

Mineralisation at Caloma Two is developed within a series of ‘quartz lodes’ which dip north at flat to moderate angles and hosted dominantly within the sub-volcanic sills. Mineralisation is also developed along a sediment contact zone which appears to be a potential linking structure with the Caloma mineralisation to the north. There is also evidence for the development of an inverted saddle reef at depth. The lodes are cross cut by a number of post mineralisation dolerite dykes.

Open cut mining at TGO commenced in 2014, based on four gold deposits: Wyoming One, Wyoming Three, Caloma One and Caloma Two.

Following the completion of the Wyoming Three and Caloma One open cuts in 2015 and 2017 respectively, mining in the Wyoming One and Caloma Two open cuts ceased in the 2019 financial year. An underground mine is under development at the Wyoming One deposit, with stope ore extraction anticipated later in 2019.

Alkane is also undertaking major gold exploration activities in the gold corridor between Tomingley and Peak Hill as part of a project to identify additional resources for processing at TGO.

The operation continued to perform very well as open cut mining wound to a close: mining in the Wyoming One open cut finished in December 2018 and in Caloma Two in January 2019. Medium and low-grade ore stockpiles were then processed for the balance of the financial year, enabling gold production to continue at the design feed rate of 1Mtpa. Once processing of low-grade stockpiles is finished, gold production will revert to underground ore, most likely in early 2020.

Alkane’s Board approved the development of underground operations in September 2018. These works commenced in January 2019 and continue on schedule and on budget. The main portal is located at the base of the Wyoming One open cut, with the decline spiralling down outside the ore zone past several ore levels. Production of ore from the first underground stope is scheduled before the end of calendar year 2019. TGO has recruited a team of experienced personnel in preparation for underground ore production. The original mine plan is to extract 1.24Mt of ore with grading 2.7g/t gold, for a resultant 108,000 ounces of gold.

The Tomingley Gold Operations processing plant utilises two stage crushing, single stage grinding and a gravity/CIL gold recovery circuit. The plant has a designated throughput of 1.25mtpa of oxide ore and 1.0mtpa of fresh (sulphide) ore. The plant has been operational since February 2014.