The laboratory used routine industry practices to reduce the field sample masses to a representative smaller aliquot mass that was suitable for a four-acid digestion. Four acid digestion can be considered a complete digestion method for the Callisto sulphide minerals containing nickel and copper. Sample concentrations for a 48-element suite, including nickel and copper, were determined using ICP-OES.

Assays for gold, palladium platinum were digested using fire-assay followed by ICP-MS finish. Assays for rhodium were determined by fire assay with an ICP-OES finish. Galileo provided Cube with wireframe files for the mineralised Callisto lode, geological units, and surfaces for the base of complete oxidation and topography.

Cube used these files to prepare a combined mineralization and geological digital block model which was then used to assign in situ density values, which were the mean of Archimedes Principle DD core measurements available for each rock type. Following exploratory data analysis of the drill hole assays, Cube composited the sample data within the mineralised domain optimised to 1m length. Cube then modelled the spatial continuity of each grade variable using Supervisor software.

Using the interpreted spatial models, Cube then interpolated the 1m composite grades for Au, Cu, Ni, Pd, Pt, Rh and S into the digital block model using Ordinary Kriging (OK) algorithms implemented in Datamine Studio RM software. The block model parent cell size was set to 20m in the east and north orientation which approaches the industry rule of thumb of half the drill spacing which is nominally 50m at Callisto. Sub blocking was allowed to reflect the volumes at wireframe boundaries however estimation occurred at the parent block size using hard boundaries.

Other OK parameters included a minimum of six and a maximum of 16 samples required for each block estimate, a dynamic anisotropic search routine, a three-pass sample search of incrementally expanding search ranges and block discretisation grid of 5x5x2 nodes. Cube validated the OK estimates by visually inspecting drill hole grades and block grades to ensure grade trends in the drilling are reproduced in the block model. Cube also produced global mean comparisons between block grades and declustered composites and swath plots.

These checks were all deemed to be reasonable and accepted by Cube's Senior Resource Geologist. To facilitate the reasonable prospects for eventual economic extraction (RPEEE) of the Callisto MRE, Cube assumed the mining method would be conventional open pit mining using standard diesel-powered equipment, a fly-in fly-out workforce of mining contractors and industry standard assumptions regarding geotechnical pit wall angles and mining costs. Galileo's first pass metallurgical test work indicates that Callisto's mineralisation is amenable to concentration using a conventional crushing, milling, and flotation process.

Cube assumed that all environmental approvals would be granted for mining, processing, and permanent waste storage facilities on the project tenure. Cube assigned resource categories based on overall confidence in the estimate which was guided by drill spacing, OK quality metrics including Kriging Efficiency and Slope of regression, and geological complexity. Indicated resources were assigned to the flatter, shallower western portion of the deposit where drill spacing is generally 50m x 50m and OK metrics show high quality.

Inferred resources have been assigned to the eastern portion of the mineralisation where the sill dips at a steeper angle, drilling intercepts become more oblique, and geological uncertainty increases. A large area of mineralisation to the east and at depth is sparsely drilled and is not classified within any JORC criteria. The RPEEE has been assessed through a pit optimisation analysis and the generation of pit shells using the Lerchs Grossman Algorithm (LGA) within Whittle software.

Galileo provided Cube with the following metal price assumptions based on 12 month calculated averages5 of USD 1,600/oz Pd, USD 975/oz Pt, USD 1,870/oz Au, USD 23,800/t Ni, USD8,420/t Cu, USD 9,420/oz Rh. The optimised pit shell with a revenue factor of 1 reached a depth of approximately 330m from surface down to the 60mRL. This elevation was used as a lower limit of any potential resource likely to be exploited via open pit mining.

The Mineral Resource is reported above 0.5 ppm PdEq above the 60mRL level as this is the approximate marginal economic cut-off grade estimated by the Whittle optimisation analysis.