On 29 June 2023, Catalyst Metals acquired 100% of the ordinary shares of Superior Gold Inc., a Canadian-based gold producer that owns 100% of the Plutonic Gold Operations located in Western Australia, through its wholly-owned subsidiary Billabong Gold Pty Ltd.
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Summary:
Mineralization
At Hermes the Hawkeye, Trapper, Klinger, Winchester & Blake deposits are sub-parallel, northeast trending, mineralised zones. Mineralisation at all deposits is typically associated with quartz veins at or near the sheared contact of mafic amphibolite footwall and hangingwall quartz-biotite-sericite schists. Graphitic schist occurs to a minor extent on the hangingwall and footwall sides of the mineralisation at Trapper, Klinger and Blake. The base of strong oxidation varies from 20-30 m vertically below surface at Hawkeye & Winchester, and from 25-45 m at Trapper, Klinger & Blake. Transition to fresh rock occurs at approximately 30-50 m and 40-65 m, respectively.
In general, the mineralised quartz veins, foliation and relict bedding are steeply NW-dipping to sub-vertical in both the Hawkeye and Trapper deposits and high-grade shoots are interpreted to plunge shallowly to the north within the mineralised plane.
Hermes South
Gold mineralisation occurs within a predominantly metasedimentary sequence of the Proterozoic Peak Hill Schist and mafic units. The Peak Hill Schist comprises quartz-sericite schist and quartz-muscovite schist and is located on the south-western extreme of the Marymia Inlier.
Deposit Type
In the Hermes Gold Mine and BBJV Projects there are two broad mineralisation styles (Outhwaite, 2013) referred to here as the Peak Hill Type and the Bryah Type.
The Peak Hill Type gold deposits are hosted in rocks that are generally highly deformed (four or more fold events) and metamorphosed (up to amphibolite facies), generally represented by the Peak Hill Schist Formation. Mineralisation is early in the paragenesis, (syn- to post-D1 isoclinal folding) with folded mineralisation commonly observed. Previously mined examples include Peak Hill Main/Five-Ways, Mt Pleasant, Jubilee, Wilgeena and St Crispin. The Hermes deposits may be examples of mineralisation that belongs in this category.
The local controls on this deposit class are difficult to identify, because of the effects of strong, postmineralisation deformation, and probable remobilisation of Au. Despite this problem, some similarities between the deposits have been recognised:
• Located on a major structural and metamorphic gradient. The Peak Hill camp, Hermes, Wilgeena and Central Bore all lie around a significant gradient from high-strain, highly metamorphosed rocks at the core of uplifted basement blocks, outwards to lower-strain, less metamorphosed rocks. This gradient is a transitional structural zone up to a few kilometres wide. This zone was probably a major fluid conduit during early deformation, and hence a first-order corridor for Au exploration;
• Located at or around mafic-sedimentary contacts. With the exception of Central Bore, which is on a granite-sedimentary contact, all of the mentioned Peak Hill-style occurrences are closely associated with mafic rocks within dominantly sedimentary sequences. The mafic rocks are typically amphibolite, after dolerite or basalt, but high-Mg to ultramafic rocks are noted at Hermes, Hermes South, and possibly the Peak Hill camp (high Cr and Mg);
• Early structures. A likely early age on the controlling structural corridor has been recognised, based on the repetition of stratigraphy, which was then folded together during the identifiable fold events. The identification of early, controlling structures has proven difficult, due to the overprint of subsequent deformation events;
• Strong plunge controls. Due to the multiple folding events these deposits have strong plunge controls, meaning they can have small surface footprints – especially when considering their general lack of pathfinder anomalism (see below). Exploration must take this fact into account;
• Limited geochemical signature. Wilgeena, Central Bore, St Crispin, Pelorus and possibly Peak Hill have a limited range of pathfinder elements associated with the Au mineralisation – scattered W, Bi, Pb and Zn, but very little else. Hermes is a clear exception however, as limited multi-element analysis has shown that this system has a strongly developed pathfinder association, similar to that found in typical Archean Au systems: As, Sb, Mo, W, Bi, etc.
Summary:
Crushing
Run of Mine (ROM) ore is trucked to the ROM pad from the underground mine. The ore is classified and stockpiled according to gold grade, arsenopyrite content, pyrrhotite content, and graphitic content so that blending can be undertaken to maintain an optimal feed to the processing plant. Oversize ore and tramp metal are sorted from stockpiles and broken on the ROM pad using a loader or excavator. Any oversize that cannot pass through the primary crusher grizzly is broken by a rock breaker mounted at the grizzly.
The PP1 crushing circuit has a nameplate capacity of 2.5 Mtpa and consists of three stages of crushing:
A 60 x 48 Jacques primary double-toggle jaw crusher,
A Symons 7’ SXHD secondary standard head cone crusher, and
Two Symons 7’ SXHD tertiary short-head cone crushers.
In addition, there are separate surge bins that are operated in closed circuit with two Nordberg 7.1 m x 2.4 m double deck vibrating banana screens. Crushed ore exits the pro duct screen with a top size of 10 mm and is stored in the fine ore bin. The fine ore bin has a live capacity of 3,000t.
PP1 crushing circuit contains 2 x Thermo Scientific Ramsey 10-17 belt scales (CV07 and CV13) for measuring mass of circuit ore.
The now decommissioned PP2 oxide crushing circuit consists of a 48 x 42 Kemco double toggle jaw crusher with a nameplate capacity of 1.2 Mtpa, a product conveyor and a coarse ore stockpile with a live capacity of 2,200 tonnes. Crushed oxide ore was transferred to PP2 grinding mills using two variable speed belt feeders.
Grinding
Crushed ore is withdrawn from the Fine Ore Bin via two belt feeders (CV 14/15), which transfer ore onto the mill feed conveyor (CV04) that feeds into the primary grinding mill (ML01). Mill feed can also be fed via an emergency feed hopper (CV02) which is fed via the oxide coarse ore feed slots. Quicklime is discharged onto CV04 via a variable speed, manually controlled rotary valve from a 200t lime silo. Liquid lead nitrate (40% w/w) is discharged directly into CV04 head chute into the grinding circuit.
The grinding circuit comprises a Svenson 4.5m diameter by 5.63m long primary mill and two Svenson 4.2m diameter by 5.63m long secondary ball mills. The primary mill has a grate discharge and is rubber lined. Its speed is fixed at 14.6 rev/min (72 per cent of critical) and the installed power is 1,600kW (1,350kW drawn). 78mm diameter forged steel grinding media is used in the primary mill.
The secondary mills are rubber lined overflow mills run at 15.8 rev/min (75% of critical), also with 1,600 kW power (1,450 kW drawn). The grinding circuit throughput is currently operated at 165 tph with a primary mill and one ball mill configuration; this however can be increased to 230 tph by running the stand-by ball mill. 40 mm High Chromium steel grinding media is used in the secondary mills.
The primary mill discharge slurry is screened on a 6 mm aperture scalping screen and oversize is returned to the primary mill. Screen undersize reports to the ball mill discharge hopper. ML01 mill undersize and ML02/ML03 mill discharge is pumped to a hydrocyclone cluster consisting of 18 x 250 mm Cavex cyclones. Operating pressure is 130 to 150 kPa. Each cyclone contains 90 mm ceramic vortex finders and 75 mm ceramic spigots. Coarser cyclone underflow is returned to the operating secondary ball mill for further size reduction. Cyclone overflow (approximately 80% passing 75µm) discharges over a trash screen (1mm) with screen undersize reporting to the leaching circuit.