The CMGP is located in the Archaean Murchison Province, a granite-greenstone terrane in the northwest of the Yilgarn Craton. The three goldfields of Big Bell, Cuddingwarra and Day Dawn are made up of greenstone belts trending northnortheast are separated by granite-gneiss domes, with smaller granite plutons also present within or on the margins of the belts. The greenstone belts comprise tholeiitic and high-Mg basalts, komatiites and other ultramafic volcanics, mafic and ultramafic intrusives (dolerites, gabbros, dunites), felsic and intermediate volcanics and meta-sediments including banded iron formations.

Both Golden Crown and Great Fingall ore bodies are moderately dipping quartz veins with ore widths for Golden Crown of approximately 3m true width and 4.5m true width for Great Fingall.

The Big Bell deposit is located within a greenstone and sedimentary sequence within the Murchison Province of the Archaean Yilgarn cratonic block. The lithological contacts adjacent to the orebody generally strike at around 30° from magnetic north and dip 72° to the east. The orebody dip varies locally from 55° to 80°. Mineralisation is hosted within potassium feldspar-schist (KPSH), altered schist (ALSH) and biotite schist (BISH). Footwall excavations are located in amphibolite schist (AMPH), a basalt equivalent.

A graphitic shear structure is located in the footwall of the orebody, varying in thickness from 2cm to 45cm and located from 5m to 20m in the footwall of the orebody. A cordierite schist (CRSH) is the footwall marker unit to the deposit.

The Big Bell lode system (KPSH, ALSH, BISH) has been defined along strike for over 1,000m and to a depth of 1,430m. In plan view the lode system is lenticular in shape varying from five to eight meters in width at the extremities and up to fifty meters in the central area of the deposit.

The CMGP open pit program consists of conventional open pit methods, conventional mining equipment with selective grade control methods. The progressive extraction plan considers the Big Bell South, Shocker-1600 and Fender pits in the Big Bell project area, and the Yellow Taxi, South Fingall and Great Fingall pits in the Day Dawn area. Whittle Four-X optimisation software was used for the pit optimisation work. The pit optimisation work excluded inferred resources and all scheduling and productivity estimates were based on final and geotechnically cognisant mine designs.

Rib pillars and crown pillars are left for all stopes in order to avoid the need for backfill to all stope voids.

A longitudinal sub-level caving (SLC) method is used at Big Bell, using a top-down approach. The wider, central 350m section is mined from a central slot in the orebody out.

The sub-level interval is 25m and the orebody width varies from 10m to 40m, with twin ore drives developed in the central section where the orebody widths exceed 22m.

The CMGP open pit program consists of conventional open pit methods, conventional mining equipment with selective grade control methods. The progressive extraction plan considers the Big Bell South, Shocker-1600 and Fender pits in the Big Bell project area, and the Yellow Taxi, South Fingall and Great Fingall pits in the Day Dawn area. Whittle Four-X optimisation software was used for the pit optimisation work. The pit optimisation work excluded inferred resources and all scheduling and productivity estimates were based on final and geotechnically cognisant mine designs.

This area is centred upon the Tuckabianna processing hub which is a 1.2 - 1.4 million tonne per annum CIP plant and associated infrastructure. The southern part of the overall CMGP makes up the CGO covering the historic gold mining centres of Big Bell, Cuddingwarra, Day Dawn, Pinnacles (Comet), and Tuckabianna.

The Tuckabianna Plant was refurbished and commissioned during the year to reach commercial production on 1 April 2018. In its first quarter of production (Q4 2017/18) gold output was 8,917 ounces at a C1 Cash Cost of A$1,363 per ounce and an all-in sustaining cost of A$1,550 per ounce. (http://www.minesandprojects.com/reports/annual/Westgold_Annual_Report_2018.pdf - pg 18)

The processing circuit is a simple CIL scenario and consists of:
• Delivery of ore to a Run-of-Mine (ROM) pad for direct tip to a primary crusher;
• Single stage jaw crushing of ROM ore;
• Two stage grinding via a primary SAG (semi autogenous grinding) mill and ball mill to P80 75 µm;
• Scrubbing and pre-leach thickening of historic tails;
• Carbon in Leach and Adsorption;
• Elution of Gold;
• Production of Gold Dore.