Summary

Deposit type

• Vein / narrow vein
• Breccia pipe / Stockwork
• Porphyry
• Intrusion related

Summary:

to develop the known reserve.

The deposit style is still somewhat controversial. Features consistent with porphyry-style mineralization, classic orogenic shear zones, and intrusion-related gold–copper–bismuth mineralization, are all recognized, giving rise to a variety of genetic interpretations.

Boddington does not fit any classic Archean orogenic gold deposit model, having a general lack of quartz veins and iron carbonate alteration, a copper ± molybdenum ± bismuth association, zoned geochemical anomalism, and evidence of high-temperature, saline, ore-forming fluids. Detailed petrographic, geochemical and melt inclusion studies suggest a late stage ~2,612 Ma, monzogranite intrusion as one of the principal sources of the mineralizing fluids. However, there is also local evidence for older, perhaps proto-ore, porphyry-style copper ± gold in the dioritic intrusions and patchy, locally high-grade, orogenic-style gold mineralization associated with enclosing shear zones and brittle

Mining

• Truck & Shovel / Loader

Summary:

quipment is owner-operated and includes a large mining truck fleet (240-tonne class), electric rope shovels, support equipment, and drills. Mining is done predominantly on 12 m benches.

Overall pit slope angles varied between approximately 37–52º according to geology and location of pit infrastructure such as ramps and haul roads. Inter-ramp slope angles in hard rock varied between 58–60.8º depending on specific conditions encountered within pit walls. The inter-ramp slope angles within oxide slopes varied between 20–30º.

All drilling operations are performed by Newmont with Newmont owned rigs.

Vertical production holes are drilled vertical (229 mm diameter) with a nominal bench height of 12 m, with 1.5 m subdrill for a 13.5 m overall hole length. Wall control holes are 127 mm diameter for batters and buffers and 115 mm diameter for pre-split. A variety of angles and lengths are used to suit various geotechnical based ground control domains. All rigs are GPS controlled for hole positioning and on-board telemetry systems for recording depth, angle, drill time etc.

Production blasting utilises augered and pumped Heavy ANFO blends, with a nominal approximately 500 kg per hole. Crushed aggregate, produced on site, is used as stemming for the top 3.7 m of each hole. Electronic detonators are used for ore blasts whereas nonel detonators are used on waste blasts. Nominal Powder Factors on production blasts vary from 1.18 to 1.40 kg/m3.

The wall control configuration features a triple bench design; a 70° or 75° angled batter on the top bench is followed by a single pass 24 m vertical pre-split for the second and third benches. All first bench blasts are fully free faced.

In 2021, was delivered the gold industry’s first Autonomous Haulage System (AHS) fleet at the Boddington operation in Australia. The fully autonomous fleet of 36 trucks has improved mine safety and productivity while extending mine life.

Comminution

Crushers and Mills

Summary:

ball mills, and hydrocyclone classification to generate a milled product with a P80 of 150 micrometers (µm) at a slurry density of around 35% solids.

Coarse Crushing (in mining area)
The mine haul trucks dump ore to two primary crushers (60/113 MK-II gyratory crusher). Crushed ore is transferred via an overland conveyor to a 230,000 t capacity (40,000 t live capacity) stockpile adjacent to the processing plant. Dozers operating on the coarse ore stockpile can increase the total storage capacity up to 400,000 t.

Fine Crushing and Screening (process plant)
Three apron feeders reclaim ore from beneath the coarse ore stockpile and delivers the ore to the secondary crusher feed conveyor and the six secondary crushers (MP1000 cone crusher, five original with a sixth crusher installed in late 2010), which are operated in closed circuit with four coarse screens (three original with a fourth coarse screen installed in 2010).

Oversize material returns to secondary crushing and the fine material reports to the tertiary crushing plant that consists of four HPGRs. The tertiary product is stored in a 20,000 t fine ore bin ahead of the ball milling circuit. Fine ore is reclaimed from the bin via eight reclaim belt feeders (two per four parallel milling trains) and delivered to the fine screens ahead of ball milling. Each line consists of two screening units.

Undersize material from the screens reports to one of four cyclone feed hoppers and the oversize returns to the HPGRs for additional crushing. Cyclone clusters classify the finely-crushed particles, with the finer cyclone overflow material (80% passing 150 µm) reporting to the flotation distribution box and the coarse cyclone underflow material to a split between the ball mills or flash flotation cell (for free gold recovery).

Tails from the flash flotation cells are recycled back to the ball mills for further grinding. The target final product grind size from the milling circuit is 80% passing 150 µm, although increased throughput rates in 2011 and 2012 resulted in grind size P80 coarsening to 170 to 190 µm at times. Improved process control and increased ball mill operating power draws have reduced the grind size back to around 150 to 160 µm at the elevated throughput rates.

The regrind plant consists of two Verti-mills (one duty and one standby) with product reporting, via cyclone clusters, to the cleaner flotation plant. The cleaner flotation facility has three sequential stages with final

Beneficiation

• Smelting
• Dry Screening
• Crush & Screen plant
• Flotation
• Agitated tank (VAT) leaching
• Carbon in leach (CIL)
• AARL elution
• Carbon adsorption-desorption-recovery (ADR)
• Dewatering
• Filter press
• Solvent Extraction & Electrowinning
• Cyanide (reagent)

Summary:

it and carbon in-leach circuit. The flotation circuit process recovers gold-copper concentrate before the material is then processed by a traditional carbon-in-leach circuit where the remaining gold is recovered to produce doré.

The processing plant has a nominal capacity to process approximately 40 million tonnes of ore per year with optimization projects underway to further increase this capacity.

The cyclone overflow from the mill circuit is treated in a flotation circuit that produces a copper–gold concentrate for export. Rougher and scavenger flotation concentrates are reground and cleaned to achieve an acceptable final concentrate grade. The concentrate is thickened and filtered before being trucked to port.

Cyclone overflow from the mill circuit is treated in a flotation circuit that produces a copper– gold concentrate for export. Rougher and scavenger flotation concentrates are reground and cleaned to achieve an acceptable final concentrate grade. Concentrate is thickened and filtered before being trucked to the port of Bunbury.

The cleaner scavenger tailings stream is thickened and leached under elevated cyanide levels. Scavenger tailings are thickened and leached in a conventional leach/adsorption circuit. Leached slurry from the cleaner scavenger tailings leach circuit is delivered to the scavenger tailings circuit for combined recovery of gold.

Leach residue is pumped to the residue disposal area, and residual CNwad is maintained below a targeted level by a Caro’s acid cyanide destruction plant. This facility can treat the following streams:
• Decant water returning to the plant so that cyanide levels do not inhibit flotation;
• Decant water recycling to the decant pond to maintain CNwad levels in the pond at an average of 30 ppm and a not-to-exceed level of 50 ppm;
• Residue slurry from the plant to protect the decant pond from excursions caused by shortterm variability in the copper head grade.

The carbon from the scavenger tailings adsorption circuit is treated by conventional split Anglo American Research Laboratory (AARL) method elution and reactivated in horizontal reactivation kilns. Gold recovery from the eluate is by electrowinning, cathode sludge filtration and drying, and smelting.

There is a flash flotation and gravity circuit installed in the process plant. These circuits have not been operated and remain decommissioned.

Gold and Copper Recovery to Concentrate
The flotation distribution box transfers cyclone overflow product from each of the four parallel grinding lines in to three parallel trains comprising, eight-unit flotation cells. Concentrates produced by cells #1 and #2 report to the coarse cleaner cells for final cleaning, and product from the other cells reports to regrind thickening.

The regrind plant consists of two Verti-mills (one duty and one standby) with product reporting, via cyclone clusters, to the cleaner flotation plant. The cleaner flotation facility has three seque

Water Supply

Summary:

River under a license from the Department of Water or from regional water bores which are available all year round. Process water is also sourced as reclamation of water from the decant pond at the TSF.

Potable water for the camp and mining operation is sourced from two 550 kL water storage tanks.

The site-wide water balance is managed through a GoldSim model, with regular water use, abstraction and storage capacity data regularly fed into the model to obtain reliable forecasts of process and raw water.

Commodity Production

Operational metrics

Personnel

Job Title	Name	Profile	Ref. Date
Environmental Superintendent	Tessa Purcell		Apr 10, 2024
General Manager	Chris Dark		Apr 10, 2024
Managing Director	Mia Gous		Apr 10, 2024