St Ives lies within the Kambalda domain, a subset of the Norseman-Wiluna Belt. The Kambalda domain is bound by the north-northwest trending Boulder-Lefroy fault (BLF) and Zuleika shear. The region has undergone four compressional events predated by early extension, and has been metamorphosed to upper greenschist or lower amphibolite facies.

The main structural feature of the St Ives area is the gently south-plunging Kambalda anticline, which extends 35km from the south end of the Kambalda dome to the Junction mine. The majority of known gold deposits are proximal to the trace of the anticlinal axis. A major second order structure known as the Playa shear splays off the BLF shear zone and can be traced through the St Ives field for a distance in excess of 10km.

There are several styles of gold mineralisation at St Ives. Individual deposits may contain more than one of these styles:

• Lode mineralisation: Archaean lode mineralisation typically consisting of 0.5m to 20m wide mesothermal vein complexes that may also have hydraulic breccias and/or mylonites. Mineralisation is typically discontinuous with short range predictability
• Supergene mineralisation: Broad zones of flat-lying gold mineralisation in weathered Archaean and overlying tertiary sediments
• Palaeoplacer mineralisation: Placer deposits hosted by palaeochannels in the unconsolidated tertiary sediments that overlie the Archaean basement.

St Ives currently operates three underground mines and one open pit. The underground is accessed via a decline. Mining contractors deploy long-hole stoping and paste/rock fill. Current underground mines are relatively shallow and are configured to mitigate geotechnical seismic risk through mine design, scheduling and defined ground support regimes.

Open pits are mined using conventional drill and blast with truck and shovel. Surface mining operations are carried out using contract mining.

Ore from both open pit and underground operations is transported with road trains from individual
mining operations to the central St Ives processing RoM pad.

St Ives operates a 4.7Mtpa processing plant that consists of primary crushing, SAG/Ball milling, gravity and CIP circuits.

The Lefroy Mill was commissioned in December 2004 and achieved design capacity within seven months. It treats medium- to high-grade ore through a 4.8 Mtpa variablespeed dual-direction 13.5 MW sag mill with wrap-around motor. Oversize from the mill (scats) is in closed circuit with a 140-tonne-per-hour pebble crusher. A gravity circuit recovers the gravity-recoverable gold from the milling circuit and the concentrate is treated separately through to bullion form. The mill cyclone overflow product flows to a five-stage leach circuit consisting of mechanical agitators, reagent addition and oxygen sparging.

Leached slurry passes through the six-stage carousel pump cell adsorption plant and subsequent five-tonne-capacity acid wash, elution and electrowinning circuits which produce calcine ready for smelting. Bullion is shipped to the refinery. Tailings are alternately deposited on two paddock-type tailings facilities which are constructed upstream.