Operational Debottlenecking of the Cadia 40-Foot SAG Mill Through Constraint Mapping Analysis

Operational Debottlenecking of the Cadia 40-Foot SAG Mill Through Constraint Mapping Analysis

*C. Geoghegan1 and C. Haines1*C. Geoghegan1 and C. Haines1

Newcrest Mining Limited

Cadia Mine Site, Cadia Road, Orange NSW 2800

(*Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.)

*This paper was presented at SAG Conference held 24-28 September 2023 in Vancouver, Canada. To view the full paper select download file below. 

Abstract: The Concentrator 1 comminution circuit at Newcrest’s Cadia Valley Operation (Cadia) transitioned from atraditional semi-autogenous ball mill crushing flowsheet to a high-pressure grinding roll (HPGR)–semiautogenousgrinding (SAG)–ball mill flowsheet following the Cadia East Expansion Project in 2012. A period ofoperational optimisation followed which by 2018 had successfully shifted the Concentrator 1 circuit throughputconstraint to the 40-foot (ft) 20-megawatt (MW) SAG mill. The SAG mill operated to 97% of installed motorpower, for an annual throughput of 22.5 million tonnes per annum (Mt/a) in the 2019 fiscal year.In 2019 the site metallurgy team endeavoured to operationally de-constrain the SAG mill to lift the nominalprocessing rate of Concentrator 1 with minimal capital expenditure. A theory of constraints methodology wasapplied, utilising robust circuit data from a recent plant survey to campaign improvement projects both upstreamand downstream of the SAG Mill in the crushing and comminution circuits. This paper examines the approachtaken and the initiatives executed, which within a period of 18 months enabled a 400 tonne per hour uplift inthe annualised throughput rate (dt/h). The milling rate improvement was enough to shift the site processingconstraint from the concentrator to the underground mine.

Keywords: Debottlenecking, SAG mill, HPGR, constraints, Cadia