Name and Location
Ernest Henry underground mine and magnetite processing operation, north-west Queensland, Australia.

Client
Glencore.

Project Description
The project will extend the life of the Ernest Henry Mining (EHM) operations, near Cloncurry, in north-west Queensland, to at least 2024, through the transformation of openpit mining operations into a major underground mine, together with the construction of an associated magnetite extraction plant.

The decision follows feasibility studies into the construction of a magnetite processing facility and the installation of full-scale underground mining operations at EHM that have resulted in a revised ore reserve estimate of 72-million tonnes, at a grade of 1% copper, 0.5 g/t gold and 22% magnetite.
The total tonnage represents a 600% increase over previously published underground reserves.

Ore will be mined principally from a major hoisting shaft to be sunk to a depth of 1 000 m, producing six-million tonnes a year of ore at full capacity.

The project will enable EHM to achieve yearly production levels of about 50 000 t of copper and 70 000 oz of gold in concentrates from 2013, when processing from openpit mining operations ceases.

Copper/gold concentrates from EHM will continue to be hauled by purpose-built trucks to Xstrata’s Mount Isa copper smelter, with the anode then railed to Xstrata Copper’s refinery, in Townsville.

The existing concentrator at the EHM will be reconfigured to align with the underground mine production rate, resulting in continuous milling at lower throughput levels to deliver improved metallurgical recoveries and energy efficiencies.

A separate extraction circuit will be installed to produce the magnetite concentrates.
The magnetite processing operation at EHM will produce about 1.2-million tonnes of magnetite a year for export to Asia, making it Queensland’s first iron-ore producer.

Value
The project is estimated at A$589-million.

Duration
Construction of the magnetite plant was completed at the beginning of 2011.

First production began in late 2011.

Latest Developments
Glencore’s transition of the Ernest Henry mine from an open pit to an underground  operation  has celebrated a significant milestone; starting operations from a new one kilometre-deep hoisting shaft.

The operation  will  now begin to ramp up copper production from three-million tonnes  to  six-million tonnes a year in 2015 and similarly double yearly metal  production  to  50 000 t of copper and 70 000 oz of gold in concentrate over an extended mine life to 2026.

“This investment in Ernest Henry has effectively added 14 years to the life of the  mine  to  2026,” says COO for  copper assets  in  North  Queensland, Mike Westerman.

The underground project started in December 2009 and has involved:
• more  than  50 km of underground development accessed by a 6 km decline;
• the construction of associated  infrastructure,  including the underground primary crusher  and  1.2  km  of below surface and overland conveyors to transport ore to and from the hoisting system;
• the installation a 75-m-high permanent headframe to house the hoisting  system and with a capacity to lift about 1 000 t/h; and
• the reconfiguration of the  concentrator  to  align  with  the underground production rate.

Four production levels are operational using an innovative sublevel caving mining method  and  have  trucked ore to the surface through the decline since December 2011 while the project was under way.

As at December 2013, Ernest Henry had total ore reserves underground of 74-million tonnes at 1.04% copper and 0.53 g/t gold.

Key Contracts and Suppliers
None stated.

On Budget and on Time?
The project was initially estimated to cost A$542-million, but the cost was revised to A$589-million.

Contact Details for Project Information
Glencore, Vicki Wilson, tel +61 7 4769 4578 or email Vicki.wilson@glencore.com.au.