Underground Ventilation Power Savings

Gold Fields Granny Smith Mine.

Introduction

Gold Fields Australia is part of the global Gold Fields group, a globally diversified gold producer with nine operating mines in Australia (including the Gruyere JV), Peru, South Africa and West Africa (including the Asanko JV), and a joint venture project in Canada and another in Chile.

Our four Australian mines – Agnew, St Ives, Granny Smith and Gruyere– are located in the Goldfields region of Western Australia where nearly 4,000 people are employed on a residential and fly-in, fly-out basis.

To reduce underground secondary fan power consumption, Gold Fields Australia decided to trial a 260kW 1000V VVVF Drive Fan Starter with a twin stage 110kW fan. The 6-month trial was implemented at Gold Fields Granny Smith mine located in Western Australia, operating on an isolated power system, to gather sufficient data to evaluate potential realised savings, with a view to return or purchase the 260kW 1000V VVVF Drive Fan Starter.

SMEC Power & Technology supplied and commissioned on site, a 260kW 1000V VVVF Magnetek GP1000-E Drive in a custom-built enclosure, complete with on board PLC remote accessibility and an independent PC to remotely access the Magnetek’s VVVF Drive G7 control board which allowed for drive parameter monitoring and changes to be carried out remotely.

The TLT Turbo Air twin 110kW fan and 1000V VVVF Drive were installed on both development declines and inclines during mid-summer when intake temperatures were at their highest during the year.

The 260kW 1000V VVVF Fan Starter is a standalone enclosure design – utilising a closed loop liquid cooling system, negating the requirement for expensive dedicated air-conditioned container rooms.

Outcome

Over the six-month trial the realised power saving averaged at 30 % with individual months achieving powers savings around 50 %. The realised savings exceeded Gold Fields expectations and the decision was made to purchase the 1000V VVVF Drive, at an agreed cost, and to place future orders for the Magnetek GP1000-E VVVF Drive, to allow Gold Fields to enjoy ongoing increased power savings.

Custom Built, standalone, Enclosure designed for harsh underground applications.

Magnetek 260kW GP1000-E 1000V VVVF Drive, being tested and commissioned prior to delivery to Gold Fields Australia.

1000V VVVF Drive enclosure c/w with an Inline Reactor, Tuned harmonic filter and DC Bus choke as standard features.

Component cooling is via a closed loop, maintenance free, liquid to air cooling system.