Case study – ventilation planning for Bog Zone,

Lisheen MineKristen Hopperstead

Introduction

Ventilation in mine Ventilation in mine design processdesign processo FeasibilityFeasibilityo Design changesDesign changeso Quantify amount of air Quantify amount of air

requiredrequired Impact of larger mobile Impact of larger mobile

equipment fleetequipment fleeto Auxiliary circuitAuxiliary circuito Main ventilation circuitMain ventilation circuit

Secondary EgressSecondary Egresso Impacts shaft Impacts shaft

design design Implementation Implementation

o staged staged implementationimplementation

ConclusionsConclusions

Location

Lisheen’s Vital Statistics

Cool, wet climate 352 Employees from

14 countries Underground Zinc

and Lead Mine High grade Mine life 1999 - 2014 1.6 million tonne

annual production rate

Strict Environmental Conditions

Primary Ventilation Circuit

N

Derryville

Main North

Main Zone

Bog Zone

CrusherFAS & Alimak

haulage

Bog Zone

The Bog Zone is a new addition to the The Bog Zone is a new addition to the Lisheen Mine which extends the Lisheen Mine which extends the underground footprint eastwards.underground footprint eastwards.

The feasibility study completed in 2003 The feasibility study completed in 2003

Planning permission received from North Planning permission received from North Tipperary County Council a year later.Tipperary County Council a year later.

Developed from 2004-2007Developed from 2004-2007

Provides 43% of future metal for LisheenProvides 43% of future metal for Lisheen

Mine Planning & Ventilation – Feasibility Stage 2003

N

Bog West

Bog East

VR6

VR7 VR8

Bog CentralScale100m

haulage

Lisheen Property Boundary

Bog Central

Bog West Stopes

Bog East Upper Lens

Bog East Lower Lens

Mine Planning & Ventilation - Bog Zone Mine Design Change 2006

Mining MethodMining Method mm33/s//s/MtpaMtpa

Large open stopes Large open stopes >0.5 Mtpa>0.5 Mtpa

160160

Small open stopes Small open stopes <0.5 Mtpa<0.5 Mtpa

240240

Room and PillarRoom and Pillar 200200 N

Bog West

Bog Central

Bog Easthaulage

VR7 VR8

VR6

Scale100m

New Auxiliary Fan Sizes 2007

Lisheen standard 0.04 m³/s per kW of Lisheen standard 0.04 m³/s per kW of rated engine powerrated engine power

Average heading requires 24 m³/s Average heading requires 24 m³/s o based on a 250 kW loader and a 40 based on a 250 kW loader and a 40

tonne (350 kW) trucktonne (350 kW) trucko standard auxiliary fans employed meet standard auxiliary fans employed meet

this requirementthis requirement Loading 50 tonne (450 kW) trucks with Loading 50 tonne (450 kW) trucks with

350 kW loaders350 kW loaderso target delivery airflow of 34 m³/starget delivery airflow of 34 m³/s

Larger auxiliary fans requiredLarger auxiliary fans required

Reevaluate Total Volume Flow

New standard for the Bog Zone auxiliary fansNew standard for the Bog Zone auxiliary fans

Determine the overall amount of air needed Determine the overall amount of air needed based on:based on:o the total number of working headings in Bog the total number of working headings in Bog

Zone Zone o the size of the fleet and crewthe size of the fleet and crewo the overall mining schedulethe overall mining scheduleo increase amount of air on haulageincrease amount of air on haulage

Amount of air needed is 200mAmount of air needed is 200m33/s/s

40% increase of total airflow required to mine 40% increase of total airflow required to mine Bog ZoneBog Zone

OMG! 40% More Air Required!!

VR6 and VR7 have been raiseboredoContractor to

return in four months to complete VR8

Lisheen does not have a current ventilation modeloConsultant hired

to perform model simulations

External Review and Modeling

VR8 escapewayVR8 escapeway Planned 3m Planned 3m

diameterdiameter 100 m100 m33/s and /s and

ladderwayladderway Revise plan to 4m Revise plan to 4m

diameterdiameter

External Review and Modeling

BZ haulage airflow directionBZ haulage airflow direction Total volume through VR7Total volume through VR7 Operating CostOperating Cost

o minimize electrical powerminimize electrical power cost – US $1.1 million/yrcost – US $1.1 million/yr capped by electrical gridcapped by electrical grid

N

Bog West

Bog Central

Bog Easthaulage

VR7 VR8

VR6

Scale100m

Jet-thrust

External Review and Modeling

N

Staged Implementation

In-house waste development - November 2004In-house waste development - November 2004 Auxiliary force ventilationAuxiliary force ventilation In house waste development 50m a monthIn house waste development 50m a month

o Bog Zone full production by September 2007Bog Zone full production by September 2007

Scale100mN

Aux. force fan

Aux. exhaust fan

Staged Implementation – Accelerated Development

Contractor start development August 2006 November 2006 Raiseboring of VR6 complete Auxiliary vent move up

Scale100m

N

VR6

Staged Implementation – Accelerated Development

Underground access VR7 complete February 2007

April 2007 raiseboring VR7 finished Auxiliary vent move up

o In-line booster fan

Scale100mN

VR7

VR6

In-line booster fan

Staged Implementation – Accelerated Development

Underground access VR8 complete July 2007 Raiseboring VR8 finished September 2007 Raiseboring VR7A complete October 2007

VR6

VR7

Scale100mN

VR8VR7A

Staged Implementation – Main Fan

QuotationQuotation Operating CostOperating Cost

o minimize electrical powerminimize electrical power cost – a single kW US $1400/ yrcost – a single kW US $1400/ yr capped by electrical gridcapped by electrical grid

Procurement IssuesProcurement Issues Installation planned August 2008Installation planned August 2008

Staged Implementation – Secondary Egress

Cost benefit analysis of ladderway vs refurbished Alimak

December 2007 VR8 supported

Refurbished Alimak to be installed end of this month

Conclusions

Ventilation plans must be reevaluated and Ventilation plans must be reevaluated and changed as conditions evolve. changed as conditions evolve. o realize a better distribution of airflow, realize a better distribution of airflow,

optimized secondary escape way, reduced optimized secondary escape way, reduced contaminants, and reduced total power contaminants, and reduced total power requirements. requirements.

Supply chain problems can greatly affect Supply chain problems can greatly affect timeline.timeline.

Computerized ventilation modeling and Computerized ventilation modeling and planning for staged implementation should planning for staged implementation should never be underestimated. never be underestimated.

Thank you