1. Case study – ventilation planning for Bog Zone, Lisheen Mine
Kristen Hopperstead

2. Ventilation in mine design process Feasibility Design changes
Quantify amount of air required
Impact of larger mobile equipment fleet
Auxiliary circuit
Main ventilation circuit
Secondary Egress
Impacts shaft design
Implementation
staged implementation
Conclusions
Introduction

3. Location

4. Lisheen’s Vital Statistics
Cool, wet climate
352 Employees from 14 countries
Underground Zinc and Lead Mine
High grade
Mine life
1.6 million tonne annual production rate
Strict Environmental Conditions
Welcome to Ireland
The Lisheen mine is located approx half way between Dublin and Cork.
It is an underground mine containing very high grades of Zinc and Lead ore
The mine was opened in 1999 and we are expected to run until 2014
We have a very cosmopolitan and diverse workforce of over 350 employees who come from 14 different countries
We mine in the order of 1.6m tones a year
We operate under one of the most stringent Environmental Conditions of any of the other Anglo Mines
Lisheen’s Vital Statistics

5. Primary Ventilation Circuit
Main North
Derryville
Bog Zone
haulage N
The finished product of Zinc and Lead Concentrates are ultimately shipped to smelters around the world
What remains after the process is waste and this is what's called Tailings.
It is disposed of in a combination of two different ways.
It can be pumped out onto our Tailings Management Facilitiy which we call the TMF.
The TMF is Or
It can be pumped back down underground as Backfill Tailings.
This involves mixing the tailings with ordinary cement in the Backfill Plant and pumping down to the mined out voids underground
Crusher
FAS & Alimak
Main Zone
Primary Ventilation Circuit

6. The feasibility study completed in 2003
The Bog Zone is a new addition to the Lisheen Mine which extends the underground footprint eastwards.
The feasibility study completed in 2003
Planning permission received from North Tipperary County Council a year later.
Developed from
Provides 43% of future metal for Lisheen
Bog Zone

7. Mine Planning & Ventilation – Feasibility Stage 2003
Bog Central
Scale N
100m
Bog West
VR6
Bog East
haulage
VR8
VR7
Lisheen Property Boundary
Mine Planning & Ventilation – Feasibility Stage 2003

8. Bog West Stopes
Bog East Upper Lens
Bog Central
Bog East Lower Lens

9. Mine Planning & Ventilation - Bog Zone Mine Design Change 2006
Mining Method
m3/s/Mtpa
Large open stopes >0.5 Mtpa
160
Small open stopes <0.5 Mtpa
240
Room and Pillar
200 N
Scale
Bog Central
100m
VR6
Bog West
Bog East
haulage
VR7
VR8
Mine Planning & Ventilation - Bog Zone Mine Design Change 2006

10. New Auxiliary Fan Sizes 2007
Lisheen standard 0.04 m³/s per kW of rated engine power
Average heading requires 24 m³/s
based on a 250 kW loader and a 40 tonne (350 kW) truck
standard auxiliary fans employed meet this requirement
Loading 50 tonne (450 kW) trucks with 350 kW loaders
target delivery airflow of 34 m³/s
Larger auxiliary fans required
New Auxiliary Fan Sizes 2007

11. Reevaluate Total Volume Flow
New standard for the Bog Zone auxiliary fans
Determine the overall amount of air needed based on:
the total number of working headings in Bog Zone
the size of the fleet and crew
the overall mining schedule
increase amount of air on haulage
Amount of air needed is 200m3/s
40% increase of total airflow required to mine Bog Zone
Reevaluate Total Volume Flow

12. VR6 and VR7 have been raisebored
Contractor to return in four months to complete VR8
Lisheen does not have a current ventilation model
Consultant hired to perform model simulations
OMG! 40% More Air Required!!

13. External Review and Modeling
VR8 escapeway
Planned 3m diameter
100 m3/s and ladderway
Revise plan to 4m diameter
External Review and Modeling

14. External Review and Modeling
BZ haulage airflow direction
Total volume through VR7
Operating Cost
minimize electrical power
cost – US $1.1 million/yr
capped by electrical grid
Scale N
Bog Central
100m
Bog West
Jet-thrust
VR6
Bog East
haulage
VR7
VR8
External Review and Modeling

15. External Review and Modeling

16. Staged Implementation
In-house waste development - November 2004
Auxiliary force ventilation
In house waste development 50m a month
Bog Zone full production by September 2007
Scale N
100m
Aux. exhaust fan
Aux. force fan
Staged Implementation

17. Staged Implementation – Accelerated Development
Contractor start development August 2006
November 2006 Raiseboring of VR6 complete
Auxiliary vent move up N
VR6
Scale
100m
Staged Implementation – Accelerated Development

18. Staged Implementation – Accelerated Development
Underground access VR7 complete February 2007
April 2007 raiseboring VR7 finished
Auxiliary vent move up
In-line booster fan
Scale N
100m
In-line booster fan
VR6
VR7
Staged Implementation – Accelerated Development

19. Staged Implementation – Accelerated Development
Underground access VR8 complete July 2007
Raiseboring VR8 finished September 2007
Raiseboring VR7A complete October 2007
Scale N
100m
VR6
VR8
VR7A
VR7
Staged Implementation – Accelerated Development

20. Staged Implementation – Main Fan
Quotation
Operating Cost
minimize electrical power
cost – a single kW US $1400/ yr
capped by electrical grid
Procurement Issues
Installation planned August 2008
Staged Implementation – Main Fan

21. 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
Staged Implementation – Secondary Egress

22. Supply chain problems can greatly affect timeline.
Ventilation plans must be reevaluated and changed as conditions evolve.
realize a better distribution of airflow, optimized secondary escape way, reduced contaminants, and reduced total power requirements.
Supply chain problems can greatly affect timeline.
Computerized ventilation modeling and planning for staged implementation should never be underestimated.
Conclusions

23. Thank you