THE BEACONSFIELD MINE RESCUE

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THE BEACONSFIELD MINE RESCUE

• THE ROLE OF
• THE SURVEYORS
• 25 April to 9 May 2006 Simon Arthur

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THE BEACONSFIELD MINE RESCUE

• The Beaconsfield Mine tragedy on ANZAC Day 2006
  saw what human endeavour could achieve in a time
  of crisis.
• The successful rescue was a result of meticulous
  planning, teamwork, patience and the commitment
  to utilise whatever resources that were available
  to enable a successful outcome.
• No stone was left unturned.

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THE BEACONSFIELD MINE RESCUE

• During the course of the rescue many people of
  varying skills were put to the test, not least of
  which were the mine surveyors.
• A brief summary of the mining method employed in
  the vicinity of the rock fall and a chronological
  account of the surveying activities during the
  rescue will be given in this presentation.

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OVERVIEW OF THE MINING METHOD

• The Beaconsfield Mine tragedy and associated
  rescue was centred around the 925 Sill Drive.
• The 925 Level is situated approximately 925
  metres below the surface at the mine headframe.
• See Fig. 1 for a plan showing the location of the
  925 Level relative to the headframe (Hart Shaft)
  and the township of Beaconsfield.

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OVERVIEW OF THE MINING METHOD
Fig. 1 Beaconsfield township - green shading
indicates the 925 Level.
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OVERVIEW OF THE MINING METHOD

• The mining method used in this region of the mine
  is referred to as the Modified Avoca Mining
  Method.
• This method involves initially mining three sill
  drives (horizontal mining) and then stoping
  between the sill drives (vertical drilling and
  blasting) as shown in Fig. 2.
• The 925 Sill drive is the central sill drive of
  the 940 stoping block.

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OVERVIEW OF THE MINING METHOD
Fig. 2 A schematic of the long section view of
the 940 Stoping Block
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OVERVIEW OF THE MINING METHOD

• Fig. 3 represents the long section after the
  ANZAC Day rock fall, showing the extent of the
  rock fall (broken line not surveyed), the
  extent of mining, the rock fill placed and the
  approximate location of vehicles in the 925 sill
  drive. Just prior to the rock fall a mesh
  barricade was being erected back from the brow of
  the open stope so that a panel in the 925 Lift 1
  could be backfilled so that stoping could take
  place in the 915 Level.

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OVERVIEW OF THE MINING METHOD
Fig. 3 Long section view of the 925 sill drive
after the rock fall
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THE MINE SURVEYORS ROLE

• Over the course of the rescue mission a variety
  of tasks were carried out. These tasks are no
  different to those carried out during normal day
  to day mining operations on this site and other
  sites. In this presentation I will outline the
  survey teams involvement during the rescue in a
  chronological manner without going into great
  detail about the surveying techniques employed.
• The fortnight can be broken up into two parts.
  Firstly the first five days after the rock fall
  and secondly the nine days after two of the
  missing miners were found alive.

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THE MINE SURVEYORS ROLE

• The first five days Wednesday 26th to Sunday
  30th of April 2006
• In the early hours of Wednesday 26th of April
  2006, Mine Surveyor Peter Wylie was called into
  work to start producing the most current plans
  and section views in the vicinity of the 925
  Level to enable the Emergency Operations Control
  Group (EOCG) to determine what options were
  available.

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THE MINE SURVEYORS ROLE

• After careful deliberation and investigation by
  the EOCG it was decided that an alternative
  access to the location where three miners, Brant
  Webb, Todd Russell and Larry Knight were last
  seen working, was needed.
• Once the design was decided upon we were required
  to produce sections along the alignment.
• Once extra ground support was installed the new
  access drive was marked up and an alignment laser
  installed to guide the mining of the drive.

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THE MINE SURVEYORS ROLE

• Communicating progress to the miners families
  and mining of the access drive to design meant
  that 24 hour a day survey coverage was required.
• New survey control was established in the
  vicinity of the access drive.
• A refinement of the breakthrough of the new
  access drive into the 925 Sill Drive meant more
  sections and the installation of a new alignment
  laser were required.
• At approximately 530 pm on Sunday 30th April
  verbal contact was made with Brant Webb and Todd
  Russell. Mining ceased while the EOCG considered
  their options.

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THE MINE SURVEYORS ROLE

• The last nine days Monday 1st to Tuesday 9th of
  May 2006
• In the early hours of Monday the 1st of May the
  last cut fired in the access drive was surveyed.
  A plan of the drive was produced and the
  co-ordinates of a probe hole to target the
  trapped miners last known location were
  determined.

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THE MINE SURVEYORS ROLE

• The probe hole was then set out. The probe hole
  which hit its target first time was reamed and
  lined with some PVC piping, thus establishing a
  safe means of communicating and providing
  supplies to the miners.
• Initially it was decided to access the trapped
  miners by mining a small airleg drive following
  the left hand wall of the larger access drive. In
  order to mine this smaller drive a new laser was
  installed to control the mining. Fig 4. below is
  the plan produced and supplied to the sites
  Mining Department to ensure correct mining of the
  rescue drive.

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THE MINE SURVEYORS ROLE
Fig. 4 Plan used for ensuring mining to design.
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THE MINE SURVEYORS ROLE

• After a lengthy deliberation the EOCG decided
  that a slightly inclined, 1.07 m diameter
  raisebore hole would be mined instead.
• A collar survey (location, direction dip) of
  the lifeline hole was carried out. Information
  obtained from the two miners along with the
  details obtained from the collar survey of the
  lifeline hole enabled a better estimate of the
  location of the trapped miners to be determined.

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THE MINE SURVEYORS ROLE

• The raisebore hole was designed to come in
  directly below the men and telehandler basket.
• A concrete pad design and the correct alignment
  for the raisebore hole had to be determined.
• The finished surface level of the concrete pad
  was marked up to enable the rig to be set up
  close to the designed inclination of the
  raisebore hole (approximately 2 degrees
  difference). Two dynabolt hooks were placed in
  the drive walls on the correct orientation to
  enable the raisebore rig to be set up to hit the
  designed target.

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THE MINE SURVEYORS ROLE

• The concrete pad was surveyed as soon as the pad
  was completed.
• Once the concrete had cured the raisebore rig was
  set up using the alignment dynabolts and the
  designed dip of the proposed hole. Prior to
  bolting down, the rig was surveyed to confirm
  that the set up was correct.
• After the rig was bolted down another survey was
  undertaken to confirm the orientation and dip of
  the rig were correct.

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THE MINE SURVEYORS ROLE

• The raisebore operators were then given the go
  ahead to collar the drill head. A final survey of
  the drill rods once the drill head had been
  collared was required. The survey indicated the
  hole orientation had moved 1 degree to the west
  and the hole dip lifted by 1 degree.

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THE MINE SURVEYORS ROLE

• On completion of the smaller raisebore pilot
  hole, surveys of both the lifeline hole and the
  pilot hole were undertaken. This was critical to
  ensure that the lifeline hole to the two miners
  was not compromised in any way.
• The raisebore pilot hole was then reamed out to
  its full size of 1.07 m diameter. Early on Sunday
  (7th May) morning a survey of the raisebore
  tunnel was completed. The survey was processed,
  3D solids created and plans including section
  views produced, which were forwarded to the EOCG.

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THE MINE SURVEYORS ROLE

• The remaining 1.4 metres of tunnelling was
  completed in two parts using a material call PCF
  (penetrating cone fracture). A survey was
  completed after the first firing occurred.
• The final survey was completed after the tunnel
  was bogged clean following the second firing.
  At the same time a reference point was marked up
  on the backs of the tunnel. This point was later
  used for locating probe holes drilled upwards to
  break into the 925 sill drive.

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THE MINE SURVEYORS ROLE

• The survey was processed and a complete 3D solid
  model of the rescue tunnel, access drive, the
  lifeline hole and the 940 stoping block
  generated. Plans and sections were produced so
  that the EOCG could determine how best to proceed
  to ensure the safe rescue of the trapped miners.

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THE MINE SURVEYORS ROLE
Fig. 6 - Section view of Access Drive, Rescue
Tunnel, Comms/food hole, Stope and Raisebore rig.
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THE MINE SURVEYORS ROLE
Fig. 7 a 3D solid model of the rescue site
generated in Surpac.
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THE MINE SURVEYORS ROLE

• Probe holes were drilled with one breaking
  through that the two miners could touch. A few
  hours later in the early hours of the 9th of May,
  2006 the two miners were freed and the rescue
  mission successfully completed.

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FACTORS THAT CONTRIBUTED TO A SUCCESSFUL OUTCOME

• The involvement of the BMJV mine surveyors was
  obviously essential to the overall success of the
  rescue mission. The survey team formed part of
  the collective rescue team comprised of the BMJV
  workforce, other mining professionals, miners and
  mines rescue team from other mines and emergency
  services personnel that facilitated the rescue of
  the two miners.
• There were a number of factors from a surveying
  point of view that enabled the BMJV mine
  surveyors to undertake their work in an effective
  manner with a high degree of confidence.

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FACTORS THAT CONTRIBUTED TO A SUCCESSFUL OUTCOME

• Of great benefit to the overall success of the
  rescue was that a comprehensive CMS survey of the
  925 Lift 1 stope completed on the morning of the
  25th of April.
• The application of wall stations in conjunction
  with the Leica TCRA 1105 theodolite and its on
  board free station" software.

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FACTORS THAT CONTRIBUTED TO A SUCCESSFUL OUTCOME

• Our role was confined to providing survey
  expertise during the rescue.
• Comprehensive survey pickups of all headings,
  particularly the production headings. 3D solids
  of all excavations, in particular active
  production headings are generated monthly along
  with the updating of the mine long section.
• Regular Check Surveys of the primary survey
  network.

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CLOSING OUT

• At the time of submission of this presentation it
  is still not possible to comment on the rescue or
  other related issues or provide additional plans
  or images.
• I would like to thank my fellow Mine Surveyors,
  Damian Gardiner and Peter Wylie for their
  unwavering efforts during the rescue and those
  who extended support and praise at the completion
  of the rescue.

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CLOSING OUT

• The overall success of the rescue was a result of
  a focused, committed effort by every person on
  site at Beaconsfield, lead by Mine Manager,
  Matthew Gill and his management team.
• The loss of Larry Knight during the tragedy and
  the impact on his partner Jacquie and their
  children is never far from our thoughts.