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HIGHWALL MINING

Presented by

  P.Prudhviraj

  N.Vijender 

  S.Rajesh

  J.venkateshwarlu

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Highwall Mining Driing !arallel roadways into highwall" coal seam using

remote controlled mining machinery # $%% '%% m de!th

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Highwall Mining (ystems )*+ cont,

Addcar (ystem  Launch ehicle  Coneyor cars

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Highwall Mining (ystems )$+

Archeyor system

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Highwall Mining

Highwall Mining (ystems )-+

Auger system

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Geotechnical Issues & .ating

  /nsu!!orted s!an sta0ility

  Pillar sta0ility  Panel (ta0ility

  Case studies

  Design guidelines

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Highwall Mining

/nsu!!orted (!an (ta0ility

  1y!ical 2ailure mechanism  # delamination & sna!through

  (im!le analytical  # thic3ness o2 roo2 !late4 54

  Pro0a0ilistic a!!roach  .ealistic !rediction  # Geology4 roc3 !ro!erties

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Highwall Mining

Pillar (ta0ility

 La0 testing o2 coal strength

  6m!irical a!!roach

  Pillar sta0ility modelling  A!!lications and eri2ication in 2ield

Pillar Strength v. Width/Height

0

5

10

15

20

25

0 1 2 3 4 5

Pillar Width/Height

   P   i   l   l  a  r

   P  e  a   k

   S   t  r  e  s  s

   (   S   t  r

Proposed HWM

Wagner 

Bienawski

 Average Trendline

0.36W/h)0.6!"6.00   +=Strength

0.36w/h)0.6!"6.00   +=Strength

0.!!w/h#w$0.6%W   +=

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Design Guidelines

*' 3ey 2actors are considered4

e,g, roo2 condition8 mine resere

etc,8

9ey 2actors are weighted

di22erently in HMI8

/ncertainty on :udgement is

incor!orated,

A gien site has two inde;

alues< HMI rating4 con2idence

leel,

.ecommendation is gien 2or

any HMI"Con2idence ratings,

0

10

20

30

40

50

60

70

80

0

100

0 10 20 30 40 50 60 70 80 0 100

Highwall Mining Index (HMI)

   C  o  n   f   i   d  e  n  c  e   L  e  v  e   l   (      )

!

!ood si"e #or $HM

%ining

"

Possi&l' a good si"e

#or $HM %ining( More

in#or%a"ion is need(

#)i"e apparen"l' *ns*i"a&le

#or $HM %ining( +*r",er

eval*a"ion %a' &e needed i#

new in#or%a"ion is availa&le

$

)i"e *ns*i"a&le #or

$HM %ining(

%ransition

&one

-.a%ple pi" 1

&  Highwall Mining Inde; )HMI+ has 0een deelo!ed

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Guidance Control )*+

Driing !arallel roadways  remote miner $%% to '%% m de!th

Pro0lems Cutthrough=s connection Pillar 2ailure 2re>uent roo2 2alls Limited !enetration de!th

panel 4

/4167

panel 3

/2140

panel 2

/1120

panel 1

/110

$raks on "op

o# ",e ,ig,wall

)*rve' da"a

$raks on ",e

#ae o# ",e

,ig,wall

&serva"ion

or",

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Guidance Control )$+ Problems to solve

Uncertainty in pillar size

Frequent cut-throughs

Reduced penetration depth

pillar/panel failure

Guidance system Military grade nertial !avigation "ystem

ndependent odometer

#ontrolling computers

$perator displace and interface

%chievements Used in every &'M system in %ustralia

!o mining equipment lost due to collapse

Penetration depths increased - ()*m to )+*m

 

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Failures )*+

Panel 2ailure

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?e2ore A2ter

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Local !anel 2ailure at 5arra0ee MinePanel 2ailure at /lan Mine

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Failures )$+

Panel 2ailure

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Lac3 o2 site inestigation

Poor 3nowledge on s!an sta0ility

Inade>uate !illar design

Poor guidance control

Critical !anel width

Lac3 o2 3nowledge on insitu stresses

No monitoring and 2eed0ac3  

Factors contri0uting to !illar"!anel 2ailures

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Production Production @ * million tonnes !er year

6m!loyees # '% )High !roductiity # main adantage+

Continuous inert gas in:ection *'% l"s Penetration de!th # aries # *%% to '%% m )A -%%m+

 Gas issues

  (ta0ility issues 6ach roadway drien # almost in one day )or less+

Production share in Australia # *B

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Conclusions

Main attraction # high !roductiity and low cost

(uita0le 2or certain conditions # '%% m 0oundary

May lead to more 2ires and colla!ses Around '%B o2 e;traction

Creates !ro0lems 2or dee!er reseres

Production share in Australia # *B

Punch longwall # !re2erred 2or large reseres

 High !roduction and longer term iew

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1HAN9 57/