Surface mining methods

Surface mining methods

2. A PANORAMIC VIEW OF A SURFACE MINE

3. ANOTHER VIEW

4. Continuous Surface Miner
Continuoussurfaceminer(CSM)isbasicallyacutting
machineusedinsurfacemines.Thesemachineshavebeen
developedduring1970sprimarilyforextractionofthinseams
(notlessthan2.5cmthick)andselectiveremovalofthindirt
bandspresentinseams.

5. Methods of work using continuous Surface Miner
InWirtgenSurfaceMiner,atypeofCSM,acuttingdrum,with
specifiednumberofreplaceablepicksmountedonitarrangedin
formofhelix,isfittedbelowthemachinebodyinbetweenthefront
andrearcrawlers.Whenthemachineworks,thehydraulically
controlleddrumrotatesinup-cuttingdirection.Thecuttingdrumis
generallykeptinhorizontalpositionduringcutting,butcanbe
inclinedtosomedegreebycontrollingthehydraulicramsto
facilitatecuttingofinclinedseams.Duringitsworking,thecutting
drumrotatesinanup-cuttingdirectionandalayerofpredetermined
thickness(maximumthicknessdependsonthemachinemodel)of
thedepositiscutandcrushedinbetweenthepicks.The“Electronic
DepthControllerSystem”fittedinthemachinecontrolsthe
thicknessofcutslice/slices.Thewidthofthecutsliceissameas
thelengthofthecuttingdrum.Theextractionofslicesmaybe
accomplishedbyfollowingWideBenchMethodorBlockMining
MethodorSteppedCutMethoddependingonthesituation.

6. Wide Bench Method
Thewidebenchmethodisgenerallyusedwhenthe
widthofthemineralbenchisnotveryhigh.Inthis
method,firsttheuppermostlayerofthewholewidthof
thebenchisextractedinnumberofslicesfollowedby
theextractionofthenextlayerandsoontillthefull
heightofthemineralbenchisextracted.
42 29
28 20 15
14 11 7 321
O/B
Spoil
Coal
seam
Wide Bench Method

7. Block Mining Method
Theblockminingmethodisadoptedwhenthemineralbench
issowidethattheextractionbywidebenchmethodisnot
suitable.Inthismethodthebenchwidthissuitablydivided
intonumberofblocks,andthentheblockfromtheedgeside
ofthebenchisextractedfirstforthefullheightofthebenchin
numberofslicesfollowingasequencesimilartothatofwide
benchmethod.Aftercompletionofoneblockthenext
adjacentblockisextractedandtheprocesscontinuestillthe
wholebenchisextracted.
45
40
35
41
36
31
26
21
30
25
20 16
15 11
10 6
5 3 1
O/B
Spoil
Coal
seam
Block III Block II Block I
Block Mining Method

8. Stepped Cut Method
Thesteppedcutmethodisusedwhenexcessmoisture/water
ispresentinthemineralbenchthatcreatesproblemin
extractingtheslices.Inthismethodalsothebenchisfirst
dividedintosuitablenumberofblocksandthentheindividual
slicesaresoextractedthatitformsanumberofsmallstepson
themineralbench.Theformationofstepsfacilitatesthe
drainagefromthemineralbenchtherebyimprovingthe
machineefficiency.
4145
40 36
35 31
30 26
25 21
20 16
15 11
10 6
5 1
O/B
Spoil
Coal
seam
Block III Block II Block I
Stepped cut Method

9. Methods of working based
on the Travel Mode
TheworkingmethodsofWirtgenSurface
Miner,basedonthetravelmodeforextraction
ofslicesofsamelayer,maybeclassifiedinto
threecategories–EmptyTravelBack
Method,TurnBackMethodandContinuous
MiningMethod.

10. Empty Travel Back Method
Intheemptytravelbackmethod,thesurfaceminerstarts
excavatingaslicefromoneendofthebenchandmovesuptothe
otherend.Aftercompletionofonefullcut,themachinetravelsback
emptytothestartingend,andsetsforanewcutintheadjacent
parallelslice,andtheprocesscontinues.Theprocessisgenerally
adoptedunderoneormoreofthefollowingconditions.
Availablelengthofthebenchissmall(notmorethan200m)
Turningtimeofthemachineismorethantheemptytravel
time.
Themachineturningisdifficultatthecutends.
Empty Travel Back Method

11. Turn Back Method
Intheturnbackmethod,thesurfaceminerstartscuttingaslicefrom
oneendofthebenchandmovestotheotherend.Afterthecutis
completethemachineturnsbacktheretostartafreshcutadjacent
andparalleltothepreviouscut.Inthiswaytherequirednumberof
slicesareextracted.Themethodismostwidelyacceptedandused
providedthefollowingconditionsexist.
Availablelengthofthebenchismorethan200m.
Turningtimeislessthantheemptytraveltimeforthemachine.
Requiredturningspaceisavailableatthecutends.
Turn Back Method

12. Continuous Mining Method
Incontinuousminingmethod,themachinemoveswithcuttingthe
materialandnearthepitendsittakesturnwithagentleanglewhile
stillcuttingthematerial.Thusthereisnodiscontinuityincutting
operation.Thisresultsinaroundshapeofthecutareaparticularly
atthecutends.Theprocesscontinuestillthecircular/elliptical
turningsbecomesosharpthatthemachinecannottaketurnwhile
continuingthecuttingoperation.Thenthemachinefollowstheturn
backmethodforminingtherestofthematerialatthecentral
portion.
Continuous mining method