Surface miner

Surface miner

2. Continuoussurfaceminer(CSM)isbasicallyacuttingmachine
usedinsurfacemines.Thesemachineshavebeendeveloped
during1970sprimarilyforextractionofthinseams(notless
than2.5cmthick)andselectiveremovalofthindirtbands
presentinseams.
INTRODUCTION

3. ☻Theconventionalmethodofminingincludes–
Drilling,Blasting,andFaceloading.
☻Evenenoughtechnologydevelopmenttookplaceto
takecareofflyrock,stillthereisaproblems.Andthe
secondforemostiscosteffectiveminingandalso
qualitycontrol.
☻Toovercometheaboveproblems,aseriesofresearch
anddevelopmentledtothedevelopmentofnew
technologyknownasBlastfreeminingbySURFACE
MINER.

4. ☻A significant improvement can be achieved in the following
area-
> Produce clean and high quality material.
> Deposit can be exploited fully.
> Reduction in transportation cost and production
process.
> Environmental friendly mining.
☻It also takes care of both safety part and economics in
mining
Some direct benefits are –
1.Mining with out blasting, therefore no need for drilling.
2. Insitu crushing is feasible & further sizing before conveying
on to the truck is possible.

5. 3. Surface miners have a unique conveying system by
which the mined material is directly loaded onto the truck /
dumper.
4. The haul road preparation and maintenance in deposit are
reduced. Even some times its not required.
This system has special advantage of selective mining
Less coal loss and dilution.
Improved coal recovery especially in areas sensitive to
blasting.
Less stress and strain on trucks due to minimum impact of
the excavated material.
Primary crushing and fragmentation of coal reduces the
capacity requirements for coal washing / preparation
plants.

6. The surface miner mainly consists of 5 units:
1.Mainframe:It consists of operators cabin, supporting
frames, Boom counter weight, Slewing ring etc.
2.Conveying Unit:It consists of two stage conveyors,
one carries the material from the cutting drum and
discharges on the boom conveyor. This conveyor in turn
conveys it on to the trucks.
3.Drive Unit:It consists of a diesel operated engine
whose power is transmitted to the cutting drum via
robustic belts drive. And it consists of hydraulic system
to operate other units.
4.Crawler Unit:Based on the design it may be single pair
crawler or two pair crawler.

8. ☻The most important
parameter is the cutting tool.
☻The selection of right cutting
tool is essential for good
cutting performance & high life,
since, it constitute a major
portion of operation cost of the
machine.
☻The cutting depth can be
regulated by automatic leveling
system mounted on the machine, the pre-selected cutting depth is main
-tained either automatically or manually.
☻Based on the cutting principle and position of the drum, the surface
miner is classified in three types.
5. Cutting Unit:

9. 1.Machine with middle drum configuration
☻In these type of machines the cutting drum is positioned below the
machine in between the front and the rear crawlers, cutting picks are
fitted on a drum and having the depth of cut 500 to 600 mm

10. 2. Machine with front boom cutting drum.
☻In these type of machines cutter drum fitted with picks is mounted on a
Boom, like road headers. Due to longer boom the cutting force of the
machine is limited.

11. 3. Machine with front cutting wheel
☻I this types of m/c, several bucket wheels are arranged in tandem &
cutter picks are fitted on lip of each bucket to form the cutting drum,
which is positioned in front of the m/c.
☻The m/c can exert huge force in cutting both hard coal and rock as the
bucket wheel drum is close to the m/c and the reaction of cutting force is
directly transferred to the ground through a hydraulically loaded dozer blade
behind the bucket wheels.

12. Working Principle of Surface miner.
☻The surface miner is crawler-mounted machine having a
cutting drum located b/w two sets of crawlers and position
-ed at the center of the machine.
☻The drum is lowered and raised by hydraulic system with
powerful hydraulic motors thereby varying the depth of cut
☻The material cut is loaded onto the primary and secondary
discharge conveyors for loading the same on to the
loading / transporting equipment.
☻The rear crawler travel at lower level then the front
crawlers to adjust to the required depth.

13. Precise
cutting depth
Clean, level and
stable surface
Continuous
cutting
Crushed
aggregate
Direct
loading

14. InWirtgenSurfaceMiner,atypeofCSM,acuttingdrum,with
specifiednumberofreplaceablepicksmountedonitarrangedinform
ofhelix,isfittedbelowthemachinebodyinbetweenthefrontandrear
crawlers.Whenthemachineworks,thehydraulicallycontrolleddrum
rotatesinup-cuttingdirection.Thecuttingdrumisgenerallykeptin
horizontalpositionduringcutting,butcanbeinclinedtosomedegree
bycontrollingthehydraulicramstofacilitatecuttingofinclined
seams.Duringitsworking,thecuttingdrumrotatesinanup-cutting
directionandalayerofpredeterminedthickness(maximumthickness
dependsonthemachinemodel)ofthedepositiscutandcrushedin
betweenthepicks.The“ElectronicDepthControllerSystem”fittedin
themachinecontrolsthethicknessofcutslice/slices.Thewidthofthe
cutsliceissameasthelengthofthecuttingdrum.Themethodsof
workingsofsurfaceminercanbeclassifiedbasedon–(i)sequenceof
extractionofstrips,(ii)modeoftraveland(iii)modeofloading.
Methods of work using continuous Surface Miner

15. Method of working
Based on sequence of extraction of strips
•Wide bench method
•Block mining method
•Stepped cut method
Based on mode of travel
•Empty travel method.
•Turn back method.
•Continuous mining method.
Based on loading:
Direct truck loading
Indirect loading

16. Methods of working based on the
Sequence of Extraction of Strips
The working methods of Wirtgen Surface Miner,
based on the sequence of extraction of strips may
be classified into three categories –Wide Bench
Method, Block Mining Method and Stepped Cut
Method.

17. Thewidebenchmethodisgenerallyusedwhenthewidth
ofthemineralbenchisnotveryhigh.Inthismethod,
firsttheuppermostlayerofthewholewidthofthebench
isextractedinnumberofslicesfollowedbythe
extractionofthenextlayerandsoontillthefullheight
ofthemineralbenchisextracted.
42 29
28 20 15
14 11 7 321
O/B
Spoil
Coal
seam
Wide Bench Method
Wide Bench Method

18. Theblockminingmethodisadoptedwhenthemineralbenchis
sowidethattheextractionbywidebenchmethodisnot
suitable.Inthismethodthebenchwidthissuitablydividedinto
numberofblocks,andthentheblockfromtheedgesideofthe
benchisextractedfirstforthefullheightofthebenchin
numberofslicesfollowingasequencesimilartothatofwide
benchmethod.Aftercompletionofoneblockthenextadjacent
blockisextractedandtheprocesscontinuestillthewholebench
isextracted.
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
Block Mining Method

19. Thesteppedcutmethodisusedwhenexcessmoisture/wateris
presentinthemineralbenchthatcreatesprobleminextracting
theslices.Inthismethodalsothebenchisfirstdividedinto
suitablenumberofblocksandthentheindividualslicesareso
extractedthatitformsanumberofsmallstepsonthemineral
bench.Theformationofstepsfacilitatesthedrainagefromthe
mineralbenchtherebyimprovingthemachineefficiency.
Stepped Cut Method
O/B
Spoil
Coal Seam
Stepped cut Method
1
5
6
60
16
15 11
10
26
25
20
2136
35 31
30
46
45 41
40
56
55 51
50

20. TheworkingmethodsofWirtgenSurface
Miner,basedonthetravelmodefor
extractionofslicesofsamelayer,may
beclassifiedintothreecategories–
EmptyTravelBackMethod,TurnBack
MethodandContinuousMiningMethod.
Methods of working based
on the Travel Mode

21. Intheemptytravelbackmethod,thesurfaceminerstarts
excavatingaslicefromoneendofthebenchandmovesupto
theotherend.Aftercompletionofonefullcut,themachine
travelsbackemptytothestartingend,andsetsforanewcut
intheadjacentparallelslice,andtheprocesscontinues.The
processisgenerallyadoptedunderoneormoreofthe
followingconditions.
Availablelengthofthebenchissmall(notmore
than200m)
Turningtimeofthemachineismorethanthe
emptytraveltime.
Themachineturningisdifficultatthecutends.
Empty Travel Back Method

22. Empty Travel Back Method
Production travel
Empty travel

23. Intheturnbackmethod,thesurfaceminerstartscuttinga
slicefromoneendofthebenchandmovestotheotherend.
Afterthecutiscompletethemachineturnsbackthereto
startafreshcutadjacentandparalleltothepreviouscut.In
thiswaytherequirednumberofslicesareextracted.The
methodismostwidelyacceptedandusedprovidedthe
followingconditionsexist.
Availablelengthofthebenchismorethan200m.
Turningtimeislessthantheemptytraveltimeforthe
machine.
Requiredturningspaceisavailableatthecutends.
Turn Back Method

24. Turn BackMethod

25. Incontinuousminingmethod,themachinemoves
withcuttingthematerialandnearthepitendsit
takesturnwithagentleanglewhilestillcuttingthe
material.Thusthereisnodiscontinuityincutting
operation.Thisresultsinaroundshapeofthecut
areaparticularlyatthecutends.Theprocess
continuestillthecircular/ellipticalturningsbecome
sosharpthatthemachinecannottaketurnwhile
continuingthecuttingoperation.Thenthemachine
followstheturnbackmethodforminingtherestof
thematerialatthecentralportion.
Continuous Mining Method

26. Continuous Mining Method

27. Methods of working based
on the Loading Mode
Therearebasicallytwomodesofoperationpossibleby
WirtgenSurfaceMineronthebasisofloadingitcanadopt
–conveyorloadingandwindrowing.
Inconveyorloadingmode,thematerialthatiscutbythe
machineisdischargedbythedischargeconveyor,which
maydirectlyloadlargecapacitydumpersorshiftable
benchconveyor,orside-castit.Ontheotherhand,in
windrowingmode,themachinecutsthematerialandthe
cutmaterialisallowedtoheapbehindthemachineinform
ofwindrows.Thecutmaterialfromthewindroworthe
side-castedheapcanbeloadedlaterconvenientlyto
dumper/tipperbysomeloadingequipmentlikeFEL.

28. LOADING OPTIONS
DIRECT TRUCK
LOADING INDIRECT LOADING
WINDROW SIDE CASTFRONT LOADING REAR LOADING

29. DIRECT TRUCK LOADING

30. INDIRECT LOADING
Windrow

31. SIDE CAST

32. COMPARISON OF LOADING METHODS
ADVANTAGES DISADVANTAGES
Direct
loadingNo re-handling of material required
Larger working area required for truck
Production affected by truck exchange
Belt wear
Side cast
Blending of materials in the mine
Stockpile of material in the mine
No waiting for trucks
Restricted to 3-5 cuts
Belt wear
Material has to be re-handled
Material prone to absorb water when
lying on ground
Windrow
No waiting for trucks
No belt wear
Higher production rates than
conveyor loading
Coarser material
Better selectivity on steep inclined
seams
Larger working area required
Material has to be re-handled
Material prone to absorb water when
lying on ground