DEPILLARING DEPILLARING OF THE ANJAN HILL 0 SEAM WORKINGS

DEPILLARING DEPILLARING OF THE ANJAN HILL 0 SEAM WORKINGS Jaco J. van Vuuren Gerald Webster Gordon M c Cormack Sri N. Kumar R M T

R M T Mechanised Depillaring

Successful Mechanised Depillaring (stooping; pillar extraction) Is an Art, Not a Science! M T

Reasons for depillaring Utilize the coal reserves to its full potential Spontaneous combustion of coal Protect surface structures Prevent access M T Prove the technology

Mechanised Depillaring To be successful, it must be safe Discipline Quality of pillar and roof support Orderliness

Failure cannot be prevented, thus it must be controlled Correct design (, Management) Pillar design Overburden load Goaf conditions Lay-out, dimensions & sequence Understand mining limitations Primary support & secondary support Measure and adjust

Failure cannot be prevented, thus it must be controlled Experience of personnel (Mining personnel) Understanding depillaring process Able to evaluate conditions Discipline in extraction panel Follow cutting and pillar extraction sequence Make quick decisions within certain parameters Continuous process

Components of the process Macro Environment (Above seam) Overburden supported by pillars, fenders & snooks Topography Composition of overburden strata Width of panel and size of the goaf hanging up Cutting sequence M T

Components of the process Micro Environment (In seam) Cutting sequence Joints Sidewalls Systematic support Goaf edge support Width of junctions/intersections Hazardous areas/ No-go Areas M T

Macro Environment

Topography

Topography A Rise contour profile WNW - ESE

Topography and Lithology C H A - 6 E l e v a t i o n 7 8 1. 3 6 2 3 L e v e l, 2 R i s e E 7 5. 0 0 0 7 5. 0 0 0 781.36 S ludge 760.86 Sandstone (M GD ) 741.36 S h a le 736.14 C oal #0 top 734.68 727.61 Sandstone (C G D ) 734.06 714.21 C oal #1 733.86 C o a l # 0 m id 712.51 S a n d s to n e ( C G D ) 732.33 S h a le C oal #0 bottom 691.86 727.61 C H A - 5 E l e v a t io n 8 0 0. 1 0 1 5 L e v e l, 3 R is e E 7 5. 0 0 0 7 5. 0 0 0 769.6 733.9 731.9 800.10 Sludge 775.1 776.1 C oal 774.6 S h a le S ludge 741.6 C oal #0 bottom S andstone (M G D ) 735.05 S h a le 732.3 C o a l # 0 to p 726.0 731.1 C arbonaceous shale C o a l # 0 m i d S h a le S andstone 667.0 7 5. 0 0 0 7 5. 0 0 0 C H A - 7 E l e v a t i o n 7 9 1. 2 6 8 L e v e l, 5 R i s e W 791.26 S andstone 749.26 S h a le 732.46 722.56 C oal #1 local 720.66 S h a le 720.31 S andstone (M G D ) Sandstone (M GD ) 742.43 S h a le 741.15 C oal #0 top 739.76 C arbonaceous shale 739.66 C o a l # 0 m i d S hale 738.50 C oal #0 bottom 736.41 660.51 661.26 657.06 S andstone (M G D ) 655.51 637.76 C oal seam local S h a le C oal #1 C H A - 8 E l e v a t io n 8 7 5. 2 2 2 l e v e l, 1 R is e W 8 7 5. 2 2 S a n d s t o n e M T 8 0 3. 7 2 8 0 6. 7 2 C la y 8 0 2. 7 2 S h a le 7 8 7. 2 2 S a n d s t o n e 7 8 1. 7 2 S h a le S a n d s t o n e C o a l # 1 lo c a l 7 3 4. 2 2 7 2 0. 4 2 7 1 8. 5 4 7 0 6. 7 2 S a n d s t o n e ( F G D ) S a n d s t o n e 7 4 7. 7 2 C la y 7 4 5. 2 2 7 4 2. 4 7 C a r b o n a c e o u s s h a le C o a l # 0 t o p 7 4 1. 4 C a r b o n a c e o u s s h a le 7 3 9. 5 5 C o a l # 0 b o t t o m 7 3 4. 2 2

Stresses Forces Acting on Rock at Depth V H2 H1 H1 H2 VR M T FORCES ACTING ON ROCK AT DEPTH V= Weight of rock above H1 and H2= Tectonic (Horizontal Stress) Vr= Reaction to weight of rock above

Stresses Primary mining redistributes the stresses in the ground we are mining IN SITU GROUND STRESSES STRESSES AROUND UNDERGROUND OPENING ROADWAY EXCAVATION

Stresses Redistribution of stresses around underground workings

Stresses ROOF PILLAR M T FLOOR

Stresses ROOF PILLAR SPLIT PILLAR M T FLOOR

Stresses

Stresses Secondary mining alters those stresses further M T Redistribution of stresses after PE is proportional to the magnitude of the change that mining creates

Goaf Conditions

Roof Lithology ROOF STRATA ASSESSMENT ROOF STRATA ASSESSMENT CLIENT: Joy Mining Machinery SITE: Zero Seam, Aujan Hill, Chirimiri Colliery LOGGED BY: L.Meyer - CORE A CLIENT: Joy Mining Machinery DATE CORED: 13 th February 2002 DRILLING: SITE: Zero Seam, Aujan Hill, Chirimiri Colliery LOGGED BY: L.Meyer - CORE B DATE CORED: 19 th February 2002 DRILLING: MATERIAL PROPERTIES U.C.S. Modulus U.C.S. / Sample (MPa) (GPa) Modulus Number THICK. HGHT. (m) (m) 5.00 5 0.67 4.30 0.30 0.5 4.00 4 3.95 0.15 3.80 0.60 RQD (%) 38 90 LITHOLOGICAL AND FRACTURE LOG FRACTURE LOG LOG DESCRIPTION COAL GREY MUDSTONE MUDSTONE COAL DARK GREY MUDSTONE WITH PLANT MATERIAL MATERIAL PROPERTIES LITHOLOGICAL AND FRACTURE LOG U.C.S. Modulus U.C.S. / Sample THICK. HGHT. RQD FRACTURE (MPa) (GPa) Modulus Number (m) (m) (%) LOG LOG DESCRIPTION 5m TOP OF CORE 5.00 5 COAL 1.0 30 4.00 4 COAL/MUDSTONE 0.80 3.20 0.40 3 2.80 0.70 1.25 2.10 2 0 0 WEAK MUDSTONE COAL LIGHT GREY MUDSTONE 1.15 1.25 3.20 3 2.05 2 COAL GREY MUDSTONE M T 85 1 0.85 0 0 Low Friction Plane Bedding Plane Parting COAL Oblique Fracture Broken Core 0.80 1 0.80 0 Low Friction Plane Bedding Plane Parting COAL Oblique Fracture Broken Core

A 5 0 3 4 B 2 1 0

Lithology C H A - 6 Elevation 781.36 23 Level, 2 R ise E 7 5. 0 0 0 7 5. 0 0 0 781.36 S ludge 760.86 Sandstone (M GD ) 741.36 S h a le 736.14 C oal #0 top 734.68 727.61 S andstone (C GD ) 734.06 714.21 C oal #1 733.86 C oal #0 m id 712.51 Sandstone (C GD ) 732.33 Shale C oal #0 bottom 691.86 727.61 C H A - 5 E le v a t io n 8 0 0. 1 0 1 5 L e v e l, 3 R is e E 7 5. 0 0 0 7 5. 0 0 0 769.6 733.9 731.9 800.10 Sludge 775.1 776.1 C oal 774.6 S h a le Sludge 741.6 C oal #0 bottom Sandstone (M GD ) 735.05 Shale 732.3 C oal #0 top 726.0 731.1 C arbonaceous shale C oal #0 m id S hale S andstone 667.0 7 5. 0 0 0 7 5. 0 0 0 C H A - 7 Elevation 791.26 8 Level, 5 R ise W 791.26 Sandstone 749.26 S hale 732.46 722.56 C oal #1 local 720.66 Shale 720.31 Sandstone (M GD ) Sandstone (M GD ) 742.43 Shale 741.15 C oal #0 top 739.76 C arbonaceous shale 739.66 C oal #0 m id Shale 738.50 C oal #0 bottom 736.41 660.51 661.26 657.06 Sandstone (M GD ) 655.51 637.76 C oal seam local S hale C oal #1 C H A - 8 E le v a t io n 8 7 5. 2 2 2 le v e l, 1 R is e W 875.22 S andstone M T 803.72 806.72 C la y 802.72 S hale 787.22 S andstone 781.72 S hale S andstone C o a l # 1 lo c a l 734.22 720.42 718.54 706.72 S andstone (FG D) S andstone 747.72 C la y 745.22 742.47 C a r b o n a c e o u s s h a le C o a l # 0 t o p 741.4 Carbonaceous shale 739.55 Coal #0 bottom 734.22

Goaf loading cycles σ First goaf Load if overburden doesn t fail Peaks caused by overhangs and/or goaf hanging up Load before pillar failure Face advance -->

Pillar Dimensions

Pillar Dimensions 33.0 10.5 6.6 13.7 5.5 6.6 33.0 27.5 5.5 M T

Pillar Split Dimensions 5.5 8.0 13.5 6.0 8.0 14.0

Depillaring Dimensions 10.0 5.0 6.6 8.0 3.0 18.7 2.0 2.3 8.8

Extraction Sequence

Pillar Extraction Sequence 1

Pillar Extraction Sequence 2

Pillar Extraction Sequence 3

Pillar Extraction Sequence 4

Pillar Extraction Sequence 5

Pillar Extraction Sequence 6

Pillar Extraction Sequence 7

Pillar Extraction Sequence 8

Pillar Extraction Sequence 9

Pillar Extraction Sequence 10

Pillar Extraction Sequence 11

Pillar Extraction Sequence 12

Pillar Extraction Sequence 13

Pillar Extraction Sequence 15

Pillar Extraction Sequence 16

Pillar Extraction Sequence 17

Pillar Extraction Sequence 18

Pillar Extraction Sequence 19

Pillar Extraction Sequence 20

Pillar Extraction Sequence 21

Pillar Extraction Sequence 22

Pillar Extraction Sequence 23

Pillar Extraction Sequence 24

Pillar Extraction Sequence 25

Pillar Extraction Sequence 26

Pillar Extraction Sequence 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Micro Environment

Components of the process Micro Environment (In seam) Cutting sequence Joints/slips/geological discontinuities Sidewalls Systematic support Goaf edge support Junctions/intersections Hazardous area / No-go area

Risks associated wit Depillaring Joints/slips Roof Intersections Sidewalls Goaf Air blasts All other risks associated with mechanised mining M T

Position of CM Operator

CM Operator s Position 1 M T

CM Operator s Position 2 M T

CM Operator s Position 3

CM Operator s Position 4 M T

CM Operator s Position 5 M T

CM Operator s Position 6

CM Operator s Position 7 M T

CM Operator/2 nd CM Operator Evaluate conditions at all times Stay under supported roof Be careful of sidewalls especially jointed/cleated sidewalls Be aware of shuttle car

Roofbolt Breakerlines Breakerline before goaf Breakerline after goaf Goaf Edge support

Goaf Edge Support Dimensions 0.5 0.8 1.6 1.6 1.0 0.8 25.5 1.3 14.0 0.8 5.0 8.0 M T 25.5

Roofbolt Breakerlines Roofbolt breakerline installed No breakerline installed

Timber Support M T Policemen sticks or Indicator props

Policemen

Policemen Not goaf edge support only indicator props Outer props should be placed before depillaring of fender starts Pillar outer edges most important Policemen inside split exposes more men to goaf Time consuming to cut props to correct length M T

Policemen M T DGMS Proposal

Discontinuities

Support of discontinuities M T

Roof Discontinuities

Ribside Discontinuity Support Roof Heading Discontinuity Cleating Floor

Ribside Discontinuities

Hazardous Area M T 1 Complete pillar line behind extraction line, demarcated by barricade

Nounauthorised personnel in hazardous area Everybody in hazardous area report first to supervisor or CM operator No loitering in hazardous area Nospectators or visitors Hazardous area

No-Go Area Goaf Line No-Go Area Hazardous Area

trata Condition Monitoring M T

trata Condition Monitoring 108 individual units of strata monitoring devices for first panel To provide information in terms of goaf, roof and support condition Information for DGMS for application of depillaring in 2 nd panel No hold-up in production, continuous extraction of pillar the most important

RMT Single Height, Rotary Telltale

TELL TALES ARE SAFETY DEVICES WHICH PROVIDE A CONTINUOUS VISUAL INDICATION OF THE LEVEL OF ROOF DEFORMATION THAT HAS TAKEN PLACE WITHIN THE MONITORED HEIGHT FOLLOWING INSTALLATION HE ROTARY DESIGN HAS BEEN DEVELOPED TO GIVE A RESOLUTION OF 1mm HIS ACCURACY IS IMPORTANT AT SITES WHERE ROOF DEFORMATION EVELS ARE GENERALLY LOW RMT

0 0 How a rotary tell tale works 1 2 REFERENCE REFERENCE No. No. 3 4 5 6 25 7 7 24 8 23 22 22 9 21 21 21 10 10 R M T 20 20 20 11 11 19 19 18 12 17 13 14 15 16 RMT

R M T ACTION LEVELS GREEN 0-5 mm YELLOW 5-10 mm RED 10 mm +

R M T ACTIONS GREEN YELLOW RED No action required, continue routine monitoring Install additional standard length reinforcement to increase density of support. Install sonic extensometer to identify type and location of deformation. To be coordinated by Bolting Engineer - RMT Restrict access. Consult Supervisor / Under Manager/ Strata Control Officer - RMT.

GOLDEN RULE IF YOU SEE ANY TELL TALE IN YELLOW SECTOR INFORM YOUR SUPERVISOR RMT

GOLDEN RULE IF YOU SEE ANY TELL TALE IN RED SECTOR WITHDRAW FROM AREA AND INFORM YOUR SUPERVISOR RMT

Golden rules for Micro Environment Evaluate conditions at all times Be awake/aware at all times Stay in the middle of roadways Stay away from sidewalls Stay away from intersections/junctions Stay away from Joints/slips Stay out of No-Go areas Minimize amount of people in hazardous areas Do not run, walk out swiftly M T

Golden rules for Macro Environment M T Evaluate conditions at all times Stay in sequence Keep a continuous rate of extraction Evaluate time to extract fender before commencement of depillaring Once a fender has been started it should be completed ASAP Do not go back to a snook or fender that has been standing for more than 2hrs