pvk 17062011
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STRESS MAPPING FOR RE- ORIENTATION OF GALLERIES IN
PVK-5 Incl.
Dr.D.N.SHARMADy.General Manager(Geo)
Exploration Division / RG1
• In PVK mine, King Seam workings reached 400m depth.
• Thickness of the King Seam in the study area is about 6.50m with a gradient of 1 in 8.
• King seam was developed in the Top Section upto 116 Level, withSandstone as immediate roof.
• Since there is a problem with sever seepage of water along sandstone roof , an attempt was made to leave about 3.50m seam portion in the roof.
• In the changed working section, another problem of severe roof failures in Level galleries cropped out.
1. PROBLEMS IN KING SEAM
2. STRESS MAPPING IN QUEEN SEAM
With a similar problem in overlying Queen Seam workings that is beyond 110 Level at a depth of 350m, Stress mapping was carried out, during June 2004. The inferences of those studies were-
The Major Principal Stress axis inferred from most prominent Joint set (J1) is perpendicular to Level galleries are contributing for instability of level galleries.
Minor Principal Stress axis inferred from least prominent Joint set (J3) is parallel to level galleries.
Conversely, Dip galleries are stable as they are almost (with about 5 degrees) parallel to the Major Principal Stress axis.
Further, these findings were closely matching with that of Stress Orientation established earlier in the Queen Seam of adjacent VK-7 Shaft through similar Stress Mapping technique.
CONTOUR DIAGRAM OF JOINTS PLOTTED ON EQUAL AREA PROJECTION,LOWER HEMISPHERE,
QUEEN SEAM (100 JOINT POLES)
DIRECTION OF STRAIN ELLIPSOID DEVELOPED IN QUEEN SEAM
3. STRESS MAPPING IN KING SEAM
1. Stress mapping is carried out in the present study area in King Seam.2. The workings crossed 400 m. depth line and approaching the F16 Fault
(throw 20m) in the dip side property. 3. The details of structural features mapped are as follows -
SL.NO STRUCTURAL FEATURE NO.OF READINGS. MEAN TREND
1 FACE CLEAT140
N550E
2 BUTT CLEAT N350W
3 MOST PROMINENT SLIPS40
N450 E
4 LEAST PROMINENT SLIPS N650E
5 MOST PROMINENT JOINTS27
N550E
6 LEAST PROMINENT JOINTS N650E
3. STRESS MAPPING IN KING SEAMContd…
4. The causative factors of unstable roof conditions are due to :
• The most prominent Slips S1 aligned to the greatest principal stress direction (N450E) is responsible for the roof instability confined to level galleries.
• Roof strata consists of thin layers and leading to failure in level galleries with an indication of "Gutter roof". Trend of the "Gutter roof" ,largely helped to confirm the orientation of principal stress in the study area.
• As workings are enveloped by Faults, sympathetic slips developedand contributed for unstable roof conditions.
• These findings are closely matching with that of Stress Orientation established in the overlying Queen Seam.
FACE AND BUTT CLEAT
SLIP IN THE PILLAR SHOWING DISPLACEMENT OF BANDS
J1 JOINT EXPOSED IN THE FLOOR
4. ROCK MASS RATING (RMR)RMR classified the roof of working section of King Seam (Bottom Section) as "FAIR“ with a rating of 41, where 40 is border of “Poor”and “Fair” rock.
“ROOF GUTTERING” IN THE CENTER OF LEVEL GALLERY BEFORE RE-ORIENTATION
5. NUMERICAL MODELLING BY CIMFRNumerical modelling was taken up by CIMFR and the following conclusions and recommendations are made:
1. The magnitude of major and minor in situ horizontal stresses in King seam in the study area are found to be 7.15 Mpa and 3.68 Mparespectively.
2. The direction of the major in situ horizontal stress is found to be along N 450 E , which is almost perpendicular to the level galleries.
3. Keeping the above directions and magnitude of in situ horizontal stresses in view, level gallery can be driven along N 850 E toE 50 S (with a stress point of view).
6. ORIENTATION OF GALLERIES REFERENCE TO PRINCIPAL STRESS
N
N 7
° E
N 1
0°
E
N 2
4° E
N 55° E
N 69° E
N 62° W
N 47° W
F5R
E-O
RIE
NTE
D-1
DG
F18
F10 & J1
& FC
F9
F16
RE-ORIENTED-1.LG
S1N 4
5° E
N 65° E
S2 & J2
N 35° WBC
N 73° E
ORIGINAL DG
N 24° W
OR
IGIN
AL LG
INDEX
N 45° W
1
N5
°WR
E-O
RIE
NT
ED-2
DG
N85°ERE-ORIENTED-2. LG
S1 MOST PROMINENT SLIP
J1 MOST PROMINENT JOINTS2- NEXT PROMINENT SLIP
J2 NEXT PROMINENT JOINT
FC- FACE CLEATBC-BUTT CLEAT
1- MAJOR PRINCIPAL STRESS 3- MINOR PRINCIPAL STRESS RE-ORIENTED-1 DIP GALLERY
RE-ORIENTED-1.LEVEL GALLERYORIGINAL DIP GALLERYORIGINAL LEVEL GALLERY
RE-ORIENTED-2 DIP GALLERYRE-ORIENTED-2. LAVEL GALLERY
EW
3
N/55
N/49
N/46
N/48
N/51
N/46A
N/50
N/29
1 IN
5.1
9
TS T
O K
S
108L96L
15D
11D
7D
4D
1D
85L
90L
533.50
558.2
0
527.50
543.45
552.06
549.55
569.30
569.
60
N/30
N/47
85L
82L
MIDM
WD
88L
TO KS/TS1 IN 10
LEVE
L D
RIFT
LEVE
L DR
IFT
LEV
EL D
RIFT
1 IN
6
1 IN
10
1 IN
10
1 IN
10 1 IN 10
1 IN 10
1 IN 6.7
1 IN
10
2.4M
0.5M
3.2M 0.7M 0.
3M0.2
M
1.2M502.8
7
0.8M
1.3M
23D
4M
3.8M
1.2M
25D
27D
30D
92L
578.
47
F.K.S...... 447.69(5.20)
557.
40
485.36
535.
98
565.
50
20D
20D
22D
97L
95L
L.T. LINE
HAULER ROOMSURFACE150 HP
816.13
816.03B.M...816.54 M
OFFICE
No 5B INCLINE
11D
7D
TO KS/TS1 IN 10
TO KS/TS
1 IN 10
TO KS/TS
1 IN 10
1 IN
4 1
IN 5
M
ID
MW
D
5B AIR SHAFT
110L
25D
23D
21D
20D
1
IN
5.1
9
TS T
O KS
512.
490
DIA: 6.5M
1.2M
3.2M
3
2A
2
33 K.V. TRANSM
ISSION LINE
60m B
ARRIER
60m BAR RIER
60m BARRIER
60m
BAR
RIE
R
1 .20M3.20M
501.
595
0.60M
482.
49
487.
44
483.
20
508.
08
495.
53
494.
44
DEPTH :292M
PVK SHAFT
F10
F10
D/H
16D
12D
112L BELT LEVEL
487.
04
10D9D
S/22
472.2
9
0.40.250.350.1
0.22.0
0.1M0.25M
471.7
4473.0
8
8D
472.6
4
800.34
803.06
805.16
810.05
T E L L A
V A G U
807.68 HFL
803.72
805.00 HFL
HFL
WIT
H I
N TH
E N
ALLA
H
T E L L A V A G U
796.60
797.27
798.
05
DIVERTED
6D
4D
2D
0R
115L
482.5
2
488.0
7
479.6
9 488.2
8
492.6
4
464.0
85
462.9
4
462.4
0
458.7
7
500.6
86
UG B.H. TO K.S.
N82°W
N8°E
S5°E
S85°
W
N0 200
43D
45D
116CXCUT
412.533
419.193
404.653
400.388
398.573
415.898
533
.339
536.
670
539
.870 543
.450 546.
280
543.
53
537
.45 540
.57
530.
879
534
.18 53
7.37 54
0.5
253
4.00
530.
83
528
.26
5D
3D
552.
03 555
.10
551.
65
550
.44
548
.34
546
.035
49.1
2
542
.67 544
.78 546.
92
554
.30
540
.62
538.
53
535.
85
532
.0
548.
42
544.
86
422.05426.84
420.55
413.39415.19
409.25
404.69
426.55
JH
GH
GH
47D
49D
430.835
424.335
418.505
408.265
420.035
428.27
558
.55 56
0.35
556
.85 55
8.8
4
554.
17
549.
535
552.
38
544.
145
542
.42
536
.285
538.
825
38D
521
.984
12D
9D
517
.53
4
519.
614
510
.67
451
6.5
79
513.
749
405.596
1.8m
526
.869
524
.914
518.
859
424.11
403.156
410.266
533
.339
523.
924
524.
984
7D
40D
38D
116BXCUT
GH
B.H. No..A/326F.K.S...... 541.60(5.35)
DEPTH....310.00
28D
GH
GH
GH
506
.53
504.
38
488.
75
473.
67
512.8
38
509.5
88513
.043
524.3
18
519.0
8852
2.63
511.6
56
504.9
36
502
.09
505
.89
9
497
.899
494
.804
483.
759
BELT ROAD
434.
00
419.
61
396.
96
401.
42
396.
54
405.
72
394.0
394.36
391.43
489.2
3
481.0
4
490 .59
466.7
5
457.2
6
454.6
1
475.9
2
22D
3.5m
410.
41
418.
33
393.
34
395.
87
3.5m
4.5m
4.5m
494.8
8495.5
3
24D
26D
23D24D
26D
28D
30D
32D
34D
36D
GH
452.
72459
.66
457
.95
458.
291.6
2
0.70.8 1.20.6
0.4
0.8
0.7
0.6
22
UG B.H. TO K.S.
501.3
2
494.9
9
471.
03
469
.04
467.
46
452.
21
107L
488.41
0.8
0.80.7
0 .7
441.
9743
5.94
431.
69
424.
80
420.
23
JHw
96L
0.6
0.4
B.H. No..A/324S.L.... .....802.21
DEPTH....365.00DIA.. ......10CM
F.K.S...... 444.71(7.70)
484
.50
478
.48
487
.26
461.
73
460.
41
458.
0544
9.47
506.53
494.6
6
6.5m
PANEL No.S-21
1.4m
1.4m
0.5m
0.5m
0.2M
0.3M
0.3M
0.45M
12D
16DN 18D
20D
119L
15D
16DS
BELT LEVEL
BELT DIP
BELT
DIP
407.
29
436.
28
403.95408.18
415.50
412.01
1m
120L 120L
120L
22D
GH
GH
GH
GHGH
GH
HAULAGE DIP
HAU
LAGE
DIP
394.59
399.34
404.46
397.7 397.69
403.
48
404.
51
413.
67
425.
0943
1.97
437.
97
447.
48
400.
5
403.
5340
0.92
122L
GH
GH
122L
16BD 1.6m
2m
1.6m
16DN16AD
18D19D
94L
91L
5D
3D
1D
MID
122L123L
397.36
395.55
392.38
400.
47
403.
79
410.
51
1m
1m
1.6m
D/H
E/HD/H
13D
EH
END LESS HAULAGE
END LESS HAULAGEJ/H
123L
392.62
2.5m
394.
18
400.
47
395.
68
408.
51 410.
23
417.
7142
3.33
428.
35
474.6
847
8.52
463.1
0463.35
449.2
3
439.20
527.47
474.
76
465.
37
3
2A
2
3
2A
2
B.H. No..A/342
FKS-382.10
B O
U N
D A
R Y
3
2A
2
FKS-....429.39
B.H. No..A/306
P BORE HOLEDEPTH....240DIA........10CM
B.H. No. .A/320
DEPTH....310.00
F.K.S......516.23(5.35)
B.H. No..A/323
DEPTH.. ..367.00
F .K.S......449.25(6.80)
B.H. No..A/286
DEPTH..365.93
F.K.S.... 448.68(6.86)
B.H. No.. A/285
DEPTH....407.55
F.K.S...... 403.80(5.45)
B.H. No..KSB-7
DEPTH....431.92
F.K.S......409.61(6. 05)
B.H. No.. A/311A
DEPTH....375.00
B.H. No.. A/316
DEPTH....435.00
F.K.S......383.44(5.60)
B.H. No..A/115DEPTH....396.24
F.K.S......520.65(5.37)
B.H. No. .KSB-5DEPTH....339.38
B.H. No.. A/119DEPTH....262.1
B.H. No..KSB-14S.L.... .....804.07DEPTH....153MDIA.. ......10CM
B.H. No..A/319DEPTH....236
B.H. No..A/338DEPTH....216.50
B.H. No..A/337DEPTH....216.50
B.H. No..A/336DEPTH.... 213.00
B.H. No.. A\174
B.H. No.. A\178
B.H. No.. A\175
DEPTH....159.50
B.H. No.. A\157
DEPTH....161.85
DIA...... .....15CM
DEPTH....115.06
NO 1 ... 727.44 (19.58)S.L........ ....798.84
DIA...........15CM
DEPTH....65.68
NO 1SEAM ...780.210 (13.72)S.L.. ..........803.070
B.H. No. . A\183 DEPTH....56.80
B.H. No.. A\118 DEPTH.... 169.840
B.H. No.. A\185 DEPTH....53.03
B.H. No.. A/313
DEPTH.... 420.00
F.K.S......391.85(5.90)
B.H. No..A/350 (MPBX)DEPTH....285.00
B.H. No..A/340
462.3
9
447.36
439.
57
442.98
454.26
525.55
430.
944
441.
12
429.12434.183
447.9
7
453.6
4
3M
2M
0.8M
115L
117L
115L
117L
419.07
417.23
422.
71
426.
23
454.
9244
3.60
434.
68
416.
36
119L
417.
23
412.
25
1.4m
1.2m0.4M
0.4 1m
1.4m
1.4m
0.5m
0.65m
0.6m
0.8m
562
.13 56
3.38
559.
72
539.
48 541
.26
563.
658
561
.313
565.
412
567.
242
567
.102
562.
972
558
.625
554
.563
549
.663
547
.2285
50.2
9855
5.50
3
570
.53
7
566
.498
545.
818
113L
423.031
431.351
427.746
421.036424.486
416.911419.021
PANEL STD. ON 20-05-11
STABLE ROOF IN THE LEVEL GALLERY AFTER RE ORIENTATION
7. SUMMARY AND CONCLUSIONS
1. PHYSICAL MAPPING LARGELY HELPED TO DERIVE STRESS ORIENTATION IN THE STUDY AREA TO BE N450E.
2. THE DATA IS VALIDATED WITH THAT OF OVERLYING QUEEN SEAM AS WELL AS ADJACENT BLOCK i.e. VK-7 SHAFT.
3. FURTHER IT IS VALIDATED WITH NUMERICAL MODELLING DATA. 4. FINDINGS OF ALL THE ABOVE STUDIES ARE IN GOOD
AGREEMENT WITH EACH OTHER.5. BASED ON THE RECOMMANDATIONS (to drive Level Galleries in
N850E) OF ABOVE STUDIES, STABLE ROOF CONDITIONS COULD BE ESTABLISHED.
******
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