Contents
1. INTRODUCTION
2. STATEMENT OF PROBLEM
3. DISCUSSION
4. CONCLUSION & RECOMMENDATIONS
INTRODUCTION
LO C AT I O N O F T H E T S F E M B A N K M E N T S
STATEMENT OF PROBLEM
• Concerns have been raised on the interpretation of the TSF embankment pins with respect to the survey monitoring data hence the need for survey to review the survey process.
• Validation of the survey data
STATEMENT OF PROBLEM
HOW THE SURVEY REPORT LOOKED LIKE BEFORE THE
REVIEW AND VALIDATION OF
SURVEY DATA
DISCUSSIONS
• Leveling is the approach use to monitor the elevations of the TSF embankments. • Total Station is also used for the position monitoring (N,E)
• Personal: Graduate Surveyors (Experience Surveyors)
• Equipment : Precised Levelled instrument (z) with an accuracy of
0.7mm in 1Km
• SOP: Known Control(Beacon)
Misclosure
Allowable Misclosure i.e. ±5√n where n is the number of instrument stations occupied
Questions
• Are the Beacons tested for stability before start of work?
• Is the misclosure within the allowable tolerance ?
• Is the level adjusted and apply to the new z’s?
Answers
POINT OF DEPARTURE TEST ON BEACONS
BEACON
EXISTING COORDINATES
NORTHING
EASTING
CURRENT COORDINATES
ELEVATION NORTHING
EASTING
RESIDUALS
ELEVATION
∆E
∆N
∆Z
TSF 1
183943.512
269961.1
183.196
183943.51
269961.099
183.199
0.002
0.002
-0.003
TSF 3
183960.073
269007.75
187.443
183960.069
269007.746
187.441
0.004
-0.001
0.002
TSF 4
182740.325
268970.27
187.153
182740.322
268970.271
187.149
0.003
0.002
0.004
TSF 6
182520.472
270022.29
186.305
182520.469
270022.286
186.304
0.003
0.003
0.001
No movement in vertical position (∆Z) of Beacons
Answers
Surveyor
Date
Start Row
End Row
Start
End
Misclose/m
No Stations
Adj Per Sta
Misclose/mm
Otoo
9/26/13 9:00
61
72
187.443
187.4464
-0.0034
10
-0.0003
-3.4
15.8
Otoo
9/26/13 11:00
73
85
186.323
186.3191
0.0039
11
0.0004
3.9
16.6
otoo
10/17/13 8:00
86
95
187.443
187.4395
0.0035
10
0.0003
3.5
15.8
Otoo
10/17/13 9:00
96
107
186.323
186.3200
0.003
9
0.0003
3
15.0
Otoo
11/15/13 0:00
108
198
183.196
183.2030
-0.007
13
-0.0005
-7
18.0
Otoo
11/15/13 11:30
215
321
186.323
186.3153
0.0077
11
0.0007
7.7
16.6
Otoo
12/13/13 0:00
322
334
187.443
187.4276
0.0154
11
0.0014
15.4
16.6
Otoo
12/13/13 11:00
335
346
186.323
186.3286
-0.0056
9
-0.0006
-5.6
15.0
Otoo
1/17/14 0:00
347
359
187.443
187.4431
-0.0001
11
0.0000
-0.1
16.6
Otoo
1/17/14 9:14
360
373
186.323
186.3224
0.0006
11
0.0001
0.6
16.6
Otoo
2/16/14 8:00
374
384
187.443
187.4463
-0.0033
11
-0.0003
-3.3
16.6
Otoo
3/22/14 8:00
397
410
187.443
187.4453
-0.0023
13
-0.0002
-2.3
18.0
Otoo
3/22/14 10:00
411
422
186.323
186.3204
0.0026
11
0.0002
2.6
16.6
Otoo
4/22/14 0:00
423
436
187.443
187.4415
0.0015
12
0.0001
1.5
17.3
Otoo
4/22/14 10:00
437
447
186.323
186.3178
0.0052
9
0.0006
5.2
15.0
CHECK MISCLOSURE (±5√n)
/mm
Answers
o movements in horizontal positions (∆N and ∆E) of TSF Embankmen
Answers
SP-05 VARIANCES OVER THE MONTHS SURVEYED
SETTLEMENT OF THE TSF EMBANKMENT AFTER THE
REVIEW OF SURVEY PROCEDURE
There has been a stable settlement in the embankment since we reviewed and validated the survey procedure in June
(after the yellow dashed line)
