TSF EMBANKMENT DATA
VALIDATION
14TH OCTOBER, 2014

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)

SETTLEMENT OF THE TSF