COUPLING AND COHERENCE ESTIMATES FROM SINGLE-FIRED CYLINDRICAL EXPLOSIONS

Implications for Using Single Hole Waveforms in Multi-Hole Simultations

B. StumpX. Yang

D.C. PearsonR. MartinJ. SmithV. Hsu

OVERVIEW

Single shot characterization (130-650 lbs)

Single shot characterization (5500-50000 lbs)

Superposition modeling

Identification of blasting anomalies

Single shot characterization (130-650 lbs)Experimental Layout

3002502001501005000

50

100

150

200

250

300

accelerometerblast

m

m

N

B1

B2

B3

B4

B5

1

2

3

45

6

78

test bench pit

charge depth

burden

charge length

explosive

stemming

Single shot characterization (130-650 lbs)Shot Sizes

Diameter = 0.31 m

backfill

ANFO

EMULSION

air deck

stemming

1

78 kg

2

296 kg

3

89 kg

4

197 kg

5

59 kg

6

89 kg

7

59 kg

8

296 kg

1

2

34

5

6

78

9

10

0Shots

Single shot characterization (130-650 lbs)

Single shot characterization (130-650 lbs)Waveforms

0 0.1 0.2 0.3 0.4 0.5 0.6 0.740

60

80

100

120

140

160

Time (sec)

Longitudinal

P wave S wave

Single shot characterization (130-650 lbs)Amplitudes

102

100

101

l

ll

l

l

ss

s

s

s

G

Shot 1

l Shot 2Shot 3Shot 4Shot 5Shot 6Shot 7

s Shot 8

Distance from shots to receivers (m)

Single shot characterization (130-650 lbs)Modeling - Source

a) Explosion SourceMueller-Murphy model

b) Vertical SpallOpening of horizontal crackUnloadingSlapdownPit Depth

c) Horizontal SpallOpening of vertical crackHorizontal slapdown in pit

Single shot characterization (130-650 lbs)Modeling - Propagation

Refraction Survey

0 20 40 60 80 1000

0.01

0.02

0.03

0.04

0.05

Sourcereceiver offset (m)

P wave

0 10 20 30 40 50 60 700

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

Sourcereceiver offset (m)

S wave

Table 2 Test site velocity model

thickness(m)

Vp(m/sec)

Vs(m/sec) (g/cm3)

Q p Q s

Top layer 3.1 500 250 1.7 3 1

Half space 2400 1000 2.0 35 8

Single shot characterization (130-650 lbs)Modeling - Synthetics

observation

synthetic

Single shot characterization (5500-50000 lbs)Local Data

Time (s)

Single shot characterization (5500-50000 lbs)Regional Data

10-1

10-1

100

-10

100

-10

200

-20400

-40100

0-100

0 10 20 30 40 50 60 70 80 90Time (s)

Single shot characterization (5500-50000 lbs)Correlation

14

6

7

Single Shots

0 10-10Time (s)

235

Cross-Correlation (with s5)

Single shot characterization (5500-50000 lbs)Coherence

0 2 4 6 8 10 12 14 16 18 20-0.2

0

0.2

0.4

0.6

0.8

1

1.2

S4-S3 30 m

S6-S3 350 m

S7-S3 3820 m

Frequency (Hz)

Single shot characterization (5500-50000 lbs)Source Scaling Data and Model

10 -1 10 0 10 1 10 210 -1

10 0

10 1

Frequency (Hz)

Spectral Ratios for S7 & S6 P and Lg Waves at Pinedale

P waves

Lg waves

10-1 100 101 10 210 -1

10 0

10 1

Spectral Ratios for S7 (50000 lb) & S6 (16000 lb)Using Mueller-Murphy Spherical Source Model

Frequency (Hz)

Single shot characterization (5500-50000 lbs)Regional Amplitudes

Single shot characterization (5500-50000 lbs)Data Visualization

Single shot characterization (5500-50000 lbs)Model Visualization

Superposition modeling

u 35 ms per hole in a row, u 200 ms between rowsu Total source durations > 4 s

Identification of blasting anomalies

Identification of blasting anomaliesWell performing shot

Identification of blasting anomaliesAnomaly 1- Observation

Identification of blasting anomaliesAnomaly 1- Model

Identification of blasting anomaliesAnomaly 2 - Data

CONCLUSIONS

Yield Scaling for Single-Fired shots

Source Model with Propagation Path Model can be used

Superposition provides means for estimating effects

Identification of blasting anomalies is possible