14

TABLE A~3. - Delay times for manufacturer A's coal mine delay detonators—-
third test series, arranged in ascending order and by designated nominal
delay, milliseconds

DP 1, DP 2, DP 3, DP 4, DP 5, DP 6, DP 7, DP 8, DP 9,
25-ms 100-ms 175-ms 250-ms 300-ms | 350-ms 400-ms 450-ms 500-ms
delay, delay, delay, delay, delay, delay, delay, delay, delay,
key key key key key key key key key
C-2552A | C-2552B C-2552C C-2552D | C-2552E | C-2552F C-2552G | C-2552H | C-25521
18.8 100.8 177.2 244.0 271.5 347.0 382.5 446.5 452.5
19.0 101.0 177.4 245.6 277.5 350.0 387.0 451.5 466.5
19.6 101.2 178.6 246.4 279.0 356.5 389.0 455.0 467.0
19.8 102.4 179.6 248.0 281.5 358.5 390.5 456.0 479.0
21.8 102.6 181.4 250.4 286.0 359.0 396.0 460.5 483.5
22.4 102.6 181.6 250.6 286.2 359.0 397.0 461.5 487.0
22.8 102.6 182.2 251.6 287.5 360.5 397.0 462.0 493.0
23.2 103.0 182.6 251.8 289.5 362.0 397.5 464.5 494.5
23.8 103.4 182.8 253.8 290.6 362.5 398.5 465.5 495.0
24.2 103.4 183.4 253.8 291.0 363.0 399.5 465.5 497.5
24.8 103.4 183.8 255.8 291.0 363.0 401.0 466.0 498.0
25.8 104.0 186.4 257.0 291.5 363.5 401.0 466.5 502.0
27.8 104.4 186.6 257.6 297.0 366.0 402.0 468.0 505.0
28.0 104.6 186.8 258.2 299.0 366.5 403.5 469.5 510.0
28.4 104.8 187.2 261.0 302.5 367.0 407.0 471.0 511.0
29.6 106.8 188.0 261.2 305.5 367.5 410.5 475.0 512.0
29.8 107.6 188.6 262.2 307.5 371.5 411.5 476.0 517.0
30.2 107.8 189.0 264.8 309.5 372.5 413.5 478.5 525.5
30.2 109.0 189.6 265.4 317.0 375.0 417.5 484.5 529.0
32.0 110.0 192.0 267.4 319.0 375.5 423.0 499.5 530.0

DP Delay period.


TABLE 3. - Summary of detonator delay measurement--manufacturer C

Delay values, ms Overlap
Delay Nominal] Average] Low} High Std. 100 o| (T,-T,) | probability, | Winzer
period (T,) (T,) (T.) | (T,) | dev. T, o pet index
(o)
FIRST TEST SERIES, KEYS C-2353 AND C-2375
25 23.5 17.4] 44.4] 5.7 24.26) 4.74
100 105.1 93.0] 117.4] 7.1 6.76] 3.44 ea fee
175 185.9 175.0 | 196.6 | 6.3 3.39] 3.43 New 4.86
250 248.3 228.4 | 268.6 | 11.2 4.51] 3.59 New. 4.64
300 319.2 299.5 | 338.5 | 10.4 3.26 | 3.75 0 67 2.90
350 365.9 349.5 | 394.5 | 12.3 3.36 | 3.62 11.26 1.21
400 399.1 371.5 | 448.0 | 24.6 6.16] 3.11 1.24 204
450 460.2 439.0 | 484.0 | 11.9 2.59] 3.78 °03 2.95
500 519.9 477.0 | 551.5 | 16.4 3.15 | 4.54 . .
SECOND TEST SERIES, KEY C-2473
25 22.77 19.4] 29.8] 2.56 | 11.24] 4.06
100 |107.46 | 96.8/119.4] 5.60 | 5.21] 4.04 ea oat
175 186.91 {171.8 | 210.4 | 10.53 5.63] 3.67 New. 6.90
250 288.19 | 266.6 | 312.0 | 10.22 3.55] 4.44 2 re 1.97
300 315.33 | 292.5 | 335.5 | 9.28 2.94] 4.63 Ne 3.22
350 374.20 | 344.0 | 412.0 | 15.77 4.21} 4.31 5 55 1.61
400 426.28 | 370.5 | 474.5 | 28.14 6.60| 3.70 5.08 1.64
450 473.75 |457.0 | 488.5 | 7.02 1.48] 4.49 “04 2.93
500 541.38 | 503.0 | 580.0 | 21.99 4.06 | 3.50 . .
THIRD TEST SERIES, KEY C-2586
25 24.05 20.2 | 28.4] 2.40 9.99] 3.41 Ne 9.24
100 111.38 95.2 | 126.8 | 9.14 8.21] 3.46 New. 6.31
175 187,05 | 173.4 | 204.8 | 7.77 4.16} 4.04 New. 5.11
250 249,52 | 232.8 | 274.6 | 9.43 3.78 | 4.43 New. 3.00
300 323.83 | 300.0 | 344.0 | 11.50 3.55] 3.83 6 5 1.52
350 357.63 | 323.3 | 389.0 | 19.05 5.33] 3.44 3.92 1.76
400 403.43 | 373.0 | 442.0 | 17.77 4.41] 3.88 1.56 214
450 457.80 |431.0 | 502.5 | 18.10 3.95] 3.95 2229 1.99
500 508.73 | 469.5 | 546.5 | 18.04 3.55] 4.27 . .

Neg. Negligible.


18

TABLE C-3. - Delay times for manufacturer C's coal mine delay detonators--
third test series, arranged in ascending order and by designated nominal
delay, milliseconds

DP il, DP 2, DP 3, DP 4, DP 5, DP 6, DP 7, DP 8, DP 9,
25-ms | 100-ms 175-ms 250-ms 300-ms 350-ms 400-ms | 450-ms 500-ms
delay, delay, delay, delay, delay, delay, delay, delay, delay,
key key key key key key key key key
C-2586A | C-2586B | C-2586C | C-2586D | C-2586E | C-2586F | C-2586G| C-2586H | C-2586I
20.2 95.2 173.4 232.8 300.0 323.5 373.0 431.0 469.5
20.4 101.0 175.0 241.2 309.0 326.5 375.0 434.5 483.5
21.6 102.6 175.8 241.6 310.5 338.5 383.0 435.5 486.0
21.6 103.2 176.2 241.8 310.5 342.0 386.5 438.5 497.5
22.0 103.8 182.8 242.0 311.0 342.5 388.0 442.5 499.5
22.6 104.6 183.9 242.2 319.0 344.0 393.0 446.5 503.5
22.6 105.2 185.0 243.8 319.0 345.5 396.0 447.5 504.0
22.8 105.2 186.8 244.6 322.0 346.5 400.5 449.0 504.5
23.4 107.0 187.0 245.8 325.0 349.0 401.0 449.5 505.0
24.0 110.8 187.6 248.8 325.0 353.5 404.0 460.0 505.5
24.0 112.0 188.4 249.0 325.5 360.5 404.0 461.0 505.5
24.6 112.6 189.2 249.4 325.5 363.0 404.0 461.5 511.0
24.8 112.6 189.6 250.6 326.5 368.0 404.5 462.0 512.0
24.8 113.0 189.8 253.0 328.5 372.5 410.5 464.5 515.0
25.2 118.6 190.2 253.6 328.5 374.5 415.0 467.0 516.5
26.2 121.6 192.8 256.2 333.5 376.5 416.5 472.5 517.0
26.2 123.0 193.0 257.4 336.0 377.0 421.0 476.0 525.5
27.6 124.2 193.2 259.0 338.5 378.5 422.5 477.0 528.0
28.0 124.6 196.4 263.0 339.0 381.5 428.5 477.5 539.0
28.4 126.8 204.8 274.6 344.0 389.0 442.0 502.5 546.5

DP Delay period.

#U.S. GPO: 1985-505-019/20,050

IN T.«BU.OF MINES,PGH.,PA. 27564


CONTENTS

ADSEIACE cece eeeee cece cece rece reeecseeesensseseees
Introduction. ...eeeeeeeees
Experimental technique.
Results and discussion.. Sec e cece eee ecencceee dec e eee eeeeeeeeee
Appendix A.--Delay times for manufacturer A's coal mine delay detonators.......
Appendix B.--Delay times for manufacturer B's coal mine delay detonators.......
Appendix C.--Delay times for manufacturer C's coal mine delay detonators.......

ILLUSTRATIONS

1. Schematic diagram of experimental setup used for detonator delay

MCASULEMENE sss eseeeeeeseceseececeees
2. Typical firing current profile.....
3. Typical firing voltage signature.....
4. Delay times for manufacturer A's detonators.......
5. Delay times for manufacturer B's detonators.......
6. Delay times for manufacturer C's detonators.......

TABLES

1. Summary of detonator delay measurement--manufacturer A....

2. Summary of detonator delay measurement--manufacturer B....

3. Summary of detonator delay measurement—-manufacturer C.csececccceececeees
A-l. Delay times for manufacturer A's coal mine delay detonators--first test

SETTLES ceceercccevrecccrccevcccevcsecuvssesecseeerssesesssesesseeesssenes

A-2. Delay times for manufacturer A's coal mine delay detonators--second test

SETLES Lecce eerereeeverercrcrncrereesssseseseserseeesscsercsssececsesenes

A-3. Delay times for manufacturer A's coal mine delay detonators--third test

SCTLCS cc eecececccccrcccncncccsceeerseeseseeeeeseeeeeseeeeeeeseesseseeeee

B-l. Delay times for manufacturer B's coal mine delay detonators—
serieS..ceeeee ee eeee
B-2. Delay times for manufacturer B's coal mine delay detonators--second

TESE SCTICS rr ee reeerercccncncvcrnsncncneseeesssesseeeeees

B-3. Delay times for manufacturer B's coal mine delay detonators—-third test
SETLES sc ecerscccerecccevccceseressene reese esses sees seseessssseesseseees

C-1. Delay times for manufacturer C's coal mine delay detonators--first test
SCTLES. cece eee c cece cece cece rcce cn cnse cece erence ssessseseseseneenseees

C-2. Delay times for manufacturer C's coal mine delay detonators--second test
series....... Seem cece eee eeeeeerececesenevene

C-3. Delay times for manufacturer C's coal mine delay detonators—-third test

SOLTLES sc eccecccsecesccccvevcccevvces

ona

13

13

14

15

15

16

17

17

18


APPENDIX B.--DELAY TIMES FOR MANUFACTURER B'S COAL MINE DELAY DETONATORS

15

TABLE B-1. - Delay times for manufacturer B's coal mine delay detonators--first test
series, arranged in ascending order and by designated nominal delay, milliseconds

DP 1, DP 2, DP 3, DP 4, DP 5, DP 6, DP 7,
25-ms 100-ms 170-ms 240-ms 320-ms 400-ms 500-ms
delay, delay, delay, delay, delay, delay, delay,
key C-2372A| key C-2372B | key C-2372C | key C-2372D| key C-2361A | key C-2361B | key C-2361C
10.6 31.0 137.6 242.0 296.5 379.5 492.0
11.6 42.2 138.2 242.5 302.0 387.0 498.5
12.0 44.8 140.0 243.0 308.5 392.0 501.0
12.0 49.5 140.8 243.5 313.0 392.0 506.5
12.6 56.0 143.8 244.0 315.0 393.0 510.5
12.6 57.5 144.4 244.4 315.5 399.0 513.0
13.0 58.5 148.8 244.5 316.0 399.0 514.5
13.4 59.2 149.4 249.0 316.5 399.5 516.0
14.2 59.5 149.4 250.0 317.0 400.0 516.5
14.4 60.2 151.0 250.6 318.0 401.0 517.0
14.4 65.2 153.0 253.4 320.0 404.0 517.5
14.6 65.6 153.4 257.0 322.5 404.5 519.5
14.8 66.4 154.6 258.4 330.0 405.0 521.0
14.8 66.5 156.0 259.2 332.0 4lL.5 525.5
15.0 67.2 157.2 259.8 335.0 422.5 525.5
15.4 69.0 163.2 262.0 342.5 422.5 526.0
15.4 75.0 163.2 263.0 343.0 423.5 539.0
16.0 78.5 169.2 266.5 351.5 424.0 540.5
17.2 80.0 174.4 270.5 352.0 433.5 541.0
18.8 82.0 174.6 271.6 356.0 442.5 543.0

DP Delay period.

TABLE B-2. - Delay times for manufacturer B's coal mine delay detonators--second test
series, arranged in ascending order and by designated nominal delay, milliseconds

DP i, DP 2, DP 3, DP 4, DP 5, DP 5-1/2, DP 6, | DP 6-1/2, DP 7,
25-ms 100-ms 170-ms 240-ms 300-ms 350-ms 400-ms 450-ms 500-ms
delay, delay, delay, delay, delay, delay, delay, delay, delay,
key key key key key key key key key
C-2470A | C-2470B | C-2470C | C-2470D | C-2470E C-2475A C-2470F | C-2475B C-24706
11.6 65.4 151.2 238.8 300.0 322.0 378.0 453.0 470.0
16.0 76.4 153.6 238.8 304.5 325.0 384.0 455.5 473.5
16.6 80.4 158.0 239.8 305.0 333.5 386.0 457.5 479.0
17.0 82.2 162.6 241.0 315.5 336.5 389.5 470.5 490.0
18.6 84.8 165.0 243.4 319.0 338.0 390.0 471.5 492.0
18.8 88.4 166.6 245.6 321.0 339.0 391.5 473.5 495.5
19.4 88.8 167.0 246.0 324.0 341.0 392.0 473.5 497.0
19.8 89.2 167.8 248.2 324.5 344.0 397.5 474.5 497.0
21.0 90.8 168.0 252.0 328.5 344.5 399.5 475.5 497.5
22.0 91.8 170.0 254.4 328.5 344.5 400.5 479.5 497.5
22.2 92.4 174.0 256.2 329.0 347.5 403.0 483.0 498.0
22.4 93.6 174.8 257.4 331.0 348.5 406.5 483.5 505.0
22.4 95.2 175.6 259.0 331.5 351.5 411.5 486.5 505.5
22.6 95.4 176.0 263.8 331.5 354.5 415.5 488.5 508.0
22.8 96.6 177.8 266.0 338.5 354.5 417.5 490.0 510.5
23.6 97.8 179.6 268.2 339.0 358.0 419.0 491.0 514.5
24.6 98.2 179.8 270.2 339.5 361.0 422.0 494.0 515.0
25.6 98.8 183.4 271.2 346.5 361.5 422.5 494.5 515.5
25.8 99.4 187.4 272.8 348.5 362.0 423.0 509.5 523.0
31.2 102.0 196.8 274.6 360.5 373.0 425.0 511.5 530.0

DP Delay period.


17

APPENDIX C,.--DELAY TIMES FOR MANUFACTURER C'S COAL MINE DELAY DETONATORS

TABLE C-1. - Delay times for manufacturer C's coal mine delay detonators--first test
series, arranged in ascending order and by designated nominal delay, millseconds

DP I, DP 2, DP-3, DP-4, DP 5, DP 6, DP-7, DP 8, DP 9,
25-ms 100-ms 175-ms 250-ms 300-ms 350-ms 400-ms 450-ms 500-ms
delay, delay, delay, delay, delay delay, delay, delay, delay,
key key key key key key key key key
C-2375A_| C-2375B | C-2375C C-2375D C-2353A | C-2353B | C-2353C | C-2353D C-2353E
17.4 93.0 175.0 228.4 299.5 349.5 371.5 439.0 477.0
18.2 93.0 176.2 230.2 304.0 350.0 373.0 442.0 502.5
19.0 94.2 177.6 232.2 308.5 350.5 374.0 447.0 503.0
20.2 99.4 179.2 239.6 309.0 351.5 376.5 448.0 505.5
20.8 100.0 180.2 240.6 311.5 353.5 379.5 451.0 510.5
20.8 100.2 182.8 242.6 312.5 356.0 380.0 455.5 512.0
21.0 101.2 183.6 244.4 313.0 361.0 384.5 456.0 513.0
21.4 104.4 184.0 245.0 313.5 363.0 385.0 457.0 515.5
21.8 105.2 184.6 246.4 316.5 363.0 385.5 457.5 517.5
22.2 106.4 184.6 246.8 317.0 365.5 386.5 460.0 518.5
22.6 107.0 186.2 248.6 321.0 366.5 389.5 460.0 519.0
22.8 107.0 187.8 249.2 322.0 369.0 392.0 460.0 523.5
23.0 107.4 188.2 250.6 323.5 370.0 403.0 461.0 526.0
23.6 108.0 189.6 252.2 324.5 371.0 408.0 463.5 529.0
24.0 108.6 190.6 252.4 326.0 372.5 414.5 464.5 531.5
24.4 108.6 191.6 259.4 328.0 373.0 429.0 473.0 533.5
25.0 111.2 192.0 260.6 329.0 373.0 433.0 474.0 534.5
28.8 113.2 192.4 263.2 330.5 377.5 433.5 475.0 536.5
28.8 117.0 195.4 264.8 335.5 388.0 435.5 476.5 537.0
44.4 117.4 196.6 268.6 338.5 394.0 448.0 484.0 551.5
DP Delay period.
TABLE C-2. - Delay times for manufacturer C's coal mine delay detonators—-second test
series, arranged in ascending order and by designated nominal delay, milliseconds
DP 1, DP 2, DP 3, DP 4, DP 5, DP 6, DP 7, DP 8, DP 9,
25-ms 100-ms 175-ms 250-ms 300-ms 350-ms 400-ms 450-ms 500-ms
delay, delay, delay, delay, delay, delay, delay, delay, delay,
key key key key key key key key key
C-2473A | C-2473B | C-2473C C-2473D C-2473E | C-2473F | C-2473G | C-2473H C-24731
19.4 96.8 171.8 266.6 292.5 344.0 370.5 457.0 503.0
19.6 101.0 172.2 274.6 304.5 351.0 379.0 462.5 506.5
20.2 101.4 176.6 274.8 306.5 358.5 390.0 466.5 508.5
20.4 102.0 176.6 280.6 309.5 362.0 400.0 468.0 528.5
21.0 102.0 178.6 281.2 310.0 364.0 405.5 469.0 530.0
21.4 102.2 178.8 282.0 310.5 364.5 408.5 471.0 531.0
22.0 105.0 179.0 284.2 312.0 365.0 409.5 471.0 531.5
22.4 105.2 180.2 285.0 312.0 370.0 416.0 471.5 537.0
22.4 106.8 184.4 285.8 312.5 370.0 429.5 472.5 537.0
22.4 107.6 184.6 286.8 313.5 371.5 432.0 476.0 537.5
22.4 108.0 185.4 290.2 316.0 372.0 434.5 476.0 539.0
22.6 109.0 189.8 292.0 317.5 374.0 434.5 476.0 541.0
22.6 109.6 190.8 292.8 318.0 381.5 435.5 477.0 544.5
22.6 110.2 192.0 294.2 319.5 384.5 439.0 477.0 545.0
22.8 110.6 193.6 294.8 320.5 385.0 447.5 478.5 552.5
23.6 110.8 195.2 295.4 320.5 386.5 448.0 478.5 556.5
24.4 112.6 197.2 295.5 321.5 387.5 454.5 479.0 569.0
26.0 114.4 199.4 295.6 327.0 389.5 456.5 479.0 574.5
27.4 114.6 201.6 299.6 327.0 391.0 460.5 480.5 575.0
29.8 119.4 210.4 312.0 335.5 412.0 474.5 488.5 580.0

DP Delay period.


12

ome! ]
| ro
}— H 4
2 =
L — KEY J
3 oy © Nominal
RH
. -— _
4 ee .
a a -— /~ 1st test series _
S 5 1—_1/— 2d test series
5 a /——_— 3d test series |
a -—
6 te
t— 4 4
7 H—e———_——_
}— rt 4
8 en
-—4 _|
5 =
l l l l ——
0 100 200 300 400 500 600

TIME DELAY, ms

FIGURE 6. - Delay times for manufacturer C’s detonators.

period detonator was actually less than
that for a shorter period detonator of
the same manufacturer (a criterion that
is expressed as t= 0). However, it
should be pointed out that this assump-
tion is a mathematical convenience; since
the “correct” value of t is not precisely
known, any finite value that it might be
assumed to have would, at this point, be
arbitrary, and the use of such a value in
drawing conclusions would make the con-
clusions arbitrary as well. However,
elementary calculations of the ability of
explosives to significantly move the coal
or rock at typical explosive-to-burden
ratios indicate that appropriate values
of t are of the order of magnitude of
10 ms.

It should be observed
reported herein represent an attempt
to survey the possibilities of overlap-
ping time under field conditions and do
not necessarily represent a critical

that the results

evaluation of detonator quality control
as such. Firing currents were chosen
to be representative of field use condi-
tions, which are not necessarily the same
as those firing currents that will result
in optimum detonator performance. In ad-
dition, the temperature at which the det-
onators were fired was not controlled,
and since there is alleged to be a small
temperature coefficient of delay time (of
the order of a few tenths of a percent
per degree Celsius), the reported firing
times may vary somewhat from those that
would be obtained under controlled tem-
perature conditions.

The three brands of coal-mine-type de-
lay detonators did not seem to differ
greatly in delay accuracies; all showed
a tendency toward overlap in the longer
delay periods. Whether the overlap rep-
resents a hazard in delay blasting in un-
derground coal mines is a difficult ques-
tion requiring further study.


A wide-band current transformer was em-

ployed to monitor the current pulse in
the firing circuit. Figure 2 shows a
typical firing current profile. The
current transformer output was 100 mV/A
of current flow in the circuit and was
monitored with an oscilloscope. The peak

firing current was 2.4 A and declined
exponentially at an average rate of about
0.21 A/ms, as shown in figure 2. Figure
3 shows a typical firing voltage signa-
ture of the blasting unit. As each deto-

mator fired, it shorted an ionization
probe (twisted pair), which in turn
caused a trigger circuit to send a pulse

to the oscilloscope.

Three separate lots of detonators of
each delay period for the three domestic
manufacturers were tested. Detonators
presented in appendix tables A-l, B-l,
and C-l were tested during the winter of
1982-83; those in tables A-2, B-2, and
C-2 during the winter of 1983-84, and
those in tables A-3, B-3, and C-3 during
the summer of 1984. The pulses were re-
corded with an accuracy of +0.25 ms.

This technique had previously been shown
to give reliable results on a millisecond
time scale.

S) Oscilloscope

; Wide band
lonization pulse transformer

probes

Variable power
Input resister set to
Dual trigger '500
circuit

Output Femco

25-20

blaster’

Input Triggerof [7 |} 1
10H
attenuator

FIGURE 1. - Schematic diagram of experimen-
tal setup used for detonator delay measurement.

on

~
If

FIRING CURRENT, A
fo) _—
i |

©)
oO
i)
aS

6

8 10 |l2 14 6 18

TIME, ms

FIGURE 2. - Typical firing current profile.


OVERLAP PROBABILITY FOR SHORT-PERIOD-DELAY DETONATORS
USED IN UNDERGROUND COAL MINING

By T. S. Bajpayee, ! Richard J. Mainiero,? and Je Edmund Hay?

ABSTRACT

The Bureau of Mines investigated coal-mine-type short-delay electric
detonators marketed by three domestic manufacturers to determine the
accuracy of delays and the probability of overlap between adjacent de-
lay periods. The Winzer index was computed and compared with the prob-
ability of overlap. A close agreement between the Winzer criterion and
overlap probability was demonstrated.

A permissible blasting unit capable of delivering a maximum firing
energy of 4.0 J and a digital oscilloscope were used to measure the
delay time with an accuracy of +0.25 ms. Another oscilloscope and a
pulse transformer were used to record firing current.

Experimental data indicated negligible overlap probability in detona-
tors of shorter delay periods: periods 1 to 4, which correspond to 25
to 250 ms. However, a significant probability of overlap was detected
in some detonators of longer delay periods: periods 5 to 9, which cor-
respond to 300 to 500 ms.

TMining engineer.

2supervisory chemical engineer.

3supervisory research physicist.

Pittsburgh Research Center, Bureau of Mines, Pittsburgh, PA.


A/ms

ms

nv/A

UNIT OF MEASURE ABBREVIATIONS USED IN THIS REPORT

ampere Q ohm
ampere per millisecond pet percent
joule s second
millisecond Vv volt

millivolt per ampere



13

APPENDIX A.--DELAY TIMES FOR MANUFACTURER A'S COAL MINE DELAY DETONATORS

TABLE A-1. - Delay times for manufacturer A's coal mine delay detonators--first test
series, arranged in ascending order and by designated nominal delay, milliseconds
DP 1, DP 2, DP 3, DP 4, DP 5, DP 6, DP 7, DP 8, DP 9,
25-ms 100-ms 175-ms 250-ms 300-ms 350-ms 400-ms 450-ms 500-ms
delay, delay, delay, delay, delay, delay, delay, delay, delay,
key key key key key key key key key
C-2379A_ | C-2379B C-2379C | C-2379D C-2360A | C-2360B C-2360C_| C-2360D | C-2360E
29.4 107.6 170.2 245.0 307.0 328.5 386.5 419.0 502.0
31.4 107.6 174.4 257.4 309.0 329.0 389.0 431.0 509.5
32.4 109.8 176.6 269.8 310.0 332.0 390.5 448.0 524.5
32.4 110.0 176.8 272.4 310.5 336.0 391.0 448.0 525.0
32.8 110.8 177.0 274.4 310.5 342.5 395.0 448.5 525.5
33.2 112.0 177.2 278.4 310.5 344.0 397.5 449.5 528.5
34.8 112.4 180.6 279.8 311.5 348.5 401.5 454.0 529.5
34.8 112.8 182.0 280.0 313.5 354.5 403.5 456.0 534.0
35.0 113.2 182.4 281.0 315.0 357.0 407.5 457.5 534.5
35.2 113.6 183.2 281.6 315.5 359.5 407.5 462.5 535.5
35.6 114.8 183.8 281.6 316.0 359.5 408.0 466.0 535.5
36.0 115.4 185.6 284.2 317.0 361.0 409.0 467.0 537.5
36.2 116.4 185.8 284.2 317.5 368.0 416.5 468.0 539.5
36.2 117.2 186.8 284.2 318.0 368.5 417.0 471.0 542.0
36.4 118.0 187.0 285.8 319.0 370.5 423.5 473.0 544.0
37.2 118.2 187.2 285.8 322.0 373.5 427.0 476.0 544.5
37.2 118.4 187.8 286.8 323.0 379.5 437.0 476.5 551.0
37.2 118.6 189.8 287.4 324.0 379.5 442.0 480.5 556.0
38.8 119.4 192.8 288.0 324.0 392.0 448.0 484.5 566.0
38.8 122.8 193.8 295.8 328.5 394.5 452.0 518.5 567.0

DP Delay period.

TABLE A-2. - Delay times for manufacturer A's coal mine delay detonators--second test
series, arranged in ascending order and by designated nominal delay, milliseconds

DP 1, DP 2, DP 3, DP 4, DP 5, DP 6, DP 7, DP 8, DP 9,
25-ms 100-ms 175-ms 250-ms 300-ms 350-ms 400-ms 450-ms 500-ms
delay, delay, delay, delay, delay, delay, delay, delay, delay,
key key key key key key key key key
C-2469A | C-2469B C-2469C | C-2469D C-2469E | C-2469F C-2469G | C-2469H | C-24691
26.2 95.8 181.6 253.4 276.0 333.0 409.0 455.0 502.0
27.8 99.2 183.2 262.6 284.0 342.0 412.0 455.5 508.5
28.0 99.4 183.2 262.6 287.5 344.5 413.5 459.5 509.0
28.2 99.4 183.6 265.8 290.0 346.0 415.5 459.5 509.5
28.8 99.6 184.4 271.8 290.5 347.5 416.0 460.0 509.5
29.0 100.0 184.8 272.4 292.0 355.5 418.0 460.0 513.0
29.4 100.4 186.5 276.6 293.0 360.0 424.5 460.5 513.0
29.6 100.8 187.0 277.4 294.5 360.0 427.5 462.0 514.0
30.4 101.6 188.6 279.4 294.5 362.0 436.0 463.0 519.0
30.4 101.8 189.0 280.0 295.0 363.0 440.0 463.0 521.5
30.4 102.2 189.8 280.4 295.5 364.0 441.0 465.0 523.0
30.4 102.8 191.4 283.6 296.0 364.5 442.5 467.5 524.0
30.6 103.4 191.4 283.8 298.5 364.5 444.0 470.0 524.0
30.8 103.6 191.8 283.8 301.5 364.5 444.5 471.0 525.0
31.2 105.0 192.5 284.2 302.5 366.5 445.5 471.0 525.5
31.4 105.0 194.2 284.8 303.0 367.5 449.0 475.0 525.5
31.6 106.0 195.4 285.4 305.5 369.0 457.0 476.0 536.5
32.0 106.8 198.4 286.0 311.5 371.0 458.5 487.0 537.0
32.2 107.8 201.4 286.2 312.0 373.5 470.5 491.0 538.5
32.8 108.6 204.6 292.6 313.5 385.5 536.0 496.0 541.0

DP Delay period.


Overlap probabilities
follows:
Let p,p(t)At be the probability that a
detonator of period n fires between times
(t - 1/2At) and (t + 1/2At). Then the
probability P, , ;(t,;) that a detonator
of nominal period n + 1 has already fired
at time t is

were computed as

ty
Ph + 1(t}) =f P, + y(t)dt. (2)

The probability P,(t;) of an “overlap
firing," i.e., that a detonator of period
n fires between times (t; - 1/2At,) and
(t,; + 1/2dt,), and that a detonator of
nominal period n + 1 has already fired at
time t, is the product of the above:

ty
Po(t) = Pa(t,)At; f Pp + y(t)dt. (3)
°

The overall probability Py, that over-
lap will occur is the integral of P,(t1)
over all possible times:

ey ty
Pog = f Palty) if Py + 1(t)dt dty. (4)
3

It is assumed that the distribution of
delay times is normal and that the stan-
dard deviation of the distribution is
given to sufficient accuracy by the esti-
mate of the standard deviation, i.e.,

EXPERIMENTAL

Detonator delay periods were measured
using a digital oscilloscope. The system
was designed to test two detonators sim-

ultaneously. As shown in figure 1, the
oscilloscope's trigger circuit was con-
nected to the blasting machine so that

the firing pulse would start the
measurement.

30 CFR 25.256 requires that a permis—
sible 20-shot blasting unit should be
capable of delivering adequate current to

time

1/2
o = | 18
, nN} (t; - =)? > (5)
i=l
where o, = the standard deviation for
nominal period n,
N = the number of observations,
t, = the observed firing times,
and ta = the mean firing time for

nominal period n;

PA(t) = 7 €

thus,

The overlap probability claimed for any
two adjacent periods n and n+ 1 was ob-
tained by_ inserting the corresponding
values of ty, th + 1, On, and of + 1 into
the expression given in equation 6 and
integrating according to equation 4 by a

straightforward second-order numerical
quadrature.
A computer program was developed to

compute the probability
samples of 20 detonators.

of overlap for

TECHNIQUE

consistently fire twenty short-period-
delay detonators through a series resist-
ance of 150 Q. This concept was utilized
in designing the firing circuit. A Femco
SF 25-20 permissible blasting unit? hav-
ing maximum capacitor energy of 4.0 J was

used in the tests. An external variable
resistor was used to add resistance in
series with the firing circuit, giving a

total resistance of 150 Q for testing the
detonators.

6U.S. Code of Federal Regulations. Ti-
tle 30--Mineral Resources; Chapter I--
Mine Safety and Health Administration,
Department of Labor; Subchapter D--Elec-
trical Equipment, Lamps, Methane Detec-
tors; Tests for Permissibility; Fees;
Part 25--Mulitiple-Shot Blasting Units;

Subpart C--Blasting Units Capable of
Detonating 20 Short-Delay Electric Deto-

nators; July 1, 1983.

Treference to specific equipment does
not imply endorsement by the Bureau of
Mines.





RI 8228

Bureau of Mines Report of Investigations/1985

Overlap Probability for Short-Period-Delay

Detonators Used in Underground
Coal Mining

By T. S. Bajpayee, Richard J. Mainiero, and J. Edmund Hay

UNITED STATES DEPARTMENT OF THE INTERIOR

onvaune
'VERSARY

rb)

MINES 75TH ANS


TABLE 1. - Summary of detonator delay measurement-~manufacturer A

Delay values, ms Overlap
Delay Nominal | Average | Low | High | Std. 100 o| (T,-T,) | probability, | Winzer
period (Ty) (Ta) (T,) | (Ty) | dev. Ta o pet index
(o)
FIRST TEST SERIES, KEYS C-2360 AND C-2379

Leveceee 25 35.1 29.4] 38.8) 2.5 7.12] 3.76 Neg 16.24
100 114.5 107.6] 122.8] 4.2 3.67 | 3.62 Ne . 9.15
175 183.0 170.2] 193.8) 6.2 3.39} 3.81 Nee. 741
250 279.2 245.0 | 295.8 | 11.4 4.08) 4.46 0 6 2.87
300 316.1 307.0] 328.5] 5.9 1.87 | 3.64 1.79 2.07
350 358.9 328.5 | 394.5] 19.8 5.52] 3.33 284 1.90
400 412.5 386.5 | 452.0] 20.1 4.87] 3.26 4.12 1.73
450 462.8 419.0 | 518.5 | 21.0 4.54| 4.74 “94 2.78
500 536.6 502.0 | 567.0 | 16.2 3.02 | 4.01 . .

SECOND TEST SERIES, KEYS C-2469
25 30.06 26.2] 32.8] 1.68] 5.59] 3.93 Ne, 19.46
100 102.46 95.8| 108.6] 3.32} 3.24] 3.86 non, 12.27
175 190.14 | 181.6] 204.6] 6.33] 3.33] 3.64 Non. 7.40
250 277.64 | 253.4] 292.6) 9.98] 3.59} 3.93 3 6 1.39
300 296.83 | 276.0] 313.5] 9.51] 3.21] 3.94 Ne 4.07
350 360.20 | 333.0] 385.5] 12.33 | 3.42] 4.26 5 2.57
400 440.03 | 409.0] 536.0] 28.52] 6.48) 4.45 17.389 “92
450 468.38 | 455.0] 496.0] 11.60} 2.48) 3.54 Ne 3.26
500 520.95 | 502.0} 541.0| 11.21] 2.15| 3.48 8. .
THIRD TEST SERIES, KEYS C-2552

25 25.10 18.8] 32.0] 4.19] 16.70] 3.15 Neg 15.97
100 104.27 100.8] 110.0 2.65 2.54 3.47 Ne, . 15.94
175 184.24 | 177.2) 192.0] 4.26] 2.31} 3.47 New. 8.78
250 255.23 | 244.0] 267.4) 6.89] 2.70} 3.40 0 39 2.63
300 293.99 | 271.5] 319.0] 12.97] 4.41] 3.66 Ne 4.64
350 363.30 | 347.0] 375.5) 7.42] 2.04] 3.84 61 2.99
400 401.25 | 382.5] 423.0] 10.32] 2.57) 3.92 Ne 4.18
450 467.15 | 446.5} 499.5] 11.92] 2.55] 4.45 10 55 1.26

Dosevece 500 497.75 | 452.5 | 530.0 | 21.07 | 4.23] 3.68 . :

Neg. Negligible.


450 ———

350

250 [-

150 [-

50

FIRING VOLTAGE, V

-s9 LL 1 1

2 0 2 4 6

8 10

TIME, ms

FIGURE 3. - Typical firing voltage signature.

RESULTS AND DISCUSSION

Measurements of actual delays arranged
in an ascending order are given in appen-
dix tables A-1, A-2, and A-3 for manufac-
turer A; tables B-l1, B-2, and B-3 for
manufacturer B; and tables C-1, C-2, and
C-3 for manufacturer C. Tables 1, 2, and
3 summarize the appendix tables for man-
ufacturers A, B, and C, respectively.
They present salient data such as nominal
delay time (T,), average of 20 measure-
ments (T,), lowest (T,) and highest (T,)
measured delay times, standard deviation
(0), ratio of standard deviation to aver-
age value (100 o/T,) (an estimate of dis-
persion of the observed data as compared
to the average), and (Ty-T,)/o (an indi-
cation of the spread in delay times, rel-
ative to standard deviation) for each de-
lay period. Overlap probability and Win-
zer index for consecutive delay periods
are also shown in tables 1, 2, and 3.
Experimental data given in table 1 for
the first lot of manufacturer A's coal

mine delay detonator series
and C-2379) indicate that--

1. Detonators of delay periods 1, 2,
3, and 4 show a Winzer index greater than
3 and have a negligible probability of
overlap.

2. Detonators of delay periods 4 and 5
exhibit low overlap probability and have
a Winzer index of 2.87.

3. The longest measured delay time of
period 5 corresponds to the shortest mea-—
sured delay time of period 6; the Winzer
index is less than 3, and some probabil-
ity of overlap exists.

4, For detonators
7, 8, and 9,
than 3 and a
overlap exists.

5. The tendency of dispersion of data
is quantified by ratios such as o/T, and
(T,-T.)/o. The o/T, ratios range from
1.87 to 7.12 pet, and (T,-T,)/o ratios
range from 3.26 to 4.74,

(keys C-2360

of delay periods 6,
the Winzer index is less
significant probability of


INTRODUCTION

Short-period-delay detonators are de-
fined as follows: "“'Short-delay electric
detonator' means a delay-type detonator
(blasting cap) the delay periods of which
range in nominal value from 25 to 500 ms,
and which will initiate (detonate) multi-
ple charges of high explosives in succes-
sion with one application of the firing
current" (30 CFR 25.2(e).)4 From a pro-
ductivity standpoint, the coal mining in-
dustry would prefer to incorporate nine
or more delay periods within the 500-ms
limit. However, increasing the number of
delay periods within the 500 ms requires
a decrease in the interval between adja-
cent delay periods, increasing the possi-
bility of detonators' shooting out of se-
quence (overlaps). This situation led
the Bureau to initiate a study of the ac~
curacy of delay periods of short-period-
delay detonators. Such data are es-
sential to the study of safe blasting
practices in underground coal mines.
This research was conducted under the Bu-~
reau's “Generation of Hazard Criteria and
Test Procedures for Explosive Products”
program.

The accuracy and precision of commer-
cially available coal mine delay detona-
tors were investigated. Three separate
lots of detonators of each delay period
marketed by three domestic manufacturers

were procured during the fall of 1982,
fall of 1983, and summer of 1984 and
tested.

Winzer> derived from statistical con-

siderations a nondimensionalized critical

Parameter for estimating a satisfactory
probability of “success” in delay blast-
ing, i.e., that the later hole of an

adjacent-period pair will fire at or
later than a given time after the earlier

4u.s. Code of Federal Regulations. Ti-
tle 30--Mineral Resources; Chapter I--
Mine Safety and Health Administration,
Department of Labor; Subchapter D--Elec-
trical Equipment, Lamps, Methane Detec-
tors; Tests for Permissibility; Fees;
Part 25--Multiple-Shot Blasting Units;
Subpart A--General Provisions; July 1,
1983.

hole. According to Winzer, a value for
the Winzer index, S, of less than 3 indi-
cates significant probability of overlap
between adjacent delay periods.

The Winzer index, S, is given by

= tn +1) > In = 7

“Zp T7z a)

s ,
Ton? + O(n + 1°)

where Tc, + 1) = average delay time for
period (n + 1) deto-

nators, s,

T, = average delay time for
period n detonators,
8s,

t = required time interval
between the firings
of adjacent holes, s,

Ocn + 1) = Standard deviation for
period (n + 1) deto-
nmators, s,

and o, = standard deviation for
period n detonators,
Ss.

The probability that two boreholes
primed with adjacent-period detonators
will fire within a given time interval
relative to each other can be calculated
from the knowledge of firing times, the
mean firing times, and standard devia-
tions of the firing times for each of the
two periods. However, this time inter-
val, the time requirement for the burden
to move out sufficiently so that the sub-
sequent shots do not fire in tight forma-
tion, is not precisely known. The most
liberal assumption of this time is zero
(see “Results and Discussion").

Swinzer, S. R., W. Furth, and A. Rit-
ter. Initiator Firing Times and Their
Relationship to Blasting Performance.
Pres. at 20th U.S. Symp. on Rock Mechan-
ics, Austin, TX, June 4-6, 1979, 10 pp.;
available from S. R. Winzer, Martin Mari-
etta Lab., Baltimore, MD.


16

TABLE B-3. - Delay times for manufacturer B's coal mine delay detonators--
third test series, arranged in ascending order and by designated nominal

delay, milliseconds

DP il, DP 2, DP 3, DP 4, DP 5, | DP 5-1/2, DP 6, | DP 6-1/2,/ DP 7,
25-ms 100-ms 170-ms 240-ms | 300-ms 350-ms 400-ms 450-ms 500-ms
delay, | delay, delay, delay, delay, delay, delay, delay, delay,
key key key key key key key key key
C-2575A | C-2575B | C-2575C | C-2575D | C-2575E| C-2575F C-2575G | C-2575H_ | C-25751
12.2 66.2 128.0 222.0 269.0 316.5 367.0 422.0 458.5
13.6 67.2 130.8 226.2 277.0 317.5 370.0 431.5 460.0
13.6 67.2 131.8 228.4 277.5 321.5 373.5 432.5 460.0
13.8 67.6 136.8 228.8 278.0 321.5 373.5 433.5 464.5
13.8 73.6 138.2 229.4 281.0 322.5 378.0 435.0 475.0
14.8 7564 139.8 229.4 281.0 322.5 378.0 438.0 477.0
16.4 76.8 141.6 233.6 286.5 325.0 379.0 438.0 478.0
16.8 77.8 141.8 234.2 287.0 325.0 379.5 447.5 478.0
17.4 79.8 144.0 234.4 289.5 327.5 382.5 448.5 479.5
17.6 80.6 144.0 234.4 291.0 327.5 384.0 452.0 484.0
17.8 81.4 147.4 236.4 291.5 330.0 389.5 453.5 484.5
18.2 83.2 147.8 236.6 291.5 331.0 390.0 458.5 486.0
19.8 84.8 149.8 236.8 294.0 332.0 390.0 460.0 487.5
19.8 84.8 151.0 238.4 294.0 337.5 396.0 460.5 488.5
20.4 85.2 156.2 238.4 294.5 338.0 396.5 465.5 489.0
20.6 86.0 156.2 240.2 299.0 340.5 399.5 476.5 493.5
20.6 86.4 157.2 241.2 299.5 341.0 400.0 478.5 496.0
22.4 88.8 157.8 246.0 304.0 345.5 401.5 478.5 496.0
22.6 91.8 162.0 247.0 307.5 352.5 404.0 483.5 497.0
24.6 99.0 162.0 256.0 344.5 359.5 412.5 488.0 499.0

DP Delay period.


Library of Congress Cataloging in Publication Data:

Bajpayee, T. S

Overlap probability for short-period-delay detonators used in under

ground coal mining.

(Report of investigations ; 8888)
Includes bibliographical references.
Supt. of Docs. nos: 1 28.23:8888.

1, Electronic detonators. 2. Blasting, 3. Coal mines and mining.
Mainiero, Richard J. Il, Hay, J. Edmund. Ill, Title. IV. Series:

Report of investigations (United States, Bureau of Mines) ; 8888.

TN23.U43  [TN803] 622s [6227.334] —_83-600392



Data given in table 1 for the second
lot of manufacturer A's coal mine delay
detonator series (key C-2469) indicate
that--

1. Detonators of delay periods 1,
2, 3, and 4 show a Winzer index greater
than 3 and a negligible probability of
overlap.

2. Detonators of delay periods 4 and
5 have a Winzer index less than 3 and a
significant probability of overlap.

3. Detonators of delay periods 5 and 6
show a Winzer index greater than 3 and a
negligible probability of overlap.

4, Detonators of delay periods 6 and
7 exhibit low overlap probability and a
Winzer index of 2.57.

5. Detonators of delay periods 7 and
8 have a Winzer index less than 3 and a
relatively high probability of overlap.

6. Detonators of delay periods 8 and 9
have a Winzer index greater than 3 and a
negligible probability of overlap.

7. The o/T, ratios range from 2.15 to
6.48 pet, and (Ty-T,)/o ratios range from
3.48 to 4.45.

Data given in table 1 for the third lot
of manufacturer A's coal mine delay deto-
nator series (key C-2552) indicate that—-

1. Detonators of delay periods 1,
2, 3, and 4 show a Winzer index greater
than 3 and a negligible probability of
overlap.

2. Detonators of delay periods 4 and 5
have a Winzer index of 2.63 and low prob-
ability of overlap.

3. Detonators of delay periods 5 and
6 show a Winzer index greater than 3 and
negligible probability of overlap.

4. Detonators of delay periods 6 and 7
show a Winzer index of 2.99 and very low
probability of overlap.

5. Detonators of delay periods 7 and 8
show a Winzer index greater than 3 and a
negligible probability of overlap.

6. Detonators of delay periods 8 and 9
show a Winzer index of 1.26 and a rela-
tively high probability of overlap.

7. The o/T, ratios range from 2.04 to

16.70 pet, and (T,-T,)/o ratios range
from 3.15 to 4.45.
Figure 4 shows the spread of delay

times for the three lots of manufacturer
A's detonators.

Data given in table 2 for the first lot
of manufacturer B's delay series (keys
C-2361 and C-2372) mainly indicate that--

1. Detonators of delay periods 1
through 7 exhibit a Winzer index greater
than 3, and there is a negligible proba-
bility of overlap. (There are only sev-
en delay periods within the 500-ms time
span).

2. The o/T, ratios range from 2.73 to

21.07 pet, and (T,-T,)/o ratios range
from 3.02 to 4.10.

Data given in table 2 for the second
lot of manufacturer B's delay series
(keys C-2470 and C-2475) mainly show
that--

1. Detonators of delay periods 1

through 5 exhibit a Winzer index greater
than 3 and a negligible probability of
overlap.

2. Detonators of delay periods 5 and
5-1/2 show a Winzer index less than 3 and
a relatively high probability of overlap.

3. Detonators of delay periods 5-1/2
and 6 show a Winzer index of 2.87 and a
low probability of overlap.

4, Detonators of delay periods 6 and
6-1/2 show a Winzer index greater than 3
and a negligible probability of overlap.

5. Detonators of delay periods 6-1/2
and 7 show a Winzer index less than 3 and
a relatively high probability of overlap.

6. The o/T, ratios range from 3.10 to
20.03 pet, and (Ty-Te)/o ratios range
from 2.90 to 4.62.

7. Table B-1 in appendix B lists seven
delay periods and table B-2 lists nine
delay periods between nominal delays of
25 and 500 ms. Introduction of two more
delay periods in table B-2 increased the
tendency of overlap.


1

H T T T T T
| [Re
H
Lr 4
2 -—e
EY
= K 4
3 — ¢ Nominal
= - —_
a 4 —
2 = — /__ 18st test series Ss
lu 5 o——_—_— 24 test series
oa = “3d test series +
5% —
}— r— 4
A
6 he
— I _
l
6 ly e+
; = =
| | l {+
(0) 100 200 300 400 500 600

TIME DELAY, ms

FIGURE 5. - Delay times for manufacturer B’s detonators.

5. The o/T, ratios range from 2.59 to

24.26, and (T,-T,)/o ratios range from
3.11 to 4.74.
Data given in table 3 for the second

lot of manufacturer C's delay series (key
C-2473) indicate that--

1. Detonators of delay periods 1
through 4 have a Winzer index greater
than 3 and a negligible probability of
overlap.

2. Detonators of delay periods 4 and
5 have a Winzer index less than 3 and
also exhibit a significant probability of
overlap.

3. Detonators of delay periods 5 and 6
have a Winzer index greater than 3 and a
negligible probability of overlap.

4. Detonators of delay periods 6
through 8 have a Winzer index less than 3
and also exhibit a significant probabil-
ity of overlap.

5. Detonators of delay periods 8 and
9 show a Winzer index of 2.93 and a low
Probability of overlap.

6. The o/T, ratios range from 1.48 to
11.24 pet, and (T,-T,)/o ratios range
from 3.50 to 4.63.

Data given in table 3 for the third lot

of manufacturer C's delay series (key
C-2586) indicate that--
1. Detonators of delay periods 1

through 5 have a Winzer
than 3 and negligible
overlap.

2. Detonators of delay periods 5
through 9 have a Winzer index less than
3 and exhibit significant probability of
overlap.

3. The o/T, ratios range from 3.55 to
9.99 pet, and (Ty-T,)/o ratios range from
3.41 to 4.43.

Figure 6 shows
times for three
detonators.

Zero was used for the parameter + in
calculating the Winzer index, and delay
periods were not considered to have over-
lapped unless a delay time for a longer

index greater
probability of

the spread of delay
lots of manufacturer C's


Report of Investigations 8888

Overlap Probability for Short-Period-Delay
Detonators Used in Underground
Coal Mining

By T. S. Bajpayee, Richard J. Mainiero, and J. Edmund Hay

UNITED STATES DEPARTMENT OF THE INTERIOR
Donald Paul Hodel, Secretary

BUREAU OF MINES
Robert C. Horton, Director


UNITED STATES
DEPARTMENT OF THE INTERIOR

BUREAU OF MINES
4800 FORBES AVENUE
PITTSBURGH, PENNSYLVANIA 15213

OFFICIAL BUSINESS
PENALTY FOR PRIVATE USE, $300

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INT-416




TABLE 2. - Summary of detonator delay measurement--manufacturer B

Delay values, ms __ Overlap
Delay Nominal} Average | Low | High | Std. 100 o| (T,-T,) | probability, | Winzer
period (T,) (T,) (Te) | (T,) | dev. Ta o pet index
(0)
_ FIRST TEST SERIES, KEYS C-2361 AND C-2372

Leseceee 25 14.1 10.6] 18.8] 2.0 [14.18] 4.10 Ne 3.62
100 61.7 31.0] 82.0] 13.0 | 21.07] 3.92 Neon. 5.33
170 153.1 137.6 | 174.6] 11.2 7.32] 3.30 Neo. 6.76
240 253.7 242.0 | 271.6] 9.8 3.86 | 3.02 New. 3.65
320 325.1 296.5 | 356.0 | 16.9 5.20] 3.52 Nea. 347
400 406.8 379.5 | 442.5 | 16.4 4.03 | 3.84 Ne. . 5.18

Teo cseeee 500 519.2 492.0 | 543.0 | 14.2 2.73 | 3.59 8. .

SECOND TEST SERIES, KEYS C-2470 AND C-2475

Leveeees 25 21.20 11.6{ 31.2] 4.25] 20.03] 4.62 Neg 6.96
100 90.38 65.4] 102.0] 8.98] 9.94] 4.08 Ne . 5.68
170 171.75 151.2 | 196.8 | 11.17 6.50] 4.08 New. 5.02
240 255.37 | 238.8 | 274.6 | 12.35 | 4.84] 2.90 Neo. 3.72
. 300 328.30 | 300.0 | 360.5] 15.21] 4.63] 3.98 V7 rn “94
5-1/2... 350 347.00 | 322.0 | 373.0] 12.91] 3.72] 3.95 “09 2187
Ooseeeee 400 403.70 | 378.0} 425.0] 14.96] 3.71} 3.14 Ne 3.54
6-1/2... 450 480.83 | 453.0] 511.5] 15.80] 3.29] 3.70 18 31 “90

Tocesece 500 500.70 | 470.0 | 530.0] 15.54] 3.10} 3.86 . .

THIRD TEST SERIES, KEY C-2575

Lesseeee 25 17.84 12.2] 24.6) 3.49] 19.58] 3.55 Neg 6.55
sees 100 80.18 66.2) 99.0) 8.85] 11.04] 3.71 Neg. 4.86
Beveeeee 170 146.21 | 128.0] 162.0} 10.30] 7.04] 3.30 Neg. 6.92
4, 240 235.89 | 222.0] 256.0] 7.88] 3.34] 4.31 Ne . 3.18
Sees 300 291.88 | 269.0) 344.5] 15.77] 5.40] 4.79 2 57 203
5-1/2... 350 331.73 | 316.5] 359.5] 11.63] 3.51] 3.70 Ne 3.23
Oreceeee 400 387.23 | 367.0] 412.5] 12.64] 3.26] 3.60 a 2.86
6-1/2... 450 454.08 | 422.0} 488.0] 19.64] 4.32] 3.36 12.05 1.17

Tosceees 500 481.58 | 458.5 | 499.0] 12.82] 2.66] 3.16 . :

Neg. Negligible.


10

= T I T T I
| bal
H
2 ef
= KEY 4
—_ .
3 erm ¢ Nominal
HH
4 —
a | 4 fist test series 4
(e) 5 +17 — 2d test series
x = H—_i1— 3d test series _|
a -——H
6 He—4
KH
+——
7 e+
al
el
8 —
——_+i
9 en
| | | | +1
ie) 100 200 300 400 500 600
TIME DELAY, ms
FIGURE 4. - Delay times for manufacturer A’s detonators.
Data given in table 2 for the third lot Figure 5 shows the spread of delay

of manufacturer B's delay series (key
C-2575) indicate that--
1. Detonators of delay periods 1

through 5 exhibit a Winzer index greater
than 3. and a negligible probability of

overlap.
2. Detonators of delay periods 5 and
5-1/2 show a Winzer index of 2.03 and

significant probability of overlap.

3. Detonators of delay periods 5-1/2
and 6 show a Winzer index greater than 3
and negligible probability of overlap.

4. Detonators of delay periods 6 and
6-1/2 show a Winzer index of 2.86 and low
probability of overlap.

5. Detonators of delay periods 6-1/2
and 7 show a Winzer index of 1.17 and
relatively high probability of overlap.

6. The o/T, ratios range from 2.66 to
19.58 pet, and (T,-T,.)/o ratios range
from 3.16 to 4.79.

times for the three lots
B's detonators.
Data given in table 3 for the first lot

of manufacturer

of manufacturer C's delay series (keys
C-2353 and C-2375) show that--
1. Detonators of delay periods 1

through 5 have a Winzer
than 3 and a negligible
overlap.

2. Detonators of delay periods 5 and 6
exhibit a Winzer index of 2.90 and a low
probability of overlap.

3. Detonators of delay periods 6, 7,
and 8 exhibit a Winzer index of less than
3 and a significant to relatively high
probability of overlap.

4. Detonators of delay periods
9 show a Winzer index of 2.95 and a
probability of overlap.

index greater
probability of

8 and
low