statistical investigation of the risk of accidental of the risk of accidental impact opening of mine shaft

32 Pages·2008·0.81 MB·English

Anglo Technical Division
A Division of Angglo Operations Limited
STATISTICAL INVESTIGATION
OOFF TTHHEE RRIISSKK OOFF AACCCCIIDDEENNTTAALL
IMPACT OPENING OF MINE
SHAFT DETACHING HOOKS
De Wet Strydom
Johann Wannenburg
Presentation outline
•• IInnttrroodduuccttiioonn
• Method
• Dynamic finite element analysis
• PProbbabbiilliisttiic siimullattiion
• Conclusion
2
Introduction
11999955 –– FFaattaall aacccciiddeenntt aatt NNoo. 22 VVaaaall rreeeeff
shaft
– LLooccoommoottiivvee ffeellll ddoowwnn sshhaafftt
– 104 fatalities
– Detachingg hook detached
– Rope elasticity was sufficient for rope to survive impact
– Many lives may have been saved
– Additional questions concerning the overall risk were raised
– A number of SIMRAC projects were launched to quantify the risk of
aann aacccciiddeennttaall ooppeenniinngg
3
Introduction
DDeettaacchhiinngg hhooookk ccoonnffiigguurraattiioonn
Pivot pin
Copppper shear
pin
Outer plates
Banana slot ppin
SSciissor pllattes
4
Introduction
Tyyppical opperation of a detachment hook
5
Introduction
• Since 1995, the South African Safetyy In Miningg
Research Council (SIMRAC) funded various
projjects aimed at quantifyyingg and mitiggatingg
these risks
W
•• oorrkk pprreesseenntteedd iinn tthhiiss ppaappeerr ppeerrffoorrmmeedd aass ppaarrtt
of SIMRAC project SIM 02 05 01, with aim to
eessttaabblliisshh mmeetthhooddoollooggyy ffoorr ffiinnaall qquuaannttiiffiiccaattiioonn ooff
risk for each shaft and setting of an acceptable
ssttaannddaarrdd.
6
Historical work
•
Greenway,
Hamashin and
Thomas
((11999966))
• Crichton and
Smith (1997)
• Wainwright
(1997)
• Wainwrigght
(2001)
7
Method
Survey
Actual hook resistance
Monte Carlo Simulation
Required minimum
Head Impact Analysis
Hook resistance
8
Dyynamic FEA: Model
• 1100 ddiifffferentt hhookks were moddelllledd
• Meshed only with Hex elements
• CCoonnttaacctt wwaass mmooddeelllleedd iinn bbeettwweeeenn aallll
contacting surfaces
• Rope stiffness to simulate 160m of
rrooppee
9
Dyynamic FEA: Strain rate model
Plastic behaviour
Johnson CCook strain rate model:
Failure point
( )⎛ ⎛ ε& ⎞⎞ 7x 108 826M40
σ = A+Bεn ⎜1+Cln⎜ ⎟⎟
y p ⎜⎝ ⎜⎝ε&0 ⎟⎠⎟⎠
AA=SSttattiic yiielldd sttrengtthh 6
B=Hardening parameter
5
n=hardening exponent a)
P
s (
C=strain rate parameter esstre 44 Elastic behaviour
ar
e
h
al s 3
n
mi
o
N
22
1
00
0 0.2 0.4 0.6 0.8 1 1.2
Displacement (mm) -3
x 10
SSplliitt hhopkkiinson bbar
10