AZF FERTILIZER PLANT EXPLOSION FACTS AND QUIZ

WE PRESENT HERE THE FACTS AND YOU HAVE TO BREAK THIS MYSTERIOUS CASE.A HUGE INVESTIGATIONAND 15 YEARS LATERNO REAL CLUES OF WHAT HAPPENED AND MORE IMPORTANT, WHY.

AZF INVESTIGATION

A HUGE EXPLOSION OCCURRED IN A CHEMICAL PLANT IN TOULOUSE , FRANCE

ON SEPTEMBER 21, 2001,WITHOUT ANY OBSERVED PRECURSOR SIGN. OCCURRED 10 DAYS AFTER SEPTEMBER 11, SAME DATE BUT 80 YEARS AFTER OPPAU, KILLED 31 AND INJURED THOUSANDS,THE MATCH TRIGGERING THIS DETONATION COULD NOT BE FOUND.FIRST FERTILIZER ACCIDENT WITHOUT A SINGLE PROOF OF WHY IT HAPPENED.

PURPOSE OF THE DOCUMENT• THE PURPOSE OF THIS DOCUMENT IS NOT TO

CRITISIZE THE HUGE WORK DONE BY THE COURT EXPERTS OR BY THEIR DELEGATED EXPERTS OR BY INDEPENDANT SPECIALISTS,

• THE PURPOSE OF THIS DOCUMENT IS TO SUM UP, IN A PEDAGOGIC WAY WHAT I FOUND RELEVANT TO THIS CASE AND COULD HELP TO SOLVE IT.

THE MAIN INVESTIGATION FAILURES ARE: THE DEBRIS PROJECTION HAS NOT BEEN STUDIED, IMPORTANT WITNESSES HAVE BEEN HEARD, BUT NOT BELIEVED, THE DESPERATE SEARCH LEADS TO STOP THE REAL

INVESTIGATION AND MANIPULATE THE FACTS TO FIT THE BEST GUESS.

ABOUT THE AUTOR• MY NAME IS XXXXX,• I AM A RETIRED ELECTRONIC DIPLOM ENGINEER,• I WORKED OVER 25 YEARS FOR MATRA / AEROSPATIALE

FRANCE AS HEAD OF TECHNICAL ASSISTANCE AND SAFETY FOR OUR CUSTOMERS IN FRANCE AND ABROAD.

• I WAS SPECIFICALLY IN CHARGE OF OUR MISSILES DEDICATED INFRASTUCTURE AND EVIDENTLY THE TM 5 -1300 WAS MY BIBLE, EVEN IF I CAME TO HATE THOSE UK UNITS.

• I PARTICIPATED TO DDESB SEMINARS.• I MUST CONFESS THAT THE AZF TOPIC INTERESTED ME

WHEN, IN 2009, I HEARD THAT THE TRIAL WAS TO BEGIN BUT THE MAIN QUESTIONS WHERE STILL UNANSWERED.

• AS FREE AND INDEPENDENT INVESTIGATOR,THE TRUTH , AND EXCLUSIVELY THE TRUTH, IS MY GUIDE.

• I TAKE THE OPPORTUNITY TO THANK THE US EXPLOSIVE SAFETY COMMUNITY FOR PROVIDING FOR FREE , MANY IMPORTANT DOCUMENTS AND TOOLS .

REFERENCE DOCUMENTS / SOFTWARE

• THE REFERENCE DOCUMENTS ARE EVIDENTLY THE REPORTS AND ALL OTHER AZF TRIAL DOCUMENTS,

• THE TECHNICAL REFERENCE DOCUMENTS WOULD BE TOO LONG TO BE LISTED, BUT ARE MAINLY US DEFENSE SAFETY DOCUMENTS.

• SOFTWARE USED IS MAINLY CONWEP, BEC V.4 FOR SCALED METRIC DISTANCES < 40 , A PERSONNEL EXCEL SHEET FOR DISTANCES ABOVE (BASED ON EMPIRICAL SCALING LAWS FOR TRUCK BOMB EXPLOSIONS) AND OTHER USEFULL EXCEL PERSONNEL TOOLS.

• I ALWAYS USE TRADITIONAL CHARTS (TM 5-1300 WITH DPLOT AMONGST OTHERS) TO MAKE SURE MY COMPUTATIONS ARE SOUND.

AZF INVESTIGATION AND TRIALTWO MAIN ACTIONS HAD TO BE TAKEN IMMEDIATELY

AFTER THE ACCIDENT : • QUICKLY SECURE THE AZF SITE (CLASSIFIED SEVESO II ) TO AVOID A FURTHER ACCIDENT, (DOMINO EFFECT),• SECURE ALL EVIDENCE FOR THE INVESTIGATION. • CLEARLY, SOME IMMEDIATE SAFETY ACTIONS HAD NEGATIVE EFFECTS ON THE INVESTIGATION.• I HAVE THE FEELING THAT SAFETY TOPICS ARE WELL PROCESSED, BUT POST ACCIDENT INVESTIGATION SEEMS MORE IMPROVISED.• EVIDENTLY, 10 DAYS AFTER WTC, THE INVESTIGATION FOCUSED ON A POSSIBLE TERRORIST ACTION. • TO PREPARE THE 2009 TRIAL OVER 50000 PAGES OF REPORTS AND DOCUMENTS ARE PILED UP.• THIS HUGE AMOUNT IS LINKED TO THE EFFORT OF FINDING SOMETHING, BUT ALMOST EVERYTHING IN THIS INVESTIGATION IS DISPUTED.

AZF TRIAL• THE AZF TRIAL HELD IN 2009 WAS HUGE, ASSOCIATIONS

TOOK PART (SIMILARLY TO A CLASS ACTION).• THIS CASE IS EXEPTIONALLY COMPLICATED, NO CLUES BUT

THOUSANDS OF DOCUMENTS / REPORTS, 800 WITNESSES, THE GUESS WORK WAS ON FULL PROGRESS.

• THE COURT EXPERTS, HAD TO MANIPULATE THE FACTS SO THAT THE CHLORE COULD WORK AS INITIATOR.

• THE JUDGE DECIDED THAT NO PENALITY COULD BE GIVEN, BASED ON SUPPOSITIONS AND PROBABILITIES.

• THE MINISTRY MADE AN APPEAL HELD IN 2011/2012 ON THIS DECISION, SINCE SAFETY RULES WERE NEGLECTED BY AZF, EVEN, IF NOT DIRECTLY RELATED.

• THE APPEAL CONDEMNED “TOTAL”, THE COMPANY OWNER BASED ON THE SAME SUPPOSITIONS, PROBABLY TO PLEASE THE MINISTRY AND THE VICTIMS.

• NOW THE SUPREME COURT CANCELLED THE APPEAL RULING AND A NEW TRIAL IS SCHEDULED IN JANUARY 2017.

AZF CHLORE THEORYWITHOUT ANY OTHER IDENTIFIED AGRESSOR, THE EXPERTS WERE SUMMONED TO FIND SOMETHING, AFTER SUCH LONG TIME AND SO MUCH MONEY SPENT.

THE THEORY IS AS FOLLOWS:• SOME UNDEFINED KILOS OF A CHLORE PRODUCT CALLED DCCNa HAVE BEEN, SOME 15 MINUTES EARLIER, ACCIDENTLY SKIPPED ON THE “AN” IN THE “BOX”, WHICH ACTS AS A TEMPORARY STORAGE.• THE CHLORE AND “AN” MIX, LED RAPIDLY TO THE PRODUCTION OF NCl3 AND HEAT, INDUCING A GENERAL DETONATION IN THE “BOX”,• THE MAIN “AN” STOCKPILE BEEING VERY CLOSE, IT ALSO DETONATED, TRIGGERED BY THE “BOX” BLAST.• THE EXPERTS JUST TOOK THE DISTANCE RELATION FOR SYMPATHETIC DETONATION, FORGETTING ONLY THAT “AN “ AS SUCH, IS NOT AN EXPLOSIVE!

AZF DESCRIPTION

AZF PLANT • AZF PLANT IS LOCATED FEW Km SOUTH OF

TOULOUSE (FRANCE), ON A 0.7Km2 LAND,• AZF IS PART OF AN IMPORTANT INDUSTRIAL

COMPLEX DEDICATED TO CHEMICAL PRODUCTS, SOME MILITARY ORIENTED,

• THE PLANT PRODUCES MAINLY AMMONIAC, UREA , NITRIC ACID AND AMMONIUM NITRATE.• AN AVERAGE OF 30000T DANGEROUS CHEMICALS

ARE TO BE FOUND ON THE SITE, LINKED TO THE PRODUCTION PROCESS OR FINAL PRODUCT.

• AZF IS CLASSIFIED SEVESO II

AZF PLANT

BLDG 221

AZF PLANT, SOME DAYS LATER !!

AZF BUILDING 221 STOREBLDG 221 IS PART OF A BUILDING COMPLEX

(221 TO 225). BLDG 221 IS DEDICATED TO THE STORAGE OF

OUT OF SPECIFICATION « AN » PRODUCED ON THE PLANT.

TWO TYPES OF « AN » ARE STORED IN 221 :• « AN » FOR AGRICULTURAL USE, CALLED

NAA WITH 33,5% NITROGEN, • « AN » FOR INDUSTRIAL USE, NAI WITH 34.5%N,

FOR EXPLOSIVE OR OTHER INDUSTRIAL USE.• HYDROFUGE ADDED PRODUCT, 0.2% IN MASS (CARBON ADDED 0.1% IN MASS).

BUILDINGS 221 TO 225 PERSPECTIVE VIEW BLDG 221- 225

221 -222 SEPARATING COLUMNS

BUILDINGS 221 / 222

JC TIRAT

ALUMINIUM ROOF

STOCKPILEBOX

LOADINGPLATFORM

STOCKPILES IN BOX AND MAIN PILE

35m10m

2.7m

BOX

“AN” STORED IN BUILDING 221

MAIN « AN » STOCK IS ESTIMATED AT 420 TONS:• 380T, OF WHICH 75% NAA , 25% NAI, ρ = 800Kg / m3

• 40 T AS A POLLUTED CRUST LAYER , ρ = 1200Kg / m3. (THE CRUST LAYER, NOT UNDER THE STOCKPILE IS

IGNORED ≈ 20T ).« AN » IN THE  BOX 11,5T :• 10 T NAA AND 3 PILES NAI , 500Kg EACH, (8.5 T CRUST LAYER IS IGNORED).MOST PROBABLY 50% OF THE « AN » IN THE BOX

PARTICIPATED TO THE DETONATION BUT CAN BE NEGLECTED (ONLY ≈ 4T EQUIVALENT TNT).

TOTAL MASS, USED FOR FURTHER COMPUTATION: 420T

“AN” STOCKPILE ESTIMATION • M , UNDETONATED “AN”, LIGHT CONFINEMENT

• C + Cr (CRUST) = DETONATED “AN” =>M + C + Cr = 420T,

THE CRUST HAS A 50% BETTER TNT EFFICIENCY, • SO ФB *( C +1,5*Cr – M / 5) = 60T TNT (BASED ON BLAST

EFFECT ESTIMATION),• ФB IS THE AN => TNT FACTOR (BLAST SOLUTION),• M / 5 , FOR THE « AIR » ENERGY LOST BY EJECTING

« M » AT ≈ 800m/s , (SIMILAR GURNEY).

M

C

Cr

STOCKPILE BASED ON CRATERIF USING CONWEP OR OTHER CHARTS,THE CRATER IS COHERENT WITH A BARE TNT CHARGE OF 100T ON ASPHALT (SEE NOTE), THEREFORE WE CAN WRITE: ФC *[1.2*(C + 1.5*Cr) + M / 8 ] = 100T,ФC IS THE AN => TNT FACTOR (CRATER SOLUTION),1.2 IS THE COEFFICIENT FOR THE HIGHER GROUND ENERGY, AIR / GROUND SURFACE RATIO FOR SUCH CHARGE 0.55/ 0.45 (COMPARED TO STANDARD HEMISPHERIC 0.67 / 0.33), M / 8 FOR THE LIGHT CONFINEMENT EFFICIENCY. NOTE : FOR CONWEP A MIX ASPHALT / CONCRETE COVERED SOIL HAS BEEN USED INSTEAD OF THE CONCRETE, SINCE THE 0.15m THICK, LIGHT REINFORCED CONCRETE SLAB, IS DAMAGED, EATEN AND WEAKENED BY THE « AN » PILE ABOVE.

STOCKPILE BEST FITDIFFERENT Ф SOLUTIONS FOR THE PILE :* M = 180T => C +1,5Cr = 260T AND ФC = 0.27 ФB = 0,30* M = 200T => C +1,5Cr = 240T AND ФC = 0.30 ФB = 0,32* M = 220T => C +1,5Cr = 220T AND ФC = 0.34 ФB = 0,34 * M = 240T => C +1,5Cr = 200T AND ФC = 0.39 ФB = 0,37 * M = 260T => C +1,5Cr = 180T AND ФC = 0.47 ФB = 0,40

THE BEST SOLUTION IS GIVEN BY ФC ≈ ФB, => M = 220T , C = 160T, Cr = 40T WITH

ФPILE ≈ 0.34 AND ФCRUST ≈ 0,5

TOTAL CHARGE EQUIVALENT : 75T OF TNT

THE 160T DETONATED AND SIMPLIFIED PILE / CRUST COULD THEREFORE BE AS FOLLOWS:• CRUST AVERAGED 35m x 10m x 0.1m x 1.2T/m3 ≈ 40T,• PILE AVERAGED 25m x 6m x 1.3m x 0,8T/m3 ≈ 160T.THE EQUIVALENT TNT IS 0.34 * 160T + 0,5*40T = 75T, WITH EFFECTIVE BLAST EFFECT ► 60T, WITH EFFECTIVE GROUND EFFECT ► 100T. IF WE CONSIDER THIS PILE TO BE INITIATED EAST, THE INITIATION POINT IS SOME 6m FROM THE BOX SEPARATING WALL AND ON PILE LONGITUDINAL AXIS.

DETONATED STOCKPILE

DETONATED CRUST / STOCKPILE

INITIATION 1,3m

25m

PILE

CRUST

35m

6m

6m

10m

“AN” DETONATION COMPARED TO TNT

• THE SIMPLE « AN » DETONATION FORMULA IS : NH4NO3 = N2 + 2H2O + ½ O2

• THE DETONATION ENERGY IS 1400 kJ / kg COMPARED WITH 4200kJ / kg FOR TNT THE ENERGY RATIO « AN » / TNT = 0.33• THE « AN »REACTION RELEASES 3.5moles / 0.08Kg

≈ 43 moles OF GAZ PER Kg OF « AN » AT ≈ 1700K .

• THE MUCH HIGHER ANFO ENERGY IS LINKED TO THE EFFICIENT USE OF THE LOST OXYGEN.

METEOROLOGICAL DATAS 1

AT 10H 17: 55 , PRESUMED LOCAL TIME OF DETONATION, THE CONDITIONS ARE:

• TEMPERATURE 17.2°C,• PRESSURE 997 mbar, (ALTITUDE 158m),• HUMIDITY 88%,• TEMPERATURE INVERSION 770m TO 970m, (SEE GRAPH HEREAFTER) ΔT = 1.5°C, BUT

MEASURED 3 HOURS LATER,• CLOUDY, AVERAGE SOLAR IRRADIATION

700W / m2

METEOROLOGICAL DATAS 2• WIND ≈ 7 m / s GUSTY, DIRECTION ≈ 150°, COMING

FROM SOUTH EAST, • MAXIMUM WIND PRESSURE ( WITH GUST SPEED ) FOR

10m/s => Pa = ρ*V2/ 2 = 1.2*100 / 2 = 60Pa = 0.6mbar.

BLAST EFFECT• OUTSIDE• INSIDE BUILDING

CALCULATED BLAST PRESSURES, FOR 60T TNT

WIND 7m/s

100mbar 550m 50mbar 950m 20mbar 1800m 10mbar 3000m 5 mbar 5000m

BROKEN WINDOWS

THE RING COLOUR AND DIMENSION GIVES THE PERCENTAGE OF BROKEN WINDOWS AT A GIVEN DISTANCE IN METERS.

BLAST ESTIMATION FROM DAMAGES

CHARGE20mbar average distance 1.8Km

50mbar average distance 1Km

NORTH

EAST

OUTLINES FROM ORANGE

TO BLUE REPRESENT :

200,140,100,70, 50, 20 mbar

ZOOM ON GZO VICINITY

THIS BLAST STRENGTH REMINDS THE ROCKET EFFECT ON THE EAST

SIDE OF THE CRATER

CHARGEHEMISPHERICAL 200mbar

EAST

50

SCHOOLS CLOSED FOR REPAIR

NORTH 5 mbarDefinitivelyMany monthsOver 4 weeksOver 2 weeksOver 1 weekLess 1 weekFew days

7 mbar10 mbar18 mbar

47 mbar

113 mbar

OVERPRESSURES

FOR 60T TNT

WIND 7m/s

BLAST EFFECT EAST

DETONATION GAS PATH

EAST

BLAST EFFECT• WE HAVE TO CONSIDER A LONG ALMOST RECTANGULAR

CHARGE, WITH A 4 / 1 RATIO, IN THE NEAR FIELD,THE SHAPE OF THE CHARGE PLAYS AN IMPORTANT ROLE,

• OBVIOUSLY IT HAS ALSO PLAYED A ROLE IN THE FAR FIELD SINCE THE HIGHEST OVERPRESSURES ARE ON AN ALMOST NORTH SOUTH AXIS,

• THE DETONATING PROCESS LASTS UP TO 25m / (3500m/s) => 7ms, (3500m/s IS THE THEORETICAL “AN” DETONATION SPEED), DEPENDING ON INITIALIZATION POINT.

• WINDOW BREAKAGE OR NOT, DEPENDS ON DISTANCE BUT ALSO ON WIND AND WINDOW BLAST ORIENTATION (FULL REFLECTED WAVE PRESSURE IS TWICE THE DIRECT WAVE).

• 5 mbars INCIDENT , IS CONSIDERED AS THE LOWER GLASS BREAKAGE LIMIT FOR CORRECTLY INSTALLED WINDOWS.

• THE NEAR FIELD EAST SIDE BLAST REMINDS A ROCKET GAS PLUME SHAPING THE CRATER END.

THE EQUIVALENT TNT IS CONSISTENT WITH 60T TNT CONSIDERING THE DAMAGE / DISTANCE CHARTS.

BLDG 221 § 222 BLAST EFFECT• FOR COMPUTATION,THE IMPORTANT LENGTH OF

THE BUILDING MUST BE TRUNCATED,• THE DOOR EAST, ALWAYS OPEN,THE IMPORTANT

LENGTH OF THE BUILDING AND THE ALUMINIUM ROOF ACT AS IMMEDIATE / FRANGIBLE VENTS,

• ALL OTHER WALLS ARE RAPIDLY DESTROYED AND PARTICIPATE TO THE RAPID GAS VENTING.

• THE STRESS / BLAST IMPULSE ON ANY BUILDING PART IS LINKED MAINLY TO THE CHARGE DIRECTLY FACING IT ,

• THE CHARGE LENGTH OF ≈ 25m IS TAKEN INTO ACCOUNT, THE BLAST IMPULSE IS AVERAGED OVER THIS WALL LENGTH FACING THE CHARGE.

BLDG 221 § 222 BLAST EFFECTBASED ON CONWEP COMPUTATION PRINCIPLES WE

OBTAIN APPROXIMATIVE IMPULSES OF : 1 bar*s = 7000 Psi*s ON THE SOUTH SIDE, 1 bar*s = 7000 Psi*s ON THE NORTH SIDE, 0.50 bar*s = 3450 Psi*s ON THE EAST SIDE, 0.10 bar*s = 700 Psi*s ON THE WEST SIDE, 0.70 bar*s = 4800 Psi*s ON THE ROOF,

THESE ABOVE VALUES ARE THE AVERAGE BLAST IMPULSES ON THE WALLS , A MORE DETAILED IMPULSE DISTRIBUTION IS SHOWN ON THE GRAPH FOR THE SIDE WALLS, VALID FOR THE 25m LENGTH, FACING THE DETONATING PILE.

HEIGHT

DETONATING STOCK PILE

GAS PRESSURE

GAS PRESSURE CONSIDERATION THE GAS PRESSURE IS COMPLICATED TO ESTIMATE SINCE

THE DETONATION HAS A DURATION BETWEEN 3,5 ms (IF CENTER INITIATED) AND MAXIMUM 25m / 3500m/s = 7ms (END INITIATED).THE BUILDING 221 CAN BE CONSIDERED AS COMPLETELY DEMOLISHED IN LESS THAN 4ms,THE HOT (1700K) GAS EXPANSION, INITIALLY AT 800m/s , REACHES THE ALREADY COLLAPSED WALLS (SCHOCK WAVE), NO GAS PRESSURE ACTS ON THE BUIDING, EVEN IF THE DETONATION LASTS ONLY 3,5ms,BUT THE GAS EXPANSION IS EFFICIENT TO ACCELERATE FURTHER, THE LOW SPEED FRAGMENTS IN ITS PATH,IF NEEDED FOR SIMILAR CASES THE GAS PRESSURE MUST BE COMPUTED BY THE FORMULA PV = nRT (ABSOLUTE PRESSURE) WHICH AVOIDS TO GUESS AN EQUIVALENT TNT; FOR BIG STRUCTURES , CHECK WHEN GAS REACHES THE WALLS AND THE GAS IMPULSE ACTS ON THE STRUCTURE.

MISSILES / FRAGMENTS

BLDG 221 § 222 FRAGMENTS UNFORTUNATELY, IN THE FRAME OF THE ACCIDENT

INVESTIGATION, THIS TOPIC HAS NOT BEEN STUDIED , IT WOULD CERTAINLY HAVE HELPED TO UNDERSTAND A LITTLE BETTER THIS UNBELIEVABLE DETONATION, APPROXIMATELY 18 MAJOR IMPACTS HAVE BEEN REPORTED ON AZF SITE, SOME PERFORATING BUILDING ROOFS AND OTHERS LEAVING SIGNIFICANT CRATERS. FOR MOST IMPACTS THE BROKEN CONCRETE AND STEEL DEBRIS HAVE BEEN PHOTOGRAPHED AND COLLECTED BUT NOT ANALYZED, ALMOST ALL DISTANT AND SIGNIFICANT FRAGMENTS ARE FROM THE 221 CONCRETE SLAB AND THE 221-222 SEPARATING COLUMNS, THESE COLUMN PARTS ARE EASY TO RECOGNIZE DUE TO THE RECENT CONCRETE AND SPECIFIC REBAR.

FRAGMENT GENERALITIES• FRAGMENT DISTANCE IS MAINLY FUNCTION OF INITIAL

SPEED, MASS, DRAG AND EJECTION ANGLE.• FRAGMENTS AT VERY LOW EJECTION ANGLES ARE

DANGEROUS ALONG MOST OF THE FLIGHT PATH, • FOR THE HIGH PARABOLIC TRAJECTOGRAPHIES , THE RISK

IS MUCH LOWER DUE TO ARRIVING IMPACT ANGLES > 70° ,• SECONDARY FRAGMENTS QUANTITY REPARTITION f(MASS)

IS USUALLY APPROXIMATED AS FOLLOWS: M < 0.1Kg , 55% , 0.1 < M > 5Kg, 42% AND M > 5Kg , 3%

ABSTRACT FROM BOMB FRAGMENT, RISK STUDY

Number of fragments

Increasing Weight

BLDG 221 § 222 FRAGMENTS FOR A BOMB,THE CASING IS IN DIRECT CONTACT WITH

THE HUGE EXPANDING GAS PRESSURE, THEREFORE THE CASING FRAGMENTS ARE EJECTED AT TREMENDOUS SPEED (see Gurney / Mott for distribution), THOSE FRAGMENTS ARE DURING SOME 100m IN ADVANCE OF THE SHOCKWAVE, BUT THEN, DUE TO THEIR DRAG, ARE OVERTAKEN BY THE SHOCKWAVE. HERE THE SITUATION IS DIFFERENT, A MUCH SMALLER IMPULSE IS GIVEN TO THE BUILDING FRAGMENTS, THE IMPULSES, ESTIMATED BEFORE, WILL LEAD TO FRAGMENTS / MISSILES WITH VELOCITIES RANGING FROM 100 UP TO 500m/s DEPENDING ON FRAGMENT CHARACTERISTICS, DISTANCE AND GEOMETRY TO BLAST. IN THIS CASE,THE SHOCKWAVE IS WELL IN ADVANCE OF SUCH FRAGMENTS DUE TO MODERATE SPEED / ERTIA.

BLDG 221 § 222 FRAGMENTS THE CONCRETE AND BRICKS OF THIS 80 YEARS OLD BUIDING ,

WEAKENED BY THE « AN » HAVE BEEN PULVERIZED AT CLOSE CHARGE DISTANCE, THE STEEL PARTS FROM THE ROOF, ALSO WEAKENED AND HIGHLY CORRODED HAVE BEEN EJECTED AT GREAT DISTANCES, THE ROOF COVER, ALUMINIUM SHEETS , CRUSHED BY THE BLAST, HAVE BEEN FOUND IN QUANTITIES, NORTH WEST, FOLLOWING THE WIND DIRECTION. THE BLAST IMPULSE DECREASES WITH INCREASING, STRUCTURE HEIGHT , THEREFORE THE HIGHEST VELOCITIES ARE THOSE UNDER LOWER EJECTION ANGLES. THE WALL FRAGMENTS ARE EJECTED FROM 0° TO APPROX 40° ELEVATION, HIGHER EJECTION ANGLES ARE MAINLY FOR ROOF STRUCTURE FRAGMENTS. IN THIS RANGE OF PARAMETERS, FRAGMENT SPEED IS APPROXIMATED BY SPEED m/s = IMPULSE IN Pa*s / FRAGMENT AREA MASS IN Kg /m2.

AZF , IMPORTANT FRAGMENT IMPACTS

THE MOST IMPORTANT FRAGMENTS ARE:• 221 CONCRETE SLAB• 221 - 222 COLUMNS,• BOX –PILE SEPARATING WALLMANY FRAGMENTS ARE EJECTED UNDER RELATIVE AZIMUT + 15°,THIS ANGLE REFLECTS A CORRESPONDING CHARGE (PART) ORIENTATION.UNDER -40° A BIG COLUMN PART IS EJECTED, FALLS ON A CAR (R5) AND FINALLY LEAVES A SIGNIFICANT CRATER (SEE HEREAFTER)

FRAGMENT TRAJECTOGRAPHY 80000Pa*s, 32°, Cx 2

AVERAGE SMALL BUILDING FRAGMENTS

COLUMNS 221 - 222 FRAGMENTS

THESE FRAGMENTS CAN EASILY BE IDENTIFIED BY THE STEEL REINFORCEMENT OF THE CONCRETE PILLAR AND FOR SOME BIG PIECES BY THE ROOF SUPPORTING STEEL LATTICE .

FLOORCONCRETE SLAB

STEEL LATTICE COLUMNSUPPORTING THE ROOF

1.80

m

0.8m

MASS ≈ 2200KgAREA DENSITY 1670 Kg / m2

COLUMNS FOUND IN CRATER VICINITY

COLUMNS 221 - 222 FRAGMENTS • AZIMUT 0° IS RELATIVE (≈ SOUTH)

• BLACK DOTS ARE SUPPOSEDLY THE 10 COLUMNS FOUND IN CRATER VICINITY (12 TO 19),• COLUMN 19 (MARKED VIII ) WAS STILL STANDING UPRIGHT ,• COLUMN 12 RECEIVES AN ESTIMATED 20000Pa*s IMPULSE, SO WE TAKE THIS VALUE AS THE POWER NEEDED TO BREAK AWAY AND MOVEMENT INITIATION,• COLUMNS 2 TO 7 RECEIVE AN ESTIMATED IMPULSE OF 220000Pa*s,• TO EJECT THESE COLUMNS WE HAVE 0.65*(220000 - 20000)Pa*s =130000Pa*s , (0.65 FOR CIRCULAR COLUMN / EFFICIENCY FACTOR) .

CAR IMPACT

EMPALOT BLOCK 221

R5 Az - 40°

345

6

8

10

7

9

15

1112

1314

16

171819

0°

?

25m

12

6m

a

d

b

e

c

222

BOX

COLUMN OR PART, PERHAPS Nr8, FALLEN ON CAR

CRATERDiam. 0.8m Depth 0.2m

ONE CAN ASSUME THAT AT LEAST, THE HALF UPPER COLUMN HAS HIT THE CAR AT ≈ 50m/s, BEFORE IMPACTING THE GROUND AT ≈ 30m/s, DISTANCE 420m, Az – 40° , SOUTH- WEST, ELEVATION IMPACT ANGLE ≈ 40°, CRATER DEPTH COHERENT WITH A FINAL SPEED OF 30m/s.

COLUMN STEEL LATTICE

SCATTERED DEBRIS

CAR FRONT DETAIL

40°

DETAIL

HEAVY PROJECTIONS TRAJECTOGRAPHY 130000Pa*s, 32°, Cx 2

CALCULATED FOR THE COLUMNS PARTS, BLDG 221-222 SEPARATION

POSSIBLE CAR IMPACT

HEAVY PROJECTION, EMPALOT BLOCK

THIS REINFORCED CONCRETE BLOCK FELL IN A SUBURB CALLED EMPALOT, 1600m FROM AZF CRATER!

REBAR

HEAVY PROJECTION, EMPALOT CONCRETE BLOCK THIS FRAGMENT HAD A MASS APPROX 350KG , PROBABLY VERY COMPACT, LOW Cx , 1600m ! SUCH DISTANCE FOR A CONCRETE BLOCK SEEMS EXEPTIONNAL, THE HEAVY REBAR SHOULD MAKE ITS IDENTIFICATION EASY, FOR SUCH DISTANCE AN IMPULSE > 2bar*s IS NEEDED. FRAGMENT EJECTION ANGLES COULD HELP UNDERSTAND THE PILE / BOX RELATIONSHIP.

THIS INCREDIBLE FRAGMENT HAS NOT BEEN ANALYSED AND WE HAVE NO CLUE OF ITS ORIGIN!!

AS IS KNOWN, THE USUAL MAXIMUMTHROW DISTANCE FOR SECONDARY FRAGMENTS IS IN THE PERPENDICULARBUILDING AXIS.

SOUNDS

EXPLOSION SOUNDS• IN MANY PLACES, AROUND THE TOWN, RECORDED

CONFERENCES WERE HELD SO AS ONE RADIO STATION EQUIPPED WITH PROFESSIONAL SOUND EQUIPMENT,

• BASICALLY THE TAPE RECORDERS ARE LIMITED IN THE LOW FREQUENCY BAND AND HAVE NO TIME BASE.

• THESE RECORDINGS HAVE BEEN STUDIED BY NOT LESS THAN THREE DIFFERENT EXPERTS !!

• TWO MAIN NOISES, SIMILAR TO EXPLOSIONS ARE HEARD,• THE RECORDS, CORRECTED FOR TAPE SPEED VARIATIONS

REVEAL THE TIME DIFFERENCE OF E1 AND E2 AT THE DIFFERENT LOCATIONS,

• E2 IS OBVIOUSLY THE AZF BLAST ARRIVAL AND E1 WAS BELIEVED TO BE THE SEISMIC WAVE ARRIVAL ON THE BUILDING, INDUCING THE E1 RECORDED SOUNDS,

• INDEED, EVEN IF SUCH DATA IS NOT WELL DOCUMENTED THE TIME DIFFERENCES ARE COHERENT WITH SUCH EXPLANATION AND PROPAGATION CHARACTERISTICS.

EXPLOSION SOUNDS

EXPLOSION SOUNDS

THE TOP LEFT TABLE GIVES THE METEOROLOGICAL DATAS AND COMPUTED SOUND SPEED, IT USES 60000Kg AS BLAST EFFECT CHARGE FOR Ta CALCULATION,THE TOP RIGHT TABLE SHOWS THE DIFFERENT SITES WITH MEASURED SEISMIC SPEEDS AND ARRIVAL TIMES THE MEASURED TIME INTERVAL AT THE RECORDING PLACES AND THE THEORETICAL TIME INTERVAL COMPUTED,(RED BOXES TIME DIFFERENCE),THE LOWER TABLE GIVES THE CALCULATED BLAST ARRIVAL TIME, WIND CORRECTED.

AS CAN BE SEEN THERE IS A GOOD MATCH FOR 5 SITES VALIDATING THE SOUND E1 AS BEEING OF SEISMIC ORIGIN.

SOUND RECORDING PLACES

WIND

URSSAF

POUVOURVILLE

H DR P

OMP

E D

BLAGNAC

A F

ABREUVOIR

TELEPHONE CONVERSATION

H P

AZF

GOOGLE MAPS

SOUND LEVEL RECORDER

• THIS SONOMETER IS DEDICATED TO MONITOR AIRCRAFT NOISE, SOUTH EAST AND 3840m FROM AZF,• THIS RECORDER WOULD HAVE DEFINITIVELY NAILED DOWN THE TIME OF AZF DETONATION BUT NO LUCK , THE EQUIPMENT, RECENTLY INSTALLED, WAS NOT YET LINKED TO AN OFFICIAL TIME BASE, IT HAD ONLY THE COMPUTER TIME, SET FEW MONTHS BEFORE.• THE AZF BLAST, GOING UPWIND NEEDS 11s TO ARRIVE AT THE SOUND MONITORING STATION,• OBVIOUSLY THERE IS A BIG TIMING PROBLEM , SINCE THE BLAST ARRIVAL IS 10H18:18 , MINUS 11s , WHICH PLACES THE To AT 10H18:07 , UNREALISTIC.

SOUND LEVEL RECORDING SATURATED LEVEL ?

OVERFLYING AIRCRAFTS

45dBA NOISE LEVEL

ESTIMATED SENSITIVITY 1Pa,NO PRIOR EXPLOSION TO BE SEEN

BEFORE AZF, ON THIS RECORD

CRATER

AZF CRATER AND VICINITY

PRILLING

TOWER

EAST

GARONNE RIVER

NORTH

CRATER PROFILE WITH BUILDING

MAIN STOCKPILE

“BOX” PILES

MAX DEPTH 8,0m

VOLUME 8700M3

45m

65m

BLDG OUTLINE

NORTH

CRATER PROFILE / CHARGE

CRATER BOTTOM

Box

CHARGE ESTIMATION

CENTRAL PEAK

CRATER RIDGE

CRATER EAST END BLAST PROFILED

http://www.esic-sn.fr/PDF/ESIC-XYZ-AZF.pdf ISIG

CRATER PROFILE• AZF CRATER IS ELLIPTIC ≈ 65 x 45 x 8m , FINAL VOLUME 8700m3 , • THE AZF CRATER DIMENSIONS MATCHES AN

EQUIVALENT TNT CHARGE OF ≈ 100Tons.• THE CRATER PROFILE IS SYMETRIC ACROSS EAST/ WEST AXIS BUT NOT SYMETRIC FOR

NORTH / SOUTH AXIS, LOW SLOPE EAST 11° AND 30° IN THE 3 OTHER DIRECTIONS.• THE WATER BED LEVEL IS ≈ - 3m• CRATER PROFILE FAVOURS A DETONATION

INITIATION EAST, BUT GEOLOGICAL DIFFERENCES EAST / WEST QUESTION THIS.

CRATER CONSIDERATIONS• THE CRATER PROFILE IS FUNCTION OF THE VERTICAL

CHARGE DENSITY,THAT MEANS, IN THE CASE OF AN EXPLOSIVE STOCKPILE ,THE CRATER IS DUG IN THE GROUND AS A MIRROR OF THE EFFECTIVE DETONATING PILE ABOVE.

• THIS MIRROR CAVITY HAS AN AMPLIFICATION FACTOR FUNCTION OF CHARGE / SOIL TYPE,

• THE CAVITY, COULD ALSO MODELLED BY THE CHARGE INITIATION POINT AS FOR SEISMIC SIGNATURE (TO BE STUDIED)

• BLUE PROFILE, CENTER INITIATION,HOMOGENEOUS SOIL RED PROFILE AZF.

CRATER EAST PROFILE

EAST

• THE CRATER PROFILE ON THE EAST SIDE SEEMS SHAPED BY A GAS PLUME SIMILAR TO A ROCKET ,• IN LESS THAN 1ms, 20T OF GAS AT 1700K ARE EJECTED TO THE REAR AT TREMENDOUS SPEED, IT COULD WELL EXPLAIN THE EAST SIDE CRATER GROUND SHAPING.• THEREFORE, THE DIFFERENT ASPECTS OF THE CRATER PROFILES ARE CONSISTANT WITH AN EAST SIDE START OF THE DETONATION (THIS, AS EVERYTHING ELSE IS DISPUTED).

EXPLOSIVE GASES

SHOCK FRONT

SEISMIC

MY SEISMIC (IN)COMPETENCE

• I CANNOT GO ANY FURTHER WITHOUT INFORMING THE READER THAT MY SEISMIC KNOWLEDGE HAS ONLY BEEN GATHERED SINCE AZF STUDY, THAT MEANS BEGIN 2009.

• PRIOR THAT DATE I ONLY KNEW SOME BASICS ABOUT THE RICHTER SCALE.

• THEREFORE MY TECHNICAL APPROACH ON THIS SUBJECT MUST BE READ WITH CARE.

• BY ENTERING THIS FIELD, LITTERED WITH LOG FORMULAS, ONE MUST ALSO BE AWARE THAT SMALL APPROXIMATIONS LEAD TO IMPORTANT CHANGES OF THE FINAL RESULT.

AZF SEISMIC ANALYSIS• THE AZF DETONATION HAS BEEN WELL RECORDED AT

LARGE DISTANCES (A DOZEN RéNaSS STATIONS AND AS MANY CEA - DASE STATIONS.

• THE AVERAGE MAGNITUDE GIVEN BY THOSE SEISMIC STATIONS IS ML = 3.3.

• ONE NAMED OMP IS VERY INTERESTING SINCE THE LOCATION IS 4190m FROM GZO.

• IT HAD A REJECTED SEISMOMETER FOR RECORDING TESTS , NOT INSTALLED PROPERLY,THE SENSOR JUST SET ON THE FLOOR OF A GROUND FLOOR OFFICE.

• IT PROVIDED EXELLENT SIGNALS.• UNLUCKYLY, THE PERSONNEL IN CHARGE WAS TOO

INCOMPETENT TO PROVIDE ACCURATE CALIBRATION OF THIS EQUIPMENT.

OMP VERTICAL SEISMIC SIGNAL

DETAIL OF FIRST P WAVE ARRIVAL,

VP = 4190m / 1.42s = 2950 m / s

AIR SLAP

V = 4190m/ (10.57+1.42)s =

349.5 m/s

ΔT = 10.57s

To

ΔT = 1.42s

OMP AIR BLAST SPEED INVESTIGATION

• WE HAVE THE MEASURED AVERAGE BLAST SPEED ARRIVING AT OMP AS 4190m / 11.99s = 349.5m/s,

• THIS BLAST SPEED MUST BE WIND CORRECTED, 7m/s*COS (150°- 93°) = + 3.8m/s => 349.5m/s + 3.8m/s = 353.3m/s, (93° GZO => OMP), • SO THE THEORETICAL BLAST SPEED IS IN FACT 353.3m/s. • THE SOUND SPEED AT 17.2°C AND 88% HYGRO IS 342.7 m/s,• THE DIFFERENCE OF THE AVERAGE BLAST SPEED TO SOUND

SPEED IS THEREFORE 353.3m/s - 342.7m/s = 10.6m/s, • THIS OVERSPEED ΔV IS RELATED TO THE SCALED DISTANCE Dr AS ΔV m/s = 1100/ Dr FOR Dr = D/W0.33 > 30, => W = (ΔV * D / 1100)3

SO W = (10.6 m/s * 4190m / 1100)3 ≈ 66000Kg TNT, ( FACTOR 1100 FOR THE GIVEN ATMOSPHERIC CONDITIONS). THIS CALCULATED CHARGE CONFIRMS THAT 60T TNT FOR THE BLAST ESTIMATION IS REASONABLE.THE EMPIRICAL SCALING LAW, THE WIND , WINDGUSTS , DOES NOT ALLOW A PRECISION BETTER THAN ± 20% .

OMP FINAL CONSIDERATIONS• AT 4190m FROM GZO,THE GEOPHONE, POSITIONED ON

THE OFFICE CONCRETE FLOOR, HAS WELL RECORDED THE SEISMIC SIGNALS, BUT THE PHASES AND AMPLITUDES ARE MOST PROBABLY BIASED.

• THE RELATIVE TIMINGS PROVIDE ACCURATE INFORMATION (BUT NO ABSOLUTE TIME REFERENCE).

• THE TIME OF ARRIVAL FOR THE BLAST IS NOT A GOOD PARAMETER FOR CHARGE ESTIMATION,

• AT OMP, A 10% CHARGE VARIATION MAKES ONLY ≈ 0.1% DIFFERENCE OF BLAST TIME ARRIVAL.

• THE REAL PARTICULE VELOCITY OF THE P WAVE IS PROBABLY IN THE RANGE 0.5 TO 1 mm/s.

• THE UNKNOWN BUILDING ATTENUATION MODIFIES THE SIGNAL AMPLITUDES AND PHASES.

SEISMIC MAGNITUDE

• THE AVERAGE SEISMIC MAGNITUDE RECORDED ML = 3.3 ,• BASED ON THIS MAGNITUDE, HOW DO WE ESTIMATE THE CHARGE W ?• IN FACT SOME STUDIES BASED ON NUCLEAR OR

CHEMICAL DETONATIONS RELATE THE MAGNITUDE TO THE CHARGE,

• THE FORMULAS ARE IN THE FORM M = K*log(W) + G WITH “K” A COEFFICIENT RANGING FROM 0.70 TO 0.85, “W” THE CHARGE AND “G” A CORRECTION FACTOR FOR

SOIL / PROPAGATION SPECIFICITIES,• THE NUCLEAR TESTS HAD AN AVERAGE MAGNITUDE OF mb = 0.85*log(W KT) + 4.2 , (+ 3.8 FOR NEVADA TESTS, DUE TO EARTH PROPAGATION PARTICULARITY).

MAGNITUDE RELATED TO CHARGE

A DERIVED FORMULA IS M ≈ 0.73*log (f*WKg) + G WE INCLUDE THE DEFICIT LINKED TO THE GROUND

COUPLING FACTOR “f “, (f ≈ 0.14 FOR ABOVE SURFACE DETONATION AND f ≈ 0.4 FOR SCALED HOB =0 AS GIVEN BY CONWEP), G is + 0.2 FOR OPTIMAL PROPAGATION BUT WE CONSIDER G=0 TO COMPENSATE THE MAGNITUDE DEFICIT FOR ALLUVIUM SOIL,

THE AZF CHARGE HAS A MUCH BETTER COUPLING FACTOR DUE TO THE CRUST AND CHARGE SHAPE

f ≈ 0.34+30% = 0.44, 30% GROUND EFFICIENCY GAINED OVER THE HEMISPHERICAL CHARGE .

USING THOSE ASSUMPTIONS WE OBTAIN : M = 0.73*log( 0,44*75000) ≈ 3.3 , EXPLAINING WHY THIS 75T

SURFACE DETONATION SETS A RECORD IN SEISMIC SIGNATURE (ACCIDENTS OR TESTS).

INVESTIGATION MAIN TESTS /

TRIALSAUDITIONS

DCCNa CHLORE INVESTIGATION

• A REASONABLE DOUBT WAS ABOUT SOME CHLORE PRODUCT, DCCNa, SKIPPED BY ERROR IN THE BLDG 221 BOX,

• THIS PRODUCT, FORMULA C3N3O3Cl2Na, HAS A VERY STRONG CHLORE SMELL,

• THE JUDGE ORDERED THE REENACTING OF THE SHOVELING OF SUCH PRODUCT,

• IT WAS FUNNY TO WITNESS HOW FAST THE ASSISTANCE MOVED FROM THE SCENE, SUFFOCATING,

• SO THE THEORY CHANGED FROM IMPORTANT QUANTITIES SHOVELED BY INADVERTANCE ,TO

A FEW KILOS OF THIS PRODUCT,• NEVERTHELESS,THE EXPERTS CONSIDERING SUCH EVENT

COULD HAVE HAPPENED, LAUNCHED A HUGE AND COSTLY INVESTIGATION BASED ON THIS REMOTE POSSIBILITY.

DCCNa CHLORE INVESTIGATION

• THEORETICALLY IT WAS PROVEN THAT DCCNa, MIXED WITH AMMONIUM NITRATES AND SOME WATER, COULD PRODUCE NCl3 , WHICH INDEED IS A PRIMARY EXPLOSIVE,

• WELL ENGINEERED TRIALS PROVED THAT SUCH PRIMARY DETONATION CAN HAPPEN, EVEN IF ONLY ONE OUT OF 20 TRIALS WAS POSITIVE!!

• IN CASE THE MAIN STOCKPILE IS VERY CLOSE TO THE “BOX “ THE SOIL CRUST CONNECTING BOTH PILES, SYMPATHETIC DETONATION COULD OCCUR,

• BUT THIS THEORY IS VERY FAR FROM THE REAL FIELD CONDITIONS , AND EVEN MORE IMPORTANT IT IS BASED ON THE UNPROVEN FACT OF DCCNA PRESENCE IN THE BOX.

DCCNa INVESTIGATION, EXPERT VERSION

INITIATOR

EAST

RELAY 2RELAY 1

MAIN STOCKPILE

WALL

10T NAA PILE

2 NAI PILES

NAI + DCCNa

WET « AN » CRUST

DRAWING FROM THE FINAL EXPERT REPORT

FORGOTTEN WALL?

DCCNa THE SOLUTION ??

• FIRST, THE PRESENCE OF CHLORE, IN SUFFICIENT QUANTITIES IN THE “BOX “ IS FAR FROM PROVEN,

• SECOND, AFTER MANY COMPLICATED CHEMICAL TRANSFORMATIONS, THE PRODUCTION OF NCL3 IN REAL CONDITIONS, COMPARED TO THE WELL ENGINEERED TRIALS, IS RATHER DOUBTFUL,

• THIRD, THE DISTANCE LAW FOR SYMPATHETIC DETONATION APPLIES BETWEEN TWO EXPLOSIVES AND NOT FOR A FERTILIZER STOCKPILE ,

• FOURTH THE REAL DISTANCE BETWEEN THE PILES, HAS BEEN MANIPULATED,

• FIFTH THE “BOX”SEPARATING WALL IS IGNORED.

ELECTRICAL TESTS AND TRIALS ,

EVIDENTLY, IN SUCH INDUSTRIAL ENVIRONMENT MANY HV TRANSFORMERS ARE INSTALLED,

• MAIN POWER IS 225KV , DOWN TO 63KV, 20KV AND 6.2KV,• EVEN IF NO ELECTRICAL CABLING IS IN BLDG 221 A HIGH GROUND POTENTIAL COULD BE A SUSPECT,• MANY TRIALS HAVE BEEN MADE, ALL NEGATIVE,• SINCE ALL ELECTRICAL CABLES, GROUNDINGS ARE

DESTROYED AT CRATER VICINITY ,THESE TESTS CAN GIVE AT BEST AN INDICATION BUT NO PROOF.

• ELECTRICAL DISTURBANCES HAVE BEEN REPORTED PRIOR To , BUT THEY COULD NOT BE TRACED,

• DUE TO THE DETONATION, NUMEROUS ELECTRICAL ANOMALIES HAVE BEEN AUTOMATICALLY RECORDED,

• BUT PRIOR To, NOTHING CONSISTANT.

BIG ELECTRICAL DISTURBANCE ? EVIDENTLY, HUGE ELECTRICAL POWER WAS AVAILABLE ON THE SITE,THE DIFFERENT LINES WERE INTERCONNECTED FOR BACK UP REASONS AND THE RESULTING NET WAS RATHER COMPLEX,• THE EXPERTS CONCLUDED THAT ELECTRICAL DISTURBANCES COULD NOT BE RESPONSIBLE FOR THE DETONATION.• CURIOUSLY, ON THE 63KV LINE CLOSE TO AZF, THE MAST TOP GROUNDING CABLE HAS BEEN REPAIRED MANY TIMES, AT SHORT DISTANCES, • THIS COULD INDICATE THAT THE ELECTRICAL ENVIRONMENT / GROUNDING AT AZF AND VICINITYWAS NOT REALLY UNDER CONTROL, BUT IS IT SUFFICIENT TO TRIGGER A DETONATION,

ELECTRICAL LINE, 63KV• ON THE 63KV LINE, 260m FROM GZO (SEE HEREAFTER) THE CABLE OF PHASE 7 HAS BEEN FOUND CUT, BOTH ENDS LYING ON THE GROUND, IN THE MIDDLE OF THE TWO SUPPORTING TOWERS,• A SHORT CIRCUIT BETWEEN PHASE 7 AND PHASE 3(SOME 2.5m ABOVE LINE 7) IS RECORDED AT 10H18:07.39s.• THE EXPERTS EXPLANATION IS THAT THE FAILURE OCCURED DUE TO A ≈ 70Kg METALIC FRAGMENT, WHICH AFTER A 11s PARABOLIC FLIGHT , HITS AT HIGH ANGLE LINE 7 AND THE UP-REBOUND LINKS PHASES 7 AND 3,• PROBLEM, NO SUCH HEAVY FRAGMENT HAS BEEN FOUND AND THIS THEORY SEEMS RATHER UNBELIEVIBLE,• NO OTHER EXPLANATION IS FOUND AND JUST ADDS TO THE NUMEROUS MYSTERIOUS FACTS.

ELECTRICAL LINES, TRANSFORMERS

T36

T0,T10

T24

T53

T23

220KV6,2KV

T xx 6,2 KV

380V, 3Φ

63KV

20KV

LA FOURGUETTE

63 KV LINE

LINE CUT

P9

P10

SEISMIC TRIALS YEAR 2004 PART 1

THE PURPOSE OF THESE TRIALS WERE:• PROVIDE THE SOIL SEISMIC CHARACTERISTICS,• DEFINE PRECISELY THE ARRIVAL TIMES FROM AZF

CRATER TO THE PLACES OF INTEREST ,• TRY TO COMPARE THE WAVES AND AMPLITUDES AT

THE SEISMIC STATIONS BETWEEN THESE TRIALS AND AZF EVENT.

CHARGES OF YIELD BETWEEN 1 AND 35Kg HAVE BEEN FIRED, CYLINDRICAL SHAPE, PLACED VERTICALLY, AT A DEPTH OF AROUND 30m.

FOR SUCH ENGINEERED TRIALS THE COUPLING FACTOR CAN BE CONSIDERED AS OPTIMAL.

SEISMIC TRIALS 2004 PART 2

ADDITIONAL TRIALS HAVE BEEN MADE WITH A FALLING WEIGHT IN THE VICINITY OF AZF CRATER:• WEIGHT 20T, HEIGHT 20m,• ENERGY E = mgh = 3.9*106J, CLOSE TO THE ENERGY OF 1 Kg TNT (4.2*106J/Kg ).• IN FACT SUCH SEISMIC SIGNATURE WAS, AT CLOSE RANGE, SIMILAR TO A 1 KG TNT COUPLED DETONATION: THE FALLING WEIGHT HAS A GOOD SEISMIC EFFICIENCY,THE ALLUVIUM SOIL CAN BE CONSIDERED AS A GOOD SEISMIC PROPAGATING MEDIA.•THE AZF SEISMIC SIGNAL CAN BE WELL SIMULATED BY ADDING UP 170 SUCH DROP TESTS,•SUPPOSING THE DROP TEST EFFICIENCY IS 95% THE SEISMIC ENERGY FOR AZF IS 0.95*170*3.9*106J= 6.3*108J• THE AZF SEISMIC EFFICIENCY IS 6.3*108 / 75000*4.2*106 = 2‰

WITNESS PERCEPTIONS

WITNESS LOCATION FUNCTION OF DEPOSITION

A curious geometrical pattern, centered on BLDG 221

63 KV line

WITNESS LOCATION / NUMBER OF EXPLOSIONS

0 DETONATION12

DISTANCE FROM CRATER METERS

NUMBER OF WITNESS, BLACK POINTS

HOW MANY EXPLOSIONS?SEISMIC RUMBLING , SHAKING

DETONATION TIME THE DETONATION TIME To, BASED ON SEISMIC Pg

WAVE ARRIVAL, ML = 3.3 , To = 10H17: 55.45s ± 0.02s. THE To BASED ON OTHER EFFECTS COULD NOT

BEEN DETERMINED WITH IDENTICAL PRECISION:• TRANSFORMER T 24 SOME 100m FROM BLDG 221

REGISTERED A FAILURE AT 10H17:55.52s , ASSUMING A BLAST ARRIVAL TIME OF 100ms WE OBTAIN To 10H17:55.42s ± 0.05s,

• AIR SLAP ARRIVAL AT MTLF STATION IS 10H21:19 THE SOUND TRAVEL TIME IS 203.6s SO To ≈ 10H17:53s,

• AIR SLAP ARRIVAL AT OMP CANNOT BE USED , NO TIME BASE FOR THE RECORDER ON TEST.

DISCOVERED ANOMALIES 1THE INVESTIGATION FOUND OUT THAT : BLDG 221 WAS NOT CONSIDERED AS A SAFETY HAZARD, NEGLECTING COMPLETELY THAT “OUT OF SPECIFICATION AN” WAS STORED THERE ! NO FIRE, SMOKE OR NOx DETECTOR WERE INSTALLED, THE FLUORESCENT LIGHTING WAS STANDARD INDUSTRY THE RECOMMENDATION OF STORING SEVERAL PILES, 50T EACH WITH A 2 m SEPARATION WERE NOT FOLLOWED, THE 60 YEARS OLD CONCRETE SLAB, WAS HEAVILY DAMAGED, THE CONCRETE EATEN AND PROGRESSIVELY REPLACED BY THE AN CRUST EMBEDED IN THE REBAR, THIS SLAB HAS NEVER BEEN REPLACED AND THE OLD POLLUTED “AN “ CRUST NEVER BEEN REMOVED, WITH THE DOORS ALWAYS OPEN, DEPENDING ON AIR HYGROMETRY, SOME WATER FORMED ON THIS CRUST SEEPING UNDERGROUND THROUGH THE DAMAGED SLAB.

DISCOVERED ANOMALIES 2 UP TO 25 SUB CONTRACTORS WERE WORKING PERMANENTLY ON THE SITE, THE SAFETY MANAGEMENT WAS THEREFORE VERY VULNERABLE ON THIS SEVESO CLASSIFIED SITE, THE MANAGEMENT LOST PROGRESSIVELY KNOWLEDGE OF THE HANDLING, STORAGE AND TRANSPORT PROCESSES. IT HAS BEEN PROVEN THAT PRODUCT FLOW WAS NOT WELL MONITORED, BIG BAGS SUCH AS DCCNa OR CYANURIC ACID WERE FOUND AT THE WRONG PLACES => DCCNa ACCIDENT THEORY, ONLY SUB CONTRACTORS WERE WORKING IN BLDG 221, WITHOUT PROOF, HEAVY CRITIC FELL RAPIDLY ON THESE SUB CONTRACTORS ,THIS, AND THE FACT THAT THE COMPANY BARELY KNEW BLDG 221 EXISTENCE, LEAD TO ACCIDENT INVESTIGATION DIFFICULTIES.

DISCOVERED ANOMALIES 3

TO MAKE THINGS A LITTLE BIT MORE COMPLICATED FOLLOWING ANOMALIES ARE WORTH MENTIONING:• 18Kg OF HEXAVALENT CHROME, DELIVERED IN AUGUST 2001, HAVE, AT AN UNKNOWN MOMENT, DISAPPEARED FROM THE AZF STORE,• AN ELECTRIC DETONATOR, TYPE DAVEY BICKFORD, HAS BEEN FOUND UNDER A METAL SHEET, AMONGST BLAST PROJECTIONS, IT BELONGS TO AZF , IT WAS IN PERFECT CONDITIONS, OBVIOUSLY DEPOSITED THERE,• AN ELECTRICAL HV POWER TRANSFORMER CLOSE TO BLDG 221 HAS BEEN REMOVED WITH CUTTING TORCHES AND CRANE , THIS UNAUTHORIZED HEAVY OPERATION WENT COMPLETELY UNNOTICED !

EXPLOSION INITIATION PROBLEM• NOBODY WAS INSIDE THIS BLDG,• 15 MINUTES PRIOR “To”, BLDG 221, SEEN FROM OUTSIDE

SEEMED NORMAL,• NO ELECTRICAL LINES IN THE BLDG, LIGHT FROM 222. HERE BELOW WHAT HAS (ALMOST) BEEN EXCLUDED:• TERRORIST ACTION,• FIRE, LIGHTNING,• METEORITE AND OTHER FALLING OBJECT,• BOMB FROM LAST WAR UNDER THE PILE,• GUIDED WEAPON IMPACT,• MAGNETIC, ELECTROMAGNETIC IMPULSE,• HIGH ELECTRICAL DISTURBANCE,• BACTERIOLOGICAL , CHEMICAL DECOMPOSITION. AN ACT OF GOD COULD NOT BEEN RULED OUT.

INVESTIGATION ANOMALIES

AND LESSONS

INVESTIGATION MAIN ANOMALIES 1OMP , SEISMIC SIGNALS , A MAJOR WITNESS IS STILL HULLED IN HEAVY FOG:• 3 DIFFERENT CALIBRATION VALUES HAVE BEEN OFFICIALLY PROVIDED SO AS 2 DIFFERENT SENSOR ORIENTATIONS, WHAT CONFIDENCE REMAINS ?• TWO SETS OF DIFFERENT DIGITAL RECORDINGS OF THESE SIGNALS WERE RELEASED, EVEN IF NOT BOTH OFFICIALLY.• THE OMP SEISMIC EQUIPMENT WAS A REJECTED GEOPHONE JUST USED TO TEST THE RECORDERS, BUT THIS REJECTED EQUIPMENT , IT SEEMS, WENT LATER IN OPERATION , NO REPAIR INFORMATION PROVIDED.• THE REJECTED EQUIPMENT WORKED CURIOUSLY WELL, NO CLUE WHY IT WAS REJECTED.

INVESTIGATION MAIN ANOMALIES 2

THE FRAGMENTS, ANOTHER MAJOR WITNESS OF THE DETONATION HAVE NOT BEEN STUDIED AT ALL.

• BASED ON BUILDING CHARACTERISTICS IT WOULD HAVE BEEN EASY TO LOCATE THE ORIGINAL LOCATION OF MOST OF THE BIG FRAGMENTS,

• BASED ON FRAGMENT DISTANCE AND EJECTION ANGLE THE DETONATED STOCKPILE COULD HAVE BEEN MODELLED AND COMPARED TO THE CRATER MODEL.

• MANY HEAVY FRAGMENTS, IN THE MASS RANGE OF 1000Kg WOULD HAVE PROVIDED THE IMPULSE ESTIMATION OF THEIR EJECTION,

• THE IMPACT CRATER OF THOSE FRAGMENTS INDICATED THEIR ARRIVAL ANGLE.

• THE FINDING OF ALL ROOF SUPPORTING COLUMNS SHOULD HAVE BEEN A PRIORITY.

POST ACCIDENT INVESTIGATION 1• THIS CASE HAS PROVEN THE UTMOST IMPORTANCE OF

RELIABLE AND PRECISE TIME BASE FOR ALL TYPE OF RECORDING EQUIPMENT,

• WITHOUT SUCH PRECISE INFORMATION IT IS QUITE IMPOSSIBLE TO HAVE AN UNCHALLENGED CHRONOLOGY OF THE DIFFERENT EVENTS,

• WITHOUT SUCH CHRONOLOGY, IT BECOMES IMPOSSIBLE TO RELATE THE EVENTS, WHICH, FOR ACCIDENTS OCCUR IN A VERY SMALL TIME GAP.

• USE RECORDERS WHICH DO NOT ERASE PRE ACCIDENT DATA DUE TO POST ACCIDENT DATA SATURATION, ELECTRICAL PRE - DATAS ARE LOST FOR AZF.

• IMMEDIATELY FIND AND SECURE ALL RECORDED DATAS OF THE EVENT ,

• IN AZF CASE, TWO IMPORTANT RECORDS HAVE BEEN DISCOVERED IN 2004 AND 2005 RESPECTIVELY.

POST ACCIDENT INVESTIGATION 2

• THE PRELIMINARY INVESTIGATION MUST QUICKLY ESTABLISH THE MOST CREDIBLE EVENT LIST AND ANALYSE IMMEDIATELY ALL DISCREPENCIES,

• AS TIME GOES, SUCH LATE ANALYSE BECOMES IMPOSSIBLE OR TOO UNRELIABLE.

• EVEN IF DIFFICULT TO ENFORCE IN SUCH CHAOTIC CONDITIONS, THE AUTHORIZED ACCESS OF THE SITE MUST BE DRASTICALLY MONITORED,

• AN OTHER LESSON, IS THE ABSOLUTE NEED OF AT LEAST ONE HIGH LEVEL PROFESSIONAL IN THE MAIN FIELD OF INVESTIGATION.

POST ACCIDENT INVESTIGATION 3• THE FINAL REPORT OF THE COURT EXPERTS MUST BE

CLEAR, CONCISE, DETAILING IN TERMS OF CERTAINITY OR PROBABILITY THE DIFFERENT EVENTS ANALYZED.

• NO NEED TO GIVE A SOLUTION BASED ON GUESSES UNLESS CLEARLY STATED SO.

• AZF FINAL REPORT IS FULL OF MISTAKES AND APPROXIMATIONS, BUT THE FINAL RESULT IS GIVEN WITH A PRECISION OF 3 DECIMALS !!

• AS USUAL, THE FACTS ARE DISTORTED TO FIT THE UNIQUE FOUND SOLUTION.

• EVIDENTLY, MISTAKES IN SUCH IMPORTANT REPORT TRIGGERS IMMEDIATE MISTRUST FOR EVEN THE BEST ANALYSED TOPIC.

• IN FACT, IN ALL SUCH CASES,THE TENDANCY IS TO SEE A CONSPIRATY INSTEAD OF SOLID INCOMPETENCE.

AZF QUIZZ

BASIC QUESTIONARY 1• WHAT IS THE CORRECT “AN “ => TNT EQUIVALENCY

FACTOR FOR AZF STOCKPILE , 0.35 , 0.4 , 0.45 , 0.5 ?• CONSIDERING THE BLAST EFFECT WHAT QUANTITY

OF TNT IS INVOLVED 40T, 60T, 80T,100T ?• SAME QUESTION FOR CRATER 40T, 60T , 80T ,100T ?• DOES THE CRATER PROFILE CORRESPOND TO AN

EAST INITIATION OF THE STOCKPILE?• IS SUCH FERTILIZER PILE ABLE TO DELIVER A ML 3.3 LOCAL MAGNITUDE?• FOR SURFACE DETONATION, ALLUVIUM SOIL ,WHAT

QUANTITY OF TNT WOULD NORMALLY BE NEEDED FOR ML 3.3 , 40T , 100T, 300T , 500T ?

BASIC QUESTIONARY 2• IN THE MORNING, UNUSUAL STRONG AMONIAC SMELL

OVER THE AREA , HAS SUCH CHEMICAL RELEASE HYDRAZINE FOR EXAMPLE, STORED / USED IN A PLANT OPPOSITE GARONNE RIVER, D = 500m,TRIGGERED THE FATAL EVENT CHAIN ?

• SOME KIND OF VERTICAL AND HORIZONTAL LASER BEAMS HAVE BEEN SEEN PRIOR THE DETONATION COULD THEY BE RELATED ?

• ELECTRICAL SHOCKS , OCCURRED PRIOR THE DETONATION, COULD A HIGH GROUND POTENTIAL TRIGGER THE DETONATION ?

• THE ALUMINIUM ROOF ,THE CONCRETE REINFORCEMENT MESH, COULD THEY HAVE PLAYED A MAJOR ROLE IN AN EVENTUAL ELECTRICAL INITIATION , AS CAPACITOR?

BASIC QUESTIONARY 3• “AN” IS VERY FLEGMATIC, THIS SEEMS TO

EXCLUDE ALL AVAILABLE INITIATION POSSIBILITIES, SO , WAS THIS “AN” STOCKPILE REALLY NORMAL?

• GREY, VERTICAL,CYLINDRICAL CLOUDS HAVE BEEN SEEN, HAVE THEY ORIGINATED A VCE (VAPOUR CLOUD EXPLOSION) ?

• COULD SUCH VCE BE RESPONSIBLE FOR THE ELECTRICAL DISTURBANCES? AZF STOCKPILE DETONATION?

• IS THE DCCNa THEORY MORE CREDIBLE THAN EXPLAINED IN THE SLIDES?

• WHAT HAS RUPTURED THE 63KV LINE AT To + 12s?

BASIC QUESTIONARY 4

• WHY IS THE FRAGMENT STUDY IMPORTANT FOR SUCH ACCIDENT INVESTIGATION?

• EXPLOSION SOUNDS HAVE BEEN HEARD AT DIFFERENT LOCATIONS 4 TO 8s PRIOR THE HUGE AZF BLAST, BUT NOT A SINGLE PROOF SUCH DETONATION / DEFLAGRATION HAS EXISTED.

• SO, HOW ACCURATE AND RELIABLE ARE WITNESSES UNDER SUCH CIRCONSTANCES?

• FINALLY, WITHOUT ANY CLUE, SHOULD A TERRORIST ACTION, EVEN LONG BEFORE To

BE RULED OUT?

ANNEXESSOME TOPICS DETAILED HERE :• CHARGE CONSIDERATIONS,• GROUND COUPLING FACTOR,• SEISMIC ENERGY,• PEAK PARTICULE VELOCITY• MAGNITUDE <= > CHARGE RELATION,• TNT CHARGE ESTIMATION FOR ACCIDENTS• AZF POSSIBLE SCENARIO,• INTERESTING ACCIDENTS OR TESTS CHART

CHARGE CONSIDERATIONS 1WE COMPARE HERE THE STANDARD REFERENCE SPHERICAL / HEMISPHERICAL CHARGE USED FOR ALL SOFTWARES / CHARTS WITH OUR SUPPOSED PARALLELIPEDIC OR CYLINDRICAL CHARGE:• FOR BLAST EFFECT,• FOR GROUND SHOCK,FOR COMPARISON WE REPRODUCE THE NEAR FIELD BLAST EFFECTS OF AN ALMOST EQUIVALENT CYLINDRICAL CHARGE.

CHARGE CONSIDERATIONS 2

THE ENERGY IMPARTED IN THE GROUND OR AIR IS LINKED TO THE CHARGE SURFACES DIRECTED TOWARD GROUND OR AIR, FOR HEMISPHERICAL WE HAVE 0.33 / 0.67, FOR AZF PILE AND CRUST 0.44/0.56 EXPLAINING THE IMPORTANT SEISMIC MAGNITUDE.

75T TNT QUIVALENT

CG 1.0mR ≈ 2.8m

R = 2.2m

CG 2.2m

CG 0.7m

CYLINDRICAL CHARGE, NEAR FIELD PRESSURES• FIGURES FOR THEORETICAL NEAR

FIELD OVERPRESSURES VERSUS AZIMUT, FOR A CYLINDRICAL CHARGE 70T TNT WITH L / D ≈ 5 ,

END INITIATED, GIVEN AT DIFFERENT DISTANCES.

• TOP FIGURE CANNOT APPLY EXACTLY TO OUR STOCKPILE, DUE TO ITS IMPORTANT DIMENSIONS.

• CYLINDRICAL (OR PARALELLIPEDIC) CHARGES GENERATE SECONDARY SHOCK WAVES SOMETIMES GREATER THAN THE INITIAL SHOCK (OFTEN IN THE LONGITUDINAL AXIS )

• FOR D > 300m PRESSURES ARE CLOSE TO HEMISPHERICAL CHARGE

Pressures in bar

Pressures in mbarBASED ON NWC TP 6382

AZF CHARGE, PRESSURE FOCUSING NORTH

155m

225m

AZF CHARGE, PRESSURE FOCUSING NORTH

• THE OVERPRESSURE FOCUSING IS OBVIOUS ON THIS VIEW NORTH OF CRATER:

AT 155 m STEEL PIPE SHOWS MAXIMUM BENDING, AT 225 m ON AXIX ,TREE TOPS CUT AT A HEIGHT OF

1,5m BUT OTHER TREES ON THE RIGHT ARE STILL STANDING.

• THE THEORETICAL FOCUSING OF A CYLINDRICAL CHARGE BECOMES NEGLIGIBLE AT SCALED DISTANCES AROUND 6 m / Kg1/3 , OR 15 ft / lb1/3.

• THE SIGNIFICANT SHARP FOCUSING AS SEEN ON THE PREVIOUS PICTURE SEEMS CURIOUS BUT AT SUCH DISTANCES WE DO NOT HAVE A POINT CHARGE SINCE

Dm < 10*Lm = 250m, Lm CYLINDER LENGTH AND THE REDUCED DISTANCE Z IS NOT 155m/600000.33 = 4.1 BUT

Z = Dm/ (W/m)0.5 = 155/(60000/25)0,5 AND Z≈ 155/50 = 3.2.

• THE GROUND COUPLING FACTOR “ f ” AS DEFINED BY CONWEP IS A FACTOR TAKING INTO ACCOUNT: THE CHARGE ENERGY PARTITIONING AIR /GROUND, THE CHARGE / GROUND EFFICIENCY FOR RADIATED SEISMIC EFFECTS,• IT IS UNKNOWN IF THIS FACTOR IS INFLUENCED BY AN UPWARD OR DOWNWARD DETONATION.• THIS FACTOR VARIES FROM 0.14 FOR ABOVE SURFACE DETONATION TO 1 FOR FULLY BURIED AND EARTH/ROCK INTIMATE CONTACT.• FOR CONWEP, ALL SEISMIC EFFECTS ARE PROPORTIONAL TO THIS FACTOR.

• WE COMPARE ALSO CONWEP TO LAMPSON COUPLING FACTOR, HIS ESTIMATION TAKES INTO ACCOUNT THE EFFECTIVENESS LOSS AT GREATER DEPTH DUE TO

SOIL DENSITY INCREASE.

GROUND COUPLING FACTOR 1

CONWEP IS THE RED FUNCTION, WE HAVE ADDED THE ESTIMATED FACTOR CURVES FOR UPWARD / DOWNWARD CHARGE INITIATION,• WE COMPARE ALSO CONWEP TO LAMPSON COUPLING FACTOR, HIS ESTIMATION TAKES INTO ACCOUNT A LOSS OF CHARGE EFFECTIVENESS AT GREATER DEPTH DUE TO SOIL DENSITY INCREASE.

GROUND COUPLING FACTOR 2

SEISMIC PEAK PARTICLE VELOCITY• WHEN SEARCHING THIS TOPIC YOU COME UP WITH AS MANY

FORMULAS AS YOU HAVE DIFFERENT STUDIES.• THE ADVANTAGE OF THIS, IS THAT YOU ARE ALMOST SURE TO FIND A FORMULA WHICH FITS YOUR DEMONSTRATION.• IN FACT ALL FORMULAS ARE OF IDENTICAL STRUCTURE, • PPV = K* Wa / Db , K IS A COEFFICIENT , SOIL AND WAVE

PROPAGATION DEPENDANT, W IS THE CHARGE, D IS THE DISTANCE , a AND b ARE EXPONENTS.

• THE CHARGE EXPONENT IS AROUND 0.7,• THE DISTANCE D EXPONENT HAS A CLOSE MATCH AT ≈ 1.7,• SOME FORMULAS COME FROM MINING TESTS WHICH IS A

DIFFERENT SOIL EXITATION AS THE ONE WE CONSIDER.• MINING USES OFTEN SEQUENCE FIRING WHICH INDUCES

WRONG RESULTS, PHASE SHIFTING OCCURS LINKED TO SEISMIC WAVE PERIOD / FIRING SEQUENCE PERIOD.

MAGNITUDE TO CHARGE FOR NUCLEAR TESTS

33,5

44,5

55,5

66,5

7

0,1 1 10 100 1000 10000

K T

mb

2,53

3,54

4,55

5,56

6,57

0,01 0,1 1 10 100 1000 10000

KT

mb

ex URSSmb = 0,85logYKT+4,2

33,5

44,5

55,5

66,5

77,5

0,1 1 10 100 1000

KT

mb

Essaisatmosphériques

USA NEVADA mb = 0.85*log(WKT) + 3.8

EX URSS mb = 0.85*log( WKT) + 4.2

FRANCE PACIFIC mb = 0.85*log(WKT) + 4.17 THE YELLOW TREND LINES

CHECK THE 0.73 (INSTEAD 0.85) LOG COEFFICIENT, ( IN FACT W EXPONENT ), COEFFICIENT 0.73 SEEMS A BETTER OVERALL FITFOR SMALLER CHARGES.

3 ATMOSPHERIC TESTS

QUICK TNT CHARGEESTIMATION IN

CASE OF AN ACCIDENT

TNT CHARGE ESTIMATIONSURFACE CHARGE ESTIMATION BY:

BROKEN WINDOWS LIMIT, Dm => WKg = Dm1,5

4 CRATER VOLUME ,Vm3 => WKg = 10*Vm3

SEISMIC MAGNITUDE , M => WKg = 101.3*M + 1

NOTE : IF CRATER VOLUME IS NOT KNOWN IT CAN BE ESTIMATED FROM THE SEISMIC MAGNITUDE BY Vm3 = 101.3*M

AZF ACCIDENT SCENARIO

BEST GUESS

BASIC FACTS THE HUGE DIFFICULTY OF THE CASE IS TO PICK UP THE FEW DIRECTLY RELEVANT FACTS AMONG THE HUNDREDS LISTED. BASED ON MANY WITNESS ACCOUNTS IT SEEMS PROVEN THAT A RELATIVE SMALL DETONATION OR DEFLAGRATION OCCURRED SOME SECONDS PRIOR MAIN DETONATION, ELECTRICAL SHOCKS ARE REPORTED PRIOR To AT BLDG 221 VICINITY. THIS FIRST EVENT DID NOT HAVE ENOUGH POWER TO BE RECORDED BY ACOUSTIC OR SEISMIC EQUIPMENT. THE INVISIBLE AGRESSION OCCURED PROBABLY UNDERGROUND TRIGGERED BY SOME GAS POCKETS (POLLUTED UNDERGROUNG ) INITIATED BY THE ELECTRICAL DEFECT.

INITIATION THEORY A DANGEROUS GAS MIX IS JUST WAITING TO BE TRIGGERED BY SOME ELECTRICAL GROUND FAILURE, WHICH SOON OCCURS.THE CONFINED VAPOR EXPLODESBREAKS EASILY A HOLE IN THE CONCRETE SLAB, AND PUSHES UPWARD THE « AN » PRILLS.THE ROOF IS EJECTED AND THE COLUMN IS SUSTAINED BY MORE COMBUSTION GASES FROM THE AGRESSED PRILLS ON COLUMN EDGE.A STRONG HISSING NOISE, HEARD IN AZF VICINITY, COULD BE LINKED TO SUCH HIGH PRESSURE ESCAPING GAS.

STEP 1

STEP 2

STEP 3

AZF DETONATION

IT IS WELL KNOWN THAT IN SUCH COLUMNS WITH PARTICLES RUBBING AGAINST EACH OTHER IMPORTANT STATIC ELECTRICITY BUILDS UP,THE ELECTRICAL DISCHARGES HEAT THE COLUMN EVEN MORE AND WITHIN 2 TO 3 SECONDS THE COLUMN DETONATES AND TRIGGERS THE STOCKPILE WHICH WAS ALREADY HEAVILY AGRESSEDFROM BOTTOM TO TOP.

STEP 4

STEP 5

SOME INTERESTING ACCIDENTS / TESTS

ANALYZED