Surface and subsurface eventsduring and subsequent to the 1994

collapse of a portion of theAkzo salt mine, Retsof, NY

A narrative

Dr. William KellyNew York State Geological Survey

Prepared for ITGAUM 2006

Involved EntitiesNYS Geological SurveyGeological consultants

NYS Department of Environmental ConservationNYS Department of Transportation

NYS Attorney GeneralNYS Emergency Management Office

Livingston County Emergency ManagementLivingston County Economic Development Office

Livingston County Health DepartmentEffected Towns

US Geological SurveyUS Army Corps of Engineers

Mine Safety and Health AdministrationAkzo-Nobel

Rochester Gas & ElectricSUC GeneseoSUNY Buffalo

Akzo-NobelRetsof minelocation

ITGAUM Mtg2006

Generalized geologic cross-sectionRetsof mine area

Vernon “B” salt

Cuylerville

2YS

11YWRt 20A

Retsof Minefootprint ~18 mi2open area ~ 10 mi2

Geneseo

Lake Ontario

2S shear circumference

11W shear circumference

Dewatering wells

Water-filled sink holes

Rt 20A bridge

Intensity (MM) distribution map3/12/94 Cuylerville event

Modified Mercalli

IV – rattle windows, doorscreaking house frame

VI – crack plaster, masonrymove heavy furniture

Cuylerville`

Rt 20A Bridge

0

1

2

3

4

5

6

1 21 41 61 81 101 121 141 161 181 201 221 241 261 281 301 321 341 361 381 401 421 441 461 481 501 521 541 561 581 601 621 641 661 681 701 721 741 761

Se

NYSGS Seismic NetFrequency of events

(events > 1sec. with assigned magnitude)

Eventsperday

3

1

2

4

5

6

March 22, 1994 – April 21, 1996

-1.7

-1.2

-0.7

-0.2

0.3

0.8

1.3

1.8

2.3

coda

mag

nitu

de, e

vent

s>1

sec.

plot

ted

1 4 5

March 22, 1994 to April 21, 1996

Magnitude - NYSGS seismic netMc=2.2(logTc)-1.70

NYSGS Seismic netMagnitude Mc=2.2(logTc)-1.70

Felt event horizon

March 22, 1994 – April 21, 19961995 1996

Cracks in snow, March 17, 1994

Disturbed pavementRt 20A bridge, west end

Immediately after 3/12/19 event

2/14/95

Frequency of events – NYSGS seismic netAKZO salt mine

“2S”

“11W”

-1.5

-1

-0.5

0

0.5

1

1.5

coda

mag

nitu

de

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31

May, 1994

Magnitude - NYSGS seismic netMc=2.2(logTc)-1.70

-1.5

-1

-0.5

0

0.5

1

1.5

coda

mag

nitu

de

22 24 26 28 30 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 1 3

Date

Magnitude - NYSGS seismic netMc=2.2(logTc)-1.70

Seismic events May, 1994

Seismic events March 22 – April 30, 1994

2S – 15’ 11W – 4’

11W – 60’

Station CUY-2 April 8, 1994

Collapse event

Associated with the formation of sinkhole over 11W

May 25, 1994 Station CUY-3

Collapse of material over 11W associated with formation of sinkhole

Water in mine, late June ‘95

Pump out attempt 4/15Restart pumping 4/20Abandon pumping 4/24

Shoreline 9/26/94

Shoreline 10/2/95

Cross section – Genesee Valley

Shale

Shale

Carbonate

Mine

H2O-bearing zonessources of inflow to mine

Wells dry within 10 daysIndustrial well 7 mi. S lost ~160’ head

Total subsidence (ft)March 1994 –July 1995

1 mile

Total subsidence (ft)April 1995

July 1996

Sterling mine

-1-2

-3

-4

-5-6-7

Subsidence over Akzo mine 7/95

Rt 20A

Cracks

Rt 20A bridge on Little Beards Creek

Cracks from 2S sinkhole formation

Cracks

Cracks E side of 2S

Rt 20A bridge, west pier

April 5, 1994

June 15, 1994

October 8, 1994

11W

Hamilton farm

Sterling B shaft

Salt pileRetsof Fuller shaft

Rt 20A

Hamilton farm

2S

11W

Collapses 2S & 11W Sept. 94

Drill casing

Rt 20A, w of bridge

Flared gas containing ~0.03% H2S

Rt 20A bridge, Feb. ‘95

Rt 20A bridge and utilities, Apr. ‘96

2S sinkhole

Rt 20A bridge restored to approximate original grade

Rt 20A Bridge and environsNovember, 1997