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Attachment -A

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FMC Corporation
Lithium Division
Highway 274 Tryon School Road
Box 795
Bessemer City North Carolina 28016
704 868 5300 Fax [phone]
4FMC
February 13, 1992
Mr. Tracy E. Davis, E.I.T.
Mining Specialist
Land Quality Section
State of North Carolina
Department of Environment,
Health and Natural Resources
Division of Land Resources
Raleigh, NC
Dear Mr. Davis:
Enclosed is the report covering the fly -rock incident
experienced by the FMC Lithium Division mine operations at 3:31
P.M. on February 12, 1992.
This incident was reported to Mr. Wes Webb in your Mooresville
office, as well as to you directly, the sate udcaty.
Two members of your Mooresville office, Mr. Brian North and Ms.
Daphne Cartner, conducted an investigation the morning of
February 13.
I look forward to meeting with you to review the cause of the
incident and future plans for prevention on Monday, February 17,
at 9:00 am.
Tay.Ak"
Sincerely %
ames B. Holman
Manager, Mine -Mill

FLY -ROCK INCIDENT, FEBRUARY 12, 1992
NOTE: THE FOLLOWING IS DATA CONCERNING THE FLY -ROCK INCIDENT
AT FMC LITHIUM DIVISION MINE AT 3:31 PM ON FEBRUARY 12, 1992.
Fly -rock:
As indicated on the attached map, fly -rock consisting of one
rock about fist size and another about 1/3 fist size was
reported landing on the Everette Eaker property. The Eaker
property is located adjacent to the pit perimeter. The
fly -rock landed approximately 1,125 ft. from the face of the
shot, or 100 feet beyond the guarded area.
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The shot pattern was based on a 14 ft. spacing and a 12 ft.
burden. Twenty-six of the thirty one holes were 6-1/2 inch
diameter. Five of the holes were 4--1/2 inch diameter. The
surface elevation of the shot varied from 750 to 744. The
floor elevation of the shot was 720. Holes were drilled from
27 to 33 feet deep, which included 4 ft. of sub -drilling.
(See attachment A)
Explosives:
Explosives used in the shot were ammonium nitrate and one
pound cast boosters. The initiation system used was the
non -electric Ensign Buckford E-Z det and Nonel system. There
were 8,180 pounds of Ammonium Nitrate and 31 pounds of cast
boosters used in the shot. As indicated by the attached
table, (Attachment B) the maximum explosive used in a single
hole was 318 pounds and there was a maximum of two holes per
delay, therefore, the maximum pounds per delay was 636
pounds.
Seismograph:
The seismograph was located along side of Concord Church
Road, approximately 1,000 ft. from the entrance to Concord
Church. As indicated by the enclosed reading, (attachment C)
the RPPV or vibration measurement was .01 or 1% of the
allowable one inch per second. Our decibel reading was 120db
and the allowable is 128db. The seismic unit was located
approximately 2,100 ft. soutl-least of the s hot.
Geology:
The shot in question consisted of three distinct rock .types:
mica pegmatite, amphibolite, and a biotite schist. The mica
pegmatite formed a 2 to 4 foot dike which ran parallel to the
blast face. The mica pegmatite is a very dense and a very
competent rock. The mica schist is a very incompetent
fractured rock and was found occurring on both sides of the
mica pegmatite and in the joints formed in the amphibolite.
The amphibolite, a dense, highly jointed and fractured rock,
was the bulk of the rock in the shot.

conclusion:
The fly -rock came from the open face on the South East end of
the shot. The fractured amphibolite allowed for the high
pressure gases created during the explosion to escape through
the fractures, thus creating the fly -rock. Even though the
L G sAA i vn-a astemmirlg r i d
standard precautionary measure of a.. A1* _
feet vs. a normal 8 feet or a 33% increase) was held along
the open face, poor geologic conditions counteracted the
usual reduction in column load.
Future Plans:
In areas as described above, the blast holes on the open
faces will have additional stemming. Even though the normal
standard has each drill hole surveyed and placed in a
predetermined manner to allow for sufficient burdens to
prevent fly -rock, the additional stemming will be done. This
will create an increase in large boulders. In an effort to
minimize this effect, a d-couolin of the upper portion of
the hole can be utilized by using a smaller diameter
explosive. Both methods will be used and will eliminate
fly -rock.

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%3HAKETi;EI_E CALTePATEU ► N _I1 Jul 1, /*91
BY = PHILIP F BERGER k'n Ac;=OCIATE'i;- INC.
EOX 779, IxIHRRENDALE- PA. i5095
'=:T SAFEGUARD F:FTLp1Tr Ut•IT T j.00s30
FEE! 12,,92 :51 : 54 : ��I:_:
I NSTF:UMEt-IT # SSIJ 1581
EVENT # 195
COPY # 1
CLIENT:FMC LITHIUM
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S:_U Li CATT_EIN:GPHOUSE
D I STANCE TO E:LA:::T < i I >=-00
OPERATOR : DWS
SEI S TRIG LVL ( iPs ) : . 0?
SOLND TRIG LEVEL (dB,-- 110
PEGUR€J TIME (sec): 15
FEE 12x92 15 : 54 : GIs _,
L T
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PF'V(i rlxs } «. o 1 . 00
. ►l I
PC(in) 0.00002
0.00002
F rlg(hz) 57.0
57.0
F:PF'V(in/s) 0.01
PEAK SOUND 12-0 de 0.0 B LS. i
Psi
AxD CAL I BRATE'G OK � n:
CALIERATION GRAPH
TIME
r= .384 sec/in
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SHAKETAeLE CAL I L PATEU ON JUN l a-V91
SY PH I L I P R E-EF:rEF: r A'SISQ I MTESINC.
BOX ? 79 . WARRENDALE - Phi. 15095
TEL : 41 _-776— 600
SCH,NNINQ Attachment - C