_REVISION - M1988112 ‎(2)‎

• Permit No: M1988112
• IBM Index Class Name: Revision
• Doc Name: TAILINGS PH ADJUSTMENT SYSTEM OPERATIONS REVIEW
• Type & Sequence: TR5
• Media Type: D
• Archive: No

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Fume Scrubber Recirculation Pump (04-PP-22) ~,,,-• ~~ _,
N a
The Sulfuric Acid Metering Pump stops and the pH in th~pH
1 Adjustment Tank increases, preventing further generation of
HCN. Stopping of air flow from the blower prevents further
stripping of HCN from the slurry. The agitator continues to n~~''
run to maintain suspension of the solids. Although no hazard _,W,_,
is created, continued operation results in discharge to the ~~
tailing impoundment of slurry containing higher than normall^~=
1 levels of cyanide.
Scrubber Extraction Fan (04-FA-OS)
The Sulfuric Acid Metering Pump and pH Adjustment Blower
stop. The pH increases, preventing further generation of ~~„_
HCN. Stoppage of the blower prevents further stripping of ~
HCN. The agitator continues to run to prevent settling ofn~f~
solids in the tank. The situation does not create a hazard. oz
Continued operation will result in discharge to the tailings °~""~
impoundment of slurry containing higher than normal levels
of cyanide.
Sodium Hydroxide Metering Pumps (06-PP-35)
The Sulfuric Acid Metering pump stops, interrupting the flow
of acid to the pH Adjustment Tank. The slurry pH increases
and HCN evolution stops. The scrubber continues to operate, 5°`'"~
to absorb residual HCN. Under normal conditiohs, there is H,{-c
sufficient free NaOH in the circulating scrubber solution us
to absorb this residual HCN. The agitator continues to run ~h„ ,
to maintain suspension of the solids. Continued operation
results in discharge to the tailings impoundme t of slurry
containing higher than normal levels of cyanid .
Sulfuric Acid Metering Pump (06-PP-32)
The flow of sulfuric acid stops and the pH in the pH
Adjustment Tank increases. HCN evolution ceaseffi• The blower Su v~
shuts down, stopping further stripping of HCN. The agitator f
continues to run to maintain suspension of solids. "'
Continued operation results in discharge to ~he tailings ~ 5
impoundment of slurry containing higher than ormal levels g,bv~~
of cyanide.

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