1999-08-23_HYDROLOGY - M1999051

• Permit No: M1999051
• IBM Index Class Name: HYDROLOGY
• Doc Date: 8/23/1999
• Doc Name: Surface & Ground Water Monitoring Plan
• From: TRC Hydro-Geo Consultants
• To: DRMS
• Media Type: D
• Archive: No

August 1999
\99,2057\205/fin.,t
TABLE 1
RISK ASSESSMENT SUMMARY
Process Plant:
Spills - Mining Solutions, dry
product, or chemical reagents from
process system
Dusting of Dry Product
Transportation accidents of dry
product or reagents on access roads,
the well field and plant site
1) Loss of containment due to upset conditions
Subsidence - Negligible Hazard
Groundwater - Negligible Hazard (alluvial well)
Soil - Very Low Hazard
Surface Water - Negligible Hazard
1) Discharge of product to the air from the dryer
baghouse and the truck loadout area
Subsidence - Negligible Hazard
Groundwater - Negligible Hazard (alluvial well)
Soil - Negligible Hazard
Surface Water - Negligible Hazard
1) Loss of containment and spilling of liquids or
solids. Solids include sodium bicarbonate and
drilling mud bentonite or cement. Liquids
include anti - scalent reagents, fuels, and lab
reagents.
Subsidence - Negligible Hazard
Groundwater - Negligible Hazard (alluvial well)
Soil - Low to High Hazard
Surface Water - Negligible Hazard
Initiating events and likelihood: Very low likelihood due to access road layout, enforcement of posted speed limits,
and proposed road maintenance.
Magnitude of exposure: Negligible to high depending on the nature of the materials spilled. A spill of sodium
bicarbonate solids would be negligible due to lack of mobility and ease of clean up. A spill of desiel may represent a
high magnitude exposure.
Duration of exposure: Very low due to immediate recognition of the release allowing a response.
Pathways: Medium risk due to the potential for overland flow of the liquids.
Environment at risk: Soils and vegetation along access roads.
Initiating events and likelihood: Medium likelihood, failures have occurried at other similar facilities.
Magnitude of exposure: Negligible risk due to 6 inch high curbing within the plant with a gravity flow connect to
the 3 acre pond. This would allow complete containment of all process solutions stored in the tanks and vessels in
the plant.
Duration of exposure: Negligible exposure due to complete containment.
Pathways: Negligible exposure due to complete containment in the plant. Outside the plant storm water controls will
prevent flow from discharging outside the disturbed area.
Environment at risk: Topsoil will be removed from the plant area and stockpiled in a safe location for reclamation
outside the storm water controls. The only environment at risk is the foundation material within the plant complex.
Initiating events and likelihood: Medium likelihood due to occurrences at similar facilities.
Magnitude of exposure: Negligible due to operational controls at the baghouse and minimum truck containment
requirements at the load out area.
Duration of exposure: Negligible risk due to life of the facility is too short to allow build of dusting to levels of
concern.
Pathways: Medium to high due to product reaching soil and water depending on wind conditions and direction.
Environment at risk: Topsoil will be removed from the plant area and stockpiled for reclamation outside the storm
water controls. The only environment at risk is the foundation material within the plant complex.
Low consequences due,to low potential hazard to soils and medium likelihood of
occurrence. The magnitude, duration, and pathway for exposure is negligible and
the environment at risk is within the industrial disturbance area.
Negligible consequences due to negligible potential hazard to soils nd water. The
environment at risk is within the industrial disturbance area.
High consequences depending upon the nature of the spill and locat
on.
Negligible risk even with low soil hazard and medium
likelihood, due to the environment at risk being in the
industrial disturbance, and negligible exposure risk due to the
negligible magnitude, duration, and pathway for exposure.
Negligible risk even with medium likelihood due to the
negligible hazard and the environment at risk being in the
industrial disturbance.
Very low risk due to very low likelihood of occurrence.
Recommended Mitigation: Emergency Spill Response Plan;
Employee Training Program; Well Defined Action Levels for
Agency Reporting and Remediation; Employee Environmental
Protection Incentive Program; Traffic Control Signs; Road
Winter Maintenance; and Speed Limit Enforcement
Footnotes to Table 1: Risk Assessment Components:
Potential Failure Mechanisms: All identified potential mechanisms are included, regardless of likelihood of occurrence Hazard Assessment: An assessment of "what can happen ?" ranked according to risk to the environment (see Table 2)
Exposure Assessment: Assessment of the likelihood and extent of any exposure.
Consequence Assessment: An evaluation of the consequence of any exposure, regardless of how likely it is.
Risk Characterization: An evaluation of the overall risk to the environment of the identified failure mechanism, based on the evaluation of hazard, exposure and consequence.
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Golder Associates
993 -2057