GENERAL36924

• Permit No: M1983194
• IBM Index Class Name: General Documents
• Doc Date: 9/26/1986
• From: EPA
• To: BLM
• Media Type: D
• Archive: No

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p. 2-4 Solid removzil from the evaporation ponds could risk puncture of the
20 mil I{ypalon liner. What method will be used to remove solids to
assure protection of the liner's integrity?
p. 2-8 The use of former production wells as monitoring wells appears
practical and could be effective. The EIS should further describe
'how this will be done. EPA suggests that consideration be given to
using these wells to monitor the lower aquifer and possibly within
the solution cavities themselves. There needs to be further
indication of the method proposed for monitoring the integrity of
the mud between the 12 1/4 inch borehole and the 8 5/8 inch casing.
The document: indicates that the applicant would report water quality
monitoring on a yearly basis to EPA. EPA regulations for injection
for the purpose of mineral extraction (class III wells) require
reporting on a quarterly basis [40 CFR 146.33 (c )].
p. 2-8 The applicant proposes to assure mechanical integrity of the
injection wells by pressuring up the annular space between the 8-5/8
inch casing and the 5-1/2 inch production pipe, using air. The
pressure will be maintained at 800 psi gauge. If the pressure drops
below 700 ps.i, the well will be taken out of service. The proposed
plan may not: be adequate to assure that brine will not move into the
annular space. Assuming that the brine has a density of 1.2, the
production well will have a pressure of about 1000 psi at the base
of the 1900 foot casing. This would allow brine to extend into the
annular space about 375 feet. This point is above the B-Groove. If
the air pressure at the surface dropped to 700 psi, the brine column
would extend up the annular space to a point above the A-Groove.
p. 2-8 The section on the applicant's monitoring for mechanical intergrity
of the wells does not address potential fluid movement through
channels adjacent to the well bore. Such a determination must be
made, according to UIC regulations, prior to commencement of
injection. Two methods, which are approved of by EPA under the UIC
program, are noise logs and temperature logs [40 CFR 146.9(3)(c)].
p. 2-8 Additional details are needed on the multiple point borehole
extensometer design and installation. Why are surface monuments
installed to check for subsidence but not within first 1300 feet of
the surface? The subsidence monitoring program may not accomplish
its objective of determining the extent of rock fracturing (and
hence aquifer interconnection) between the solution cavities and the
surface unless additional monuments are established.
p. 2-9 How will the applicant assure and monitor the rib pillar dimension
of 20 feet? Strength tests have been run on the nahcolite material
and should be summarized here.