PERMFILE54123

• Permit No: M1999002
• IBM Index Class Name: Permit File
• Doc Date: 6/18/1999
• Doc Name: OBJECTORS EXHIBITS
• Media Type: D
• Archive: No

Absence of injec ~ ,the activity regulated by the federal C program, is the reason the EPA
did not require a Class I~ermit for Tully Valley in the mid-19~.
'Simulated kori4oiua! drilling.'=-The modem technique of horizontal drilling for salt cavem development
was first used in New fork in 1989, and three operators have used this method to date. However,
Solvay Process Company attempted an experimental cavem development method in the late 1920's that
can be likened to "simulated horizontal drilling."
Historical company engineering reports describe an investigation conducted in 1926 into the
feasibility of sinking a shaft to the base of salt and mining an 800-foot long tunnel along the bottom salt
bed. Fresh water would then be introduced through the shaft, with brine withdrawn from a well drilled
to intercept the other end of the tunnel (see Figure 6). The proposal for a conventionally mined shaft
and tunnel was ultimately rejected because of the high projected cost and because of uncertainty about
the regularity of the base of the salt (Shaffer, 1984).
The company in 1927 and 1928 drilled 12 closely spaced wells to the lower salt in an attempt
to simulate the tunnel proposal. The plan was to operate the wells as single-well cavems until the}
connected to form a horizontal channel in the lower salt (see Figure 7}. Once the channel formed, fresh
water .vould be injected downdip and brine withdrawn updip. However, this experiment included no
mechanism (such as roof padding) to leave salt in the channel roof; frequent caving was the result. Lon•
production capacity and the cost of repeated u•orkovers associated with the caving eventually led to
abandonment of this well group, but not before creation of a broad, flat cavity with an inadequately
supported roof (Larkin, 1950; Solvay Process Division, 1960).
The group of wells used for the tunnel simulation was also the first group of wells where aquifer
waters were intentionally ailou~ed to flood the salt cavem through uncased wellbores in the early 1930's.
Thus began wild brining, as previously discussed,
Impacts of Solution 1ltining in Tully Valley
a
Use of the three innovative cavem development methods described above a)1 contributed to
significant general ground subsidence, sinkholes, and groundwater impacts. The company's historical
reports indicate that water or brine of unknown saturation was escaping the system of interconnected
wells and cavems by 1900. Shearing of wells by rock movements associated with subsidence was
recognized as early as ] 928 (Solvay Process Division, 1960). Seven sinkholes formed between 1949 and
]950. The company reportedly repaired a county highway damaged by subsidence in the mid-1960's.
Tully (1985) documented increased groundwater recharge through subsidence-induced fractures.
Although the results have been inconclusive, many researchers have investigated the possibility of a
cause-and-effect relationship betrti•een brine field operations and the unique mudboil phenomenon norh
of the brine field (Kappcl, et al, ] 996)
It is important to understand that the known and hypothesized impacts of solution mining in Tully
Valley are not attributable to the mere act of salt extraction itself, but to the uncontrolled methods by
wf;ich such a vast quantity of salt was removed. The estimated extraction ratio of 64°o to 75% (Shaffer,
1954) is much greater than the 10% to 15% ratio estimated for modem solution mining operations to
t\ew York. Because the point of solunoning was usually unknown, expansive unsupported roof spars
were created. H~~drologic impacts of solution mining in Tully Valley have resulted from the introduction
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