1985-12-22_HYDROLOGY - M1984049

• Permit No: M1984049
• IBM Index Class Name: Hydrology
• Doc Date: 12/22/1985
• Doc Name: HYDROLOGIC EVALUATION PRIDE OF THE WEST TAILINGS POND
• Media Type: D
• Archive: No

of standards, the deadline for obtaining Group I permits has
• been postponed until December 31, 1987. (Federal Register,
Vol 50, No 168, pp 35200-35203, Aug 29, 1985.)
Whichever course of action is taken with respect to the
current seepage south of the old pond, the seepage pond dif;e
must be repaired as well as the west dike of the Phase III &
IV Er.pansion ponds. As the area south of the old pond has
wetlands characteristics and the Animas River seasonally
flows into the breached Phase IV Er.pansion pond, a Corps of
Engineers Dredge and Fill Permit (404 Permit) will probably
be required prior to initiating these repairs. The permit
application fee is X100 and the term is normally 5 Years
subject to renewal.
Any e>;pansion of the surface area of the er.isting ponds,
particularly to the south of the old pond, might also
require a 404 permit; however, this is a "grey area" and
discussion with the Corps of Engineers should be held prior
to undertaleing any construction.
MONITORING PROGRAM
The monitoring program is complicated by the already
contaminated condition of the ground water under and
adjacent to the tailings pond, requiring sufficient sampling
• to demonstrate that it was the result of previous
operations. The construction of the interceptor drain
imposes a monitoring requirement to clarify its status as a
diversion of noncontact water. The monitoring program
discussed in this section addresses these issues. The
program also assumes that recommendations as to the repair
of the breached dikes, the routing of excess water from the
decant pond and the utilization of the Phase IV Er,pansion
pond as an emergency overflow impoundment would have been
implemented.
The recommended initial monitoring program consists of
baseline sampling at 9 surface sites and 11 subsurface sites
(refer to Figure No. 15 and Table No. 10.). In addition,
water levels should be measured at all subsurface sites and
at measuring stations installed in the decant and seepage
ponds (sites 208 and 25 on Figure No. 15). There are three
additional subsurface sites: observation wells P-2, P-3 and
P-4 (sites 18, 19 & 32) located on the di4;e of the new pond.
Only water level measurements need be taken at these sites.
While the number of ground water sampling sites may seem
excessive, it must be realized that the ground water under
and adjacent to the ponds is highly contaminated at this
time and it is critical to Sultan Mountain Mine's interest
• -20-