1992-06-15_REVISION - M1988112 ‎(3)‎

• Permit No: M1988112
• IBM Index Class Name: Revision
• Doc Date: 6/15/1992
• Doc Name: SAN LUIS PROJECT PN M-88-112 TR 8 ADEQUACY
• From: MLRD
• To: LARRY OEHLER
• Type & Sequence: TR8
• Media Type: D
• Archive: No

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~ STAT~OF COLORADO
MINED LAND RECLAMATION DIVISION
Department of Natural Resources
1313 Sherman St., Roam 215
Denver, CO 60203
303 866-3567
rnx.303 632-8106
DATE: June 15, 1992
T0: Larry Oehler
FROM: James Stevens ~~~
OF CplOq
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Roy Romer,
Governor
Michael B. Long,
Division Director
RE: San Luis Project (Permit M-88-I12) Technical Revision No. 8 Adequacy
I have reviewed proposed Technical Revision No. 8 for adequacy of the proposed
program together with locations, depths, and construction of the additional
monitoring wells. Protocols related to actual sampling of the wells are
assumed covered under TR-6.
As regards adequacy of the program, the configuration of the
potentio-metric surface in the area and likely direction of ground water
flow are essentially unknown. A considerable part of the value of the
proposed wells is to provide data to help resolve this problem. The
hydrologic situation that may be revealed by the new data, however, could
show that Well M-9 and proposed M-13 and M-14 do not in themselves
comprise a practical monitoring system for the containment pond and
treatment facility. Given the locations proposed for Wells M-13 and
M-14, should M-9 and either of the new wells have essentially the same
static head, neither might be expected to readily capture timely evidence
of a leak from the containment pond.
The operator should commit to a reevaluation of the proposed monitoring
network following drilling, data gathering, etc. and to add additional
well locations should the existing network be determined to be inadequate.
2. As for the current locations of the wells relative to the collection
pond, tailings facility and one another, the proposed network does not
appear to provide the best expectation of intercepting evidence of a
containment leak from the pond and facility. If ground water flow in the
area has a strong E to W component as is claimed, the breadth of
potential coverage by M-1 is small as a result of its being located so
close to the pond and so near a line between M-9 and the tailings
facility. On the other hand, M-14 would appear to be too far from M-9
and too far southeast of the pond to be effective in monitoring for leaks
from the pond, even counting on some dispersal.
Since the location of Well M-9 is fixed, M-13 and M-14 should be
relocated to provide greater breadth of coverage for east to west flow as
well as to provide an apparent ability, comparable to that of M-9, to
monitor for containment leaks from the pond and/or tailings facility.