GENERAL37809

• Permit No: M1977215
• IBM Index Class Name: General Documents
• Doc Date: 11/24/2003
• Doc Name: Response to USFS Assessment
• From: Homestake Mining Company
• To: USFS
• Media Type: D
• Archive: No

Mr. L. Dobson
11 /14/03
Page 3 of 7
Specific comments
1. Page 9, paragraph 1- As stated in General Comment 1 above, 11 psi was chosen as an indicator
level to monitor plug performance prior to understanding what the water level was in the deep mine
pool. Based upon actual water level measurements of the deep mine pool and adit plug
performance monitoring after installation, pressure build up behind the plug is not an issue.
2, Page 12, paragraph 4 - As stated above, Homestake expected the water pressure to build up to
I 1 psi based on the geometry of the underground workings. Prior to measuring the water level in
the deep mine pool, draining of the water behind the plug was only considered an option if higher
pressures built up above 11 psi. Based on actual water level measurements of the deep mine pool,
this is no longer an issue.
3. Page 14, paragraph 2 -The original CMP culvert in the 9360 waste rock facility terminated in
Windy Gulch below the toe of the waste rock. Flow from the pipe immediately entered Windy
Gulch. It is incorrect to state in the PA that "The pipe discharges part way down the face of the
waste rock dump and cascades down the waste rock to the drainage channel below."
4. Page 14, paragraph 3 -The sprinkler system referenced in [he eastern portion of the waste rock
area was removed as part of the October 2002 reclamation activities.
5. Page 2Q paragraph 4 - As stated above in General Comment 3, Homestake disagrees with the
statement in the PA that groundwater discharge supports flow in the lower reach of Windy Gulch.
As the alluvium thins in the lower reach, flow in the alluvium appears in the channel. This flow
may be considered bank flow but should not be considered groundwater discharge.
6. Page 21, paragraph 5 - As stated above in the previous comments, the water flowing in [he
alluvium of Windy Gulch is not part of an interconnected groundwater system. Rather, it is surface
water flowing in alluvium. The quality of the surface water in Windy Gulch may have been
previously impacted by contact with the waste rock. This possibility led to the reclamation
activities completed by Homestake in November 2002 as referenced above in the General
Comments section.
7. Page 25, paragraph 1 - Is the reference to "the entire length of Willow Creek" meant to include
parts of the creek upstream of historic mining activities? Based on discussions with the WCRC, it
is Homestake's understanding chat fish are present in the upper reaches of the Willow Creek.
8. Page 25, paragraph 2 -The PA, citing [he Windy Gulch Assessment (Water Management
Consultants, 1999), states that "the upper and lower waste rock dumps release metals to surface
water." In fact, the referenced report states that the "variations in water qualit~mav result from
exposure of Windy Gulch water to naturally mineralized rock, waste dump material, or both."
9. Page 29, paragraph 2 - As described below (see paragraph 3 regarding Comments on
Recommendations in the PA), tracer samples were taken much more frequently than referenced in
the PA.
10. Page 30, paragraph 4 -Referencing a personal communication with Les Dobson, On-Scene
Coordinator, Rio Grande National Forest dated October 4, 2002, the PA states that the Bassett well
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