INSPEC41898

• Permit No: M1977215
• IBM Index Class Name: Inspection
• Doc Date: 11/1/2001
• Doc Name: MINERALS PROGRAM INSPECTION REPORT
• Inspection Date: 10/19/2001
• Media Type: D
• Archive: No

• (Page ZI •
MINE ID k OR PROSPECTING ID li M-1977-215
INSPECTION DATE 10-19-2001 INSPECTOR'S INITIALS SSS, RCO. ALA
This was a routine inspection conducted as part of DMG's monitoring program for permitted mines in Colorado. Bob
Oswald from the DMG Durango Field Office attended the inspection in anticipation of becoming the lead inspector on this
site in the future. AI Amundson, an engineer from DMG's Denver Office attended the inspection to become familiar with
the site in anticipation of providing support for future permit revisions that may require engineering evaluations.
The two-year water monitoring and tracer detection program implemented to assess the success of the portal seal was
completed in September. DMG is waiting on the final report for the September monitoring event. Homestake is now
required to place charcoal absorption packets in each of the tracer detection points and leave them for collection and
analysis at a future date to be specified by DMG. Reports indicated that no tracer was detected during the monitoring
period which supports the position that water impounded behind the 9360 portal seal, which was injected with the
flourescein dye tracer, remains as groundwater and does not express itself in Windy Gulch surface flows. The infiltration
trench and standpipes were abandoned last year and had not received any flow from the 9360 adit since installation of
the plug. The two piezometers installed to monitor flows into the waste rock pile from the infiltration trench have reportedly
been dry for the duration of the portal seal monitoring. Therefore, the trench inlet, standpipes, and the two piezometers
do not need to be included in the list of points where the final charcoal packet placement (described above) will occur.
With completion of the monitoring period, Homestake has indicated a desire to completely backfill the adit out by the seal.
DMG recommended that the portal backfill material be comprised of porous material such as gravel so any groundwater
passing into the adit can move through and infiltrate into the adit floor. It was discussed that a stem wall of bentonite
installed toward the portal may increase retention of any "flow through" water to aid the infiltration. The full backfill design
is proposed by Homestake to prevent future expression of subsidence on the surface above the adit where overburden
thickness decreases near the portal.
The 9700 level portal was re-opened to provide ventilation for the 9360 adit rehabilitation in 1998. Re-closure of this portal
has created a steep slope condition above a bench of material that was used to close the portal. Homestake will need to
rework this area to create a stable, less-steep slope and possibly buttress the toe of the slope when finished.
The USFS has apparently given authorization for installation of a bypass for the gulch flows crossing through the 9700 level
waste rock dump, Now that this authorization has been secured, DMG is requiring that installation of this bypass be
completed next field season. Permitting for this bypass will need to be submitted to DMG no later than January 31, 2002
and must contain a commitment to complete installation of the bypass as early as possible in the 2002 field season.
A reinforced concrete pad approximately 15 feet by 40 feet by 1 foot thick is located on the 9700 level bench, partially
hidden by a veneer of talus rock. The original purpose of this pad was not determined during the inspection. Homestake
will need to determine if this pad was part of their operation and, if so, bury it adequately or break it up and properly
dispose of it.
Weed control on the site began several years ago and has only been moderately effective. It appears that a more
aggressive control program may be necessary. Homestake will need to submit a description of the current weed control
efforts being implemented and upon DMG review, may be required to submit a technical revision addressing a more
aggressive plan. A fall 2001 application of the herbicide currently being used by Homestake is highly recommended so the
herbicide is drawn into the root system of the thistle.
Revegetation efforts on the various areas of the site have been fairly successful. However, numerous areas devoid of
vegetation exist on both tailing pond surfaces, on the 9360 waste rock dump, and on various areas around these structures.
Revegetation efforts on the lower tailings pond appear to have been improved in the area where borrow material was placed
and the area reseeded in 1999. The borrow areas on the south side of this pond appear to be revegetating well. The
borrow area on the north side of the pond appears to be dominated by sterile, coarse sands and gravels and is almost
completely devoid of vegetation, except where some soils remain around the perimeter and on the stormwater diversion
ditch. Homestake will need to take measures to establish acceptable vegetation on these bare areas. Measures may
include introduction of some organics or fertile soils into these bare areas, application of fertilizer or soil amendments,
geotextile installation, eic. Depending on the plan of operations proposed by Homestake to remedy this problem, a revision
to the permit may be required. DMG highly recommends that revegetation efforts for these bare areas be performed this