2009-12-22_REPORT - M1977004

• Permit No: M1977004
• IBM Index Class Name: REPORT
• Doc Date: 12/22/2009
• Doc Name: 2009 Annual Geotechnical Report
• From: Homestake
• To: DRMS
• Email Name: RCO
• Media Type: D
• Archive: No

H ( /M�E�TAIi.E
GRANTS NM OFFICE
Alan D. Cox
Project Manager - Pitch
December 14, 2009
Mr. Bob Oswald
Colorado Department of Natural Resources ''
Division of Minerals and Geology ct
691 CR 233, Suite A -2
Durango, CO 81301 d Z'0
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RE: HOMESTAKE PITCH RECLAMATION PROJECT ,t�;�? oiR� C%
2009 ANNUAL GEOTECHNICAL REPORT (M- 1977 -0041 'Rav Me
Dear Mr. Oswald:
Attached please find the 2009 Geotechnical Report for the waste rock management areas at the
Hornestake Pitch Reclamation Project. The waste rock dumps were inspected monthly in 2009,
except when winter conditions prohibited access, in accordance - with the recommended monitoring
program. The history of the rock dumps has been provided in previous annual reports and is not
repeated in this discussion. A site map with piezometer locations is provided as Figure 1.
Detailed analysis and presentation of the 2009 data from all piezometers are provided in the
following pages.
The visual inspections conducted in 2009 indicate stable conditions for the Indian Creek and Tie
Camp Creek waste rock dumps. The water levels in the waste rock dump piezometers in 2009
continued to show seasonal fluctuations similar to those observed in the past three years. A chart
with 2009 data is provided as Figure 2 and a chart with piezometers water levels monitoring since
1996 provided as Figure 3. The Y -axis on these plots is labeled as depth to water from ground
surface. Please note that prior to October 2001 data was not obtained from Piezometer IC10600 due
to the presence of a gravel obstruction that blocked the passage of the piezometer. In 2007, the
local elk herd destroyed the stand -pipe casing in Piezometer IC 10370 and consequently caused the
Upper part of the borehole soil to collapse into the piezometer casing. This resulted in
approximately six feet of rock debris being introduced into the bottom of the piezometer,
rendering it non - functional. In the fall of 2009 we were able to clear the rock from the bottom of the
casing by flushing with high pressure water. This allowed us to remedy the problem and to begin
using the Piezometer IC 10370 as part of the monitoring system with measurements taken the last
three months of the year. Piezometer IC10300 was also flushed in 2009 to remove a buildup of silt
in the casing. In 2010 we plan to pressure wash other piezometers in an attempt to wash out some
of the silt built up in the piezometers over the past 20 years.
Thank you for your time and attention on this matter. If you have questions, please feel free to
contact me in the Grants NM office (505) 287 -4456 x25 or via cell phone at (505) 400 -2794.
Sincerely,
Alan D. Cox Wr. 2 4 2009
Project Manager - Pitch Reclamation Project Uivre(u„ or Reelarnasoft,
cc: Rocky Chase - Barrick Management Corp. Mining and Safety
Vern Kelso - Homestake Mining Company - Sargents
Phillip De Dycker - ARCADIS -US, Inc.
HOMESTAKE MINING COMPANY OF CALIFORNIA O P.O. BOX 98, GRANTS, NM 87020
TELE: (505) 2B7 - 4456 O• FAX: [phone]