2010-07-16_REPORT - C1981010

• Permit No: C1981010
• IBM Index Class Name: Report
• Doc Date: 7/16/2010
• Doc Name: Semi-Annual Geotechnical Monitoring Report Review‎(March 2010)‎
• From: DRMS
• To: Trapper Mining Inc
• Permit Index Doc Type: Stability Report
• Email Name: RDZ
• Media Type: D
• Archive: No

STATE OF COLORADO
DIVISION OF RECLAMATION, MINING AND SAFETY
Department of Natural Resources
1313 Sherman St., Room 215
Denver, Colorado 80203
Phone: [phone]
FAX: [phone]
July 16, 2010
James Mattern
Trapper Mining, Inc.
P.O. Box 187
Craig, CO 81626
RE: Trapper Mining, Inc., Permit C-81-010
Semi-annual Geotechnical Monitoring Report (March 2010)
Dear Mr. Mattem:
COLORADO.
DIVISION OF
RECLAMATION
MINING
- St-
SAFETY
Bill Ritter, Jr.
Governor
Mike King
Executive Director
Loretta E. Pineda
Director
The Colorado Division of Reclamation, Mining, and Safety (Division) has reviewed the Geotechnical
Monitoring Report (GMR) for the Trapper Mine that is dated March 31, 2010. It was received by the Division
on April 5, 2010. This GMR includes a change in monitoring methods from those historically utilized.
Revisions to the Ground Control Plan were developed in consultation with the Mine Safety and Health
Administration (MSHA), and officially incorporated into the permit with TR-106.
The Division has the following comments and requests in regard to the geotechnical monitoring system at
Trapper Mine and the March 2010 GMR.
According to the last paragraph on 3-27a of the permit document, three GPS stations were constructed in the
slide zone, and a fourth station was located outside the slide area to act as a reference and repeater station.
Station descriptions at the top of page 3-27aa indicate that Station 2 was not equipped with GPS, implying that it
is this station that lies outside the slide zone. However, Figure 3.3.3-1 seems to indicate that it is Station 3, not
Station 2, that lies outside the slide zone.
Please compare the text on pages 3-27a and 3-27aa with station locations as illustrated on Figure 3.3.3-1 and
revise, if necessary.
For each of the four new inclinometers, two readings are reported.
Please provide a brief description of the inclinometer installations and significance of the two separate
readings.
For piezometers installed in Stations 1, 2, and 3, the deeper sensor exhibits the greater piezometric pressure. At
Station 4, the L sensor (at a depth of 81.8 feet) shows 17 to 18 psi while the LM sensor (145.9-foot depth) reads
approximately 0 psi.
Please review the data for the LM sensor at Station 4 and determine if the zero reading is an accurate
depiction of conditions at that location. If it is accurate, please explain the zero psi reading.
Office of Office of
Mined Land Reclamation Denver • Grand )unction • Durango Active and Inactive Mines