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.~ _ III IIIIIIIIIIIIIIII 14 May 1986 Colorado Mined Land Reclamation Division Attention: Mr. Randy Price 6 J.A.Pendleton 423 Centennial Building 1313 Sherman Street Denver, Colorado 80203 Gentlemen, ~_. ..~.- MAY 1 ~ 1986 • ,~ As you are aware, there has been some reactivation of the surfi- cial landslides and debris chute within the permit boundaries of the Bear No 3 Mine. This occurred on April 3 ~ 4 The mine lost a few days production because the slide flowed over our ventila- tion fan and blocked the access road to the portals. Immediate remedial actions taken included the following measures: 1. Removal of the workforce from the area 2. Consultation with Rocky Mountain Geotechnical, Inc. 3. Notification of Agencies 4. Monitored activity until movement stopped 5. Removed the damaged fan and cleared the access road 6. Installed old mine cars filled with colluvium around the fanhouse to stiffen resistance and form a protective pressure arch within the slide. 7. Installed a new fan 8. Continued monitoring by daily visual inspection A copy of our geotechnical consultant's inspection report was delivered to you on your visit to the mine May 7, 1986. We feel the mechanisms which caused reactivation of the slides on our property, as well as numerous slides throughout the north fork valley were as follows: 1. Preexisting slides on relatively steep slopes. 2. A generally wet weather cycle over the past 3 or 4 years. 3. Warm mild weather in January & February removed the frost line from the ground. This allowed springs rains and runoff to penetrate more deeply into the old slides than usual. 4. The additional moisture weakens the cohesive strength of the soils and we see shallow slides and slumps. For the short term: The movement has stabilized, but we are con- tinuing to monitor it. Rocky Mountain Geotechnical Inc. is analyzing the area and working on design of remedial measures to minimize exposure to our workforce and facilities. The water draining from the slide and debris chute is being channeled into flexible pipe and diversion ditches into the sediment pond.