PERMFILE118835

• Permit No: M2006039
• IBM Index Class Name: Permit File
• Doc Date: 9/25/2006
• Doc Name: Prelminary Adequacy Review Response
• From: Cordilleran
• To: DRMS
• Media Type: D
• Archive: No

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CORDILLERAN
Exhibit D -Reclamation Plan
826 21 '/ Road
Grand Junction, CO 81505
T: 970.263.7800
F: 970.263.7456
10. Per Rule 6.3.4(1)(a), please provide timing specifics for when reclamation begins. Include details
if reclamation is to be contemporaneous with excavation such as a phased plan.
Reclamation will begin upon the completion of all mining activity on the site. No phasing or
contemporaneous reclamation will take place due to the limited amount of space on the site.
11. Per Rule 6.3.4(1)(b), please provide an engineer's demonstration that the proposed final slopes
are stable to a safety factor of 2 or reduce the final slope configuration accordingly. This
demonstration must include demonstration of stability for the slopes above the excavation, as
they would be affected by the removal of the toe of the slope without buttressing or other means
of stabilization proposed.
A Slope Stability Analysis was done for this site to "assess slope stability of the existing, active pit and
reclaimed pit slope configurations on both a global and local scale." The analysis of global stability
indicated "a minor reduction in calculated, minimum factor of safety for the existing slope (1.38) to the
predicted, reclaimed pit configuration (1.29 to 1.35)."Analysis of local stability focused on the lower slope
portion of the proposed materials mine. This analysis yielded a similar reduction in the calculated
minimum factor of safety due to development of the mine. Analysis of the existing slope configuration
indicated a minimum safety factor of 1.5. Analysis of the active and reclaimed pit slope configurations
indicated minimum factors of safety of about 1.3.
It is understood that the DMRS has recommended a final slope configuration of 2: 1. However, the Slope
Stability Analysis has demonstrated a suitable safety factor fora 1:1 slope with a maximum height of
about 150 feet. Chevron hopes that the DMRS will find this acceptable and amend their recommendation
to allow a final slope configuration of 1: 1. If the DMRS does not agree with the suitability of a 1:1 slope,
Chevron will, of course, follow the DMRS recommendation.
The complete Slope Stability Analysis is located in Attachment 11.
12. Per Rule 6.3.4(1)(c)(i), please specify how and to what depth growth medium will be replaced to
best improve the chances of successful vegetation.
Reclamation will begin by bringing the slope to 1 h to 1 v. The most reasonable way to attempt to reclaim
the site will be to use a track hoe to push down material from the top terrace down the face of the slope to
create a more favorable angle of repose. While the track hoe works back from the terraces it will create
pockets with its bucket to dissipate scouring from water erosion. These pockets will provide a collection
point for fine materials that will produce a more favorable seed bed. Pockets also increase the retention of
water on the slopes. Landscape materials salvaged during initial excavation of the site will be
mechanically and/or hand-placed to reinforce these pockets. Stockpiled salvaged topsoil will be
distributed across the pockets at a depth of approximately 2 to 6 inches. The size and frequency of the
pockets will be dependent upon the size and type of equipment used to create them.
13. Per Rule 6.3.4(1)(c)(ii), please specify at what point in the mining/reclamation process
revegetation will begin.
The pocketed slopes will be revegetated in the fall immediately following the commencement of all mining
activities.
14. Given the limited amount of growth medium apparently available for reclamation and the dry,
rocky nature of the proposed fill slopes, DRMS recommends that the seed mix be revised to
include several dryland shrub species such as Wyoming big sagebrush, antelope bitterbrush,
mountain mahogany, Stansbury cliffrose, and rubber rabbitbrush. The seed mix species
percentages should be revised accordingly, depending on the number of shrub species and
Cordilleran Compliance Services, Inc.
Grand Junction, CO • Denver, CO • Casper, WY • Laramie, WY • Lander, WY
Environmental Consulting Engineers and Scientists