2015-09-04_PERMIT FILE - M2015017

• Permit No: M2015017
• IBM Index Class Name: PERMIT FILE
• Doc Date: 9/4/2015
• Doc Name: Adequacy Review No. 2
• From: DRMS
• To: Greg Lewicki and Assoc
• Email Name: MAC
• Media Type: D
• Archive: No

Sullivan Pit Engineering Review Memo
Page 2 of 2
September 3, 2015
The Factor of Safety calculation provided by the Applicant is not sufficient to elevate the
slope stability for the proposed operation. Please perform stability analysis models on the
critical slope configurations during the mining and reclamation of the proposed operation.
2. The required stability analysis models must include surcharge loads from structures, roads
(State Highway 9), topsoil stockpiles and any other appropriate loads.
3. The Applicant states during placement of the backfill material, the Operator will compact
(the backfill) using standard earthmoving techniques. Please describe the earthmoving
techniques to be used during the placement and compaction of the backfill material.
4. The Applicant states all material over %" in size will remain in the pit and will be mixed with
overburden in the backfill. Please describe how the Applicant will mix and test the over %"
material and overburden to achieve a consistent composition for the backfill material.
5. The final reclamation slope for the pre -law highwall in the sluice area in inaccurately
depicted as a 3H:1V slope on Exhibit C-2 — Mine Plan map in cross-section D -D'. Please
update Exhibit C-2 to depict the proposed 2.2:1V reclamation slope.
6. Please update the list of structure in Exhibit S to include the minimum distance between the
structures to the excavation limit boundary. Please update the Exhibit C-2 — Mine Plan map
to indicate the offset distances.
7. The Applicant did not provide a typical soil profile description or illustration. Please provide
a typical soil profile for the stability analyses models.
8. Please provide geotechnical borehole data, if available, for the site for Division review.
9. Please provide soil property lab data, if available, for the site for Division review.
10. Please provide the Division with the slope stability monitoring plan to be used during mining
and reclamation activities at the site.
The Division will verify the Applicant's stability analysis models using Clover Technology's
Galena v6.1 slope stability software following the Applicant's response to this letter.
If you have any questions, please contact me at [phone] Ext. -8124.
Cc: Wally Erickson; Division of Reclamation, Mining & Safety