2015-12-03_REPORT - M1980244

• Permit No: M1980244
• IBM Index Class Name: Report
• Doc Date: 12/3/2015
• Doc Name: Final Report, QA Monitoring & Test Results
• From: Cripple Creek & Victor Gold Mining Company
• To: DRMS
• Email Name: TC1
• Media Type: D
• Archive: No

Al.
Cripple Creek&Victor Gold Mining Company
Squaw Gulch VLF Phase 1 (9,450 foot to 9.550 foot bench) amec
Final Report Addendum foster
Quality Assurance Monitoring&Test Results wheeler
December 1. 2015
2.1.1 Remediation of Shafts, Stopes, and Shallow Surface Pits
The following is a general approach used to remediate isolated shafts and shallow
surface pits (refer to figure UG1 in Appendix M.1 of the report for visual representation
of the descriptions below):
Open Workings:
For open workings, the excavations were backfilled with CSB to approximately 10 feet
below the finished surface grade. The surface of the CSB was compacted using the
bucket from a Caterpillar excavator. A minimum 3-foot-thick CP was cast into the shaft
and allowed to cure for a minimum of 7 days. A minimum 7-foot-thick layer of CRF was
then placed onto the CP. SF was then placed to the final grade as needed. In some
cases, the excavation did not require placement of CSB prior to placement of the CP
and CRF.
Collapsed Workings
For collapsed workings, collapsed materials were excavated to a depth of 25 feet below
finished grade. The excavations were either backfilled with CSB to approximately 3 feet
below the soil/bedrock interface or shaped for placement of a CP. The surface of the
CSB was compacted using the bucket from a Caterpillar excavator. A minimum 3-foot-
thick CP was cast into the shaft and allowed to cure for 7 days. A minimum 7-foot-thick
layer of CRF was then placed over the CP. After the CRF was allowed to cure, SF was
then placed to the final grade as needed.
Shallow Surface Pits
Shallow surface pits that were less than 25 feet below the final SLF grade were
excavated to bedrock or pit termination. The pits were then backfilled with compacted
SSF and SF to the bottom of the SLF layer. In some cases, shallow surface pits were
completely removed during slope re-contouring and required no further remediation.
2.1.2 Remediation of Lateral/I ncli nes/Ad its
A number of laterals and adits were identified within the Phase 1 VLF footprint. Per the
remediation recommendations, historic underground workings were identified within 50
feet of the existing grade elevation and remediated. Workings that were 50 feet or more
below the final grade were not remediated.
Remediation for laterals and adits consisted of drilling nominal 3-inch-diameter blast
holes into the crown pillar (the rock between the ground surface and the roof of the
working) using a pneumatic hammer track drill rig. The blast holes were loaded and the
crown pillars blasted into the void. For some of the shallower workings, the blasted
material was excavated and replaced with compacted fill. For deeper blasted laterals
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