2003-07-11_REVISION - M1980244

• Permit No: M1980244
• IBM Index Class Name: Revision
• Doc Date: 7/11/2003
• Doc Name: Phase IV PSSA Area Cert Report
• From: DMG
• To: Cripple Creek & Victor Gold
• Type & Sequence: AM8
• Media Type: D
• Archive: No

June 24, 2003 -10- 003-2203.7
2.1.1 Remediation of Shafts, Stopes, and Shallow Surface Pits
The following is the general approach used to remediate isolated shafts and shallow surface pits:
For open workings where the depth to competent bedrock is less than 7 feet to
the final SLF subgrade surface, the excavations were backfilled with CSB to
approximately 10 feet below the finished surface grade. The surface of the CSB
was compacted using the shovel from a CAT 330b excavator. A 3-foot minimum
CP was cast into the shafr and allowed to cure for a minimum of 7 days. A
minimum ~-foot thick layer of CR 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 CR.
• For open workings where the depth to competent bedrock was greater than 7 feet
to the final SLF subgrade surface, the excavations were backfilled with CSB to
3 feet below the soil bedrock interface. The surface of the CSB was compacted
using the shovel from a CAT 330b excavator. A 3-foot minimum CP was cast
into the shaft and allowed to cure for a minimum of 7 days. A minimum 7-foot
thick layer of CR was then placed onto the CP. After the CR was allowed to
cure, SF was then placed to the final grade, as needed. Due to the depth of
weathered bedrock, working UG-494 was remediated using a 10-foot thick
concrete friction plug combined with the typical 3-foot CP plug and 7-foot thick
CR plug. In some cases, the excavation did not require placement of CSB prior
to placement of the CP and CR.
For collapsed workings extending deeper than 25 feet and where the depth to
competent bedrock was less than 7 feet to the final SLF subgrade surface, the
collapsed materials were excavated to a depth of 25 feet below finished grade.
The excavations were either backfilled with CSB to approximately 10 feet below
the finished grade or shaped for the CP at a workable depth below 10 feet. The
surface of the CSB or existing material was compacted using the shovel from a
CAT 330b excavator. A 3-foot minimum CP was cast into the shaft and allowed
to cure for a minimum of 7 days. A minimum 7-foot thick layer of CR was then
placed onto the CP. After the CR was allowed to cure, 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 CR.
For collapsed workings extending deeper than 25 feet and where the depth to
competent bedrock was greater than 7 feet to the final SLF subgrade surface, the
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 soiUbedrock interface or shaped for placement of the CP. The surface of the
CSB was compacted using the shovel from a CAT 330b excavator. A 3-foot
minimum CP was cast into the shaft and allowed to cure for a minimum of
7 days. A minimum 7-foot thick layer of CR was then placed onto the CP. After
the CR was allowed to cure, SF was then placed to the final grade, as needed.

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