2008-09-29_PERMIT FILE - C1981019A ‎(10)‎

• Permit No: C1981019A
• IBM Index Class Name: Permit File
• Doc Date: 9/29/2008
• Section_Exhibit Name: 4.09 Disposal of Excess Spill and Underground Development Fill Waste
• Media Type: D
• Archive: Yes

RULE 4 PERFORMANCE STANDARDS
4.09 Disposal of Excess Spill and Underground Development Fill Waste
Colowyo originally constructed the excess spoil fill known as Streeter Fill in accordance with Section
2.06.2, Experimental Practices Mining. The details of this alternative spoil disposal practices are set forth
in Section 2.06.2.
On March 3, 1986 Colowyo submitted a request to the Division for a Technical Revision to change the
status of the Streeter Fill Experimental Practice. The request was to change the Streeter Fill to an excess
spoil fill designed and constructed under the alternative design standards set forth in Rule 4.09. (3). All
the monitoring requirements of the fill will remain as originally approved to insure the stability
requirements of Rule 4.09 are met.
The Division approved the revision on August 18, 1986.
For further details regarding this Technical Revision and the history of Streeter Fill, refer to Section 2.06,
Special Categories.
In December, 1993, Colowyo proposed a Technical Revision to the Division to reduce the monitoring
requirements for Streeter Fill. During the 1993 - 2006 period, the following monitoring plan was
implemented:
Streeter Fill Monitoring and Inspection Plan for Streeter Fill (1993-2006)
1) Colowyo conducted monitoring of the 12 Streeter Fill survey monuments once a year, during
the second calendar quarter of each year. For a location of the twelve survey monuments
(6700 N and S through 7200 N and S) and the baseline reference monuments (AH-21, RP-2
and SRP-3) refer to Drawing 30A - Revised Streeter Fill As-built. The revised Drawing 30A
is intended to update the Permit only with respect to 1) the Streeter fill survey monuments, 2)
baseline reference monuments and 3) the wells (W6900N, W6900S and W6700). The
original Drawing 30 - Streeter Fill Design and As Built will remain in the Permit and serve to
represent all other aspects of Streeter Fill.
2) Colowyo monitored water level in the Streeter Fill piezometer well (W6700) and conduct a
spring and seep survey quarterly.
3) In the event that the water table in the piezometer well rises to a level greater than 10 feet
above bedrock, Colowyo agreed to notify the Division within 2 working days and to complete
a survey of the twelve subsidence monuments and report the results to the Division within
one month.
4) Colowyo completed an annual inspection of the Streeter Fill each year of this time period
during the second calendar quarter by a registered engineer. This inspection included a
specific examination of items 1 and 2 above and included a discussion of the facial conditions
of the fill in order to determine whether the development of perched water tables within the
fill was affecting its surficial slope stability.
5) The monitoring reports and certified inspection reports are available during inspections by the
Division but were only submitted to the Division in the Annual Reclamation Reports.
On 9/9/97 monitoring of the 6900 well indicated that the steel casing had failed at the 114.3' level
allowing water from a pre-existing perched water zone to enter the well at that level. Subsequent
Rule 4 Performance Standards 4.09-1 Revision Date: 6/23/08
Revision No.: MR-91