GENERAL47948

• Permit No: C1981013
• IBM Index Class Name: General Documents
• Doc Date: 12/15/1982
• Doc Name: Proposed Decision and Findings of Compliance
• Permit Index Doc Type: Findings
• Media Type: D
• Archive: No

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In addition, the Division is unable to consider approval of the depression on
the basis that it meets the approximate general nature of the preinining
topography or the proposed post-mining topography, as CF&I contends. The
applicant has not submitted a contour map and cross-sections that depict the
pre-mining topography. Therefore, the following stipulation is necessary.
Stipulation No. 22
WITHIN 120 DAYS OF PERMIT ISSUANCE, THE PERMITTEE SHALL SUBMIT A REVISED
BACKFILLING AND GRADING PLAN, INCLUDING A REVISED CONTOUR MAP AND
CROSS-SECTIONS OF THE POST-MINING TOPOGRAPHY. THE PROPOSED POST-MINING
TOPOGRAPHY SHALL COMPLY WITH THE REQUIREMENTS OF APPROXIMATE ORIGINAL
CONTOUR AND SHALL ELIMINATE ALL DEPRESSIONS. IN ADDITION, THE REVISED
CROSS-SECTIONS SHALL SHOW THE PRE-MINING TOPOGRAPHY. THIS PLAN WILL 8E
SUBMITTED AS A REVISION TO THE PERMIT.
XVIII. Coal Processing Waste and Non-Coal Processing Waste -
Information on refuse disposal can be found on pages 2.05-22 through 2.05-26
of Volume I, Exhibit 15 of Volume II, Map 14 within Volume IV and in the
applicant's response of December 20, 1982 response to the Draft Findings. The
information has been reviewed by the Division for compliance with the
requirements of the above regulations.
The waste material sample analysis and mathematical slope stability analysis
provided within the application demonstrates that the proposed coal processing
waste pile will achieve a static slope safety factor that exceeds the
requirements of Rule 4.10.4(2). The proposed construction specifications for
placement and compaction of materials at the coal processing waste pile are in
compliance with the requirements of Rule 4.10.4.
Test pits excavated at the .site of the coal processing waste pile have
determined that the foundational area is underlain with between 2 and 4 feet
of granular material. The applicant believes that these materials will
function as an appropriate natural subdrain. Based on evidence gathered by
the Division's staff on July 27, 1983, it was determined that a minor amount
of ground water (approximately 2 gallons per minute) occurs in the surficial
deposits beneath the proposed processing waste pile at the Maxwell Mine. The
surficial deposits thicken from several feet at the southern extremity of the
proposed pile to several tens of feet near the northern extremity of the
pile. The applicant contends that these naturally occurring surficial
materials will act as a subdrain, preventing the pile from contacting ground
waters. This will probably be the case for the northern portions of the
pile. However, ground water may contact waste material within the southern
portions of the pile's foundational area. The several feet of apparent
separation is inadequate to assure prevention of potential capillary rise of
ground water into the waste material.
The stability analyses performed by the applicant have demonstrated, in
accordance with Rule 4.10.3(5), that the pile will remain structurally stable
even if saturation occurs. However, the applicant has not demonstrated that
the proposed design will protect ground water quality.