|
<br />In the response, the applicant did not provide the specific comparison of approved vs. existing as built
<br />typical cross-sections for CRDA-I and CRDA-2 as requested. Cross sections were provided only for
<br />CRDA-1(apparently existing cross sections), but no cross sections were provided for CRDA-2.
<br />Explanation will need to be provided. Unless adequate justification is provided, approved and as built
<br />cross sections will need to be submitted for the reclaimed benches of both CRDA-I and CRDA-2, if the
<br />operator chooses to pursue Phase I bond release request for CRDA-1 and CRDA-2 reclaimed benches.
<br />In addition, the Division requested the operator to document proper completion ofunderdrain installation,
<br />piezometric monitoring, construction and compaction compliance, stability, drainage/sediment control, and
<br />perimeter ditch and upland diversion construction and functioning. In response, the operator submitted the
<br />following information:
<br />• Excerpts from DMG inspection reports of June 29, 1994 and June 8, 1995 were submitted to
<br />document verification of adequate cover soil replacement.
<br />• Regarding underdrains, the operator submitted correspondence from 1983, and a Division
<br />inspection report from March, 1982, indicating that CRDA-I underdrains had been
<br />completed, and appeared to be functioning properly. Apparently, installation of the
<br />underdrain was completed in 1981, but the installation was not certified by aP.E., and an
<br />NOV was issued by DMG in 1993. Underdrains were not requved for CRDA-2.
<br />• Operator referenced quarterly piezometric data contained in annual hydrologic reports, to
<br />document compliance withpiezometric monitoring requirements. The monitoring data does
<br />document compliance with permit requirements.
<br />• Regarding compaction compliance, the operator's response referenced quarterly construction
<br />certifications and compaction reports, which are on file at the mine office and DMG offices.
<br />The certification reports document that construction was conducted in accordance with the
<br />approved design.
<br />• Regarding stability of the pile, the operator references stability analysis assumptions for both
<br />piles, and indicates that, based on the "as built final slopes" depicted on [he bond release map,
<br />the piles exceed the safety factor requrements of the permit and regulations.
<br />• Regarding the perimeter ditches at CRDA-I and CRDA-2, and the upland diversion ditch at
<br />CRDA-2, the operator states that the ditches have performed as designed and with very little
<br />maintenance.
<br />DMG and OSM conducted an intensive "special focus inspection" on August 5 through August 8, 1997 to
<br />evaluate compliance of refuse pile construction and reclamation with permit requirements. The lower
<br />benches of each CRDA pile for which Phase I bond release is now being requested, had been final graded,
<br />cover soiled and revegetated prior to that inspection (cover soiled and seeded in 1994). The DMG
<br />inspection report was issued on August 29, 1997, and afollow-up addendum with additional documentation
<br />of slope and terrace drain compliance evaluation, piezometric evaluation, and ditch design evaluation was
<br />completed on October 17, 1997. The August 29, 1997 report describes the inspection procedure as follows:
<br />The special focus inspection involved review of records associated with the refuse areas,
<br />including quarterly operator inspection reports/construction certifications, compaction
<br />reports, ptezometer monitoring records, stability analyses, and DMG refuse cover
<br />replacement documentation. Historical records were reviewed a[ the DMG mine offices,
<br />previous quarter records were reviewed at the PCC mine office.
<br />Field inspection included general assessment of active operations and reclaimed slopes
<br />at each refuse area, with respect to permit compliance, apparent stability, excessive
<br />erosion, vegetation establishment, and maintenance ofsurface wafer drainage controls.
<br />/n addition, field measurements using an abney level, 300 foot rape, and [ape measure
<br />>r~ere made 1o checkk apparen! compliance with permit specifications for final reclaim
<br />slope gradients; terrace drain spacing, slope and dimension; diverston/collec(ion ditch
<br />dimension, shape, and gradient; and culvert si=ing.
<br />
|