2013-06-18_REPORT - C1996083 - Laserfiche WebLink

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Bowie No. 2 notes for site visit June 13, 2013: Bench #2 of Gob Pile #2 has been brought up in grade to where it now nearly ties into Gob Pile #4 (Where Ditch D17 will drain into D14). Compaction testing was scheduled for the Bench #2 area on Friday, June 14. Old Ditch F20 and F11 are still in place. During the site visit we discussed plans for placement of coverfill on gob pile #4. In the near future, a road will be built from the cut slope associated with TR -76 to gob pile #4 in order to start hauling coverfill material for placement on the West half of gob pile #4. A ditch will be cut on the inside of the new haul road and drainage will be directed to the existing haul road and will ultimately end up in Pond F. Once the haul road between piles is built, part of old Ditch F20 will be covered up. Drainage will be continually changing as it is brought up to grade. The equipment operators are diligently working toward creating and maintaining positive drainage. Bill Bear and I walked the new section of West Diversion Ditch #1. The ditch was constructed as designed, but it was cut through a thicker than anticipated section of the coal fines of the old King Mine, so there are near vertical sections remaining on the upslope side of the ditch. I spoke with the contractor who constructed the ditch and he deliberately pulled material from the upslope and cast it over the edge to try and reduce the steep slope, but was never able to catch grade and force slope equilibrium, so in a few locations there are near vertical sections 3 -4' high. We are meeting Dan Quigley with Buckhorn Geotech on -site on Wednesday to evaluate options for maintenance going forward. Global failure of the slope is not a concern, but there will be some surficial slumping until the slope reaches equilibrium. Where the ditch ties into the existing ephemeral drainage there will be rock placed in order to dissipate energy and protect the natural channel from erosion. During construction of the new ditch, a stacked wall, potentially a cultural resource, was uncovered almost directly below the King Mine. The wall is located on private surface owned by Bowie. The wall was not damaged. DRMS has been directed by SHPO to have a cultural resources consultant survey the area and provide documentation of the find. At this time, it is unknown when the area will be surveyed. Pond F has been dewatered and sediment removal has begun. A significant amount of sediment accumulated in the Pond over the winter. I am working on a drainage revision to address the required and available sediment storage for the Pond F design. Bill, Dewey and Jim met with CDPHE to discuss the air permit for gob pile #3 on Tuesday June 11. Overall, the outcome was positive. Once the current model is revised, re- submitted to and accepted by CDPHE, they will grant enforcement discretion and allow Bowie to start using the pile while the permit is finalized. It is anticipated enforcement discretion, and use of gob pile #3 will occur before the winter, possibly as soon as September. While re- grading DF17 as part of the NOV- 2013 -004 abatement, water was discovered exiting gob pile #4. A French drain was installed and the flow will outlet approximately into F9. In reviewing old photos of gob pile #4, it is evident dewatering of Gob Pile #4 has been occurring in that location for at least two years. The piezometers installed on gob pile #2 have indicated that overtime coal waste dewaters and eventually will have no phreatic surface (from BGI report dated 11 -20- 2012). I also communicated the water /french drain installation to Dan Quigley and we will look at the location on Wednesday, but he did not express concern about the piles dewatering and said that is how they are supposed to function. We will continue to monitor the french drain area. To comply with DRMS conditions of approval for planting the test site on gob pile #2, 5 holes were augered in the area to be used as a test section for TR -77. The approximate locations are shown on page 3. All five holes had four feet of coverfill.