2013-04-11_REVISION - C1996083 - Laserfiche WebLink

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STATE OF COLORADO DIVISION OF RECLAMATION, MINING AND SAFETY Department of Natural Resources 1313 Sherman St., Room 215 Denver, Colorado 80203 Phone: (303) 866 -3567 FAX: (303) 832 -8106 Memorandum April 11, 2013 To: Susan Burgmaier, DRMS From: Jared Ebert, DRMS i RE: Bowie No. 2 Mine; C- 1996 -083 Technical Revision No. 77 (TR77), Substitute Soil Analyses COLORADO D ] V I S I O N OF RECLAMATION MINING SAFETY John W. Hickenlooper Governor Mike King Executive Director Loretta Pineda Director As you have requested I have reviewed Technical Revision No.77 in regards to compliance to Rule 4.06.2(4) for the use of overburden material as a possible substitute to topsoil. Bowie Resources, LLC (BRL) is requesting to use excess coverfill material to replace and /or supplement the topsoil to be used to reclaim coal mine waste stockpiles at the site. Rule 4.06.2(4)(a) indicates selected overburden material may be substituted for, or used as a supplement to topsoil if the soil medium is equal to or more suitable for sustaining the vegetation than is the available topsoil, and the medium is the best available in the permit area to support revegetation. This rule continues to list the chemical and physical characteristics that must be analyzed to make this determination. The applicant indicates in the revision application that the original topsoil material found in the gob pile #2 area is comparable to the coverfill material proposed to be used as a replacement or a supplement to the salvaged topsoil. In 2003 soil chemical and physical analyses of the original topsoil material was conducted and incorporated into the approved permit in Exhibit 7 for the gob pile #2 and #4 area. The applicant took six samples of the coverfill material and conducted a laboratory tests on the samples. The results of the soil test for the coverfill material were submitted with TR77 to be included in Exhibit 7. The applicant offered a very limited analyses /comparison of the original topsoil material and the proposed substitute coverfill material. Using the lab data results from the 200' ) soil samples and the coverfill material samples, I created Table 1 included in Appendix A using Microsoft Excel® to compare the two soil materials. Appendix B includes charts created from the lab results data to aide in the comparison of the soil materials. Below is a discussion of each of the parameters the Division is required to analyze to determine if a soil medium can be used as a substitute or supplement to the available topsoil in accordance with Rule 4.06.2(4)(a)(i). Thickness of Horizons and Total Depth The original soil material in the gob pile #2/4 area was highly variable, the A horizon was very shallow (< Iinch). The A and B horizon were salvaged as one unit and were sampled and analyzed as one unit during the 2003 soil tests. The soil depth in this area was highly variable and ranged from 0 to 30 inches (Exhibit 7, Bowie No. 2 Mine PAP). The current approved reclamation plan calls for the replacement of .9 feet of topsoil material in this area and 3.1 feet of coverfill material (Volume IX, Bowies No. 2 Mine PAP). During TR76, the applicant requested a topsoil salvage variance in the gob pile #2 expansion area. The variance permits BRL to not salvage topsoil in areas that are too rocky, too steep or too thin to salvage in this area. BRL received approval for this variance and thus will likely not be able to replace the projected .9 feet of topsoil material in this area. Given this, there is a need for additional soil material to make up for the shortage. There is nothing to compare for this soil parameter, there is simply a deficiency of soil material and BRL would like to address this deficiency using the excess coverfill material at the site. Office of Office of Mined Land Reclamation Denver • Grand Junction • Durango Active and Inactive Mines