2016-09-12_REVISION - C1982056 - Laserfiche WebLink

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Tuent-vmHe Coal. ULC fit# Peabetq 24515 RCR 27 Oak Creek. CO 80467 Twentymile Coal, LLC 970.870_3800 August 30, 2016 RECD UM Mr. Jared Ebert, Environmental Protection Specialist SEP h '' x u Division of Reclamation, Mining and Safety DIVISION CF RECLAJ,IATICN 1313 Sherman St., Room 215 MINING kND SAFE TY Denver, CO 80203 (303)866-3567 Z 8120 RE: Twentymile Coal, LLC — Foidel Creek Mine (Permit No. C-82-056) Technical Revision TR16-85, Hydrologic Monitoring Reductions Mr. Ebert, Twentymile Coal, LLC (TC) is requesting approval from the Colorado Division of Reclamation, Mining, and Safety (CDRMS) for a Technical Revision to our existing Permit to reduce or eliminate specific hydrologic monitoring requirements for the Foidel Creek Mine. TC requests approval to deactivate three alluvial groundwater monitoring wells (AVF-14, AVF-15, and JONES) along with two associated stream monitoring sites (SW -14 and SW -15). The AVF-4 and AVF-15 wells were originally installed for subsidence assessment during mining of the Wadge Seam in Twentymile Park beginning in 2002. It is our understanding that the Jones well was historically monitored to assess potential mine discharge impacts to the Jone's potable water well. In 2007, Mr. Jones constructed a weather/rodent cover and sealed off the well, restricting access for taking water -level measurements, but still allowing water quality samples to be collected. In the fall of 2008, TC provided the Jones family with underground water storage tanks, a new plumbing system, and imported water, so that they could discontinue use of the well. At that time, the old plumbing system to the Jones well was decommissioned, eliminating alluvial water sampling access. The subject monitoring sites are no longer necessary or relevant to the current mining activities and associated impacts. TC plans to deactivate the monitoring sites listed above, and eliminate the associated monitoring requirements. In addition, TC is also requesting approval to modify the stream monitoring schedule during the months of March, August, and September. Due to winter conditions that hinder accurate stream monitoring during the month of March, TC is proposing to modify the monitoring schedule to start during the month of April, when winter conditions typically begin to ease. TC is also proposing to reduce stream monitoring under Schedule B during the months of August and September consistent with the current monitoring schedule for the earlier months of the years, where monitoring is only required for each site once per month instead of the current weekly schedule for the month of August and first two weeks in September. This will result in a reduction in the number of monitoring events from twelve down to seven. Details concerning this reduction may be found in Exhibit 14 of the enclosed permit document. Attached are the required application form, public notice, insertion instructions, and the revised/updated materials. Enclosed are three copies of our application for a technical revision to the Foidel Creek Mine Permit (Permit No. C-82-056).