Laserfiche WebLink
III. COMMENTS -COMPLIANCE <br />Below are comments on the inspection. The comments include discussion of observations made <br />during the inspection. Comments also describe any enforcement actions taken during the inspection <br />and the facts or evidence supporting the enforcement action. <br />This was a partial inspection of the New Horizon Mine, conducted by Dan Mathews of the DMG Grand Junction <br />Field Office, 101 South 3`d, Suite 301, Grand Junction, CO 81501. Weather was clear to partly cloudy and <br />warm. <br />The inspection was made in response to a phone call that Ross Gubka of Western Fuels-Colorado had made to <br />Mike Boulay in the DMG Denver office to report the results of a high intensity rainfall event that had occurred at <br />the minesite on the afternoon of Monday, July 10. Mike Boulay relayed the gist of his phone conversation with <br />Mr. Gubka to me later the morning of July 11, and requested that I conduct a site inspection to observe and <br />document the effects of the storm event. Mike indicated that his understanding was that the storm event had <br />resulted in several breaches of sediment pond collection ditches, which may have resulted in erosion and/or <br />sediment deposition in areas outside the sediment containment system and possibly off the permit area. Shortly <br />after my phone discussion with Mike Boulay, I left the office and drove to the New Horizon mine site, where I met <br />Ross Gubka at the mine office at approximately 2:00 pm. We proceeded from the mine office in Mr. Gubka's <br />vehicle, to observe various locations that had been impacted by the storm event. <br />General Overview <br />Ross Gubka explained that a very localized storm cell had moved across the mine area from the west late the <br />previous afternoon (July 10). At the Pond 7 rain gage, total precipitation of 1.1"was recorded, somewhat less at <br />other rain gage locations on the permit area. The storm event was brief and intense, lasting approximately 1 <br />hour. The 1.1" rainfall is substantially less than the 2.0" rainfall associated with the 10-year, 24-hour storm <br />("design event"). I do not know how the peak runoff produced by the high intensity one hour event would <br />compare to the peak flow produced by the design storm event. <br />The primary concern of Mr. Gubka and the Division was that the high runoff caused by the storm event had <br />breached several disturbed area collection ditches. We observed 4 general locations where breaches occurred, <br />which I refer to below in this report as Breach #1, Breach #2a and 2b (lwo closely spaced breaches along the <br />same ditch segment), Breach #3, and Breach #4. In general, results of the breaches appeared to be limited to <br />minor erosion and sediment deposition outside the sediment collection system but inside the permit area, and <br />minor sediment deposition outside the permit area. Sediment deposition filled in several short segments of <br />county road ditches and possibly blocked one or more county road culverts immediately adjacent to the permit <br />boundary. Sediment deposition on private properties adjacent to the permit area was very limited and impact <br />appeared to be insignificant. <br />By the time of the inspection, the operator already had atrack-hoe on site and had initiated ditch and culvert <br />repairs. We discussed further work that was planned and I indicated that the operator would need to promptly <br />restore the county road ditches impacted by mine area runoff/sedimentation to design condition. Clean-out <br />repair of any county road culverts impacted by mine runoff/sedimentation will also be required. <br />Finally, I indicated to Mr. Gubka that issuance of an enforcement action was likely, but that the determination <br />would be made by Mike Boulay and Sandy Brown in the Denver office, based on review of my report and a <br />report that he had been requested to submit to DMG Denver. <br />Breach #1 <br />Location is along lower end of the disturbed area collection ditch that reports to Sediment Pond 7 from the west, <br />along the south side of the permit area. Approximately 100 yards to the west of Pond 7, the ditch had been filled <br />in to allow farm equipment access to the reclaimed pasture areas. A culvert had been installed to pass ditch <br />flow under the field access crossing at some point in the past; a 14" black plastic culvert had been used. A 6" <br />black PVC pipe that conveys pit water to Pond 7 was also routed through the culvert. This culvert had clogged <br />as a result of the storm event, and the ditch breached at the culvert inlet location. Subsequent to the storm <br />event and prior to my inspection, the ditch in vicinity of the culvert had been excavatedlenlarged, and a new 18" <br />CMP culvert had been installed at the crossing. Ditch excavation with the track-hoe was in progress up-gradient <br />(west of) the culvert at the time of inspection. Photo #2589 is view of the culvert location from the east looking <br />