Laserfiche WebLink
111 <br /> M-2001-001 Line Camp Pit Amendment#2 (Expansion) <br /> a. Task: Prevent potential damage from mining in the existing pit and expansion area. <br /> (Zone I and the south portion of Zone II are existing: rest of Zone II and Zone 3 are the <br /> expansion area.) <br /> b. Conditions: The existing and proposed pit (measured from the head of the working face, <br /> with a slope not greater than 2H:1V, ranges from 100 to 500+ feet from the near edge of <br /> the riverbed (the OHWM). Zone I as mined prior to 2024 is only 100 feet from the <br /> OHWM, as approved in the original and AM-01 applications. Zone II is adjacent to an <br /> ephemeral and mostly silted in side channel, and is 200 to 500 feet from the OHWM. <br /> 1. The northern half of Zone I has existed since approximately 2009; the southern half <br /> of Zone I has existed since approximately 2013. Both have been stable 10+ years. <br /> 2. There have been multiple high-water events and no significant erosion on either <br /> riverbank or pitside bank since the initial excavation of the adjacent pit areas. <br /> 3. The riverbed of the Dolores River at this point consists of cobbles and boulders, with <br /> little or no silt or sand (fines) in and below the river bottom. <br /> 4. A pipe and outfall for which design and approval was granted by DRMS in 2002 <br /> drains the ponds when the water surface of the pond is above the OHWM, and is <br /> also used for pumped dewatering discharges. This outfall is in the riverbed and <br /> permitted by CDPHE-WQCD. It is inspected annually. <br /> 5. The natural, in-place alluvium on both banks and the top of the area is essentially a <br /> compacted soil riprap which meets the guidance of Chapter 8 of the USDCM. It has <br /> established vegetation including willows, reeds, and cottonwood trees. <br /> 6. Disturbance of this would actually reduce the protection offered by the existing <br /> conditions until vegetation could be reestablished. <br /> 7. Although this situation does not meet the 2024 guidelines, it is the professional <br /> opinion of the preparer that any changes are likely to increase potential for pit <br /> capture and other problems. <br /> c. Standards: as per 15 February 2024 DRMS Floodplain Protection guidance and USDCM <br /> (See also Exhibit E Item 7) <br /> d. Tasks (as part of mining and reclamation) to be done by operator/personnel: <br /> 1. Inspect and document both (with photographs and measurements) pitside and <br /> riverbank conditions on a frequent schedule, including: <br /> a. Annually before beginning of snowmelt upriver. <br /> b. Annually before seasonal operations begin. <br /> c. Within 24 hours of any precipitation greater than 0.1 inches on site or when <br /> river levels rise more than 2 feet above OHWM. <br /> d. Annually at end of seasonal operations. <br /> e. Annually before significant snow accumulations. <br /> 2. Maintain and repair pitside banks and river banks above OHWM: <br /> a. Immediately following any observation of rills, erosion, slippage, and destruction <br /> of vegetation, both on permit and off-permit with landowner approval. <br /> b. Fill and compact voids in natural soil riprap as they are identified, as per USDCM <br /> Figure 8-35. <br /> c. Document (with photographs) all work. <br /> d. Inspect all work not later than 7 days and 14 days after work is done. <br /> 3. Observe and remove/relocate snags in the riverbed which might cause changes in <br /> river flow which could increase erosion of the riverbank. <br /> a. Note this has been done regularly in the past by operators. <br /> b. Coordinate with landowner before and after doing work. <br /> 4. Exercise care in beginning excavation on the pit edge near the riverbank. <br /> a. Inspect ground stability before and after stripping soil. <br /> 5182-22-001 WASTELINE, INC. Page 40 of 65 <br />