2008-06-04_PERMIT FILE - M2008022

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RECEOVED DATE: TO: FROM RE: June 4, 2008 Russ Means .? K t Pickford? JUN 16 2008 Division of Reclamation, Mining and Safety ae Hydrology Review of 4B Lar dl& Livestock, LLC, Breeze Basin Sand & Gravel Pit, File M-2008-022, Application for a I I2c Permit and comments received from The Deep Cut Irrigation Ditch, Inc. The Division has reviewed the hydrologic content of 4B Land & Livestock, LLC, Breeze Basin Sand & Gravel Pit, File M-2008-022 Application for a 112c Permit and comments received by the Division from The Deep Cut Irrigation Ditch, Inc, and submits the following comments. The Division believes that the irrigation ditch company's concern related to groundwater being drawn into the ponds during seasons when the groundwater becomes part of the river and irrigation channel, as is described in its letter, are unfounded. The water level in the ponds will naturally be a reflection of the groundwater levels in the area, at any given time. The ponds will not pull water from the surrounding area resulting in a higher level in the ponds than in the adjacent groundwater. The Division agrees with concerns voiced by the irrigation ditch company regarding the stockpiling of topsoil, in that these stockpiles may be located within the flood plain of the Yampa River. Therefore, the Applicant should indicate how erosion and loss from these stockpiles will be addressed. Also related to the location of the Yampa River flood plain, there is some concern that the river could become rerouted through the ponds, in that they are located about 100 feet from the river. Presumably the Division's staff engineer will address this concern in his comments related to the site, as well as concerns related to stability Two concerns not identified in the Irrigations Ditch's letter, that should be addressed by the Division relate to dewatering of the pits. The mine plan indicates that the pits will be dewatered one at a time during the mining process. The Applicant should identify the expected cone of depression, including the depth and the radius, related to this dewatering activity. Potential impacts to sub irrigated vegetation, including cottonwood trees, if present, should be addressed by the Applicant, if this vegetation is to be protected. If impacts are expected, the Applicant should indicate measures that will be taken to avoid or minimize these impacts, to include establishing the seasonal groundwater level within and around the permit area; monitoring of the groundwater level and vegetation in the area; mitigation measures that will be implemented if groundwater is impacted by the dewatering activities; and a trigger point that will signal when mitigation measures must be implemented.