Laserfiche WebLink
Minine Methods <br />Groundwater is not expected to be encountered during mining and the deposit will be dry mined. <br />Mining will proceed by first stripping and stockpiling topsoils and overburden. This includes the <br />upper 0 to 6 inches of topsoil and 0 to 6 feet of overburden. All topsoil shall be stockpiled for <br />use in final pit reclamation. The exposed gravel will then be removed in lifts and transported to <br />the processing facility. Since the material is unconsolidated deposits, no blasting is required. <br />The Lone Tree Creek drainage does not have an associated regulatory floodplain within the <br />proposed permit area. Because of the incised nature of the creek, wetland communities appear to <br />be restricted to the channel and immediately adjacent areas, with a very steep and rapid transition <br />to uplands. Mining will, therefore, occur adjacent to the creek drainage. A variable excavation <br />buffer will leave enough elevation and distance to not disturb the creek channel and associated <br />wetlands and minimize flooding of the pit floor during periods when the creek flows. <br />Unlike most rivers and streams along the Front Range of Colorado, very little or no alluvial sand <br />and gravel deposits are associated with the Lone Tree Creek channel. However, in some areas, <br />the terrace deposits occur right up to the high and steep embankment of the incised creek <br />channel. In these upland areas, aggregate will be excavated from the embankment, lowering the <br />adjacent land surface to match the depth of the pit floor without disturbing the creek channel (see <br />Exhibit C -5, Pre- Mining/Mining Plan Map). <br />Earth Moving <br />Areas to be mined are prepared by removal of topsoil and overburden. Each preparation area <br />may be as much as 100 feet wide. Usually, only enough area is stripped and prepared to provide <br />the estimated needs for the next 10 to 14 months of mining. Where it is found, surface topsoil <br />material will be stripped separate from the underlying, deeper subsoil or overburden material. <br />This topsoil layer contains most of the soils organic matter and will be stockpiled separately for <br />use in reclamation. Once the surface layer has been removed, the rest of the overburden will be <br />stripped and stockpiled separate from the surface layer. <br />The active mining face will extend no more than 1,000 feet in length. During mining and prior <br />to reclamation, the mine walls will be a nearly vertical to %ZH:1 V slope (see Exhibit C -5, Pre - <br />Mining/Mining Plan Map). Mining will progress down to the depth of quality aggregate material <br />or 5 to 25 feet below the surface. As the mining face progresses, pit sidewalls will behind the <br />mining activities will reclaimed. So reclamation activities do not interfere with mining <br />operations, pit sidewalls may extend 500 feet behind the active mining face without being <br />reclaimed. The aggregate material will be recovered using equipment typical for sand and gravel <br />mining operations. Earth moving equipment may include, but are not limited to dozers, loaders, <br />scrapers, and excavators. The aggregate material from the pit will be temporarily stockpiled <br />within the pit or transported directly to the processing facility. During mining and reclamation <br />activities, watering trucks for dust control will be used as needed. <br />Setbacks from the mine pit top of slope to the proposed permit boundary or man -made structures <br />not owned by the applicant shall be 50 feet or greater. To mitigate stability risks adjacent to <br />man -made structures not owned by the applicant, the mine pit top of slope setback shall be <br />Connell Carr Pit <br />DRMLIS 112 Permit application adequacy Review Response <br />