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• • Revision q 1 - Psge 6 of 30 located along the west property line. The retention pond has been sized in accordance with the City of Grand Junction standards. Mining for the sand and gravel, and for a portion of the backfill operations, will requve dewatering. A pump will be used to dewater the excavation pit area and discharge into a new settlement pond constructed near the northwest corner of permit area. The settlement pond will allow the sediment to drop out of the water before it is discharged offsite into the Canning Factory Ditch. The side slopes for the pond shall be constructed at a 3H: I V, and all overburden removed for the pond construction shall be stockpiled around the pond perimeter. (d) The size ojareas to be worked at arty one time: Mining at the site will be progressive across the permit area, as discussed in part (a) above. The excavated pit area (backfill placement area, sand and gravel highwall, and overburden highwall) will be no more than three acres in size at any one time. The three-acre azea has been established to limit the amount of reclamation fill required to reclaim the site to approximately 130,000 to 150,000 cubic yards. (e) An approximate timetable to describe the mining operation. The timetable is jor the purposes of establishing relationship behveen mining and reclamation during the different phases ojthe mining operations. An Operator shall not be required to meet specific dates jor initiation, or completion of mining in a phase as may be identtfted in the timetable. This does not exemp! an operator from complying with the performance standards stared ojSectton 3. /. Such timetable shall include: • An estimate of the periods oJtime which will be required for the various stages ojthe operation: • A description ojthe size and location of each area to be worked during each phase: and • Outlining the sequence in x•hich each sage or phase of the operation wit! be carried out Mining for the sand and gravel will be progressive across the site, as discussed in part (a) above. As mining operations progress across the permit area, backfilling operations will be following behind the active sand and gravel highwall. The excavated pit area will be limited in size to no more than three acres in size at any one time. Once backfill has reached the site reclamation plan elevations, the area will be ready for preparing the area for seeding. To make the reclamation cost effective, the operator proposes to delay topsoiling, mulching, seeding and fertilizing until there is a maximum often acres to work, and the timing is such that planting can occur in the early spring or late summer months. The operator estimates it will requve around three years of mining operations before 10 acres will be ready for seeding. Also discussed above, the topsoil will be stripped Gom areas before surface disturbance activities occur. The maximum area for topsoil stripping shall 6e 10 acres. (~ Nature, depth, and thickness oflhe deposit [o be mined and the thickness and type of overburden !o be removed: and Nature of the stratum immediately beneath the material to be mined in sedimentary deposits. Overburden material within the project site is approximately 12 feet deep. According to the US Department of Agriculture, Department of Natural Resource Conservation Service (MRCS), the overburden soil consists of a silty clay loam that is not suited for cultivation due to high salinity levels. Vegetation on the project site consists of tamerisk, greasewood, and halogeton. These plants are listed on the State of Colorado's noxious weed list. The top two to six inches of existing topsoil material will be stockpiled and reused for site reclamation work. A 10-ft to 20-ft lens of sand ,gravel and cobble material is located under the overburden material described above. This material will be extracted and processed. In general, the upper portion of