2010-05-25_REVISION - C1981008 (8)

Home Browse Search

disturbance area), soil mapping units. These units (98D and 98E) occupy about 52 percent of the proposed 1999 disturbance area. Soil units 98A and 98E were determined to be "prime farmland soils" by the NRCS in January, 2008. Soil handling from February 2008 onward has been modified to account for this change in designation. A letter from the NRCS dated August 4th of 2009 has defined the distinction between prime farmlands and prime farmland soils. This letter is included in Section 2.04.9- Attachment 10. Basically, prime farmland soils result in prime farmland land use when there is a dependable and adequate supply of water to allow the land to be irrigated to its potential. Generally, those soils which have a very high percentage of coarse fragments (greater than 35 percent by volume), very shallow bedrock (0 to 10 inches), and shallow ground water (less than 1 to 2 feet), have little suitable topsoil to be salvaged. No topsoil is available to be salvaged from existing roads, ponds, residences, or farmyards. The pre -mine soil survey (IRI, 1998) did not define any soil within the permit boundary as being "prime farmland soil". However, in February 2008, the NRCS stated that soil units 98A and 98E as mapped by IRI qualified as prime farmland soil (see Attachment 2.04.9 -10). Part of the reason for this reversal was due to a typographical error in the previous NRCS documentation. Therefore, Technical Revision 57 (TR -57) to the mine permit was submitted to the DRMS in March 2008 to address the changes in Prime Farmland and in the topsoil handling procedures. All mine operations in the areas designated "prime farmland soil' occurring from February 2008 forward conform to the proposed handling procedures for these soils. A second letter was issued by the NRCS on August 4 th of 2009 which provided a distinction between prime farmland soils and prime farmlands. Prime farmlands as a land use occurs when prime farmland soils have adequate and dependable supply of water and are economic to produce crops. Very small areas of prime farmland soil be not be economic to irrigate, therefore, they may not be classified as prime farmland. In early 2008, The Norwood office of the NRCS determined that the Begay, Barx and Darvey soil types (equivalent to the 98A and 98E soils in the permit area west of 2700 Road), met the qualifications of "Prime Farmland Soil' as defined by the USDA ( See letters from the NRCS in Attachment 2.04.9 -10). (Revised October 2009) 2.05.4(2)(d) -14