2012-12-20_GENERAL DOCUMENTS - C1981038

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application /permit revision and the 1986 permit revision and has determined that there are no sites within the permit area currently listed in the National Register of Historic Places. Surveys classified seven of these sites as eligible for the National Register pending further investigation. None of the seven were disturbed by development activities, and none were undermined. The Roatcap Game Trail Site (5DT 271) was excavated in late 1986 to ensure that increased access in the East Roatcap drainage would not result in vandalism. Several of the other sites have a very limited potential for subsidence damage, as they are found on the margins of the angle of draw. Climatological Information and Air Resources - Rules 2.04.8, 2.05.4(2)(h), 2.05.6(1), 4.17 Climatological documentation is presented in Section 2.04 of Volume 1 and in the Climatology and Wind Direction Appendix, Volume 9. BRL has also provided copies of all emissions permits from the Colorado Department of Public Health and Environment, in Volume 9. Evaporation pan monitoring data are summarized in the Annual Hydrology Reports. Climatological data for the North Fork region is available from Paonia, three (3) miles due south and 1,500 feet lower in elevation than the mine site. The average annual temperature is 49.0 °F at Paonia, with an average monthly mean of 24.5 °F in January and 71.9 °F in July. At Paonia, the annual precipitation is 8 to 15 inches. The local climate of the North Fork area is strongly influenced by microclimatic features - slope aspect, elevation, soil type, soil moisture content and vegetation. The steepness of the terrain, together with the type and amount of vegetation, orientation and range of elevation, are the major controls of the diurnal wind patterns. The shape and orientation of the North Fork valley is such that the drainage (or katabatic) flow is the dominant flow for most hours of the day. Prevailing winds are from the south - southeast, with wind speeds of ten (10) miles per hour occurring in June. Below Paonia, the wind speed appears to decrease sharply as the air spreads over the lower valley. Because of this strong drainage wind, frost pockets are not allowed to form, thus creating a favorable microclimate for fruit tree farming. Geology - Rules 2.04.5 and 2.04.6(2) Information on local and regional geology can be found in Section 2.04.6 of Volume 1. Maps 2 -1, 2 -2, 2 -7, 2 -8, 2 -11, 2 -12 and 6A -8 identify pertinent geologic features. Waste rock geochemical analyses can be found in Volume 6A. BRL has mined the D seam of the Upper Coal member of the Mesaverde Formation. The seam ranges in thickness from 2 to 21 feet in the permit area, with one split ranging in thickness from 151/2 feet to several inches. The coal dips 4 °to 7° to the northeast. Two high- angle, normal fault zones are found in the area with displacement ranging between 1 and 50 feet (Map 2 -8). The earliest fault system trends N65 °E and dips 70° to 80° with displacements of 2 to 6 feet. The other fault system trends N35 °W and dip 70° to 80 °to the northeast. The geology is further modified in the northeast corner of Lease C -37210 where coked coal gives evidence of igneous activity associated with the Miocene Iron Point pluton. The Somerset Coal Field lies on the southeast margin of the Piceance Basin and just south of Grand Mesa. The sedimentary strata exposed in the Somerset Coal Field dip at 3° to 5° to the north and northeast, and range in age from late Cretaceous to early Tertiary. Coal is produced from the Mesaverde Formation, a 2500- foot -thick sequence of sandstone, shale and coals overlain by the Ohio Creek conglomerate and underlain by the Mancos Shale. The Mesaverde Page 7 of 42