_INSPECTION - C1981012 (48) - Laserfiche WebLink

Home Browse Search

West Portal Core House The West Portal Core House is a former single building at the West Mine. The 1 acre area of disturbance associated with demolition of the building was reclaimed in 2006. A sediment demonstration in the form of modeling was found in Exhibit 19, part 5 Miscellaneous Drainage Supplement. The area is also mentioned in the Stormwater Management Plan in Exhibit 22 of the approved permit under Part 2, item #11 and in the table included in Part 5, item b. The area is shown as an SAE on Map 12, West Portal Area — Roads, Utilities, and Facilities 3/24/2011 of the approved PAP. The flat reclaimed area was found well vegetated with grasses and forbs. Three or four small holes or craters were noted on the reclaimed area. Each hole was approximately 18 inches to two feet in diameter and no more than 3 feet deep. Each seemed to be associated with a small piece of metal or concrete remnant of the structure. These features did not appear to be subsidence related or caused by with storm runoff from the SAE itself. They are likely a result of voids and uneven settlement of the regarded area of the building. The operator should fill these small holes with topsoil material and reseed. East Portal Water Tanks The East Portal Water Tanks Area (see photographs) is a current, active SAE area at the East Mine. Due to recent permitting, the single area is now two small areas, the original tank pad and a lower area along the access road to the pad. Both areas are upstream of a clean water diversion and do not report to a sediment pond. The combined disturbed area of the two areas is approximately one acre. A sediment demonstration in the form of modeling was found in Exhibit 19, part 5 Miscellaneous Drainage Supplement. The area is also mentioned in the Stormwater Management Plan in Exhibit 22 of the approved permit under Part 2, item #12 and in the table included in Part 5, item b. The area is shown as an SAE on Map 11, East Portal — Facilities, 4/22/2011 of the approved PAP. Modeling and documentation included in the PAP call for four inches of gravel for traffic areas, a swale at the access road entrance to retain runoff on the pads, and revegetation and/or mulch of the non-traffic areas. Field inspection revealed the operator is using a berm and straw bales along the outslope of the upper water tank pad area. Gravel in an undetermined depth was noted in most traffic areas. Some disturbance of the revegetated areas has occurred recently due to current activities associated with water system improvements at the mine. The swale or berm at the entrance to the pad area should be improved when the new 400,000 gallon water tank installation has been completed. Revegetation or mulch in accordance with the approved plan should also be completed when construction ends. The lower pad area was recently used to conduct emergency drilling activities associated with underground mining towards the East Portal Fan. This pad has temporarily blocked the clean water diversion ditch. Identical measures for this pad site should be implemented once the 25,000 gallon water tank is constructed at this site. Standard alternative sediment control measures should be used during any construction activities at these SAE's before final SAE sediment measures are established. No erosion or evidence of instability was noted at either tank area. West Portal Pumphouse Area The West Portal Pumphouse and access road to this site is the former location a small pumphouse to supply mine water from the Purgatoire River alluvium for mining activities at the West Mine. The area of the site and the access to the site is about 1.72 acres. The area was reclaimed and revegetated in 2005. A sediment demonstration in the form of modeling was 5