2008-02-19_GENERAL DOCUMENTS - C1981047

Home Browse Search

s Approximately 10,000 cubic yards of material were removed from this site to be used as backfill and as a growth media for the mine bench. The large rocks and steep slopes prohibited initial salvage of growth media. But, soil sampling for fertility, salinity, and texture was done on the reclaimed areas in order to amend the soil to assure revegetation success. Approximate final contours of both the mine bench and the hillside borrow area are shown in Exhibit F-2 of the permia application. The mine bench backfill was placed on approximately a 15 degree slope from the invert of the drainage ditch on the top of the mine bench, which left an approximate 35-foot highvrall. The hillside borrow area was not excavated to a slope greater than 25 degrees. The stabilization of the slope below the mine bench was done in 1985 in accordance with the Mine Bench Stabilization Project. The mine bench is monitored quarterly for stability and water level. The bench has shown to be relati~rely stable with the exception of a small slump in 1988 and 1989. 'T'hese were subsequently repaired and reseeded. The b~ackfilling required upon final reclamation includes two sediment ponds and the light-use road. However, Oxbow Mining, the fee surface owner of the disturbed land, requested that the light use road be retained. XI. Reve eg tati~~n Blue Ribbon's revegetation plan can be found in Section 2.05.3, beginning on page 111 in the penmi~t application. Revegetation areas are shown in Exhibit Q and Exhibit E shows the vegetation communities. The majority of the revegetation work was completed during initial reclamation in 1986. Areas still to be revegetated include the two sediment ponds, associated ditches, and the tight-use road. As mentioned previously, Oxbow Mining, the fee surface owner ofthe disturbed land, requested that the light use road be retained. Two communities have been re-established on the disturbed area. A grassland community was re-established on the uplands and slopes away from Hubbard Creek, and a riparian community along the creek and flat valley bottom. After the slopes in the grassland community were prepared for planting, grass, forb and shrub seeds and necessary amendments were broadcast and then the area was mulched and crimped. Revel;etation of the riparian community was accomplished once the surface was graded, scarified, and plant growth medium distributed. The revegetation included an approved seed mix and n•ansplanting and seeding of clustered shrubs. The shrubs were initially planted with the seed srnd the necessary soil amendments. Because the riparian area is relatively level, a straw mulch was applied at a rate of 1,500 to 2,000 Ibs/acre and mechanically crimped and netted. Pursuant to Rule 4.15.7(2)(d)(vi), the operator had originally requested that the Division set stand~~rds for revegetation success based upon local environmental conditions and available data for similar sites. The standards recommended by the Division were accepted by the applicant. 28