Laserfiche WebLink
III. COMMENTS -COMPLIANCE <br />Below are comments on the inspection. The comments include discussion of observations made <br />during the inspection. Comments also describe any enforcement actions taken during the inspection <br />and the facts or evidence supporting the enforcement action. <br />patches of the noxious species Russian knapweed were noted (for which continued control <br />measures are necessary). <br />Vegetation on the eastern half of the northern "leg" of Mining Area No. 1 differs markedly from <br />that on the remainder of the area. Cheatgrass is notably more abundant, with lower cover and <br />diversity of perennial grasses. Patches of mature Wyoming big sage have established from <br />volunteer in several locations. This area has been the primary focus of Russian knapweed <br />control efforts, and several locations where large patches had been sprayed in the past year <br />were evident, with a few remnant live knapweed plants noted along the margins of the sprayed <br />areas. One patch of robust knapweed approximately 10' in diameter was observed. Continued <br />knapweed spraying will be necessary. The lower cover of seeded perennial grasses and higher <br />component of volunteer and weedy species noted in this portion of Mining Area No. 1 may be <br />due to differences in the reclamation sequence. According to Annual Reclamation Reports, this <br />area was topsoiled in 1992, while the remainder was topsoiled in 1993. Mr. Andrews recalled <br />that in 1992, topsoil was "live- hauled" rather than stockpiled. Perhaps the most critical <br />difference is that the area topsoiled in 1992 was not seeded with the permanent rangeland mix <br />until the fall of 1993. The intervening winter saw exceptionally heavy snows across the region, <br />and the abundance of moisture, combined with the seeds naturally occurring in the live - hauled <br />topsoil, served to give big sagebrush and undesirable species, such as cheatgrass and <br />knapweed, a head start on those species seeded later. <br />Across the entirety of the Mining Area No. 1, a high percentage of the mature four -wing saltbush <br />shrubs were in poor condition, with a high percentage of leafless branches, possibly due to lower <br />than normal winter temperatures. Although vegetative cover and composition varied across the <br />site, the extent of vegetative cover, combined with the high sand content of surface soils, and <br />low slope gradients, appears to be sufficient to control erosion. No rills or gullies, or other <br />indicators of erosion were noted, and it would appear that erosion and sedimentation from the <br />reclaimed areas is very minimal. <br />Mining Area No. 3 <br />Depths of topsoil replacement for Mining Area No. 3 have not been previously reported by HCC. <br />Topsoil depths were measured at six locations during the inspection. Values ranged from 7" to <br />16 ", with an average of 12.5 ". The permit currently requires a 16" replacement depth, but that <br />value was determined by averaging the resource available for a larger area. The operator has <br />been requested to provide an assessment of the average soil thickness that would have been <br />available for salvage, based on pre - mining assessment and the acreage of specific soil types <br />actually disturbed within Mining Area #3. Disturbance at Mining Area No. 3 was limited to only <br />9.9 acres. <br />Perennial vegetative cover appears to be lower than in Mining Area #11, with a higher <br />component of bare ground and weedy annuals, particularly Russian thistle, as well as scattered <br />patches of cheatgrass. Needle- and - thread grass was almost non - existent at this location, but <br />there were some zones of blue grama and indian rice grass, l=our -wing saltbush is present at low <br />Hamilton Mine G -1991 -078 3- Jun -2010 <br />-2- <br />