INSPEC31383 - Laserfiche WebLink

Home Browse Search

(Page 21 MINE ID rt OR PROSPECTING ID ~ M-77-446 INSPECTION DATE 10-25-99 INSPECTOR'S INITIALS SSS OBSERVATIONS This was a routine inspection, conducted as part of the Divisions monitoring plan for permitted mine sites in Colorado. The site is nearly mined out. The County indicates that they have approximately one year of mining left before the gravel resource is gone. The actual mining of the site is done by operators who win a bidding process for ~:onducting the work. The latest contracts that the County puts out for bid include a provision for the operator to perform reclamation of mined out areas, in the form of backfilling and grading. Portions of the south and east pit embankments Piave been backfilled. The west side of the pit holds some of the stockpiled topsoil. The remaining gravel resource is located in the southwest corner of the site. The north boundary of the site lies adjacent to the Gosney and Sons Ignacio Pit No. 2. In an amendment to this application, a buffer zone on this northern end was removed so that the floor of this pit could adjoin the floor of tie Gosney pit, at the same elevation, with no berm in between. Currently, the floor of this pit appears to be a few feet lower than the adjacent Gosney pit, and a small berm remains between the pits. The County will need to update this permit, through the technical revision process, to clarify how this boundary will be reclaimed. It is recommended that the berm Ire removed and that material used to fill the pit slope and bring it to a shallow grade of 5:1 or less. There are some piles of earth, rotomilled asphalt, and some larger chunks of asphalt that have apparently been imported and dumped on site. These piles were dumped against the side of one of the topsoil stockpiles, potentially contaminating this resource. The county will need to provide a notice of importation of inert fill for the earthen m:~terial that has been imported. Rule 3.1.519) specifies the information that must be included in this notice. If additional materials are imported to the site, the County will need to avoid dumping near the topsoil resource, and will need to submit the aforementioned notice prior to importing the material. The materials already imported will need to be removed from the topsoil stockpile. All inert material can be used as backfill on site. Any toxic material will need to be removed from the site and properly disposed of. The topsoil stockpiles on the west side of the site are covered with Canada and musk thistle. This problem was also reported in the last inspection. It did not appear that any of the thistle flower heads were drooping, indicating that they probably had not been sprayed with herbicide. The county has indicated that all of their gravel pits are n their weed control plan schedule. Significant progress toward controlling the noxious weeds on site must be evident within three years. The county is encouraged to indicate, on the annual reports for each mine site, any weed control efforts that are taken. It does not appear that an adequate amount of topsoil exists in the west boundary stockpiles to replaces 6-12 inches across the site as required by the approved reclamation plan. The Couniy will need to determine if enough topsoil does exist on site for reclamation. If enough exists, please indicate where it is located. If not enough is located on site, please indicate where the shortfall of topsoil will be obtained from. The east permit boundary is occupied by a large stockpile of material, with a road on top. The pile appears to consist of an upper section of overburden. It may be placed over of a topsoil stockpile, as evidenced by the mature vegetation established on the lower outside slope of this pile. In places, the overburden has been pushed over the vegetated outside edge of the stockpile, and has then been eroded by the high rainfall this past summer. Some of the sediment flowed onto, and covered the perimeter road that is utilized by local gas companies. The County will need to install sediment control for this stockpile to prevent additional erosion and sedimentation and remove the sedimentation feature:; from the perimeter road.. If the base of this pile does consist of a topsoil stockpile, then permit conditions, specifying th~3t it was to be kept separate from the overburden and be protected from compaction and erosion, have not been met. Tfie County will need to take measures to prevent additional erosion, compaction and contamination of this resource. The mine identification sign is in compliance, as well as the permit boundary markers. However, the permit boundary is hard to identify and should be marked with an adequate amount of additional markers so it is readily identifiable.