HYDRO30049 - Laserfiche WebLink

Home Browse Search

~PECTION REPORT ,~y;• Ao8 R: M4y, ~.~.,tproj~i Engineer IVED ~~: ~x (fit ,, p,~ January 14, 2001 F E B ~ 2 2001 ~: t% ~6_t~ 1Fr~,se~ttr~ation ponds and their embankments and ot7N~ of Mlrrera~s s ceoloey ~~ ~_ ,' 'ftj{~ covered west pond is shown in photogreph 1. As I6t t~gft4, ~ ditch entering the pond is undergoing erosion and ' .. retl. Thq Raft pond appears in good condition. ,. y ~ S} ~~t~0aaf i(Ir1p CoaC Mirtd% Htllpirilr, Colorado Q,~jnaoe Ditches: The eastside and westside drainage channels appear in good general condition. Photograph 2 shows a newly armored ditch that runs down the north elde of the waste pile. Erosion in this ditch had been indicated as a problem in previous r+sports. The rock-lined channel appears to have an adequate capacity and should resist erosion. All other ditches and structures were inspected and appear in good operating condition. Photographs 3 and 4 show the mine yard in two directions. There are no apparent drainage problems. All drainage features have been constructed and are operating as stated in the drainage plan submitted to the Division of Minerals and Geology. Coal Waste Pile: There are no visible signs of structural instability on the waste pile. The pile continues to grow as shown in photograph 5. A new road has been constructed above the north side of the pile (photograph 5) to provide access to the upper valley as the pile grows. Photograph 6 was taken at the bottom of the waste pile looking along the haul road that circles the coal storage pile under the conveyor. The toe of the waste pile face has been cut to a steep angle, apparently to make more room for the haul road. The cut can be clearly seen on left side of this photo. This oversteepening of the face could result in instability. This area should be regraded the design slope of 3:1 and compacted to 90% proctor. The top of the pile appears to conform to the design geometry however the top of the face should be checked to assure a slope of 3:1 or less. It is important that the waste material 6e placed in lifts not to exceed 12" to 18" and that compaction results in the density stated in the design report. It is not possible to determine this by visual inspection and therefore the density should be periodically checked by measurement. Rill formation on the front face of the waste pile is unchanged from the last inspection. The highwall and other slopes at the site appear stable. It is recommended that the upstream end of the water pile underdrain be located and marked. As the pile grow this task will become more difficu{ty. F,ccept for the items mentioned above the fill on the waste pile has been constructed as specified in the design approved by the Division of Minerals and Geology.