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~. Colorado Yampa Coal 29588 Routt County Road #27, Oak Creek, CO 80467 • Telephone (303) 879-3800 RE~E~VED October 18, 1984 ncT 2 ; ~,~R~ MINED (qNp aECLAMATIpN DIVIS1{JN Colo. Dept, of f9atural RESOUrces Ms. Anne Baldridge Colorado Mined Land Reclamation Division 423 Centennial Building 1313 Sherman Street Denver, Colorado 80203 Re: llear Ms. Baldridge: this would not necessarily be the case. Mass Movement on Area 1; Permit 79-177 During the spring of 1984, three areas of mass movement were noted on Area 1. The rnass movement sites are located adjacent to springs near the bottom of the hillslope. The springs in the area can be attributed to a combination of effects: 1) greater infiltration capacity from the effects of mining, and 2) abnormally high precipitation in 1983 and 1984. Due to the high precipitation years the springs are currently flowing on a year round basis; in normal precipitation years rock drains in the saturated slump areas to dewater the site. The mass movement sites are small in size and were probably caused by saturation of the graded spoil and underlying strata. Due to the small size of the slumps and a-typical climatic events, the Colorado Yampa Coal Company is not planning to regrade the site at this point in time. The slump areas will continue to be monitored to determine if a potential exists for future mass movement. if it is determined that there is a potential for future mass movement CYCC will install Rock drains will be installed by utilizing a backhoe to dig a core trench in the area of saturation. The core trench would be four feet in depth and extend at a 1.5% slope until it daylighted on a stable site (Figure 1). The core trench would then be filled with eight inch minus rock up to 6 inches from the surface. Topsoil would then be replaced and the area revegetated. • • ^~~~ ~iiiiiiinii~ iii =.. ,, _~;