2002-07-08_GENERAL DOCUMENTS - M2002004 (4)

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4 COLORADO SCHOOL OF MINES RESEARCH INSTITUTE PLOT DESIGN AND CONSTRUCTION Utilizing a wedge concept first described by Power, Ries, and Sandoval (1976), plots were constructed as shown in Figure 1. However, plot length was increased from 15 m to 33 m for the plot located at the Cordero mine and for the plot constructed at the Belle Ayr mine in 1980. Plot width was 6.1 m with a I- to 1.5 -m buffer area around the perimeter. Efforts were made to locate plots in relatively fresh spoil (0 to 3 years old) which was considered, by mine person- nel, to be representative of the spoil being produced at that location. Most plots were located on recontoured spoil surfaces which were being prepared for soil application. With few exceptions, a bulldozer was used to cut the wedge into the spoil. The establishment of a smooth, uniform grade on the sloping spoil surface was considered a key component of plot construction. Most plots were constructed in the fall to minimize the possibility of compaction. Soil was obtained from existing "topsoil" stockpiles and transported to the plot by scraper or truck. At all plots, the soil used was considered to be typical of the soil available for and used in reclamation. Soil was applied to the spoil wedge using a bull- dozer, front -end loader, or scraper; soil application was conducted at a time and in a manner that minimized compaction in excess of that required to prevent more than 5 cm of settling. Either a grader or bulldozer was used to smooth the plot surface following construction. If excessive compaction in the spoil zone of the plot was suspected, that area was ripped to a 30 -cm depth. A dike was con- structed around the perimeter of some plots to prevent water entry from adjacent areas. The plot was then fenced to preclude grazing by the larger herbivores. In certain locations, 2.5 cm mesh wire was used to discourage rabbits from enter- ing the plot. Finally, a sign was placed at each plot describing the purpose of the plot and requesting that the plot not be disturbed. To provide access for a moisture - density probe, a motor - driven auger was used to drill access holes 1.52 m deep. Access holes were drilled where no soil was applied to the plot and where approximately 40, 80, and 152 cm of soil were applied to the spoil surface. Aluminum irrigation pipe was inserted in the 5 -cm- diameter holes, and the exposed portion of the pipe was capped. Plot locations, construction dates, and initial seeding dates are as follows: Location Glenrock, Wyoming Wright, Wyoming Wright, Wyoming Gillette, Wyoming Gillette, Wyoming Gillette, Wyoming Gillette, Wyoming Sheridan, Wyoming Hardin, Montana Colstrip, Montana Colstrip, Montana Center, North Dakota Noonan, North Dakota Mine METHODS Dave Johnston Black Thunder Jacobs Ranch Cordero Belle Ayr Wyodak Rawhide Big Horn* Westmoreland- Western Energy* Big Sky* Baukol - Noonan* Baukol - Noonan* Plots located north of Gillette, Wyoming. Construction Date Spring of 1977 Fall of 1978 Fall of 1977 Fall of 1979 Spring of 1977 Spring of 1977 Fall of 1978 Fall of 1976 Spring of 1977 Fall of 1977 Spring of 1977 Fall of 1976 Fall of 1976 Seeding Date Spring of 1977 Fall of 1978 Fall of 1977 Fall of 1979 Spring of 1977 Spring of 1977 Fall of 1978 Spring of 1977 Spring of 1977 Fall of 1977 Spring of 1977 Spring of 1977 Spring of 1977