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Memo to Erica Crosby Roadside North Portal Subsidence page 2. and aerial photos which you provided I would concur with Roadside's observation that there are no structures. However, Jerry Creek, Coal Creek, and their alluvial aquifers should qualify as a renewable resource lands. As such the operator should have prepared a subsidence inventory and a control plan to prevent damage to Jerry Creek, Coal Creek and their alluvial aquifers. Under the hydrology portions of our regulations, the operator should also have addressed possible impacts to Jerry Creek within the statement of probable hydrologic consequences (PHC). Based upon our experience with Rapid Creek over the South Portal workings of the Roadside Mine, its logical to believe that this problem can be addressed adequately. Further, since you have not provided me any of the hydrologic portions of the permit revision, this required treatment may have been accomplished. In my opinion the operator should be directed to provide a subsidence "survey" (inventory & prediction) addressing the potential consequences of subsidence for Jerry Creek and Coal Creek and their alluvial aquifers, if they exist. Assuming Jerry Creek and Coal Creek can be demonstrated to be hydraulically similar to Rapid Creek the experience with subsidence impacts to Rapid Creek would be applicable. The subsidence control plan for Rapid Creek consisted of minimal mechanical subsidence monitoring of the channel area, periodic visual inspection, repair of any cracks in the immediate channel, and an inflow survey of the underground workings. The mechanical subsidence monitoring would probably consist of a few carefully chosen monument locations immediately adjacent to the channel of Jerry Creek over Uriit 1 in Sections 20 and 21 and a few monuments immediately adjacent to the channel of Coal Creek, west of the waste piles, above Unit 1 in Section 29. I assume the ground water hydrologic consequences of any related alluvial aquifers could tie addressed with several alluvial monitoring wells, and any surface water hydrology concerns could be satisfied with upgrade and downgrade surface flow weirs. In this manner the questions of diversion of water due to subsidence impact could be addressed. The visual inspections would consist of a semi- annual walking inspection of the two channels. The mine inflow survey is a simple mapping and recording of localized inflows and sump accumulation.