Laserfiche WebLink
CommenUResponses, TR-62 <br />Page 2 <br />2. Current Table 2.05-1, "Topsoil Schedule for Mining Area", was approved by TR-42 in <br />1997. The table provides soil balance projections for the permit terms ending in 2002, <br />2007, and 2013. More detailed projected soil balance information is provided on an <br />annual basis for 1997 through 2002, on current Table 2.05-2. The projections indicate <br />that the volume of soil to be salvaged would significantly exceed the volume necessary to <br />replace the 1.5 feet average replacement thickness, and further indicate that the "excess" <br />volume would be placed in stockpile. <br />The current volume of stockpiled soil indicated on revised Table 2.05-1, provided with <br />TR-62, is approximately 1 million cubic yards less than that projected on the current <br />version of the table. <br />Please provide a description and summary of any actual operational data collected <br />on an annual or periodic basis during the previous and current permit terms, <br />corresponding to the projections of current Tables 2.05-1 and 2.05-2. Comparison <br />of "actual" versus "projected" removal acreages and volumes, replacement acreages <br />and volumes, and stockpiled volumes, would provide some insight into the reasons <br />for such a -arge discrepancy in the cumulative volume of topsoil in stockpile. <br />Response: In order to do a historical analysis, annual topsoil stockpile volumes, annual <br />disturbance boundaries and reclamation amounts would all have to be researched. <br />While this could be done, it represents a significant amount of work to research and <br />verify this historic data, most of which is only available on old drawings and tables <br />provided in annual reports. Regardless of the reasons, this analysis of historical data <br />would not change the situation in the field today. <br />Upon a closer analysis of the old versions of Table 2.05-1 and Table 2.05-2 as <br />presented in the current permit, apparent discrepancies exist between these two tables. <br />For example, the 1997-2002 period shows that 3.9 million yards will be removed, while <br />the second table shows that 2.8 million yards will be removed. This corresponds to a <br />salvage depth of 29 inches for the first table and 18 inches for the second table. In <br />reality, much less topsoil was actually salvaged. Thus, it is not surprising that this table <br />indicates more topsoil that the quantities provided with TR-62. <br />It can also be seen that the volumes provided on the second table are simply factored <br />based on the acres and an assumed depth of 18.0 inches, not based on the premining <br />soil survey. <br />The updated Table 2.05-1 as submitted herein provides the most accurate analysis <br />available for the mine as of December, 2005. The currently approved mine plan is in a <br />very mature phase. For example, only about 65 acres of additional stripping remain for <br />the West Pit. Depending on future mine plans, the area of future topsoil stripping ranges <br />from about 65 acres to 277 acres. In any event, the amount of future stripping is quite <br />limited. <br />The TR-62 proposed version of Table 2.05-1 is a survey based topsoil balance for a <br />particular point in time (October, 2005). If the existing disturbance were to be reclaimed <br />with the available soil in stockpile, the table would provide sufficient information for <br />planning purposes. However, in actuality, it appears that surface disturbance is projected <br />