2009-07-15_REPORT - M1988044 (2)

Home Browse Search

MINING ACTIVITY IN THE LAST YEAR: 1. Depth of mining - In the last year, mining depths were extremely variable due to the spotty and highly variable configuration of the remaining sand. In many instances, mining depth was quite deep, but also very large amounts of overburden and waste (wash fines) were generated. The waste is mostly located near the plant and comes from pond cleanings. Soils were exceptionally deep in some places which generated large volumes of soil for backfilling. Much of this soil is from deeper horizons and therefore of limited value for reclamation uses other than for filling. All mining was in compliance with the depth requirements. 2. Backfilling - Backfilling of mined areas has increased tremendously in the last year as a result of reaching the edges of deposits. As described in the plan, mining continues in a deposit until the mining limit is reached or the deposit ends. Many of the areas that were previously mined had no remaining sand present and were completely backfilled and graded. Most of the backfilling occurred on the high area of the upland and to the south of the 2008 seeded land. At this time, there are no longer any extensive areas of working faces or highwalls. They have all been reduced and either completely reclaimed or backfilled and rough graded. A. Depth of backfilling - With the large amount of overburden and soil as well as waste from processing the low grade sand that has been mined recently, backfilling was so great in many areas not only did the original topographic configuration essentially return, but the elevation differences with the original were also small. Normally, there would be more difference in elevation, but with so much low grade sand being removed, not a great deal of volume difference occurred. As a result, when all the useless material is replaced it results in almost a restoration of the original surface form. B. Material used in backfilling - Most of the backfilling done has used overburden and subsoils stripped from the site where the filling is being done or at least sites that were near enough to the backfilling that it is still considered to be original material. This is consistent with the method of operation described in the plans. Other sources of material include wash fines from processing plant pond cleaning. C. Maximum, minimum, and average slopes - Finished slopes in all the backfilled, graded and topsoiled areas are rarely even close to the 5:1 limit. Most are in the 7:1 to 15:1 or less steep range. The average for backfilled areas in the last year is probably about 20:1 with many areas nearly level and steeper slopes being tip to 5:1 over small areas. Even backfilled and rough graded areas do not have slopes steeper than 3:1, except over small distances and there are large quantities of overburden and soil to be moved into those areas before they are completed. D. Deviation from original elevation for new backfilled land - As mentioned above, in areas reclaimed this year, the deviations from the original elevation amounts to only a few feet and when compared to the original topography map it is hard to even Status report for 2009 due July 15, 2009 Page 7 of 10