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MINING PLAN <br /> sediment basin where a conveyor deposits sand mined east of Academy. Th processing plant area <br /> was removed from the permit in 2006. <br /> NATURE OF THE DEPOSIT TO BE MINED <br /> As is true in most mining situations, until at least the rudimentary details of the nature of the <br /> material to be mined is known it is very difficult to describe how the material will be mined. <br /> Sometimes, the nature of the deposit is readily evident, especially when the material is exposed in <br /> cliffs as solid rock. But with many aggregate sources such as sand and gravel, the structure of the <br /> deposit is not evident from the surface and often there are no cuts into the deposit that can be <br /> observed to obtain even rudimentary concepts of its nature. Often drilling(deeper deposits) or <br /> exploratory pits (shallow deposits) are used to obtain some information regarding the deposit so a <br /> mining plan can be developed. The long history of mining sand at the Daniels Pit has provided <br /> information regarding this deposit. Mining faces often display the full range of textures and <br /> structures in the deposit. <br /> The sand deposit was formed over a very long time period primarily during the last few <br /> hundred thousand years and mostly during and after the most recent ice age. Most of this sand <br /> deposit is probably younger than 20,000 years. It is possible the deposit may include sand that has <br /> been deposited over the last million years,but it is more likely that during interglacial periods <br /> previous sand, if deposited at all,was mostly removed by erosion and new sand deposited. Thus, <br /> most of the sand in this deposit probably comes from the last ice age. <br /> During the melting of the ice in the glaciers on the north side of Pikes Peak, considerable <br /> sand was carried onto the plains by swollen streams. Runoff from the Palmer Divide also flowed <br /> through this area and those streams carried fine sands from those granite deposits. In addition, it is <br /> likely that the high plains to the east had exposed dune fields and strong winds carried very fine sand <br /> into this area. This may have been particularly true about 5,000 years ago during a period of intense <br /> and prolonged drought, sometimes referred to as the Xerithermic Period, that lasted 100 years or <br /> more. <br /> The lower portions of the deposit generally contains the more coarse sands deposited by <br /> alluvial processes. These sands probably came from more local sources during or shortly after peak <br /> melting of ice and snow as the ice age drew to a close and the current interglacial period began to <br /> take hold. But mixed with these sands are finer sands that either blew into the area from the north or <br /> east or were separated from the coarse sands by strong winds and deposited into drifts alongside <br /> meandering streams. Subsequent stream flow may have partially removed these sands and mixed <br /> them back into the coarse sands or the stream flow may have covered the fine sands with more <br /> coarse material producing pockets of fine sands surrounded by coarse sand. <br /> Daniels Sand Pit Amendment (2008) Exhibit D Page 2 of 28 <br />