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8/5(2014 State.co.us E)ecub\e Branch Mail -RE: New Elk Mine, C1981012, TR68, Second adequacyreuew = 11111111111111111h, 6';' R ; OF STATE quCOLORADO RE: New Elk Mine, C1981012, TR68, Second adequacy review kent @gorhamenergyconsultants.com < kent @gorhamenergyconsultants.com> Fri, Aug 1, 2014 at 4:08 PM To: "Simmons - DNR, Leigh" <leigh. Simmons @state. co. us >, Jim Stark - DNR <jim.stark @state.co.us> Cc: Ron Thompson <ronthompson @newelkcoal.com >, Louis Head <Ihead @newelkcoal.com >, Alysha Hernandez - DNR <alysha.hemandez @state.co.us> Thank you Leigh and Jim for taking the time to meet with me yesterday. The post - meeting notes reflect accurately our various discussions. Regarding the CCY, BCY, and LCY discussions, I offer the following opinion, based on those discussions and the current New Elk RCE (revised 2/13/2013). For example, for common earth, typical soil volume conversion factors for the initial bank (BCY) condition of 100 would be multiply bank times 1.25 to convert to loose (LCY) and multiply bank times .9 to covert to compacted (CCY). These conversion factors vary by material. For New Elk topsoil, we agreed that a factor of about 122 (or 22% swell) is reasonable. When the amount of topsoil thickness is investigated over and area to be disturbed, the estimated topsoil volume lying in it's native state is correctly described in BCY. Once this topsoil is excavated for transport, it is swelled and referred to by volume in LCY. If that volume of topsoil is then stockpiled, it does undergo some amount of compaction, and likely becoming a smaller volume, possibly close to the original volume in BCY. Possibly in a rare case, the volume would be compacted to a volume less than the bank volume, which may be close to the table value of the material in CCY. However, this condition is likely rare for topsoil. Therefore we agreed that a stockpile in storage generally is a volume close to the original bank volume determined from the topsoil thickness and area as the topsoil was found in the native state and would be referenced in the RCE topsoil task sheets in BCY. This way, the topsoil volume as originally calculated and estimated by the operator in the permit application remains relatively accurate and is not unfairly of inaccurately modified through unnecessary swell that would occur if one coverts the volume based on accepted science from CCY to LCY, which would result in a large amount of swell based on table values. I point this out simply because all of the topsoil sheets for New Elk show initial volumes of topsoil in CCY and then convert to loose volumes in LCY. Two problems seem to result: First, the initial volume should be in BCY (not CCY) and second, the swell factor of 1.125 should likely be closer to 1.20. Or said another way, if the volume is truly CCY and being converted to LCY, a conversion factor (swell) of nearly 1.35 should be used! As I mentioned, successfully calculating an accurate topsoil balance at the mine is heavily dependent on everyone using the same understanding, terminology and accepted table values. Once this is accomplished, it is a simple matter of math to determine the correct volumes for the RCE. To summarize this issue, topsoil will be originally estimated via permitting actions in BCY, and if is managed by nominal operations by stockpiling as is typical over the life of the mine, it will be referred to in the RCE task sheets as the originally volume in stockpile (BCY) and swelled to LCY by standard table values for moist earth or soil upon lay -down for final reclamation. In only rare cases would the volume be reduced from BCY to CCY by compaction. And finally, it is incorrect to https:Hmail.g oog le.corr✓mai 1 /u/01?ui =2&i IFe29129fcb5&view=pt& search= inbox&th= 147939de4l788599 &sim1= 147939de41788599 1/5