2008-05-05_HYDROLOGY - C1991078 (2)

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HONEYWOOD COAL COMPANY HAMILTON MINE IMPOUNDMENT YEARLY INSPECTION In accordance with Rule 4.05.9(14), all impoundments shall be inspected at least yearly to determine if the impoundment has been maintained as designed, and in accordance with the approved plan and the applicable regulations. This yearly inspection is for the impoundments located at the Hamilton Mine. On April 25, 2008, I performed the required yearly inspections. I, J. E. Stover, have a wide variety experience in the design and construction of earth fill embankments. With regard to Pond A, nothing was observed during the inspection that would indicate the pond has a potential for failure. There was no appearance of erosion, instability, structural weakness or other hazardous conditions. There are no required monitoring procedures or-instrumentation other than quarterly_and -yearly monitoring. There are no _ aspects which might affect stability and there is no required maintenance. There was no discharge from the pond. Pond B had some pooling of water near the outlet of the primary spillway. The origin of this water appears to be minor seepage through the embankment. There is moss growing in the pool so the embankment has been seeping for some time. There is a risk of embankment failure from this seepage should it accelerate. The local representative must closely monitor this seepage to assure it does not increase. The pond should be dewatered to assure it has capacity to contain the run-off from a 10- year precipitation event and to eliminate the risk of embankment instabiiity. There was no discharge from the pond at the time of the inspection. Pond A was dry. Pond A is located north of Mining Area No 1. The design of Pond A is shown on drawing 117-A, revised 3-26-92. Pond B had a pool of water standing about two feet below the level of the emergency spillway at elevation 5818. Pond B is located east of Mining Area No. 1. The design of Pond B is shown on drawing 117 B, revised 11-4-92. The impoundments have the following capacities based on the original pond certification dated May 5, 1992 prepared by the undersigned: IMPOUNDMENT CAPACITIES -ACRE FEET Water Sediment Total Pond A Pond B 2.16 8.07 0.21 0.55 2.37 8.62 Note: The sediment capacity of the ponds may be less than shown in the table because of interim sediment accumulation.