2010-05-17_REVISION - M1991079 - Laserfiche WebLink

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MULE FARM GRAVEL PIT EROSION REPAIR PLAN (TECHNICAL REVISION 4) INTRODUCTION This Technical Revision to the previously approved Mining and Reclamation Plan (M-1991-079) is triggered due to damaged caused by flooding of the Gunnison River during Spring of 2005. Specifically, the force of the river entering the mining excavation, through adjoining BLM property, created three erosional features in the southern portion of the permitted property. Mining activities commenced at the Mule Farm Gravel Pit in 1992. The area impacted by the 2005 flooding (southeast area of the permitted area) was reclaimed during 1998 and 1999. This reclaimed area had become stabilized by the successful growth of planted grasses. There were no visible signs of erosion within this area prior to the flooding. On or about May 20, 2005, the Gunnison River, which is adjacent to the south and southeast permit boundary, began to overtop its normal banks. The adjacent property to the west, owned by the Bureau of Land Management (BLM), has a crude "boat ramp" that is used by the public for take out of rafts, canoes, etc., when floating down the river. This boat ramp primarily consists of an unimproved depression that was cut through the historical river bank. This depression provided an avenue for the flood water to escape the river channel and enter the BLM property, ultimately impacting Elam's gravel pit. Flood waters continued flowing into the pit for approximately 6-days. During this 6-day period, there were three channels that were carved into the previously reclaimed and stabilized slope near the southeast portion of the pit. These channels were a result of the volume and velocity of the flood water entering the permitted property. It is important to note that the sediment from the erosion was captured by the pit. The overall mining plan and reclamation plan will remain unchanged from its original submission and subsequent approval in the early 1990's, including any subsequent revisions. This Technical Revision solely addresses the repair of damage caused by flood waters and any modifications directly necessitated by those repairs. BACKFILLING AND GRADING The eroded features will be backfilled with excess overburden material stockpiled on the eastern portion of the permitted site. In addition to the overburden material, any excess inert material removed from construction job sites around the Grand Junction area will be hauled and placed in the affected areas. Any imported inert material will be clean from any contaminates or items that may be M-1991-079 Revised May, 2010