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TRAPPER MINE RESPONSE TO PR-1 ADEQUACY RESPONSE DOCUMENT May, 1987 4. Surface Water and Sediment Control The sediment control plan presented is very general. The following spe- cifics of the sediment control system are needed: 1. Acreages draining to each pond. 2. Condition of the land draining to each pond, i.e. reclaimed, pit top- soil removed. 3. Volumes or routing of water resulting from the 10-year, 24-hour event. 4. Sediment generated from the area. 5. Peak flows resulting from a 25-year event. Response Soon-to-be submitted TR-36, Construction of Sediment Control Ponds in 1987, will provide the Division with the above information. Also, TR-36 covers projected pond construction needs for Trapper Mine through 2003 in the referenced drainages ((See (note), enclosed Maps M51, sheets one and two.)) Thus, TR-36 is based upon the worst case year for each refer- enced drainage. The worst case year does not occur for the Colt Pit area until 1988 for the Coyote drainage, 1989 and 1990 for the East and West Buzzard drainages respectively. PR-1 only addresses 1987 activities. Regardless, pond construction proposed for 1987 will be based on handling the runoff and sediment from the projected worst case year in each drainage. Thus, in the interim, the soon-to-be submitted proposed new pond con- struction technical revision should be considered as an over-design to meet current and projected disturbance for 1987. We are fully aware that after Division review of proposed activities under PR-2 that Trapper may be required to add additional sediment control faciliity structures if designs are insufficient to meet projected 1988 thru 2003 activities.