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ASSESSMENT CONFERENCE SUMMARY NOV C-92-017 NOV C-92-017 was issued by Cathy Begej of the Division on August 3, 1992, based on an inspection she made of the Harrison Western Corp. (HW) liability area at the G.E.C. Mine on July 28, 1992. The NOV was issued for "failure to pass drainage from a disturbed area through a sediment pond". Ms. Begej opened discussion of the NOV by reviewing the April, 1992 compliance agreement entered into between HW and the Board. The compliance agreement was written for the purpose of clarifying HW's responsibilities as guarantor performing reclamation on a small portion of the GEC west Pit. One condition of the compliance agreement required HW to construct a diversion to direct undisturbed drainage around the pond, in an effort to restrict sediment pond inflow to runoff from the reclaimed West Pit area. The dimensions of the diversion were to be agreed upon by HW and the Division. The Division approved a design and the ditch construction was completed in late June. Ms. Hegej explained that on her July 28th inspection, it was evident that a significant rainfall/runoff event had occurred a few days earlier. Runoff from the reclaimed swale/drainage which directs West Pit runoff into the sediment pond had apparently breached the adjacent diversion ditch berm, allowing disturbed area runoff to flow offsite, bypassing the sediment pond. A rock check dam constructed in the reclaimed drainage apparently contributed to this problem, as the breach occurred adjacent to the check dam. Mr. Williams expressed his opinion that the breach might have been caused by runoff water coming down the diversion ditch from the undisturbed drainage above rather than from runoff coming down the reclaimed drainage. Ms. Begej based her determination on deposition of sediment and debris into the diversion ditch at the breach location and a lack of debris or other evidence indicating that runoff had reached the diversion from the undisturbed drainage above. Mr. Williams indicated that he had not closely investigated the undisturbed drainage for evidence of flow into the diversion. Mr. Williams agreed that the check dam, as it was constructed was not a prudent design, because the crest of the check dam was approximately the same elevation as the crest of the adjacent diversion ditch bean. The location and specific design of the check dam had not been specified in the approved drainage plan, but the Division had recommended several weeks earlier that the diversion ditch berm be built up in that location. Mr. Williams indicated that work on the berm with heavy equipment had not been performed because wet conditions had precluded access. Ms. Begej did not concur and referenced precipitation records from the adjacent Southfield Mine which indicated the first two weeks of July had been dry, with a period of frequent precipitation beginning July 14. My conclusion is that a violation did occur. Based on the evidence presented it appears that the drainage system was compromised and disturbed area drainage from the west Pit reclamation area entered the diversion ditch and bypassed the sediment pond. M:\wp51\nov017.dtm