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<br />/~~1~7 ACZ Inc. sss <br />[i~~lfl I_'~Jf/~/ Engineering end Envlronmentel Services <br />1475 Pine Grove Road, Suite 109 <br />P.O. Box 774018 <br />Steamboat Springs, Colorado 804%7 <br />303-879-6260 , _ .-, ^ I J ~ f-` <br />September 3, 1993 gip 1 p 1993 <br />Mr. Kent A. Gorham, Reclamation Specialist t)rv!aCn u~ :.Gl:e~d~b a iaeC!ogy <br />Division of Minerals and Geology <br />1313 Sherman Street, Room 215 <br />Denver, CO 80203 <br />~l t/ d rc>. <br />Re: The Rockcastle Company -Grassy Gap Mine (C-81-039): Results of Final Surface <br />Water and NPDES Sampling <br />Dear Mr. Gorham: <br />On behalf of The Rockcastle Company (ROCKCASTLE), ACZ Inc. (ACZ) has conduced <br />surface water sampling and laboratory analyses at the Grassy Gap Mine located south of <br />Hayden, Colorado in Routt County. The purpose of the sampling was to provide final <br />measurements and documentation of the water quality at specified locations coincident with <br />final reclamation activities and anticipated bond release. A description of the sampling plan <br />and laboratory results follows. <br />SAMPLING PLAN <br />On August 4, 1993, ACZ conducted sampling to provide final documentation of existing <br />surface water quality at key locations at the mine site. The sampling was not designed to <br />meet all guidelines in the Mining and Reclamation Permit or the Colorado Wastewater <br />Discharge Permi[ (NPDES) for mine. The ]options sampled included the most down-stream <br />surface water monitoring point (SW-4), the pooled water in the former sedimentation Pond <br />5/6 (now a stock pond) and the three (3) springs with the greatest flow rates. Field <br />measurements were made at each loption, with sampling locations shown on Map 1. <br />Laboratory [esting parameters were identipl to those required in each permit. The tests <br />included a "full suite" of analyses, as described in the NPDES permit. The springs were <br />only analyzed for Total Dissolved Solids ('I'DS). The recent water quality analyses as well <br />as those from 1992 are included for your review. Laboratory results are attached and <br />previous laboratory results were submitted to your department in the Annual Hydrology <br />Reports for 1991 and 1992. <br />MONITORING RESULTS <br />ACZ personnel conducted an inspection, field measurements, and sampling of the stock <br />pond. Minor sub-flow was noted through the rocked spillway. Pond 4 was reclaimed in <br />1992 and no discharge was observed from this area. The laboratory results and field <br />measurements for the stock pond and the former sedimentation Pond 5/6 (Discharge Point <br />005) in 1992 and 1993 are presented in Table 1, Discharge Point 005 Monitoring. The <br />results were consistent with previous findings. <br />Field easurements, sampling, and laboratory analyses were conducted at surface water <br />locatio SW-4, lopted at the culvert outlet beneath the Pit 4 access road. This represents <br />the most wn-scream surface water quality measurement location. Additional surface water <br />,- <br />