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Mid-Continent Resources, Inc. <br /> PRODUCERS OF THE FAMOUS COAL BASIN COKING COAL <br /> AIID-CO\TINENT RESOURCES,INC. 201 Centennial Street <br /> 625 PL AINFIELD ROAD-SUITE 220 Suite 406 Telephone: <br /> WILLOWBROOK,ILLINOIS 60521 Glenwood Springs, Colorado 81601 (303)945-4958 <br /> June 14, 1989 <br /> James C. Stevens <br /> Senior Reclamation Specialist <br /> Mined Land Reclamation Division <br /> 215 Centennial Bldg. <br /> 1313 Sherman St. <br /> Denver, CO 80203-2273 <br /> Dear Mr. Stevens: <br /> RE: Request for Minor Revision. Use of Aluminum Sulfate at #016. <br /> Mid-Continent requests a Minor Revision to Permit #C-810017 to allow for the use of <br /> aluminum sulfate (alum) to treat mine water discharge for settling purposes at the <br /> tunnel ponds of outfall #016. This treatment method would be used when it is <br /> determined that a settling agent is needed for compliance with effluent limitation <br /> requirements. <br /> Alum is a popular coagulant which has a common usage, including use in many <br /> drinking water systems. Attached is a material safety data sheet for aluminum sulfate. <br /> Mid-Continent purchases alum from Van Waters and Roger of Denver. <br /> The treatment method to involve placement of dry, powdered alum into the mine <br /> discharge pipe at the rock tunnel portal. The alum will be allowed to mix for <br /> approximately 10 minutes as the water flows from the portal down to the rock tunnel <br /> ponds. It is anticipated that the mine water discharge flow treated with alum will range <br /> from 300 to 1500 gpm. <br /> The application rate has not yet been determined. However, past experience has shown <br /> that an application rate of 10 to 50 ppm is usually adequate. Mid-Continent proposes, <br /> with your approval, to start testing alum at 5 ppm, and to increase or decrease the <br /> dosage as needed. <br /> The three existing rock tunnel ponds have a capacity of 10.5 acre-feet. When the fourth <br /> pond is built this summer, the total pond capacity will be 16.3 acre feet. The theoretical <br /> detention time of the three existing ponds, assuming a mine water flow of 1500 gpm <br /> and a 10 yr./24 hour flow of 3.65 acre-feet is 38 hours. There will not be any sort of <br /> aeration or filtration facility associated with this system. <br />