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NORTH THOMPSON CREEK SITE INFORMATION <br />Facts: <br />Precipitation: 2211 annually, 3511 at higher elevation <br />Mine site is in recharge area with peak surface flow in May <br />and June, and low flow in September through February. <br />Rock strata dip 27 to 35 degrees to the west. <br />3 sandstone units: Rollins, source of No 1 portal mine flow. <br />Middle and Upper <br />History <br />The site was originally mined from 1911 to 1964. Snowmass Coal <br />company mined the North Thompson Creek area mine from 1971 to June of <br />1984 when mine inflow of water became a severe problem. Flooding of the <br />mine began in August of 1986 in Mine #I and Mine #3. An entire long <br />wall operation was left underground. <br />Site reclamation began in 1986 with the refuse area and continued <br />until 1987. The only topsoil salvaged on the site came from the refuse <br />area and construction later of the long pond and pond P-9. <br />Phase I bond release was in March of 1988. In May of 1988, the <br />portal seal in Mine #1 blew and the water began leaking into the creek. <br />A treatment system for the water was begun in July of 1988 and has <br />evolved over time into the current system in place. <br />The Rollins sandstone is faulted and fractured to the south of the <br />creek, allowing water to percolate through the mine workings and seep <br />through the current seal at Portal Mine #1. The treatment system <br />receives 30 plus gpm. from this effect. It is believed that maybe the <br />high iron content (100 ppm) is due in part to the underground <br />connection to Mine #2, located upslope and directly across from Mine <br />Portal #1. The Abandoned Mine Land office has reclaimed Mine J2, which <br />has the same fingerprint of water discharge. Some old workings did <br />intercept the portal #2 passageways to the north. Mine #2 predates <br />SMCRA and is therefore not the inspection responsibility of OMLR. It is <br />currently batgrated with a wetlands mitigation fenced area and <br />connecting ditch to the creek for any mine discharge. <br />Phase I bond release occurred in March 1988, following an OSM <br />inspection and landowner approval. Seep noted near reclaimed portal <br />area in April of same year by inspector. Portal reexcavated in May and <br />two areas of discharge discovered; one, the portal #1 seal was leaking, <br />and two, the air shaft was spilling iron heavy waters in excess of 30 <br />gpm. The re-excavated material is next to the topsoil pile, with no <br />sign. The topsoil pile is from the re-excavated portal, removed when <br />the leak was found. This re-excavated area is the only SAE on the site. <br />Treatment System <br />The treatment system has been a trial and error process in three <br />phases: First, a french drain system was constructed with a bentonite <br />bench between the drain and creek. Remnants of the <br />