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~; <br />., <br />TERRA THERMA, INC. <br />III IIIIIIIIIIIII III <br />WATER CONSULTANTS AND ENGINEERS <br />8341 5. Sangre de Cnsto Rd., Su Re 6, L~nleron. CO d07?; <br />November 21, 1985 <br />(30319°3- a9_ ~~e. r- ..~,~ <br />New Castle Energy Corporation N8V z ~ 1985 <br />9137 East Mineral Circle <br />Englewood, Colorado 80112 <br />(1(~f"S~~ ~~Pi1 Ate:.;`:~>i:l!iJi'i <br />Attention: Mr. Clem Parkin C010. D9pi.Of Pi?±_~al Hd3^.~icec, <br />Re: STABILITY OF SPOIL PILES AT PORTALS OF ACCESS DRIVES <br />Dear Clem: <br />As per your request, I have reviewed the stability of the proposed spoil dumps <br />at the portals of the access drives for the New Castle Mine. This letter <br />contains my conclusions and recommendations for the piles. <br />1. Pile foundation conditions <br />The materials upon which the piles are to be dumped are described by Chen and <br />Associates ("Subsurface Study for Dewatering Structure and Thickener <br />• Foundations and Grading Design, New Castle Energy Corporation Mine, East of <br />New Castle, Garfield County, Colorado, dated November 11, 1985). The <br />materials "are predominantly alluvial fan deposits consisting of sandy clays <br />and clayey sands with varying gravel, cobble, and boulder content and clayey <br />to silty sands and gravels with cobbles and boulders." (p. 8). The report <br />notes that no free water was encountered during the investigation drilling, <br />which penetrated to a depth of 71 feet. <br />Based on two shear tests of materials somewhat further to the north than the <br />proposed piles, the strength parameters of the foundation materials for the <br />piles is: <br />Hole •Depth Friction Angle Cohesion <br />No (ft) (degrees) (psf) <br />2 15 35 300 <br />1 5 29 550 <br />These results are typical for the material described above. <br />• <br />