2011-03-15_REVISION - M1981185 - Laserfiche WebLink

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Memo to Wally Erickson 2 August 2, 2009 Second Review of Access Road Construction File No. M-2006-069 states that Wildcat Mining must provide a plan to include laying back and vegetating the cuts in sand and gravel with cobble along both sides of this stretch of the road. No such plan has been provided. Turf reinforcement mats would be ideal for these cut slopes once they are laid back. The "As-Build Report" states that the road construction crew was directed to place fill in eight inch lifts and compact using a John Deere 650, which is a small tracked bull dozer, and a John Deere 316 back hoe. Tracked vehicles are not the preferred type of equipment for compaction of rock fill; rubber tired equipment is better, and vibratory drum rollers are ideal. However, the DRMS concurs that sufficient compaction would result by tracking with the Deere 650 with lifts as thin as the eight inch specified. The DRMS June 5, 2009 memo required submittal of "a report from the geotechnical engineer who was on-site during construction as required by the Department of the Army" and further required that the "geotechnical report must describe all aspects of the construction of the road fill, and include photographs and the results of geotechnical tests conducted" During the June 23, 2009 telephone meeting, Paul Martin discussed the following: 1. He acted as the on-site geotechnical engineer-during construction. He was on-site observing the construction only a fraction of the time that construction was occurring. 2. There were no geotechnical tests conducted. Mr. Martin stated that since the fill installed is a rock fill, compaction -tests such as those typically used for soil fills were not applicable. It is correct that there are no direct geotechnical tests available to measure the degree of compaction of a rock fill. Wildcat Mining must state definitively when and for how long Mr. Martin was on-site and relate that to the days and hours the construction crew was building the, road. Wildcat Mining must provide any photographs of road construction that are available. Wildcat Mining must provide a definitive statement as to whether or not Mr. Martin made sufficient observations and possesses sufficient information about construction activities to issue an engineer's certification that the fill was placed and compacted in eight inch. lifts, and if such a certification can be made, provide the written certification. During the May 15, 2009 site inspection, DRMS observed that the fill slopes are extremely steep; native timber has been used in an effort to retain the fill. Steel cable has been installed among and throughout the timber post and beam installations. In places, the timbers have been notched, interlaced, and driven through with steel spikes. On the fill slope above the pond, several of the formerly upright posts are listing in excess of 20 degrees from vertical, and the notched beams are detached and have moved downslope. All of the steel cables that were checked were loose. The drawings of the road fill prepared by Sakura Engineering show timbers completely embedded into the fill and cabled to the exterior retaining timbers. During the inspection, DRMS discussed the construction of the road with Tom Baca, who was on the construction crew; he stated that the one prominent post in the fill above the pond that extends about 14 feet above surface and is severely listing, extends an equal 14 feet below grade. When questioned, Mr. Baca was unclear about the number, location, and cabling of completely buried timber posts embedded in the fill. The inspection observations and review of the drawings lead to the following questions for Wildcat Mining that have not been answered in the "As-Build Report" or elsewhere in the permit application documents: 1. Were the embedded posts installed as shown on the drawings; can the on-site engineer provide a written certification?.