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RECEIVED <br /> June 18, 1984 JUN <br /> J iGc, 1 1 b 1;;04 <br /> MINED LAW PWIS10N ` 'cro• 1116,37 <br /> Colo. Dept. of ... es <br /> Mr. Steven Nottingham <br /> Nottingham Sand 6 Gravel <br /> P. 0. Box 935 <br /> Avon, CO. 81620 <br /> RE: Preliminary field investigation concerning the potential hazard <br /> of excavating alongside the railroad R.O.W. in your Eagle Gravel <br /> Pit. <br /> Dear Mr. Nottingham: <br /> After having field measured and studied the situation of your excavation <br /> alongside the railroad tracks in your gravel pit in Eagle, and after having <br /> platted the data (see attached Exhibit "A") , and having made use of some <br /> references, I have found the following: <br /> 1 . My first conclusion is that there is no reason whatsoever to be <br /> concerned about the stability and/or performance of the railroad tracks <br /> as they exist today in relationship to your general pit operation. <br /> 2. As per standard design practice the pressure bulb that would exist <br /> under any load traveling along the tracks only extends a distance equal <br /> to 1.4 times one—half the width of the surface pressure width. <br /> Consequently, if a 100 ton train is loading a 12' wide bed, the maximum <br /> distance from the edge of the loaded area at which one can find any <br /> measurable stresses (5% and less of surface stresses) is 8.4' from the <br /> edge of the load. <br /> References : Foundation Engineering Handbook by Winterkorn and Fang <br /> Foundation Engineering by Peck, Henson <br /> Soil Mechanics by Lambe and Whitman <br /> 3. The only other major factor that could possibly affect the situation <br /> encountered in the field is that of slope stability. However, unless a <br /> detailed analysis is run, factual numbers would be hard to be arrived <br /> at. It is my opinion, based on reading and having full understanding <br /> of the above references, that slope stability can only become a problem <br /> if an overload is placed too close to the edge of the cut . The type of <br /> soils encountered in the field are capable of maintaining very steep <br /> stable slopes , better than 1:1; therefore, after observing that on the <br /> average the finished slopes are better than 2 :1, I definitely would <br /> tend to drift away from the thought of potential slope instability <br /> problems. <br />