2009-11-02_REVISION - C1991078 (2)

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2.2 Determination of Ground Cover Ground cover at each sample point was determined utilizing the point-intercept methodology as illustrated on Exhibit 1. As indicated in this figure, Cedar Creek utilizes state-of-the-art instrumentation it has pioneered to facilitate much more rapid and accurate collection of data. A transect of 10 meters length was extended in the direction of the next sampling location from the flagged center of each systematically located sample point. At each one-meter interval along the transect, a "laser point bar" was situated parallel to, and approximately 4.5 feet vertically above the ground surface. A set of 10 readings was recorded as to hits on vegetation (by species), litter, rock (>2mm), or bare soil. Hits were determined at each meter interval by activating a battery of 10 low-energy specialized lasers** situated along the bar at 10 centimeter intervals and recording the variable intercepted by each of the vertically projected narrow (0.02 focused beams (see Exhibit 1). In this manner, a total of 100 intercepts per transect were recorded resulting in 1 percent cover per intercept. (Second hits on understory vegetation were not collected owing to the managerial nature of collected data.) All reclaimed area plants as well as reference area plants (including both herbaceous and shrub strata) were subject to sampling. this methodology and instrumentation facilitates the collection of the most unbiased, repeatable, and precise ground cover data possible. 2.3 Sample Adeauacv Determination Sampling of the individual units was restricted to 20 samples for the reclaimed area (10 for the adjacent native area and 5 for each of the 4 segregate reference areas) for cover due to the managerial nature of collected data. However, for informational purposes, sampling adequacy (nmi„) has been calculated for each variable in each sampling unit in accordance with the Colorado guideline (April 18, 1995) formula for sample adequacy when statistical testing is not required, as follows: nmin - (t2S.2) / (0.11)2 Where: n = the number of actual samples collected with a minimum of 5 in each unit; t = the 1-tailed value from the t distribution for 90% confidence with n-1 degrees of freedom; S2 = the variance of the estimate as calculated from the initial samples; x = the mean of the estimate as calculated from the initial samples. ** Lasers utilized for this instrument are state-of-the-art and of specialized design to emit a unique electro-magnetic wavelength visible under full sunlight, a condition previously not possible with portable low-energy lasers. CEDAR CREEK ASSOCIATES, Inc. Page 4 Hamilton Mine - Revegetation Evaluation - 2009