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To: Jim Stover; J. E. Stover & Associates, Inc. <br />From: CI&DARCMKAMOCUTTA Inc. <br />Date: November 16, 2016 <br />Subject: Small Area Sampling <br />With regard to correctly sampling vegetation variables within a re -disturbed reclaimed area, there are <br />certain practical and statistical limitations that must be considered. Typically, an area of re -disturbance is <br />included with remaining reclaimed acreage for eventual measurement, comparison, and final bond <br />relinquishment. However, when an area of re -disturbance occurs near the end of the reclamation liability <br />period combination with other acreage is not possible. In this circumstance, an alternate procedure <br />becomes necessary. <br />This circumstance raises a potential issue: that if re -disturbance involves very small acreage, there are <br />both practical as well as statistical limitations to success evaluations. From the practical side of things, <br />exceptions can be found in the guidance of several western states, often involving "SAES" or Small Area <br />Exclusions (or Exceptions). Typically, these SAES are anomalies that are too small to have any adverse <br />effect on the surrounding area unless they exhibit unique circumstances such as acid generation. Absent <br />such unique circumstances, most regulatory authorities simply consider such SAES to be inconsequential <br />and it is assumed that the natural environment is adequate to reclaim re -disturbances in a timely <br />manner. In Cedar Creek's experience, such SAEs typically range between 0.05 and 0.5 acres, but <br />sometimes larger. Similarly, in Colorado's Vegetation Guidelines (1988) there is discussion / guidance for <br />"major and minor communities". In effect, no quantitative sampling is required of "minor" communities <br />(less than 5% of a permit area or 10 acres, whichever is less) unless those communities are <br />disproportionately or exceptionally high value (such as a wetland). Again, absent unique circumstances, <br />any re -disturbance less than 10 acres or 5% of the permit area could or should be considered <br />inconsequential under this guidance. From a practical viewpoint, 10 acres is a unit of land sufficiently <br />sizeable to facilitate quantitative vegetation sampling. This then leads to the question: how small is too <br />small to allow unfettered sampling from a statistical perspective? <br />Depending on the variable being measured and the metric being utilized, there typically is a minimum <br />size for a unit of land that may be correctly evaluated statistically. One notable exception is the variable <br />of ground cover as measured by point -intercept techniques; because "points" have no effective area. <br />However, both the variables of production (biomass) and woody plant density are limited to sampling <br />techniques that involve areal measurements (pounds of biomass or numbers of plants per unit area). <br />This "unit area" concept invokes one of the principal assumptions of statistical theory, that samples must <br />be independent and equally probable. Adherence to this assumption using sampling techniques involving <br />TR -69 A14-16-1 12/16 <br />