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predictive equations for the reclamation azeas from 2002-2004 was that of a broadly <br />concave mathematical curve originating with a low rate of total cover accumulation and <br />gradually accelerating through increasing levels of precipitation, still gradually accelerating <br />in increase at the highest level of precipitation encountered in the data set. <br />With the addition of data from 2002 forward, high levels of correlation were obtained in <br />2002 and 2003 (RZ values of 0.9867 and 0.9341 respectively), while a significant decrease <br />in the level of correlation occurred with the inclusion of the 2004 data (RZ value of <br />0.4671). <br />3.2.2.2 Total Herbaceous Production <br />Figures AIO through A12 portray the relationship of total herbaceous production in the <br />1995, 1997, and 1998 Reclamation Areas and cumulative September-July precipitation for <br />the years subsequent to the 2002 investigation. Each subsequent plot adds one yeaz of <br />production and precipitation data and portrays the accompanying best-fit curve with <br />corresponding equation and correlation coefficient. <br />Total herbaceous production predictive equations at the reclamation areas were more <br />varied in character than was observed in the 2002 investigation, or for any other <br />parameter. In the 2002 data set (Figure A10), a third order polynomial equation provided <br />a high level of correlation (RZ value of 0.8949), yet the significant inflexion in the middle <br />range of the precipitation range was not explained in the field or by theory. The second <br />• highest level of correlation (RZ= 0.7562) was provided by a logarithmic exponential <br />equation of a broadly concave nature. <br />In 2003, the best-fit predictive equation was an exponential equation of a broadly concave, <br />nearly linear nature (Figure All). The RZ value of 0.7238 revealed a lower correlation <br />level than that from the 2002 data set. <br />The addition of 2004 data (Figure A12) showed a similar condition as the 2002 data set. <br />A third order polynomial equation provided the highest level of correlation for the year <br />(RZ value 0.5364), yet the significant inflexion in the middle range of the precipitation <br />range was not explained in the field or by theory. The second highest level of correlation <br />(R2= 0.4716) was provided by a second order polynomial equation of a broadly concave <br />nature. <br />4.0 DISCUSSION <br />4.1 Osgood Sand Reference Area <br />4.1.1 Total Vegetation Cover <br />Plotting the 2002-2004 total vegetation cover data from the Osgood Sand Reference Area <br />• did not reveal any significant changes to the overall shape of the plotted best-fit predixive <br />Coors Energy Comparry Keenesburg Mine Page 7 <br />2005 Addendum to Revision of Revegetation Success Criteria <br />