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March 21, 2014 <br />Page 35 <br />Table 4. Summary of Physical Property Test Results, <br />GT -01 Holes (AAI 2003) <br />Strata <br />ac <br />Seam <br />ac <br />E, 106 <br />psi ( %) <br />(psi) <br />(psi) <br />G78 Roof <br />6,508 <br />1.46 <br />G78 Coal <br />1,672 <br />0.33 <br />G78 Floor <br />5,892 <br />1.32 <br />Table 5. Summary of Physical Property Test Results, South Taylor <br />2006 and 2007 Holes (Shannon and Wilson 2008) <br />Strata <br />ac <br />at S <br />50 -75 <br />(psi) <br />psi ( %) <br />Sandstone <br />2,750 <br />175 - <br />Siltstone <br />5,145 <br />283 - <br />Mudstone <br />5,243 <br />263 - <br />Carbonaceous mudstone <br />4,690 <br />140 - <br />E Seam <br />2,610 <br />- - <br />F Seam <br />2,600 <br />- - <br />G78 Floor <br />- <br />- 83 <br />Table 6. Slake Durability Classification <br />Second Cycle Slake Durability (% = Classification) <br />0-25 <br />Very Low <br />25 -50 <br />Low <br />50 -75 <br />Medium <br />75 -90 <br />High <br />90 -95 <br />Very High <br />95 -100 <br />Extremely High <br />According to this classification criterion, the immediate floor rocks have medium to high <br />durability and should provide good pit floor and highwall miner floor conditions, as has <br />generally been the experience at Colowyo. <br />Based on average compressive strength values given in Tables 3 and 5, and on RQD <br />values from available South Taylor core logs, it appears that the mudstone parting between the <br />G7 and G8 seams, and the D2 and E seams in South Taylor are competent, and that pillar designs <br />for the combined G78 and D2 /E seams can be based on the coal strength, without special <br />consideration of the parting. <br />Agapito Associates, Inc. <br />