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I-4 <br />f <br />• <br />Very soft rock -material crumbles under firm 5 <br />blows with a sharp end of a <br />geological pick and can be peeled <br />off with a knife. It is too hard <br />to cut a triaxial sample by hand <br />Soft rock - can just be scraped and peeled 6 <br />with a knife; indentations 1/16 <br />in. to 1/8 in. show in the <br />specimen with firm blows of the <br />pick point <br />Hard rock - cannot be scraped or peeled with 7 <br />a knife; hand-held specimen can be <br />broken with a hammer end of a geo- <br />logical pick with a single firm <br />blow <br />Very hard rock -hand-held specimen breaks with 8 <br />hammer end of pick under more <br />than one blow <br />CJ <br />l J <br />Very, very hard - specimen requires many blows with 9 <br />rock geological pick to break through <br />intact material <br />ALPHA Ca) ANGLE <br />The n angle is the minimum angle of intersection between <br />the structure or discontinuity and the core (or drill hole) <br />axis. The magnitude of a varies from 0° to 90°. <br />RaD <br />The RQD of core means the Rock Quality Designation of that <br />core interval in question. RQD is effectively a modified core <br />recovery. To compute the RQD for any core interval, the number <br />of pieces of core 4 inches or more in length are cumulatively <br />measured and divided by the length of the actual core interval <br />drilled. In other words, RQD is computed in the same procedure <br />as the standard core recovery, except all pieces 4 inches or <br />less are assumed to be lost. RQD magnitudes accordingly range <br />from OZ to 1001. <br />SEEGMILLER INTERNATIONAL <br />