The evidence against you is fairly clear mate:
Mmmcheezburger
2011-10-14 18:36:00 > 2011-10-14 18:56:51 (20mins 51secs)
38 diamond ore breaks
0 Gold ore breaks
4 iron ore breaks
Total block breaks 299 (that's over 1 in 10 blocks mined was a diamond ore..)
Here he's done a 90 degree turn directly to diamond ore (which was behind several layers of stone)
7076514 2011-10-14 18:45:13 mmmcheezburger Block Break Northern_Kingdoms 580,12,-563 Diamond Ore
7076629 2011-10-14 18:45:37 mmmcheezburger Block Break Northern_Kingdoms 579,8,-572 Stone
7076633 2011-10-14 18:45:38 mmmcheezburger Block Break Northern_Kingdoms 579,7,-572 Stone
7076646 2011-10-14 18:45:40 mmmcheezburger Block Break Northern_Kingdoms 578,8,-572 Stone
7076650 2011-10-14 18:45:41 mmmcheezburger Block Break Northern_Kingdoms 578,7,-572 Stone
7076654 2011-10-14 18:45:42 mmmcheezburger Block Break Northern_Kingdoms 577,7,-572 Stone
7076663 2011-10-14 18:45:43 mmmcheezburger Block Break Northern_Kingdoms 577,8,-572 Stone
7076668 2011-10-14 18:45:43 mmmcheezburger Block Break Northern_Kingdoms 576,7,-572 Stone
7076680 2011-10-14 18:45:45 mmmcheezburger Block Break Northern_Kingdoms 576,8,-572 Stone
7076703 2011-10-14 18:45:49 mmmcheezburger Block Break Northern_Kingdoms 575,8,-572 Stone
7076714 2011-10-14 18:45:49 mmmcheezburger Block Break Northern_Kingdoms 574,8,-572 Stone
7076717 2011-10-14 18:45:50 mmmcheezburger Block Break Northern_Kingdoms 575,7,-572 Stone
7076721 2011-10-14 18:45:51 mmmcheezburger Block Break Northern_Kingdoms 574,7,-572 Stone
7076735 2011-10-14 18:45:53 mmmcheezburger Block Break Northern_Kingdoms 573,7,-572 Diamond Ore
Again not long after having already cleared yet another vein of diamond, from one vein to another with 1 block wide, 2 block high tunnels
7076824 2011-10-14 18:46:08 mmmcheezburger Block Break Northern_Kingdoms 572,9,-571 Diamond Ore
7077166 2011-10-14 18:47:24 mmmcheezburger Block Break Northern_Kingdoms 572,8,-591 Stone
7077169 2011-10-14 18:47:24 mmmcheezburger Block Break Northern_Kingdoms 572,7,-591 Stone
7077175 2011-10-14 18:47:25 mmmcheezburger Block Break Northern_Kingdoms 571,7,-591 Stone
7077182 2011-10-14 18:47:26 mmmcheezburger Block Break Northern_Kingdoms 571,8,-591 Stone
7077186 2011-10-14 18:47:26 mmmcheezburger Block Break Northern_Kingdoms 570,8,-591 Stone
7077191 2011-10-14 18:47:27 mmmcheezburger Block Break Northern_Kingdoms 570,7,-591 Stone
7077200 2011-10-14 18:47:28 mmmcheezburger Block Break Northern_Kingdoms 569,8,-591 Stone
7077208 2011-10-14 18:47:29 mmmcheezburger Block Break Northern_Kingdoms 569,7,-591 Stone
7077213 2011-10-14 18:47:29 mmmcheezburger Block Break Northern_Kingdoms 568,7,-591 Stone
7077217 2011-10-14 18:47:30 mmmcheezburger Block Break Northern_Kingdoms 567,7,-591 Stone
7077223 2011-10-14 18:47:31 mmmcheezburger Block Break Northern_Kingdoms 568,8,-591 Stone
7077227 2011-10-14 18:47:31 mmmcheezburger Block Break Northern_Kingdoms 567,8,-591 Stone
7077232 2011-10-14 18:47:32 mmmcheezburger Block Break Northern_Kingdoms 566,8,-591 Stone
7077237 2011-10-14 18:47:33 mmmcheezburger Block Break Northern_Kingdoms 566,7,-591 Stone
7077240 2011-10-14 18:47:33 mmmcheezburger Block Break Northern_Kingdoms 565,7,-591 Stone
7077246 2011-10-14 18:47:34 mmmcheezburger Block Break Northern_Kingdoms 564,7,-591 Stone
7077250 2011-10-14 18:47:35 mmmcheezburger Block Break Northern_Kingdoms 565,8,-591 Stone
7077277 2011-10-14 18:47:42 mmmcheezburger Block Break Northern_Kingdoms 565,7,-592 Diamond Ore
7077279 2011-10-14 18:47:42 mmmcheezburger Block Break Northern_Kingdoms 565,6,-592 Stone
7077293 2011-10-14 18:47:46 mmmcheezburger Block Break Northern_Kingdoms 565,6,-591 Iron Ore
7077304 2011-10-14 18:47:48 mmmcheezburger Block Break Northern_Kingdoms 564,7,-592 Diamond Ore
7077322 2011-10-14 18:47:51 mmmcheezburger Block Break Northern_Kingdoms 565,7,-593 Diamond Ore
7077328 2011-10-14 18:47:52 mmmcheezburger Block Break Northern_Kingdoms 564,7,-593 Diamond Ore
This happens regularly in your logs - it's not just these two instances, you move from one vein to another ignoring everything else. When I visited the locations you had cleared all diamonds in the area with tunnels directly to them, clearing out the ores and setting off to another vein nearby. I can't explain this as it's not how normal people mine and it's not "just lucky" either, unless lucky includes the ability to see through several layers of rock.