Thanks, good to know this.
Always a problem how to handle core loss in weathered zones (especially, as generally more obvious in fresh rock most of the time).
Agree, within reason, there has to be a way to handle these, not uncommon, issues to JORC standard.
When I was adding the assays to my database I did notice the core loss column. First time presented, I think, and had to add a column.
Took a look at the data and made a subset from >=2.7m of loss.
Treat the results in these zones as a best guess. They will be high with some degree of uncertainty even with triple tube drilling - PQ/HQ/NQ?? Most likely HQ to fresh rock IMO but that is a guess.
| hole | from | to | interval | Nb2O5 | phosphate | m% | core loss |
|---|
| 1 | LUDD23007 | 66 | 90 | 24 | 3.22 | 2.8 | 77.3 | 7.3 |
|---|
| 2 | LUDD23007 | 66 | 101 | 35 | 2.22 | 9.8 | 77.7 | 8.5 |
|---|
| 3 | LUDD23007 | 105 | 169 | 64 | 2.09 | 10.8 | 133.8 | 10.4 |
|---|
| 4 | LUDD23007 | 126.6 | 166.7 | 40.1 | 3.19 | 3.3 | 127.9 | 7.7 |
|---|
| 5 | LUDD23008 | 56 | 74.9 | 18.9 | 0.92 | 10 | 17.4 | 5.7 |
|---|
| 6 | LUDD23009 | 43 | 62.3 | 19.3 | 1.3 | 3.6 | 25.1 | 8.4 |
|---|
| 7 | LUDD23010 | 79.7 | 120.3 | 40.6 | 0.75 | 23.1 | 30.5 | 5.2 |
|---|
| 8 | LUDD23014 | 93.6 | 116.2 | 22.6 | 3.77 | 10.9 | 85.2 | 11.0 |
|---|
| 9 | LUDD23014 | 93.6 | 123.4 | 29.8 | 3.07 | 9.8 | 91.5 | 14.5 |
|---|
| 10 | LUDD23015 | 60.7 | 90.7 | 30 | 1.05 | 12.1 | 31.5 | 6.1 |
|---|
| 11 | LUDD23015 | 97.4 | 199 | 101.7 | 0.46 | 4.2 | 46.8 | 12.0 |
|---|
| 12 | LUDD23017 | 83 | 128 | 45 | 1.18 | 4.6 | 53.1 | 2.7 |
|---|
| 13 | LUDD23017 | 145 | 170 | 25 | 0.46 | 12.1 | 11.5 | 3.6 |
|---|
| 14 | LUDD23021 | 46.5 | 61 | 14.5 | 2.51 | 11.4 | 36.4 | 5.0 |
|---|
| 15 | LUDD23021 | 46.5 | 121 | 74.5 | 0.72 | 10.7 | 53.6 | 5.2 |
|---|
| 16 | LUDD23026 | 55.4 | 132.4 | 77 | 0.67 | 6.8 | 51.6 | 12.6 |
|---|
| 17 | LUDD23027 | 87.8 | 113 | 25.3 | 1.55 | 10.8 | 39.2 | 6.7 |
|---|
| 18 | LUDD23027 | 87.8 | 136.5 | 48.8 | 1.16 | 8.8 | 56.6 | 14.8 |
|---|
| 19 | LUDD23027 | 126.8 | 134 | 7.2 | 1.28 | 4.4 | 9.2 | 4.4 |
|---|
| 20 | LUDD23032 | 90 | 149 | 59 | 1.4 | 11.1 | 82.6 | 9.5 |
|---|
| 21 | LUDD23033 | 112 | 131.9 | 19.9 | 2.15 | 6.3 | 42.8 | 13.5 |
|---|
| 22 | LUDD23035 | 53.5 | 77.1 | 23.6 | 10.3 | 11.2 | 243.1 | 6.1 |
|---|
| 23 | LUDD23035 | 53.5 | 119 | 65.5 | 3.33 | 6.4 | 218.1 | 6.2 |
|---|
| 24 | LURCD23042 | 119 | 160 | 41 | 0.64 | 27.4 | 26.2 | 4.7 |
|---|
Intersections beginning >100m down hole are likely to be approaching fresh rock. Still getting core loss at these depths! Water table/influx? near contact weathered/fresh?
Ah the joys of drilling in challenging environments. Leaving it to a younger generation...
Personal experience of massive core loss and a lot of rubble. How to assign intervals? Was it even worth it for this zone? Au was target rather than Nb/REE which did make decisions less critical.
Palaeochannel country in this image vs a more consistent(?) weathered profile above fresh carbonatite.
Hope the WA1 core didn't resemble this too much.
Sonic drilling test will be interesting as it can do well in unconsolidated/soft material. Never dealt with it but did see good recoveries from a tailings facility once.
(20min delay)