Hello,
After
running ordinary kriging estimations using Vulcan mine planning software it
was noticed there were some unusual estimated grades. I was hoping that
someone can confirm that I on the right path + not heading up the yellow brick
road to Oz.
The
estimated value reported/calculated by Vulcan for one block was 80.77. I
thought this unusual as the grade of the 16 samples selected for the
estimation range from 51.2 to 65.9 (mean 59.6). I calculated
the estimated grade by summing the products of sample grade and sample
weight (given by the software) and got a value of 60.13 which seems far
more reasonable.
Maptek
the software vendor's response was to suggest that negative weights were
responsible for the high estimation.
Details of the samples are below.
Have
I overlooked something in my calculation or is there some
other explanation for the result?
Regards
David
Reid
| Number | X | Y | Z | Grade | Distance | weight | weight * grade |
| 1 | 51325.6 | 19954.3 | 205.28 | 64 | 8.755 | 0.316811 | 20.27589 |
| 2 | 51325.6 | 19954.3 | 206.8 | 64 | 12.751 | 0.047555 | 3.043512 |
| 3 | 51310 | 19953.7 | 206.95 | 65.9 | 15.699 | 0.097072 | 6.397071 |
| 4 | 51308.2 | 19968.6 | 206.58 | 51.2 | 19.183 | 0.078537 | 4.021086 |
| 5 | 51309.4 | 19970.1 | 206.67 | 63.9 | 19.557 | 0.05828 | 3.724066 |
| 6 | 51325.3 | 19939 | 205.08 | 58.2 | 19.948 | 0.08432 | 4.907436 |
| 7 | 51310 | 19939.3 | 204.78 | 55.1 | 21.197 | 0.117351 | 6.466049 |
| 8 | 51325.3 | 19977.5 | 204.98 | 56.7 | 21.267 | 0.182511 | 10.34838 |
| 9 | 51310.3 | 19938.7 | 204.88 | 60 | 21.646 | 0.085906 | 5.154343 |
| 10 | 51325.3 | 19939 | 206.6 | 58.2 | 21.843 | -0.03607 | -2.09928 |
| 11 | 51310 | 19939.3 | 206.3 | 55.405 | 22.767 | -0.00408 | -0.22581 |
| 12 | 51325.3 | 19977.5 | 206.5 | 56.7 | 22.98 | 0.028131 | 1.59505 |
| 13 | 51310.3 | 19938.7 | 206.4 | 60 | 23.259 | -0.02124 | -1.27434 |
| 14 | 51309.4 | 19970.1 | 208.9 | 62.3 | 24.395 | -0.0517 | -3.22108 |
| 15 | 51340.2 | 19939 | 205.48 | 61 | 28.172 | 0.040817 | 2.489816 |
| 16 | 51340.2 | 19939 | 207 | 61 | 29.772 | -0.0242 | -1.4764 |
| TOTAL | 1 | 60.12579 | |||||
| Ave | 59.60031 | block estimate | 80.77 |
David Reid
| This message and any attached files may contain information that is confidential and/or subject of legal privilege intended only for use by the intended recipient. If you are not the intended recipient or the person responsible for delivering the message to the intended recipient, be advised that you have received this message in error and that any dissemination, copying or use of this message or attachment is strictly forbidden, as is the disclosure of the information therein. If you have received this message in error please notify the sender immediately and delete the message. |
* By using the ai-geostats mailing list you agree to follow its rules ( see http://www.ai-geostats.org/help_ai-geostats.htm )
* To unsubscribe to ai-geostats, send the following in the subject or in the body (plain text format) of an email message to [EMAIL PROTECTED] Signoff ai-geostats
