David,
I assume you've checked for the "little things" that may be silly mistakes, such as comparing the same blocks; or making sure that the estimation parameter files are reading the intended variables.
If all the above checks, then it's possible that there is "bug", and that can be in different forms; for instance, incompatability between parameters and files setup in a version, and trying to use them in a newer version (are you trying out V6.0?).
Then again, it could be a true bug, an error in the programming; however, I think this is less likely if you're using the OK program implemented from GSLIB within Vulcan; it has been thoroughly checked and debugged for a number of years (and versions, since 3.5 at least).
Clearly, it's not the negative weights...
Good luck!
Cheers,
Mario
PD: It looks to me like you're dealing with Fe ore; hematite? If you truly happen to have a 80.X value in a block, let me know! I'll fly out there (to WA?) to witness the miracle...
"Reid, David W" <[EMAIL PROTECTED]> wrote:
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?RegardsDavid 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
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