Targeting Workflow Report

Workflow Study: O_Block_targeting
Date: Fri Nov 19 13:12:53 2010



The Targeting Workflow is designed to guide the user through a step-by-step process of combining 3D datasets by different processes to obtain a comprehensive exploration interpretation. The result of the combination is an additional quantitative layer of interpretation that is tied with a multi-disciplinary approach to targeting.

The different combination methods can be based on either subjective empirical models or probabilistic models, referred to as knowledge-driven and data-driven approaches, respectively. Knowledge-driven approaches are based on the experience of domain experts and include processes such as Boolean Logic, Index Overlay, Multi-Class Index Overlay, Dempster-Shafer Belief Theory, and Fuzzy Logic. Data-driven approaches require that known occurrences of what we are looking for exist in the earth model, such as a set of deposits, and include the Prospector Model, Weights-of-Evidence, Weighted Logistic Regression, Likelihood Ratio, and Neural Networks, among others. In addition, hybrid models using combinations of two or more different approaches have proven to be effective in many studies. Harris and Sanborn-Barrie (2006)1 provide a comprehensive overview of the various modeling approaches.

The Targeting Workflow provides functionality to perform Boolean Logic, Index Overlay, Multi-Class Index Overlay, and Weights-of-Evidence prediction models. Each uses a combination of exploration criteria to generate a prediction model which can be used for targeting XYZ drillhole target positions to be further investigated for mineral potential. Each of the processes implemented here is based on documentation from Bonham-Carter (1994)2.


Report Tree



Targeting Method

Index Overlay involves a combination of weighted binary properties using a simple intersection algorithm where the binary classes (1 or 0) of each property are multiplied by a single weight factor, summed over all properties being combined and normalized by the sum of all weights following the equation:

Weights are defined by the expert and are based on the significance of the evidential property to the exploration model. The result is a weighted score defining favourability of mineral potential. This method allows for a simple ranking of the contributing evidences as a whole.

Targeting Approach Knowledge
Approach LogicWeights of Evidence

Pre-Processing

Evidential Properties

Evidential properties represent the exploration criteria in a targeting model. The Targeting Workflow requires that all evidential properties be prepared and stored as properties on a voxet/sgrid object prior to starting the targeting model process. Properties can be binary, multi-class (categorical) (with or without assigned classification) or continuous in type and will be treating accordingly in the reclassification within the Property Settings step. Although it is not mandatory, it is suggested that multi-class properties be associated with a classification where possible in order to simplify the display of unique classes in the reclassification step and to ease interpretation of units during modeling.
Valid true
Grid/Voxet Name O_Evidence_Layer

PropertyType
AOI_Dehua_MINFILE_showings_dist Continuous
Au_stream_drainage Binary
O_Block_Dike_bends_dist Continuous
O_Block_detailed_contacts_dist Continuous
O_Block_detailed_dikes_dist Continuous
O_Block_detailed_faults_dist Continuous
O_block_AOI_dist Continuous
O_block_contact_bends_dist Continuous
O_block_fault_bends_dist Continuous
O_fault_intersections_dist Continuous
O_mag_anomaly_pinch_outs_dist Continuous
O_mag_highs_dist Continuous
O_rad_anomalies_sigma1 Binary
O_rad_anomalies_sigma2 Binary

Prediction Model Volumes

The prediction model volume represents the '3D study area' within which to perform the modeling. The volumes are defined by the spatial extents of each of the contributing evidential properties taking into account any no data values and inconsistent data coverage between properties. Each model volume (if more than one) represents the volume where the maximum number of contributing evidential properties overlap.
Model Volume Name Model1
Model Volume Region model_region_0
Model Volume 100

Evidential Property Settings

Precombination

This is an optional step which allows the user to pre-combine two or more evidential properties prior to computing the prediction model. Pre-combining datasets will account for evidential properties which are too strongly correlated and would result in an over-biased prediction result.
Generated true
Perform Data Precombination? true

Combination
O_Block_detailed_contacts_and_dikes
O_Block_bends_and_pinch_outs

Evidence Weights

In binary and multi-class Index Overlay models, each evidential property is assigned a weight factor determined by its importance to the exploration model. Multi-Class Index Overlay further weights evidential properties by assigning scores to each of the property classes. Weights and scores are determined by the expert. They should be determined by relative importance (most important evidential property/class assigned the highest weight/score value) and are not restricted to integer values. The user is advised to use similar scoring schemes since scores are not normalized in the Multi-Class Index Overlay algorithm (i.e. scores should not range from 0-1 on one property and 0-10 on another within the same prediction model).
Scores_Out -

PropertyWeight
AOI_Dehua_MINFILE_showings_dist_out 1.5
Au_stream_drainage_out 1.5
O_Block_detailed_faults_dist_out 1.2
O_fault_intersections_dist_out 1.1
O_mag_highs_dist_out 1.1
O_rad_anomalies_sigma1_out 1.15
O_rad_anomalies_sigma2_out 1.3
O_Block_bends_and_pinch_outs 1.1
O_Block_detailed_contacts_and_dikes 1.1

Processing

Prediction Model Generation

At this step in the workflow the knowledge-driven data combination algorithm is executed on the selected evidential properties, taking into account weights and scores if applicable, generating the final prediction model. Multiple prediction models can be generated at this step by selecting various combinations of evidential properties.
ModelName Model1, O_Targeting_Model_Final

ModelPrediction Model Properties
Model1 AOI_Dehua_MINFILE_showings_dist_out, Au_stream_drainage_out, O_Block_Dike_bends_dist_out, O_Block_detailed_contacts_dist_out, O_Block_detailed_dikes_dist_out, O_Block_detailed_faults_dist_out, O_block_AOI_dist_out, O_block_contact_bends_dist_out, O_block_fault_bends_dist_out, O_fault_intersections_dist_out, O_mag_anomaly_pinch_outs_dist_out, O_mag_highs_dist_out, O_rad_anomalies_sigma1_out, O_rad_anomalies_sigma2_out, O_Block_detailed_contacts_and_dikes, O_Block_bends_and_pinch_outs
O_Targeting_Model_Final AOI_Dehua_MINFILE_showings_dist_out, Au_stream_drainage_out, O_Block_detailed_faults_dist_out, O_fault_intersections_dist_out, O_mag_highs_dist_out, O_rad_anomalies_sigma1_out, O_rad_anomalies_sigma2_out, O_Block_detailed_contacts_and_dikes, O_Block_bends_and_pinch_outs

Post-Processing

Targeting

Once the prediction model is generated, the workflow allows for an advanced targeting approach by allowing the user to refine and interpret the model down to the drillhole targets level. The prediction model can be refined by looking only at cells within a specific sub-region of the model, for example, in only the undrilled portion of the model, or within the spatial extents of a claim block area, etc.

A target value cutoff should be applied here which will show only the top percentage of the target result. From this top, typically 1-5%, of data, clusters of values can be generated using a connectivity type factor and ranked based on size. The cells of each cluster can be analyzed separately and the top cells within those clusters can be exported as a set of points representing the XYZ values of your drillhole targets.


Prediction Model Name Model1
Target Cutoff 0.305677977519905 (85.0954%)
Cluster Connectivity Type corners

Target Clusters


Target_RankTarget_VolumeTarget_CellsTarget_MinTarget_MaxTarget_MeanTarget_Median
1 0 422 0.4343891 0.5520362 0.4347956 0.4343891
2 0 4 0.4253394 0.5248869 0.4502262 0.4253394
3 0 5 0.520362 0.520362 0.520362 0.520362
4 0 2 0.4253394 0.4253394 0.4253394 0.4253394
5 0 1 0.4253394 0.4253394 0.4253394 0.4253394
6 0 31 0.4253394 0.6289593 0.5241572 0.5294118
7 0 2 0.5067874 0.5067874 0.5067874 0.5067874
8 0 3 0.4253394 0.4253394 0.4253394 0.4253394
9 0 2 0.520362 0.520362 0.520362 0.520362
10 0 6 0.4253394 0.5248869 0.4419307 0.4253394
11 0 4 0.4253394 0.4253394 0.4253394 0.4253394
12 0 43 0.4253394 0.6289593 0.4601704 0.4253394
13 0 2 0.5248869 0.5248869 0.5248869 0.5248869
14 0 3 0.4253394 0.4253394 0.4253394 0.4253394
15 0 14 0.4253394 0.6289593 0.5420168 0.5294118
16 0 500 0.4253394 0.6606335 0.4661527 0.4343891
17 0 42 0.4253394 0.6244344 0.5337213 0.5067874
18 0 1 0.5248869 0.5248869 0.5248869 0.5248869
19 0 158 0.4253394 0.6289593 0.5022051 0.5067874
20 0 3 0.4253394 0.5248869 0.4917044 0.5248869
21 0 22 0.520362 0.520362 0.520362 0.520362
22 0 57 0.4253394 0.7285068 0.5706122 0.5294118
23 0 31 0.4253394 0.4253394 0.4253395 0.4253394
24 0 16 0.4253394 0.5248869 0.5186653 0.5248869
25 0 21 0.5067874 0.5067874 0.5067874 0.5067874
26 0 43 0.5067874 0.6244344 0.5221511 0.5067874
27 0 1 0.5067874 0.5067874 0.5067874 0.5067874
28 0 11 0.5248869 0.6244344 0.5339367 0.5248869
29 0 28 0.4253394 0.6289593 0.4857791 0.5248869
30 0 39 0.4253394 0.5248869 0.5223345 0.5248869
31 0 5 0.4253394 0.5248869 0.5049773 0.5248869
32 0 3 0.5248869 0.5248869 0.5248869 0.5248869
33 0 79 0.4253394 0.5248869 0.4767742 0.5067874
34 0 7 0.4253394 0.4253394 0.4253394 0.4253394
35 0 9 0.4253394 0.5248869 0.4695827 0.4298643
36 0 2 0.5248869 0.5248869 0.5248869 0.5248869
37 0 11 0.4253394 0.5294118 0.4549568 0.4298643
38 0 39 0.4253394 0.6244344 0.5163015 0.5067874
39 0 12 0.5067874 0.5067874 0.5067874 0.5067874
40 0 66 0.4253394 0.6244344 0.5210477 0.5248869
41 0 34 0.4253394 0.5248869 0.4924142 0.5067874
42 0 12 0.4253394 0.6289593 0.5780542 0.6289593
43 0 7 0.4253394 0.5248869 0.5106658 0.5248869
44 0 7 0.5067874 0.5067874 0.5067874 0.5067874
45 0 1 0.4253394 0.4253394 0.4253394 0.4253394
46 0 3 0.4253394 0.4253394 0.4253394 0.4253394
47 0 15 0.4253394 0.5248869 0.511614 0.5248869
48 0 1 0.5248869 0.5248869 0.5248869 0.5248869
49 0 36 0.4253394 0.5248869 0.4751133 0.4253394
50 0 2 0.5248869 0.5248869 0.5248869 0.5248869
51 0 13 0.4253394 0.5294118 0.4504003 0.4253394
52 0 92 0.4253394 0.6289593 0.4901141 0.520362
53 0 35 0.4253394 0.6289593 0.5137687 0.5248869
54 0 9 0.4253394 0.5248869 0.447461 0.4253394
55 0 15 0.4253394 0.6289593 0.5140272 0.5294118
56 0 74 0.4253394 0.6289593 0.5313075 0.5248869
57 0 3 0.4253394 0.4253394 0.4253394 0.4253394
58 0 55 0.4253394 0.5294118 0.4566022 0.4253394
59 0 12 0.4253394 0.4253394 0.4253394 0.4253394
60 0 2 0.4253394 0.5248869 0.4751132 0.4253394
61 0 1 0.4253394 0.4253394 0.4253394 0.4253394
62 0 11 0.4253394 0.5248869 0.4434389 0.4253394
63 0 1 0.4253394 0.4253394 0.4253394 0.4253394
64 0 63 0.4253394 0.5248869 0.5079368 0.5067874
65 0 10 0.4253394 0.4253394 0.4253394 0.4253394
66 0 12 0.5067874 0.6244344 0.5165913 0.5067874
67 0 6 0.5067874 0.5067874 0.5067874 0.5067874
68 0 3 0.4253394 0.5248869 0.4917044 0.5248869
69 0 1 0.4253394 0.4253394 0.4253394 0.4253394
70 0 2 0.4253394 0.4253394 0.4253394 0.4253394
71 0 45 0.4253394 0.6244344 0.5100051 0.5248869
72 0 2 0.4253394 0.4253394 0.4253394 0.4253394
73 0 9 0.4253394 0.5248869 0.4364003 0.4253394
74 0 12 0.4253394 0.5248869 0.4585219 0.4253394
75 0 144 0.4253394 0.6289593 0.4907302 0.5248869
76 0 13 0.4253394 0.6244344 0.5081796 0.5248869
77 0 243 0.4253394 0.6651584 0.5165262 0.5248869
78 0 4 0.520362 0.520362 0.520362 0.520362
79 0 6 0.4524887 0.4524887 0.4524887 0.4524887
80 0 2 0.4524887 0.4524887 0.4524887 0.4524887
81 0 83 0.4343891 0.6561086 0.5024263 0.520362
82 0 1 0.520362 0.520362 0.520362 0.520362
83 0 64 0.4343891 0.5520362 0.4455599 0.4343891
84 0 27 0.4343891 0.5520362 0.4431037 0.4343891
85 0 90 0.4343891 0.6561086 0.4524387 0.4343891
86 0 55 0.4343891 0.5520362 0.4450843 0.4343891
87 0 14 0.4343891 0.4343891 0.4343891 0.4343891

Drillhole Target Centroids List

The following table displays a list of targets within the Gocad pointset object generated by the 'Add to Centroid Target List' command. These points represent the centroid of the selected Target Cluster. They are ranked by the order they were selected in the Target Clusters Table.


Centroid_IdCentroid_XCentroid_YCentroid_Z
0 381346 6.92193e+06 1401
1 386955 6.93279e+06 1401
2 386568 6.93266e+06 1401
3 386880 6.93246e+06 1401
4 387060 6.93213e+06 1401
5 387360 6.9317e+06 1401
6 393660 6.93138e+06 1401
7 387940 6.93139e+06 1401
8 389310 6.93123e+06 1401
9 387420 6.93102e+06 1401
10 391650 6.93078e+06 1401
11 392353 6.93078e+06 1401
12 388650 6.93057e+06 1401
13 392400 6.93049e+06 1401
14 388024 6.93058e+06 1401
15 394700 6.93118e+06 1401
16 393584 6.93052e+06 1401
17 391980 6.93027e+06 1401
18 390756 6.93065e+06 1401
19 389580 6.93021e+06 1401
20 385415 6.93024e+06 1401
21 393031 6.93027e+06 1401
22 391575 6.93021e+06 1401
23 390038 6.93003e+06 1401
24 388311 6.93008e+06 1401
25 393853 6.92998e+06 1401
26 388380 6.92985e+06 1401
27 393436 6.92982e+06 1401
28 389250 6.93004e+06 1401
29 388671 6.93006e+06 1401
30 387504 6.92978e+06 1401
31 388820 6.92963e+06 1401
32 392365 6.92981e+06 1401
33 388166 6.92951e+06 1401
34 393227 6.92944e+06 1401
35 389670 6.92931e+06 1401
36 391445 6.92921e+06 1401
37 390288 6.92937e+06 1401
38 388550 6.92914e+06 1401
39 394058 6.92941e+06 1401
40 393524 6.92926e+06 1401
41 392220 6.92904e+06 1401
42 388860 6.92901e+06 1401
43 394320 6.92883e+06 1401
44 385200 6.92877e+06 1401
45 392640 6.92865e+06 1401
46 386136 6.92865e+06 1401
47 395580 6.92847e+06 1401
48 386895 6.92859e+06 1401
49 391950 6.92844e+06 1401
50 390231 6.92853e+06 1401
51 389561 6.92891e+06 1401
52 391510 6.92866e+06 1401
53 390620 6.92844e+06 1401
54 392396 6.92834e+06 1401
55 393344 6.92847e+06 1401
56 393400 6.92801e+06 1401
57 391009 6.92838e+06 1401
58 394835 6.92800e+06 1401
59 392850 6.92793e+06 1401
60 391860 6.92793e+06 1401
61 391576 6.92811e+06 1401
62 391080 6.92793e+06 1401
63 394207 6.92813e+06 1401
64 390354 6.9278e+06 1401
65 393390 6.92775e+06 1401
66 393630 6.92766e+06 1401
67 391300 6.92757e+06 1401
68 390360 6.92751e+06 1401
69 390480 6.92742e+06 1401
70 395263 6.92754e+06 1401
71 393600 6.92724e+06 1401
72 394213 6.92724e+06 1401
73 390885 6.92706e+06 1401
74 392591 6.92742e+06 1401
75 393577 6.92655e+06 1401
76 395655 6.9261e+06 1401
77 395010 6.92496e+06 1401
78 395910 6.92485e+06 1401
79 396090 6.92475e+06 1401
80 395524 6.92516e+06 1401
81 395460 6.92421e+06 1401
82 382970 6.9241e+06 1401
83 382696 6.92347e+06 1401
84 381991 6.9233e+06 1401
85 381288 6.92294e+06 1401
86 380576 6.92271e+06 1401

Drillhole Target Cells List

The following table displays a list of targets within the Gocad pointset object generated by the 'Add to Drillhole Target List' command. These points represent the individual cells selected from the target region. They are ranked by the order they were selected in the Property Viewer Table.

References:

1 Harris, J.R., Sanborn-Barrie, M., 2006, Mineral Potential Mapping: Examples from the Red Lake Greenstone Belt, Northwest Ontario, in Harris, J.R., ed., GIS for the Earth Sciences: Geological Association of Canada, Special Publication 44, p. 1-21.

2 Bonham-Carter, G.F., 1994, Geographic Information Systems for Geoscientists: Modeling with GIS: Pergamon, Oxford, 398 p.

3Thiart, C., Bonham-Carter, G.F., Agterberg, F.P., Cheng, Q., and Panahi, A., 2006, An application of the new omnibus test for conditional independence in weights-of-evidence modelling, in Harris, J.R., ed., GIS for the Earth Sciences: Geological Association of Canada, Special Publication 44, p. 131-142.

4 Agterberg, F.P., Bonham-Carter, G.F., Wright, D.F., 1990, Statistical Pattern Integration for Mineral Exploration: in Gaal, G. and Merriam, D.F., ed., Computer Applications in Resource Estimation: Prediction and Assessment for Metals and Petroleum, Pergamon Press, Toronto, p. 1-21.




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