3D GeoModeller Tutorial Case Study G
Contents
1. 3 Highlights drillholes where the difference error exceeds the specified precision Specify a large value for Precision first This enables you to identify the big problems Fix those first Often fixing the big problems automatically fixes some of the smaller problems GeoModeller User Manual Tutorial case study G Drillholes 23 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back G1 Stage 6 Steps 1 From the main menu choose Model gt Compare model with drillhole observations OR From the Model toolbar choose Compare model with drillhole observations 2 For Precision enter 200 Choose OK Highlighted drillholes have model differences compared to the drilled intervals GeoModeller User Manual Tutorial case study G Drillholes 24 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back 3 Fix the problems at the drillholes where 3D GeoModeller has identified a problem You can experiment with adding geology contact or orientation points yourself or follow our solution In section s81N add an orientation point between the third and fourth drillholes from the left to guide the model away from the loop that it is mistakenly generating through the fourth fifth and sixth drillholes Use the steps in G1 Stage 5 Prepare the project for modelling to add the new p2. Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back GeoModeller User Manual Tutorial case study G Drillholes 13 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back 6 Save your project From the main menu choose Project gt Save OR From the Project toolbar choose Save OR Press CTRL S Note that a completed version of Stage 2 of the tutorial is available in GeoModeller tutorial CaseStudyG TutorialG1 Completed_project TutorialG1_1_Load_Holes TutorialG1_1_Load_Holes xml Do not overwrite it G1 Stage 3 Arrange the 2D Viewer windows Parent topic Tutorial G1 Building a model from drillholes erosional series f5 3D GeoModeller has a powerful window arrangement feature For this project it is useful to view all six drill sections in a tiled window arrangement G1 Stage 3 Steps 1 Expand the 2D Viewer so that it occupies about 75 of the main 3D GeoModeller window Drag the border between the 2D Viewer and the 3D Viewer to the right 2 Drag the s91N tab so that it becomes a window above the rest of the 2D Viewer tabs In the 2D Viewer drag the s91N tab down in the 2D Viewer window 3D GeoModeller displays a grey rectangular drop spot This shows the size and position of the new window Drop the s91N tab s91N is now in its own window Drag s91N tab do
3. we model the youngest erosional series first In this tutorial we 1 Import drillhole data 2 Create display and refine the model for one formation Stages in the tutorial G1 Stage 1 Open the prepared 3D GeoModeller Project for Case Study G G1 Stage 2 Import the drillhole data G1 Stage 3 Arrange the 2D Viewer windows G1 Stage 4 Project the Drillholes in each 2D Section View G1 Stage 5 Prepare the project for modelling G1 Stage 6 Comparing the model with drillhole observations G1 Stage 7 Creating a 3D view GeoModeller User Manual Tutorial case study G Drillholes 5 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back G1 Stage 1 Open the prepared 3D GeoModeller Project for Case Study G Parent topic Tutorial G1 Building a model from drillholes erosional series f5 G1 Stage 1 Steps 1 If required save and close any project that you are currently working on 2 From the main menu choose Project gt Open OR From the Project toolbar choose Open OR Press CTRL O Open GeoModeller tutorial CaseStudyG TutorialG1 Beginning_project TutorialG1_Start xml 3 Save the project with a new name in the folder you are using for your tutorial data From the main menu choose Project gt Save As OR From the Project toolbar choose Save As OR Press CTRL SHIFT S Note th
4. You may need to adjust the relative widths of the 2D Viewer windows as you go see step 1 of this stage for instruction 6 Use Zoom Fit section to window in the 2D Toolbar to fit each section view into its window G1 Stage 4 Project the Drillholes in each 2D Section View Parent topic Tutorial G1 Building a model from drillholes erosional series f5 Drillholes are separate data structures within 3D GeoModeller They do not belong to any particular section You can project drillholes onto nearby sections This shows the drillhole geology intervals on the target section in the 2D Viewer G1 Stage 4 Steps 1 In the Model toolbar choose Project data onto section in 2D Viewer 3D GeoModeller displays the Project data onto section dialog box s87N s89N s91N s85N s83N s81N GeoModeller User Manual Tutorial case study G Drillholes 16 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back From the Sections list select all sections s81N s83N s85N s87N s89N and s91N For Maximum distance of projection enter 1 All of the drillholes are exactly on these project sections so this is an appropriate distance Clear from 2D Sections and from Hingelines Check From Drillholes Contacts from3D Points and fromDrillhole Trace Choose Apply GeoModeller User Manual Tutorial case study G Drillholes 17 Contents Help
5. have an onlapping relationship Relationship Onlap to older strata The formations are in a correct stratigraphic order f1 oldest at the bottom of the pile f6 youngest at the top This project uses Bottoms of formations GeoModeller User Manual Tutorial case study G Drillholes 4 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back Strategy for Case Study G Parent topic Case study G Introduction We have found that a useful strategy for building any model in 3D GeoModeller is to 1 Work stratigraphically downwards through the erosional or cross cutting events in this case study first f5 and then f2 2 Work stratigraphically upwards through any onlapping series occurring between these in this case study f3 f4 f6 We recommend this work order because if you model the youngest cross cutting event or geological surface and get get it right all subsequent modelling work on all other older events or surfaces has no impact on that earlier modelling of the younger event Note that this tutorial follows one pathway towards building a 3D model of the Case Study G project geology There are several equally valid alternative approaches Tutorial G1 Building a model from drillholes erosional series f5 Parent topic Tutorial case study G Drillholes According to our strategy see Strategy for Case Study G
6. voxel is in whereas an observation MeshGrid will contain the unit number at each point of the mesh grid 1 Right click on the inv_log_gold MeshGrid and from the context menu select Add Current Model Field You should then see in your Project Tree the new field Current_Model_Grid 2 Right click on the inv_log_gold MeshGrid to open the context menu and choose Compute New Field 3 In the Calculator Dialog perform the following steps 1 Choose IF from the Function Keys GeoModeller User Manual Tutorial G6 Import Drillhole Assay Data 45 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back 2 Choose Current_Model_Grid from the Field List 3 Choose from the Function Keys followed by 3 from the Numeric Keys 4 Choose from the Numeric Keys 5 Choose interp_Au from the Field List 6 Choose from the Numeric Keys 7 Choose NaN from the Numeric Keys 8 Chosoe from the Function Keys 9 Enter the result field name as interp_Au_f3 10 Choose Evaluate followed by Save and Exit The expression should look like the one above It simply says IF voxel lithology is f3 THEN output interp_Au ELSE output null 4 Visualise the new field using the Field Visualisation Manager via the context menu of the interp_Au_f3 field In the dialog choose View Grid in 3D and 3D Volume The visualisation now shows interpolat
7. GeoModeller User Manual Tutorial case study G Drillholes 1 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back Tutorial case study G Drillholes Parent topic User Manual and Tutorials Author Philip McInerney Intrepid Geophysics V2012 Des FitzGerald Editor David Stephensen www qdt com au Using Drillholes in 3D GeoModeller a Model Building Strategy In this case study Case study G Introduction Tutorial G1 Building a model from drillholes erosional series f5 Tutorial G2 Building a model from drillholes erosional series f2 Tutorial G3 Building a model from drillholes onlapping series f3 Tutorial G4 Building a model from drillholes onlapping series f4 Tutorial G5 Building a model from drillholes onlapping series f6 GeoModeller User Manual Tutorial case study G Drillholes 2 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back Case study G Introduction Parent topic Tutorial case study G Drillholes In this section Project data preparation Topography of Case Study G Geology of Case Study G Strategy for Case Study G Project data preparation Parent topic Case study G Introduction For this tutorial we have created a project area containing synthetic geolo
8. Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back 2 3D GeoModeller displays the projected drillholes 3 Choose Close G1 Stage 5 Prepare the project for modelling Parent topic Tutorial G1 Building a model from drillholes erosional series f5 The first task in this tutorial is to model formation f5 To model any geology surface 3D GeoModeller requires the following At least one contact point for each formation within a series AND At least one point of orientation data for one of the formations within the series In our case we have no contact points as such However 3D GeoModeller automatically extracts valid contact points from the geology intervals described in the drillhole data It turns out that there are numerous contact points in the assemblage of 40 drillholes imported here Note 3D GeoModeller may not necessarily find a geology contact from drill hole data If it cannot then you must supply your own contact points before it can compute the series There are no orientation data in the project yet 3D GeoModeller requires orientation data before it can compute a series Perhaps you have some measured structural data for the f5 series You could import that data In the absence of measured data we can provide an interpreted piece of orientation data We shall examine the drill hole data made available to us in the section views and d
9. at a completed version of Stage 2 of the tutorial is available in GeoModeller tutorial CaseStudyG TutorialG1 Completed_project TutorialG1_1_Load_Holes TutorialG1_1_Load_Holes xml Do not overwrite it G1 Stage 1 Discussion and exploration To view the formations from the main menu choose Geology gt Formations Create or Edit To view the whole stratigraphic pile from the main menu choose Geology gt Stratigraphic Pile Visualise GeoModeller User Manual Tutorial case study G Drillholes 6 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back G1 Stage 2 Import the drillhole data Parent topic Tutorial G1 Building a model from drillholes erosional series f5 Our contractor has drilled a set of 40 deep vertical holes on the six sections These holes are 4500 m deep nice drilling budget and there are about six holes per section The sections are 2000 m apart and the holes are at various spacings 600 m 1800 m The drillhole data are in a commonly used drillhole data file format This is a set of three files containing the drillhole collars surveys and geology For interest you could examine these files in a text editor For example you could examine GeoModeller tutorial CaseStudyG TutorialG1 Data Drilling VDH40Holes_Geology csv The first line of each file gives field names for each column of data You need to set these field na
10. ecide where we can reasonably estimate the attitude of the bottom of the f5 boundary After locating this we enter an orientation data point describing that attitude In this tutorial we place the interpreted orientation data point on Section s81N GeoModeller User Manual Tutorial case study G Drillholes 18 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back G1 Stage 5 Steps 1 Select the s81N section in the 2D Viewer In the Points List toolbar Choose Delete all Points to erase any contents of the Points List Choose Create OR press C 2 Click the bottom of the f5 pink formation on the first drillhole This is the location of the orientation data point that you are creating Click the bottom of the f5 pink formation on the second drillhole This indicates the dip of the orientation point Click 2 Click 1 GeoModeller User Manual Tutorial case study G Drillholes 19 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back 3 In the Structural toolbar choose Create geology orientation data From Geological formations and faults select f5 From Provenance select Interpreted Choose Create 4 Check the orientation data point The shaft of the T shape should point up in the section If it points down edit the point and reverse the Polari
11. ed GeoModeller User Manual Tutorial case study G Drillholes 8 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back 5 Select the correct data file field name from the drop down lists for each 3D GeoModeller field name in the dialog boxes using the results of your examination above or the names shown in the data preview panels shown below Choose Next GeoModeller User Manual Tutorial case study G Drillholes 9 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back Choose Next Choose Next Choose Next GeoModeller User Manual Tutorial case study G Drillholes 10 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back Note of course that the lithology coding in the geology file must correspond to geology formations defined in the 3D GeoModeller project Choose Next GeoModeller User Manual Tutorial case study G Drillholes 11 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back Choose Next Choose Finish View the 40 drillholes in the 3D Viewer If not already displayed In the Project Explorer from the Drillholes shortcut menu choose Show GeoModeller User Manual Tutorial case study G Drillholes 12
12. ed gold data within the lithology unit of interest You can view the colour map via the context menu for the field interp_Au_f3 Choose Edit Colours and Clips GeoModeller User Manual Tutorial G6 Import Drillhole Assay Data 46 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back Estimate the volume of gold within the f3 unit 1 To get an estimate of the volume with the f3 unit you can use the MeshGrid Calculator again Open the calculator from the context menu of inv_log_gold 2 Create the expression IF interp_Au_f3 lt gt NaN Current_Model_Grid NaN using the keys and field list 3 Enter the name of the new field as interp_Au_f3_lithology 4 Choose Evaluate followed by Save and Exit Check that the field was created in the project tree 5 Right click on the new field interp_Au_f3_lithology and choose Properties This will open the properties dialog 6 In the dialog change the Alias from none to Lithology Choose OK GeoModeller will now recognise this field as a lithology field 7 Open the context menu for the field interp_Au_f3_lithology and choose Histogram This will display the histogram together with the volume of voxels GeoModeller User Manual Tutorial G6 Import Drillhole Assay Data 47 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back which contain go
13. enuine errors You can review the project geology and add further geology observations or interpretations to seek to resolve the reported discrepancies At smaller Precision values the errors may be due to the mathematical uncertainty in the model You would gain very little from further interpretive work to try and resolve such relatively small errors small relative to the overall dimensions of the model project GeoModeller User Manual Tutorial case study G Drillholes 27 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back G1 Stage 7 Creating a 3D view Parent topic Tutorial G1 Building a model from drillholes erosional series f5 When you are satisfied that you have modelled the f5 surface in a credible geological manner and that the model is consistent with the drilled geology intervals you can quickly generate a 3D surface and view this in the 3D Viewer G1 stage8 Steps 1 View the 40 drillholes in the 3D Viewer If not already displayed In the Project Explorer from the Drillholes shortcut menu choose Show 2 Choose main menu Model gt Build 3D formations and faults OR In the Model toolbar choose Build 3D formations and faults Check Surface and choose OK To change the colour of the surface in the Project Explorer from the shortcut menu of Model gt Surface f1_f5 choose Appearance Note that a completed version o
14. f Stage 8 of the tutorial is available in GeoModeller tutorial CaseStudyG TutorialG1 Completed_project TutorialG1_2_f5 TutorialG1_2_f5 xml Do not overwrite it Here is an illustration of the completed Tutorial G2 project GeoModeller User Manual Tutorial case study G Drillholes 28 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back Tutorial G2 Building a model from drillholes erosional series f2 Parent topic Tutorial case study G Drillholes In this tutorial we create display and refine the model for erosional series f2 After series f5 Tutorial G1 Building a model from drillholes erosional series f5 series f2 is the next older erosional surface and the next series for modelling see Strategy for Case Study G Repeat the steps from Tutorial G1 Building a model from drillholes erosional series f5 but for section f2 1 Start with your completed project from G1 Stage 6 Comparing the model with drillhole observations or open the completed version that we have supplied GeoModeller tutorial CaseStudyG TutorialG1 Completed_project TutorialG1_2_f5 TutorialG1_2_f5 xml 2 Start repeating the steps from G1 Stage 4 Project the Drillholes in each 2D Section View 3 Continue to the end of G1 Stage 7 Creating a 3D view Note that a completed version of this tutorial is available in GeoModeller tutorial CaseStudyG TutorialG2 Com
15. gy We have prepared a beginning project file for this case study You open it at the start of Tutorial G1 Building a model from drillholes erosional series f5 We have Defined the project dimensions Created a 3D GeoModeller project using these extents Loaded a digital terrain model DTM grid to create the topography for the project See Topography of Case Study G for details Created an initial stratigraphic pile The top or bottom reference for the pile is Bottom of formations See Geology of Case Study G for details Created a series of sections s81N s83N s85N s87N s89N s91N Minimum Maximum Range East 483 100 491 700 8 600 m North 4 280 700 4 291 500 10 800 m RL 2000 4000 6000 m GeoModeller User Manual Tutorial case study G Drillholes 3 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back Topography of Case Study G Parent topic Case study G Introduction The following illustration shows the topography of the Case Study G region Geology of Case Study G Parent topic Case study G Introduction The following illustration shows the geology of the case study region Notes about the project There are six formations f1 f2 f3 f4 f5 and f6 in a roughly layered sequence Two of the units are erosional Relationship Erode across the older strata and the other units
16. he histogram dialog which also contains summary statistics GeoModeller User Manual Tutorial G6 Import Drillhole Assay Data 43 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back 4 Now display the voxet in the 3D viewer Right click on the interp_Au field and choose Field Visualisation Manager to show the visualisation dialog For now just select View Grid in 3D as a 3D Volume Because we know that the gold is all in the f3 unit we have shown it here as a wireframe You will notice immediately that the interpolation is not contrained to this unit It is for this purpose that you would choose Domain Kriging However we can still visualise and perform processing on the inverse distance interpolated data which only falls within the unit f3 To do this two steps additional steps are required GeoModeller User Manual Tutorial G6 Import Drillhole Assay Data 44 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back 1 Add a model field to the MeshGrid 2 Threshold the interp_Au field to only those voxels within the f3 unit using the model field Adding a model field to a MeshGrid Any MeshGrid can have a model field added to it A model field is a lithology field that contains the units at each cell in a MeshGrid For example a voxet model field will the lithology unit number that each
17. kets 4 Change the Result Field Name to log_au or something appropraite 5 Choose Evaluate to evaluate the expression and create the new field 6 Choose Save and Exit to save the results into the Projet tree Important You must always Evaluate the expression before choosing Save and Exit Otherwise the result will not be saved in the Project Tree You should now have two fields in the MeshGrid as shown GeoModeller User Manual Tutorial G6 Import Drillhole Assay Data 39 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back Inverse Distance Interpolation 1 Right click on the log_au field to open the MeshGrid field context menu Choose Inverse Distance Interpolation 2 In the dialog choose New Grid and enter the name of the grid Here it is shown as inv_log_gold GeoModeller User Manual Tutorial G6 Import Drillhole Assay Data 40 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back Choose Next to move to the next page of the wizard 3 On the next page under Grid Definition choose Fixed and enter 250m cell spacing Then specify the Maximum Radius of Neighbourhood as 3000 metres Choose Next to go to page 3 of the wizard 4 Enter the name of the interpolation field In this example it is called interp_log_au GeoModeller User Manual Tutorial G6 Import Dri
18. ld interpolated for the unit f3 Compare this number with the value from the Current_Model_Grid field The volume of unit f3 is 4 604688E10 m The volume of unit f3 which contains interpolated gold is 3 107812E10 m3 This does not show an estimate of the grade of the gold in the f3 unit just the cells which contain gold
19. llhole Assay Data 41 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back Choose Finish to perform the interpolation You should now have a new MeshGrid in your project called inv_log_gold or whatever name you chose of page 1 of the wizard This grid is a regular voxet with fixed cell size of 250m Remove linearisation of the interpolated field Recall that the interpolation was performed on the log of the gold assay data Now you will need to remove the linearisation to revert back to a log normal distribution 1 Right click on the inv_log_gold and choose Compute New Field This will open the calculator dialog box again 2 In the calculator perform the following steps 1 Choose exp from the Function Keys 2 Choose interp_log_au from the Field List 3 Choose to close the brackets 4 Enter the name for the new field Here it is specified as interp_Au GeoModeller User Manual Tutorial G6 Import Drillhole Assay Data 42 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back 5 Choose Evaluate followed by Save and Exit You should now have the new field interp_Au in your project MeshGrid inv_log_gold 3 Explore the field interp_Au by looking at the histogram and statistics Right click on the field and choose Histogram from the context menu This will bring up t
20. mes in 3D GeoModeller when you import the drillhole data The following table contains the field name list for each file G1 Stage 2 Steps 1 Ensure that you are using your own saved version of the project according to G1 Stage 1 Open the prepared 3D GeoModeller Project for Case Study G Do not overwrite the completed version of this tutorial that we have supplied in your 3D GeoModeller installation 2 From the main menu choose Import gt Import drillhole data gt Import collars surveys geology 3 files This starts the CSV Data Import 3 table Collar Survey Geology Drillholes wizard as shown below File Field names VDH40Holes_Collars csv HoleID X Y Z EOH_Depth VDH_s81N_01 483500 4281000 2755 4500 VDH_s81N_04 485300 4281000 2761 4500 VDH40Holes_Survey csv HoleID Dip Azimuth Depth VDH_s81N_01 90 0 0 VDH_s81N_01 90 0 4500 VDH40Holes_Geology csv HoleID From To Lithology VDH_s81N_01 0 743 f6 VDH_s81N_01 743 2380 f5 GeoModeller User Manual Tutorial case study G Drillholes 7 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back 3 In the first page of the CSV Data Import 3 table wizard dialog box choose Browse for the Collar Table and locate the drillhole collars file GeoModeller tutorial CaseStudyG TutorialG1 Data Drilling VDH40Holes_Collars csv 4 Repeat step 2 for Survey Table and Geology Table correspondingly nam
21. oint recalculate and replot the model Compare the model with drillhole observations again with a distance of 200 m Add further points in other sections as required Recalculate The illustration below shows the steps and the result In this illustration we have removed discrepancies in the model to an accuracy of 200 m 1 Model has loop 2 Click trace points 3 Create orientation point 4 Recalculate model 5 Add orientation points in other sections as necessary and recalculate GeoModeller User Manual Tutorial case study G Drillholes 25 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back 4 Compare the model with drillhole observations using progressively finer precision 50 m then 15 m then 5 m repeating steps 1 3 At 50 m we added orientation points to s81N and s91N When we recalculated the model we found another problem in s85N which we fixed The results are in the illustration below GeoModeller User Manual Tutorial case study G Drillholes 26 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back As you work through the problems in the model the interpreted horizon begins to look more plausible Important note about 3D GeoModeller s Compare the model with drillhole observations feature At larger Precision values 3D GeoModeller calculates g
22. ose Plot the model on all sections G1 Stage 5 Discussion Note that 3D GeoModeller only calculates and plots the model for formation f5 To calculate the model for a formation 3D GeoModeller requires that there be at least one orientation point associated with it Currently f5 is the only formation that matches this criterion At these early stages of modelling a surface you may get unexpected results This is mainly because there is very little orientation data to give information about the attitude of the geology surfaces In the following stage we shall work through the issues dealing with the biggest problems first GeoModeller User Manual Tutorial case study G Drillholes 22 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back G1 Stage 6 Comparing the model with drillhole observations Parent topic Tutorial G1 Building a model from drillholes erosional series f5 Note Using 3D GeoModeller s Compare the model with drillhole observations feature is a useful tool but it is not required or obligatory in this case study You may be able to find and fix problems with the model just as easily using enlarged views and examining the graphic representation When using drillholes since the contact point from the data is certain we would expect 3D GeoModeller to place the geology boundary from the model exactly at this point Some
23. pleted_project TutorialG2_f5f2 TutorialG2_f5f2 xml Do not overwrite it Here is an illustration of the completed Tutorial G2 project GeoModeller User Manual Tutorial case study G Drillholes 29 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back Tutorial G3 Building a model from drillholes onlapping series f3 Parent topic Tutorial case study G Drillholes In this tutorial we create display and refine the model for onlapping series f3 Now that we have modelled the erosional series we are ready to model serties f3 the oldest onlapping series see Strategy for Case Study G Repeat the steps from Tutorial G1 Building a model from drillholes erosional series f5 but for section f3 1 Start with your completed project from Tutorial G2 Building a model from drillholes erosional series f2 or open the completed version that we have supplied GeoModeller tutorial CaseStudyG TutorialG2 Completed_project TutorialG2_f5f2 TutorialG2_f5f2 xml 2 Start repeating the steps from G1 Stage 4 Project the Drillholes in each 2D Section View Note that a completed version of this tutorial is available in GeoModeller tutorial CaseStudyG TutorialG3 Completed_project TutorialG3_f5f2f3 TutorialG3_f5f2f3 xml Do not overwrite it Here is an illustration of the completed Tutorial G3 project GeoModeller User Manual Tutorial case study G Drillhole
24. s 30 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back Tutorial G4 Building a model from drillholes onlapping series f4 Parent topic Tutorial case study G Drillholes In this tutorial we create display and refine the model for onlapping series f4 After series f3 series f4 is the next youngest onlapping surface and the recommended next series for modelling see Strategy for Case Study G Repeat the steps from Tutorial G1 Building a model from drillholes erosional series f5 but for section f4 1 Start with your completed project from Tutorial G3 Building a model from drillholes onlapping series f3 or open the completed version that we have supplied GeoModeller tutorial CaseStudyG TutorialG3 Completed_project TutorialG3_f5f2f3 TutorialG3_f5f2f3 xml 2 Start repeating the steps from G1 Stage 4 Project the Drillholes in each 2D Section View 3 Continue to the end of G1 Stage 7 Creating a 3D view Note that a completed version of this tutorial is available in GeoModeller tutorial CaseStudyG TutorialG4 Completed_project TutorialG4_f5f2f3f4 TutorialG4_f5f2f3f4 xml Do not overwrite it Here is an illustration of the completed Tutorial G4 project GeoModeller User Manual Tutorial case study G Drillholes 31 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty L
25. s Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back mouse 3 Choose Edit to open the Drillhole Properties Dialog This dialog shows the drillhole log in the tree on the left hand side The columns next to this highlight the drillhole log geological model misfit and the assay field plot As can be seen here there is now assay data in this drillhole GeoModeller User Manual Tutorial G6 Import Drillhole Assay Data 36 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back Tutorial G6 Assay Data to Observation MeshGrid Once assay data has been imported into drillholes you will generally want to perform some sort of interpolation analsysis or processing To do this in GeoModeller v2012 you must first create an Observation MeshGrid from Drillhole fields 1 Right click on the Drillholes entry in the project tree to bring up the context menu 2 Select Fields to Data Points Mesh to bring up the filter dialog 3 Choose Select All for both the drillholes left side and Fields right side Then choose OK to close the dialog and create the MeshGrid GeoModeller User Manual Tutorial G6 Import Drillhole Assay Data 37 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back You should now see the MeshGrid in the Project tree This tutorial will not cover
26. t Drillhole Assay Data 1 Choose Import gt Drillhole gt Assay Data into Existing Drillholes 2 The Import ASCII Wizard will pop up 1 On the first page select the input file GeoModeller User Manual Tutorial G6 Import Drillhole Assay Data 33 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back GeoModeller tutorial CaseStudyG TutorialG5 Data AssayImport Example csv 2 On the second page you will see the file is formatted correctly already Choose Next to go to page 3 3 Set the column mapping for the Hold ID 3 Set the column mapping for the From and To in the same manner 4 Set the Au field paraters Set the Type to Real set the name description and units as desired The default NULL value can be used GeoModeller User Manual Tutorial G6 Import Drillhole Assay Data 34 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back 5 Choose Finish to close the wizard and import the data Tutorial G6 Drillhole Properties Dialog To view the assay field data for a drillhole you can use the Drillhole Properties Dialog 1 Expand the Drillhole list in the Project Explorer tree 2 Find Drillhole VDH_s87N_07 in the list and open its context menu using the GeoModeller User Manual Tutorial G6 Import Drillhole Assay Data 35 Contents Help Top Back Content
27. td Back Tutorial G5 Building a model from drillholes onlapping series f6 Parent topic Tutorial case study G Drillholes In this tutorial we create display and refine the model for the final onlapping series f6 After series f4 series f6 is the next youngest onlapping surface and the next series for modelling see Strategy for Case Study G Repeat the steps from Tutorial G1 Building a model from drillholes erosional series f5 but for section f4 1 Start with your completed project from Tutorial G4 Building a model from drillholes onlapping series f4 or open the completed version that we have supplied GeoModeller tutorial CaseStudyG TutorialG4 Completed_project TutorialG4_f5f2f3f4 TutorialG4_f5f2f3f4 xml 2 Start repeating the steps from G1 Stage 4 Project the Drillholes in each 2D Section View 3 Continue to the end of G1 Stage 7 Creating a 3D view Note that a completed version of this tutorial is available in GeoModeller tutorial CaseStudyG TutorialG5 Completed_project TutorialG5_f5f2f3f6 TutorialG5_f5f2f3f6 xml Do not overwrite it Here is an illustration of the completed Tutorial G4 project GeoModeller User Manual Tutorial G6 Import Drillhole Assay Data 32 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back The following illustrations are of the final model using line and filled mode Tutorial G6 Impor
28. the vast number of tools available when working with MeshGrids Instead a very simple quick preview interpolation of the assay data using Inverse Distance Interpolation will be shown NOTE GeoModeller v2012 now supports both traditional Kriging and domain Kriging Kriging can provide much better results than the Inverse Distance interpolation Tutorial G7 Inverse Distance Interpolation In this exercise you will Compute a new MeshGrid field using the MeshGrid calculator Interpolate data in a MeshGrid field using Inverse Distance Interpolation Add your Geological model as a field to an existing MeshGrid Use the calculator to threshold field data by unit It is common for Gold data to have a log normal distribution For interpolation it is desirable to normalise the distribution first Therefore the first step in this exercise is to use the MeshGrid calculator to take the LOG of the Gold field Au GeoModeller User Manual Tutorial G6 Import Drillhole Assay Data 38 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back Compute the LOG of a MeshGrid field 1 Right click on the MeshGrid DrillholeFields and choose Compute New Field from the context menu 2 In the calculator dialog 1 Choose ln natural log from the Function Keys 2 Choose Au from the Field List 3 Choose from the Function Keys to close the brac
29. times 3D GeoModeller places a geology boundary through the middle of some drilled geology interval Sometimes also the model surface appears to meander This is because 3D GeoModeller is using two other techniques that may from its viewpoint conflict with the drillhole data It is trying to keep the model surface smooth It is using geological statistics to predict the course of the boundary These problems typically occur at the hole collar and near the end of hole The problems are occurring at places where 3D GeoModeller does not have enough information to generate the model properly To fix the problems add geology contact or orientation points As interpreters we influence the modelling calculation according to our belief about the geology We can do this by Tracing out a line of points where we believe the geology should be OR Add orientation data to influence the attitude of the geology horizons Note that that we may not necessarily correct the data at the location of the error The error may result from lack of orientation data at a neighbouring drillhole We could even add mapping data on the surface that would resolve the problem Comparing the model with drillhole observations gives information about the location of the problems It does the following 1 Examines each interval of observed geology from the drillhole data 2 Checks the model s predicted geology over the same interval
30. ty To edit the point point to it so that it turns white From the shortcut right click menu choose Edit In the Create geology orientation data dialog box from the Polarity options select Normal or Reverse whichever is not selected Choose Edit Close the Create geology orientation data dialog box GeoModeller User Manual Tutorial case study G Drillholes 20 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back 5 Compute the model with all series and sections From the main menu choose Model gt Compute OR From the Model toolbar choose OR Press CTRL M For Series to interpolate Sections to take into account and Drillholes to take into account choose Select All Choose OK GeoModeller User Manual Tutorial case study G Drillholes 21 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back 6 Plot the model with lines in each of the section views From the main menu choose choose Model gt Plot the model settings OR From the Model toolbar choose Plot the model settings OR Pess CTRL D From the Section drop down list select a section Check Show lines and clear Show fill Choose OK 3D GeoModeller plots the model on the selected section From the main menu choose choose Model gt Plot the model on all sections OR From the Model toolbar cho
31. wn and drop Horizontal split s91N GeoModeller User Manual Tutorial case study G Drillholes 14 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back 3 Drag the s89N tab to become a tab in the s91N window In the 2D Viewer drag the s89N tab to the middle of the of the s91N window 3D GeoModeller displays a grey rectangular drop spot that covers the whole s91N window If a half sized drop spot appears drag the tab further up or down until you see a full sized drop spot Drop the s89N tab s89N is now a tab of the upper window 4 Drag the s91N tab into its own window at the right separating it from the s89N window In the 2D Viewer drag the s91N tab to the right border of the upper window 3D GeoModeller displays a grey rectangular drop spot This shows the size and position of the new window Drop the s91N tab s91N now has its own window to the right of s89N Drop spot is anywhere in top window Drag s89N tab to top window and drop Two tabs in top window s91N amp s89N Drag s89N tab to right edge and drop Drop spot Top window split s91N s89N GeoModeller User Manual Tutorial case study G Drillholes 15 Contents Help Top Back Contents Help Top 2013 BRGM amp Desmond Fitzgerald amp Associates Pty Ltd Back 5 Continue using this technique and create the window arrangement shown in the illustraton below
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