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Product GEOVIA Minex 6.4 Last modified: Tuesday, 19 August 2014 Open pit design tutorial Table of Contents About this document ................................................................................................................ 5 Document conventions ............................................................................................................ 6 Typographical conventions .................................................................................................................... 6 Keyboard conventions ........................................................................................................................... 6 Menu conventions .................................................................................................................................. 6 Mouse conventions ................................................................................................................................ 6 Form elements ....................................................................................................................................... 7 Concepts ................................................................................................................................... 9 Benches ................................................................................................................................................. 9 Strips .................................................................................................................................................... 11 Blocks .................................................................................................................................................. 12 Setup for this tutorial ............................................................................................................. 14 Activity: Install the data set .................................................................................................................. 14 Activity: Back up the data set .............................................................................................................. 14 Activity: Create a Minex project ........................................................................................................... 14 Merging ................................................................................................................................... 17 Activity: Create merged grids for weathering ....................................................................................... 17 Activity: View the difference between a merged grid and a model grid ............................................... 18 Activity: Show a grid for reference ....................................................................................................... 19 OP design overview ............................................................................................................... 24 Pit boundary, bench grids, and bench list ............................................................................ 25 Activity: Create bench grids ................................................................................................................. 25 Activity: Create a bench list ................................................................................................................. 28 Benches .................................................................................................................................. 30 Activity: Plot geometry data ................................................................................................................. 32 Activity: Create benches for a pit (without a ramp) .............................................................................. 35 Activity: Design a pit using automatic pit projection ............................................................................ 36 Activity: Add benches manually. .......................................................................................................... 39 Activity: Copy the pit floor into pit 2 ..................................................................................................... 40 Activity: Design a pit using manual pit projection ................................................................................ 41 Activity: Use the Insitu Resource Report to see the volume, tonnage, and strip ratio for a pit ........... 45 Strips ....................................................................................................................................... 48 Activity: Create strips ........................................................................................................................... 49 Activity: Project the strips ..................................................................................................................... 51 Activity: Digitize a missing strip at the crest ......................................................................................... 54 Ramps ..................................................................................................................................... 56 Activity: Create benches for a pit (with a ramp) ................................................................................... 56 Activity: Correct any ramp points lost errors ..................................................................................... 59 Blocks ..................................................................................................................................... 61 Activity: Create blocks ......................................................................................................................... 63 Activity: Validate blocks and fix errors ................................................................................................. 66 Activity: Validate blocks ....................................................................................................................... 70 Activity: Drag centroids inside their respective blocks ......................................................................... 72 Activity: Fix crossed strip lines ............................................................................................................. 72 Activity: Fix layout lines ........................................................................................................................ 72 Activity: Delete blocks outside the pit .................................................................................................. 72 Summary ................................................................................................................................. 73 Appendix A: Merging theory .................................................................................................. 74 About this documentTypographical conventions GEOVIA Minex 6.4Page 5 of 78Open Pit Design tutorial About this document This tutorial introduces the concept of the Minex pit design feature. You can use the Minex pit design feature to design pits with strip and block divisions for an open cut stratified deposit. This tutorial uses a data set that is copied to your computer when Minex is installed. Whenthesoftwarehasbeeninstalled,moredetailedinformationisavailableintheMinexHelp,which you can open from the Help menu. You can also contact your local GEOVIA support office for training. Requirements Before proceeding with this tutorial, you will need: a good understanding of basic Minex concepts Note: This tutorial assumes that you have completed the Minex Core tutorial. Minex 6.4 or later installed the Pit Design data set a licence for the Open Pit moduleObjectives After working through this tutorial, you will be able to: correct holes in grids create merged grids determine a pit boundary create bench grids create a bench list show and hide elements of a pit using the Geometry Display form create the benches of a pit, with or without a ramp create strips, including strip ends create and validate blocks Document conventionsTypographical conventions GEOVIA Minex 6.4Page 6 of 78Open Pit Design tutorial Document conventions Typographical conventionsSome text in this guide has special formatting to help you identify it as part of a particular element of information. The following table describes the different text formats and their meanings.Text format Meaning Text or data that varies with each input is shown in bold italic font and enclosed in angle brackets. Some examples are installation directories, dates, names, and passwords. When you substitute the text for the variable, do not include the brackets. For example: requires you to substitute a password in place of . ItalicsA word or phrase to which the author wants to give emphasis. For example: you must select an item from the list to continue. BoldThis typeface indicates one of the following: A file name, path, or URL. Strongly emphasized text. For example, It is very important to save the data []. Text that a procedure has instructed you to type. A menu option, tab, button, check box, list, option button, text box, or icon. For example: Save the file as pit1.str. Keyboard conventionsKey combination Meaning+Press and hold the first key, then press the second key. For example: CTRL+Z means press and hold the CTRL key, then press Z. Menu conventions When you click, or move the pointer over, some menu commands, a subordinate menu appears. To indicate that you should select a command on a subordinate menu, this documentation uses a greater than (>) sign to separate the main menu command from the subordinate menu command. For example, File > Project > Project Manager means choose the File menu, move the mouse pointer over the Project command, and then select Project Manager on the secondary menu. Mouse conventionsAction DescriptionClickPress and release the left mouse button without moving the mouse. Right-clickPress and release the right mouse button without moving the mouse. Double-clickRapidly click the left mouse button twice without moving the mouse. Drag With the mouse pointer over the object, press and hold the left mouse button to select the object. Move the pointer until the object is in the position you want, and then release the mouse button. RotateUse your finger to make the wheel button roll. Move it forward, that is in a clockwise direction, or backward, that is in an anticlockwise direction. Document conventionsForm elements GEOVIA Minex 6.4Page 7 of 78Open Pit Design tutorial Form elements Forms, or dialog boxes, can contain a variety of elements that enable users to carry out operations. Here is an example form. Forms can contain the following elements Element Description Example TitleTitle of the form. TabLabelled group of options used for many similar kinds of settings. Text box or field Rectangular box in which you can type text. If the box already contains text, you can select that text and edit it. Drop-down combo box Closed version of a list box with an arrow next to it. Clicking the arrow opens the list. Option buttonRound button you can use to select one of a group of mutually exclusive options. Label Text attached to any option, box, button, or to any other element of a window or dialog box. Check box Square box that you select or clear to turn an option on or off. ButtonRectangular or square button that runs a command. Buttons have text labels to indicate their purpose. IconA graphical button that you can click to run a command. List boxAny type of box containing a selectable list of items in table format. Document conventionsForm elements GEOVIA Minex 6.4Page 8 of 78Open Pit Design tutorial Element Description ExampleMenuA set of options or commands that you can run. Spin boxA text box with up and down arrows that you can click to move through a set of fixed values. You can also type a valid value in the box. TreeA graphical representation of a hierarchical structure. A plus sign next to an item on the tree indicates that you can expand the item to show subordinate items; a minus sign indicates that you can collapse the item. ConceptsBenches GEOVIA Minex 6.4Page 9 of 78Open Pit Design tutorial Concepts Pit design theory As part of the pit design process, you will create: benches strips blocks Benches Benches break geology vertically ConceptsBenches GEOVIA Minex 6.4Page 10 of 78Open Pit Design tutorial ConceptsStrips GEOVIA Minex 6.4Page 11 of 78Open Pit Design tutorial Strips ConceptsBlocks GEOVIA Minex 6.4Page 12 of 78Open Pit Design tutorial Strips Blocks Blocks ConceptsBlocks GEOVIA Minex 6.4Page 13 of 78Open Pit Design tutorial Setup for this tutorialActivity: Install the data set GEOVIA Minex 6.4Page 14 of 78Open Pit Design tutorial Setup for this tutorial Tutorial data When you install Minex and accept the default installation settings, the tutorial data is installed on your machine. If you choose not to install the tutorial data sets when installing Minex, you can install them separately. Activity: Install the data set 1.Double-click the MinexInstallation.msi file on the installation CD.2.At the Welcome message, click Next.3.Select Modify, and click Next.Minex displays the Custom Setup options. 4.Click the icon next to the Tutorial Data Sets option and select Will be installed on local hard drive.5.Click Next, and follow the remaining installation messages.Data set location The data set is installed to the following location by default: Operating systemLocation Windows 7 or Windows 8.1 C:\Users\Public\GEOVIA\GEOVIA Minex\6x\shared\tutorialData\Datasets\Pit_Design\ Activity: Back up the data set It is a good idea to keep a backup copy of the data in case you want to restart the tutorial with a fresh set of data later. 1.Start Windows Explorer. 2.Browse to the data set. 3.Right-click the Pit_Design folder, and choose Send To > Compressed (zipped) folder. 4.In Windows Explorer, make a new folder for backups, for example C:\minexBackups, and copy the zip file to that folder. Create a Minex project To make it easy to work with your data, you will create a Minex project and set the working directory to the location of the tutorial data (Pit_Design).Activity: Create a Minex project 1.Start Minex. 2.Select File > Project > Project Manager. 3.Click New. 4.In the Project Name field, type PitDesignTutorial. Setup for this tutorialActivity: Create a Minex project GEOVIA Minex 6.4Page 15 of 78Open Pit Design tutorial 5.Browse to the Pit_Design folder. 6.Click Finish. 7.The project is set up and the Minex Explorer displays the Pit_Design folder and subfolders. Note: If you use Hub to manage your files, Hub status icons are displayed beside the files in the Minex Explorer. For this tutorial, Hub status icons are not shown. For more information on Hub, refer to the Help, or the Hub training guide available with the Minex tutorials. Setup for this tutorialActivity: Create a Minex project GEOVIA Minex 6.4Page 16 of 78Open Pit Design tutorial Tip:In the Minex Explorer you can select the top level folder, which is Pit_Design for this project, look at the Properties pane, and see the full path of the project. This is useful if you forget, or want to verify, where the data is. MergingActivity: Create merged grids for weathering GEOVIA Minex 6.4Page 17 of 78Open Pit Design tutorial Merging The purpose of merging is to make sure that all grids are completely defined over the area of interest. You will need this in order to report reserves accurately. For more information about merging, see Appendix A - Merging Theory. Creating merged grids Activity: Create merged grids for weathering A dipping seam disappears where it reaches the surface. By merging grids, you force all the grids to follow the base of weathering when they reach the surface. This enables you to perform volume calculations using the grids because every grid completely covers the same area in the X and Y planes. None of the merged grids have empty spaces (that is, null values) in them that would cause errors when the software performs mathematical operations on the grids. This activity instructs you to merge grids up to the base of weathering, that is, the WSF grid. Note:An alternative technique one that you could use for gently dipping seams is to merge grids up to a TOPCOAL grid. This tutorial does not describe the TOPCOAL method. 1.Open the borehole database THEDON.B31. 2.Select OP Design > Create Merged Model. 3.Fill in the Create Merged Model form as shown. Tip:To load the seams, click Select Seams, select all the seams and click OK. Merging Activity: View the difference between a merged grid and a model grid GEOVIA Minex 6.4Page 18 of 78Open Pit Design tutorial 4.Click Ok. 5.If prompted, click Yes to overwrite the existing layers.olc file. 6.Close the Create Merged Model form. Activity: View the difference between a merged grid and a model grid 1.Open THEDON.GM3.2.Display the SW1SR grid from the Merged.grd folder. 3.Display the corresponding grid, SW1SR, from the MODEL.grd folder. MergingActivity: Show a grid for reference GEOVIA Minex 6.4Page 19 of 78Open Pit Design tutorial You can cross-section some of the merged model to look for gaps in the seams (which could indicate missing data) or spikes (which could indicate problems with merging). Activity: Show a grid for reference 1.Clear Graphics. 2.From the Merged folder, select TOPS.grid, right-click, and choose Display and Open.3.Select Mounts > Section > Create. The Section Create form appears. MergingActivity: Show a grid for reference GEOVIA Minex 6.4Page 20 of 78Open Pit Design tutorial 4.Click Digitize. 5.Drag a cross-section line across the grid, and (left) click. 6.Right-click, and click Accept. MergingActivity: Show a grid for reference GEOVIA Minex 6.4Page 21 of 78Open Pit Design tutorial 7.Fill in the form as shown, and click Ok. 8.When prompted, type 10K_xsec, as the name of the cross-section, and click Ok. 9.Close the Section Create form.10.In the Runtime tab of the Minex Explorer, expand the Mounts folder until you locate the 10K_xsec mount. 11.Right-click the 10K_xsec mount, and select Draft on Mount. 12.Select Mounts > Section > Seam Cross-Section. MergingActivity: Show a grid for reference GEOVIA Minex 6.4Page 22 of 78Open Pit Design tutorial 13.Click the Initialize tab, and fill in the form as shown. 14.On the Seams tab, set Default DD Name to Merged, and click Load Seams. 15.Click Ok. Tip:In Graphics, zoom in to view the seam cross-section in detail. MergingActivity: Show a grid for reference GEOVIA Minex 6.4Page 23 of 78Open Pit Design tutorial Now you can load some of the seams individually (to make it easier to see breaks and spikes in the seams). OP design overview GEOVIA Minex 6.4Page 24 of 78Open Pit Design tutorial OP design overview The following diagram shows the general pit design workflow. Pit boundary, bench grids, and bench list GEOVIA Minex 6.4Page 25 of 78Open Pit Design tutorial Pit boundary, bench grids, and bench list To start creating a pit, you must: create a bench list and bench grids determine a pit boundary create bench grids create a bench list Creating bench grids Note:Bench grids will have x and y extents that are the same as the TOPS grid (because you will specify the TOPS grid as the reference grid). You will create the blocks to be mined only from the parts of the benches that are within the pit after the pit is created. Activity: Create bench grids 1.Click the 3D Design tab. 2.Clear Graphics. 3.Select OP Design > Create Bench Grids. The Create Bench Grids form appears. 4.Fill in the form as shown. Note: When you specify TOPS as the reference grid, the grid extents appear in the form. Pit boundary, bench grids, and bench listActivity: Create bench grids GEOVIA Minex 6.4Page 26 of 78Open Pit Design tutorial The elevation of the lowest bench grid will be 500. The elevation of each bench will be 10 higher than the previous one. The highest bench grid will have an elevation of 730. 8.Click Generate List. The Bench Grid Setup table is populated. 9.Click Ok to create the bench grids. The Bench Grids Create Report is generated in the Output Window. Pit boundary, bench grids, and bench listActivity: Create bench grids GEOVIA Minex 6.4Page 27 of 78Open Pit Design tutorial 10.Close the Create Bench Grids form. 11.To display the bench grids, click the Project tab and drag a grid file into Graphics. The grid is displayed. Creating a bench list A bench list is a list of all the benches in the pit. By creating a bench list you save time because doing the activity on the single bench list file instead of on each bench individually. Pit boundary, bench grids, and bench listActivity: Create a bench list GEOVIA Minex 6.4Page 28 of 78Open Pit Design tutorial Activity: Create a bench list 1.Select OP Design > Bench list. 2.Fill in the form as shown. Tips:Click Fill with Grids to fill the bench list. A quick way of copying numbers between cells in the bench table is to drag the number from cell to cell. 4.Click Save. You can now use the file mybenches.bls to refer to the 24 benches, defined by grids BENCH730 to BENCH500. Pit boundary, bench grids, and bench listActivity: Create a bench list GEOVIA Minex 6.4Page 29 of 78Open Pit Design tutorial 5.Click the Preview tab to check that the slopes and berm widths of each bench appear as shown. 6.Click Ok.You have created the bench list. Benches GEOVIA Minex 6.4Page 30 of 78Open Pit Design tutorial Benches This section contains information about the workflow for creating benches and the Display Pit Data section of the Geometry Display form. When you design a pit, you will use this form frequently. You can show or hide parts of the pit, including toes or crest for benches, strips, and blocks. Benches GEOVIA Minex 6.4Page 31 of 78Open Pit Design tutorial Create benches workflow BenchesActivity: Plot geometry data GEOVIA Minex 6.4Page 32 of 78Open Pit Design tutorial Determining a pit boundary You can use Minexs Pit Optimiser module, if you have it, to determine the most-economical pit boundary and depth. If you do not have the Pit Optimiser, you can determine the pit boundary by other means. This tutorial assumes you do not have the Pit Optimiser.In this tutorial we will use a predefined polygon which we will use to digitize the toe boundary string of the bottom bench or pit floor. Activity: Plot geometry data 1.Clear Graphics. 2.Select String > Geometry Display. 3.Fill in the form as shown, and click Ok. The geometry data is displayed. BenchesActivity: Plot geometry data GEOVIA Minex 6.4Page 33 of 78Open Pit Design tutorial Note: This string will be toe of the bottom bench that you will digitize. Display Pit Data You can use the Display Pit Data section of the Geometry Display form to hide the components of a pit. This helps remove clutter from Graphics, particularly when you are working with two or more pits at the same time. You can use the Display Pit Data section to switch between showing and hiding parts of a pit. You can drag the splitter between the Geometry Data section (at the top) and the Pit Data Selection section to adjust the height of the sections.BenchesActivity: Plot geometry data GEOVIA Minex 6.4Page 34 of 78Open Pit Design tutorial The components of this form are described in the Minex Help, in the Geometry Display topic. BenchesActivity: Create benches for a pit (without a ramp) GEOVIA Minex 6.4Page 35 of 78Open Pit Design tutorial Activity: Create benches for a pit (without a ramp) If you havent created benches before, you can create a pit without a ramp before you create one with a ramp. A pit without a ramp is easier than one with a ramp, and it will help you become familiar with the forms that you use when designing a pit. You will design the pit so that the toe of the lowest bench (Bench 24) rests on the lowest seam (WGG2SF).1.Select OP Design > Pit/Dump Design. 2.Fill in the form as shown, and click Ok. 3.In Graphics, right-click, and select Whole Line from the menu. 4.Click on the line of interest. 5.In Graphics, right-click, and select Accept from the menu. 6.Select String > Geometry Display. 7.Expand the Display Pit Data section. Benches Activity: Design a pit using automatic pit projection GEOVIA Minex 6.4Page 36 of 78Open Pit Design tutorial 8.Check the defaults settings match the Display Pit Data section as shown. 9.Click Ok. 10.Close the Geometry Display form. Activity: Design a pit using automatic pit projection 1.Select OP Design > Pit/Dump Design. 2.Fill in the form as shown. Tip:Notice that the Pit/Dump text box is set to 1. You are designing pit 1. By entering a different Pit/Dump number, you can design an alternative pit. Benches Activity: Design a pit using automatic pit projection GEOVIA Minex 6.4Page 37 of 78Open Pit Design tutorial 3.Click the Advanced Options tab. 4.Check the default settings match the form as shown, and click Ok. Note:With the zero berm option on, there will not be any berms on the low wall side. For steeply-dipping deposits, this is often desirable. Benches Activity: Design a pit using automatic pit projection GEOVIA Minex 6.4Page 38 of 78Open Pit Design tutorial The pit boundary strings for the pit shell are displayed. 5.In the Geometry Display form, right-click and delete rows 1 and 2, and click Ok to display the pit boundary strings only. BenchesActivity: Add benches manually. GEOVIA Minex 6.4Page 39 of 78Open Pit Design tutorial For a more precise pit design, you can use the manual bench design method. Activity: Add benches manually. 1.Select OP Design > Pit/Dump Design. 2.Fill in the form as shown, and click Ok. BenchesActivity: Copy the pit floor into pit 2 GEOVIA Minex 6.4Page 40 of 78Open Pit Design tutorial An error message appears. You have instructed the software to project a string up to the crest of bench_24, but you have not specified what string to use. Before you created an automatic projection, you digitized a string to use as the pit floor, but that was in pit 1 whereas for the manual projection the pit is pit 2.To make this activity work, you will need to copy the pit floor used in pit 1 into pit 2. You will use the Geometry Display form to do this. Activity: Copy the pit floor into pit 2 In this exercise you will use the toe string of bench 24 from pit 1, to digitise the toe string of bench 24 for pit 2. 1.Press CTRL+D to display the Geometry Display form. 2.Show the toe of bench 24 of pit 1, and hide the other benches. BenchesActivity: Design a pit using manual pit projection GEOVIA Minex 6.4Page 41 of 78Open Pit Design tutorial 3.Select OP Design > Pit/Dump Design. 4.Fill in the form as shown, and click Ok. 5.Right-click in Graphics, and click Whole Line, and then click on the bench 24 toe string. 6.Right-click in Graphics, and click Accept. 7.Adjust the Geometry Display form to display only Pit 2. Activity: Design a pit using manual pit projection 1.Select OP Design > Pit/Dump Design. BenchesActivity: Design a pit using manual pit projection GEOVIA Minex 6.4Page 42 of 78Open Pit Design tutorial 2.Fill in the form as shown, and click Ok. 3.Fill in the form as shown, and click Ok. BenchesActivity: Design a pit using manual pit projection GEOVIA Minex 6.4Page 43 of 78Open Pit Design tutorial 4.Fill in the form as shown, and click Ok. Provided that the Geometry Display form is set to display toes and crests of bench 23 and 24 of pit 2, you will see the benches in Graphics. When you project benches in a pit that you intend to be a final pit, you should stop after each bench to smooth any unwanted kinks in the bench. This helps keep benches, strips, and blocks smooth, and reduces the chance of string and data problems later in the pit design process. 5.Continue to manually project benches until you have projected to the crest of bench 1 as shown. BenchesActivity: Design a pit using manual pit projection GEOVIA Minex 6.4Page 44 of 78Open Pit Design tutorial 6.Save the geometry file. 7.On the Geometry Display form, enter the information as shown, and click Ok. Next, you will create a grid of the pit. 8.Select OP Design > Compute Pit/Dump Surface. 9.Fill in the form as shown, and click Ok. Benches Activity: Use the Insitu Resource Report to see the volume, tonnage, and strip ratio for a pit GEOVIA Minex 6.4Page 45 of 78Open Pit Design tutorial The grid is created and is visible in the Minex Explorer. Next, you will create a triangle of the pit. 10.On the Compute Pit/Dump Surface form, select the Triangulate option, and click Ok. 11.Specify pit2 as the file name of the triangle. 12.Close the Compute Pit Surface form. 13.Clear Graphics. 14.Display the PIT2 grid, and then the triangle. Activity: Use the Insitu Resource Report to see the volume, tonnage, and strip ratio for a pit To use the Insitu Resource Report to see the volume, tonnage, and strip ratio for pit 2: 1.Select Seam Model > Insitu Resource Reporting. 2.Fill in the form as shown. Tip: Click Create List to populate the Seam table Benches Activity: Use the Insitu Resource Report to see the volume, tonnage, and strip ratio for a pit GEOVIA Minex 6.4Page 46 of 78Open Pit Design tutorial Benches Activity: Use the Insitu Resource Report to see the volume, tonnage, and strip ratio for a pit GEOVIA Minex 6.4Page 47 of 78Open Pit Design tutorial 3.Click Ok The report is generated in the Output Window. Strips GEOVIA Minex 6.4Page 48 of 78Open Pit Design tutorial Strips Create strips workflow StripsActivity: Create strips GEOVIA Minex 6.4Page 49 of 78Open Pit Design tutorial Activity: Create strips 1.Clear Graphics. 2.Open the Geometry Display from, and display Pit2, Bench 24, Toe. 3.Select OP Design > Pit/Dump Design. 4.Fill in the form as shown, and click Ok. 5.Digitize a strip from left to right using the Snap to Line digitizing option. 6.Right-click in Graphics, and choose Accept. StripsActivity: Create strips GEOVIA Minex 6.4Page 50 of 78Open Pit Design tutorial 7.Estimate how many strips you will need. You can do this by using the Query tool to find the width of the pit at bench 1 (perpendicular to the strip line) and then divide this by the intended width of the strips. In this example, the number of strips might be 1730/100 = 17. 8.Fill in the form as shown, but use the number of strips you determined in the previous step. 9.Click Ok. 10.If an error message appears One or more strips do not intersect the bench boundary. These strips have been removed, click Ok (if a strip does not intersect the bench boundary, then the strip should be removed). 11.Reopen the Geometry Display form, click Reset, enter the details to display Pit 2, Bench 24, Toes, and click Ok. The strips are displayed in Graphics. StripsActivity: Project the strips GEOVIA Minex 6.4Page 51 of 78Open Pit Design tutorial Manually adjust any strips that are outside the pit boundary. You can do this by moving points so that they follow the boundary or by digitizing the entire strip again. The following image shows a strip that is outside the pit boundary. Note:When you move a point to join it to the pit boundary, use the Snap to Line digitizing option. If you used the XY + Z option instead, the point might be located slightly within or outside the boundary. When all the strips are within the boundary you can project the strips up (from bench 24 to bench 1). Activity: Project the strips 1.Select OP Design > Pit/Dump Design. 2.Fill in the form as shown, and click Ok. StripsActivity: Project the strips GEOVIA Minex 6.4Page 52 of 78Open Pit Design tutorial The Status bar informs you that the software is projecting the strips. If you do not see strips for benches 23 and 24, make sure they are set to display in the Geometry Display form.3.Project the strips for each bench one at a time (or two at a time), correcting any errors in the strings as shown. 4.Correct any string errors by moving or editing points in the strip. 5.Save the changes to the geometry file. Next, you will create the first and the last strips and project them up. 6.Select OP Design > Pit/Dump Design. 7.Fill in the form as shown, and click Digitize. 8.When the Status bar shows the prompt to digitize the start of the strip, digitize two lines that cut across the pit boundary as shown. StripsActivity: Project the strips GEOVIA Minex 6.4Page 53 of 78Open Pit Design tutorial Tip:To make it easier to digitize the first strip, use the Geometry Display form to hide unnecessary parts of the pit. 9.Click Ok in the Pit/Dump Design form to create the first string for all the benches. The string ID for the first strip is -1. Similarly, create the last string. 10.In the Pit/Dump Design form, select the Last option. 11.Click Digitize. 12.Digitize two lines as shown. 13.Click Ok to create the last strip for all the benches. The string ID is one more than the string that was the previous last string. Next, create the strip ends. StripsActivity: Digitize a missing strip at the crest GEOVIA Minex 6.4Page 54 of 78Open Pit Design tutorial 14.Fill in the form as shown, and click Ok. Possible problems when creating strips Activity: Digitize a missing strip at the crest You might need to digitise a missing strip at the crest if a specific bench had all strips present at the toe, but is missing a strip at the crest. To check for such a problem, use the Geometry Display form to show the crests of all strips for each bench, one at a time. In the following image, the dashed line indicates where a strip is present for the toe, but not the crest. If you find this problem, you can digitize the crest of the missing strip (use the same string as the toe of the missing strip). 1.Select OP Design > Pit/Dump Design. StripsActivity: Digitize a missing strip at the crest GEOVIA Minex 6.4Page 55 of 78Open Pit Design tutorial 2.Fill in the form as shown, and click Ok. RampsActivity: Create benches for a pit (with a ramp) GEOVIA Minex 6.4Page 56 of 78Open Pit Design tutorial Ramps This section describes the same procedure as creating a preliminary pit, except that it includes adding ramps and provides more detail on how to correct some common errors. Activity: Create benches for a pit (with a ramp) For a steeply-dipping pit, you may require a ramp to allow the mining equipment to move to areas where it is needed. 1.Select OP Design > Pit/Dump Design. 2.In the Pit/Dump Design form, start creating a new pit, called Pit 5, digitizing the same toe of bench 24 that you used for the preliminary pit you created earlier. Next, create a kink in the toe of the lowest bench for the start of the ramp. 3.Show the toe of bench 24 for pit 5, and hide all the other toes and crests.4.Select a point near where you want the ramp to enter the pit floor. 5.In point mode, right-click the point, and choose Manipulate > Move > Drag XY. 6.Move the point to create a suitable entrance for the ramp. Note:You might have to move more than one point to create a suitable entrance for the ramp. 7.Select OP Design > Pit/Dump Design. RampsActivity: Create benches for a pit (with a ramp) GEOVIA Minex 6.4Page 57 of 78Open Pit Design tutorial 8.Fill in the form as shown. 9.Click the Ramps tab, select the Build Ramps box, and click Create/Edit Ramps. 10.Fill in the form as shown, and click Ok. Minex returns to the Pit/Dump Design form. 11.Click Fill Table. RampsActivity: Create benches for a pit (with a ramp) GEOVIA Minex 6.4Page 58 of 78Open Pit Design tutorial 12.Open the Geometry Display form, and make sure that ramps are selected. 13.In the Pit/Dump Design form, click the Bench & Projection Selection tab. 14.Fill in the form as shown, and click Ok. 15.Digitize two entry points on the toe of bench 24. Tip:It may help to hide all the crests and show only the toe of bench 24. You can use the Geometry Display form to do this. In the Pit/Dump Design form, the Out option is now selected. 16.Show all the toes and crests using the Geometry Display form. 17.Continue clicking Ok in the Pit/Dump Design form. Each time you click Ok, look at the message in the Pit/Dump Design form. The message will inform you which crest or toe you are projecting from and to. Look in Graphics to see the benches and ramps being created. Caution: Project benches slowly. As you do so, check for kinks in each toe and crest and smooth them by manually moving points. This helps keep benches, strips, and blocks smooth and reduces the chance of string and data problems later in the pit design process. 18.Correct unwanted spikes by selecting and moving points. RampsActivity: Correct any ramp points lost errors GEOVIA Minex 6.4Page 59 of 78Open Pit Design tutorial It is worthwhile correcting spikes in the first benches you create to avoid duplicating the spikes in subsequent benches. Activity: Correct any ramp points lost errors 1.Hide the ramp and all the toes and crests except for the last crest that was created. 2.Set the Pit/Dump Design form to project from the correct crest to the correct toe. 3.Click Ok. 4.When prompted, digitize two points on the crest. You can show all the toes, crests, and the ramp. 5.Delete the points, in the ramp, that have incorrectly extended past the last crest. 6.Continue clicking Ok in the Pit/Dump Design form to create more benches. 7.Continue to digitize benches until you have digitized all the benches up to and including bench 1. Note: You may have to manually edit some of the points on the final sections of the ramp (and the final toes and crests). RampsActivity: Correct any ramp points lost errors GEOVIA Minex 6.4Page 60 of 78Open Pit Design tutorial 8.Create a grid of the pit. Use the same procedure as you did when you created a preliminary pit. 9.Create a triangle of the pit. 10.Create an Insitu Reserves Report for the pit. Creating strips for a pit (with a ramp) You create strips, the first and last strip and the strip ends in the same way as you would for a pit that does not have a ramp. Blocks GEOVIA Minex 6.4Page 61 of 78Open Pit Design tutorial Blocks Before doing the following activity, make sure you have created benches, strips (including the first and last strip), and the strip ends. This section provides information about: the overall workflow for creating and validating blocks block creation block validation diagnostic tools and possible problems when creating blocks Blocks GEOVIA Minex 6.4Page 62 of 78Open Pit Design tutorial Creating and validating blocks workflow BlocksActivity: Create blocks GEOVIA Minex 6.4Page 63 of 78Open Pit Design tutorial Creating Blocks Activity: Create blocks 1.Make sure the benches and strips of your pit are displayed.The pit used in this activity is the pit you created earlier in the tutorial, pit 2. 2.Select OP Design > Pit/Dump Design. 3.Fill in the form as shown, and click Ok. A message appears. 4.Click OK. BlocksActivity: Create blocks GEOVIA Minex 6.4Page 64 of 78Open Pit Design tutorial 5.Digitize a line, on the left side of the pit, that is perpendicular to the strips, and accept the string. The block lines should cover the entire pit. This shows you approximately how many block lines you will need to divide the strips into blocks. Next, create the blocks lines more precisely. 6.Count the number of blocks you need, and enter it as the End number in the Pit/Dump Design form. 7.Click Ok, and digitize with the first block line close to the pit boundary.8.Fill in the form as shown, and click Ok. The blocks are generated. BlocksActivity: Create blocks GEOVIA Minex 6.4Page 65 of 78Open Pit Design tutorial 9.Show only the blocks on one of the benches, for example bench 10. 10.Zoom in to one of the blocks on bench 10. BlocksActivity: Validate blocks and fix errors GEOVIA Minex 6.4Page 66 of 78Open Pit Design tutorial Each block is marked with the block and strip number in the format /. Validating Blocks Activity: Validate blocks and fix errors This activity presents some examples of block validation errors and how to fix them. See Diagnostic Tools and Possible Problems with Blocks for more information about the different types of block validation errors and their solutions. 1.Clear Graphics. 2.Select OP Design > Pit/Dump Design. 3.Fill in the form as shown, and click Ok. BlocksActivity: Validate blocks and fix errors GEOVIA Minex 6.4Page 67 of 78Open Pit Design tutorial This will validate only bench 24. You can validate the other benches later. You might see errors such as the following. If you see the Polygon not formed error: 4.Look closely at the specific block in Graphics. The problem is that the centroid for an adjacent block is out of place. To fix the problem, you must move the centroid to the left. 5.Select the centroid and drag it into the adjacent block (on the left side). Fix any other centroid problems using the same method as described in the previous step. 6.Validate bench 24 again. BlocksActivity: Validate blocks and fix errors GEOVIA Minex 6.4Page 68 of 78Open Pit Design tutorial If you see the Layout line touches only one strip error 7.Use the Geometry Display form to show strips, blocks, and crests, but to hide benches and toes. 8.Select the line around the block a few times, and you will see that the crest of the strip curves round (for example, to the right) and overlaps the crest of the next strip. 9.Remove points on the end of the crest of the first strip so that it does not cross the second strip. 10.Regenerate strip ends for the second strip for that bench. 11.Generate the blocks again for the bench and strip that shows the problem (bench 24, strip 9 in this example). BlocksActivity: Validate blocks and fix errors GEOVIA Minex 6.4Page 69 of 78Open Pit Design tutorial 12.Validate the blocks for bench 24 again. When there are no errors you will see the message that the pit is valid (for the range of benches that you specified). In Graphics, the block number should appear in the centre of the block. 13.Fill in the form as shown, and click Ok. If all the blocks are coloured in, then the blocks are correctly formed; if a block is not coloured in, one of the strips might have crossed another strip. 14.Correct any strip problems as you did in step 6 of this activity, that is perform these steps: a.Edit the strips. b.Regenerate strip ends for that strip. c.Regenerate blocks for that strip. d.Display the blocks again. 15.Continue to validate all the benches and correct the problems that you find. BlocksActivity: Validate blocks GEOVIA Minex 6.4Page 70 of 78Open Pit Design tutorial Diagnostic tools and problems with blocks Activity: Validate blocks Sometimes due to geometry layouts, blocks may not form correctly. 1.Select OP Design > Pit/Dump Design. 2.Fill in the form as shown, and click Ok. The following image shows one block that has not formed. When you validate a bench, the blocks that have problems are marked with a black cross in Graphics, and the Output Window provides more information about the validation errors. BlocksActivity: Validate blocks GEOVIA Minex 6.4Page 71 of 78Open Pit Design tutorial Blocks Activity: Drag centroids inside their respective blocks GEOVIA Minex 6.4Page 72 of 78Open Pit Design tutorial Activity: Drag centroids inside their respective blocks The numbers inside each block are called block centroids. It is important that the centroids are inside their respective blocks. If they are not, you can drag them inside the block in question. Activity: Fix crossed strip lines The fine detail of your strips and blocks might show that some strip lines cross each other. To fix this problem, move points and digitize new points as required. Use the Snap to Line or Snap to Point digitizing options to make sure the strips join onto the pit boundary. After you have fixed the strip lines, and regenerated the blocks, check the blocks again. Activity: Fix layout lines For a block end to be formed (block ends are where the layout lines exist), and hence be an individual block, the layout line must cross both strips. It is not enough for the layout line to cross one strip and the strip end rather than the next adjacent strip.If a strip is too short to intersect a layout line, and it is important for that block to form: 1.Delete the strip end in question. 2.Extend the strip so it intersects with the layout line and goes beyond it. This will ensure that a block end is formed. 3.Regenerate your strip ends. 4.Regenerate the block. Tip:After fixing string problems, save your geometry file. Activity: Delete blocks outside the pit If Minex creates any blocks outside the pit, that should not exist, select the centroids of those unwanted blocks and delete them. Then validate the blocks for that bench again. Summary GEOVIA Minex 6.4Page 73 of 78Open Pit Design tutorial Summary Congratulations on completing this tutorial. You should now have an understanding of designing a pit in Minex. You have learnt a number of concepts and topics including: correcting holes in grids creating merged grids determining a pit boundary creating bench grids creating a bench list showing and hiding elements of a pit using the Geometry Display form creating the benches of a pit, with or without a ramp creating strips, including strip ends creating and validating blocks Appendix A: Merging theory GEOVIA Minex 6.4Page 74 of 78Open Pit Design tutorial Appendix A: Merging theory Structural modelling In any given set of structural grids modelled on a split or combined basis, you can have holes or areas of "null'' value. Such holes may represent missing data, poorer quality coal, presence of intrusions, etc.Null grid values represent a problem to both design and reserve generation for two reasons: difficulty in assigning waste material into undefined grid areas projection of pit geometry into areas of undefined grids The merging procedure provides a solution to these problems by giving undefined grids a value coincident with the overlying roof grids above them. This surface may be a base of weathering grid, topography or an overlying seam. Merging will result in all grids being defined over the entire area defined from a reference surface, usually TOPS.Merging gives rise to numerous design issues. Take the following example of seams merged up to topography. In this case, merging upwards has failed and resulted in an incorrect reporting of coal tonnage. The responsibility falls on the geologist to take the following approach when generating structural grids:Avoid masking ST to null, instead mask unwanted areas to 0 thickness, keeping the roof and floor defined. Where nulls in the floor occur, use SR and ST to create a coincident floor grid, and vice versa for roof nulls. Merging in Minex The reporting of materials, layer assignment and accumulated strip ratio is influenced by the merging practice used by the engineer. In most cases, geologists provide structural grids resolved along the crop line by setting the poor quality material to null. This leaves an irregular grid boundary and insufficient extent for design purposes. The merging procedure will overcome this problem by using TOPS (generally) as a reference surface to which all grids in the layer list will be transformed in origin, extent, and mesh size. TOPS should, therefore, be of a mesh size and extent that will give a good representation and relief to seam grids when merged. Appendix A: Merging theory GEOVIA Minex 6.4Page 75 of 78Open Pit Design tutorial The following series of images represent the common merging methods: Assignment of stratigraphic layers to Base of Weathering grid (BOW) You must perform a detailed examination of the resultant model through cross sections, total coal thickness, as well as the insitu reserves before and after merging. Insitu reserve tonnages should remain almost identical as should total coal thicknessInsitu reserves generation uses the ST grids not yet present in the merged model (GRDFILE). To generate these, use the Seam Model > Seam Model Operations > Arithmetic operation. Appendix A: Merging theory GEOVIA Minex 6.4Page 76 of 78Open Pit Design tutorial Reserve generation requires all structural grids to be assigned and continuous - free from nulls. Assignment of stratigraphic layers to topography (TOPS) A top of coal grid can be generated using the Seam Model > Seam Model Operations > Upper Lower Surface operation. Assignment of stratigraphic layers to Top of Coal grid (TOPCOAL) Using Top of Coal and Weathering Grid (whichever is the minimum).Appendix A: Merging theory GEOVIA Minex 6.4Page 77 of 78Open Pit Design tutorial Assignment of Stratigraphic Layers to Top of Coal Grid (TOPCOAL) Merging must be undertaken uniquely for each group. Top of Coal (TOPCOAL) for each seam group. Bottom seam in group is merged to TOPS in this case. Appendix A: Merging theory GEOVIA Minex 6.4Page 78 of 78Open Pit Design tutorial In this example, interburdens include OB material where no overlying seams exist. Top of Coal (TOPCOAL) for each seam group and Base of Weathering Waste allocation - naming convention Seams are always merged to the seam stratigraphically above. A merged split model (B seam generalises split arrangement)