GEMS62_PitDesign

Pit and Dump DesignVersion 6.2 January 2009 Gemcom Software International Inc. 1066 West Hastings Street, Suite 1100 Vancouver, BC Canada V6E 3X1 Tel +1 604.684.6550 Fax +1 604.684.3541 www.gemcomsupport.com Copyright © 2009 Gemcom Software International Inc. All Rights Reserved. This publication, or parts thereof, may not be reproduced in any form, by any method, in whole or in part, for any purpose. Gemcom Software International Inc. makes no warranty, either expressed or implied, including but not limited to implied warranties of merchantability or fitness for a particular purpose, regarding these materials. In no event shall Gemcom Software International Inc. be liable to anyone for special, collateral, incidental, or consequential damages in connection with or arising out of the use of these materials. The sole and exclusive liability to Gemcom Software International Inc., regardless of the form of action, shall not exceed the purchase price of the materials described herein. Gemcom Software International Inc. reserves the right to revise and improve its products as it deems appropriate. This publication describes the state of this product at the time of publication for the version number stated, and may not reflect the product at all times in the future. Gemcom Software International Inc. Suite 1100 – 1066 West Hastings Street Tel: +1 604.684.6550 Vancouver, BC Canada V6E 3X1 Fax: +1 604.684.3541 Web site: www.gemcomsupport.com Gemcom, the Gemcom logo, combinations thereof, and GEMS are trademarks of Gemcom Software International Inc. Table of Contents Course Overview ........................................................................................................................ 5  Course Structure Flow Diagram ............................................................................................................... 6  Introduction................................................................................................................................. 8  Pit Design Components ............................................................................................................. 9  Pit and Dumps Node in the Project View Area ......................................................................................... 9  Pits/Dumps Design Menu ......................................................................................................................... 9  Custom Menu ......................................................................................................................................... 10  Toolbar.................................................................................................................................................... 10  Pit or Dump? ........................................................................................................................................... 10  Pit Design Theory in a Nutshell ............................................................................................... 11  Pit Slopes Terminology........................................................................................................................... 11  Pit Slope Angle .................................................................................................................................... 12  Ramps and Ramp Access ................................................................................................................... 12  Switchbacks ......................................................................................................................................... 12  Slots ..................................................................................................................................................... 13  Use of Whittle Shells in Pit Design ......................................................................................... 14  Creating Surfaces from Whittle Pit Shells .............................................................................................. 14  Prerequisites for Pit/Dump Design ......................................................................................... 16  Creating Workspaces for Pit Design ...................................................................................................... 16  Linking Pit Design Workspaces .............................................................................................................. 17  Creating Benches (Plan Views) .............................................................................................................. 18  New Pit or Dump Creation ....................................................................................................... 21  Creating a New Pit/Dump ....................................................................................................................... 21  Designing a Simple Pit ........................................................................................................................... 24  Bottom-up or Top-down Design? ......................................................................................................... 24  How Many Benches? ........................................................................................................................... 24  Designing the First Bench – A Toe with a Ramp Entrance .................................................................... 25  Next Benches ......................................................................................................................................... 27  Creating a Surface from Pit Designs ...................................................................................... 29  Create a pit surface ................................................................................................................................ 29  Combine the pit surface with topography ............................................................................................... 29  Surface Creation Errors .......................................................................................................................... 30  Typical Pit Design Issues ........................................................................................................ 32  Fillet Problems ........................................................................................................................................ 32  Crossing Line Segments ........................................................................................................................ 32  Lines that Don’t Project (“My line doesn’t project”)................................................................................. 32  Pit Design Symbols .................................................................................................................. 33  Advanced Pit Design ................................................................................................................ 34  Single Pit Splitting into Multiple Pits ....................................................................................................... 34  Example: Pit with No ramps................................................................................................................. 34  Example: Pit with Ramps ..................................................................................................................... 34  Variable Pit Slopes ................................................................................................................................. 36  Pit Slopes: Pit Slope Angle, Berm Width, and Batter Angle ................................................................ 36  Defining Geotechnical Domains .......................................................................................................... 36  Page 3 of 47 Table of Contents Blending? ............................................................................................................................................. 39  Defining Slope Domains for Your Pit ................................................................................................... 39  Multi-Benching ........................................................................................................................................ 40  Adding Ramps, Slots, and Switchbacks ................................................................................................. 41  Ramps.................................................................................................................................................. 41  Slots ..................................................................................................................................................... 43  Switchbacks ......................................................................................................................................... 45  Page 4 of 47 ramps. and dumps. pit slope angle. and grades reported by bench. switchbacks. Page 5 of 47 . and batter angle to pit designs. Additionally volumetric calculations of ore and concentrate stockpiles within these designs will be investigated. tonnages. Such activities include designing pits. crests. rock type. • Obtain volumes. Expected Outcomes Upon completion of this course. Course Prerequisites Before taking this course. you require the following: • Successful completion of GEMS Foundation course. you will be able to accomplish the following: • Assign design parameters such as berm width. and grade range from the pit design. and slots. ramps. • Knowledge of CAD tools. • Create a surface triangulation from the pit design.Course Overview The Gemcom GEMS Pit Design course is a two-day course designed for mine engineers who design and manage pit designs. • Create final pit designs complete with toes. • Knowledge of polyline concepts. Course Overview Course Structure Flow Diagram Course Structure Flow Diagram Concepts Topics Day 1 Morning Getting Started Objects definitions Capability GEMS Polylines Advance GEMS polyline tools Pit Design Project Set Up Create pit design project workspaces Create/modify status line types Create/modify bench profiles Pit Design Parameters General design parameters Define bench parameters Define ramp slot parameters Define rock code parameters Afternoon Design Set current bench/toe Create new toe/crest lines Point domain value Automatically fix features Activate feature Design (cont’d) Create ramp entrance Expand single bench Expand multiple benches Day 2 Morning Review Design (cont’d) Create slot entrance Create Switchback Design (cont’d) Create line for opposite ramping Complete design Afternoon Creating TIN Surface Create TIN surface Merge pit design with topography Calculating and Categorising Volumes Volumetric settings Volume between two surfaces Volume by bench Grades and tonnages Page 6 of 47 . Course Overview Course Structure Flow Diagram Concepts Topics Creating Dumps General dump design parameters Define bench parameters Set current bench/toe Create new toe/crest lines Create ramp entrance Expand single bench Expand multiple benches Page 7 of 47 . and as a result. Insert a ramp entrance. Smooth the new toe line before projecting again. and these can be saved together as a new design. Volumes are calculated between surfaces. 5. The design is combined with a topography triangulation. The user must change the line type of a digitised slot line to the chosen “slot” line-type profile. Pit design uses two workspaces. Once the design is complete. This manual covers the following topics: • Pit Design Components • Pit Design Theory in a Nutshell • Use of Whittle Shells in Pit Design • Prerequisites for Pit/Dump Design • New Pit or Dump Creation • Creating a Surface from Pit Designs • Pit Design Symbols • Advanced Pit Design • Single to Multi Pit Designs • Variable Pit SlopesW • Multi-Benching Page 8 of 47 . 7. you will use the tools in the Polyline menu extensively during the creation of a pit design. one for holding the lines that belong to a particular design. The user may load multiple pits and alternate between which is being designed by selecting one as the active design. the ramp entrance also requires some editing. Create a design line. 9. and the other containing all the design parameters for any number of pit designs that are stored in that workspace. Once these are created the pit designer may begin using a practical design toolbar to design their pits.Introduction The Pit Design Module enables the engineer to quickly design multiple pits. This will allow the user to digitise a toe line (if step 1 was a crest of a bench. the pit design is triangulated (creation of a surface). In GEMS. Multiple designs can be loaded into memory simultaneously. 10. use the Project View Area to access as well as organise the designs into different folders. Smooth the toe line to resemble a realistic outline. Project lines up (down if the active line is a crest) to the next bench. Select the current bench and set it as then bench toe 2. 8. Check the projection for any errors. The following describes a typical workflow: The following describes a typical workflow: 1. Pit Design is based on polylines. 4. The module uses workspaces to store the pit design parameters and design lines. it would create a crest line. Usually. 3. 6. • Activate Feature: Define the line from which you are using to project. • Managing pit designs through folder structures.Pit Design Components The following section describes the pit design components. You can access the Pit/Dumps Design from the Tools menu as show in the image to the right. saving. • Opening. removing the need to define the properties for each design Pits/Dumps Design Menu The Pits/Dumps Design menu contains all of the design commands. and closing pit designs. • Create New Toe/Crest/Slot Line. Folders allow pit designs to be grouped. Page 9 of 47 . Pit and Dumps Node in the Project View Area The Pit and dumps node in the Project View Area controls the following: • Selecting a workspace. • Copying pit designs. All of these commands can also be found on the pits/dump design toolbar. • Expand Single/Multiple Bench(es): Project the toe/crest line up/down. • Delete Features Above/Below Active: Allows you to delete all lines below or above the active bench. Some of the more essential features in the menu are: • Set Current Bench (Crest/Toe): Define the bench you are designing. Follow these steps to modify the display properties. 1. and a pit does the reverse. which helps improve your efficiency when working on pit designs. In the Project View Area. right-click on Pit and dumps. The pit design toolbar has the following buttons: Button Name Button Name Set current bench (Crest) Create switchback Set current bench (Toe) Create line for opposite ramping Create new design line Expand one bench Check slope angle Expand multiple benches Fix feature Delete features below active Activate feature Delete features above active Create ramp entrance Transform to Inclined Sections Create slot entrance Pit or Dump? The only difference between a pit and dump is that a dump projects outwards from a crest and inward from a toe. Toolbar The pit design application features a toolbar that can be activated by right-clicking on the Pit and dumps node in the Project View Area. Page 10 of 47 . In the Pit Environment Properties. click any of the display options to enable them. and choose Properties. 2.Pit Design Components Custom Menu Custom Menu GEMS provides a custom Pit Design menu that combines elements from the Polyline menu. To access the menu. choose Options > Toolbar > Custom Menu > Pit Design. ramp widths.Pit Design Theory in a Nutshell Before you can proceed further in this module. and three small pits merging into one large pit. you need to understand some principles explained in this chapter. The following diagram is a GEMS pit design that uses various pit slopes. Pit Slopes Terminology The figure below explains how pit slopes are used within GEMS. Page 11 of 47 . The ramps from the small pit were designed in such a way that they merged into a larger ramp. GEMS can deal with various slope angles and ‘blend’ one angle to the next while it is projecting a bench. although this may not be obvious from the images. Ramps may also need access to berms so equipment (such as drills) can move throughout the pit without resorting to temporary ramps. and are laterally extensive. It is quite evident from the diagram that each form of access will have a negative impact on overall pit slope angle. Page 12 of 47 . faults. Care must also be taken that there is room for maneuvering the trucks. Slope stability is primarily compromised by weak rock. and as such more waste will be mined. GEMS can provide ramp access at the bench toe. The following diagram explains how ramps can access bench toes and crests. The version on the right cuts significantly less waste. and when designing ramps the turning radii of trucks must be taken into account. This allows the designer to give access to ore without cutting too much waste. and slip planes (rock or soil that allows overlying material to slide more easily). Geotechnical engineers provide the long-term planner or mine designer with models for adjusting the pit design to the geotechnical ground conditions. because of their limited access for blasting (creating slots is costly and difficult). or both automatically. Placing of ramps is integral as a ramp will reduce the overall slope angle. Also. Slots are not very flexible. The following figure shows an example of gaining access to a small orebody (left through a ramp. This method does cut more waste. Switchbacks Slots are effectively ramps. they also may be difficult to fit on the property. and as such will drop the value of the pit as well. right through a slot). be aware that joining multiple ramps can produce a safety hazard. but they do not follow the shape of the pit.Pit Design Theory in a Nutshell Pit Slopes Terminology Pit Slope Angle Pit slope is determined by rock competency and the resulting slope stability. However. slots are generally avoided if possible. or the crest. or by geotechnical features such as joint sets. Because they move away from the pit. Ramps and Ramp Access Ramps are roadways that allow trucks to get to various sections of the pit. which in turn reduces the value of the pit. although this may not be apparent from the pictures. Because they move away from the pit. because of their limited access for blasting (in other words. The following figure shows an example of gaining access to a small orebody (left through a ramp. but they do not follow the shape of the pit. creating slots is costly and difficult). However.Pit Design Theory in a Nutshell Pit Slopes Terminology Slots Slots are effectively ramps. right through a slot). Page 13 of 47 . slots are generally avoided if possible. and are laterally extensive. they may be difficult to fit on the lease property. The version on the right cuts significantly less waste. This allows the designer to give access to ore without cutting too much waste. Slots are also not very flexible. select the SEG you want to convert. If you would like to eliminate the process of later converting your SEGs into surfaces. fill-in any additional information. In SEG. a. identify your. continue to the following steps. Select the options for Folder and Attribute. b. c. and click OK. 5. Although the SEG can be used for displaying. In the Import from Whittle dialog box. Click Import. 4. In the popup Triangulation Properties dialog box. 6. give the triangulation a name. it is easier to get a useful display for pit design using a surface triangulation.par files. display the Whittle shell while designing. Page 14 of 47 . Choose Block > Utils > Create Surface from SEG to open the Create Surface from SEG dialog box. To create a surface from a SEG.res and . and identify the elevation model and the block model project where you willl be storing the shells. Creating Surfaces from Whittle Pit Shells To bring in information from Whittle use the following method. and click OK. Select File > Classic Import > Pits from Whittle. 3. be certain to select the Auto-create surfaces from selected pits option.Use of Whittle Shells in Pit Design To ensure that you are using the optimal pit shape that Whittle calculated for the pit design. Select which pit shells you would like to import. and select Save. Page 15 of 47 . right-click the triangulations workspace icon in the Project View Area.Use of Whittle Shells in Pit Design Creating Surfaces from Whittle Pit Shells To save the workspace. ramp widths. subtype Pit/Dump design – This workspace stores all the design lines. etc. Select Pit and dump design. Select Set up a group of workspaces in one step.Prerequisites for Pit/Dump Design You need to set up the following items before you can use pit/dump design in GEMS (for further details. 4. Choose Workspace > New to open the Workspace Wizard. In addition to setting up these items. • Polyline workspace (subtype Pit/Dump Design). • Pit/Dump Design workspace – This workspace stores all the parameters that go with the designs (slope angles. ramp gradients. Creating Workspaces for Pit Design Pit design in GEMS needs two types of workspaces: • Polyline workspace. 2.). • Plan views for design. • Link the Pit/Dump Design workspace to the Polyline (subtype Pit/Dump Design) workspace. • Create and open a Pit/Dump Design from the Project View Area. please refer to latter sections of this manual) : • Line types and corresponding line display profiles for the following lines: ♦ TOE (normally RED) ♦ CREST (normally GREEN) ♦ SLOT (normally LIGHT BLUE) ♦ RAMP (normally CYAN) • Pit/Dump Design workspace. 3. Choose Workspaces > Create or Modify Workspace to open the Structure Editor. Page 16 of 47 . you need to complete the following actions: • Add the Pit/Dump Design workspace to the Project View Area. You can create the two workspaces in one step. and click Next. 1. and click Next. Note: The Pit Design menu (Tools > Pits/Dumps Design) will not be activated until you have set up and completed the required actions for the workspaces. Linking Pit Design Workspaces Before you can create pit designs in the pit design workspace. Linking the workspaces ensures that all the pit design lines are stored in a single polyline workspace. Add the Pit and dump design workspace to the Project View Area: a. and click Open. follow these steps. click Finish. Once the workspaces are created. and click Select. Page 17 of 47 . 2. To create the workspaces. right-click the Pit and dump design workspace. 1. Right-click the Pit and dumps node and select Add Workspace to open the Select Workspace dialog box. In the Project View Area. Select a workspace to add. you need to link your polyline and your pit design workspaces together. b. Edit the names and descriptions of the workspaces and click Next. 6. close the Structure Editor. To link the two workspaces.Prerequisites for Pit/Dump Design Linking Pit Design Workspaces 5. Page 18 of 47 . to browse to the polylines workspace where you want to store all of the design lines you create. If it does. GEMS will give a warning that there are no records in the workspace. Click Properties.Prerequisites for Pit/Dump Design Creating Benches (Plan Views) Note: If you don’t select ALL records when opening the workspace. New Profile. Click OK. Under the Volume Calculations section enter in a unique number for this series of views. right-click the Pit and dump design workspace again. Creating Benches (Plan Views) In GEMS. In the Project View Area. Notice that the quick-menu has changed and shows more options. then you must create them. click 3. 1. follow these steps. give the profile a name. The elevations for toe and crest are also calculated from the definition. If plan views for the benches have not been defined. 2. To create a new profile. refer to the GEMS Foundation Manual. upper and lower elevations. Click Browse. 5. Note that for pit design the thickness of a plan (the difference between the upper and lower limits) will be used as the bench height. 4. Enter values for the reference. and click OK. To create a plan view. bench height is controlled by the plan view definition. 3. For more information on plan views. open the workspace with ALL records. This should not prevent you going to the next step. Select View > Plan View > Define Plan Views to open the Plan View Editor dialog box. click the Profiles tab and expand the Plan Views folder. 7. In the Parallel Section Creation dialog box. Repeat steps 2 to 4 to add more profiles. and click OK.Prerequisites for Pit/Dump Design Creating Benches (Plan Views) 4. 5. enter the values as needed to generate the plan views. Click Apply. 10. When you are prompted to generate parallel plan views. and choose Set Active. To create a series of plan views which are parallel to the view that was created. In the Project View Area. You will also need to expand the different series to find your desired plan view. Right-click the new plan view. 8. 6. Page 19 of 47 . click Yes. select View > Create Sections > Parallel Sections. 9. Creating Benches (Plan Views) When complete.Prerequisites for Pit/Dump Design 11. Page 20 of 47 . crest (near end) or middle.e. Place Reference Plane allows you to set the reference elevation at either the toe (far end). You can set any of these planes as the “active section”. UP if you are in a plan view). Note: A positive spacing for plan views will automatically create sections that are below the original.. It will be located under its series number. To create sections towards your view (i. enter a negative value for Spacing Between Sections. your list of plan views can be found in the Profile tab of the Project View. follow these steps. right-click the Pit and dump design workspace. the third parameter is calculated. Only two of the three pit design parameters can be entered. 1. Choose one of the three options: Page 21 of 47 . Any parameters defined under the Pit Slopes section of the form will override these parameters. ♦ In the Options section. Click Next to advance to the Benches dialog box. and Batter angle. In the Project View Area. ♦ In the Defaults section. 2. select the parameters you want to enter for your pit design. In the General dialog box. define the default Berm width. Pit Slope. The defaults are starting angles that can be refined in the second panel. ♦ 3. From the Bench Definition Information list. make sure that all types of lines have associated line types. complete the following: ♦ Define the Name of the pit/dump.New Pit or Dump Creation Creating a New Pit/Dump To create a new pit/dump. and click New Pit/Dump. define the pit slope parameters. ♦ In the Line Types section. If you haven’t already created these line types you will need to exit the wizard and create line type profiles by choosing the menu option Format > Line Types. In the Pit Slopes section. 4. Details on these options will be covered in the Advanced Pit Design Section of this manual. define whether you are designing a Pit or a Dump. but can only be used if there are no berms on the bench. The following are explanations for some terms: ♦ Bench Height: This value is taken from the plan view definition’s thickness. The latter options are provided to save calculation time. 6. In the Select Plan Views dialog box. ♦ Calc Method: GEMS can calculate both crests and toes when it is projecting. plan views) that will be used in the pit design. then right-click on the column header to autofill all rows within that value. You should always add your benches after selecting your bench definition method. Under normal circumstances (and with current computer speeds).. click Add Benches. You can make changes to both of the non-calculated variables. as the calculated parameter will not be adjusted if you switch methods. ♦ Ramp Access: The ramp access in this dialog box overrides any ramp access information specified in the Ramp/Slot dialog box (next screen). select one or more plan views. If you want to fill a column with all of the same values. or only crest or only toe. enter the desired value in the column’s first row. Crest & Toe should be used. The calculated value will then automatically adjust. Creating a New Pit/Dump Enter Batter Angle and Berm Width: Pit Slope Angle is calculated Enter Pit Slope Angle and Berm Width: Batter Angle is calculated Enter Pit Slope Angle and Batter Angle: Berm Width is calculated To add the benches (i. This value cannot be changed without changing the plane profile. The values for each bench will be entered automatically based on the default pit design parameters you entered on the previous panel.New Pit or Dump Creation ♦ ♦ ♦ 5. Page 22 of 47 . and click OK.e. This parameter is overridden by the bench definition in the previous panel. ♦ Bottom access: Whether this ramp should have bottom access (i. Top access: Whether this ramp should have top access (i. It is recommended to use the ramp width in the name. Click Finish. • Start width: This is the width of the ramp starts with on the toe (ramping up) or crest (ramping down)..e. • Grade: This is the gradient of the ramp in percent (%). crest access).e. toe access)? This parameter is overridden by the bench definition in the previous panel. Click Next to advance to the Ramp/Slot dialog box. • Type: Select Slot or Ramp. Refer to the Ramp Access section of the manual for details.New Pit or Dump Creation Creating a New Pit/Dump 7. This name will help if you use multiple ramps in your pit design. 8. Refer to the Ramp Access section of the manual for details. or to use the ramp nomenclature that is applied at the mine. Page 23 of 47 . • Description: Use this to add any additional details. • End width: This is the width of the ramp at the crest (ramping up) or toe (ramping down).. • 9. Specify the following parameters for each ramp or slot: • Name: Choose a meaningful name. when you start at the bottom. and start designing downwards with adjustments for your ramp access. Before performing your first GEMS pit design.New Pit or Dump Creation Designing a Simple Pit Designing a Simple Pit Pit design is an art which requires experience and common sense. This will allow you to adjust the design as you go up. you need to start at the top. Some ideas for creating a smaller footprint at the bottom of the pit design are: • Different mining method for the last narrow part of the pit. do not ordinarily meet specific mining restrictions and are often too narrow at the bottom for equipment. • Turning radii for the equipment and ramp entrance size at pit bottom. The design engineer will be responsible for deciding what is the deepest. practical access may render the bench unviable. • Necessity of ramp access at the pit bottom. 3. Usually. Consider any cut made into the pit bottom wall will have a significant impact on the stripping ratio for that bench (because it is so small). Start at the bottom to ensure a proper pit shape. As a result. How Many Benches? This may seem like a simple question. This means you do not have many options as to where the ramp(s) can finish. however. Page 24 of 47 . mine-able bench based on equipment and geotechnical constraints. This means that the lowest bench cannot necessarily be mined. However. this section will discuss the following questions: • How do you make sure that you follow the optimal pit shell provided by Whittle? • How do you decide where your ramps need to start? • How do you decide where your ramps need to end? • How do you get your ramps to fit between start and end? • How do you make sure your pit design fits the geotechnical constraints? • How many benches are necessary? Bottom-up or Top-down Design? Pit design tries to answer to the following questions: To make sure that you follow your optimal pit shell shape. Re-iterate this process until the pit design is stable and well worked-out. you don’t know where the ramp entry is going to be. delete all the lines below the top. There are two things you need to consider: • What will be the first (deepest) bench? • What will be the top bench? First (Deepest) Bench To decide the first bench users will often look to the lowest elevation of their ultimate pit shell. 2. To make sure the ramp is in the correct place. you need to start with a minimally-sized outline at the bottom of the pit. but it’s one that most people get wrong on their first design. This creates a circular problem that can be resolved through iteration: 1. This will also ensure that you do not cut too much waste. Once the pit meets the topography. • Equipment to be used and/or the possibility of smaller equipment in order to realize smaller ramp diameters. Pit shells. you are limited in the choice of access. Open the Custom Pit Design Toolbar (Options > Toolbar > Custom Menu > Pit Design).New Pit or Dump Creation Designing the First Bench – A Toe with a Ramp Entrance Top Bench To determine the uppermost bench of a pit design. Load a pit shell surface in the graphics area by dragging the workspace into the graphical area of GEMS. follow these steps. Make sure that Draw triangulations as triangulations for Solid Display Overrides is selected. 4. The designer must make sure the pit design reaches above the topography in all areas of the pit.and lower-most benches. 2. The following picture illustrates this idea: Areas of the final pit design that are above the topography can be clipped at a later stage. starting at the pit bottom. Page 25 of 47 . To create the first bench. you must refer to their original topographic surface. Open a pit design by dragging a pit from your project view onto the graphical area. 1. Designing the First Bench – A Toe with a Ramp Entrance Once you choose the methodology and identify the upper. a pit design often requires more benches at the top of the pit than it would appear at first glance. 3. Due to the undulating character of most terrains. Select the first bench. you can being the design. You should see all material on the bench in 2D. 5. the corresponding triangulation data will be displayed. Insert a ramp entrance ( Create Ramp Entrance) at this point. you should note that any lines you create will be located at the plan view’s lower elevation -. select a plan view to act as your lowest bench. 10. and click on the vertices that you want to fillet. 7.not the reference elevation. Next Benches Click Set Current Bench (Toe) icon. 9. Page 26 of 47 . Note: Because you are designing the Toe. and Note: Do NOT use the normal Polyline > Create > Contour Line command. From the list. icon. To smooth the line. and click OK. 8. click Zoom to Extents to get it back. use Polyline > Vertex > Fillet. and then choose a direction and an entrance radius. As such when you “set the current bench…”. From the Plan View dialog box.New Pit or Dump Creation 6. select a ramp style. Choose Tools > Pits/Dumps Design > Create Toe/Crest/Slot Line or select the digitise the toe line. If the data disappears. Locate (or create) a kink in the toeline as a starting point to insert a ramp. New Pit or Dump Creation Next Benches Next Benches To add benches. to delete an existing vertex ♦ Vertex > Fillet. click the Expand One Bench icon. To project the bench up to the next level. Page 27 of 47 . choose the following commands from the Polyline menu: ♦ Line > Delete Segment. You will notice that the plan view jumps after the expansion. 1. 3. to add onto an existing line ♦ Vertex > 2D Move. to move a vertex along the current plane ♦ Vertex > Delete. Expand the design by one or multiple benches Repeat steps 1 to 4 until you have expanded up to the top bench. follow these steps. the design will look similar to the following: 2. To adjust the design to match the Whittle pit. to smooth a sharp edge 4. 5. In 3D. to eliminate part of a line ♦ Vertex > Insert. Choose Select View > Set Large Projection to the whole design. Next Benches Save the pit design. The resulting pit should look similar to the following: Page 28 of 47 .New Pit or Dump Creation 6. ) that are open. 1. Open the topography surface. If there are no errors.. 5. You can use the spacebar to call a list of active surfaces. Combine the pit surface with topography To combine the pit surface with topography. Open your pit. Create a surface from active data (Surface > Create > Create Surface from Active Data). 2. Validate the surface (Surface > Utils > Check for Errors). points. • Exporting to Whittle to check the impact of the engineering design on the NPV due to the introduction of ramps. including the following: • Visual checking of the design • Limiting surface for planning purposes (Cut Evaluation) • Limiting surface for reserve calculations • Updating the block model. 4. Check the resulting surface for errors. and that the triangulation edges are forced. follow these steps. drillholes. If there are no errors. 3. 3. Tip: 4. loss of net present value due to the introduction of ramps. and close any additional objects (i. etc. It should look similar to the following: Page 29 of 47 . click on the topo first and the pit second).. save the surface to the triangulation workspace.Creating a Surface from Pit Designs Creating a surface of the pit design serves several purposes. 1. 2. select the topography as the top surface and the pit as the bottom surface (i. Create a minimum of two surfaces (Surface > Intersect > Minimum of 2 Surfaces). save it to the workspace.e. If you have any errors. etc.e. This is useful when it is difficult to physically click on the surface you want. follow these steps. Note: Make sure you check the surface for crossing errors. see the following section on Surface Creation Errors for information on how to resolve them. or exporting to Whittle for checking the impact of the engineering design. Open the pit surface. Create a pit surface To create a pit surface. Create a triangulations workspace for storing the mine design. etc. and select the right surface from the list. it will be held in the specified workspace and can be accessed at any time in the future. Caution: Do NOT create a pit surface without forcing edges because the benches will not be properly represented. Page 30 of 47 .Creating a Surface from Pit Designs Surface Creation Errors Surface Creation Errors If the surface creation process finds crossing edges or duplicate nodes (due to small errors in the pit design projection algorithms). validating the surface will describe the errors as shown in the following image: To resolve the errors. follow these steps. 1. GEMS can save the outlines of any errors as either polylines or triangulations. Using this surface for reserving will lead to volume and tonnage errors. If you decide to save the outline. If you choose to Cancel in the Solid Verification Options box. Once the lines are fixed. and click one of the “bad” vertices) instead. Be careful with this option as the move you make will not affect the polylines. 4. so you won’t be able to replicate this change in the future. Page 31 of 47 . 3.” you may choose to simply delete a surface vertex (choose Surface > Utils > Delete Surface Vertex. you can create another surface. Once the location with the problem is identified you should use the Polyline tools to correct the polylines that are causing the error. After the change has been made. Alternatively.Creating a Surface from Pit Designs Surface Creation Errors 2. the area with the error will still be highlighted with a cyan outline and purple fill until the View > Redraw Picture option is selected. if there is only one “bad triangle. check the new surface for errors. Tools > Pits/Dumps Another reason lines may not project is that you have not activated the line. Since polyline workspaces for pit design are not listed in the polyline node. Page 32 of 47 . Crossing Line Segments When lines cross over themselves a cross surrounded by a circle will show up on the design. Filleting will not delete any points. Lines that Don’t Project (“My line doesn’t project”) One reason this happens is because you may have used the Polyline menu to create the pit design line. These crossovers need to be removed manually to prevent self-intersecting pit designs. Fillet Problems The following types of error messages are normally due to the fact that there are points too close to the point you are trying to fillet.Typical Pit Design Issues This section summarises pit design issues you may encounter. This is the main reason why you should always use Design > Create New Toe/Crest/Slot Line. it is easy to save the line to the wrong workspace. Use Tools > Pits/Dumps Design > Activate Feature and click the feature to make sure that the correct line is projecting. Diamond A diamond signifies a problem with a ramp or a slot. Triangle A triangle represents a very sharp bend in the polyline at the highlighted node. These errors usually occur when there is a bend in the active feature polyline that could not be corrected automatically by the program or when there was a jagged edge left in the last bench. The polyline intersects itself at the highlighted node. Quartered Circles A quartered circle indicates an error with the polyline. It is recommended that any jagged polylines be corrected before expanding to the next bench. this is a warning that the condition may lead to problems in the next expansion. A ramp or slot will be or already has been created from this node. Although not an actual error.Pit Design Symbols If GEMS detects any issues. Errors occur if a slot centreline is too short or if a centreline could not be found for the slot node. This type of error must be repaired before you can proceed. A diamond can also be a warning that the ramp gradient could not be maintained. Page 33 of 47 . the following symbols show during pit design. Name Description Cross A cross signifies that the node represents a ramp or slot node. Repeat steps 1 to 4 for the second pit. Example: Pit with Ramps It’s not easy to design on a ramp system for multiple pits that blend into each other at a higher elevation. Repeat steps 4a to 4c with the third toe line e. Use Polyline > Line > Delete Segment to break a line open. ignore ramps. follow these steps. d. Determine how many benches you have to go up before the pits merge. a. 4. Use the 2D grid to make an educated guess where the ramp will be inserted.Advanced Pit Design The following section provides advanced information for pit design. 5. Combine the toes of all three pits into one toe line. c. 4. Do this for two toe lines. 5. and project from here. The first example starts with no ramps. b. Start at the bottom of the second pit and repeat steps 1 and 2. 2. Use Polyline > Multiline > Join to join two lines together. Page 34 of 47 . 2. For this example. Start with one pit as if you are designing only one pit. Do the design for the couple of benches and see where the ramp ends. Re-do if required. Use Polyline > Line > Close to close the new line. Calculate the length of ramp you need. 3. The second example has ramps. The following instructs on how to deal with such a situation: 1. Example: Pit with No ramps To blend multiple pits into one without ramps. 3. Activate the new toe line . 1. Single Pit Splitting into Multiple Pits The following examples demonstrate how you blend multiple pits into one. Smooth the toe line to make sure the walls are safe and to make sure the equipment can move from pit to pit. Expand the pit until you have reached the bench where the wall between the two pits becomes too narrow to sustain itself. In principle. so the flat would not be so large. on the west side. The ramps are on an 8% gradient. which means that each bench of 12m will take 150m of ramp. The pit at the bottom has a circumference of 458m. and less waste could be cut. though. Then see what it looks like three benches up. with a switchback. Therefore. In 3D. The switchback introduces a wider ramp to accommodate bigger equipment. To accommodate truck access to the North pit. this design would be workable. the bottom pit needs to go up four benches and the top one three benches before the pits will merge. To accommodate 600m. Page 35 of 47 .Advanced Pit Design Single Pit Splitting into Multiple Pits In the following example. it will go around almost three times. the ramp needs to go around once fully. The length of the toe line of the pit at the top is 485m. It is evident from this view that South ramp should ideally come up a 150m further to the North. the design looks similar to the following image. and have one length of ramp added. a flat has been introduced. The following image shows that the two pits have merged. the ramp should end at the south end. When the ramp projects three benches. Advanced Pit Design Variable Pit Slopes Variable Pit Slopes GEMS can deal with various pit slope domains by using either 3D rings or geological solids which indicate regions of the pit with known geotechnical properties GEMS uses the rock code of a 3D ring or a solid to apply a specific slope. Defining Geotechnical Domains Defining geotechnical domains is not usually part of the strategic planner or mine designer’s job. Berm Width. In GEMS’ Pit Design module. • If the berm width and pit slope are specified. Nevertheless. then the berm width is calculated. • If the batter angle and berm width are specified. then the pit slope is calculated. these should be obtained in order to define known slopes within the GEMS framework. there can only be two variables in defining a bench if the bench height is given. one parameter that is chosen. Pit Slopes: Pit Slope Angle. or batter angle to these areas. there is one parameter that remains constant. and Batter Angle As the following image shows. The third parameter is calculated from the other two. then the batter angle is calculated. berm width. Here are some examples of the relationships: • If the batter angle and pit slope are specified. and the third is calculated. Page 36 of 47 . Once the 3D ring or solid is complete. Create a single geotechnical domain as either a solid or 3D ring to represent an area where the pit slope. 2. Page 37 of 47 . On the Pit Design tab of the Rock Codes profile. Blending between domains will be discussed in a later section of the manual. 3. click OK. The rock codes can be created under the menu Format > Other Profiles > Rock Codes. For this reason. you should assign to it the desired rock code. and be sure to not have any of them overlap. Create as many geotechnical domains as needed. Usually. the usual method of handling slope regions is as follows: 1. or berm width (or a combination of two of these elements) is known. type the particular slope constraints for a domain. Make sure each one is assigned a rock code. they are given names that can be recognised as non-geological codes. Save the object. Define several rock codes that represent a slope domain. batter angle. When you are done.Advanced Pit Design Variable Pit Slopes Although it is possible to use actual structural geological models for defining pit slope domains. Note: A 3D ring acts outwardly beyond the limits of the plane that it is constructed on. it is more common to rework the structural geological model into a geotechnical model (as local geotechnical parameters such as joints and faults contribute to slope stability). When you proceed with your pit design. the slope properties of your 3D Rings/Solids will be observed. and choose the appropriate object type for pit slopes generation from the list of the pit Properties. 6. Page 38 of 47 . Please refer to the following Blending and Variable Pit Slope Domain sections of this manual for details on how these values are applied. Open all of your geotechnical lines/solids.Advanced Pit Design Variable Pit Slopes 4. Create a new pit. 5. Advanced Pit Design Variable Pit Slopes Blending? The term blending is used for letting GEMS gradually vary the pit slope. three different operations will occur: Page 39 of 47 . The figure explains the term. Depending on which of the three is chosen. select the General tab to define wherefore the variable slope domain is obtained (Obtain variable pit slopes from). berm width. or batter angle between two domains. and select Properties). Defining Slope Domains for Your Pit In the “Pit” Properties dialog box (right-click the pit. The options are as follow: • 3D rings (refer to all space. not just a specific elevation) • Geology solids • Defaults (no variable pit slopes) The Variable pit slope domain is the value that comes from your rock code profile. and have the program compute the different pit slope angles. where α = batter angle ⎝ H − W tan θ ⎠ α = tan −1 ⎜ Once the benching pattern is decided (triple-benching. two benches each with a berm width of zero followed by one bench with a berm width of 20 metres). enter this and all other pit design information into the Benches tab in your pit properties. In the image below a double-bench is shown. triple-benching means putting a safety berm only every third bench. To calculate this batter angle you’ll have to assume a berm width of 0 every other bench (for double benching. Double-benching is the ability to eliminate the berm from every second bench. The third domain is calculated based on the two known values. you can click Check Slope Angle. Pay special attention when multi-benching with Pit/Ramp Design. If at any point during your design. Multi-Benching Pit/Ramp Design has the ability to perform multi-benching should the wall rock prove competent. The following equations can be used to calculate your batter angle. Similarly. Benches tab).berm height) W = Berm width ⎛ H tan θ ⎞ ⎟ . you must specify the batter angle and berm width as the variables to edit manually. α. This flexibility specifies that some benches do not need berms.to . you are unsure if you are inside a geologic domain.Advanced Pit Design Multi-Benching Selected Variable Slope Domain Calculated Domain Constant Domain Batter angle Pit slope angle Berm width Pit slope angle Batter angle Berm width Berm width Pit slope angle Batter angle The “constant domain” is obtained from the bench parameters listed off on the Bench Definition Information tab in the properties for each pit. To correctly set up the bench parameters in the Bench Editor (“Pit” Properties dialog box. Page 40 of 47 . Before you multi-bench in GEMS you’ll need to perform some additional calculations in order to find an appropriate batter angle to achieve the desired pit slope. or for each two out of three benches when triple-benching). θ = Overall pit slope angle b = bench height H = Height (berm . berm width. the overall pit slope angle equals the pit slope angle in the Bench Editor. the pit slope angle can vary from bench to bench. however. which allows you to view the attribute. the berm width changes from bench to bench. Choose Polyline> Vertex > View/Edit (Real Coordinates) to open the Pit Design Feature Vertex Editor dialog box. Adding Ramps. after having completed bench expansions (using the Expand tools). Page 41 of 47 . Therefore. and Switchbacks When designing. In multi-benching. and batter angle for each bench. Slots.Advanced Pit Design Adding Ramps. batter angle. benches with and without berms will be produced. Thus. Caution: Each pit slope angle. for example. When triple benching. and berm width in the bench editor refers to the value of only one bench. and Switchbacks Ramps GEMS will create and project a ramp if a vertex in a toe or crest line has a ramp attribute. the pit slope angle does not refer to the toe of the first bench to the toe of the third bench (the one with the berm). Single benching (without choosing the option to use variable pit slope regions) uses the same pit slope angle. Slots. The pit slope angle is always measured from the toe of the current bench to the toe of the next bench. Advanced Pit Design Adding Ramps. 2. Change this to the blank. showing the ramp node as a cross Ending a Ramp If you do not want your ramp/slot to continue to the next bench. use the following procedure: 1. Creating a Ramp Entrance You can create a ramp entrance clicking or Tools > Pits and Dump Design > Create Ramp Entrance. Slots. . The polyline tool Polyline > Line > Create Ramp Entrance is another creation method which is used to convert a portion of an existing line to the ramp entrance. as well as clicking the crest/toe line for the entrance. Page 42 of 47 . click the ramp node cross. The name of the ramp will show up under Ramp/Slot Name. User-created ramp entrance. and Switchbacks The ramp node is shown in GEMS by a diagonal cross (see below). To end a ramp. and choose Polyline> Vertex > View/Edit (Real Coordinates). Ramp nodes always lie on crest/toe lines. Slots. They are defined in the same way as ramps in the pit properties and are also identified by crosses on crest and toe lines. When the Create line for opposite ramping tool is used. Opposite Ramping Ramps can also be built in the opposite direction from the current design by using the opposite ramping tool. the ramp will not continue. however. follow these steps. The same rules apply for ending or altering slots as for ramps. then normally the Expand one bench tool would descend a bench. if a pit is being built from top to bottom (the current bench is a crest). Create line for For example. . This tool is useful where large changes have been made to a ramp on the current bench. Choose Tools > Pits/Dumps Design > Create Slot Entrance or use the icon Page 43 of 47 to create a slot. and the toe becomes the active feature. Slots Slots are ramps which do not follow the curve of the pit. 1. the creating a slot involves an additional step. and Switchbacks 3.Advanced Pit Design Adding Ramps. To create a slot. the bench above the current is constructed including the ramp. and the change affects the previously created benches. When you expand the pit down another level. Advanced Pit Design Adding Ramps. You should now have something similar to the following figure: Page 44 of 47 . this line will point outwardly. Change the line type of the line digitised in step 2 to the slot line type. Then the Ramp/Slot attribute of the centre vertex must be changed to your slot linetype (using the command Polyline > Vertex > View/Edit (Real Coordinates)). This can be done in your Properties dialog box. Slots. If you are designing from your toe. If you are designing on a crest. 2. Choose Tools > Pits/Dumps Design > Create Toe/Crest/Slot Line to digitise a slot centreline from the slot node. 3. and Switchbacks An alternate creation method is to first digitise three vertices which represent the outsides and the midpoint of a slot entryway (Polyline > Vertex > Insert). This line should indicate the path that the slot will follow. this line will point towards the centre of your pit. Tools > Pits/Dumps Design > Switchbacks Choose Tools > Pits/Dumps Design > Create Switchback for automatic switchback creation. and edit the switchback by hand if required.Advanced Pit Design 4. 5. inserting points to provide room for the trucks to turn. Slots. you can click on the ramp node. provide the turning radius. Adding Ramps. Page 45 of 47 . After GEMS has created the switchback. Expand the benches. and changing the Ramp/Slot attribute for one of the points on the inside of the new ramp. Creating a switchback can also be done by hand editing. and Switchbacks Make your crest/toe the active feature again by clicking Activate Feature. This involves stopping the current ramp (delete the ramp name by editing the vertex). 25 top-down. 41   pit bottom-up. 18 domains defining. 22 first bench. 28 creating. 25   components. 44 splitting into multiple pits. 35 with ramps. 38. 37 blending pit slopes. 33 set up. 40 defining domains. 25 top. 30 errors. 19 creating first. 12 objects. 11 toolbar. 42 slots.Index   batter angles. 22 pit surface. 44 switchbacks. 12 ramps. 6 creating data benches. 31 creating a pit. 25 creating. 10 simple design. 5 structure flow. 46 pit slopes angle definition. 40 bottom-up. 25 pit objects ramps. 26 pit. 5 prerequisites. 9 custom. 16 principles. 11 pit slope angle. 38 variable. 10 Page 46 of 47 . 22 difference from pit. 30 switchbacks definition. 42   slots definition. 5 overview. 30 surface from SEG. 40 domains. 12 definition. 8 workspaces. 30 surface. 33 workspaces. 8 project view area. 33   menu commands. 37 calculating. 19 dump. 13 switchbacks. 14 surface from Whittle pit shells. 19 polylines. 25 quantity. 14. 46 symbols designing. 9 course outcomes. 12 theory. 26 benching multi. 37 plan view benches. 35 surface combining with topography. 16   designing fillet problems. 14 workspaces. 16 symbols. 22 difference from dump. 33 lines not projecting. 33   line segments. 40 dump creating. 26 first. 12 slots. 10 multi-benching. 13 objects. 16. 10   errors surface creation. 34 typical issues. 34   terms. 12 blending. 35 no ramps. 41 berm width. 12 objects. 41 benches adding. 30 creating. 9   ramps access. 31   fillet problems. 8 workspaces.Index buttons. 16 linking. 25 topography combining with surface. 16 Page 47 of 47 . 18 polylines. 10 creating. 14 shells. 30   Whittle pit shells. 14 workflow. 16 designing. 10 top-down. 14 SEG.