Fence Diagram

Function

Fence Diagram produces a profile of the surface and strata along the selected baseline polyline--a geological cross-section. This command is somewhat similar to the command Profile from Surface Model. Fence diagrams are a good way to verify that the strata model is correct-especially when the drillholes are plotted on them with Draw Geologic Column. The first step is to draw a baseline polyline in plan view from which the fence diagram is created. This polyline can have more than two points and can either go to drillholes or between them. The Fence Diagram can either be drawn on a 2D grid off to the side, or in 3D, and rotated around in 3D. Fence Diagram derives the strata profiles by either gridding, a Precalculated Grids file, or intersection method. There are many options for scale, hatching and labeling. They are explained separately below. 

• Draw Fence Diagram: In Real World Coordinates or On a 2-D Grid: There are two options for choosing the location of the fence diagram. It can be drawn in real world coordinates in 3D, directly below the fence line drawn in plan view. It will have to be rotated on the X axis and spun around on the Z axis to see it. The other option is to draw it off to the side at a user defined spot, in a 2D grid. Similar to the command Draw Profile. Shown here are 3 Fence Diagrams drawn in Real World Coordinates, hatched by strata attribute.
  

• Ignore Zero Elevations: When using the Grids from Drillholes or Intersection methods, the surface topo will be modeled by anything on screen. Selecting this will ignore anything that has an elevation. This is recommended unless the mine is near sea-level.
  
• Fence Extraction Method: The Grids from Drillholes method creates a grid model of each strata found in the drillholes "on-the-fly". The program will prompt for the modeling method to use (ie Triangulation or Inverse Distance). These modeling methods are described in the command Make Strata Grid Files for more details. The Pre-Calculated Grids option will use a pre-defined PreCalc file that contains grids and seam names. The PreCalc is made under Drillhole-Define PreCalc Grids. The Intersection method triangulates the drillholes and then finds the intersection of the triangulation mesh and the polyline. In order to obtain data for the strata with the intersection method, the polyline must have at least one drillhole on each side. It is the only way to see a fault in a fence diagram when using the drillholes. Grids from Drillholes does not honor fault lines.
  
• Horizontal Scale: This is the horizontal scale that will be used to draw the fence diagram. It usually matches the horizontal scale of the drawing.
  
• Vertical Scale: This is the vertical scale that will be used to draw the fence diagram. It usually matches the vertical scale of the drawing. If it is the same as the horizontal scale, the fence will be drawn at a 1:1, with no vertical exaggeration. To get a 2X vertical exaggeration, the vertical scale must be 1/2 of the horizontal scale such as 50H/25V. The same drawing distance represents 50 horizontally and 25 vertically. So it must be twice as tall vertically to equal 50.
  
• Horizontal Axis Grid Interval: This is how often a grid line and tick mark will appear horizontally along the X-axis.
  
• Vertical Axis Grid Interval: This is how often a grid line and tick mark will appear vertically along the Y-axis.
• Horizontal Axis Text Interval: This is how often a text label will be drawn on the fence diagram axis. It does not have to match the Grid Interval, but it can.
  
• Vertical Axis Text Interval: This is how often a text label will be drawn on the fence diagram axis. It does not have to match the Grid Interval, but it can.
• Starting Station: This is the station that is labeled at the beginning of the fence diagram horizontal X-axis grid. By default it is set to 0.
  
• Axis Text Size Scaler: This is the scaler that is multiplied by the horizontal scale to determine the text size. It applies to both the X and Y axis.
  
• Grid Ticks Only: This option will just draw tick marks at the set grid interval for both horizontal and vertical axis.
  
• Draw Plan View: The Draw Plan View option will graph the drillhole locations above the fence diagram. For this graph, each drillhole is projected onto the baseline polyline to find the station and offset of the drillhole.
• Plan Vertical Scale: This is the scale factor for the Plan View drawn above the fence diagram. It is separate, so that the text and drillholes drawn can be differenct then the fence diagram scale settings if desired.
  
• Station by another reference centerline: This option will station the horizontal X-axis by a predifined centerline CL file. The centerline file will be prompted for during the routine.
  
• Draw Surface Polyline: This option will draw a new polyline along the surface of the fence diagram. It is required if the fence diagram has a pit in it. The surface polyline will not be continuous across the entire fence if there is a pit, as it is broken by outcropping seams. Routines such as Cut and Place run on Fence Diagrams require the surface polyline extends across the pit, so it has a place to spoil. The other, broken surface polylines can be erased if the continuous one is used.
  
• Label Northing-Easting: This option labels the Northing and Easting coordinates along the bottom of the fence diagram at every vertice on the fence line that is drawn in plan view. An example is shown below.
  

• Layer Settings: Layers of fence diagram polylines contains 3 options for drawing the polylines layers.  The first one, Layer by Strata Name, will create a layer for each strata name found in the drillholes or PreCalc. The second option, NonKey on Same Layer, will draw the Key strata and layerize them by strata name. All of the NonKey strata will be drawn on the Fence layer, or any user defined layer  in the dialog box. The last option, All on Same Layer, will draw all the polylines on the defined layer "Fence" that appears in the dialog, or any user defined layer.  There are separate layers for the Pit Label layer, the Surface Polyline, the Grid Lines and the Grid Text layers.
  
• Label Pit Lines with Tick Mark: When the Label Pit Polylines with Tick Mark option is on, the program will prompt you to select polylines with attached pit/site names. These pit names will be labeled with a tick mark and labeled along the bottom of the fence diagram grid at the position where the fence plan view polyline crosses the pit polylines. This is useful for dragline design commands such as Cut and Place. 
  
• Hatch Fence: Turn this option on to hatch the strata in the fence, otherwise leave it off to just draw polylines. The strata hatch patterns are defined in the Define Strata command. If this is selected, then the hatch patterns defined there will be used. If a strata exists that is not defined, it will use the default hatch in Pattern Name.
• Pattern Name: The default hatch pattern is used if there is no pattern defined for that strata. This can be mdst or SOLID, for example.
  
• Scaler: This is the scale factor that is applied to the hatch pattern in the Fence diagram. A factor of 1.00 here will use the default hatch pattern scale factor set with Drawing Setup.
  
• Rotate: The Rotate option for hatching rotates the hatch pattern to best fit the angle of the strata. A hatch pattern can have only one rotation, so rotating will not be effective for a strata with multiple rotations. There is also the Azimuth option in the Define Strata command to rotate the hatch.
  
• Clip Intersecting Strata: This option is useful to check for crossing grid files. It is ON by default. Turning the option off will draw the polylines as they are in the grids or modeled from the drillholes. It is only active if the hatch option is turned off, and the fence is just drawn as polylines. Shown below is an example of the crossing polylines in a Fence Diagram. This means the grids or modeling might be suspect and should be cleaned up.
  
• Draw Key Strata Only: This option will draw and hatch just the Key strata on the fence diagram. The Non-Key intervals found in between the Key will be left as empty gaps.
• Max Drillhole Offset from Line: A maximum distance offset from the baseline polyline can be specified to filter out drillholes beyond the area of interest.

• Hatch Key Strata Only:  This option will just hatch inside the Key strata that are drawn. The NonKey strata will be just polylines, with no hatch inside. Shown here is an example that has just the Key strata hatched, but also the limit lines are used to define the breaks between the splitting seams. Notice the nice, veritcal contact from a full seam to a split seam.
  

• Hatch By Block Model: This option will hatch the seams using the GPF Grade Parameter File and the Block Model BLK files. A legend of the grades can be drawn also in the Define Grade Parameter screen. This is a great option to use to show the changing quality not only horizontally, but also verticallly in the geology.
  

• Hatch By Strata Attribute: This option is similar to Hatch by Block Model, except there is no Grade Parameter File required. It will look at look at the quality attributes found in the PreCalc, or in the drillholes, and bring up a list. Select an attribute to hatch by. Then a color pallette will appear, allowing to set the colors and ranges of the different "zones". This will just change the hatch horizontally across the strata, not vertically as the Block Model does. Shown below is an example of coal seams colored by BTU.
  

• Draw Legend: Use the Draw Legend option to make a legend of the strata hatch patterns and colors. There will be a prompt to pick the location to draw the legend.
  
• Legend Scale: This is the scale factor to size the legend.
  
• Bottom Hatch Scaler: This is the scale factor to use for the strata that appears at the very bottom of the fence diagram. If using a solid, then no scale is applied, but any other hatch pattern will use a scale factor.
  
• Load/Save: All of the switches and settings can be saved and loaded with these buttons. It creates a FEN file containing all of the settings.
  

Prompts

Fence Diagram Settings dialog box
Select polyline to pull fence diagram from: pick the polyline
Select surface entities & at least 3 drillholes.
Select objects: Select the drillhole symbols and surface entities. Surface entities can include points, lines, and polylines.
Reading points ... 139
Reading drillholes ...
Choose modeling method (<Triangulation>/Inverse dist/Kriging/Polynomial/LeastSq)? Press Enter
Pick the lower left corner for the fence diagram: pick a point in a clear area of the drawing

Drop-Down Menu Location: under StrataCalc
Keyboard Command: fence
Files: fence.lsp, makegrid.arx, corehole.dcl