Carlson 30th Anniversary User Conference
April 7 – 10, 2013
IMPROVE YOUR SKILLS ● LOOK TO THE FUTURE ● CELEBRATE THE PAST
Carlson Mining – Faults and Strata Polylines
April 9, 2013 – Session 5
Presented By: Grant Wenker, PE
gwenker@carlsonsw.com
Faults and Strata Polylines
These two topics complement each other. They appear one after the other in the
StrataCalc menu of the Carlson Geology Module. The use of the Fault commands are
described below, followed by Strata Polylines.
Draw Fault Line
This command creates a 3D polyline that represents a fault line which is used by Fence
Diagram in the intersection mode, or in the Make Strata Grid File command. When the fence
line crosses the fault line, the strata will shift by the amount of the shift value of the fault line at
that point. This command is very similar to Carlson Draw > 3D Polyline command, in addition to
elevation for each vertex of the polyline this command prompts for fault shift or displacement.
This value is the amount of elevation difference from left to right across the fault line in the
direction of the line is drawn. The user is also prompted for the dip angle at the beginning, dip
angle does not have to be the same throughout the length of fault.
Edit Fault Line
This command is used to edit the fault line drawn using Draw Fault Line Command. It allows to
edit each vertex of the fault along with its shift displacement for each vertex and the dip angle of
the fault. The fault appears in the graphic window. There are buttons for pan, zoom in/out, rotate
and zoom extents. Each line of the spreadsheet may be edited to update the fault line. The Pick
button at the end of the row will switch to the plan view where the new location for that point can
be selected. The + Add Vertex button will add a point, the X Remove Vertex will delete a point,
and the Pick Location will move an existing point.
Calculate Fault Shift
This command assigns fault shift displacement to existing drawn fault polylines. The polylines
must be drawn ahead of time and they should follow the fault zones. After selecting the
polylines to process, the program prompts for drillholes to process. Then select a strata to
model. The fault shift is calculated by modeling the strata twice for each polyline. One model
excludes the drillholes on the left of the polyline and the other model excludes the drillholes on
the right. Then the elevation difference between the two models is used to assign the fault shifts
along the polyline.
Highlight Fault Lines
This command is used to highlight fault lines drawn using Draw Fault Line Command.
Identify Fault Lines
This command is used to identify fault lines drawn using Draw Fault Line Command. The lines
have to be drawn using Draw Fault Llne.
Select fault polyline to identify:
Vertex Strike
Dip
Shift Elevation
1
N 13°37'37" E 90.000 79.507 4790.000
2
N 13°37'37" E 90.000 55.497 4790.000
Select fault polyline to identify:
Vertex Strike
Dip
Shift Elevation
1
N 06°25'38" W 60.000 49.000 4829.917
2
N 44°11'07" W 60.000 49.000 4865.010
3
N 11°05'46" W 60.000 49.000 4854.985
4
N 11°05'46" W 60.000 49.000 4860.000
Select fault polyline to identify:
Vertex Strike
Dip
Shift Elevation
1
N 07°19'05" W 60.000 30.000 4794.993
2
N 47°41'01" W 60.000 25.000 4864.995
3
N 09°29'16" W 60.000 30.000 4810.022
4
N 09°29'16" W 60.000 30.000 4819.983
Select fault polyline to identify:
Vertex Strike
Dip
Shift Elevation
1
N 06°27'29" E 60.000 30.000 4770.343
2
N 45°33'55" E 60.000 30.000 4804.915
3
N 10°49'55" E 60.000 30.000 4879.947
4
N 10°49'55" E 60.000 30.000 4770.057
Draw Fault Surface
This command draws fault surfaces as 3D faces at dip angles from fault lines drawn using Draw
Fault Line Command. It will prompt to either draw the fault face just to the depth of the
displacement, or a total depth below the surface can be entered, such as 300, and the fault is
drawn that deep.
Draw Heave Zone
This command creates closed polylines that represent the fault heave zones where the material
is broken up and not mineable. These polylines can then be used as exclusion areas in routine
like Strata Isopach maps to avoid contours in those areas. They can also be tagged as Strata
Limit Polylines for exclusion for volumes and to delete the area in a Fence Diagram.
The command will use either an existing elevation grid file, or it will model from drillholes on
screen. If there are multiple seams that are faulted, each one will have a slightly different area
along the fault. Shown here is a result of drawing the heave zones. Most zones will run parallel
to the faults, with the distance away from the fault based on the displacement of shift of the
fault.
Create Strata Polylines at Faults
This command creates strata elevation polylines at the intersection of fault surfaces with strata
models. These can then be used to help create the strata grid files to make a better elevation
model.
Apply Faults to Grids
This command is used to offset the grid values of an existing grid file. It saves a new grid file
with the values offset based on the fault lines drawn with the Draw Fault line command. The
Fault Influence Distance is the offset distance away from the fault lines that will be used to
transition from the original grid to the faulted values. This method is used to update a grid file
and not have to recreate them over.
Make Strata Grid Files
This series of commands will use the fault polylines and displace the grid surface at the fault. A
3D view of a faulted grid is shown here.
Fence Diagram
The faults can be displayed two different ways on a Fence Diagram. The first option is to just
show the grids in their actual dip, as seen here.
The second method is to show them with the Draw Faults option turned on. This will draw the
faults as a clean shift of the surfaces, with no grids shown along the fault. The buffer offset is
the distance it will use either side of the fault to clean up the grids. Shown here is the same
section with the faults drawn.
Input-Edit Strike/Dip Symbols
This command works in an editor where the strike and dip symbols can be added, deleted or
edited in a spreadsheet type editor. There are options for reporting and importing from an
external text file to bring the symbols in.
Draw Strike - Dip Symbols
This command draws the standard strike-dip symbol based on user defined input. It has an
option for entering and labeling a description. If no description is desired, then leave it blank.
The strike and dip entered in the window will orientate the symbol placement. There are settings
for symbol and text size, as well as layers. If these are drawn large enough, they can be used
for Strata Polylines.
Strata Polylines
Strata polylines are 3D polylines that represent thickness, top, or bottom elevations of strata.
They are used to assist in making the grids with the drillholes and channel samples.
Tag Strata Polylines
To explain Strata Polylines and the effect they can have on your geologic model, consider the
following. The Draw 3D Polyline command is used to create the following polyline to represent
the bottom elevation of the C1 strata.
Using 3D Poly Offset as an example to offset the polyline 15ft horizontally and vertically to
represents the bottom of the OB strata, which is also the top of the C1. Finally, use Tag Strata
Polylines to tag the 3D polys to the respective strata and the lines as bottom elevation.
We build a Pre-Calc Grid by creating a grid of the surface and each strata bottom elevation without using
the Strata Polylines first, and then repeat using the strata polylines. We draw the fences below and you
can see the impact the strata polylines have on the geologic model. The top section used the Strata
Polyllines, the bottom one used just the drillholes.
B. Offset Strata Polylines
This command creates additional strata elevation polylines offset by the strata thickness from a
reference/starting strata polyline for elevation. This is useful for manually creating faults where
all the seams are offset along the elevation strata polylines. The first prompt is to open or create
an offset strata polylines file (*.OSP). The first column is the strata/bed name attached to the
strata polyline. The button next to them brings up the list of defined strata. A Reference polyline
is one that already exists and this is the one that will be offset from The thickness to offset the
new polylines can either be entered as a value (+/-) or as a thickness grid file. The layer is the
layer that the reference polyline is on, and the layer it will draw the new polylines on. The
resulting new strata polylines can be used for more accurate modeling elevations.
The above drawing shows the offset Strata Polylines for the other strata. This will help make a
better elevation grid with the new structure enhancements.
Report Strata Polylines
This command reports all Strata Limit Polylines that are in the drawing. The report contains the
layers, area, XY of the polyline endpoints, and whether it is an inclusion or exclusion limit
polyline.
Strata Polylines
#PageNum
Strata
Type
Start Y
Start X
Layer
C1
Bottom Elevation 1970836.10 1457858.76 SP_C1
C2
Bottom Elevation 1970836.10 1457858.76 SP_C2
IB
Bottom Elevation 1970836.10 1457858.76 SP_IB
OB
Bottom Elevation 1970836.10 1457858.76 SP_OB
----- Grand Total ----varies Bottom Elevation 9854194.98 7289297.81 varies
Highlight Strata Polylines
This command simply highlights the named strata limit polylines in the drawing. A regen of the
screen will unselect the polylines.
Identify Strata Polylines
This command reports the strata names assigned to a polyline for strata limits. There is the
option to select one and view its name, to pick inside and have it identify which lines enclose
that point, or to search the drawing and automatically highlight and report all that it finds. If the
hatch option is used, then the hatch window appears where the hatch pattern can be selected
for each limit polyline.
Command Prompt
Select strata polyline to identify:
Strata Name: C2 Type: Bottom Elevation
Untag Strata Polylines
This command removes the strata limit assignments from the selected polylines.
Prompts
Select limit polylines to have limit data removed.
Select objects: pick the limit polylines