For each strata in the drillholes, this routine can generate isopach maps, or isolines of the strata thickness, bottom elevation, and attributes such as moisture, sulfur, and BTU. An isopach map is essentially a contour map of the specified strata values.
At the start, there is an option to isopach from either from Grid File or Drillholes From Screen. The file option will contour from stored grid files. In the screen option, the program reads the strata data from the selected drillholes and builds strata models on-the-fly while applying pinch out and conformance as set in Configure, Mining. Then the program shows a list of strata. After selecting a strata to process, the program cycles through all the possible strata values. When one of these values is chosen, the contour options dialog box is activated which allows the contouring parameters for the isopach map to be set.
The Hatch Zones option will fill in the area between contours with a hatch pattern and color for that zone. For example, hatch zones will create a thickness isopach map with the 0-2 area in blue, 2-4 in green and 4-6 in red etc. The Polyline topology option will create closed polylines of each contour zone. This can be used for GIS type applications in other modules.
The Draw Drillhole Labels option draws text next to each
drillhole with the value that
was used for contouring. After creating the contours with this routine,
the contours can be
labeled and highlighted with the contour embellishment commands in the
Contour drop-down of
the Contour-DTM module. The first window determines the source of the
isopach and the modeling process if from drillholes. Use
Triangulation Subdivision will be applied to the modeling with
triangulation. This process is documented in the Make Grid command.
Create Composite Contours will allow for multiple strata to be selected
at once, to create a "total coal" thickness isopach for example.
There are two different dialogs, depending if you are contouring
from drillholes or a grid. They are both shown below.
Shown above is an Isopach map with legend using hatch zones. Below is a typical isopach without hatching.
Drop-Down Menu Location: StrataCalc
Keyboard Command: chiso
File Names: \lsp\ch_cntrs.lsp,
\lsp\makegrid.arx, \lsp\corehole.dcl