Define Drillhole

Function

Define Drillhole is a prerequisite to creating, importing and processing drillholes. This is a configuration file containing settings for drillhole entry and processing. There is no geologic data stored in this .CH file. The following information is set by Define Drillhole:

• Method to locate strata: When using Place Drillholes, this setting is what will be prompted for. There are three choices: Thickness, Elevation or Depth. If importing from an external file, data will come in no matter what is set here, this is just for prompting with Place Drillhole.
  
• Prompt for: This option is used for preparing the prompting in the Place Drillhole command. There is the option to prompt to enter Non-key strata information, a Bed Name and Drillhole type. During Place Drillholes, each strata must be set as either "Key" or "Non-Key". Then you will be prompted to enter values for the corresponding attribute names if any are entered here. Typically, coal, limestone, trona and ore are Key and overburden, partings and waste strata are Non-Key. Distinguishing between Key and Non-Key allows for different sets of attributes and enables StrataCalc to calculate the Key to Non-Key strip ratios in the Surface Reserves. When placing drillholes with the Place Drillhole command, every strata must be assigned a bottom elevation and a thickness. The bottom elevation is the elevation of the bottom of the strata. There are different methods for entering this information. Which method to use is specified in Define Drillhole and depends on what kind of data you have. If there is data only for the key strata, then don't specify the Non-Key option for prompting. This option will prompt for the thickness and elevation of the key strata, and then it will fill in the distance up to the last key strata with a non-key strata named after the key strata's name plus "_OB" at the end. On the other hand, if there is data for all the strata then do turn on NonKey and enter it as well. In this case, either the thickness or elevation of each strata must be entered. Entering both thickness and elevation is not necessary because given one the other can be found from the neighboring strata. So there is a choice to enter each strata by thickness or by elevation. The elevation can be specified as either the absolute bottom elevation or as the elevation difference between the surface elevation of the drillhole and the bottom elevation of the strata. Finally, both thickness and elevation can be entered in feet or with both feet and inches. The Bed name option will prompt for the bed name in Place Drillhole. Otherwise the bed names will be set to blank. The Drillhole type option will prompt for the drillhole type number. Otherwise the drillhole type will be set to the first one on the list, 0.
• Enter Values in: This also mostly applies to Place Drillhole, prompting for thickness. Set to Inches or Feet/Meter (drawing units), whichever is being entered.
  
• List to edit: These are strata and drillhole attributes that can be predefined and set for the drillholes. To enter new ones, type the name in the Value window and choose Add or Update. Remove takes them off the list. Strata attributes can be specific to Key or Non-Key strata.There is no limit to the number of attributes that may be entered. The only limit is in file size when storing the drillholes in the drawing as Extended Entity Data (EED). This has an AutoCAD limit of 16383 bytes of text. To see how much is stored in the drillhole, or any object, type XDLIST and select it. It takes several hundred qualities for many strata to get to that limit. For more storage, the Use External Database option should be used, where there is no limit on the amount a data stored per drillhole.  To use attributes in StrataCalc, only the attribute names need to be specified in Define DrillHole. Sample attribute names include sulfer, BTU, acid, base, moisture, etc. Thereare a few reserved names. Attribute FERM is assumed to be a Ferm Code. Another attribute is used to define horizons. This name is defined in Define Horizon Codes and is HORIZON by default. Attribute names that begins with the '=' symbol defines an equation and its value is calculated using values of other attributes. The attribute name LBS may be used in equations to represent strata density. The following are examples of equation attributes: 

  =LBS*SULF/(10^6*BTU)

  =MOIST/LBS

  =BTU/1000

1. - the attributes described in drillhole definition (Define Drillhole)
2. - the attributes assigned to strata definition (Define Strata)
3. - the attributes added to particular strata in particular drillhole (Edit Drillhole, Drillhole Import, Drillhole Data Sheet)

Such a variety of attribute assignment methods provide high flexibility in attribute usage.

Drillhole descriptions are intended for storing of drillhole specific information in the drillhole. One general drillhole Description is predefined and user may define any number of specific drillhole descriptions. Typical additional description examples are DRILLER, DATE, TOWNSHIP, and etc. You will be prompted for values of these descriptions in Place Drillhole.

• Set Quality Names: This is an option for defining how well or with which method the hole location was surveyed. There are two variables in the drillhole for this. One is the XY Quality and the other is the Z Quality. There are 6 types available and may be customized to the users need. The Set Quality Names button brings up a dialog for customizing the names used for the drillhole X-Y and Z quality types. These names are used in prompting and reports.

• Drillhole Types: All drillholes have a drillhole type field that is a number from 0 to 8. The drillhole type field can be used to group the drillholes by category. For each drillhole type, you can set the type name (ie. "Corehole", "Complete" or "Outcrop"), the drillhole symbol and drillhole layer. To change a drillhole type name, first choose the drillhole type and then type in the new name in the edit field. To change the symbol for a drillhole type, first choose the drillhole type and then pick the Select Symbol button. You will be prompted to choose a symbol from the Symbol Selection dialog. The Edit Drillhole and Drillhole Spread Sheet commands can be used to modify the drillhole types.When importing from an external file, such as a *.CSV file, then the types must be numbered from 0 to 8 in the file. 0 is the first type and 8 is the last.
  
• Set Layers: This routine brings up a dialog for entering the layer names for all the possible drillhole types. One suggestion here is to prefix the drillhole layers the same, such as with DH-, that way in the Layer Properties Manager, they are grouped together in a row for ease of selection for freezing and thawing. Colors can be set for each drillhole layer by selecting the color button.
  

• Select Symbol: Choosing this button sets the symbol used for each drillhole type. Highlight the drillhole type and then choose the desired symbol. Carlson has 100 predefined symbols, and custom symbols may be added from within the COGO module in the symbol library manager.
  

• Symbol Size: This is the size of the drillhole symbol in drawing units. Most of the time, it is the diameter of the symbol, depending on how the symbol was drawn initially in the block drawing.
  
• Separate Drillhole Layers by Type: The Separate Drillhole Layers by Type option will draw the drillhole symbols on the layer defined for the drillhole type. Otherwise all drillhole symbols are created on the DRILLHOLE layer. To set the layers for the drillhole types, turn on the Separate Drillhole Layers option and then pick the Set Layers button.
• Strata Density: The Strata Density field is the default density used to calculate strata tons in routines like Surface Mine Reserves. Density can also be made strata-specific by using the Define Strata command. In Surface Mine Reserves, the Use Density Attribute option can be used to model the density for each strata by using a strata attribute.
• Use External Database / Select File: Carlson has several options for storing the geologic data. This is the option for setting which method to use. If this is left off, then the geologic data is stored in the AutoCAD drawing, within the symbol as Extended Entity Data. (EED). This is a very clean and simple approach, and will run very efficiently. There is, however, a limit. The limit is AutoCAD's limit of  16,383 bytes available for data storage per entity (symbol). To see this, type at the AutoCAD command line, XDLIST and follow the prompts:
  
XDLIST
Select object: Pick any object
Application name <*>: Hit Enter for wildcard.
No Xdata associated with Application Name(s).
Object has 16383 bytes of Xdata space available.
The limit can be reached with many lines of data and quality attributes. These will have to number in the hundreds, but it can happen. It can also be dangerous to store the data in the symbol. One mistake with the erase or delete button, and the symbol and all of its geologic data is erased. That is why we have options. The method of data storage (EED vs External) is displayed in the Edit Drillhole command for each drillhole. The External Database can be either Microsoft Excel or Access, but most people use Access over Excel. Shown below are formats for both types. Running the Import Drillhole, or Place Drillhole commands will draw the symbols on the screen and also add the holes to the database.

The Excel format has two tables, one for drillhole (collar) data and one for strata, structural and quality data.

The same applies to the Access Database format shown next. There are two tables. One called Table_Drillhole and one Table_Strata.

Prompts

Select Exiting/New Drillhole Configuration File: Selection Dialog Box
Select Drillhole Configuration File Selection Dialog Box
Specify a file name in which to store the drillhole definition.
Define Drillhole Dialog

Drop-Down Menu Location: Drillhole
Keyboard Command: chdef
Files: \lsp\corehole.arx, \lsp\corehole.dcl, \lsp\defcore.lsp