4.1 Introduction

This module enables the user to enter or calculate fixed length or bench composited drill hole data, creating a composite drill hole MicroMODEL database. Once the composite data is entered or calculated, MicroMODEL has a suite of display and statistical programs that can be used to verify and analyze the composited drill hole database.

The Compositing Sub-Menu appears below:

This menu choice enables the user to invoke commands and run external programs without exiting MicroMODEL. This program is simply a command shell. The user enters as many commands as desired. Type "EXIT" at the command prompt to return to MicroMODEL.

There are three methods available to the user for calculating composites for inclusion in a composited drill hole database:

Drill Hole Compositing: The composites are generated from the collar of the hole downward at a constant user specified composite length. The rock codes for each composite can be extracted from the previously created rock model or from the majority rock code in the corresponding sampled drill hole intervals.

Mixed Compositing: An attempt is made to Bench Composite a drill hole, where the start of the composite interval is at the top elevation (crest) of the corresponding bench and the end of the composite is at the bottom elevation (toe) of the corresponding bench. This composite length is limited by a user defined maximum composite length. If the drill hole cannot be bench composited because the composite length is longer than the maximum composite length, due to a shallow plunge, the hole is then drill hole composited as described. In the same manner as in drill hole compositing, the composite rock codes can be extracted from the rock model or from the corresponding rock codes in the sampled drill hole intervals.

Rock Unit Compositing: Composite values can be calculated as a weighted average, spanning a single geologic unit (rock code). The values used to determine the composite value will not cross a geologic boundary, as defined by the rock code. The user will specify the required composite length, and the minimum acceptable length.

In order to use this program to calculate composite data from the sample drill hole database, the number of composite data labels must correspond with the number of sample data labels. For ease in understanding, it is recommended that the composite data label names reflect name of the corresponding sample data label. The compositing program always composites the sample drill hole data labels in a one-to-one correspondence with the composite data labels.

The three methods of compositing are illustrated in the following tables. The first table lists the original drillhole assay interval information. The others list the results of the three different compositing methods. Figure 4.1 gives a graphical representation of the tables. Compositing is further discussed in Volume I, Sections 2.4 and 4.4.

                                    FIGURE 4.1
                               COMPOSITING METHODS

Drillhole Collar Information

    DRILLHOLE NAME : DDH-01
          NORTHING :  11014.500
           EASTING :  20290.700
  COLLAR ELEVATION :   5673.600
     DIP-DIRECTION :     90.00
         DIP ANGLE :     45.00
             DEPTH :    188.00
 NUMBER OF SAMPLES :   21
 NUMBER OF SURVEYS :   0

The ANSWERSET NAME identifies this set of answers.

The user must choose which method of compositing to use: DRILL HOLE, MIXED, or ROCK UNIT.

NOTE: For Seam Modeling, rock unit compositing is always used to calculate the composite values.

The user must specify the METHOD TO BE USED TO ASSIGN ROCK CODES TO THE COMPOSITED INTERVALS. Extracting rock codes from the ROCK MODEL results in the program determining which block (row, column, level) contains the composite midpoint location, and assigning the block model rock code for that block to the composite. This method is generally used when a representative rock model has been constructed and rock codes are used to control the grade modelling. This method will not work unless a rock model has been created under Module 4, Rock Modelling.

Using the SAMPLED DRILL HOLE INTERVALS to obtain the rock codes for the composites instructs the Compositing program to calculate which rock code from the sampled intervals occupies the largest part of the composite length. The composite then receives this most common sampled rock code. This method is often used when thorough control of the grade modelling by rock type is not necessary.

If drill hole compositing or rock unit compositing is requested, the user must specify the desired COMPOSITE LENGTH. The MINIMUM COMPOSITE LENGTH controls how long composites at the bottom of the drill hole must be to receive composited assay values. If the bottom composite length is less than the minimum composite length, then the bottom composite is assigned unsampled assay values for all labels.

Mixed compositing requires both a minimum and maximum acceptable composite length. The MINIMUM COMPOSITE LENGTH controls how long composites at the top and bottom of the drill hole must be to receive composited assay values. If the top and/or bottom composited lengths are less than the minimum composite length, then they are assigned unsampled assay values for all labels. The MAXIMUM COMPOSITE LENGTH determines if shallow plunging drill holes should be bench composited or drill hole composited. With shallow drill holes it is possible to have composite lengths which are much longer than normal composite lengths. This may be undesirable, and the Maximum Composite Length limits the length of the composite. If a drill hole is encountered that exceeds the Maximum Composite Length, then the drill hole is automatically composited at a fixed length down the hole (drill hole compositing) using a composited interval length equal to the bench height.

This program replaces the interactive drillhole input program from previous versions of MicroMODEL. It allows the user to convert a set of separate ASCII text files containing drillhole collar, survey, assay, and optional geology information into a single, standard MicroMODEL input file that can be read with the next program choice (4.5). These separate text files can easily be created with any spreadsheet program, or with a database program such as MicroSoft Access. Refer to Section 1.4 for details.

This program allows the user to read an existing ASCII composited drill hole database into MicroMODEL. The program works in exactly the same manner as the program listed in section 1.5, Read in an Existing Drill Hole Database. The only difference is that the user is creating data stored in the composited data files (CHED, COMP), as opposed to creating data stored in the sample interval files (SHED, SAMP). Refer to section 1.5 for details.

This program will output all or part of the composited drill hole database. It works in exactly the same manner as the program described in section 1.6, Print Drill Hole Database. The only difference is that the program will output data stored in the composited data files (CHED, COMP), as opposed to data stored in the sample interval files (SHED, SAMP). Table 4-2 contains examples of both Report Format and Free Format Output. Refer to section 1.6 for details.

The Database Editing Menu allows the user to edit and manipulate the entered composite drill hole data. These programs works in exactly the same manner as the programs described in section 1.7, Database Editing. The only difference is that the user is working on data stored in the composited data files (CHED, COMP), as opposed to working on data stored in the sample interval files (SHED, SAMP). Refer to section 1.7 for details.

This option allows the user to produce a plan view map (plot) of the drill hole collar locations. Refer to section 1.8 for details.

This option allows the user to produce a plan view map of composited drill hole pierce point locations at the mid point elevation for a specified bench. This program works in exactly the same manner as the program described in section 1.9, Plot Drill Hole Bench Locations. The only difference is that the user is displaying data stored in the composited data files (CHED, COMP), as opposed to displaying data stored in the sample interval files (SHED, SAMP). Refer to section 1.9 for details.

This program produces a cross section plot of drill holes and the topographic projection onto any user specified vertical plane. The user may plot either drill hole sample intervals, drill hole composite intervals, or both. Refer to section 1.10 for details.

This option allows the user to perform basic statistics on the current composite data label in the Composite Drill Hole database. It works in exactly the same manner as the program that calculates Sample Frequency Analysis and Basic Statistics, except that it works on data stored in the composited data files (CHED, COMP), as opposed to working on data stored in the sample interval files (SHED, SAMP). Refer to section 1.11 for details.

This option allows the user to produce an unscaled cumulative frequency curve plot of the composite drill hole data. It works in exactly the same manner as the program that performs Sample Cumulative Frequency Analysis, except that it works on data stored in the composited data files (CHED, COMP), as opposed to working on data stored in the sample interval files (SHED, SAMP). Refer to section 1.12 for details.

This option allows the user to produce a correlation analysis (linear regression) plot between any two labels in the composite drill hole database. It works in exactly the same manner as the program that performs Sample Correlation Analysis, except that it works on data stored in the composited data files (CHED, COMP), as opposed to working on data stored in the sample interval files (SHED, SAMP). Refer to section 1.13 for details.

This program allows the user to write composite label data that has been artifically massaged into existing composite data labels in the composite drill hole database. It works in exactly the same manner as the program that performs Sample Manipulation, except that it works on data stored in the composited data files (CHED, COMP), as opposed to working on data stored in the sample interval files (SHED, SAMP). Refer to section 1.14 for details.

This option allows the user to delete all output files created in the Data Entry Module that are no longer needed in the MicroMODEL system. The files that will be deleted are listed when the program is invoked. The output files that are deleted can always be recreated by MicroMODEL at a later date as needed. Periodically running this program increases usable disk space.