Subheadings for this chapter are as follows:

The limitations described in this section apply to MicroMODEL version 7.0.

5.1 Model Limitations

The maximum grid dimensions allowed by MicroMODEL are 2048 rows, 2048 columns and 2048 levels. There is no limit on the block dimensions within the model. Careful selection of the model size, orientation, and block dimensions will minimize the number of blocks (and computation time) without sacrificing geometrical accuracy.

Up to 99 labels (e.g., gold, silver, and recovery) are allowed within MicroMODEL for samples, composites, and grade models. Labels can be operated on and overwritten with the manipulation programs. There can be up to ten different model types for each grade label.

A maximum of 99 different rock types is allowed, with values ranging from 1 to 9999.

5.2 Drill Hole Limitations

There is no limit to the number of drill holes or drill hole intervals allowed by MicroMODEL with the following exceptions. The grade modeling programs allow up to 5,000,000 sample or composite drill hole intervals as input for each run. Therefore, a database can contain up to 5,000,000 intervals for each rock type. Databases larger than this can exist, but MicroMODEL is limited in processing this large database. Compositing a large database will usually reduce the data to a size within MicroMODEL's capabilities.

The compositing program has a maximum limit of 10,000 sample intervals per drillhole. In addition, a maximum of 5000 composite intervals can be created for each drillhole.

Drill holes with downhole surveys are limited to 999 downhole survey cards or records per hole.

5.3 Polygon Limitations

The point elevation (contour) files are limited to 5,000,000 total points. The pit generation polygons are limited to 20,000 points per polygon. A suggested maximum number of points per pit polygon that will be expanded is 200. This allows the pit generation programs to add points as needed.

5.4 Variogram Limitations

Variograms are limited to 36 directions per run with 25 lag intervals per variogram. A maximum of 200,000 points (drill hole intervals) can be processed within a given run.