Overview

This section describes the options under the Section Resources submenu. The Section Resources module shouldonlybe used for the calculation ofresources. The Block module, in conjunction with solid and surface triangulations of the ore body outline, should be used for the calculation of reserves.

Using the Section Resources module for reserve calculations could result in incorrect figures since the ore body geometry and shape are not truly represented by the polygonal method in use by the Section Resources module.

Prerequisites

• A compositing application file ( < projname. ) must exist in order to run section resources. The compositing method should be geology, but with geology breakdown switched off. The Section Resources module reads the assay fields from this file. Also, make sure that no boundary information (for example triangulations) is included in the . cm1 file.
• Features must be set up before digitising contacts as feature codes are used to define the different contact zone types. Refer to the Design > Feature Edit submenu).
• Drillholes must be loaded (i.e. displayed on screen) to calculate reserves. See the Geology > Drilling > Load options.
• Polygonal zones must exist and be labelled with the correct zone code.
• A Section Resources Parameters file ( < proj. ), which contains geological zone codes and densities, must exist in your current working directory. This file can be created through using a text editor. See Appendix A for an example.

Algorithmic specifics

• A drillhole must pass entirely through a polygon for it to be used to create an area of influence ( AOFI) polygon.
• If the polygon is in a horse-shoe shape or encloses another polygon completely, and a drill hole passes through one part of the polygon completely but not the other, then it must be split into two polygons horizontally to get the correct results.
• The section resources process may report polygons with very small areas. This occurs when the original contacts overlap. Because the areas are so small, they may not have drillholes passing through them.
• The length of the composite is measured as the length of the drillhole segment through the triangulation (formed by projecting the AOFI polygon half to the next section) not the length of the segment in section view.
• Crossing drillholes are only handled in the Polygon Reserves option.
• When creating sections in a half moon, be aware that the direction of section creation has an effect on resulting AOFI triangulations. This is because the order of the sections is determined from the starting coordinate.
• Beware of holes that look like they are in section, but do not cross the entire polygon inside the section.
• The midplanes of the polygons must not double back on themselves (one drillhole segment per zone).Diagram - One Drillhole Segment per Zone (Section View)
• The AOFI resources calculation takes each pair of holes and generates the
• Tonnages are calculated using projected midplanes.
• Grades are weighted by density.