Evaluate Stope Polygon

You can use this function to help you create a practical stope from a block model, or from an existing solid of an ore body. This function projects a closed polygon outwards across the corridor of a plane in the Away direction, and in the Towards direction. If there is a block model in the same location, this function can output the grade, mass, and contained metal within the projected solid. If you edit the points of the polygon and then run this function again, you can quickly the change in grade, volume, or other properties of the proposed stope.

Note: The projection direction of the polygon is perpendicular to the plane unless a Dip and Dip direction is set in the stope design project. If the Dip and Dip direction are set, they determine the projection direction. A positive Dip makes the projection slope upwards from a position perpendicular to the plane. A negative Dip makes the projection slope downwards. The Dip direction value is the number of degrees of rotation of the slope, starting from the top of the screen in a clockwise direction.

Prerequisites: A plane is active. There is a single closed polygon in the active plane. You have run INIT STOPE to start stope design.

To run this function: Choose Design > Stope Design tools > Evaluate polygon, or...

• In the Function Chooser, type EVALUATE STOPE POLYGON, and press ENTER.

Fields on the Evaluate stope polygon form

Field	Description
Plane name	The name of the plane that is active.
Away	The distance from the active plane away from the camera.. The width of the plane is the Away distance plus the Towards distance. The stope you create is projected across the width of the plane.
Towards	The distance from the active plane towards the camera.
Property	The Property table shows the values of the properties within the stope, including: Polygon Volume. The volume of the projected solid that you are evaluating. Polygon Area. The area of the polygon projected onto the plane. Polygon Mass. Polygon Mass is generated only when no block model is used and the specific gravity is set to a single specific value. Any attributes that you selected on the Block Model tab when you started or edited the stope design project, are also shown. If you selected a grade attribute, several derived properties such as mass and metal are also shown. Note: Metal = mass x grade. However, the grade value that you see in the Evaluate Stope Polygon form might be rounded to a smaller number of decimal places than the grade that the system used to calculate the metal value. For example, if the grade attribute in the block model is set to have 2 decimal places, the Evaluate Stope Polygon form will show grade with no more than 2 decimal places, such as 2.27. However the average grade of the blocks within the stope, which is the grade value used by the metal calculation, might be a number with more than two decimal places, for example 2.2673.

Output

After you run EVALUATE STOPE POLYGON, the Evaluate Stope Polygon form reports details of the stope including grade, mass, volume, and contained metal. After you click Apply, a temporary solid representing the stope is displayed in Graphics in a layer called <working layer>_evaluation_solids.

Tip: To hide the temporary solid, in the Planes panel click Draw triangulations as triangles or polygons.

See also

• Start Stope Design