Pit Optimization Settings: Ultimate Pit

To access this dialog:

Using the Optimization control bar, select Ultimate Pit | Settings and select the Ultimate Pit tab.

For a more detailed explanation of the slope definition process, see Pit Optimization.

Field Details:

Maximize cash flow: select to conduct a Lerchs-Grossmann (LG) search for the ultimate pit maximizing cash yield.

Use underground processing option: select if you have defined an underground processing method and LG optimization is to account for the underground mining alternative.
Use top-down bench discounting: select if LG optimization is to use discounted block values, entering an Average sinking rate, expressed in benches per year. Based on the sinking rate, the Discount rate is calculated automatically and displayed below as a % per bench. This accounts for the fact that blocks located deeper in the deposit tend to be mined later and thus contribute less to NPV.

By default block values are discounted from the top elevation of the initial topography. Block discounting can also start from a user defined bench (elevation). With this option, the value of the blocks above that bench are not discounted.

Change... used to define the bench to be used for discounting of block values. Clicking Change... displays the Start Discounting at Bench dialog.

Maximize resources: select to optimize but retaining all ore (raw material) which usually will be larger than the cash maximizing pit. In this context, it is the slopes that are being optimized. The Maximum Resource pit includes only ore (raw material) blocks with positive net value.

Use pit shell selected from the list below: skips the ultimate pit search part of pit optimization and instead use a pre-existing pit shell.

Select the Indicator file defining the desired surface from the provided list and enter the Surface Pit Code (the indicator value identifying the surface within the file). This option is used when importing a designed pit from an external application such as Studio 3 (in this situation, you would run the ultimate pit optimization to generate the ultimate pit optimal extractions sequence (UP OES) within the design pit before optimizing pushback generation).

If this option is selected, the resulting Pit Optimization Summary report will contain statistics related to the ultimate pit generated with the supplied surface, in addition to the existing 'final pit' statistics. Also, if this option is selected, the generated LG Phases report will optimal pit report items in a red font.

Limit OES to the last LG Phase: this check box allows you to constrain ultimate pit with property surface (water table, geotechnical surface, etc.). When the check box is selected the blocks that are outside the last LG shell and above the surface are not added to the ultimate pit OES.

Recalculate Optimal Extraction Sequence: skips the LG shell search part of pit optimization when OES search is based on "Lookahead Values". If you change the bench value (ex. from 6 to 10) when this option is selected, NPV scheduler will use the same LG shells and recalculate the OES using a search cone with the benches specified under the Pit Optimization Settings Sequencing tab.

	Related Topics
	Pit Optimization Essentials Pit Optimization Quick Star Start Discounting at Bench

JMN 20065_01_EN