Bench Accumulation
The Bench Accumulation constraint is used to set the maximum amount that can be mined per bench per period. Benches are grouped in terms of stage. 
The Item drop-down menu allows you to specify the item to set the accumulation constraint against. 
You can input the value manually per each bench for each period, or copy once entered value using the  button.
 button. 
Tip!  Click  to copy the value from the current cell to the next period. Double-click
 to copy the value from the current cell to the next period. Double-click  to copy the value  to all subsequent periods.
 to copy the value  to all subsequent periods.
