Chronos not Happy with Excel 'Sort' Function | Mining University

Chronos not Happy with Excel 'Sort' Function

I just got done re-building my Chronos workbook. It's not the most fun I've ever had especially on a Friday afternoon, but it had to be done.

I wanted to leave the scheduler running over the weekend with a Life of Mine scenario but this morning I noticed that the scheduled blocks weren't honoring my precedences. No matter what I did Chronos would still schedule blocks that had no business being mined. Benches from the middle of the last pushback shouldn't wind up in the first period unless there is something very wrong. Even an underground mine wouldn't have made it to these blocks in the first year of the schedule.

Chronos CPLEX optimizer
Chronos CPLEX Optimizer running in the t-shell.
I tried everything I could think of but nothing worked.

Finally, I decided that I would have to re-build the workbook.

As I was attempting to exactly follow the steps I had used to create the first workbook I realized that I had sorted the Reserve sheet. Could this be the problem? I decided to find out.

I re-sorted the Reserve sheet and checked to see that the blocks were in their original location. Easy as pie. Then I unscheduled the workbook so that I could try out the precedences again. This went awry. As Chronos attempted to un-schedule the blocks different ones were updated. Now it was obvious that sorting the workbook was creating problems. It looks like Chronos has a record of where it thinks the blocks are and it expects the blocks to always be in that order.

I eventually got the original workbook unscheduled and then re-sorted but the problem didn't go away. I'm not totally sure that you can re-sort the Reserve sheet but I do know that I will never use the sort function here again.

Sort may not have been the only problem with my workbook but it certainly didn't help. After I finished re-building the unsorted workbook everything worked fine.

Moral of the story? DON'T SORT THE CHRONOS RESERVE SHEET!!!

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