MineLib: zuck_large
The same test on a second deposit
Published mine plans model the geology in detail and the operation barely at all. A solution can be close to the best available answer to the model it was given, and still describe something a site could not physically do.
These benchmarks test that. We take a published solution, require it to obey the physical constraints a real operation works under, and see what its value does. We then run the same deposit through Cognomine, where those constraints are inside the problem from the start.
We have done this on two deposits. On one the published solution lost 58.4% of its stated value. On the other, 29.5%. A plan built without physical constraints was not designed to survive them or to fail them, so how it fares once they are applied is essentially random. Nothing in the reported NPV tells a planner which case they are looking at.
What we tested
zuck_large is a MineLib PCPSP instance of 96,821 blocks. Unlike McLaughlin it carries two explicit resource constraints in its own descriptor: C0 mining capacity at 3,000,000 tonnes per period and C1 processing capacity at 1,200,000 tonnes per period. Both are genuinely modelled and respected by the published solution.
The instance economics and the 10% discount rate are the library's own and unchanged. The source data is normalised to net value rather than carrying separate price and cost components, so metal price is $1 per unit, mining cost $1 per tonne, processing is nil because it is already inside the metal price, and recovery is 1.0. Every figure on this page is in those normalised units, not in real currency.
Beyond those two resource constraints, the model is as sparse as McLaughlin's. Of the ten constraint families a real operation works under, it models two.
What the published model leaves out
| Constraint family | Status | What the model does |
|---|---|---|
| Mining (C0) capacity | Modelled | 3,000,000 tonnes per period, genuinely modelled and respected |
| Plant feed (C1) capacity | Modelled | 1,200,000 tonnes per period, genuinely modelled and respected |
| Active dig-face separation | Not modelled | No fleet or equipment model exists, so any number of faces can be worked at once |
| Equipment operating-hour budget | Not modelled | No diggers, trucks or operating-hour budget appear in the model |
| Fleet purchase capital | Not modelled | No fleet ownership or purchase-cost term, so early mining spikes get their extra fleet for free |
| Haulage destination allocation | Not modelled | Two abstract destinations, with no route, haul-distance or trucking-cost model |
| Waste destination capacity | Not modelled | No waste dump capacity term, so waste is discarded with no destination limit |
| Monthly production timing | Not modelled | The finest time unit is a full period, so pacing within a period is unconstrained |
| Drill-and-blast prep time | Not modelled | No blast-to-dig window, so a bench can be re-entered the same period blasting finishes |
| Undermining stability guard | Not modelled | A block may be scheduled while material on the bench directly above and beside it is still standing |
Results
MineLib PCPSP (fair scored replay)
Legalised indicative replay
- NPV (monthly discounted, with fleet capex)
- $40,443,837
- Undiscounted cashflow
- $115,405,222
Our solution
Constrained production run
- NPV
- $40,768,329
- Undiscounted cashflow
- $97,436,796
- NPV vs fair scored replay
- +$324,491
- % of fair scored replay
- 100.8%
All figures on this page are in the instance's normalised value units, not real currency.
The published solution scores $57,334,014. Required to obey the same six constraint families and the same rules used on McLaughlin, the same schedule is worth $40,443,837. 29.5% of the stated value does not survive, against 58.4% on McLaughlin.
Against the constrained comparator, the Cognomine plan carries $324,491 more NPV, at 100.8%. On this deposit the two are close to level.
We publish that result as it stands. A plan built without physical constraints was not designed to survive them or to fail them, so how it fares once they are applied is essentially random. On McLaughlin it fared badly. Here it happened to fare well, and a plan that ends up close to executable by chance is still a plan nobody could have relied on in advance.
What this benchmark does not show
- Constraints are deliberately not identical. That is the point of the comparison. The published solution was produced against a model with no fleet, haulage, drill-and-blast timing or capital. This is not a like-for-like contest between two solvers on the same problem.
- The replay is our construction. We defined the rules by which the published schedule is made physically legal. Those rules are set out in the methodology note.
- The replay inherits the published block selection. It is made to obey the physical constraints but cannot re-choose what to mine, because the published formulation has no way to express fleet, haulage or drill-and-blast timing and so cannot be re-solved under them.
- The problem definitions differ. The published formulation cannot represent a stockpile. Cognomine can. The stockpile in this run is finite, at 5 million tonnes, and operates strictly first in, first out. Material cannot be held back and retrieved out of order to favour grade.
- This benchmark makes no speed claim. No runtime was published for the comparator, so there is nothing to measure against. Speed results are on the strategic planning benchmark.
- This run sits within normal production limits. At 96,821 blocks this deposit was solved at full resolution with no reblocking. Standard fidelity handles up to 100,000 scheduling units, High Fidelity up to 500,000. How reblocking and High Fidelity work
- One deposit is one deposit. The same method on McLaughlin produced a very different result. See that benchmark
Run it on your own numbers
Sources: MineLib PCPSP instance zuck_large and its best-known published solution, retrieved from minelib.org on 9 September 2026. The library is described in Espinoza, D., Goycoolea, M., Moreno, E. and Newman, A. (2013), "MineLib: a library of open pit mining problems", Annals of Operations Research 206(1), 93 to 114, doi:10.1007/s10479-012-1258-3. Cognomine results are our own. Method in the methodology note.