CECS — Mining & Mineral Processing
You can't estimate a mine you don't yet understand underground. In mining, maturity depends not only on engineering but on how well the resource itself is defined — so the classes align with the industry's scoping → pre-feasibility → feasibility study stages. Built on AACE 47R-11.
What this standard adds
The framework is the same five classes from Lesson 1, but mining adds a second axis of definition that no other industry has front-and-center: the resource itself. You can have detailed plant engineering, but if the ore body is poorly defined, your overall estimate is still immature — because the thing being mined is uncertain.
Why mining & mineral processing differs
- The resource is an input — Grade, tonnage, and metallurgical recovery come from drilling and testwork — and they drive the whole business case, not just the cost.
- Huge earthworks & infrastructure — Open pits, waste dumps, tailings storage, and often remote roads, power, and camps dominate cost alongside the process plant.
- The processing flowsheet — The mineral processing flowsheet (crush, grind, separate, recover) is the plant's backbone deliverable — analogous to a process PFD.
- Remote, site-specific risk — Location, logistics, and ground conditions create large, project-specific uncertainty that early estimates must carry as contingency.
Study stages mapped to classes
Mining has its own well-known study terminology, which maps onto the estimate classes (general pattern; the RP and resource codes give the authoritative detail):
| Class | Study stage | Resource confidence |
|---|---|---|
| 5 | Conceptual / scoping study | Inferred (low) |
| 4 | Pre-feasibility study (PFS) | Indicated |
| 3 | Feasibility study (FS / bankable) | Measured & indicated |
| 2 | Detailed engineering | Measured |
| 1 | Detailed engineering / control | Measured |
Putting it to work
For a mining estimator, the class is a statement about both the study stage and the resource confidence behind it. State them together, ensure the engineering and the geology have matured in step, and carry honest contingency for the remote, site-specific risks that mining projects always face early on.
Nine things to remember
- 47R-11 applies the five-class system to mining — engineering plus resource confidence.
- Mining matures on two axes — resource (inferred→measured) and engineering.
- The class reflects the weaker axis — great plant design + inferred ore = still immature.
- The resource is an input — grade, tonnage, and recovery drive cost and revenue.
- Metallurgical testwork is pivotal — it sets recovery, throughput, and viability.
- Earthworks, tailings, and remote infrastructure are major cost drivers.
- Classes align with study stages — scoping (5), PFS (4), feasibility (3).
- "Bankable" feasibility (≈ Class 3) is a precise, regulated bar — don't overstate it.
- One framework, many dialects — mining adds the resource axis to the same logic.
Glossary
- Feasibility study (FS)
- "Bankable" study; ≈ Class 3.
- Flowsheet
- The mineral processing process diagram — a key deliverable.
- Inferred / indicated / measured
- Rising levels of geological confidence in a resource.
- Metallurgical testwork
- Tests establishing recovery and processing behavior.
- Mineral resource
- An estimated concentration of minerals with reasonable extraction prospects.
- Pre-feasibility study (PFS)
- Intermediate study; ≈ Class 4.
- Scoping study
- Earliest economic study; ≈ Class 5.
- Tailings storage
- Facility for processing residue — a major cost item.