---
title: "Reserve versus resource"
subject: "Engineering Geology II"
chapter: 7
key: "semester_4/engineering_geology_ii:reserve-vs-resource"
source: https://www.bctengineer.com/q/semester_4/engineering_geology_ii/reserve-vs-resource
site: BCT Engineering
---

# Reserve versus resource

Engineering Geology II · Chapter 7: Geology and Construction Materials

- Asked in: 2075 Bhadra, 2 marks; 2076 Baisakh, 1 marks; 2078 Poush (asked 3 times)
- Video: [Resource and Reserve](https://www.youtube.com/watch?v=Tyn-5FbHaYA) — Geology Aspirant
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_4/engineering_geology_ii/reserve-vs-resource
- Whole chapter: https://www.bctengineer.com/md/semester_4/engineering_geology_ii/chapter-7

## Question

What is a resource? Differentiate between reserve and resource, and between total resource and undiscovered resource.

## Short answer

A resource is the total natural concentration of material potentially feasible for economic extraction. A reserve is the identified, economically extractable subset of a resource. Total resource includes both identified and undiscovered material, while undiscovered resource comprises only hypothetical and speculative material not yet found.

## Answer

#### Resource
A **resource** is the total concentration of naturally occurring material (rock, sand, minerals, fuels) in or on the earth's crust in such form and quantity that its economic extraction is currently or potentially feasible. It includes both discovered and undiscovered material.

#### Reserve versus resource
| Basis | Reserve | Resource |
|---|---|---|
| Meaning | Identified material that can be extracted economically and legally now | Total occurrence, including material not yet economic or not yet discovered |
| Certainty | Well known (measured and indicated) | Known to unknown |
| Economic viability | Viable at present | Viable now or in the future |
| Size | Smaller | Larger (a reserve is part of a resource) |
| Change | Changes with price and technology | Changes slowly with new discoveries |
| Example | Quarry sandstone with an approved volume | All the sandstone in the formation |

#### Total resource versus undiscovered resource
| Basis | Total resource | Undiscovered resource |
|---|---|---|
| Meaning | Identified + undiscovered | Only material not yet found, but expected to exist |
| Parts | Demonstrated (measured + indicated), inferred, hypothetical and speculative | Hypothetical (in known districts) and speculative (in unknown districts) |
| Basis of knowledge | Evidence and assumption | Geological inference only |

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. What is a resource?
   A. Only material extractable profitably today
   B. The total occurrence of material, discovered or undiscovered, whose extraction is currently or potentially feasible
   C. Only material already measured by drilling
   D. Only undiscovered material
   Answer: B. Resource includes everything that may become economic, known or unknown. (Key point: Resource definition)

2. Which statement is correct?
   A. Reserve is larger and contains resource
   B. They are identical terms
   C. Resource is always measured; reserve is speculative
   D. Reserve is smaller and is a part of resource; it changes with price and technology
   Answer: D. Reserve is the identified, economically viable part of the resource. (Key point: Reserve vs resource)

3. What does undiscovered resource consist of?
   A. Measured and indicated resources
   B. Hypothetical (known districts) and speculative (unknown districts) resources
   C. Only inferred resources
   D. Reserves under approved quarries
   Answer: B. Total resource includes identified plus undiscovered; the undiscovered part is hypothetical plus speculative. (Key point: Undiscovered resource)

## Related in Engineering Geology II

- [Rock mass versus intact rock](https://www.bctengineer.com/question.md?key=semester_4%2Fengineering_geology_ii%3Arock-mass-vs-intact-rock) — Engineering Geology II, chapter 6, asked 7×
- [Hazard versus risk](https://www.bctengineer.com/question.md?key=semester_4%2Fengineering_geology_ii%3Ahazard-vs-risk) — Engineering Geology II, chapter 5, asked 6×
- [Confined versus unconfined aquifer](https://www.bctengineer.com/question.md?key=semester_4%2Fengineering_geology_ii%3Aconfined-unconfined-aquifer) — Engineering Geology II, chapter 3, asked 4×
- [Surface versus sub-surface investigation](https://www.bctengineer.com/question.md?key=semester_4%2Fengineering_geology_ii%3Asurface-vs-subsurface-investigation) — Engineering Geology II, chapter 4, asked 3×
- [GLOF versus LDOF](https://www.bctengineer.com/question.md?key=semester_4%2Fengineering_geology_ii%3Aglof-vs-ldof) — Engineering Geology II, chapter 5, asked 3×
- [Aquifer versus confining bed](https://www.bctengineer.com/question.md?key=semester_4%2Fengineering_geology_ii%3Aaquifer-vs-confining-bed) — Engineering Geology II, chapter 3, asked 2×

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