Minerals and Ore Grades Quiz

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Questions and Answers

Which code is used in South Africa for the reporting of Exploration Results?

SAMREC (correct)

OERN

JORC

SME

What is a defining characteristic of a mineral?

Variable chemical composition

Amorphous structure

Organic composition

Homogeneous solid (correct)

Which statement correctly describes a rock?

A rock is an inorganic liquid.

A rock is an aggregate of mineral particles. (correct)

A rock is a single mineral type.

A rock cannot contain any minerals.

What does the acronym UMREK represent?

Turkey – Uniform Mineral Reporting Code Signup and view all the answers

Which of the following best describes a mineral based on its internal structure?

Ordered internal structure (Crystalline) Signup and view all the answers

What differentiates a Mineral Resource from an Ore Reserve?

Ore Reserves include allowances for losses during mining. Signup and view all the answers

What characteristics must a Mineral Resource possess?

It must provide reasonable prospects for eventual economic extraction. Signup and view all the answers

What is included in the definition of an Ore Reserve?

The economically mineable part of the Mineral Resource, including diluting materials. Signup and view all the answers

According to the proposed PMRC 2020 edition, what study is necessary to define a Mineral Reserve?

Pre-feasibility or Feasibility studies. Signup and view all the answers

Which of the following statements is true regarding diluting materials?

Diluting materials are included in both Mineral Resources and Ore Reserves assessments. Signup and view all the answers

What is considered a low-grade copper ore in open pit mining?

0–0.5% copper Signup and view all the answers

How is high-grade silver ore defined for underground mining?

Over 150 g/t silver Signup and view all the answers

What percentage defines average grade gold ore in open pit mining?

0.5–1.5 g/t gold Signup and view all the answers

Which grade of gold is considered low in underground mining?

0–5.0 g/t gold Signup and view all the answers

Which of the following represents an average grade of silver ore in an underground setting?

150–350 g/t silver Signup and view all the answers

What defines high-grade copper ore for open pit mining?

Over 1.0% copper Signup and view all the answers

How is recovery percentage defined in mining?

Percentage of initial material extracted Signup and view all the answers

What is the low-grade classification for silver in open pit mining?

0–30 g/t silver Signup and view all the answers

What is required for a mineral resource to be classified as 'Inferred'?

Limited geological evidence and sampling Signup and view all the answers

How does an 'Indicated' mineral resource differ from an 'Inferred' resource?

It allows for mine planning and economic viability evaluation Signup and view all the answers

What does a 'Measured' mineral resource imply?

High confidence in applying modifying factors for mine planning Signup and view all the answers

What is a 'Probable' mineral reserve defined as?

Economically mineable part of an Indicated resource Signup and view all the answers

What distinguishes a 'Proved' mineral reserve from a 'Probable' reserve?

Proved reserves have greater confidence in economic viability Signup and view all the answers

Which factor is critical for the confidence level of a 'Measured' resource?

Geological consistency and characteristics Signup and view all the answers

What does the application of 'Modifying Factors' support?

Detailed mine planning and economic evaluations Signup and view all the answers

Which statement is true about the classification of mineral reserves?

Classification requires ongoing evaluation and upgrading Signup and view all the answers

What is the Gross Value of the copper ore body that averages 0.60% by weight Cu with an overall recovery of 92% and a selling price of $4.2/lb?

$46.368/ton Signup and view all the answers

What is the unit profit per ton from mining and processing the copper ore body?

$39.568/ton Signup and view all the answers

If the overall cost of mining and processing the copper ore body is $6.80/ton, what is the relationship between Gross Value and Cost?

Gross Value must be higher than Cost Signup and view all the answers

How do you calculate Profit based on Gross Value and Cost?

Profit = Gross Value - Cost Signup and view all the answers

What is the total revenue generated by the mine if it operates at a daily tonnage of 30,000 tons with a Gross Value of $46.368 per ton?

$1,390,040 Signup and view all the answers

Study Notes

Mineral Definition

Naturally occurring, inorganic, homogenous solid with a definite chemical composition and ordered internal structure (Crystalline)
Rock: Any naturally formed aggregate of one or more types of mineral particles

Rules Of Thumb Grades Of Ore

Gold
- Low grade: 0–0.5 g/t (Open Pit), 0–5.0 g/t (Underground)
- Average grade: 0.5–1.5 g/t (Open Pit), 5.0–8.0 g/t (Underground)
- High grade: over 1.5 g/t (Open Pit), over 8.0 g/t (Underground)
Silver
- Low grade: 0–30 g/t (Open Pit), 0–150 g/t (Underground)
- Average grade: 30–150 g/t (Open Pit), 150–350 g/t (Underground)
- High grade: over 150 g/t (Open Pit), over 350 g/t (Underground)
Copper
- Low grade: 0–0.5% (Open Pit), 0–1.0% (Underground)
- Average grade: 0.5–1.0% (Open Pit), 1.0– 3.0% (Underground)
- High grade: over 1.0% (Open Pit), over 3.0% (Underground)

Tonnage Definition

Expression of the amount of material of interest irrespective of the units of measurement

Recovery Definition

Percentage of material of initial interest that is extracted during mining and/or processing
A measure of mining or processing efficiency

Mineral Resource vs Ore Reserve (PMRC 2007)

Mineral Resource: a concentration or occurrence of material of intrinsic economic interest in or on the Earth’s crust in such form, quality and quantity that there are reasonable prospects for eventual economic extraction
Ore Reserve: economically mineable part of a Measured and/or Indicated Mineral Resource; includes diluting materials and allowances for losses, which may occur when the material is mined.

Mineral Resource vs Mineral* Reserve (PMRC 2020)

Mineral Resource: a concentration or occurrence of solid material of intrinsic economic interest in or on the Earth’s crust in such form, grade (or quality) and quantity that there are reasonable prospects for eventual economic extraction
Mineral Reserve*: economically mineable part of a Measured and/or Indicated Mineral Resource; includes diluting materials and allowances for losses, which may occur when the material is mined or extracted and is defined by Pre-feasibility or Feasibility studies

Mineral Resource Categories (PMRC 2020)

Inferred: quantity & grade are estimated on the basis of limited geological evidence and sampling
Indicated: densities, shape, and physical characteristics are estimated with sufficient confidence to allow the application of Modifying Factors to support mine planning and economic viability evaluation
Measured: densities, shape, and physical characteristics are estimated with confidence sufficient to allow the application of Modifying Factors to support detailed mine planning and final economic viability evaluation

Ore Reserve Categories (PMRC 2007)

Probable: economically mineable part of an Indicated, and in some circumstances, a Measured Mineral Resource
Proved: economically mineable part of a Measured Mineral Resource

Mineral* Reserve Categories (PMRC 2020)

Probable: economically mineable part of an Indicated, and in some circumstances, a Measured Mineral Resource
Proved: economically mineable part of a Measured Mineral Resource. It implies TECHNICAL STUDIES

Gross Value And Profit Calculations

Gross Value = Grade (% or g/MT) x Recovery (%) x Price ($)
Profit = Gross Value – Cost
Example: Estimate the unit profit in $/ton of mining and processing a copper ore body averaging 0.60% by weight Cu if the selling price of copper in the concentrate is $4.2/lb, assuming that the overall cost of mining and processing is $6.80/ton. Overall recovery, based on metallurgical engineering is expected to be 92% of the copper.
- Gross Value = 0.006 x 0.92 x $4.2/lb x 2000lbs/ton = $ 46.368/ton
- Profit = $46.368/ton - $6.80/ton = $ 39.568/ton

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Description

Test your knowledge on the definitions of minerals and the grading of ore types including gold, silver, and copper. Understand the classifications of low, average, and high-grade ores based on their content. Perfect for geology enthusiasts and students.