Mining Geology

INTRODUCTION
But as for us, though we
may not have perfected
the whole art of the
discovery and
preparation of metals, at
least we can be of great
assistance to persons
studious in its
acquisitions
- AGRICOLA De Re Metallica, 1550
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 SYLLABUS
• Introduction to Exploration and Mining Geology – Mineral Discoveries
• The Global Mining Business and Mineral Economics
• Historical Perspective of Global and Philippine Mining Industry
• Mineral Deposit Types in the Philippines
• The Mining Cycle, Greenfields vs. Brownfields
• Philippine Mining Operations
1.Overview of Mineral Deposits and Mining
2.Metallic mines
3.Non-Metallic Mines
4.Coal mines
5.Quarries
• Exploration, Feasibility and Mine Development
1.Stages of Mineral Exploration
2.Mineral Exploration Methods
1.Prospecting/ Remote Sensing
2.Exploration Geochemistry
3.Exploration Geophysics
4.Geologic Mapping
5.Drilling and Core Logging
6.Sampling and Assaying
7.Computer Methods
8.Reporting of Exploration Results and Mineral Resources
3.Feasibility, Financing and Mine Development

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 SYLLABUS
• Mining Methods and Procedures
1.Mining Methods
1.Small-Scale Mining
2.Large-Scale Mining Operation
1.Underground Mining
2.Surface Mining
3.Other Mining Operations
2.Mineral Processing (Beneficiation), Smelting & Refining

• Geology in Mining Operations

1.Mine Exploration
2.Mine Geological Mapping
3.Mine Drilling
4.Grade Control and Reconciliation
5.Geometallurgy
6.Geotechnical work
7.Reporting of Ore Reserves

• Philippine Mineral Reporting Code (PMRC)

• Mining tenements
• Mine Safety, Social Responsibility & Environmental Care

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 What is Mining ?

Mining is the extraction of valuable raw metallic and

non-metallic materials or other geological materials
from the earth

anything that cannot be grown or created unnaturally in a

laboratory or factory, is usually mined

base metals, precious metals, iron, clay, mineral sands, coal,

limestone for cement, construction aggregates (quarrying), and
elements such as sulphur, diamonds and gold

mining is a non-renewable resource industry

modern mining involves 4 stages :- searching for ore bodies (exploration) ,

analysis of the profit possible of a proposed mine (feasibility), removal of
the desired resources (mining and milling) and finally retrieval of the land
to get ready it for other uses once the mine is closed (decommissioning)

Mining was the second of man’s endeavors — agriculture was the first
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 Why do we need mines ?

Every Average Human Being will need ...

If we can’t grow it, it has to be mined ! 5

 Why do we need mines ?

Houses
Cars

Toothpaste
Plumbing
Wiring
Planes
Electronics
Jewelry
Glass
Appliances
Cellphones
……
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 What is Mining Geology?
Mining Geology is an adjunct field of Economic Geology that helps to
locate and manage the Earth's natural resources, such as petroleum and
coal, as well as mineral resources, which include metals and non-metals.

Mining geology encompasses Mineral Exploration Geology – the search

for valuable earth materials

An exploration and mining geologist learns to

practice:

(1) the techniques and discovery of new mineral

resources,

(2) understanding of the economics of mining and

processing the resource, and

(3) the social and environmental impacts of the

mining operation, including mine closure and
reclamation

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Mineral Economics & The Global Mining Industry
How much metal is available?

World Gold Resources

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Mineral Economics & The Global Mining Industry
How much metal is available?

World Copper Resources

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 Mineral Economics & The Global Mining Industry
EARTH’S RESOURCES
• Metallic

• Non-Metallic

• Energy

• Water
 Geologic Resources
Geologic resources - valuable materials of geologic
origin that can be extracted from the Earth

– Many geologic resources originate in the hydrosphere

• Petroleum and coal come from organisms that lived and died
in water
• Halite (salt) and other evaporite minerals come from dry lake
beds
– Weathering interactions between geosphere, atmosphere and
hydrosphere produce metal oxide ores

– Humans (biosphere) interact directly with the geosphere, hydrosphere,

and atmosphere when extracting and utilizing geologic resources

– Groundwater (hydrosphere) is a renewable geologic resource

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 Types of Geologic Resources

Geologic resources are grouped into three major categories:

– Energy resources - petroleum (oil and natural gas), coal,

uranium, geothermal resources

– Metals - iron, copper, aluminum, lead, zinc, gold, silver,

platinum, nickel, chromium

– Non-metallic resources - sand and gravel, limestone,

building stone, salt, sulfur, gems, gypsum, phosphates,
groundwater

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What is a mineral?
A solid naturally-occurring compound having a definite
chemical composition
Examples:
quartz - SiO2 (an oxide)
hematite - Fe2O3 (another oxide)
chalcopyrite - CuFeS (a sulphide)

What is ore?
Rocks, minerals or metals in sufficiently high concentration
to be profitable to mine and process using current
technology and under current economic conditions.

Ore grade is the concentration of economic mineral or metal in

an ore deposit.
·Weight percentage (base metals)
·Grams/tonne or oz/ton (precious metals) 13
 Mineral Resource :Basic Concepts
 Resource
 Absolute volume of a mineral commodity in existence, independent
of economics and technology

 Reserves or proven reserves

 Known quantity of a resource available (produced at a profit)
 Dependant on current economic conditions (including demand)
and extant technology

 Concentration factor
 Ratio of ore material concentration to average crustal concentration

 Mode of occurrence
 A desirable commodity must occur in a mineral form that is readily
processed to produce the commodity
 Associated, unwanted mineral material (gangue) and waste after
processing (tailings) must be considered in economic assessment
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 Mineral Resource :Basic Concepts
Gold
Distribution of Au in the crust = 3.1 ppb by weight
 3.1 units gold / 1,000,000,000 units of total crust
= 0.00000031% Au
Concentration of Au needed to be economically
viable as a deposit = few g/t  3 g / 1000kg =
3g/ 1,000,000 g = 0.00031% Au
Need to concentrate Au at least 1000-fold to be a
viable deposit
Rare mines can be up to a few percent gold
(extremely high grade)
Gold (Au) is almost 1,000,000 times less abundant than iron (Fe)
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 Mineral Resource :Basic Concepts
 Ore deposits require
 Source for metals (or other elements)
 Means of concentrating elements into usable quantities

 Types of Ore Deposits

 Magmatic (cumulate, lode, pegmatite)
 Hydrothermal (porphyry, vein, skarn,
exhalative, epigenetic)
 Sedimentary (placer, BIF, laterite, evaporite)

 Ore Minerals
 Native elements (Au, Ag, Cu, Pt, diamond, sulfur)
 Sulfides and sulfosalts (pyrite, sphalerite, chalcopyrite, galena)
 Oxides and hydroxides (magnetite, chromite, corundum, hematite,
rutile)

Ore mineral – desired metal / non-metal / element

Gangue – waste material
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 Plate Tectonics & Mineral Deposits

Geyser or hot
spring

Hydrothermal solutions
entering veins in rocks Ore deposit

Alteration of rocks by
heat and pressure

Intrusion

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 Ore Deposit Geology

Economically Important Metal Concentrations

In the Earth’s Crust

Concentration
Note for comparison:
Metal (% by weight)
Silicon 28%
Aluminum 8.0
Oxygen 47%
Iron 5.8
Copper 0.0058
Nickel 0.0072
Zinc 0.0082
Uranium 0.00016
Lead 0.001
Silver 0.000008
Gold 0.0000002

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 Ore Deposit Geology

Economically Important Metals

Typical Ore deposit Average Grades

What does it take

Typical Grade to be an ore deposit?
Metal (% by weight) 2
10
Aluminum 30 Iron
Aluminum
1
Iron 53 10

Typical Orebody Concentration

Lead Zinc
Copper
Copper 0.5-4 0
10 Nickel
Uranium
Nickel 1 -1
10
y=x

Zinc 4
-2
10 Silver
Uranium 0.3
Lead 5 -3
10
Gold
Silver 0.01 -4
10
-7 -5 -3 -1 1 3
10 10 10 10 10 10
Gold 0.0001-0.001 Crustal Concentration

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 Ore Deposit Geology

Distribution of Au in the crust = 3.1 ppb by weight 

3.1 units gold / 1,000,000,000 units of total crust =
0.00000031% Au
Concentration of Au needed to be economically
viable as a deposit = few g/t  3 g / 1000kg = 3g/
1,000,000 g = 0.00031% Au
Need to concentrate Au at least 1000-fold to be a
viable deposit
Rare mines can be up to a few percent gold
(extremely high grade)!
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 Ore Deposit Geology

 Many valuable elements are in the trace

element range, including the gold group (Au,
Ag, and Cu) and the platinum group (Pt, Pd, Ir,
Os), mercury, lead, and others

 Useage does not always reflect abundance –

copper (55 ppm) is used more than zirconium
(165 ppm) or cerium (60 ppm)

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Mining Cycle

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Exploration and Mineral Discovery

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 What is Mineral Exploration?

Mineral Exploration is the search for mineral

deposits.

It means finding or prospecting for a mineral deposit

or a “Mineral Resource” - by geological,
geochemical and/or geophysical surveys, test pitting,
trenching, drilling and other related means for the
purpose of determining their existence, quantity and
quality, and the feasibility of mining them.

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Do all exploration projects find mineral deposits ?

No, not all results from exploration surveys lead to

discovery of mineral deposits. The surveys are done
only to test, identify and assess possible economic
minerals present on and underneath the surface.

If there are not enough grades (quality) and tonnages

(quantity) in the exploration target area, it cannot
become a mineral deposit or a Mineral Resource.
Mineral Exploration is a
risky business
As a general rule, only one (1)
out of one thousand (1,000)
mineral prospects become
significant mineral deposits.
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 Do all mineral deposits become mines?

No. Even if a mineral resource is found, there

is no guarantee that it will become a mine, as
there are other factors that should be
considered for a viable mining operation –
economic, social, legal, environmental etc.

Every new mine has its beginnings as an

exploration project; however, most exploration
projects will not advance to become mines.
Mineral deposits do not
automatically become mines
Only one (1) out of a hundred
(100) mineral deposits become
mines 26
Large-scale vs. Small-scale Mining

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Responsible Mining Methods

Underground Mining

Open cast Mining

Quarrying / Strip Mining

Placer (Alluvial) Mining

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 Beneficiation
Means of separation of ore mineral from waste material (or gangue minerals)
Also known as Liberation

Crushing and Grinding

Ball mill or rod mill
Separation
Density (e.g. diamonds with a jig)
Magnetic properties
Electric properties
Surface properties
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 Refining / Smelting
Smelting - removes the metal from the ore mineral by a variety of ways

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Socio-Economic and Environmental Impacts of Mining

• Community

• Livelihood

• Economy

• Soil

• Water

• Forest

• Indigenous
Rights

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 The Philippine Mining Industry
20°

Sto. Niño Batong Buhay

Baguio Gold
Itogon


Benguet Corp. - Kelly Mines
Lepanto Consolidated - Mankayan Mine
Benguet Corp. - Chico Mines



CAGAYAN

Lepanto Consolidated - Victoria Mine

N
Benguet Corp. - Acupan Mine 0 200 400
Antamok Mines
Thanksgiving Mine
Kilometers
Black Mountain Mine Atok Big W edge Mine

Cal Horr Open Pit

Sierra Oro Mine

Philex Mining - Padcal Mine Itogon Suyoc Mine

15°
United Paragon
Mining
. Corporation
Benguet Corp. -Masinloc Mine

Benguet Corp. - Dizon Mine Atlas MGO

P
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PHHH
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Small-scale mining
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IIIIIIPPP
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Alamag
PPPIII
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NN
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Marcopper Mining Corp.

A
AA
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AUUU

Hinatuan Manicani Project

UUULLL
LLLTTT
TTT

CAP IZ
Heritage Mining

Crau Mineral
Resources Corp.
Kromico
Maricalum Mining Corp. Vel-ore 10°
Cagdianao Mining Corp.
Philex Gold - Bulawan Mine
Rio Tuba Mining Corp. South Seas Mining PHILNICO (NONOC)

Atlas Consolidated Mining Dev. Corp. Hinatuan Mining

Philex Gold - Sibutad Mine Manila Mining

Taganito Mining

Apex Mining - Masara Mine

North Davao Mining - Amacan Mine

Large-scale mining
LEGEND: 5°
Gold Deposit
Chromite Deposit
Copper Deposit
Nickel Deposit
125°
115º

120º

OPERATING MINES IN THE PHILIPPINES 32

 If we can’t grow it, it has to be mined !
References

Geological Methods in Mineral Exploration and Mining Geology

Exploration and Mining William C. Peters
Roger W. Marjoribanks
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