Mining Geology and Exploration

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Mining Geology and Exploration
Mining Geology and Exploration
MMPE 290
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Plate Tectonics and mineral deposition.
MMPE 290
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Mining Geology and Exploration

• How much metal is available?
• What is a mineral? What is ore?
• How do ore deposits form?
• Mining exploration methods
• Role of exploration in mining
• Case histories

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Economically Important Metal Concentrations in
Earths Crust
Note for comparison Silicon 28 Oxygen 46
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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)
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What is an orebody?
An occurrence of minerals or metals in
sufficiently high concentration to be profitable
to mine and process using current technology and
under current economic conditions.
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What is ore grade?
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)

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Economically Important Metals Typical
Ore Deposit Average Grades
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What does it take to be an ore deposit?
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Hydrothermal Ore Deposits
As magma cools, more abundant metals (silicon,
aluminum) deposit first Solidification of magma
releases water - a hydrothermal solution Minerals
precipitate from hydrothermal solution and
deposit in cracks or veins in rock
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Metamorphic Ore Deposits
Concentration of minerals caused by high
temperatures and pressures near
intrusions Examples Lead-zinc deposits in
southeast B.C. Diamonds Garnets
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Hydrothermal and Metamorphic Ore Deposits
zoning
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Sedimentary Ore Deposits
Deposition of dense, resistant minerals in
streams, lakes etc (Alluvial Deposits),
e.g. Placer gold Precipitation of minerals from
lakes-oceans (Evaporite Deposits), e.g. Potash
and Salt Deposits Accumulation, burial and
petrification of vegetation, e.g. Coal Deposits.
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Exploration Methods

• Remote sensing
• Geological mapping
• Geophysical surveys
• Geochemical surveys
• Bulk sampling
• Drilling (core or destructive)

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Airborne Geophysics
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GEOPHYSICAL METHODS
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Geochemical Anomalies