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MAGNETIC TECHNIQUEDIAMOND MINING

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OBJECTIVES

To identify the location of thediamonds using magnetic technique

METHODOLOGY

• Aeromagnetic exploration•Exploration model used in exploration

for kimberlite

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 Aeromagnetic surveys

assist in mineral development

through improved geologic

mapping

-Area selection for primary diamond

deposits

-Based on a conceptual model for 

kimberlitic occurrences

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Emplacement of diamondiferous kimberlites is

controlled by three principal criteria

(1) existence of a sufficiently thicklithosphere, favourable to diamond

genesis and preservation

(2) presence of major tectonic trends

and lineaments that could act as

pathways for kimberlitic magma, theprincipal diamond-bearing lithology

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(3) the recognition of magneticanomalies related to mafic –ultramafic

intrusives, signs of deeply-rooted

magma

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How the aeromagnetic data is

interpreted????????? using energy spectral analysis

different data-enhancement filters, has

permitted elucidation of all threecriteria

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Study area

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The basic physical phenomenon thatgoverns the investigation’s of 

magnetic depth method is the Curie

temperature by which the detection of magnetic

bodies is limited by

the depth of the Curie isotherm

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It is assumed that the decreasedmagnetization

of crustal rocks at depth is due totemperatures

above the Curie point rather than todeep-seated lithologic changes, whichrequires that the depth to the bottom of 

magnetic sources be large relative to thedepth of the top,

essential to spectral separation.

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The radially averaged logarithmic power spectrum presented

in Fig. below – was computed from the entire south-west

area of Algeria

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From an exploration point of view, theestimated depth is close to the Curie

isotherm surface characteristic

of stable low heat-flow regions, whichreveals

favourable lithospheric conditions for 

diamond genesis

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OASIS montajTM Data Processing and Analysis

system (Geosoft, 2004)

Data-enhancement processes such asreduction to the pole, upward

continuation, and the shaded-relief 

imaging technique have beenperformed in order to present maps

in a form which assists human

comprehension, and hence geologic interpretation

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This simplifies the interpretation bycentring anomalies over the causative

magnetic body

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ENVIRONMENTAL

PROTECTION

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ENVIRONMENTAL

IMPACTS

ENVIRONMENTAL

PROTECTION

Energy use, air quality and pollution •installing timers on boilers•introducing battery-powered

vehicles that do not emit harmful

gases

•using solar panels

Waste and recycling •waste materials are separated into

categories at the mine to ensure

appropriate disposal and recycling

Use of water  •through reduction, recovery, reuse

and recycling

•strict targets for usage

Impact on biodiversity •the native plant life around a site is

harvested and the seeds replanted.

•runs numerous wildlife

conservation projects

•establish a number of Nature

Reserves