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Geologic and mine modelling

Orebody modelling is the stage between geological sampling (core and log data, chemical analyses…) and mine planning. The Modelling Department, integrated in the Technical Division, uses a 3D representation of the orebody: block models.






The block model concept is designed to represent a rock formation as a 3D grid of small parallelepipeds (blocks) measuring a few metres by a few tens of metres, all identical in size. The term “block model” derives from representing a reality (a model = a representation of reality) as a set of blocks. Values (such as nickel grade, density or any other relevant value) can then be attributed to each block.
This type of model has the advantage of allowing the complex geometric forms of rock formations to be treated as a sum of simple geometric objects. Similarly, it enables a simple approach to metal content distribution.

Simplifying reality in this way allows orebodies to be read and interpreted by specialised software programs, particularly useful for mine planning and operations purposes.





Use of the technique

As laterite nickel orebodies are, overall, stratiform (not very thick, elongated and sub-horizontal or inclined), several models are generally produced, each model representing a layer, or at least two models – one for the laterite and one for the saprolite layer

The most difficult part of creating a block model consists of determining a grade for each block based on grade readings from samples. This stage is known as interpolation.
There are many methods of interpolation, some simple and others far more complex. The methods rated most highly by mining companies worldwide are drawn from 1960s French research into numerical geology and form part of a field of geological research known as geostatistics.

Great skill is required to produce block models. The work is carried out by NMC teams; the Group has worked closely with specialised firms whose proven expertise in the field is recognised in mining circles worldwide.

Public limited company:
Issued capital of 394,863,200 F CFP
Ouaco, shire of Kaala Gomen in the Northern Province
Noumea office:
85, Av. du General de Gaulle, im. Carcopino 3000, Noumea
Postal address:
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(687) 28 13 53
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Date of constitution:
27 September 1979
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