A project to develop a computer modelling system for orebody
formation is yield- ing results beyond expectation, and these are
tearing away at the enigmatic face of mineralisation.
These discoveries are being made at Rhodes University, where the
project is headed by Professor Alan Rice, a physicist, and
Professor John Moore, an economic geologist.
The project started three-and-a-half years ago and is funded by the
Technology and Human Resources for Industry Programme and the
private sector to the tune of R600 000 a year.
The modelling system is being developed to assist in exploration
efforts and results from the project to date indicate that it will
be a useful tool, as information provided by the modelling system
would, among things, cut some of the high exploration drilling
costs.
Thisbeach sand mining equipment for sale, the first three-dimensional computer modelling system for
hard rock in the world, was inspired by the success of modelling
systems for oil reserves by the petroleum industry to determine the
movement of oil in rock.
In the hard-rock modelling system, the aim is to determine the
distribution of mineralisation in the rock surrounding a magma
(molten rock) chamber as well as the final mineralisation in the
chamber.
This information is achieved with the use of a computer code, which
is being developed usisilver ore process equipmentng several commercial codes.
Specifications such as geometry, rock permeabilities, temperatures
and fracture zones in the area of exploration are introduced to
this code, which interprets these details and predicts the location
and quantities of minerals.
“For the first time variable viscosity magma, solidification
at the walls, the coupling of hydrothermal circulation in country
rock to the cooling history of magma chamber are included in a
single modelling system,” enthuses Rice.
He adds that it irock crushing equipments south africas also the first magma convection model that is
truly turbulent.
A number of potential explanations for mineralisation, previously
not understood, have been discovered during the development of the
system.
These include the formation of spirals within highly viscous
slow-flowing magma chambers such as granites, which could only be
picked up in a three-dimensional model.
Furthermore, it has been found that in less viscous (more basaltic)
magmas the tendency is not to spiral upward, but risgold processing machines lateste at the centre
and sink at the sides.
Crystals are suspended at the bottom of the chamber as a result of
magma convection – this process is repeated, explaining
mineralisation in a stack of layers with the richest layer at the
bottom as it is the first to freeze out.
Another interesting discovery is the response of groundwater
– which carries chemistry – to and from the magma
chamber.
The chamber heats surrounding rock, causing water in this rock to
start circulating and the pattern of circulatgravity separation coal processingion explains mineral
deposits from groundwater.
Aspects such as fracture zones and geometry of the magma chamber
exercise significant control over groundwater flow.
An important discovery is the groundwater flow around a purely
spherical chamber – in this scenario, the water would pick
some random course and run off.
“Exploration drilling could completely miss this course,
leading explorers to think that there is no mineralisation apart
from that in the chamber,” comments Rice.
A greater understanding of groundwater patterns has also helped to
explain horizontal layers that never reach the surface.
The modelling system is expected to be complete in a year to 18
months and it will be compatible with most computer systems used in
the mining industry.
A business unit will be established to render a computer modelling
service.
As Rice says, it would take more than a year to learn and interpret
the code and do so effectively.
Rice says that using the modelling system could reduce the number
of exploration holes that have to be drilled.
Depending on the conditions and depth, one hole could cost up to
R1-million and, not having to drill this hole, the service would
pay for itself. A better knowledge and understanding of the orebody
provided by the system reduces the risk of incorrect mine
infrastructure development.
Commercial partners in the project include Anglo American,
Billiton, BHP and FalconBridge. Others are expected to join
soon.
The partners are to decide on a location for the first prototype
geological unit for testing of the system this month.