GeoScience Victoria
Mineral Occurrence Data Model Scenarios
Scenario 1
Description: an explorer conducts an investigation of mineralisation over an
exploration lease
Carol is an exploration geologist for a medium-sized multi-commodity explorer in
eastern Australia. She is investigating the potential for gold mineralisation under
cover to the north of known gold occurrences, as well as any opportunities for the
company to earn additional income from secondary commodities in their area of
interest.
She reviews the previous work related to the tenements her company has just acquired
over a large area in Victoria and NSW. She searches for known mineral occurrences
on the tenements, the past operators of the workings and the reasons for tenement
relinquishment. Most of the information she has accessed is from exploration licence
and other similar reports, but there are also a few university theses describing various
aspects of the geology. The information she finds includes:

details about the mineral occurrences, their characteristics, and their
association with structures and host rocks;

historic plans of workings

3D models of workings and deposit geology and mineralisation

data pertaining to metallurgy; and

production statistics, including average grades and grade distribution (spatial
variation and continuity).
Carol also notes that copper concentrate and kaolin have been produced from the area
covered by the tenement. The kaolin workings pique her interest, so she searches for
any data about its quality, namely its purity and the types of impurities present.
Her next step will be to review the nature of the gold occurrences and their
‘signature’, to predict areas where undiscovered mineralisation may occur. She notes
there are two main types of occurrence: ‘low sulphide Au–quartz vein’ (a type she
knows as ‘Mesozonal orogenic gold’), and ‘disseminated’ gold mineralisation.
She superimposes the locations of the mineral occurrences onscreen in her GIS
package over the geological units, structures and areas of alteration. Carol then
overlays the location of shafts and surface workings, to visually assess the spatial
relationships between the mineralisation and geological features. She may further
assess this information in a 3D modelling package.
She follows this review up with a more refined statistical assessment within the GIS
to understand the strength of the relationship between the gold occurrences, structures
and host rocks.
She uses past production statistics as a proxy for the gold endowment to differentiate
between the occurrences. Many of the workings have no statistics, though, so Carol
looks at other data, such as geochemical results and mineralogical characteristics of
each occurrence, to better understand the mineralised system and the potential for
large undiscovered deposits.
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When she has compiled the data she wants, she exports it to a statistical package for
further analysis. She also creates a map of the gold distribution and a report figure
showing the correlation between host rock, gold endowment and mineral deposit type
to take to the board meeting next week.
At the end of the investigation, Carol presents a report to the company’s management
detailing her findings, which shows the most prospective areas for gold occurrences of
the type they are interested in, as well as options for additional income from the
kaolin deposits.
Scenario 2
Description: a land use planner investigates potential resources within an area to aid
land use decisions.
Adam needs to provide an estimate of the dollar value of potential gold mineralisation
occurring on land currently home to a Box Ironbark Forest as part of the land use
planning process. Predicting this value will involve extracting data from a mineral
occurrence database that captures the deposit styles within the area and their attributes
(including metallurgical attributes).
The area is to the north of Bendigo, an area known for three important types of
deposit. Each of the deposit types has a specific structural style, geophysical and
geochemical signature, and alteration signature (as seen in regolith and
lithogeochemistry). These characteristics, along with the depth of cover rocks,
influence the mining methods that are suitable for each deposit, and hence the cost to
extract the gold.
He uses production figures, including recovered vs. in situ grades, to determine
existing and potential metal endowment from the mine workings to gain an idea of the
value of the potential mineralisation in the Bendigo Zone. He then estimates the value
of probable remaining gold based on the size of the area, its potential to host
occurrences of a similar size to those further south, the potential metal endowment of
those deposits and the depth of cover.
Scenario 3
Description: a mining engineer conducts a mine site hazard study.
Peter is a senior engineer at a mine in the Bendigo area, tasked with designing the
processing facilities to support the company’s new decline. He needs to know the
location of any historic workings on their Mining Lease as part of their OH&S
assessment, so that the new plant is built on stable ground and that people and
equipment moving around the site do not fall into any existing shafts.
Peter searches the mineral occurrences database for mine data, historic plans and
reports to determine where shafts, shallow drives and other mining features occur
within the Mining Lease. He reviews this and develops a plan (perhaps in 3D) which
allows him to assess where openings to workings are located, as well as the
underground extent of these workings. He notes that one of the proposed sites for the
tailings dam has a shallow drive under it, which rules it out, but that the site for their
new ore processing facility is in an area away from historic workings.
Additionally, the company are establishing a mineral reserve, so they need to identify
what has already been mined out. Peter extracts data relating to mine workings and
past production records, and locates them on historic mine plans. These help to
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delineate what has been taken from which level through past mining activity, so that a
more accurate mineral reserve can be calculated.
Scenario 4
Description: a project generation geologist examines mineral system potential.
Exploration Company, ExploreBig, explores for porphyry Cu-Au, but only in terrains
where the mineral systems were responsible for the deposition and preservation of
what they term ‘giant’ ore deposits.
Clare, a project generation geologist, sits in ExploreBig’s Canadian exploration office.
She enters the GeoScience Victoria website and begins her search of data sourced
from the Mineral Occurrence database.
She does a ‘find me” query in the Mineral Systems part of the Min Occ database –
searching for:
- the presence of an island arc or a convergent plate boundary (genesis
process and environment);
- geological units from I-type intrusions (which are either a potential source
or a host of the mineralisation);
- large scale structures (especially strike-slip faults) which are potential
paths for the porphyry mineralisation;
- porphyry-related (including porphyry-related skarn) Cu and Au prospects
or occurrences
She assesses this information for suitability of this combination of tectonic setting and
favourable geological units in the State of Victoria to contain mineral systems which
include Cu-Au porphyry deposits.
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