ALPPROJECT Cons. carries out a complex of field geological studies including field evaluations, exploration, mining, petrographic, mineralogical operations and other geological works. The consortium is experienced in implemeting the above operations, including contracts with such foreign companies as Cameco, Mitsui, Apex, Newmont, Barrick etc. The companies incorporated in the consortium employ staff of the highly skilled employees and all necessary devices and equipment, including computers furnished to work in field conditions, FM-radio communication units and other equipment.
In 2006-2007 ALPPROJECT Cons. in collaboration with emloyees of Micromine Pty Ltd. develops the unique method of 3D-modeling for estimation of prospected reserves on early stages of geological explorating works:
Exploration in mountainous regions has a number of
specific features that make the standard methods used in flat areas
inappropriate, ineffective and very expensive. Exploration drilling on a dense
regular grid that is used everywhere in a flat country, for example, cannot be
practically used in the mountains because it would require the construction of a
road to every drill pad that required blasting. This would involve a significant
investment of funds and take a considerable amount of time. Alternatively, hard
rock exposure in the mountains is good in most cases, and qualitative
examination of the area from the surface, that includes mapping and sampling,
makes it possible to define an in-depth structural model of the ore zones for
minimal cost and within a short period of time. Therefore, we suggest that the
method described below is the most appropriate and cost effective method for
early-stage exploration in mountainous regions.
Stage 1: The collection of historical data
At this stage, a detailed knowledge and understanding
of the target area and its flanks must be developed. Historical reports,
topographic maps, aerial photos and space images must all be collated. Verbal
and written consultations must be undertaken with any specialists who were
working in the target area and adjoining areas in the past. All pertinent and
potentially useful information must be identified and extracted from the
collected material.
Stage 2: The processing of
documentation and the georeferencing of maps and images
At this stage all historical material is analysed and sorted. Further
processing is as follows:
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Documents are scanned and compiled
as electronic books with a user-friendly system of internal and external hyperlinks.
Specifically each book should have hyperlinks from the table of contents to
each chapter of the book, and there should also be hyperlinks from the table
of contents to scanned maps, schemas, sampling plans and other related material
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Images and maps should be scanned
at both a high and a low resolution; high resolution for further processing
and analysis, low resolution for hyperlinks in associated documentation
As a result, a well-organised and easily accessible
electronic library of historical material is compiled, which eliminates any
further use of (often fragile or poor quality) paper documentation. Further
processing of high resolution images and maps involves the selection of any
images or maps that can potentially be georeferenced using the coordinate system
that will be used for all future project work. This selection process will
usually include all geological maps, sampling plans and field work maps. It is
essential that all existing topography maps (largest scale available), aerial
photos and space images are also included. Each selected map is loaded and
georeferenced using MICROMINE or a desktop GIS software application. Before
georeferencing, all raster images must be ortho-rectified to remove any
deformations and distortions. After this has been done, the maps should be
georeferenced using the UTM WGS 1984 coordinate system, which is widely-used and
considered to be GPS compatible.
Stage 3: Digitising of historical maps
At this stage, all relevant spatial information is
digitised from the rectified and georeferenced maps. Spot heights, elevation
contours, falls, rivers, creeks, roads and trails are digitised from topographic
maps. An important task at this stage will be to assign elevation values to
contours and spot heights. Once this has been done, aerial photographs can be
georeferenced using the topographical data obtained. This will provide a
spatially accurate photo plan. Ore bodies, ore zones and spots, anomaly zones
and spots, ore occurrences, samples and all workings should be digitised from
geological maps.
Stage 4: Field work. Phase 1
Once all the spatial data has been computerised and arranged as a multi-layered thematic map, the first phase of field work can be planned. During this initial phase, the areas in which different types of field work will occur must be identified. In most cases, field work will involve the detailed structural mapping of prospective areas, together with a detailed study of the zones of jointing at the points of reference, sampling along geological traverses, formation sampling for petrographical and mineralogical analysis, geochemical soil sampling on a regular grid, the photography of outcrops, alteration zones, and bed rock and formation samples. The resampling of previous workings is also applicable. During field work it will also be necessary to record the GPS position of all previous workings found in geological traverses and other indicative points of the landscape (height points, junctions of the rivers etc). This must be done in order to correct the georeferencing that was applied to previous maps and particularly sampling plans. The point to note is that even published topography maps can have a bias up to one millimetre in map scale. After analysing the GPS positions, an average map offset can be calculated and used to correct the georeferencing of raster and vector maps.
A report of the field work should be presented on CD or
DVD and should contain the following:
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Register of samples
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Brief text report in HTML
format with photos
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Scanned primary field
documentation
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Geological map and map of the
field works as multi-layer GIS map with legends and hyperlinks to primary field
documentation, photos and geological sections
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Legend to geological map that
shows the history of geological aspects of the studied area, including
compositional petrology and all accompanying processes such as ore parent. The
legend is available in a spreadsheet or image.
Stage 5: Field work. Phase 2
The second phase of field work must be carefully
planned. Assay results are posted to corresponding layers of the reporting map,
thematic layers with grades and geochemical anomalies are created. At this stage
a 3D model of the area is generated using MICROMINE software. This model should
include all the data described previously, all historical sampling data,
drillhole data etc. To be able to build a model, attributes such as strike, dip,
age, depth and priority of all contacts, faults and thrusts must be specified.
Even based on a relatively small amount of sampling data, a qualitative 3D model
of the area can be built at this stage. During the modelling process the
structure will be identified and prospective ore zones will be modelled to the
correct depth. The derived model can be used for the estimation of prospective
unclassified resources. However the main goal of this modelling activity is be
able to visualise the whole area and its anomalous zones in 3D, and be able to
quickly generate cross-sections in any direction. This allows for the
identification of the most prospective zones so that further field work can be
scheduled in those zones. This work will involve setting accurate locations and
directions for drilling so that a minimal amount of drillholes need to be
drilled in order to confirm and correct the model. The second phase of field
work can thus be planned in the most accurate, optimal and cost effective way.
The results of this work (even negative) will serve to correct the model further,
and provide a truer picture of the area under investigation.
Once it is reasonable to start field work within
identified prospective zones, the field work will include the following:
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Geochemical sampling on the
dense grid
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Qualitative collection of
standard samples from trenching and bulldozer stripping. This type of sampling
can be set equal to the drilling of the horizontal holes, although it is much
quicker and cheaper than drilling
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Construction of the roads to
one or several drill pads and drilling holes with strictly specified azimuth and
dip
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A high detailed topographic
survey by means of high precision GPS, DGPS and Total Stations. These tools
are also used for high precision survey of the drillhole collars, trenches and
bulldozer stripping
Stage 6: Field work. Phase 3
Phase 3 will also need to be carefully planned. Assay
results from the previous stage will be posted to the corresponding layers of
the reporting map and the 3D model. Thematic layers with grades and geochemical
anomalies will be updated. The 3D model will be updated with assay results and
the prospective areas will be corrected. The 3D model will improve more and more
as each new package of data is applied. If the assay data is sufficient, then it
will be possible to label prospective zones in the model as ore zones, ore
blocks or even ore bodies. Resource estimation and classification can then be
conducted.
If the assay data or other data is insufficient, then
further field work for phase 3 should be planned which includes the following:
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Qualitative collection of standard
samples from trenching and bulldozer stripping
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Construction of the roads to
one or several drill pads and drilling holes with strictly specified azimuth and
dip
At the completion of this work and after getting back the assay results from the lab, the reporting map and the model can be updated. The amount of data in the model now should allow a full resource estimation and classification of the area to be conducted. At this stage our goal is achieved. Further stages of field work are not considered relevant to the early-stages of exploration of mineral deposits. However, the 3D model created during these early stages will be an essential input during later stages, including pit design and mining. This is an important benefit of the proposed method.